TWI792195B - Photocurable adhesive sheet, adhesive sheet, and image display device - Google Patents

Abstract

The present invention provides an adhesive sheet that can follow the step of the bonding surface and fill to every corner, and can easily carry out the bonding operation without reducing the bonding reliability even if it is exposed to light for a long time. Therefore, the present invention proposes an adhesive sheet, which is characterized in that: it is formed from a resin composition containing a (meth)acrylic copolymer (A), a crosslinking agent (B) and a photopolymerization initiator (C) Adhesive sheet before light hardening, and has light hardening, and has the following characteristics of (1) and (2). (1) It can maintain its shape at 0-40°C and exhibit self-adhesiveness. (2) Viscosity at 70-100°C is 100-3000 Pa·s.

Description

Photocurable adhesive sheet, adhesive sheet, and image display device

The present invention relates to a photocurable adhesive sheet before photocuring and an adhesive sheet obtained by photocuring it. In detail, it relates to an image display device that can be preferably used as a computer, mobile terminal (PDA), game console, television (TV), car navigation, touch panel, tablet, etc. and the adhesion of its constituent components Sheet.

In recent years, in order to improve the visibility of image display devices, image display panels such as liquid crystal displays (LCDs), plasma displays (PDPs) or electroluminescent displays (ELDs) are arranged on the front side (recognition side) ) between the protective panel or the touch panel components are filled with an adhesive sheet or a liquid adhesive to suppress the reflection of incident light or outgoing light from a display image at the interface of the air layer.

As a method of filling the gaps between constituent members of such an image display device with an adhesive, there is known a method of filling the gaps with a liquid adhesive resin composition containing an ultraviolet curable resin and then irradiating it with ultraviolet rays to harden it. (Patent Document 1).

Moreover, the method of filling the gap between the constituent members for image display devices using an adhesive sheet is also known. For example, in Patent Document 2, as a method for producing a laminate for image display device constituting a structure in which image display device constituent members are laminated on at least one side of an adhesive sheet, primary crosslinking by ultraviolet rays is disclosed. After the adhesive sheet is bonded to the components of the image display device, the adhesive sheet is irradiated with ultraviolet rays through the components of the image display device to make it secondary harden.

Also, it is disclosed in Patent Document 3 that the use of a weight average molecular weight of 20,000 to 100,000 A sheet of a hot-melt adhesive composition whose loss tangent at 25°C is less than 1 with (meth)urethane acrylate as the main component.

Furthermore, Patent Document 4 discloses a (meth)acrylic polymer obtained by copolymerizing a monomer containing a (meth)acrylic monomer having a crosslinkable functional group and a specific macromonomer. , and a cross-linking agent suitable for bonding the adhesive layer of the touch panel.

[Prior Art Literature] [Patent Document]

[Patent Document 1] International Publication No. 2010/027041

[Patent Document 2] International Publication No. 2012/032995

[Patent Document 3] International Publication No. 2010/038366

[Patent Document 4] Japanese Patent Laid-Open No. 2013-18227

[Patent Document 5] Japanese Patent Laid-Open No. 2012-184423

In the field of image display devices centered on mobile phones and mobile terminals, in addition to thinning and high precision, the diversification of design is also progressing, and new issues have arisen along with it. For example, a frame-shaped black concealed portion is usually printed on the periphery of the surface protection panel. Therefore, an adhesive sheet for bonding components having such a printed portion is required to have printing level followability that can follow the printing level and fill to every corner.

In addition, image display devices such as touch panels are widely used. Along with this, adhesive sheets used in laminates for image display devices are required to have properties that are durable even when exposed to light such as lighting or sunlight for a long time. Will not reduce the reliability of performance.

The first object of the present invention is to provide a novel adhesive sheet which is pre-cured by light In this state, it can follow the step of the bonding surface and fill to every corner, and even if it is exposed to light for a long time in the state after photohardening, the bonding reliability will not be reduced, so that the bonding operation can be easily performed.

The second object of the present invention is to provide a novel adhesive sheet, which can be adhered to a constituent member for an image display device having an opaque portion such as a printed portion and a light-transmitting portion in the bonding surface. It can obtain the followability or surface flatness of the step part, etc., and there will be no strain or deformation in the opaque part, and it can have a high cohesive force to firmly bond the adherends to each other. Furthermore, Even in harsh environments such as high temperature and high humidity, the exposed adhesive surface can be kept from sticking.

The third object of the present invention is to provide an adhesive sheet, which is photocrosslinkable and has adhesiveness before photocrosslinking, so that the adhesive will not flow too much and cause the adhesive resin composition to overflow or Crushing, and then photo-crosslinking can obtain sufficient hardness.

In order to achieve the first object, the present invention proposes the above-mentioned adhesive sheet, which is characterized in that: it is composed of (meth)acrylic copolymer (A), crosslinking agent (B) and photopolymerization initiator (C) The adhesive sheet formed by the resin composition before photocuring is photocurable and has the following characteristics (1) and (2).

(1) It can maintain its shape at 0~40℃ and shows self-adhesiveness.

(2) The viscosity shows 100~3000Pa‧s at 70~100℃.

The above-mentioned adhesive sheet proposed by the present invention to achieve the first object can maintain the shape of the sheet at a room temperature of 0 to 40°C, that is, under normal conditions, and can exhibit self-adhesiveness, so it is easy to handle and can be bonded efficiently. , For example, positioning when sticking can be easily performed. In addition, when the temperature is 70-100°C, the viscosity becomes 100-3000 Pa‧s, showing heat-fusibility, so for example, it is possible to fill the adhesive with the irregularities such as printing steps. Furthermore, it exhibits higher cohesion after photohardening, such as It exhibits excellent foaming resistance even after long-term light exposure, and will not reduce bonding reliability even after long-term light exposure. Therefore, the photocurable adhesive sheet proposed by the present invention can be preferably used as an image display device such as a computer, a mobile terminal (PDA), a game machine, a television (TV), a car navigation, a touch panel, a tablet, etc. the constituent components.

In order to achieve the second object, the present invention proposes an adhesive sheet, which is characterized in that it contains a (meth)acrylic copolymer (A) and is light-cured, and has a gel fraction of less than 1%. The sheet part and the sheet part with a gel fraction of 40% or more.

The above-mentioned adhesive sheet proposed by the present invention to achieve the second object can obtain followability or surface flatness to the step portion and the like by the sheet portion with a gel fraction of less than 1%, and can alleviate the stress in the sheet. Strain or deformation. On the other hand, the sheet with a gel fraction of 40% or more can not only make the adhesive surface not sticky, but also have a high cohesive force to firmly bond the adherends to each other.

Therefore, for example, even in the case of bonding to a constituent member for an image display device having an opaque portion such as a printed portion and a light-transmitting portion in the bonding surface, it is possible to obtain a print level difference as a whole of the adhesive sheet. The followability or surface flatness of the part does not cause strain or deformation in the opaque part, and furthermore, it can have a high cohesive force to firmly bond the adherends to each other. Also, by using the exposed adhesive surface as a hard portion, the exposed adhesive surface can be kept from sticking even under severe environments such as high temperature and high humidity.

In order to achieve the third object, the present invention proposes an adhesive sheet, which is characterized in that it contains 100 parts by mass of (meth)acrylic copolymer (A), 0.5 to 20 parts by mass of crosslinking agent (B) and light A polymerization initiator (C) of 0.1 to 5 parts by mass of the resin composition, and the ratio of the tensile modulus of elasticity (X1) before photocrosslinking to the tensile modulus of elasticity (X2) after photocrosslinking (X1 /X2) becomes 3 or more.

The above-mentioned adhesive sheet proposed by the present invention to achieve the third object has the characteristic that the difference in tensile elastic modulus (X1) before and after photocrosslinking is significantly large, and it has adhesiveness even before photocrosslinking When the adhesive material does not flow too much, the adhesive resin composition will overflow or collapse, and sufficient hardness can be obtained after photo-crosslinking.

2: Adhesive sheet

21: sheet surface

22: soft part

23: Hard part

24: end face

25: Release film

Fig. 1 is a top perspective view showing an example of the adhesive sheet of the present invention.

Fig. 2 is a top perspective view showing another example of the adhesive sheet of the present invention.

3(A) and (B) are top perspective views showing another example of the adhesive sheet of the present invention.

Fig. 4 is a diagram of an example of an adhesive sheet laminate provided with the adhesive sheet shown in Fig. 3(B), (A) is a top perspective view thereof, and (B) is a cross-sectional view.

Fig. 5 is a top perspective view showing another example of the adhesive sheet of the present invention.

Hereinafter, an example of an embodiment of the present invention will be described in detail. However, the present invention is not limited to the following embodiments.

[this adhesive sheet 1]

The adhesive sheet (referred to as "this adhesive sheet 1"), which is an example of the embodiment of the present invention, is characterized in that it is made of a (meth)acrylic copolymer (1-A), a crosslinking agent (1- B) and the resin composition of the photopolymerization initiator (1-C) (referred to as "this adhesive composition 1") is an adhesive sheet before photocuring, and has photocurability, and has the following ( 1) and (2) characteristics.

(1) It can maintain its shape at 0~40℃ and shows self-adhesiveness.

(2) The viscosity shows 100~3000Pa‧s at 70~100℃.

Here, the so-called "adhesive sheet before photocuring" may be a photocurable adhesive sheet, and does not only refer to an adhesive sheet that has not undergone photocuring at all. That is, for example, if it is an adhesive sheet that can be further photocured through a photocuring step and can exhibit the effect of the present invention, it is included in the present invention.

This adhesive sheet 1 has the characteristics of (1) and (2) above in the state before photohardening, so it can maintain the sheet shape at room temperature of 0~40°C, in other words, it has self-adhesiveness. In the original state to play the nature of adhesive force. Furthermore, it exhibits hot-melt properties that melt or flow when heated, exhibits excellent cohesive force after photohardening, and exhibits foaming resistance after long-term light irradiation, for example.

<Characteristics at room temperature>

The present adhesive sheet 1 has (1) the characteristics of maintaining the shape of the sheet at a room temperature of 0-40° C. and exhibiting self-adhesiveness in the state before photohardening.

In this way, if the sheet shape can be maintained at room temperature, that is, under normal conditions, handling is easy, and the productivity of laminated members is particularly excellent. Furthermore, if self-adhesiveness is exhibited under normal conditions, for example, positioning at the time of sticking is easy, and the sticking operation is very convenient.

In order to obtain such a characteristic, what is necessary is just to manufacture this adhesive sheet 1 from the following adhesive composition (1-I) or (1-II), for example. But it is not limited to this.

(180°peel force at 23°C, 40%RH)

The present adhesive sheet 1 may have the following feature (6). That is (6) when it is crimped on the soda-lime glass, at 23°C and 40% RH, at a peeling angle of 180° and a peeling speed of 60mm/min, the adhesive sheet 1 is peeled off from the above-mentioned soda-lime glass. ° The peeling force may be 3 N/cm or more. By setting the 180° peeling force at 23°C to 3 N/cm or more, it has moderate adhesion to the adherend at room temperature and excellent bonding workability, so it is preferable.

From this point of view, the 180° peel force of the present adhesive sheet 1 at 23° C. and 40% RH is preferably 3 N/cm or more, preferably 20 N/cm or less, particularly preferably 4 N/cm or more or Below 15N/cm.

In this adhesive sheet 1, in order to adjust the 180° peel force at 23°C and 40%RH, for example, from The following adhesive composition (1-I) or (1-II) is used to manufacture this adhesive sheet 1, and then adjust the type or composition ratio of the crosslinking agent or photopolymerization initiator, or adjust the heating, adding Pressing conditions or light irradiation conditions after lamination are sufficient. However, it is not limited to this method.

<Characteristics when heated at 70~100°C>

The present adhesive sheet 1 has (2) the viscosity becomes 100-3000 Pa‧s when heated to 70-100° C. before photocuring, showing fluidity.

If the present adhesive sheet 1 has such hot-melt properties, it can be softened or fluidized by heating, and the adhesive can be filled with the uneven parts such as printing steps. filling.

In order to obtain such a characteristic, what is necessary is just to manufacture this adhesive sheet 1 from the following adhesive composition (1-I) or (1-II), for example. But it is not limited to this.

When the adhesive sheet 1 is heated to 70-100° C., the viscosity becomes 100-3000 Pa‧s, preferably 150 Pa‧s or 2700 Pa‧s, more preferably 200 Pa‧s or 2500 Pa‧s.

(180°peel force at 80°C, 10%RH)

The present adhesive sheet 1 may have the following feature (7). That is, (7) When it is crimped on soda-lime glass, at 80°C and 10% RH, the peeling mode when peeling this adhesive sheet 1 from the above-mentioned soda-lime glass is agglomeration at a peeling angle of 180° and a peeling speed of 60mm/min Destruction, the 180°peeling force to glass can be less than 1N/cm.

If the 180° peeling force at 80°C is 1 N/cm or less, high wettability to the adherend can be obtained, which is preferable.

From this point of view, the 180° peeling force of the present adhesive sheet 1 at 80°C and 10% RH is preferably 1 N/cm or less, more preferably 0.8 N/cm or less, particularly preferably 0.5 N/cm the following.

In this adhesive sheet 1, in order to adjust the 180° peel force at 80°C and 10% RH, this adhesive sheet 1 is manufactured from the following adhesive composition (1-I) or (1-II), for example, and then Just adjust the type or composition ratio of the crosslinking agent or photopolymerization initiator, or adjust the heating and pressurizing conditions during bonding or the light irradiation conditions after bonding. However, it is not limited to this method.

<Characteristics after photocuring>

This adhesive sheet 1 can be photocured, and has (3) the characteristic that after photocuring, the viscosity at 70~100°C becomes 3000~50000 Pa‧s.

From the viewpoint of obtaining higher cohesion, the viscosity of the adhesive sheet 1 at 70-100°C after light curing is preferably 3000-50000 Pa‧s, more preferably 3500 Pa‧s or more 48000Pa‧s or less, and more preferably 4000Pa‧s or more or 45000Pa‧s or less.

(180°peel force at 23°C, 40%RH after light curing)

The adhesive sheet 1 can have the following feature (4) after photocuring. That is, (4) pressure-bonded on soda-lime glass, as a light-cured adhesive sheet hardened by light irradiation, at 23°C and 40%RH, at a peeling angle of 180° and a peeling speed of 60mm/min, from the above-mentioned sodium When the lime glass peels off the adhesive sheet, the 180° peeling force against the glass can be more than 3N/cm.

If the 180° peel force at 23° C. after photocuring is 3 N/cm or more, adherends can be firmly bonded together, which is preferable.

From this point of view, the 180° peeling force at 23° C. after photocuring of the present adhesive sheet 1 is preferably 3 N/cm or more, more preferably 4 N/cm or more, particularly preferably 5 N/cm or more, or Below 30N/cm.

(180°peel force at 80°C, 10%RH after light curing)

The adhesive sheet 1 can have the following feature (5) after photocuring. That is (5) crimping on sodium calcium On the glass, as the photohardened adhesive sheet hardened by light irradiation, at 80°C and 10% RH, at a peeling angle of 180° and a peeling speed of 60mm/min, the adhesive sheet is peeled from the above-mentioned soda-lime glass. The 180° peeling force of the glass can be above 3N/cm.

If the 180° peeling force at 80° C. after photocuring is 3 N/cm or more, the foaming resistance in a high-temperature environment is excellent, so it is preferable.

From this point of view, the 180° peel force at 80° C. after photocuring of the present adhesive sheet 1 is preferably 3 N/cm or more, more preferably 4 N/cm or more, particularly preferably 5 N/cm or more, or Below 20N/cm.

In this adhesive sheet 1, in order to adjust the 180° peel force at 23°C or 80°C after photocuring, this adhesive sheet is produced from the following adhesive composition (1-I) or (1-II), for example 1. Further adjust the type or composition ratio of the crosslinking agent or photopolymerization initiator, or adjust the heating and pressure conditions during lamination or the light irradiation conditions after lamination. However, it is not limited to this method.

<Outgas generation amount>

The amount of outgassing of the adhesive sheet 1 after light hardening after 24 hours of light irradiation by the xenon arc lamp light resistance tester specified in JIS K7350-2 (ISO4892-2), preferably in hexadecane conversion It is above 40000ppm.

When the amount of outgassing is 40,000 ppm or more in terms of cetane, it is preferable because the viscosity of the adhesive sheet or the wettability to the adherend will increase.

Therefore, from this point of view, the amount of outgassing in the present adhesive sheet 1 is preferably 40,000 ppm or more in terms of cetane, more preferably 45,000 ppm or more, and especially preferably 50,000 ppm or more.

In addition, in order to make the said outgassing amount in this adhesive sheet 1 into the said range, what is necessary is just to manufacture this adhesive sheet 1 from the following adhesive composition (1-I) or (1-II), for example. But it is not limited to this.

<Reliability against foaming>

It is preferable that this adhesive sheet 1 after photocuring exhibits foaming resistance in which the diameter of the bubbles is 5 mm or less in the following foaming resistance test.

Foaming resistance test: The adhesive sheet is sandwiched between two glass plates with a diagonal length of 5 inches or more and a thickness of 1mm or less to make a laminate, according to JIS K7350-2 (ISO4892-2), by Xenon-arc light resistance testing machine measures the diameter of bubbles generated in the adhesive sheet after 24 hours of light irradiation.

This adhesive sheet 1 has the characteristic that the viscosity at 70~100°C becomes 3000~50000 Pa‧s after photocuring, so it can show such foaming resistance after photocuring. Therefore, it can exhibit the property that the reliability will not be lowered even if it is exposed to light for a long time, so it can be used in various image display devices, even if it is exposed to light such as lighting or sunlight for a long time, it can be obtained. sex.

In order to obtain such a characteristic, what is necessary is just to manufacture this adhesive sheet 1 from the following adhesive composition (1-I) or (1-II), for example. But it is not limited to this.

<This adhesive composition 1>

As a preferable example of the adhesive composition 1 used in the production of the adhesive sheet 1, an acrylic copolymer (1-A1) containing a graft copolymer having a macromonomer as a branch component can be cited. ), an adhesive composition (1-I) of a crosslinking agent (1-B1) and a photopolymerization initiator (1-C1).

In addition, as another example of the present adhesive composition 1, monomer a1 containing a glass transition temperature (Tg) of less than 0°C and a monomer having a glass transition temperature (Tg) of 0°C or higher and less than 80°C can be cited. Monomer a2 and monomer a3 with a glass transition temperature (Tg) above 80°C are copolymerized at a molar ratio of a1:a2:a3=10~40:90~35:0~25, and the weight average molecular weight is 50000~400000 (meth)acrylic copolymer (1-A2); crosslinking agent (1-B2) and photopolymerization initiator (1- C2) The adhesive composition (1-II).

Wherein, the adhesive composition used to form the adhesive sheet 1 is not limited to the adhesive composition (1-I) or (1-II).

In addition, the number average molecular weight and weight average molecular weight are conversion values using polystyrene as a standard substance using gel permeation chromatography (GPC).

If this adhesive sheet 1 is produced from the adhesive composition (1-I) or (1-II) prepared by a known method, it can maintain a sheet shape at room temperature and exhibit self-adhesiveness, and has a property equivalent to In the uncrosslinked state, it melts or flows when heated, and can be photohardened. After photohardening, it exhibits excellent cohesive force.

<Adhesive composition (1-I)>

Examples of the adhesive composition (1-I) include: an acrylic copolymer (1-A1) containing a graft copolymer having a macromonomer as a branch component, a crosslinking agent (1-B1), and a photopolymer. Adhesive composition of a polymerization initiator (1-C1).

(Acrylic Copolymer (1-A1))

The acrylic copolymer (1-A1) as the base polymer may be a graft copolymer having a macromonomer as a branch component.

(main ingredient)

It is preferable that the backbone component of the said acrylic-type copolymer (1-A1) contains the copolymer component containing the repeating unit derived from (meth)acrylate.

The glass transition temperature of the copolymer constituting the main component of the acrylic copolymer (1-A1) is preferably -70 to 0°C.

In this case, the glass transition temperature of the copolymer component constituting the main component refers to a polymer obtained by copolymerizing only the monomer components constituting the main component of the acrylic copolymer (1-A1). the glass transition temperature. Specifically, it refers to the value calculated by Fox's calculation formula from the glass transition temperature and composition ratio of the polymer obtained from the homopolymer of the respective components of the copolymer.

In addition, the calculation formula of Fox means the calculated value obtained by the following formula, and can be obtained using the value described in the polymer handbook [Polymer Handbook, J. Brandrup, Interscience, 1989].

1/(273+Tg)=Σ(Wi/(273+Tgi))

[Where, Wi represents the weight fraction of monomer i, and Tgi represents the Tg (°C) of the homopolymer of monomer i]

The glass transition temperature of the copolymer component constituting the main component of the acrylic copolymer (1-A1) affects the flexibility of the adhesive composition (1-I) at room temperature, or the adhesive composition (1-A1) I) It affects the wettability of the adherend, that is, the adhesiveness, so in order to make the adhesive composition (1-I) obtain moderate adhesiveness (viscosity) at room temperature, the glass transition temperature is better -80°C to 0°C, more preferably -75°C or higher or -5°C or lower, particularly preferably -70°C or higher or -10°C or lower.

Among them, even if the glass transition temperature of the copolymer components is the same temperature, the viscoelasticity can be adjusted by adjusting the molecular weight. For example, by reducing the molecular weight of the copolymer component, it can be made more flexible.

基酯、(甲基)丙烯酸2-苯氧基乙酯、丙烯酸3,5,5-三甲基環己酯、對異丙苯基苯酚EO改性(甲基)丙烯酸酯、(甲基)丙烯酸二環戊酯、(甲基)丙烯酸二環戊烯酯、(甲基)丙烯酸二環戊烯氧基乙酯、(甲基)丙烯酸苄酯等。亦可使用該等中具有親水基或有機官能基等之(甲基)丙烯酸羥乙酯、(甲基)丙烯酸羥丙酯、(甲基)丙烯酸羥丁酯、(甲基)丙烯酸甘油酯等含羥基之(甲基)丙烯酸酯，或(甲基)丙烯酸、2-(甲基)丙烯醯氧基乙基六氫鄰苯二甲酸、2-(甲基)丙烯醯氧基丙基六氫鄰苯二甲酸、2-(甲基)丙烯醯氧基乙基鄰苯二甲酸、2-(甲基)丙烯醯氧基丙基鄰苯二甲酸、2-(甲基)丙烯醯氧基乙基順丁烯二酸、2-(甲基)丙烯醯氧基丙基順丁烯二酸、2-(甲基)丙烯醯氧基乙基琥珀酸、2-(甲基)丙烯醯氧基丙基琥珀酸、丁烯酸、反丁烯二酸、順丁烯二酸、伊康酸、順丁烯二酸單甲酯、伊康酸單甲酯等含羧基之單體，順丁烯二酸酐、伊康酸酐等含酸酐基之單體，(甲基)丙烯酸縮水甘油酯、α-乙基丙烯酸縮水甘油酯、(甲基)丙烯酸3,4-環氧丁酯等含環氧基之單體，(甲基)丙烯酸二甲胺基乙酯、(甲基)丙烯酸二乙胺基乙酯等含胺基之(甲基)丙烯酸酯系單體，(甲基)丙烯醯胺、N-第三丁基(甲基)丙烯醯胺、N-羥甲基(甲基)丙烯醯胺、N-甲氧基甲基(甲基)丙烯醯胺、N-丁氧基甲基(甲基)丙烯醯胺、二丙酮丙烯醯胺、順丁烯二醯胺、順丁烯二醯亞胺等含醯胺基之單體，乙烯基吡咯啶酮、乙烯基吡啶、乙烯基咔唑等雜環系鹼性單體等。 Examples of the (meth)acrylate monomer contained in the main component of the acrylic copolymer (1-A1) include: methyl (meth)acrylate, ethyl (meth)acrylate, (meth)acrylate Propyl acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, second-butyl (meth)acrylate, third-butyl (meth)acrylate , Amyl (meth)acrylate, Isopentyl (meth)acrylate, Neopentyl (meth)acrylate, Hexyl (meth)acrylate, Cyclohexyl (meth)acrylate, Heptyl (meth)acrylate ester, 2-ethylhexyl acrylate, n-octyl acrylate, isooctyl acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, tertiary butylcyclohexyl (meth)acrylate, Decyl (meth)acrylate, Isodecyl (meth)acrylate, Undecyl (meth)acrylate, Lauryl (meth)acrylate, Cetyl (meth)acrylate, (Meth)acrylate ) stearyl acrylate, isostearyl (meth)acrylate, behenyl (meth)acrylate, iso(meth)acrylate

Base ester, 2-phenoxyethyl (meth)acrylate, 3,5,5-trimethylcyclohexyl acrylate, p-cumylphenol EO modified (meth)acrylate, (meth) Dicyclopentyl acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, benzyl (meth)acrylate, and the like. Hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, glycerin (meth)acrylate etc. which have a hydrophilic group or an organic functional group etc. can also be used Hydroxyl-containing (meth)acrylate, or (meth)acrylic acid, 2-(meth)acryloxyethylhexahydrophthalic acid, 2-(meth)acryloxypropylhexahydro Phthalic acid, 2-(meth)acryloxyethylphthalic acid, 2-(meth)acryloxypropylphthalic acid, 2-(meth)acryloxyethylphthalic acid 2-(meth)acryloxypropylmaleic acid, 2-(meth)acryloxyethylsuccinic acid, 2-(meth)acryloxypropylmaleic acid, 2-(meth)acryloxypropylmaleic acid Carboxyl group-containing monomers such as propyl succinic acid, crotonic acid, fumaric acid, maleic acid, itaconic acid, monomethyl maleate, monomethyl itaconate, etc. Monomers containing acid anhydride groups such as diacid anhydride and itaconic anhydride, glycidyl (meth)acrylate, α-glycidyl ethacrylate, 3,4-epoxybutyl (meth)acrylate, etc. containing epoxy groups Monomers, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate and other amino-containing (meth)acrylate monomers, (meth)acrylamide, N-tert-butyl (meth)acrylamide, N-hydroxymethyl (meth)acrylamide, N-methoxymethyl (meth)acrylamide, N-butoxymethyl ( Meth)acrylamide, diacetoneacrylamide, maleimide, maleimide and other amido-containing monomers, vinylpyrrolidone, vinylpyridine, vinylcarbazole Heterocyclic basic monomers, etc.

Moreover, it is also possible to appropriately use Combined styrene, tertiary butyl styrene, α-methyl styrene, vinyl toluene, acrylonitrile, methacrylonitrile, vinyl acetate, vinyl propionate, alkyl vinyl ether, hydroxyalkyl ethylene Various vinyl monomers such as base ethers and alkyl vinyl monomers.

Moreover, it is preferable that the backbone component of an acryl-type copolymer (1-A1) contains a hydrophobic (meth)acrylate monomer and a hydrophilic (meth)acrylate monomer as a structural unit.

If the main component of the acrylic copolymer (1-A1) is composed of only hydrophobic monomers, it is confirmed that there is a tendency of wet heat whitening. Therefore, it is preferable to introduce a hydrophilic monomer into the main component to prevent wet heat whitening.

Specifically, as the main component of the above-mentioned acrylic copolymer (1-A1), a combination of a hydrophobic (meth)acrylate monomer, a hydrophilic (meth)acrylate monomer, and a macromonomer can be mentioned. A copolymer component formed by random copolymerization of polymerizable functional groups at the terminal.

基酯、(甲基)丙烯酸環己酯、(甲基)丙烯酸二環戊烯氧基乙酯、甲基丙烯酸甲酯。 Here, as the above-mentioned hydrophobic (meth)acrylate monomer, alkyl esters having no polar groups (among which, methyl acrylate is not included) are preferred, for example, n-butyl (meth)acrylate , Isobutyl (meth)acrylate, second butyl (meth)acrylate, third butyl (meth)acrylate, pentyl (meth)acrylate, isoamyl (meth)acrylate, (meth) ) Neopentyl acrylate, (meth)hexyl acrylate, (meth)cyclohexyl acrylate, (meth)heptyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, isooctyl acrylate, ( Nonyl methacrylate, isononyl (meth)acrylate, tert-butylcyclohexyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, (meth) Undecyl acrylate, lauryl (meth)acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, (meth)acrylic acid Behenyl Ester, (Meth) Acrylic Iso

base ester, cyclohexyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, methyl methacrylate.

In addition, examples of hydrophobic vinyl monomers include vinyl acetate, styrene ene, tertiary butylstyrene, α-methylstyrene, vinyltoluene, alkyl vinyl monomers, etc.

As the above-mentioned hydrophilic (meth)acrylate monomer, methyl acrylate or an ester having a polar group is preferable, for example, methyl acrylate, (meth)acrylic acid, tetrahydrofurfuryl (meth)acrylate Or (meth)acrylate or (meth)acrylate containing hydroxyl groups such as hydroxyethyl (meth)acrylate, (meth)hydroxypropyl Acrylic acid, 2-(meth)acryloxyethyl hexahydrophthalate, 2-(meth)acryloxypropyl hexahydrophthalate, 2-(meth)acryloxy Ethylphthalate, 2-(meth)acryloxypropylphthalate, 2-(meth)acryloxyethylmaleic acid, 2-(meth)acrylyl Oxypropylmaleic acid, 2-(meth)acryloxyethylsuccinic acid, 2-(meth)acryloxypropylsuccinic acid, crotonic acid, fumaric acid, Carboxyl group-containing monomers such as maleic acid, itaconic acid, monomethyl maleate, and monomethyl itaconate, acid anhydride group-containing monomers such as maleic anhydride and itaconic anhydride, ( Epoxy group-containing monomers such as glycidyl methacrylate, glycidyl α-ethacrylate, 3,4-epoxybutyl (meth)acrylate, etc., methoxypolyethylene glycol (methyl) Alkoxy polyalkylene glycol (meth)acrylate such as acrylate, N,N-dimethylacrylamide, hydroxyethylacrylamide, etc.

(branch components: macromonomer)

The acrylic copolymer (1-A1) preferably introduces a macromonomer as a branch component of the graft copolymer and contains repeating units derived from the macromonomer.

The so-called macromonomer system refers to a polymer monomer having a terminal polymerizable functional group and a high molecular weight skeleton component.

The glass transition temperature (Tg) of the macromonomer is preferably higher than the glass transition temperature of the copolymer components constituting the above-mentioned acrylic copolymer (1-A1).

Specifically, the glass transition temperature (Tg) of the macromonomer will add to the adhesive composition (1-I). The thermal melting temperature (hot melting temperature) has an influence, so the glass transition temperature (Tg) of the macromonomer is preferably 30°C~120°C, more preferably 40°C or higher or 110°C or lower, and even more preferably 50°C above or below 100°C.

If it is such a glass transition temperature (Tg), by adjusting the molecular weight, it is possible to maintain excellent processability and storage stability, and it can be adjusted to heat-melt around 80°C.

The so-called glass transition temperature of the macromonomer refers to the glass transition temperature of the macromonomer itself, which can be measured by a differential scanning calorimeter (DSC) (heating rate: 5°C/min, based on the inflection point of the baseline displacement Determination of Tg).

In addition, in order to maintain the branched components close to each other at room temperature, as the adhesive composition undergoes physical cross-linking, and by heating to a moderate temperature, the above-mentioned physical cross-linking can be released to obtain fluidity It is also preferable to adjust the molecular weight or content of the macromonomer.

From this point of view, the macromonomer is preferably contained in the acrylic copolymer (1-A1) at a ratio of 5 mass % to 30 mass %, more preferably 6 mass % or more or 25 mass % or less, wherein More preferably, it is 8 mass % or more or 20 mass % or less.

Also, the number average molecular weight of the macromonomer is preferably 500 or more and less than 8000, more preferably 800 or more and less than 7500, and still more preferably 1000 or more and less than 7000.

As the macromonomer, a general manufacturer (for example, a macromonomer manufactured by Toagosei Co., Ltd., etc.) can be used appropriately.

The high molecular weight skeleton component of the macromonomer preferably comprises an acrylic polymer or a vinyl polymer.

基酯、(甲基)丙烯酸2-苯氧基乙酯、丙烯酸3,5,5-三甲基環己酯、對異丙苯基苯酚EO改性(甲基)丙烯酸酯、(甲基)丙烯酸二環戊酯、(甲基)丙烯酸二環戊烯酯、(甲基)丙烯酸二環戊烯氧基乙酯、(甲基)丙烯酸苄酯、(甲基)丙烯酸羥基烷基酯、(甲基)丙烯酸、(甲基)丙烯酸縮水甘油酯、(甲基)丙烯醯胺、N,N-二甲基(甲基)丙烯醯胺、(甲基)丙烯腈、(甲基)丙烯酸烷氧基烷基酯、烷氧基聚伸烷基二醇(甲基)丙烯酸酯等(甲基)丙烯酸酯單體或苯乙烯、第三丁基苯乙烯、α-甲基苯乙烯、乙烯基甲苯、烷基乙烯基單體、乙酸乙烯酯、烷基乙烯基醚、羥基烷基乙烯基醚等各種乙烯基單體，該等可單獨使用或組合兩種以上使用。 Examples of the high-molecular-weight skeleton component of the macromonomer include: methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, (meth)acrylate base) n-butyl acrylate, isobutyl (meth)acrylate, second butyl (meth)acrylate, third butyl (meth)acrylate, amyl (meth)acrylate, isobutyl (meth)acrylate Pentyl, neopentyl (meth)acrylate, hexyl (meth)acrylate, cyclohexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, Isooctyl acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, tert-butylcyclohexyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate ester, undecyl (meth)acrylate, lauryl (meth)acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate , Behenyl (meth)acrylate, Iso(meth)acrylate

Base ester, 2-phenoxyethyl (meth)acrylate, 3,5,5-trimethylcyclohexyl acrylate, p-cumylphenol EO modified (meth)acrylate, (meth) Dicyclopentyl acrylate, Dicyclopentenyl (meth)acrylate, Dicyclopentenyloxyethyl (meth)acrylate, Benzyl (meth)acrylate, Hydroxyalkyl (meth)acrylate, ( Meth)acrylic acid, glycidyl (meth)acrylate, (meth)acrylamide, N,N-dimethyl(meth)acrylamide, (meth)acrylonitrile, (meth)acrylamide (meth)acrylate monomers such as oxyalkyl esters, alkoxy polyalkylene glycol (meth)acrylates, or styrene, tert-butylstyrene, α-methylstyrene, vinyl Various vinyl monomers such as toluene, alkyl vinyl monomers, vinyl acetate, alkyl vinyl ethers, and hydroxyalkyl vinyl ethers may be used alone or in combination of two or more.

As a terminal polymerizable functional group of the said macromonomer, a methacryl group, an acryl group, a vinyl group etc. are mentioned, for example.

(Crosslinking agent (1-B1))

As the crosslinking agent (1-B1), for example, one having two or more crosslinkable groups such as epoxy groups or isocyanate groups, oxetanyl groups, silanol groups, (meth)acryl groups, etc. crosslinking agent. Among them, in terms of reactivity or the strength of the obtained hardened product, polyamides having 2 or more (meth)acryl groups are preferred, and polyamides having 3 or more (meth)acryl groups are more preferred. A functional (meth)acrylate or a (meth)acrylate having an epoxy group, an isocyanate group, or the like.

After laminating and integrating the components of the image display device, the cross-linking agent (1-B1) is cross-linked in the adhesive material, so that the sheet loses its heat-meltability and is replaced by one that exhibits higher performance in high-temperature environments. Cohesion, to obtain excellent reliability against foaming.

Examples of such (meth)acrylates include 1,4-butanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, glycerin di(meth)acrylate, Glycerin glycidyl ether di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, tricyclodecane dimethanol di( Meth)acrylate, bisphenol A polyethoxy di(meth)acrylate, bisphenol A polyalkoxy di(meth)acrylate, bisphenol F polyalkoxy di(meth)acrylate , polyalkylene glycol di(meth)acrylate, trimethylolpropane trioxyethyl(meth)acrylate, ε-caprolactone modified tris(2-hydroxyethyl)isocyanurate ester tri(meth)acrylate, pentaerythritol tri(meth)acrylate, propoxylated pentaerythritol tri(meth)acrylate, ethoxylated pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, Propoxylated pentaerythritol tetra(meth)acrylate, ethoxylated pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, polyethylene glycol di(meth)acrylate, tris(acryloxy Ethyl) isocyanurate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate, tripentaerythritol hexa(meth)acrylate, tripentaerythritol Penta(meth)acrylate, hydroxypivalate neopentyl glycol di(meth)acrylate, di(meth)acrylate of ε-caprolactone adduct of hydroxypivalate neopentyl glycol , trimethylolpropane tri(meth)acrylate, alkoxylated trimethylolpropane tri(meth)acrylate, bis(trimethylolpropane)tetra(meth)acrylate, etc. Monomers, in addition, polyfunctional acrylic acid such as polyester (meth)acrylate, epoxy (meth)acrylate, (meth)acrylate urethane, polyether (meth)acrylate, etc. Ester oligomers or isocyanate (meth)acrylate, 1,1-(bis(meth)acryloxymethyl)ethyl isocyanate, 2-(2-(meth)acryloxy (ethyloxy) ethyl isocyanate, (meth) glycidyl acrylate, (meth) hydroxyethyl acrylate glycidyl ether, (meth) hydroxypropyl acrylate glycidyl ether, (meth) hydroxybutyl acrylate Ester glycidyl ether etc.

Among those listed above, polyfunctional monomers or oligomers containing polar functional groups such as hydroxyl groups are preferred from the viewpoint of improving the adhesion to the adherend or the effect of suppressing wet heat whitening.

Among them, it is preferable to use a polyfunctional (meth)acrylate having a hydroxyl group or a carboxyl group.

Therefore, from the viewpoint of preventing whitening under heat and humidity, it is preferable to contain a hydrophobic acrylate monomer and a hydrophilic acrylate monomer as the main component of the above-mentioned acrylic copolymer (1-A1), that is, a graft copolymer. Furthermore, it is preferable to use a polyfunctional (meth)acrylate which has a hydroxyl group as a crosslinking agent (1-B).

The content of the crosslinking agent (1-B1) is not particularly limited. As a standard, it is preferably 0.5 to 20 parts by mass relative to 100 parts by mass of the acrylic copolymer (1-A1), more preferably at least 1 part by mass and at most 15 parts by mass, and even more preferably at least 2 parts by mass Or a ratio of 10 parts by mass or less.

By containing the crosslinking agent (1-B1) within the above range, the shape stability of the adhesive sheet 1 in the uncrosslinked state and the foaming resistance reliability of the crosslinked adhesive can be simultaneously realized. Among them, in terms of balance with other elements, it may also exceed this range.

(Photopolymerization Initiator (1-C1))

The photopolymerization initiator (1-C1) functions as a reaction initiation aid for the crosslinking reaction of the above-mentioned crosslinking agent (1-B1).

As the photopolymerization initiator, conventionally known ones can be appropriately used. Among them, a photopolymerization initiator responsive to ultraviolet rays having a wavelength of 380 nm or less is preferable from the viewpoint of easy control of the crosslinking reaction.

On the other hand, a photopolymerization initiator that responds to light with a wavelength longer than 380 nm is preferable in that the induced light easily reaches the deep portion of the adhesive sheet 1 .

Photopolymerization initiators are roughly divided into two categories according to the mechanism of free radical generation, roughly divided into: cleavage-type photopolymerization initiators that can break and decompose the single bond of the photopolymerization initiator itself to generate free radicals, and The photoexcited initiator and the hydrogen donor and donor in the system form an excited complex, which can transfer the hydrogen of the hydrogen donor and donor to the hydrogen abstraction type photopolymerization initiator.

As the cleavage-type photopolymerization initiator among these, it decomposes into other compounds when free radicals are generated by light irradiation, and loses its function as a reaction initiator once it is excited. Therefore, it is preferable because it does not remain as an active material in the adhesive material after the crosslinking reaction is completed, and there is no possibility of causing unexpected photodegradation to the adhesive material.

On the other hand, when a hydrogen abstraction photopolymerization initiator is irradiated with active energy rays such as ultraviolet rays to generate a free radical reaction, no decomposition product such as a cracking photopolymerization initiator is generated, so it is difficult to become Volatile components can reduce the damage to the adherend and are more useful in this respect.

啉基苯基)丁烷-1-酮、2-甲基-1-[4-(甲硫基)苯基]-2-

啉基丙烷-1-酮、2-(二甲胺基)-2-[(4-甲基苯基)甲基]-1-[4-(4-

啉基)苯基]-1-丁酮、雙(2,4,6-三甲基苯甲醯基)-苯基氧化膦、2,4,6-三甲基苯甲醯基二苯基氧化膦或該等之衍生物等。 Examples of the cleavage-type photoinitiator include: 2,2-dimethoxy-1,2-diphenylethan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2 -Methyl-1-phenyl-propan-1-one, 1-(4-(2-hydroxyethoxy)phenyl)-2-hydroxy-2-methyl-1-propan-1-one, 2 -Hydroxy-1-[4-{4-(2-hydroxy-2-methyl-propionyl)benzyl}phenyl]-2-methyl-propan-1-one, oligo(2-hydroxy- 2-methyl-1-(4-(1-methylvinyl)phenyl)acetone), methyl phenylglyoxylate, 2-benzyl-2-dimethylamino-1-(4-

Linylphenyl) butane-1-one, 2-methyl-1-[4-(methylthio)phenyl]-2-

Linyl propan-1-one, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-

Phenyl)phenyl]-1-butanone, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenyl Phosphine oxide or their derivatives, etc.

、2-氯-9-氧硫

、3-甲基-9-氧硫

、2,4-二甲基-9-氧硫

、2-甲基蒽醌、2-乙基蒽醌、2-第三丁基蒽醌、2-胺基蒽醌或其衍生物等。 Examples of the hydrogen abstraction type photoinitiator include: benzophenone, 4-methyl-benzophenone, 2,4,6-trimethylbenzophenone, 4-phenylbenzophenone Ketone, 3,3'-dimethyl-4-methoxybenzophenone, 4-(meth)acryloxybenzophenone, methyl 2-benzoylbenzoate, benzoyl Methyl methanoate, bis(2-phenyl-2-glyoxylate)oxybisethylene, 4-(1,3-acryloyl-1,4,7,10,13-pentaoxotridecane base) benzophenone, 9-oxosulfur

, 2-Chloro-9-oxosulfur

, 3-methyl-9-oxosulfur

, 2,4-Dimethyl-9-oxosulfur

, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-aminoanthraquinone or its derivatives, etc.

However, it is not limited to what was listed above as a photoinitiator. Any of the cleavage type photopolymerization initiators and hydrogen abstraction type photopolymerization initiators listed above may be used, or two or more of them may be used in combination.

The content of the photopolymerization initiator (1-C1) is not particularly limited. As a standard, it is preferably 0.1 to 10 parts by mass relative to 100 parts by mass of the acrylic copolymer (1-A1), more preferably 0.5 parts by mass or more or less than 5 parts by mass, and even more preferably 1 part by mass More than or equal to 3 parts by mass or less.

Moderate reaction sensitivity to active energy rays can be obtained by making content of a photoinitiator (1-C1) into the said range.

(other ingredients)

The adhesive composition (1-I) may contain, as components other than the above, known components formulated in ordinary adhesive compositions. For example, if necessary, various types such as adhesion-imparting resins, antioxidants, photostabilizers, metal deactivators, anti-aging agents, moisture absorbers, polymerization inhibitors, ultraviolet absorbers, rust inhibitors, silane coupling agents, and inorganic particles can be appropriately contained. additive.

Moreover, a reaction catalyst (tertiary amine type compound, quaternary ammonium type compound, tin laurate compound, etc.) may be contained suitably as needed.

<Adhesive composition (1-II)>

Examples of the adhesive composition (1-II) include: Monomer a1 with a glass transition temperature (Tg) of 0°C or higher, monomer a2 with a glass transition temperature (Tg) of 80°C or higher and monomer a3 with a glass transition temperature (Tg) of 80°C or higher, a1:a2:a3= 10~40: 90~35: 0~25 molar ratio copolymerized (meth)acrylic acid ester copolymer or vinyl copolymer (meth)acrylic copolymer with a weight average molecular weight of 50000~400000 (1-A2); an adhesive composition of a crosslinking agent (1-B2) and a photopolymerization initiator (1-C2).

((meth)acrylic copolymer (1-A2))

The (meth)acrylic copolymer (1-A2) as the base polymer is preferably a (meth)acrylate copolymer or vinyl copolymer.

From the point of view of achieving both shape retention and heat-fusibility at room temperature, the weight average molecular weight of the (meth)acrylate copolymer or vinyl copolymer is preferably 50,000 to 500,000, more preferably 60,000 It is more than or equal to 450,000, and more preferably, it is more than or equal to 70,000 or less than 400,000.

For acrylate copolymers, the glass transition temperature (Tg) or properties such as molecular weight.

In this case, as an acrylic monomer which comprises an acrylate copolymer, 2-ethylhexyl acrylate, n-octyl acrylate, isooctyl acrylate, n-butyl acrylate, ethyl acrylate, etc. are mentioned as a main raw material, for example.

In addition to these, a (meth)acrylic monomer having various functional groups may be copolymerized with the above-mentioned acrylic monomer for the purpose of imparting cohesive force, imparting polarity, or the like.

Examples of the (meth)acrylic monomer having a functional group include methyl methacrylate, methyl acrylate, hydroxyethyl acrylate, acrylic acid, glycidyl acrylate, N-substituted acrylamide, acrylonitrile, Methacrylonitrile, fluorine-containing alkyl acrylate, organosilicon alkoxy Acrylic etc.

On the other hand, examples of vinyl copolymers include various vinyl copolymers such as vinyl acetate, alkyl vinyl ether, and hydroxyalkyl vinyl ether, which can be copolymerized with the above-mentioned acrylic monomer or methacrylic monomer. Monomers are also suitable for polymerization of vinyl copolymers.

The (meth)acrylic copolymer (1-A2) of this adhesive sheet 1 is preferably a monomer a1 whose glass transition temperature (Tg) does not reach 0°C, and whose glass transition temperature (Tg) is 0°C or higher And the monomer a2 which is less than 80°C and the monomer a3 whose glass transition temperature (Tg) is above 80°C are copolymerized at a molar ratio of a1:a2:a3=10~40:90~35:0~25 into (meth)acrylate copolymers or vinyl copolymers.

At this time, the respective glass transition temperatures (Tg) of the monomers a1, a2, and a3 are obtained from the respective glass transition temperatures (Tg) when the monomers are produced into polymers (homopolymerization).

The above-mentioned monomer a1 is preferably, for example, a (meth)acrylate monomer having an alkyl structure having a side chain having 4 or more carbon atoms.

In this case, the side chain having 4 or more carbon atoms may include a straight chain or a branched carbon chain.

More specifically, the above-mentioned monomer a1 is preferably a (meth)acrylate monomer having a linear alkyl structure with 4 to 10 carbons or a (meth)acrylate monomer having a branched alkyl structure with 6 to 18 carbons. ) acrylate monomer.

Here, examples of the "(meth)acrylate monomer having a linear alkyl structure having 4 to 10 carbon atoms" include n-butyl acrylate, n-hexyl acrylate, n-octyl acrylate, n-nonyl acrylate, N-decyl acrylate, etc.

On the other hand, examples of "(meth)acrylate monomers having a branched chain alkyl structure having 6 to 18 carbon atoms" include 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, Acrylic 2- Methylhexyl, isooctyl acrylate, isononyl acrylate, isodecyl acrylate, isodecyl methacrylate, etc.

The above-mentioned monomer a2 is preferably a (meth)acrylate monomer with 4 or less carbon atoms, a (meth)acrylate monomer with a ring skeleton in the side chain, a vinyl monomer with 4 or less carbon atoms, or a vinyl monomer with a carbon number of 4 or less. Vinyl monomer with ring skeleton.

Among them, the above-mentioned monomer a2 is particularly preferably a vinyl monomer having 4 or less carbon atoms in the side chain.

Here, examples of the "(meth)acrylate monomer having 4 or less carbon atoms" include methyl acrylate, ethyl methacrylate, n-propyl acrylate, n-propyl methacrylate, isopropyl acrylate, Isopropyl methacrylate, n-butyl methacrylate, tert-butyl acrylate, isobutyl acrylate, isobutyl methacrylate, etc.

基酯、丙烯酸環己酯、甲基丙烯酸環己酯、1,4-環己烷二甲醇單丙烯酸酯、甲基丙烯酸四氫糠酯、丙烯酸苄酯、甲基丙烯酸苄酯、丙烯酸苯氧基乙酯、甲基丙烯酸苯氧基乙酯、丙烯酸2-羥基-3-苯氧基丙酯、3,3,5-三甲基環己醇丙烯酸酯、環狀三羥甲基丙烷甲縮醛丙烯酸酯、4-乙氧化異丙苯基苯酚丙烯酸酯、丙烯酸二環戊烯氧基乙酯、甲基丙烯酸二環戊烯氧基乙酯、丙烯酸二環戊烯酯等。 Examples of the "(meth)acrylate monomer having a cyclic skeleton in the side chain" include:

methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, 1,4-cyclohexanedimethanol monoacrylate, tetrahydrofurfuryl methacrylate, benzyl acrylate, benzyl methacrylate, phenoxy acrylate Ethyl ester, phenoxyethyl methacrylate, 2-hydroxy-3-phenoxypropyl acrylate, 3,3,5-trimethylcyclohexanol acrylate, cyclic trimethylolpropane formal Acrylates, 4-ethoxylated cumylphenol acrylate, dicyclopentenyloxyethyl acrylate, dicyclopentenyloxyethyl methacrylate, dicyclopentenyl acrylate, and the like.

Examples of "vinyl monomers having 4 or less carbon atoms" include: vinyl acetate, vinyl propionate, vinyl butyrate, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, vinyl ether etc.

基乙烯醚、降

烯基乙烯醚等。其中，尤佳為側鏈之碳數為4以下之乙烯基單體或側鏈之碳數為4以下之丙烯酸酯單體。 Examples of the "vinyl monomer having a cyclic skeleton in the side chain" include styrene, cyclohexyl vinyl ether, nor

Vinyl ether, nor

Alkenyl vinyl ether, etc. Among them, a vinyl monomer having 4 or less carbon atoms in the side chain or an acrylate monomer having 4 or less carbon atoms in the side chain is particularly preferable.

The above-mentioned monomer a3 is preferably a (meth)acrylate monomer having 1 or less carbon atoms in the side chain or a (meth)acrylate monomer having a cyclic skeleton in the side chain.

Here, examples of the "(meth)acrylate monomer having one or less carbon atoms in the side chain" include methyl methacrylate, acrylic acid, methacrylic acid, and the like.

基酯、甲基丙烯酸3,3,5-三甲基環己酯、丙烯酸二環戊酯、甲基丙烯酸二環戊酯、甲基丙烯酸二環戊烯酯等。 Examples of the "(meth)acrylate monomer having a cyclic skeleton in the side chain" include:

Base ester, 3,3,5-trimethylcyclohexyl methacrylate, dicyclopentyl acrylate, dicyclopentanyl methacrylate, dicyclopentenyl methacrylate, etc.

If the (meth)acrylic copolymer (1-A2) contains monomer a1, monomer a2 and monomer a3 in a molar ratio of a1:a2:a3=10~40:90~35:0~25 The polymerized (meth)acrylate copolymer or ethylene-based copolymer can adjust the peak of Tanδ to 0~20°C, and can maintain the shape of a sheet in the normal state, that is, at room temperature. Also, it has the property of sticking to the adherend with light force for a short time (called "adhesive"). In addition, when heated to a heat-melting temperature, it exhibits fluidity and can be filled to every corner following the step of the bonding surface.

Therefore, from this point of view, the difference between monomer a1, monomer a2 and monomer a3 in the (meth)acrylate copolymer or vinyl copolymer constituting the (meth)acrylic copolymer (1-A2) The molar ratio is preferably a1:a2:a3=10~40:90~35:0~25, more preferably 13~40:87~35:0~23, and more preferably 15~40:85 ~38:2~20.

Also, from the same viewpoint as above, monomer a1, monomer a2 and monomer The molar ratio of body a3 is preferably a2>a1>a3.

(Crosslinking agent (1-B2))

By crosslinking the crosslinking agent (1-B2) in the adhesive sheet 1, the adhesive sheet 1 exhibits high cohesive force under high temperature environment, and can obtain excellent reliability against foaming.

As such a crosslinking agent (1-B2), for example, crosslinking properties such as epoxy groups or isocyanate groups, oxetanyl groups, silanol groups, (meth)acryl groups, etc. can be appropriately selected. base crosslinking agent. Among them, in terms of reactivity or the strength of the obtained hardened product, polyamides having 2 or more (meth)acryl groups are preferred, and polyamides having 3 or more (meth)acryl groups are more preferred. Functional (meth)acrylates or (meth)acrylates having epoxy groups, isocyanate groups, etc.

Examples of such (meth)acrylates include 1,4-butanediol di(meth)acrylate, glycerin di(meth)acrylate, 1,6-hexanediol di(methyl) Acrylates, 1,9-nonanediol di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, bisphenol A polyethoxy di(meth)acrylate, bisphenol A Polypropoxy di(meth)acrylate, bisphenol F polyethoxy di(meth)acrylate, ethylene glycol di(meth)acrylate, trimethylolpropane trioxyethyl(methyl) ) acrylate, ε-caprolactone modified tris(2-hydroxyethyl)isocyanurate tri(meth)acrylate, pentaerythritol tri(meth)acrylate, propoxylated pentaerythritol tri(meth)acrylate ester, ethoxylated pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, propoxylated pentaerythritol tetra(meth)acrylate, ethoxylated pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate ) acrylate, polyethylene glycol di(meth)acrylate, tris(acryloxyethyl)isocyanurate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, Dipentaerythritol penta(meth)acrylate, tripentaerythritol hexa(meth)acrylate, tripentaerythritol penta(meth)acrylate, hydroxypivalic acid neopentyl glycol di(meth)acrylate, hydroxypivalic acid Di(meth)acrylate of ε-caprolactone adduct of neopentyl glycol ester, trimethylolpropane tri(meth)acrylate, trimethylolpropane polyethoxytri(meth)acrylate Acrylate, bis(trimethylolpropane)tetra(meth)acrylate and other ultraviolet curable polyfunctional monomers, and also polyester (meth)acrylate, epoxy (meth)acrylate , (meth)acrylate urethane, polyether (meth)acrylate and other multifunctional acrylate oligomers or isocyanate (meth)acrylic enoate, 1,1-(bis(meth)acryloxymethyl)ethyl isocyanate, 2-(2-(meth)acryloxyethyloxy)ethyl isocyanate, (methyl ) glycidyl acrylate, (meth)hydroxyethyl acrylate glycidyl ether, (meth)hydroxypropyl acrylate glycidyl ether, (meth)hydroxybutyl acrylate glycidyl ether, etc.

Among those listed above, from the viewpoint of improving the adhesiveness to the adherend, the heat resistance, and the effect of suppressing wet heat whitening, polyfunctional monomers or oligomers containing polar functional groups are preferred. Among them, it is preferable to use a polyfunctional (meth)acrylate having an isocyanuric acid ring skeleton.

The content of the crosslinking agent (1-B2) is not particularly limited. As a standard, it is preferably 0.5 to 20 parts by mass with respect to 100 parts by mass of the (meth)acrylic copolymer (1-A2), more preferably 1 part by mass or more and 15 parts by mass or less, and even more preferably 0.5 to 20 parts by mass The ratio of 2 mass parts or more or 10 mass parts or less.

By containing the crosslinking agent (1-B2) within the above range, the shape stability of the adhesive sheet 1 in the uncrosslinked state and the foaming resistance reliability of the crosslinked adhesive can be simultaneously realized. Among them, in terms of balance with other elements, it may also exceed this range.

(Photopolymerization Initiator (1-C2))

The photopolymerization initiator (1-C2) functions as a reaction initiation aid for the crosslinking reaction of the above-mentioned crosslinking agent (1-B2), and the above-mentioned photopolymerization initiator (1-C1) can be used appropriately recorded.

The content of the photopolymerization initiator (1-C2) is not particularly limited. As a standard, it is preferably 0.1 to 10 parts by mass relative to 100 parts by mass of the (meth)acrylic copolymer (1-A2), more preferably at least 0.5 parts by mass or less than 5 parts by mass, and even more preferably It is contained in the ratio of 1 mass part or more or 3 mass parts or less.

Moderate reaction sensitivity to active energy rays can be obtained by making content of a photoinitiator (1-C2) into the said range.

(other ingredients)

The adhesive composition (1-II) may contain, as components other than the above, known components formulated in ordinary adhesive compositions. For example, if necessary, various types such as adhesion-imparting resins, antioxidants, photostabilizers, metal deactivators, anti-aging agents, moisture absorbers, polymerization inhibitors, ultraviolet absorbers, rust inhibitors, silane coupling agents, and inorganic particles can be appropriately contained. additive.

Moreover, a reaction catalyst (tertiary amine type compound, quaternary ammonium type compound, tin laurate compound, etc.) may be contained suitably as needed.

<Laminated structure>

The adhesive sheet 1 may be a sheet comprising a single layer, or may be a multilayer sheet formed by laminating two or more layers.

When the adhesive sheet 1 is a multi-layer adhesive sheet, it only needs to have an adhesive layer formed from the adhesive composition 1 (referred to as "the adhesive layer 1"), for example, when forming a layer having an intermediate layer and an outermost layer In the case of an adhesive sheet having a laminated structure, it is preferable to form the outermost layer from the present adhesive composition 1, and it is more preferable to form the outermost layer from the adhesive composition (1-I) (1-II).

In addition, the present adhesive sheet 1 may be provided with a structure in which the present adhesive layer 1 formed from the present adhesive composition 1 is formed on a release film, and may be provided on an adherend such as the following A structure in which the above-mentioned adhesive layer 1 is formed on a constituent member for an image display device. Also, for example, it may be a base-attached adhesive sheet having a structure in which the above-mentioned present adhesive layer 1 is formed on a base material, or may be a base-less adhesive sheet not having a base material. Furthermore, it may be a double-sided adhesive sheet having the present adhesive layer 1 on both upper and lower sides, or a single-sided adhesive sheet having the present adhesive layer 1 only on the upper and lower sides.

<thickness>

As the thickness of the adhesive sheet 1, it is determined not to hinder the thinning of the image display device. In other words, the thickness of the maximum thickness portion is preferably 250 μm or less. In other words, the adhesive sheet 1 may be a sheet with a uniform thickness, or a non-uniform sheet with parts having different thicknesses. In the case of a sheet with non-uniform thickness, the thickness of the thickest part is preferably 250 μm or less .

Also, the thickness of the maximum thickness portion is preferably at least 5 μm, more preferably at least 10 μm, and still more preferably at least 15 μm, from the viewpoint of not hindering the adhesion with the adherend or shock absorption.

<purpose>

This adhesive sheet 1 can be used in its original form, and can also be used in the following manner. However, the utilization method of the adhesive sheet 1 is not limited.

This adhesive sheet 1 can be provided, for example as an adhesive sheet laminate including a release film on one side of this adhesive sheet 1 or a double-sided layer.

<Laminate 1 for constituting the present image display device>

In addition, a laminated body for constituting an image display device (hereinafter referred to as "this image display device") having a structure in which two constituting members for an image display device are laminated via this adhesive sheet 1 can be produced and provided. Laminated body for constituting 1").

The laminate 1 for constituting an image display device can be produced, for example, by interposing the above-mentioned adhesive sheet 1 to laminate the constituent members for an image display device and other constituent members for an image display device, and interposing the image of the former The display device constituting members irradiate the above-mentioned adhesive sheet 1 with light to photocure the adhesive sheet.

As an example of the laminate 1 for constituting the image display device, in addition to the laminate including the protective panel/this adhesive sheet 1/polarizing film, for example, image display panel/this adhesive sheet 1/touch Control panel, image display panel/this adhesive sheet 1/protective panel, image display panel/this adhesive sheet 1/touch panel/this adhesive sheet 1/protective panel, polarizing film/this adhesive sheet 1/ touch Control panel, polarizing film/adhesive sheet 1/touch panel/adhesive sheet 1/protective panel.

The protection panel and the image display panel may also be those in which a touch panel sensor is incorporated in the protection panel or the image display panel itself.

<This image display device 1>

An image display device (hereinafter referred to as "the present image display device 1") can also be configured using the adhesive sheet 1 or the laminate for constituting the image display device.

An example of a preferable manufacturing method of the present image display device 1 will be described.

First, the above-mentioned adhesive sheet 1 is heated to be thermally fused, and the constituent members for an image display device and other constituent members for an image display device are laminated with the adhesive sheet 1 interposed therebetween. At this stage, since the present adhesive sheet 1 is moderately soft, it can sufficiently follow a step difference while maintaining storage stability.

Then, light such as ultraviolet rays is irradiated from the outside of the constituent member for an image display device. As a result, cross-linking reaction can be carried out to make it photocurable, and excellent peeling resistance and foaming resistance can be realized.

As the constituent members for the above two image display devices, for example, computer, mobile terminal (PDA), game machine, television (TV), car navigation, touch panel, tablet and other LCD, PDP or EL etc. Components of display devices. More specifically, for example, any one of the group consisting of a touch panel, an image display panel, a surface protection panel, and a polarizing film, or a laminate including a combination of two or more thereof can be used.

[this adhesive sheet 2]

An adhesive sheet (referred to as "the present adhesive sheet 2"), which is an example of another embodiment of the present invention, is an adhesive sheet that contains a (meth)acrylic copolymer (A) as a base polymer and is partially photocured material, and any one of the adhesive sheets has a sheet part with a gel fraction of less than 1% (called "soft part") and a sheet part with a gel fraction of 40% or more (called "hard part") ").

As a method for measuring the gel fraction, extraction with a solvent is exemplified. Specifically, when the polymer constituting the adhesive sheet is not cross-linked, a solvent (good solvent) that dissolves the polymer is selected, and then, the adhesive sheet is extracted using the solvent. As a solvent at the time of extraction, ethyl acetate, acetone, toluene, xylene, lower alcohol, tetrahydrofuran etc. are mentioned, for example.

The temperature or time during extraction can be set arbitrarily. After the extraction operation, recover the insoluble component (swelling component) in the solvent, dry it, and measure the weight fraction. As a specific extraction method, Soxhlet extraction or the method described in the following examples etc. are mentioned.

Furthermore, when the gel fraction is relatively high, it may be appropriate to crush the adhesive sheet for extraction.

For example, in the display screen of a mobile phone, a liquid crystal panel display (LCD) is laminated with a polarizing film, etc., and a protective panel made of adhesive or sheet-laminated plastic is interposed thereon, usually on the back of the protective panel. The peripheral part is provided with opaque parts such as printing parts.

When the protective panel with the printing part is bonded to other components of the image display device such as the touch panel through the adhesive sheet, if the adhesive sheet can follow the printing steps and fill to every corner, Moreover, if the surface of the adhesive sheet is not smooth, strain or deformation will occur in the adhesive sheet when the image display components are pasted, which will cause the decrease in visibility caused by uneven display. Therefore, the adhesive sheet is required to have flexibility. . In addition, there is a problem that strain and deformation are likely to occur in the adhesive sheet due to printing steps and the like.

On the other hand, it is required that the exposed adhesive surface is not sticky even in severe environments such as high temperature and high humidity. Not only that, it is also required that the adhesive sheet bonded to the components of the image display device through the adhesive sheet has a high cohesive force without peeling or foaming.

Therefore, the present invention intends to provide a step difference portion even when it is bonded to a constituent member for an image display device having an opaque portion such as a printed portion and a light-transmitting portion in the bonding surface, for example. The followability or flatness of the surface will not produce strain or deformation in the opaque part, and it can have high cohesion to firmly bond the adherends to each other, and even under high temperature and high humidity Novel adhesive sheet 2 that can also make the exposed adhesive surface not sticky under harsh environments.

In this adhesive sheet 2, the soft part with a gel fraction of less than 1% can obtain followability or surface flatness to the step part, etc., and can relieve strain or deformation in the sheet. On the other hand, With the hard part with a gel fraction of 40% or more, not only can the adhesive surface not be sticky, but it can also have a high cohesive force so that the adherends can be firmly bonded to each other.

Therefore, for example, even in the case of bonding to a constituent member for an image display device having an opaque portion such as a printed portion and a light-transmitting portion in the bonding surface, it is possible to obtain a print level difference as a whole of the adhesive sheet. The followability or surface flatness of the part does not cause strain or deformation in the opaque part, and furthermore, it can have a high cohesive force to firmly bond the adherends to each other. Also, by using the exposed adhesive surface as a hard portion, the exposed adhesive surface can be kept from sticking even under severe environments such as high temperature and high humidity.

The adhesive sheet 2 can be, for example, as shown in Figure 1 or Figure 2, with the above-mentioned soft part and hard part in the sheet surface of the adhesive sheet, and can also be as shown in Figure 3 (A) (B). Or as shown in FIG. 5 , at least one end surface of the adhesive sheet has the form of the above-mentioned hard portion. In this case, the sheet surface of the adhesive sheet may be a soft part or a hard part. Moreover, as shown in FIG. 5, the said hard part may be provided in the end surface part of at least one side of the roll-shaped adhesive sheet.

The "base polymer" in the present invention refers to a resin that becomes the main component of the adhesive composition forming each layer. The specific content of the base polymer is not specified, but as a standard, it is preferably at least 50% by mass of the resin contained in the adhesive composition forming each layer, more preferably at least 80% by mass, and even more preferably at least 90% by mass. Resin of mass % or more (including 100 mass %). Furthermore, when there are two or more base polymers, the total amount thereof is the above-mentioned content.

From the standpoint of followability of the step portion, surface flatness, and relaxation of strain or deformation in the sheet, the gel fraction of the soft portion is preferably less than 1%, and more preferably less than 1%. 0.8%, of which the best is less than 0.5%.

On the other hand, the gel fraction of the above-mentioned hard part is preferable from the viewpoint of exerting a higher cohesive force to improve adhesiveness, and not making the adhesive surface sticky even in severe environments such as high temperature and high humidity. More than 40%, more preferably more than 45%, and especially more than 50%.

In addition, if the glass transition temperature (Tg[S]) of the above-mentioned soft part measured by using a differential scanning calorimeter (DSC) is -70~-10°C, it has moderate flexibility and self-adhesiveness in the normal temperature range, so The Tg of the soft part is preferably -70~-10°C, more preferably above -65°C or below -15°C, especially preferably above -60°C or below -20°C.

On the other hand, if the glass transition temperature (Tg[H]) of the above-mentioned hard part measured by using a differential scanning calorimeter (DSC) is -60~+10°C, a higher cohesive force can be obtained, so the hard part Tg is preferably -60 to +20°C, more preferably above -55°C or below +15°C, especially preferably above -50°C or below +10°C.

In addition, if the difference (Tg[H]-Tg[S]) between the glass transition temperature (Tg[S]) of the soft part and the glass transition temperature (Tg[H]) of the hard part is 3 °C or more, it can be higher The level achieves the opposite qualities of softness and cohesive force at the same time. As a result, it can simultaneously realize the followability of the adhered surface during lamination and the excellent foaming resistance reliability of the laminated body, so it is preferable. Therefore, the difference (Tg[H]-Tg[S]) of the glass transition temperature (Tg[H]) of the hard portion is preferably 3°C or higher, more preferably 5°C or higher, and particularly preferably 7°C or higher.

(Asker hardness of the soft part)

Since the Ascal hardness (c) of the soft part of this adhesive sheet 2 is 10 or more, moderate hardness can be obtained with respect to the easiness of cutting processability and handling, and it is preferable. Also, by making the above The Ska hardness (c) is less than 60, which can obtain moderate flexibility and adhesion to the adherend, so it is preferable.

From this point of view, the Ascal hardness (c) of the soft part of the adhesive sheet 2 is preferably 10 or more and less than 60, more preferably 15 or more or 55 or less, especially preferably 20 or more or 50 the following.

(Ascal hardness of the hard part)

By setting the Asker's hardness (d) of the hard portion of the adhesive sheet 2 to 40 or more, a high cohesive force can be obtained, and a laminate excellent in shape stability and foaming resistance reliability can be obtained. Moreover, since the laminated body excellent in impact resistance can be obtained without becoming too brittle by making the above-mentioned Ascal hardness (d) less than 90, it is preferable.

From this point of view, the Ascal hardness (d) of the hard portion of the adhesive sheet 2 is preferably 40 or more and less than 90, preferably 43 or more or 88 or less, and particularly preferably 45 or more or 85 or less. the following.

Furthermore, in this adhesive sheet 2, by setting the above-mentioned (d)-(c) to be 20 or more, it is possible to achieve both followability to the surface to be adhered during lamination and excellent foaming resistance reliability after the laminate, Therefore better.

From this point of view, in this adhesive sheet 2, the difference ((d)-(c)) between the Asker's hardness (c) of the soft part and the Asker's hardness (d) of the hard part is preferably 20. or more, more preferably 20 or more or 80 or less, especially preferably 25 or more or 75 or less.

In this adhesive sheet 2, in order to adjust the Asker's hardness (c) of the soft part and the Asker's hardness (d) of the hard part, the composition of the crosslinking agent or photopolymerization initiator is adjusted in the composition or manufacturing method ratio, or adjust the amount of light exposure to the adhesive composition. However, it is not limited to this method.

(180°peel force of the soft part)

By making the 180° peeling force of the soft portion of the adhesive sheet 2 3 N/cm or more, it can have a constant Moderate adhesion to the adherend at low temperature and excellent lamination workability, so it is better.

From this point of view, the 180° peel force of the soft portion of the adhesive sheet 2 is preferably 3 N/cm or more, preferably 20 N/cm or less, and particularly preferably 4 N/cm or more or 15 N/cm or less.

(180°peel force of hard part)

Since the 180° peeling force of the hard portion of the present adhesive sheet 2 is 5 N/cm or more, excellent foaming resistance and peeling properties can be obtained, which is preferable.

From this point of view, the 180° peel force of the hard portion of the adhesive sheet 2 is preferably 5 N/cm or more, preferably 25 N/cm or less, and particularly preferably 6 N/cm or more or 20 N/cm or less.

In this adhesive sheet 2, in order to adjust the 180° peeling force of the soft part and the hard part, in the composition or manufacturing method, the type or composition ratio of the crosslinking agent or photopolymerization initiator is adjusted, or the heating during lamination is adjusted. , pressurized conditions or light irradiation conditions after bonding. However, it is not limited to this method.

(40°C holding power of the soft part)

By making the holding force of the soft portion of the present adhesive sheet 2 at a temperature of 40° C. such that the offset length does not reach 10 mm, excellent processability and storage stability can be obtained.

From this point of view, the retention force of the soft portion of the present adhesive sheet 2 at a temperature of 40° C. is preferably less than 10 mm, more preferably less than 8 mm, and still more preferably less than 5 mm.

(70°C holding power of the soft part)

Also, regarding the holding power of the soft part of the present adhesive sheet 2 at a temperature of 70°C, if the sticking surface deviates and the weight falls within 10 minutes, then excellent adhesion to the adherend can be obtained during sticking or Bump absorbency, so better.

From this point of view, the holding power of the soft part of the adhesive sheet 2 at a temperature of 70°C is preferably less than 10 minutes when the sticking surface shifts and the weight falls, and more preferably less than 8 minutes. face to face Offset and the weight falls, and it is further preferably less than 6 minutes to face-to-face offset and the weight to drop.

(40℃ or 70℃ holding force of hard part)

The retention force of the hard portion of the adhesive sheet 2 at temperatures of 40°C and 70°C is preferably less than 1 mm in offset length, more preferably less than 0.7 mm, and still more preferably less than 0.5 mm.

By setting the holding power of the hard part of the adhesive sheet 2 at temperatures of 40° C. and 70° C. within the above-mentioned ranges, a high cohesive force can be obtained, and shape stability and foaming resistance reliability in hot and humid environments can be obtained.

<How to make this adhesive sheet 2>

This adhesive sheet 2 can be produced as follows.

(1) For the photocurable adhesive sheet, the part that will become the soft part is covered with a light-impermeable member, that is, a member that does not pass through light for photohardening, and the light is irradiated, so that the part can be covered with a light-impermeable member The part becomes the soft part, and the part not covered with the opaque member, that is, the part irradiated with light, is photohardened to become the hard part.

(2) Also, if light is irradiated to the end surface of the adhesive sheet and no light is irradiated to the portion other than the end surface, the end surface can be made into a hard portion and the other portions can be made into a soft portion.

For example, light can be irradiated on the end surface of the adhesive sheet (the front and back of the sheet are arranged vertically and vertically) from a vertical direction, a horizontal direction, or an inclined up and down direction, and the front and back of the adhesive sheet can also be illuminated together On one side or both sides, pre-laminated sheets for light hardening that do not pass through the light, and irradiate light from vertical or horizontal directions or obliquely up and down directions. By irradiating light in this way, the end surface of the adhesive sheet can be photohardened. At this time, as the above-mentioned light-proof sheet for photocuring, it is particularly preferable to use a release sheet based on polyethylene terephthalate; or to use polyethylene terephthalate UV absorber kneaded into ester film or polyolefin film, or release sheet of film coated with UV absorber on the surface, etc., used for light-proof release sheet for light hardening.

In addition, when light is irradiated, the end face part and its peripheral part can become a hard part.

(3) Also, the soft part and the hard part can be formed in the adhesive sheet by prefabricating the adhesive sheets each having a desired gel fraction and integrating the two.

<Adhesive sheet X>

The present adhesive sheet 2 can be formed by partially photocuring the following adhesive sheet X. However, it is not limited to use the following adhesive sheet X to form the present adhesive sheet 2 .

From the point of view of expressing hot-melt properties in the state before photohardening, the gel fraction (a) of the adhesive sheet X before photohardening is less than 1%, preferably less than 0.8%. Preferably it is less than 0.5%.

Also, from the standpoint of obtaining higher cohesive force after photocuring and the reliability of foaming resistance in hot and humid environments, the gel fraction (b) of the adhesive sheet X after photocuring is preferably More than 40%, more preferably more than 45% or less than 95%, especially more than 50% or less than 90%.

In order to adjust the gel fraction (a) before photohardening and the gel fraction (b) after photohardening as described above, adjust the composition ratio of the crosslinking agent or photopolymerization initiator in the composition or manufacturing method, or Just adjust the temperature or light exposure during processing. However, it is not limited to this method.

<This adhesive composition 2>

A resin composition (hereinafter, referred to as "this adhesive composition 2") that can be preferably used to form the above-mentioned adhesive sheet X will be described. However, it is only an example and is not limited thereto.

As this adhesive composition 2, a photocurable adhesive composition is preferable. Among them, a resin composition containing a (meth)acrylic copolymer (2-A), a crosslinking agent (2-B) and a photopolymerization initiator (2-C) is preferable.

However, as mentioned above, the composition of the adhesive composition for forming the adhesive sheet 2 is not limited as long as the gel fraction after adhesion can be varied depending on the location in the adhesive sheet.

Here, the present adhesive sheet 2 is particularly preferably an adhesive sheet that can maintain a sheet shape under normal conditions, has hot melt properties that melt or flow when heated in an uncrosslinked state, and has photocurable adhesive sheet that can be photocured. material.

If the sheet can be kept in a normal state, it is easier to handle than a liquid adhesive, and the work of filling the liquid can be omitted, so the productivity is particularly excellent.

Furthermore, if it has moderate adhesiveness in the normal state, that is, around room temperature, that is, the property of sticking to the adherend with a relatively light force for a short time (called "stickiness"), it is easy to position when sticking, It is excellent in workability, so it is preferable to have viscosity in the normal state, that is, around room temperature, and it is better if it also has viscosity in the lower temperature range from -5°C to 20°C.

In addition, since it has a hot-melt property that melts or flows when heated, it can be softened or fluidized by heating, and the adhesive can be filled with uneven parts such as printing steps, so it can be filled without foaming, etc. .

Furthermore, if it has photocurability, it can stick firmly by finally photocuring it.

In this way, in order to make a photocurable adhesive sheet that can maintain a sheet shape under normal conditions, has a heat-melt property that melts or flows when heated in an uncrosslinked state, for example, if it is a single-layer adhesive sheet, Then, it is only necessary to produce a single-layer adhesive sheet from the adhesive composition (2-I) or (2-II) described below. On the other hand, in the case of making a multilayer adhesive sheet, for example, an adhesive layer containing the adhesive composition (2-I) or (2-II) and an adhesive layer containing another adhesive composition can be mentioned. Two kinds of two-layer structures formed by lamination, or two kinds of three-layer structures in which an adhesive layer comprising the adhesive composition (2-I) or (2-II) is arranged on the front and back through an intermediate resin layer, or sequentially Three types of three-layer structures such as a laminate including an adhesive layer of the adhesive composition (2-I) or (2-II), an intermediate layer including an intermediate resin composition, and an adhesive layer including another adhesive composition.

Wherein, the adhesive composition used to form the adhesive sheet 2 is not limited to the adhesive combination Object (2-I) or (2-II).

<Adhesive composition (2-I)>

Examples of the adhesive composition (2-I) include: an acrylic copolymer (2-A1) comprising a graft copolymer having a macromonomer as a branch component, a crosslinking agent (2-B1), and a photopolymerization agent (2-B1). The resin composition of the initiator (2-C1).

(Acrylic Copolymer (2-A1))

The acrylic copolymer (2-A1) as the base polymer may be a graft copolymer having a macromonomer as a branch component.

(main ingredient)

It is preferable that the backbone component of the said acrylic-type copolymer (2-A1) contains the copolymer component containing the repeating unit derived from (meth)acrylate.

The glass transition temperature of the copolymer constituting the main component of the acrylic copolymer (2-A1) is preferably -70 to 0°C.

In this case, the glass transition temperature of the copolymer component constituting the main component refers to the glass transition temperature of a polymer obtained by copolymerizing only the monomer components constituting the main component of the acrylic copolymer (2-A1). Specifically, it refers to the value calculated by Fox's calculation formula from the glass transition temperature and composition ratio of the polymer obtained from the homopolymer of the respective components of the copolymer.

In addition, the calculation formula of Fox means the calculated value obtained by the following formula, and can be obtained using the value described in the polymer handbook [Polymer Handbook, J. Brandrup, Interscience, 1989].

1/(273+Tg)=Σ(Wi/(273+Tgi))

[Where, Wi represents the weight fraction of monomer i, and Tgi represents the Tg (°C) of the homopolymer of monomer i]

Glass transition of the copolymer component constituting the main component of the above-mentioned acrylic copolymer (2-A1) The temperature change will affect the flexibility of the adhesive composition (2-I) at room temperature, or the wettability of the adhesive composition (2-I) to the adherend, that is, the adhesiveness. Adhesive composition (2-I) obtains moderate adhesiveness (viscosity) at room temperature, and the glass transition temperature is preferably -70°C~0°C, more preferably -65°C or above or -5°C below, especially preferably above -60°C or below -10°C.

Among them, even if the glass transition temperature of the copolymer components is the same temperature, the viscoelasticity can be adjusted by adjusting the molecular weight. For example, by reducing the molecular weight of the copolymer component, it can be made more flexible.

基酯、(甲基)丙烯酸2-苯氧基乙酯、丙烯酸3,5,5-三甲基環己酯、對異丙苯基苯酚EO改性(甲基)丙烯酸酯、(甲基)丙烯酸二環戊酯、(甲基)丙烯酸二環戊烯酯、(甲基)丙烯酸二環戊烯氧基乙酯、(甲基)丙烯酸苄酯等。亦可使用該等中具有親水基或有機官能基等之(甲基)丙烯酸羥乙酯、(甲基)丙烯酸羥丙酯、(甲基)丙烯酸羥丁酯、(甲基)丙烯酸甘油酯 等含羥基之(甲基)丙烯酸酯，或(甲基)丙烯酸、2-(甲基)丙烯醯氧基乙基六氫鄰苯二甲酸、2-(甲基)丙烯醯氧基丙基六氫鄰苯二甲酸、2-(甲基)丙烯醯氧基乙基鄰苯二甲酸、2-(甲基)丙烯醯氧基丙基鄰苯二甲酸、2-(甲基)丙烯醯氧基乙基順丁烯二酸、2-(甲基)丙烯醯氧基丙基順丁烯二酸、2-(甲基)丙烯醯氧基乙基琥珀酸、2-(甲基)丙烯醯氧基丙基琥珀酸、丁烯酸、反丁烯二酸、順丁烯二酸、伊康酸、順丁烯二酸單甲酯、伊康酸單甲酯等含羧基之單體，順丁烯二酸酐、伊康酸酐等含酸酐基之單體，(甲基)丙烯酸縮水甘油酯、α-乙基丙烯酸縮水甘油酯、(甲基)丙烯酸3,4-環氧丁酯等含環氧基之單體，(甲基)丙烯酸二甲胺基乙酯、(甲基)丙烯酸二乙胺基乙酯等含胺基之(甲基)丙烯酸酯系單體，(甲基)丙烯醯胺、N-第三丁基(甲基)丙烯醯胺、N-羥甲基(甲基)丙烯醯胺、N-甲氧基甲基(甲基)丙烯醯胺、N-丁氧基甲基(甲基)丙烯醯胺、二丙酮丙烯醯胺、順丁烯二醯胺、順丁烯二醯亞胺等含醯胺基之單體，乙烯基吡咯啶酮、乙烯基吡啶、乙烯基咔唑等雜環系鹼性單體等。 Examples of the (meth)acrylate monomer contained in the main component of the acrylic copolymer (2-A1) include methyl (meth)acrylate, ethyl (meth)acrylate, (meth)acrylate Propyl acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, second-butyl (meth)acrylate, third-butyl (meth)acrylate , Amyl (meth)acrylate, Isopentyl (meth)acrylate, Neopentyl (meth)acrylate, Hexyl (meth)acrylate, Cyclohexyl (meth)acrylate, Heptyl (meth)acrylate ester, 2-ethylhexyl acrylate, n-octyl acrylate, isooctyl acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, tertiary butylcyclohexyl (meth)acrylate, Decyl (meth)acrylate, Isodecyl (meth)acrylate, Undecyl (meth)acrylate, Lauryl (meth)acrylate, Cetyl (meth)acrylate, (Meth)acrylate ) stearyl acrylate, isostearyl (meth)acrylate, behenyl (meth)acrylate, iso(meth)acrylate

Base ester, 2-phenoxyethyl (meth)acrylate, 3,5,5-trimethylcyclohexyl acrylate, p-cumylphenol EO modified (meth)acrylate, (meth) Dicyclopentyl acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, benzyl (meth)acrylate, and the like. Hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, glycerin (meth)acrylate etc. which have a hydrophilic group or an organic functional group etc. can also be used Hydroxyl-containing (meth)acrylate, or (meth)acrylic acid, 2-(meth)acryloxyethylhexahydrophthalic acid, 2-(meth)acryloxypropylhexahydro Phthalic acid, 2-(meth)acryloxyethylphthalic acid, 2-(meth)acryloxypropylphthalic acid, 2-(meth)acryloxyethylphthalic acid 2-(meth)acryloxypropylmaleic acid, 2-(meth)acryloxyethylsuccinic acid, 2-(meth)acryloxypropylmaleic acid, 2-(meth)acryloxypropylmaleic acid Carboxyl group-containing monomers such as propyl succinic acid, crotonic acid, fumaric acid, maleic acid, itaconic acid, monomethyl maleate, monomethyl itaconate, etc. Monomers containing acid anhydride groups such as diacid anhydride and itaconic anhydride, glycidyl (meth)acrylate, α-glycidyl ethacrylate, 3,4-epoxybutyl (meth)acrylate, etc. containing epoxy groups Monomers, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate and other amino-containing (meth)acrylate monomers, (meth)acrylamide, N-tert-butyl (meth)acrylamide, N-hydroxymethyl (meth)acrylamide, N-methoxymethyl (meth)acrylamide, N-butoxymethyl ( Meth)acrylamide, diacetoneacrylamide, maleimide, maleimide and other amido-containing monomers, vinylpyrrolidone, vinylpyridine, vinylcarbazole Heterocyclic basic monomers, etc.

In addition, styrene, tert-butylstyrene, α-methylstyrene, vinyltoluene, acrylonitrile, methacrylic acid copolymerizable with the above-mentioned acrylic monomer or methacrylic monomer can also be suitably used. Various vinyl monomers such as nitrile, vinyl acetate, vinyl propionate, alkyl vinyl ether, hydroxyalkyl vinyl ether, alkyl vinyl monomer, etc.

Moreover, it is preferable that the backbone component of an acryl-type copolymer (2-A1) contains a hydrophobic (meth)acrylate monomer and a hydrophilic (meth)acrylate monomer as a structural unit.

If the main component of the acrylic copolymer (2-A1) is composed of only hydrophobic monomers, it is confirmed that there is a tendency of wet heat whitening. Therefore, it is preferable to introduce a hydrophilic monomer into the main component to prevent wet heat whitening.

Specifically, as the main component of the above-mentioned acrylic copolymer (2-A1), a combination of a hydrophobic (meth)acrylate monomer, a hydrophilic (meth)acrylate monomer, and a macromonomer can be mentioned. A copolymer component formed by random copolymerization of polymerizable functional groups at the terminal.

基酯、(甲基)丙烯酸環己酯、(甲基)丙烯酸二環戊烯氧基乙酯、甲基丙烯酸甲酯。 Here, as the above-mentioned hydrophobic (meth)acrylate monomer, alkyl esters having no polar groups (among which, methyl acrylate is not included) are preferred, for example, n-butyl (meth)acrylate , Isobutyl (meth)acrylate, second butyl (meth)acrylate, third butyl (meth)acrylate, pentyl (meth)acrylate, isoamyl (meth)acrylate, (meth) ) Neopentyl acrylate, (meth)hexyl acrylate, (meth)cyclohexyl acrylate, (meth)heptyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, isooctyl acrylate, ( Nonyl methacrylate, isononyl (meth)acrylate, tert-butylcyclohexyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, (meth) Undecyl acrylate, lauryl (meth)acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, (meth)acrylic acid Behenyl Ester, (Meth) Acrylic Iso

base ester, cyclohexyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, methyl methacrylate.

Moreover, as a hydrophobic vinyl monomer, vinyl acetate, styrene, tert-butylstyrene, (alpha)-methylstyrene, vinyl toluene, an alkyl vinyl monomer, etc. are mentioned, for example.

As the above-mentioned hydrophilic (meth)acrylate monomer, methyl acrylate or an ester having a polar group is preferable, for example, methyl acrylate, (meth)acrylic acid, tetrahydrofurfuryl (meth)acrylate Or (meth)acrylate or (meth)acrylate containing hydroxyl groups such as hydroxyethyl (meth)acrylate, (meth)hydroxypropyl Acrylic acid, 2-(meth)acryloxyethyl hexahydrophthalate, 2-(meth)acryloxypropyl hexahydrophthalate, 2-(meth)acryloxy Ethylphthalate, 2-(meth)acryloxypropylphthalate, 2-(meth)acryloxyethylmaleic acid, 2-(meth)acrylyl oxygen propylmaleic acid, 2-(meth)acryloxyethylsuccinic acid, 2-(meth)acryloxypropylmaleic acid, crotonic acid, fumaric acid, cisuccinic acid Carboxyl-containing monomers such as butenedioic acid, itaconic acid, monomethyl maleate, and monomethyl itaconate, monomers containing acid anhydride groups such as maleic anhydride and itaconic anhydride, (form Base) glycidyl acrylate, α-glycidyl ethacrylate, 3,4-epoxybutyl (meth)acrylate and other monomers containing epoxy groups, methoxypolyethylene glycol (meth)acrylic acid Alkoxy polyalkylene glycol (meth)acrylate such as ester, N,N-dimethylacrylamide, hydroxyethylacrylamide, etc.

(branch components: macromonomer)

The acrylic copolymer (2-A1) preferably introduces a macromonomer as a branch component of the graft copolymer and contains repeating units derived from the macromonomer.

The so-called macromonomer system refers to a polymer monomer having a terminal polymerizable functional group and a high molecular weight skeleton component.

The glass transition temperature (Tg) of the macromonomer is preferably higher than the glass transition temperature of the copolymer components constituting the above-mentioned acrylic copolymer (2-A1).

Specifically, the glass transition temperature (Tg) of the macromonomer will affect the heating and melting temperature (melt temperature) of the adhesive composition (2-I), so the glass transition temperature (Tg) of the macromonomer is better 30° C. to 120° C., more preferably 40° C. or higher or 110° C. or lower, and more preferably 50° C. or higher or 100° C. or lower.

If it is such a glass transition temperature (Tg), by adjusting the molecular weight, it is possible to maintain excellent processability and storage stability, and it can be adjusted to heat-melt around 80°C.

The so-called glass transition temperature of the macromonomer refers to the glass transition temperature of the macromonomer itself, which can be measured by a differential scanning calorimeter (DSC). (Heating rate: 5°C/min, Tg is measured according to the inflection point of the baseline displacement)

In addition, in order to maintain the branched components close to each other at room temperature, as the adhesive composition undergoes physical cross-linking, and by heating to a moderate temperature, the above-mentioned physical cross-linking can be released to obtain fluidity It is also preferable to adjust the molecular weight or content of the macromonomer.

From this point of view, the macromonomer is preferably contained in the acrylic copolymer (2-A1) at a ratio of 5% by mass to 30% by mass, more preferably at least 6% by mass and at most 25% by mass, wherein More preferably, it is 8 mass % or more or 20 mass % or less.

Also, the number average molecular weight of the macromonomer is preferably 500 or more and less than 8000, more preferably 800 or more and less than 7500, and still more preferably 1000 or more and less than 7000.

As the macromonomer, a general manufacturer (for example, a macromonomer manufactured by Toagosei Co., Ltd., etc.) can be used appropriately.

The high molecular weight skeleton component of the macromonomer preferably comprises an acrylic polymer or a vinyl polymer.

基酯、(甲基)丙烯酸2-苯氧基乙酯、丙烯酸3,5,5-三甲基環己酯、對異丙苯基苯酚EO改性(甲基)丙烯酸酯、(甲基)丙烯酸二環戊酯、(甲基)丙烯酸二環戊烯酯、(甲基)丙烯 酸二環戊烯氧基乙酯、(甲基)丙烯酸苄酯、(甲基)丙烯酸羥基烷基酯、(甲基)丙烯酸、(甲基)丙烯酸縮水甘油酯、(甲基)丙烯醯胺、N,N-二甲基(甲基)丙烯醯胺、(甲基)丙烯腈、(甲基)丙烯酸烷氧基烷基酯、烷氧基聚伸烷基二醇(甲基)丙烯酸酯等(甲基)丙烯酸酯單體或苯乙烯、第三丁基苯乙烯、α-甲基苯乙烯、乙烯基甲苯、烷基乙烯基單體、乙酸乙烯酯、烷基乙烯基醚、羥基烷基乙烯基醚等各種乙烯基單體等，該等可單獨使用或組合兩種以上使用。 Examples of the high-molecular-weight skeleton component of the macromonomer include: methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, (meth)acrylate base) n-butyl acrylate, isobutyl (meth)acrylate, second butyl (meth)acrylate, third butyl (meth)acrylate, amyl (meth)acrylate, isobutyl (meth)acrylate Pentyl, neopentyl (meth)acrylate, hexyl (meth)acrylate, cyclohexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, Isooctyl acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, tert-butylcyclohexyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate ester, undecyl (meth)acrylate, lauryl (meth)acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate , Behenyl (meth)acrylate, Iso(meth)acrylate

Base ester, 2-phenoxyethyl (meth)acrylate, 3,5,5-trimethylcyclohexyl acrylate, p-cumylphenol EO modified (meth)acrylate, (meth) Dicyclopentyl acrylate, Dicyclopentenyl (meth)acrylate, Dicyclopentenyloxyethyl (meth)acrylate, Benzyl (meth)acrylate, Hydroxyalkyl (meth)acrylate, ( Meth)acrylic acid, glycidyl (meth)acrylate, (meth)acrylamide, N,N-dimethyl(meth)acrylamide, (meth)acrylonitrile, (meth)acrylamide (meth)acrylate monomers such as oxyalkyl esters, alkoxy polyalkylene glycol (meth)acrylates, or styrene, tert-butylstyrene, α-methylstyrene, vinyl Various vinyl monomers such as toluene, alkyl vinyl monomers, vinyl acetate, alkyl vinyl ethers, and hydroxyalkyl vinyl ethers can be used alone or in combination of two or more.

As a terminal polymerizable functional group of the said macromonomer, a methacryl group, an acryl group, a vinyl group etc. are mentioned, for example.

(Crosslinking agent (2-B1))

As the cross-linking agent (2-B1), for example, one having two or more cross-linking groups such as epoxy groups or isocyanate groups, oxetanyl groups, silanol groups, and (meth)acryl groups can be appropriately selected. crosslinking agent. Among them, in terms of reactivity or the strength of the obtained hardened product, polyamides having 2 or more (meth)acryl groups are preferred, and polyamides having 3 or more (meth)acryl groups are more preferred. Functional (meth)acrylates or (meth)acrylates with epoxy groups, isocyanate groups, and silanol groups.

After laminating and integrating the components of the image display device, the cross-linking agent (2-B1) is cross-linked in the adhesive material, so that the sheet loses its heat-meltability and is replaced by one that exhibits higher performance in high-temperature environments. Cohesion, to obtain excellent reliability against foaming.

Examples of such (meth)acrylates include 1,4-butanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, glycerin di(meth)acrylate, Glycerin glycidyl ether di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, tricyclodecane dimethanol di( Meth)acrylate, bisphenol A polyethoxy di(meth)acrylate, bisphenol A polyalkoxy di(meth)acrylate, bisphenol F polyalkoxy di(meth)acrylate Acrylic acid ester, polyalkylene glycol di(meth)acrylate, trimethylolpropane trioxyethyl(meth)acrylate, ε-caprolactone modified tris(2-hydroxyethyl) Isocyanurate tri(meth)acrylate, Pentaerythritol tri(meth)acrylate, Propoxylated pentaerythritol tri(meth)acrylate, Ethoxylated pentaerythritol tri(meth)acrylate, Pentaerythritol tetra(meth)acrylate Acrylates, propoxylated pentaerythritol tetra(meth)acrylate, ethoxylated pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, polyethylene glycol di(meth)acrylate, tri(propylene Acyloxyethyl) isocyanurate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate, tripentaerythritol hexa(meth)acrylate , tripentaerythritol penta(meth)acrylate, hydroxypivalate neopentyl glycol di(meth)acrylate, ε-caprolactone adduct of hydroxypivalate neopentyl glycol two (methyl ) acrylate, trimethylolpropane tri(meth)acrylate, alkoxylated trimethylolpropane tri(meth)acrylate, bis(trimethylolpropane)tetra(meth)acrylate, etc. Type polyfunctional monomers, in addition: polyester (meth)acrylate, epoxy (meth)acrylate, (meth)acrylate urethane, polyether (meth)acrylate, etc. Polyfunctional acrylate oligomers or isocyanate (meth)acrylate, 1,1-(bis(meth)acryloxymethyl)ethyl isocyanate, 2-(2-(meth)acryloxy (ethyloxy) ethyl isocyanate, (meth) glycidyl acrylate, (meth) hydroxyethyl acrylate glycidyl ether, (meth) hydroxypropyl acrylate glycidyl ether, (meth) hydroxybutyl acrylate Ester glycidyl ether etc.

Among those listed above, polyfunctional monomers or oligomers containing polar functional groups such as hydroxyl groups are preferred from the viewpoint of improving the adhesion to the adherend or the effect of suppressing wet heat whitening.

Among them, it is preferable to use a polyfunctional (meth)acrylate having a hydroxyl group or a carboxyl group.

Therefore, from the viewpoint of preventing wet heat whitening, as the above-mentioned acrylic copolymer (2-A1), that is, the main component of the graft copolymer, it is preferable to contain a hydrophobic acrylate monomer and an As the aqueous acrylate monomer, and furthermore, as the crosslinking agent (2-B), it is preferable to use a polyfunctional (meth)acrylate having a hydroxyl group.

The content of the crosslinking agent (2-B1) is not particularly limited. As a standard, it is preferably 0.5 to 20 parts by mass with respect to 100 parts by mass of the acrylic copolymer (2-A1), more preferably at least 1 part by mass and at most 15 parts by mass, and even more preferably at least 2 parts by mass Or a ratio of 10 parts by mass or less.

By containing the crosslinking agent (2-B1) within the above range, the shape stability of the adhesive sheet 2 in the uncrosslinked state and the foaming resistance reliability of the crosslinked adhesive can be simultaneously realized. Among them, in terms of balance with other elements, it may also exceed this range.

(Photopolymerization Initiator (2-C1))

The photopolymerization initiator (2-C1) functions as a reaction initiation aid for the crosslinking reaction of the above-mentioned crosslinking agent (2-B1).

As the photopolymerization initiator, conventionally known ones can be appropriately used. Among them, a photopolymerization initiator responsive to ultraviolet rays having a wavelength of 380 nm or less is preferable from the viewpoint of easy control of the crosslinking reaction.

On the other hand, a photopolymerization initiator that responds to light with a wavelength longer than 380 nm is preferable in that the induced light easily reaches the deep portion of the adhesive sheet 2 .

Photopolymerization initiators are roughly divided into two categories according to the mechanism of free radical generation, roughly divided into: cleavage-type photopolymerization initiators that can break and decompose the single bond of the photopolymerization initiator itself to generate free radicals, and The photoexcited initiator and the hydrogen donor and donor in the system form an excited complex, which can transfer the hydrogen of the hydrogen donor and donor to the hydrogen abstraction type photopolymerization initiator.

As the cleavage-type photopolymerization initiator among these, it decomposes into other compounds when free radicals are generated by light irradiation, and loses its function as a reaction initiator once it is excited. Therefore, it is preferable because it does not remain as an active material in the adhesive material after the crosslinking reaction is completed, and there is no possibility of causing unexpected photodegradation to the adhesive material.

On the other hand, when a hydrogen abstraction photopolymerization initiator is irradiated with active energy rays such as ultraviolet rays to generate a free radical reaction, no decomposition product such as a cracking photopolymerization initiator is generated, so it is difficult to become Volatile components can reduce the damage to the adherend and are more useful in this respect.

啉基苯基)丁烷-1-酮、2-甲基-1-[4-(甲硫基)苯基]-2-

啉基丙烷-1-酮、2-(二甲胺基)-2-[(4-甲基苯基)甲基]-1-[4-(4-

啉基)苯基]-1-丁酮、雙(2,4,6-三甲基苯甲醯基)-苯基氧化膦、2,4,6-三甲基苯甲醯基二苯基氧化膦或該等之衍生物等。 Examples of the cleavage-type photoinitiator include: 2,2-dimethoxy-1,2-diphenylethan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2 -Methyl-1-phenyl-propan-1-one, 1-(4-(2-hydroxyethoxy)phenyl)-2-hydroxy-2-methyl-1-propan-1-one, 2 -Hydroxy-1-[4-{4-(2-hydroxy-2-methyl-propionyl)benzyl}phenyl]-2-methyl-propan-1-one, oligo(2-hydroxy- 2-methyl-1-(4-(1-methylvinyl)phenyl)acetone), methyl phenylglyoxylate, 2-benzyl-2-dimethylamino-1-(4-

Linylphenyl) butane-1-one, 2-methyl-1-[4-(methylthio)phenyl]-2-

Linyl propan-1-one, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-

Phenyl)phenyl]-1-butanone, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenyl Phosphine oxide or their derivatives, etc.

、2-氯-9-氧硫

、3-甲基-9-氧硫

、2,4-二甲基-9-氧硫

、2-甲基蒽醌、2-乙基蒽醌、2-第三丁基蒽醌、2-胺基蒽醌或其衍生物等。 Examples of the hydrogen abstraction type photoinitiator include: benzophenone, 4-methyl-benzophenone, 2,4,6-trimethylbenzophenone, 4-phenylbenzophenone Ketone, 3,3'-dimethyl-4-methoxybenzophenone, 4-(meth)acryloxybenzophenone, methyl 2-benzoylbenzoate, benzoyl Methyl methanoate, bis(2-phenyl-2-glyoxylate)oxybisethylene, 4-(1,3-acryloyl-1,4,7,10,13-pentaoxotridecane base) benzophenone, 9-oxosulfur

, 2-Chloro-9-oxosulfur

, 3-methyl-9-oxosulfur

, 2,4-Dimethyl-9-oxosulfur

, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-aminoanthraquinone or its derivatives, etc.

However, it is not limited to what was listed above as a photoinitiator. Any of the cleavage type photopolymerization initiators and hydrogen abstraction type photopolymerization initiators listed above may be used, or two or more of them may be used in combination.

The content of the photopolymerization initiator (2-C1) is not particularly limited. As a standard, it is preferably 0.1 to 10 parts by mass relative to 100 parts by mass of the acrylic copolymer (2-A1), more preferably at least 0.5 parts by mass or less than 5 parts by mass, and even more preferably 1 part by mass More than or equal to 3 parts by mass or less.

Moderate reaction sensitivity to active energy rays can be obtained by making content of a photoinitiator (2-C1) into the said range.

(other ingredients)

The adhesive composition (2-I) may contain, as components other than the above, known components formulated in ordinary adhesive compositions. For example, if necessary, various types such as adhesion-imparting resins, antioxidants, photostabilizers, metal deactivators, anti-aging agents, moisture absorbers, polymerization inhibitors, ultraviolet absorbers, rust inhibitors, silane coupling agents, and inorganic particles can be appropriately contained. additive.

Moreover, a reaction catalyst (tertiary amine type compound, quaternary ammonium type compound, tin laurate compound, etc.) may be contained suitably as needed.

<Adhesive composition (2-II)>

Examples of the adhesive composition (2-II) include monomers having a glass transition temperature (Tg) of less than 0°C and monomers having a glass transition temperature (Tg) of 0°C to less than 80°C. b and monomer c with a glass transition temperature (Tg) above 80°C are copolymerized at a molar ratio of a:b:c=10~40:90~35:0~25 and the weight average molecular weight is 50000~ 400000 (meth)acrylic copolymer (2-A2) of (meth)acrylate copolymer or vinyl copolymer; crosslinking agent (2-B2) and photopolymerization initiator (2-C2) resin composition.

In addition, the number average molecular weight and weight average molecular weight are conversion values using polystyrene as a standard substance using gel permeation chromatography (GPC).

((meth)acrylic copolymer (2-A2))

The (meth)acrylic copolymer (2-A2) as the base polymer is preferably a (meth)acrylate copolymer or vinyl copolymer.

From the point of view of achieving both shape retention and heat-fusibility at room temperature, the weight-average molecular weight of the above-mentioned (meth)acrylate copolymer or vinyl copolymer is preferably 50,000 to 400,000, more preferably 60,000 It is more than or equal to 350,000, and more preferably more than or equal to 70,000 or less than 300,000.

For acrylate copolymers, the glass transition temperature (Tg) or properties such as molecular weight.

In this case, as an acrylic monomer which comprises an acrylate copolymer, 2-ethylhexyl acrylate, n-octyl acrylate, isooctyl acrylate, n-butyl acrylate, ethyl acrylate, etc. are mentioned as a main raw material, for example.

In addition to these, a (meth)acrylic monomer having various functional groups may be copolymerized with the above-mentioned acrylic monomer for the purpose of imparting cohesive force, imparting polarity, or the like.

Examples of the (meth)acrylic monomer having a functional group include methyl methacrylate, methyl acrylate, hydroxyethyl acrylate, acrylic acid, glycidyl acrylate, N-substituted acrylamide, acrylonitrile, Methacrylonitrile, fluorine-containing alkyl acrylate, acrylate containing organosilyloxyl group, etc.

On the other hand, examples of vinyl copolymers include various vinyl copolymers such as vinyl acetate, alkyl vinyl ether, and hydroxyalkyl vinyl ether, which can be copolymerized with the above-mentioned acrylic monomer or methacrylic monomer. Monomers are also suitable for polymerization of vinyl copolymers.

As the (meth)acrylic copolymer (2-A2) of this adhesive sheet 2, it is preferable that the monomer a whose glass transition temperature (Tg) is less than 0°C and the glass transition temperature (Tg) be 0°C or higher and below 80°C Monomer b and monomer c with a glass transition temperature (Tg) above 80°C are copolymerized at a molar ratio of a:b:c=10~40:90~35:0~25 (methyl) Acrylate copolymer or vinyl copolymer.

In this case, each glass transition temperature (Tg) of the monomers a, b, and c is the respective glass transition temperature (Tg) when the monomer is produced into a polymer (homopolymerization).

The above-mentioned monomer a is preferably, for example, a (meth)acrylate monomer having an alkyl structure having a side chain having 4 or more carbon atoms.

In this case, the side chain having 4 or more carbon atoms may include a straight chain or a branched carbon chain.

More specifically, the above-mentioned monomer a is preferably a (meth)acrylate monomer having a straight-chain alkyl structure with 4 to 10 carbons or a (meth)acrylate monomer having a branched alkyl structure with 6 to 18 carbons. ) acrylate monomer.

Here, examples of the "(meth)acrylate monomer having a linear alkyl structure having 4 to 10 carbon atoms" include n-butyl acrylate, n-hexyl acrylate, n-octyl acrylate, n-nonyl acrylate, N-decyl acrylate, etc.

On the other hand, examples of "(meth)acrylate monomers having a branched chain alkyl structure having 6 to 18 carbon atoms" include 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, 2-methylhexyl acrylate, isooctyl acrylate, isononyl acrylate, isodecyl acrylate, isodecyl methacrylate, and the like.

The above-mentioned monomer b is preferably a (meth)acrylate monomer with 4 or less carbon atoms, a (meth)acrylate monomer with a ring skeleton in the side chain, a vinyl monomer with 4 or less carbon atoms, or a vinyl monomer with a side chain with Vinyl monomer with ring skeleton.

Among them, the above-mentioned monomer b is particularly preferably a vinyl monomer having 4 or less carbon atoms in the side chain.

Here, examples of the "(meth)acrylate monomer having 4 or less carbon atoms" include methyl acrylate, ethyl methacrylate, n-propyl acrylate, n-propyl methacrylate, isopropyl acrylate, Isopropyl methacrylate, n-butyl methacrylate, tert-butyl acrylate, isobutyl acrylate, isobutyl methacrylate, etc.

基酯、丙烯酸環己酯、甲基丙烯酸環己酯、1,4-環己烷二甲醇單丙烯酸酯、甲基丙烯酸四氫糠酯、丙烯酸苄酯、甲基丙烯酸苄酯、丙烯酸苯氧基乙酯、甲基丙烯酸苯氧基乙酯、丙烯酸2-羥基-3-苯氧基丙酯、3,3,5-三甲基環己醇丙烯酸酯、環狀三羥甲基丙烷甲縮醛丙烯酸酯、4-乙氧化異丙苯基苯酚丙烯酸酯、丙烯酸二環戊烯氧基乙酯、甲基丙烯酸二環戊烯氧基乙酯、丙烯酸二環戊烯酯等。 Examples of the "(meth)acrylate monomer having a cyclic skeleton in the side chain" include:

methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, 1,4-cyclohexanedimethanol monoacrylate, tetrahydrofurfuryl methacrylate, benzyl acrylate, benzyl methacrylate, phenoxy acrylate Ethyl ester, phenoxyethyl methacrylate, 2-hydroxy-3-phenoxypropyl acrylate, 3,3,5-trimethylcyclohexanol acrylate, cyclic trimethylolpropane formal Acrylates, 4-ethoxylated cumylphenol acrylate, dicyclopentenyloxyethyl acrylate, dicyclopentenyloxyethyl methacrylate, dicyclopentenyl acrylate, and the like.

Examples of "vinyl monomers having 4 or less carbon atoms" include: vinyl acetate, vinyl propionate, vinyl butyrate, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, vinyl ether etc.

基乙烯醚、降

烯基乙烯醚等。其中，尤佳為側鏈之碳數為4以下之乙烯基單體或側鏈之碳數為4以下之丙烯酸酯單體。 Examples of the "vinyl monomer having a cyclic skeleton in the side chain" include styrene, cyclohexyl vinyl ether, nor

Vinyl ether, nor

Alkenyl vinyl ether, etc. Among them, a vinyl monomer having 4 or less carbon atoms in the side chain or an acrylate monomer having 4 or less carbon atoms in the side chain is particularly preferable.

The above-mentioned monomer c is preferably a (meth)acrylate monomer having one or less carbon atoms in the side chain or a (meth)acrylate monomer having a ring skeleton in the side chain.

Here, examples of the "(meth)acrylate monomer having one or less carbon atoms in the side chain" include methyl methacrylate, acrylic acid, methacrylic acid, and the like.

基酯、甲基丙烯酸3,3,5-三甲基環己酯、丙烯酸二環戊酯、甲基 丙烯酸二環戊酯、甲基丙烯酸二環戊烯酯等。 Examples of the "(meth)acrylate monomer having a cyclic skeleton in the side chain" include:

Base ester, 3,3,5-trimethylcyclohexyl methacrylate, dicyclopentyl acrylate, dicyclopentanyl methacrylate, dicyclopentenyl methacrylate, etc.

If the (meth)acrylic copolymer (2-A2) contains monomer a, monomer b and monomer c at a molar ratio of a:b:c=10~40:90~35:0~25 The polymerized (meth)acrylate copolymer or ethylene-based copolymer can adjust the peak of Tanδ to 0~20°C, and can maintain the shape of a sheet in the normal state, that is, at room temperature. Also, it has the property of sticking to the adherend with light force for a short time (called "adhesive"). In addition, when heated to a heat-melting temperature, it exhibits fluidity and can be filled to every corner following the step of the bonding surface.

Therefore, from this point of view, the difference between monomer a, monomer b, and monomer c in the (meth)acrylate copolymer or vinyl copolymer constituting the (meth)acrylic copolymer (2-A2) The molar ratio is preferably a:b:c=10~40:90~35:0~25, more preferably 13~40:87~35:0~23, and more preferably 15~40:85 ~38:2~20.

Also, from the same viewpoint as above, monomer a, monomer b, and monomer in the (meth)acrylate copolymer or vinyl copolymer constituting the (meth)acrylic copolymer (2-A2) The molar ratio of body c is preferably b>a>c.

(Crosslinking agent (2-B2))

By crosslinking the crosslinking agent (2-B2) in the adhesive sheet 2, the adhesive sheet 2 exhibits high cohesive force under high temperature environment, and can obtain excellent reliability against foaming.

As such a crosslinking agent (2-B2), for example, one having two or more epoxy groups or isocyanate groups, oxetanyl groups, silanol groups, (meth)acryl groups and other crosslinking properties can be selected appropriately. base crosslinking agent. Among them, in terms of reactivity or the strength of the obtained hardened product, polyamides having 2 or more (meth)acryl groups are preferred, and polyamides having 3 or more (meth)acryl groups are more preferred. Functional (meth)acrylates or (meth)acrylates with epoxy groups, isocyanate groups, and silanol groups.

Examples of such (meth)acrylates include 1,4-butanediol di(meth)acrylate, glycerin di(meth)acrylate, 1,6-hexanediol di(methyl) Acrylates, 1,9-nonanediol di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, bisphenol A polyethoxy di(meth)acrylate, bisphenol A Polypropoxy di(meth)acrylate, bisphenol F polyethoxy di(meth)acrylate, ethylene glycol di(meth)acrylate, trimethylolpropane trioxyethyl(methyl) ) acrylate, ε-caprolactone modified tris(2-hydroxyethyl)isocyanurate tri(meth)acrylate, pentaerythritol tri(meth)acrylate, propoxylated pentaerythritol tri(meth)acrylate ester, ethoxylated pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, propoxylated pentaerythritol tetra(meth)acrylate, ethoxylated pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate ) acrylate, polyethylene glycol di(meth)acrylate, tris(acryloxyethyl)isocyanurate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, Dipentaerythritol penta(meth)acrylate, tripentaerythritol hexa(meth)acrylate, tripentaerythritol penta(meth)acrylate, hydroxypivalic acid neopentyl glycol di(meth)acrylate, hydroxypivalic acid Di(meth)acrylate of ε-caprolactone adduct of neopentyl glycol ester, trimethylolpropane tri(meth)acrylate, trimethylolpropane polyethoxytri(meth)acrylate Acrylate, bis(trimethylolpropane)tetra(meth)acrylate and other ultraviolet curable polyfunctional monomers, and also polyester (meth)acrylate, epoxy (meth)acrylate , (meth)acrylate urethane, polyether (meth)acrylate and other polyfunctional acrylate oligomers or isocyanate (meth)acrylate, 1,1-(bis(meth)acryl Oxymethyl)ethylisocyanate, 2-(2-(meth)acryloxyethyloxy)ethylisocyanate, glycidyl (meth)acrylate, glycidyl (meth)hydroxyethylacrylate Ether, hydroxypropyl (meth)acrylate glycidyl ether, hydroxybutyl (meth)acrylate glycidyl ether, etc.

Among the above listed, it is to improve the adhesion or heat resistance to the adherend, and to improve the heat and humidity whitening. From the viewpoint of the inhibitory effect, polyfunctional monomers or oligomers containing polar functional groups are preferred. Among them, it is preferable to use a polyfunctional (meth)acrylate having an isocyanuric acid ring skeleton.

The content of the crosslinking agent (2-B2) is not particularly limited. As a standard, it is preferably 0.5 to 20 parts by mass relative to 100 parts by mass of the (meth)acrylic copolymer (2-A2), more preferably at least 1 part by mass and at most 15 parts by mass, and even more preferably 0.5 to 20 parts by mass The ratio of 2 mass parts or more or 10 mass parts or less.

By containing the crosslinking agent (2-B2) within the above range, the shape stability of the adhesive sheet 2 in the uncrosslinked state and the foaming resistance reliability of the crosslinked adhesive can be simultaneously realized. Among them, in terms of balance with other elements, it may also exceed this range.

(Photopolymerization Initiator (2-C2))

The photopolymerization initiator (2-C2) functions as a reaction initiation aid for the crosslinking reaction of the above-mentioned crosslinking agent (2-B2), and the above-mentioned photopolymerization initiator (2-C1) can be used appropriately recorded.

The content of the photopolymerization initiator (2-C2) is not particularly limited. As a standard, it is preferably 0.1 to 10 parts by mass relative to 100 parts by mass of the (meth)acrylic copolymer (2-A2), more preferably not less than 0.5 parts by mass and not more than 5 parts by mass, and even more preferably It is contained in the ratio of 1 mass part or more or 3 mass parts or less.

Moderate reaction sensitivity to active energy rays can be obtained by making content of a photoinitiator (2-C2) into the said range.

(other ingredients)

The adhesive composition (2-II) may contain, as components other than the above, known components formulated in ordinary adhesive compositions. For example, if necessary, various types such as adhesion-imparting resins, antioxidants, photostabilizers, metal deactivators, anti-aging agents, moisture absorbers, polymerization inhibitors, ultraviolet absorbers, rust inhibitors, silane coupling agents, and inorganic particles can be appropriately contained. additive.

Moreover, a reaction catalyst (tertiary amine type compound, quaternary ammonium type compound, tin laurate compound, etc.) may be contained suitably as needed.

<Manufacturing method of adhesive sheet X>

The method for producing the adhesive sheet X includes: a solution coating method in which the adhesive composition (2-I) and (2-II) prepared by a known method are dissolved in a solvent and applied; or the adhesive composition The hot-melt coating method in which the agent composition is heated, melted and coated, etc. Among these, it will not specifically limit as long as the objective adhesive sheet can be obtained, It can manufacture by a well-known method.

Furthermore, in the above-mentioned adhesive compositions (2-I) and (2-II), when forming a thin film with a thickness of 50 μm or less, it is preferable to use a solution coating method in terms of the ease of thickness control. On the other hand, when forming an adhesive sheet with a thickness of 50 μm or more, it is preferable to use a hot-melt coating method in terms of environmental pollution and ease of forming a thick film.

<Laminated structure>

The adhesive sheet 2 may be a sheet comprising a single layer, or a multi-layer sheet formed by laminating two or more layers.

When this adhesive sheet 2 is made into a multi-layered transparent double-sided adhesive, as a laminated structure, specifically, there may be mentioned: 2 laminated with this adhesive composition 2 and another adhesive resin composition. 2-layer structure, or 2 types of 3-layer structure in which this adhesive composition 2 is placed on the front and back via an intermediate resin layer, or this adhesive composition 2, intermediate resin composition, and other adhesive resin combinations are laminated sequentially There are three kinds of three-layer structures made of things. Among them, it is preferable that the outermost layer is formed from the present adhesive composition 2, such as the above-mentioned adhesive composition (2-I) (2-II).

In addition, the present adhesive composition 2 and other adhesive resin compositions may be molded in a sheet form on separate release films or image display device components, and both adhesive surfaces may be laminated to obtain the present adhesive sheet 2. In addition, the present adhesive composition 2, the intermediate resin composition and the adhesive tree can also be used in sequence. The resin composition is co-extruded to obtain the adhesive sheet 2 of two types and three layers. In addition, the adhesive composition 2 or other adhesive resin compositions can be laminated on the front and back of the middle resin layer to obtain the adhesive sheet. Material 2.

Also, for example, it may be a substrate-attached adhesive sheet having an adhesive layer formed from the present adhesive composition 2 (referred to as "this adhesive layer 2") on the substrate, or may be a substrate-free sheet without a substrate. Adhesive sheet. Furthermore, it may be a double-sided adhesive sheet having the above-mentioned present adhesive layer 2 on both upper and lower sides, or a single-sided adhesive sheet having the above-mentioned present adhesive layer 2 only on one side of the upper and lower sides.

<thickness>

As the thickness of the adhesive sheet 2, the thickness of the maximum thickness portion is preferably 250 μm or less from the viewpoint of not hindering the thinning of the image display device. In other words, the adhesive sheet 2 can be a sheet with a uniform thickness, or a non-uniform sheet with parts of different thicknesses. In the case of a sheet with non-uniform thickness, the thickness of the thickest part is preferably 250 μm or less .

Also, the thickness of the maximum thickness portion is preferably at least 5 μm, more preferably at least 10 μm, and still more preferably at least 15 μm, from the viewpoint of not hindering the adhesion with the adherend or shock absorption.

<purpose>

This adhesive sheet 2 can be used in its original form, and can also be used as follows. However, the utilization method of the adhesive sheet 2 is not limited.

(adhesive sheet laminate 2)

This adhesive sheet 2 can be provided as the adhesive sheet laminated body 2 provided with the structure which consists of one side of this adhesive sheet 2, or a double-layer release film, for example.

At this time, the adhesive sheet 2 can be, for example, as shown in Fig. 1 or Fig. 2, with the above-mentioned soft part and hard part in the sheet surface, and also can be as shown in Fig. 3 (A) (B). show, in the adhesive sheet to The end face on one side has the form of the above-mentioned hard part. In this case, the entire surface of the end surface may be the hard portion, or a part of the end surface may be the hard portion. In addition, hard parts may be provided on the end surface and inside the surface.

As shown in Fig. 4 (A) (B), the end face of the adhesive sheet 2 is in the form of a hard part, for example, even in severe environments such as high temperature and high humidity, the exposed end face can not be exposed. Sticky, so it can be stored better.

(Laminate 2 for constituting the image display device)

In the case where the present adhesive sheet 2 has the aforementioned soft portion and the aforementioned hard portion on the surface of the sheet, for example, it can be produced and provided with a space between two image display device constituent members interposed therebetween. The laminated body for constituting an image display device (hereinafter referred to as "the laminated body 2 for constituting an image display device") having the above-mentioned configuration.

The laminate 2 for constituting an image display device can be produced, for example, by laminating a constituent member for an image display device having an opaque portion and a light-transmitting portion on the bonding surface through the above-mentioned adhesive sheet X and other image display components. The device component irradiates the above-mentioned adhesive sheet X with light through the former image display device component, and partially photocures the adhesive sheet.

As an example of the laminate 2 for constituting the image display device, in addition to the laminate including the protective panel/this adhesive sheet 2/polarizing film, for example: image display panel/this adhesive sheet 2/touch Control panel, image display panel/this adhesive sheet 2/protective panel, image display panel/this adhesive sheet 2/touch panel/this adhesive sheet 2/protective panel, polarizing film/this adhesive sheet 2/ Configuration example of touch panel, polarizing film/this adhesive sheet 2/touch panel/this adhesive sheet 2/protection panel.

The protection panel and the image display panel may also be those in which a touch panel sensor is incorporated in the protection panel or the image display panel itself.

(this image display device 2)

An image display device (hereinafter referred to as "this image display device 2") can also be configured using the adhesive sheet 2 or the above-mentioned image display device constituting laminate.

That is, the image display device 2 is provided with at least two face-to-face constituent members for an image display device, and at least one of the constituent members for an image display device has an opaque portion and a light-transmitting portion on the bonding surface. A device, the image display device may be configured as an image display device having the following characteristics: it is an image display device having a structure in which an adhesive sheet is filled between the above-mentioned two constituent members for an image display device, The gel fraction of the above-mentioned adhesive sheet in contact with the above-mentioned light-transmitting portion is 40% or more, and the gel fraction of the position in contact with the above-mentioned opaque portion is less than 1%.

In the above-mentioned laminated body 2 for constituting the image display device and the image display device 2, the bonded surface has a portion that does not transmit light of a wavelength required for light hardening such as the printed portion around the screen (referred to in the present invention as A component member for an image display device that is the “opaque portion”) and a portion through which light of a wavelength required for photocuring (referred to as a “transmittance portion” in the present invention) is bonded to other component members for an image display device. When appropriate, make the gel fraction of the position in contact with the above-mentioned opaque part less than 1%, and the gel fraction of the position in contact with the above-mentioned light-transmitting part is more than 40%, so as to alleviate the problem caused by the opacity. The stress borne by the light part can reduce the strain generated by the part, and it can also have a higher cohesive force so that the adherends can be firmly bonded to each other.

Furthermore, the gel fraction at the position in contact with the opaque portion is preferably less than 1%, more preferably less than 0.8%.

On the other hand, the gel fraction at the position in contact with the light-transmitting portion is more preferably 40% or more, and more preferably 45% or more.

An example of a preferable manufacturing method of the image display device 2 will be described.

First, the above-mentioned adhesive sheet X is heated to be thermally fused, and the constituent member for image display device 1 and the constituent member for image display device 3 having the printed portion (1) are laminated through the above-mentioned adhesive sheet X. At this stage, since the adhesive sheet X is moderately soft, it can fully follow a step difference, maintaining storage stability.

Then, light such as ultraviolet rays is irradiated from the outside of the constituent member 1 for an image display device. Thus, because the printing part (1) shields the light, the light cannot reach the part that is in contact with the printing part (1), or the light that reaches is significantly restricted. The contact part of the optical part (3) can undergo a crosslinking reaction and be photohardened, which can achieve excellent peeling resistance and foaming resistance.

As the constituent members for the above two image display devices, for example, computer, mobile terminal (PDA), game machine, television (TV), car navigation, touch panel, tablet and other LCD, PDP or EL etc. Components of display devices. More specifically, for example, any one of the group consisting of a touch panel, an image display panel, a surface protection panel, and a polarizing film, or a laminate including a combination of two or more thereof can be used.

(adhesive sheet reel)

As shown in FIG. 5, the adhesive sheet 2 can be rolled into a roll shape. For example, the adhesive sheet X may be rolled into a roll, and only the end surface thereof may be irradiated with light to make it photocured, or the original adhesive sheet 2 , which is light-cured only on the end surface, may be rolled into a roll. In any case, if the end surface of the adhesive sheet rolled into a roll form is a light-hardened portion, the exposed roll end surface will not be sticky even in severe environments such as high temperature and high humidity, so it can be compared Keep well.

<This adhesive sheet 3>

Another example of the embodiment of the present invention is a double-sided adhesive sheet (hereinafter referred to as "this adhesive sheet 3") characterized in that it contains 100 parts by mass of (meth)acrylic copolymer (3-A) , an adhesive resin composition comprising 0.5 to 20 parts by mass of a crosslinking agent (3-B) and 0.1 to 5 parts by mass of a photopolymerization initiator (3-C) (hereinafter referred to as "this adhesive resin composition 3") ), and regarding the tensile modulus, the ratio ( _{X 1 /} X ₂ ) of the tensile modulus (X 1 ) before photocrosslinking to the tensile modulus (X ₂ ) after photocrosslinking becomes 3 or more.

In the field of image display devices centered on mobile phones and mobile terminals, in addition to thinning and high precision, the diversification of design is also progressing, and new issues have arisen along with it. For example, a frame-shaped black concealed portion is usually printed on the periphery of the surface protection panel. Therefore, an adhesive sheet for bonding components having such a printed portion is required to have printing level followability that can follow the printing level and fill to every corner. At this time, when there is no adhesiveness (stickiness) before photocrosslinking, the bonding operation is not easy,

Therefore, the present invention intends to provide a photocrosslinkable adhesive sheet, which has adhesiveness even before photocrosslinking. After bonding, the adhesive sheet 3 with sufficient hardness can be obtained.

This adhesive sheet 3 has the characteristic that the difference in tensile elastic modulus (X ₁ ) before and after photo-crosslinking is significantly large, and it has adhesiveness even before photo-crosslinking, and the adhesive material will not flow too much when laminating. The adhesive resin composition overflows or collapses, and then obtains sufficient hardness after photo-crosslinking.

<This adhesive resin composition 3>

This adhesive resin composition 3 is a resin composition containing a (meth)acrylic copolymer (3-A), a crosslinking agent (3-B), and a photopolymerization initiator (3-C) as described above.

<(Meth)acrylic copolymer (3-A)>

The (meth)acrylic copolymer (3-A) as the base polymer is preferably a graft copolymer (3-A1) having a macromonomer as a branch component.

Here, the so-called "base polymer" refers to the main component of this adhesive resin composition 3 of resin. The specific content of the base polymer is not specified, but as a standard, it is preferably at least 50% by mass of the resin contained in the present adhesive resin composition 3, more preferably at least 80% by mass, and even more preferably at least 90% by mass. Resin of mass % or more (including 100 mass %). Furthermore, when there are two or more base polymers, the total amount thereof is the above-mentioned content.

(main ingredient)

It is preferable that the backbone component of the said graft copolymer (3-A1) contains the copolymer component containing the repeating unit derived from (meth)acrylate.

The glass transition temperature of the copolymer constituting the main component of the graft copolymer (3-A1) is preferably -70 to 0°C.

In this case, the glass transition temperature of the copolymer component constituting the backbone component means the glass transition temperature of a polymer obtained by copolymerizing only the monomer components constituting the backbone component of the graft copolymer (3-A1). Specifically, it refers to the value calculated by Fox's calculation formula from the glass transition temperature and composition ratio of the polymer obtained from the homopolymer of the respective components of the copolymer.

In addition, the calculation formula of Fox means the calculated value obtained by the following formula, and can be obtained using the value described in the polymer handbook [Polymer Handbook, J. Brandrup, Interscience, 1989].

1/(273+Tg)=Σ(Wi/(273+Tgi))

[Where, Wi represents the weight fraction of monomer i, and Tgi represents the Tg (°C) of the homopolymer of monomer i]

The glass transition temperature of the copolymer component constituting the main component of the above-mentioned graft copolymer (3-A1) affects the flexibility of the present adhesive resin composition 3 at room temperature, or the present adhesive resin composition 3 affects the flexibility of the substrate. The wettability of the adhesive, that is, the adhesiveness affects, so in order to make the adhesive resin composition 3 obtain moderate adhesiveness (viscosity) at room temperature, the glass transition temperature is preferably -70°C~0 °C, more preferably above -65°C or below -5°C, especially preferably above -60°C or below - Below 10°C.

Among them, even if the glass transition temperature of the copolymer components is the same temperature, the viscoelasticity can be adjusted by adjusting the molecular weight. For example, by reducing the molecular weight of the copolymer component, it can be made more flexible.

Examples of the (meth)acrylate monomer contained in the main component of the graft copolymer (3-A1) include: 2-ethylhexyl acrylate, n-octyl acrylate, isooctyl acrylate, n-octyl acrylate Butyl ester, ethyl acrylate, methyl methacrylate, methyl acrylate, etc. Hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, acrylic acid, methacrylic acid, glycidyl acrylate, Acrylamide, N,N-dimethylacrylamide, acrylonitrile, methacrylonitrile, etc.

In addition, various vinyl monomers such as vinyl acetate, alkyl vinyl ether, and hydroxyalkyl vinyl ether, which are copolymerizable with the above-mentioned acrylic monomer or methacrylic monomer, can also be suitably used.

In addition, the main component of the graft copolymer (3-A1) preferably contains a hydrophobic (meth)acrylate monomer and a hydrophilic (meth)acrylate monomer as constituent units.

If the main component of the graft copolymer (3-A1) is composed of only hydrophobic monomers, it is confirmed that there is a tendency of wet heat whitening, so it is preferable to introduce a hydrophilic monomer into the main component to prevent wet heat whitening.

Specifically, as the main component of the above-mentioned graft copolymer (3-A1), a mixture of a hydrophobic (meth)acrylate monomer, a hydrophilic (meth)acrylate monomer, and a macromonomer can be mentioned. A copolymer component formed by random copolymerization of polymerizable functional groups at the terminal.

基酯、(甲基)丙烯酸環己酯、(甲基)丙烯酸二環戊烯氧基乙酯、甲基丙烯酸甲酯、乙酸乙烯酯等。 Here, as the above-mentioned hydrophobic (meth)acrylate monomer, alkyl esters having no polar groups (among which, methyl acrylate is not included) are preferred, for example, n-butyl (meth)acrylate , n-hexyl (meth)acrylate, n-octyl (meth)acrylate, n-nonyl (meth)acrylate, n-decyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, (meth)acrylate base) 2-methylhexyl acrylate, isooctyl (meth)acrylate, isononyl (meth)acrylate, isodecyl (meth)acrylate, ethyl (meth)acrylate, (meth)acrylic acid n-propyl, isopropyl (meth)acrylate, tertiary butyl (meth)acrylate, isobutyl (meth)acrylate, iso(meth)acrylate

base ester, cyclohexyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, methyl methacrylate, vinyl acetate, etc.

As the above-mentioned hydrophilic (meth)acrylate monomer, methyl acrylate or an ester having a polar group is preferable, for example, methyl acrylate, (meth)acrylic acid, tetrahydrofurfuryl (meth)acrylate , 2-(meth)hydroxyethyl acrylate, methoxy polyethylene glycol (meth)acrylate, 2-(meth)acryloxyethyl succinic acid, 2-(meth)acryloxy Ethyl phthalic acid, 2-(meth)acryloxypropyl hexahydrophthalic acid, N,N-dimethylacrylamide, hydroxyethylacrylamide, etc.

(branch components: macromonomer)

As the branch component of the graft copolymer (3-A1), it is preferable to introduce a macromonomer and contain repeating units derived from the macromonomer.

The so-called macromonomer system refers to a polymer monomer having a terminal polymerizable functional group and a high molecular weight skeleton component.

The glass transition temperature (Tg) of the macromonomer is preferably higher than the glass transition temperature of the copolymer components constituting the graft copolymer (3-A1).

Specifically, the glass transition temperature (Tg) of the macromonomer will affect the heating and melting temperature (melt temperature) of the adhesive resin composition 3, so the glass transition temperature (Tg) of the macromonomer is preferably 30°C ~120°C, more preferably above 40°C or below 110°C, more preferably above 50°C or below 100°C.

If it is such a glass transition temperature (Tg), by adjusting the molecular weight, it is possible to maintain excellent processability and storage stability, and it can be adjusted to heat-melt around 80°C.

The so-called glass transition temperature of the macromonomer refers to the glass transition temperature of the macromonomer itself, which can be measured by a differential scanning calorimeter (DSC). (Heating rate: 5°C/min, Tg is measured according to the inflection point of the baseline displacement)

In addition, in order to keep the branch components close to each other at room temperature, the adhesive resin composition 3 is in a state of physical crosslinking, and the above physical crosslinking can be released by heating to a moderate temperature. To obtain fluidity, it is also preferable to adjust the molecular weight or content of the macromonomer.

From this point of view, the macromonomer is preferably contained in the graft copolymer (3-A1) at a ratio of 5 mass % to 30 mass %, more preferably 6 mass % or more or 25 mass % or less, wherein More preferably, it is 8 mass % or more or 20 mass % or less.

Also, the number average molecular weight of the macromonomer is preferably 500 or more and less than 8000, more preferably 800 or more and less than 7500, and still more preferably 1000 or more and less than 7000.

As the macromonomer, a general manufacturer (for example, a macromonomer manufactured by Toagosei Co., Ltd., etc.) can be used appropriately.

The high molecular weight skeleton component of the macromonomer preferably comprises an acrylic polymer or a vinyl polymer.

Examples of the high-molecular-weight skeleton component of the macromonomer include polystyrene, copolymers of styrene and acrylonitrile, poly(tert-butylstyrene), poly(α-methylstyrene), polyethylene methyl toluene, polymethyl methacrylate, etc.

As a terminal polymerizable functional group of the said macromonomer, a methacryl group, an acryl group, a vinyl group etc. are mentioned, for example.

(Physical properties of (meth)acrylic copolymer (3-A))

The complex viscosity of the above-mentioned (meth)acrylic copolymer (3-A) at a temperature of 130°C and a frequency of 0.02 Hz is preferably 100~800Pa‧s, more preferably 150~700Pa‧s, and more preferably 170~ 600Pa‧s.

The complex viscosity of the above-mentioned (meth)acrylic copolymer (3-A) at a temperature of 130°C will affect the fluidity of the adhesive resin composition when the transparent double-sided adhesive is melted and used, so if If the complex viscosity is 100~800Pa‧s, it can have excellent hot-melt suitability.

In order to adjust the complex viscosity of the (meth)acrylic copolymer (3-A) to the above range, for example, adjusting the glass transition temperature of the copolymer component constituting the main component of the graft copolymer (3-A1) can be exemplified. It can be adjusted by adjusting to -70°C to 0°C, more preferably -65°C or higher or -5°C or lower, especially preferably -60°C or higher or -10°C or lower, and adjusting the molecular weight of the copolymer component Viscoelastic method. However, it is not limited to this method.

<Crosslinking agent (3-B)>

As the cross-linking agent (3-B), for example, one having two or more cross-linking groups such as epoxy groups or isocyanate groups, oxetanyl groups, silanol groups, (meth)acryl groups, etc. can be appropriately selected. crosslinking agent. Among them, in terms of reactivity or the strength of the obtained hardened product, polyamides having 2 or more (meth)acryl groups are preferred, and polyamides having 3 or more (meth)acryl groups are more preferred. Functional (meth)acrylates or (meth)acrylates with epoxy groups, isocyanate groups, and silanol groups.

Examples of such polyfunctional (meth)acrylates include 1,4-butanediol di(meth)acrylate, glycerin di(meth)acrylate, glycerin glycidyl ether di(meth)acrylate ester, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, bisphenol A poly Ethoxylated Di(meth)acrylate, Bisphenol A Polypropoxylated Di(meth)acrylate, Bisphenol F Polyethoxylated Di(meth)acrylate, Ethylene Glycol Di(meth)acrylate , trimethylolpropane trioxyethyl (meth)acrylate, ε-caprolactone modified three (2- Hydroxyethyl) isocyanurate tri(meth)acrylate, pentaerythritol tri(meth)acrylate, propoxylated pentaerythritol tri(meth)acrylate, ethoxylated pentaerythritol tri(meth)acrylate, pentaerythritol tetra (Meth)acrylate, Propoxylated Pentaerythritol Tetra(meth)acrylate, Ethoxylated Pentaerythritol Tetra(meth)acrylate, Dipentaerythritol Hexa(meth)acrylate, Polyethylene Glycol Di(meth)acrylate , Tris(acryloxyethyl)isocyanurate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate, tripentaerythritol hexa(meth)acrylate Base) acrylate, tripentaerythritol penta(meth)acrylate, hydroxypivalate neopentyl glycol di(meth)acrylate, ε-caprolactone adduct of hydroxypivalate neopentyl glycol Di(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolpropane polyethoxy tri(meth)acrylate, bis(trimethylolpropane)tetra(methyl) ) acrylates and other UV curable polyfunctional monomers, in addition: polyester (meth)acrylate, epoxy (meth)acrylate, (meth)acrylate urethane, polyether ( Polyfunctional acrylate oligomers such as meth)acrylate or isocyanate (meth)acrylate, 1,1-(bis(meth)acryloxymethyl)ethyl isocyanate, 2-(2-( Meth)acryloxyethyloxy)ethyl isocyanate, glycidyl (meth)acrylate, glycidyl hydroxyethyl acrylate, glycidyl hydroxypropyl (meth)acrylate, (meth)acrylic acid Hydroxybutyl Glycidyl Ether.

Among those listed above, polyfunctional monomers or oligomers containing polar functional groups such as hydroxyl groups are preferred from the viewpoint of improving the adhesion to the adherend or the effect of suppressing wet heat whitening.

Among them, it is preferable to use a polyfunctional (meth)acrylate having a hydroxyl group.

Therefore, from the viewpoint of preventing wet heat whitening, it is preferable to contain a hydrophobic acrylate monomer and a hydrophilic acrylate monomer as the main component of the above-mentioned graft copolymer (3-A1). As the coupling agent (3-B), it is preferable to use a polyfunctional (meth)acrylate having a hydroxyl group.

The content of the crosslinking agent (3-B) is preferably 100% relative to the (meth)acrylic copolymer (3-A) The ratio of 0.5 to 20 parts by mass is included, more preferably at least 1 part by mass or less than 15 parts by mass, and even more preferably at least 2 parts by mass or less than 10 parts by mass.

By containing the crosslinking agent (3-B) within the above range, the shape stability of the adhesive sheet 3 in the uncrosslinked state and the foaming resistance reliability of the crosslinked adhesive can be simultaneously realized. Among them, in terms of balance with other elements, it may also exceed this range.

<Photopolymerization Initiator (3-C)>

The photopolymerization initiator (3-C) functions as a reaction initiation aid for the crosslinking reaction of the above-mentioned crosslinking agent (3-B).

As the photopolymerization initiator, conventionally known ones can be appropriately used. Among them, a photopolymerization initiator responsive to ultraviolet rays having a wavelength of 380 nm or less is preferable from the viewpoint of easy control of the crosslinking reaction.

On the other hand, a photopolymerization initiator that responds to light with a wavelength longer than 380 nm is preferable because the induced light easily reaches the deep portion of the adhesive sheet 3 .

Photopolymerization initiators are roughly divided into two categories according to the mechanism of free radical generation, roughly divided into: cleavage-type photopolymerization initiators that can break and decompose the single bond of the photopolymerization initiator itself to generate free radicals, and The photoexcited initiator and the hydrogen donor and donor in the system form an excited complex, which can transfer the hydrogen of the hydrogen donor and donor to the hydrogen abstraction type photopolymerization initiator.

Among them, the cleavage-type photopolymerization initiator decomposes into other compounds when free radicals are generated by light irradiation, and loses its function as a reaction initiator once it is excited. Therefore, it is preferable because it does not remain as an active material in the adhesive material after the crosslinking reaction is completed, and there is no possibility of causing unexpected photodegradation to the adhesive material.

On the other hand, when a hydrogen abstraction photopolymerization initiator is irradiated with active energy rays such as ultraviolet rays to generate a free radical reaction, no decomposition product such as a cracking photopolymerization initiator is generated, so it is difficult to become Volatile components can reduce the damage to the adherend, in this respect more useful.

啉基苯基)丁烷-1-酮、2-甲基-1-[4-(甲硫基)苯基]-2-

啉基丙烷-1-酮、2-(二甲胺基)-2-[(4-甲基苯基)甲基]-1-[4-(4-

啉基)苯基]-1-丁酮、雙(2,4,6-三甲基苯甲醯基)-苯基氧化膦、2,4,6-三甲基苯甲醯基二苯基氧化膦或該等之衍生物等。 Examples of the cleavage-type photoinitiator include: 2,2-dimethoxy-1,2-diphenylethan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2 -Methyl-1-phenyl-propan-1-one, 1-(4-(2-hydroxyethoxy)phenyl)-2-hydroxy-2-methyl-1-propan-1-one, 2 -Hydroxy-1-[4-{4-(2-hydroxy-2-methyl-propionyl)benzyl}phenyl]-2-methyl-propan-1-one, oligo(2-hydroxy- 2-methyl-1-(4-(1-methylvinyl)phenyl)acetone), methyl phenylglyoxylate, 2-benzyl-2-dimethylamino-1-(4-

Linylphenyl) butane-1-one, 2-methyl-1-[4-(methylthio)phenyl]-2-

Linyl propan-1-one, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-

Phenyl)phenyl]-1-butanone, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenyl Phosphine oxide or their derivatives, etc.

、2-氯-9-氧硫

、3-甲基-9-氧硫

、2,4-二甲基-9-氧硫

、2-甲基蒽醌、2-乙基蒽醌、2-第三丁基蒽醌、2-胺基蒽醌或其衍生物等。 Examples of the hydrogen abstraction type photoinitiator include: benzophenone, 4-methyl-benzophenone, 2,4,6-trimethylbenzophenone, 4-phenylbenzophenone Ketone, 3,3'-dimethyl-4-methoxybenzophenone, 4-(meth)acryloxybenzophenone, methyl 2-benzoylbenzoate, benzoyl Methyl methanoate, bis(2-phenyl-2-glyoxylate)oxybisethylene, 4-(1,3-acryloyl-1,4,7,10,13-pentaoxotridecane base) benzophenone, 9-oxosulfur

, 2-Chloro-9-oxosulfur

, 3-methyl-9-oxosulfur

, 2,4-Dimethyl-9-oxosulfur

, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-aminoanthraquinone or its derivatives, etc.

However, it is not limited to what was listed above as a photoinitiator. Any of the cleavage type photopolymerization initiators and hydrogen abstraction type photopolymerization initiators listed above may be used, or two or more of them may be used in combination.

The content of the photopolymerization initiator (3-C) is preferably contained in a ratio of 0.1 to 5 parts by mass relative to 100 parts by mass of the (meth)acrylic copolymer (3-A), more preferably 0.5 parts by mass. It is more than or equal to 3 parts by mass, and it is more preferable to contain it in the ratio of 1 part by mass or more.

Moderate reaction sensitivity to active energy rays can be obtained by making content of a photoinitiator (3-C) into the said range.

<other ingredients>

The present adhesive resin composition 3 may contain, as components other than the above, known components formulated in ordinary adhesive compositions. For example, if necessary, various types such as adhesion-imparting resins, antioxidants, photostabilizers, metal deactivators, anti-aging agents, moisture absorbers, polymerization inhibitors, ultraviolet absorbers, rust inhibitors, silane coupling agents, and inorganic particles can be appropriately contained. additive.

Moreover, a reaction catalyst (tertiary amine type compound, quaternary ammonium type compound, tin laurate compound, etc.) may be contained suitably as needed.

<Features of this adhesive sheet 3>

The present adhesive sheet 3 may be an adhesive sheet that can maintain a sheet shape under normal conditions, has heat-melt property that melts or flows when heated in an uncrosslinked state, and has photocurable property that can be photocured.

If the sheet can be kept in a normal state, it is easier to handle than a liquid adhesive, and the work of filling the liquid can be omitted, so the productivity is particularly excellent. At this time, if it has moderate adhesiveness in the normal state, that is, around room temperature, that is, the property of sticking to the adherend with a light force for a short time (called "stickiness"), it will be easy to stick. Positioning and workability are excellent, so it is better to have viscosity in the normal state, that is, around room temperature, and it is better if it also has viscosity in the lower temperature range from -5°C to 20°C. Such tackiness can be obtained by using the above-mentioned graft copolymer (3-A1) as the (meth)acrylic copolymer (3-A).

In addition, if it has a hot-melt property that melts or flows when heated, it can be softened or fluidized by heating, and the adhesive can be filled with uneven parts such as printing steps, so it can be used without foaming. filling.

Furthermore, if it has photocurability, it can stick firmly by finally photocuring it.

As mentioned above, in order to produce a photohardenable adhesive sheet that can maintain a sheet shape under normal conditions, has a heat-melt property that melts or flows when heated in an uncrosslinked state, for example, if it is a single-layer adhesive sheet material, it is only necessary to make a single-layer adhesive sheet from the above-mentioned adhesive resin composition 3. On the other hand, in the case of making a multi-layered adhesive sheet, for example, two types 2 in which an adhesive layer composed of this adhesive resin composition 3 and an adhesive layer composed of another adhesive resin composition are laminated. Layer structure, or two types of 3-layer structure in which an adhesive layer containing this adhesive resin composition 3 is arranged on the front and back through an intermediate resin layer, or an adhesive layer containing this adhesive resin composition 3 and an adhesive layer containing this adhesive resin composition 3 are sequentially laminated. Three types of 3-layer structures formed by the middle layer of the resin composition and the adhesive layer of the resin composition containing other adhesives, etc.

Wherein, the adhesive resin composition used to form the adhesive sheet 3 is not limited to the adhesive resin composition 3 .

(gel fraction)

From the point of view of expressing hot-melt property in the state before photohardening, the gel fraction (a) of the adhesive sheet 3 before photohardening is 5% or less, preferably 4% or less, especially Preferably less than 2%.

Also, from the standpoint of obtaining higher cohesive force after photocuring and the reliability of foaming resistance in hot and humid environments, the gel fraction (b) of the adhesive sheet 3 after photocuring is preferably More than 50%, more preferably more than 60% or less than 90%, especially more than 65% or less than 80%.

In order to adjust the gel fraction (a) before photohardening and the gel fraction (b) after photohardening as described above, for example, a graft copolymer (A1) having a macromonomer as a branch component is used as ( The meth)acrylic copolymer (3-A) may be adjusted by adjusting the composition ratio of the crosslinking agent or photopolymerization initiator, or adjusting the temperature or light irradiation amount during processing. However, it is not limited to this method.

(tensile modulus of elasticity)

Regarding this adhesive sheet 3, if the ratio ( _{X 1} /X ₂ ) of the tensile modulus (X 1 ) before photocrosslinking to the tensile modulus (X ₂ ) after photocrosslinking becomes 3 or more, Then, good step absorption or foaming resistance reliability can be obtained.

From this point of view, the ratio (X ₁ /X ₂ ) of the tensile modulus of elasticity (X ₁ ) before photocrosslinking to the tensile modulus of elasticity (X ₂ ) after photocrosslinking is preferably 3 or more, Among them, 5 or more or 30 or less are more preferable, and 10 or more or 27 or less are still more preferable.

The tensile elastic modulus (X ₁ ) before photocrosslinking is preferably from 0.01 MPa to 0.2 MPa, more preferably from 0.05 MPa to 0.1 MPa.

On the other hand, the tensile elastic modulus (X ₂ ) after photocrosslinking is preferably from 0.8 MPa to 2.0 MPa, more preferably from 1.0 MPa to 1.8 MPa.

(Maximum tensile stress (Y))

Regarding this adhesive sheet 3, if the ratio (Y ₁ /Y ₂ ) of the maximum tensile stress (Y ₁ ) before photocrosslinking to the maximum tensile stress (Y ₂ ) after photocrosslinking is 5 or more and 20 or less , you can get good step absorption or anti-foaming reliability.

From this viewpoint, the ratio (Y ₁ /Y ₂ ) of the maximum tensile stress (Y ₁ ) before photocrosslinking to the maximum tensile stress (Y ₂ ) after photocrosslinking of the present adhesive sheet 3 is preferable 5 or more and 20 or less, and more preferably 8 or more or 15 or less.

The maximum tensile stress (Y ₁ ) before photocrosslinking is preferably not less than 0.5N and not more than 5N, particularly preferably not less than 0.8N and not more than 2N.

On the other hand, the maximum tensile stress (Y ₂ ) after photocrosslinking is preferably not less than 7N and not more than 15N, particularly preferably not less than 9N and not more than 12N.

(tensile stress at break (Z))

Regarding this adhesive sheet 3, if the ratio (Z ₁ /Z ₂ ) of the tensile breaking stress (Z ₁ ) before photocrosslinking to the tensile breaking stress (Z ₂ ) after photocrosslinking is 10 or more and 50 or less , you can get good step absorption or anti-foaming reliability.

From this point of view, the ratio (Z ₁ /Z ₂ ) of the tensile breaking stress before photocrosslinking (Z ₁ ) to the tensile breaking stress (Z ₂ ) after photocrosslinking of the present adhesive sheet 3 is preferable It is 10 or more and 50 or less, especially preferably 15 or more or 40 or less.

The tensile breaking stress (Z ₁ ) before photocrosslinking is preferably from 0.1N to 2N, particularly preferably from 0.2N to 0.6N.

On the other hand, the tensile breaking stress (Z ₂ ) after photocrosslinking is preferably not less than 7N and not more than 16N, particularly preferably not less than 9N and not more than 12N.

In this adhesive sheet 3, in order to adjust the tensile elastic modulus, maximum tensile stress and tensile breaking stress within the above ranges, for example, a graft copolymer (3- A1) As the (meth)acrylic copolymer (3-A), the type or number of parts of the macromonomer may be adjusted. However, it is not limited to this method.

If a graft copolymer (3-A1) having a macromonomer as a branch component is used as the (meth)acrylic copolymer (3-A), the shape of the sheet can be maintained under normal conditions. It can exert fluidity and meet the step followability, and the hardening reaction can be promoted by ultraviolet crosslinking to obtain excellent bonding reliability.

<Laminated structure>

The adhesive sheet 3 may be a sheet comprising a single layer, or a multi-layer sheet formed by laminating two or more layers.

When the present adhesive sheet 3 is made into a multi-layer transparent double-sided adhesive material, the outermost layer is preferably the same as the case of the above-mentioned single layer, and at the same time realizes concave-convex followability and foam resistance reliability. Preferably, it is molded using the present adhesive resin composition 3 described above.

On the other hand, since the intermediate layer does not contribute to the adhesion with the constituent members of the image display device, it is preferable not to impair the transparency, and to have light transmittance to the extent that the secondary curing reaction of the outermost layer is not hindered. And it has the property of improving reduction and handling.

The type of the base polymer forming the intermediate layer is not particularly limited as long as it is a transparent resin. The base polymer forming the middle layer may be the same resin as the base polymer of the outermost layer or a different resin. Among them, it is preferable to use the same acrylic resin as the base polymer of the outermost layer from the viewpoint of ensuring transparency, ease of manufacture, and preventing refraction of light at the boundary surface of the laminate.

The intermediate layer and other resin layers may or may not have active energy ray curability. For example, it may be cured by ultraviolet crosslinking, or it may be cured by heat. In addition, in particular, post-hardening may not be performed. Among them, in consideration of the adhesiveness with the outermost layer, it is preferably formed so as to be post-cured, and particularly preferably formed so as to be ultraviolet crosslinked.

At this time, as the content of the crosslinking initiator increases, the light transmittance decreases, so it is preferable to contain the ultraviolet crosslinking agent at a lower content of the crosslinking initiator in the middle layer than in the outer layer.

When this adhesive sheet 3 is made into a multi-layered transparent double-sided adhesive, as a laminated structure, specifically, two types 2 in which this adhesive resin composition 3 and another adhesive resin composition are laminated are listed. Layer structure, or two types of three-layer structure in which this adhesive resin composition 3 is arranged on the front and back through an intermediate resin layer, or this adhesive resin composition 3, intermediate resin composition, and other adhesive resin combinations are laminated sequentially There are three kinds of three-layer structures made of things.

In addition, this adhesive resin composition 3 and other adhesive resin compositions can be molded in a sheet form on different release films or image display device constituent members, and both adhesive surfaces can be laminated to obtain this adhesive sheet 3, In addition, the present adhesive composition 3, the intermediate resin composition and the adhesive can also be used in sequence. The resin composition is co-extruded to obtain the adhesive sheet 3 of two types and three layers. In addition, the adhesive composition 3 or other adhesive resin compositions can be laminated on the front and back of the middle resin layer to obtain the adhesive sheet. Material 3.

Also, for example, it may be a substrate-attached adhesive sheet having a structure in which the above-mentioned adhesive layer 3 is formed on a substrate, or may be a substrate-less adhesive sheet that does not have a substrate. Furthermore, it may be a double-sided adhesive sheet having the above-mentioned present adhesive layer 3 on both upper and lower sides, or a single-sided adhesive sheet having the above-mentioned present adhesive layer 3 only on one side of the upper and lower sides.

<thickness>

The thickness of the adhesive sheet 3 , that is, the total thickness is preferably 50 μm to 1 mm, more preferably 75 μm or more or 500 μm or less from the viewpoint of not hindering the thinning of the image display device and the viewpoint of step absorption.

If the total thickness of the adhesive sheet 3 is 50 μm or more, it can follow unevenness such as high printing steps, and if it is 1 mm or less, it can meet the requirement of thinning.

Furthermore, the thickness of the adhesive sheet 3 is preferably 75 μm or more from the viewpoint that the printing height of the concealing layer on the periphery of the conventional image display device is higher, specifically, a level difference of about 80 μm can be filled. More preferably, it is 100 μm or more. On the other hand, it is preferably 500 μm or less, particularly preferably 350 μm or less, from the viewpoint of meeting the demand for thinning.

Also, the thickness of the maximum thickness portion is preferably at least 5 μm, more preferably at least 10 μm, and still more preferably at least 15 μm, from the viewpoint of not hindering the adhesion with the adherend or shock absorption.

In the case of a multilayer structure, the ratio of the thickness of each outermost layer to the thickness of the middle layer is preferably 1:1 to 1:20, more preferably 1:2 to 1:10.

If the thickness of the intermediate layer is within the above range, there will be no impact on the thickness of the adhesive layer of the laminate. It is better to give too much influence, and it will not be too soft to make the workability of cutting or handling worse.

Moreover, if the outermost layer is within the above range, the conformability to uneven or curved surfaces will not be deteriorated, and the adhesion and wettability to the adherend can be maintained, which is preferable.

In addition, the thickness of the maximum thickness portion of the present adhesive sheet 3 is preferably 250 μm or less. In other words, the adhesive sheet 3 can be a sheet with a uniform thickness, or a non-uniform sheet with parts of different thicknesses. In the case of a sheet with non-uniform thickness, the thickness of the thickest part is preferably 250 μm or less .

<purpose>

This adhesive sheet 3 can be used in its original form, and can also be used in the following manner. However, the utilization method of the adhesive sheet 3 is not limited.

(adhesive sheet laminate)

This adhesive sheet 3 can be provided, for example as an adhesive sheet laminate including a release film on one side of this adhesive sheet 3 or a double-layered release film.

(Laminate 3 for constituting the present image display device)

As an example of the use of this adhesive sheet 3, a laminated body for image display device (hereinafter referred to as a laminate) having a structure in which two constituent members for an image display device are laminated with this adhesive sheet 3 interposed can be produced. "Laminate 3 for constituting the present image display device").

The laminated body 3 for constituting an image display device includes, for example, a laminated body for constituting an image display device that includes at least two constituting members for an image display device facing each other, and at least one of the constituting members for an image display device is bonded together. The surface has an opaque portion and a light-transmitting portion; it has a structure in which the adhesive sheet 3 is filled between the above-mentioned two constituent members for an image display device; The adhesive sheet is irradiated with light to partially light-harden the adhesive sheet.

In this case, the gel fraction of the position of the above-mentioned adhesive sheet in contact with the above-mentioned light-transmitting part may be more than 50%, and the gel fraction of the position in contact with the above-mentioned opaque part may be less than 5%.

Here, as the constituent member for the above-mentioned image display device, any one of the group consisting of a touch panel, an image display panel, a surface protection panel, and a polarizing film, or a laminate including a combination of two or more .

As an example of the laminate 3 for constituting the image display device, in addition to the laminate including the protective panel/this adhesive sheet 3/polarizing film, for example: image display panel/this adhesive sheet 3/touch panel Panel, image display panel/this adhesive sheet 3/protective panel, image display panel/this adhesive sheet 3/touch panel/this adhesive sheet 3/protective panel, polarizing film/this adhesive sheet 3/touch Control panel, polarizing film/adhesive sheet 3/touch panel/adhesive sheet 3/protective panel.

The protection panel and the image display panel may also be those in which a touch panel sensor is incorporated in the protection panel or the image display panel itself.

The laminate 3 for constituting an image display device can be manufactured, for example, through the following steps (1) to (3).

Here, the manufacturing method of the laminated body 3 for constituting an image display device should only have at least the following steps (1) to (3), so other steps may be added or inserted between each step.

(1) Prepare an adhesive resin composition containing a (meth)acrylic copolymer (3-A), a crosslinking agent (B) and a photopolymerization initiator (C), and mold the adhesive resin composition into Single-layer or multi-layer sheet, the steps of making this adhesive sheet 3.

(2) A step of laminating two image display device constituent members through the adhesive sheet 3 .

(3) A step of irradiating the adhesive sheet 3 with active energy rays on the outside of at least one of the image display device constituent members to crosslink the present adhesive sheet 3 and bond the two image display device constituent members.

(step 1))

In step (1), the present adhesive resin composition 3 is prepared by a known method, and formed into a single-layer or multi-layer uncrosslinked sheet with an adhesive layer comprising the adhesive resin composition to produce this adhesive resin composition. Adhesive sheet 3.

As a method for forming the present adhesive resin composition 3 into a sheet shape, conventionally known methods can be arbitrarily adopted.

At this time, the present adhesive resin composition 3 can also be formed into a single-layer or multi-layer sheet on a release film to produce a single-layer or multi-layer transparent double-sided adhesive material with an adhesive layer.

In addition, the present adhesive resin composition 3 can also be formed into a single-layer or multi-layer sheet on the image display device component, thereby producing a single-layer or multi-layer sheet having an adhesive layer on the image display device component. Transparent double-sided adhesive material.

(step (2))

In step (2), two image display device constituent members can be laminated by adhering the above-mentioned adhesive sheet 3 .

At this time, if the above-mentioned graft copolymer (A1) is used as the base polymer of the adhesive sheet 3, in the normal state, that is, at room temperature, the macromonomers aggregate to form a physically cross-linked structure, which can be used in this adhesive sheet. The adhesive sheet 3 imparts excellent storage stability and cutting processability.

Also, if the (meth)acrylic copolymer (3-A) has a complex viscosity of 100-800 Pa‧s at a temperature of 130°C and a frequency of 0.02 Hz, it can enjoy Excellent workability.

Thus, in step (2), two image display device constituent members can be laminated by adhering through this adhesive sheet 3 . In this way, only by pressing the adhesive sheet 3 against the adherend can simply obtain the adhesiveness of the adhesive level, so it is easy to position the adhesive material, and it is very convenient in operation profit.

In addition, the adhesive sheet 3 has excellent shape retention and can be pre-processed into any shape in advance. Therefore, the adhesive sheet 3 formed on the release film can also be processed in advance according to the size of the components of the image display device to be laminated. tailoring.

The cutting method at this time is usually punching with a Thomson knife, cutting with a super cutter or laser, and it is better to use either the release film on the front and the back in a way that is easy to peel off the release film. Borders are left and half cropped.

In step (2), the adhesive sheet 3, that is, the transparent double-sided adhesive material is also in an uncrosslinked state.

(step (3))

In step (3), active energy rays are irradiated to the above-mentioned adhesive layer of the adhesive sheet 3 from the outside of at least one of the image display device constituent members to cross-link the adhesive layer and bond the two image display device constituent members. , and thus the laminated body 3 for constituting the image display device can be manufactured.

This adhesive sheet 3 contains a crosslinking agent (B) and a photopolymerization initiator (C). Therefore, the above-mentioned adhesive layer of this adhesive sheet 3 is irradiated with active energy rays to crosslink and harden the adhesive layer, and 2 The components of the image display device are firmly attached.

At this time, as the active energy ray, it is sufficient to irradiate the energy ray that induces the polymerization initiator, such as heat rays, X-rays, electron beams, ultraviolet rays, and visible rays. Among them, from the viewpoint of suppressing damage to constituent members of an image display device or easiness of reaction control, irradiation with ultraviolet rays, especially ultraviolet rays with a wavelength of 380 nm or less is preferred.

There are no particular restrictions on the ultraviolet irradiation conditions. From the standpoint of maintaining workability and fully advancing the crosslinking reaction, for example, it is preferable to irradiate so that the cumulative light intensity of ultraviolet rays reaching the adhesive material becomes 500 to 5000 mJ/cm ² at a wavelength of 365 nm.

Among them, when ultraviolet rays are irradiated, the components of the image display device interrupted by blocking the above-mentioned wavelengths In the case of light, it is better to match the components of the spacer, and adjust the type of energy rays sensed by the adhesive according to the type of polymerization initiator.

(additional steps)

A step of heating the laminate obtained in the above step (2) to heat and melt the adhesive layer of the transparent double-sided adhesive material may be inserted between the above step (2) and the above step (3). That is, the laminate attached in step (2) can be heated to heat-melt (hot-melt) the adhesive layer of the present adhesive sheet 3 .

In this adhesive sheet 3, when heated, the above-mentioned aggregation of macromonomers can be disintegrated, and the physical cross-linked structure can be released to express high fluidity. Therefore, when the adhesive surface has unevenness such as printing steps, when laminating two image display device components, the adhesive sheet 3 can be heated to make it flow (heat-melt), and the unevenness followability of the adhesive can be improved. Or the wettability of the adherend can leave no strain and make the components more firmly integrated.

At this time, it is preferable to heat to 60-100 degreeC and heat-melt it. If it is 60° C. or higher, the fluidity of the adhesive material can be sufficiently imparted, and the adhesive resin composition can be sufficiently filled into the concavo-convex portion. On the other hand, if the temperature is below 100°C, not only thermal damage to the components of the image display device as the adherend can be suppressed, but also overflow or collapse of the adhesive resin composition caused by excessive fluidity of the adhesive can be prevented.

From this point of view, the hot-melt temperature is preferably 60 to 100°C, more preferably 62°C or higher or 95°C or lower, and even more preferably 65°C or higher or 90°C or lower.

(this image display device 3)

An image display device (hereinafter referred to as "this image display device 3") can also be configured using the adhesive sheet 3 or the above-mentioned image display device constituting laminate.

For example, the image display device 3 can include an image display device that includes at least two face-to-face constituent members for an image display device, and at least one of the constituent members for an image display device The material has an opaque portion and a light-transmitting portion on the bonding surface, and has a structure in which an adhesive sheet is filled between the above-mentioned two constituent members for an image display device. In this case, the gel fraction of the position of the above-mentioned adhesive sheet in contact with the above-mentioned light-transmitting part may be more than 50%, and the gel fraction of the position in contact with the above-mentioned opaque part may be less than 5%.

In the above-mentioned laminated body 3 for constituting the image display device and the image display device 3, the bonded surface has a portion that does not transmit light of a wavelength required for light hardening such as the printed portion around the screen (referred to as “in the present invention”). A component member for an image display device that is the “opaque portion”) and a portion through which light of a wavelength required for photocuring (referred to as a “transmittance portion” in the present invention) is bonded to other component members for an image display device. When appropriate, make the gel fraction of the position in contact with the above-mentioned opaque part less than 1%, and the gel fraction of the position in contact with the above-mentioned light-transmitting part is more than 40%, so as to alleviate the problem caused by the opacity. The stress borne by the light part can reduce the strain generated by the part, and it can also have a higher cohesive force so that the adherends can be firmly bonded to each other.

One example of a specific example of a preferable manufacturing method of the present image display device 3 will be described.

First, the adhesive sheet 3 is heated to be thermally fused, and the constituent members for the image display device having the printed portion, that is, the opaque portion, and the constituent members for the image display device are laminated through the adhesive sheet 3 . At this stage, since the present adhesive sheet 3 is moderately soft, it can fully follow a step difference while maintaining storage stability.

Then, light such as ultraviolet rays is irradiated from the outside of the constituent member for an image display device. Therefore, because the printed part blocks the light, the light cannot reach the part that is in contact with the printed part, or the light that reaches is significantly restricted. It can undergo cross-linking reaction and light curing, and can achieve excellent peeling resistance and foaming resistance.

As the constituent members for the above two image display devices, for example, LCDs such as computers, mobile terminals (PDAs), game machines, televisions (TVs), car navigations, touch panels, and handwriting tablets, A component of an image display device such as a PDP or EL. More specifically, for example, any one of the group consisting of a touch panel, an image display panel, a surface protection panel, and a polarizing film, or a laminate including a combination of two or more thereof can be used.

[Explanation of sentences, etc.]

Generally, the so-called "sheet", according to the definition in JIS, refers to a thinner and flat product whose thickness is smaller than the length and width. Thin and flat products with arbitrarily limited thickness are usually supplied in the form of rolls (Japanese Industrial Standard JISK6900). However, the boundary between a sheet and a film is not certain, and it is not necessary to distinguish the two in terms of language in the present invention. Therefore, in the present invention, a "film" also includes a "sheet", and it is called a "sheet". In the case of "material", "film" is also included.

In addition, when expressing a "panel" such as an image display panel and a protective panel, it includes a board, a sheet, a film, or a laminate of these.

In this specification, when described as "X~Y" (X, Y are arbitrary numbers), unless otherwise specified, it means "more than X and less than Y", and also includes "preferably greater than X" or The meaning of "preferably less than Y".

Also, when it is described as "more than X" (X is an arbitrary number), it includes the meaning of "preferably greater than X" unless otherwise specified, and when it is described as "below Y" (Y is an arbitrary number) When , it includes the meaning of "preferably smaller than Y" unless otherwise specified.

[Example]

Hereinafter, it will be further described in detail with examples. But the present invention is not limited by any of these.

[Example 1-1]

Uniformly mix 15 parts by mass (18 mol%) of polymethyl methacrylate macromonomer (Tg: 105°C) with a number average molecular weight of 2400 and propylene as a (meth)acrylic copolymer (1-A) An acrylic copolymer (1-A-1) obtained by random copolymerization of 81 parts by mass (75mol%) of butyl ester (Tg: -55°C) and 4 parts by mass (7mol%) of acrylic acid (Tg: 106°C) (weight average molecular weight: 230,000) 1 kg, 75 g of glycerol dimethacrylate (manufactured by NOF Corporation, product name: GMR) (1-B-1) as a crosslinking agent (1-B), and 75 g as a photopolymerization A mixture of 2,4,6-trimethylbenzophenone and 4-methylbenzophenone as an initiator (1-C) (manufactured by Lanberti, product name: Esacure TZT) (1-C-1 ) 15g to make adhesive composition 1-1.

The above-mentioned composition 1-1 was used as two release films, that is, two polyethylene terephthalate films ("DIAFOIL MRV-V06" manufactured by Mitsubishi Plastics Co., Ltd., thickness 100 μm) and "DIAFOIL MRQ", with a thickness of 75 μm), and shaped into a sheet using a laminating machine so as to have a thickness of 150 μm to produce an adhesive sheet 1-1 (thickness 150 μm).

Prepare a glass plate with a printed step. The glass plate is printed with a thickness of 60 μm and does not pass through ultraviolet light on the peripheral part of the glass (long side 20 mm, short side 17 mm) of 238 mm x 182 mm x thickness 0.8 mm. The upper part is 198mm×148mm.

Peel off one of the release films of the adhesive sheet 1-1, and roll it onto the soda-lime glass of 150mm×200mm×thickness 1mm.

Then, peel off the remaining release film, and use a vacuum press to press and crimp the printed surface of the glass plate with printed steps in such a way that the four sides of the adhesive surface cover the printed steps (absolute pressure 5kPa, Temperature 80°C, pressurized pressure 0.04MPa), and autoclave treatment (80°C, gauge pressure 0.2MPa, 20 minutes) for final sticking. From the printed glass side, ultraviolet rays with a wavelength of 365nm and 2000mJ/cm ² were irradiated to the adhesive sheet 1-1 by a high-pressure mercury lamp so that the adhesive sheet 1-1 was hardened to produce a laminate 1-1.

[Example 1-2]

Homogenously mix 2-ethylhexyl acrylate as (meth)acrylic copolymer (1-A) (Tg: -70°C) 55 parts by mass (36mol%) and vinyl acetate (Tg: 32°C) 40 parts by mass (56mol%) and acrylic acid (Tg: 106°C) 5 parts by mass (8mol%) random copolymerization Formed acrylic copolymer (1-A-2) (weight average molecular weight: 170,000) 1kg, ε caprolactone modified isocyanuric acid triacrylate ( 1-B-2) (manufactured by Shin Nakamura Chemical Co., Ltd., product name: A9300-1CL) 75 g and Esacure KTO46 (1-C-2) (manufactured by Lanberti) as a photopolymerization initiator (1-C) 5 g, Adhesive composition 1-2 was produced.

The above-mentioned composition 1-2 was shaped into a sheet in the same manner as in Example 1-1 to prepare an adhesive sheet 1-2 (thickness: 150 μm).

Except having used the adhesive sheet 1-2, the laminated body 1-2 was produced in the same manner as Example 1-1.

[Example 1-3]

Uniformly mix 10 parts by mass (17mol%) of polymethyl methacrylate macromonomer (Tg: 105°C) with a number average molecular weight of 1400 as a (meth)acrylic copolymer (1-A) and acrylic acid 2- 1 kg of acrylic copolymer (1-A-3) (weight average molecular weight: 230,000) obtained by random copolymerization of 90 parts by mass (83 mol%) of ethylhexyl ester (Tg: -70°C) as a crosslinking agent Propoxylated pentaerythritol triacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., product name: ATM-4PL) (1-B-3) 50 g of (1-B), and 4-4 as a photopolymerization initiator (1-C) Methyl benzophenone (1-C-3) 15g, make adhesive composition 1-3.

The above-mentioned composition 1-3 was shaped into a sheet in the same manner as in Example 1-1, and an adhesive sheet 1-3 (thickness 150 μm) was produced.

Except having used the adhesive sheet 1-3, the laminated body 1-3 was produced in the same manner as Example 1-1.

[Example 1-4]

Uniformly mix 12 parts by mass (19mol%) of polymethyl methacrylate macromonomer (Tg: 105°C) with a number average molecular weight of 2400 as a (meth)acrylic copolymer (1-A) and acrylic acid 2- Acrylic copolymer (1-A-4 ) (weight average molecular weight: 80,000) 1 kg, glycerin dimethacrylate (manufactured by NOF Corporation, product name: GMR) (1-B-1) 90 g as a crosslinking agent (1-B), and 90 g as a photo 5 g of Esacure KTO46 (1-C-2) (manufactured by Lanberti) as a polymerization initiator (1-C) was used to prepare adhesive composition 1-4.

The above-mentioned composition 1-4 was shaped into a sheet in the same manner as in Example 1-1, and an adhesive sheet 1-4 (thickness 150 μm) was produced.

Except having used the adhesive sheet 1-4, the laminated body 1-4 was produced in the same manner as Example 1-1.

[Comparative Example 1-1]

In a manner corresponding to the embodiment of WO2012/032995A, the laminate 5 was produced as follows.

In (meth)acrylic copolymer (1-A), 75 parts by mass (57mol%) of 2-ethylhexyl acrylate (Tg: -70°C) and 20 parts by mass of vinyl acetate (Tg: 32°C) Part (33mol%) and 5 parts by mass (10mol%) of acrylic acid (Tg: 106°C) were randomly copolymerized into 1 kg of acrylic copolymer (1-A-5), mixed and added as a crosslinking agent (1- B) 200g of trimethylolpropane triacrylate (1-B-4) and 10g of 4-methylbenzophenone (1-C-3) as photopolymerization initiator (1-C), prepared Resin composition for an intermediate layer. The resin composition for the intermediate layer was interposed between two peeled polyethylene terephthalate films (manufactured by Panac, NP75Z01, thickness 75 μm/manufactured by Toyobo Co., Ltd., E7006, thickness 38 μm), with a thickness of Shaped into a sheet with a thickness of 80 μm, the intermediate layer sheet (α) was produced.

Next, add and mix 20 g of 4-methylbenzophenone (1-C-3) as a photopolymerization initiator (1-C) to 1 kg of the above-mentioned acrylic copolymer (1-A-5) to prepare an adhesive layer Use a resin composition.

The resin composition for the adhesive layer is used as two release films, that is, two polyethylene terephthalate films ("DIAFOIL MRA" manufactured by Mitsubishi Plastics Co., Ltd., thickness 75 μm/"E7006" manufactured by Toyobo Co., Ltd.) , thickness 38 μm) sandwiched, and formed into a sheet shape so that the thickness becomes 35 μm, and the resin sheet (β) for an adhesive layer was produced.

Furthermore, the resin composition for the adhesive layer was sandwiched between two peeled polyethylene terephthalate films (manufactured by Mitsubishi Plastics Corporation, DIAFOIL MRF, thickness 75 μm/manufactured by Toyobo Co., Ltd., E7006, thickness 38 μm), and It shaped into a sheet shape so that thickness might become 35 micrometers, and produced the resin sheet (β') for adhesive layers.

Sequentially peel and remove the PET film on both sides of the middle layer sheet (α), and peel off the PET film on one side of the adhesive layer resin sheet (β) and (β'), and stick the exposed adhesive surface in sequence A 3-layer adhesive sheet consisting of (β)/(α)/(β') was prepared by attaching to both surfaces of the sheet (α) for the intermediate layer.

The remaining PET film on the surface of (β) and (β') is irradiated with ultraviolet rays by a high-pressure mercury lamp in such a way that the cumulative light intensity at a wavelength of 365nm becomes 1000mJ/ ^cm2 , so that (α), (β) and (β') Ultraviolet crosslinking was carried out to produce adhesive sheets 1-5 (thickness 150 μm).

Except having used the adhesive sheet 1-5, the laminated body 1-5 was produced in the same manner as Example 1-1.

[Comparative example 1-2]

To 1 kg of a commercially available acrylic adhesive (1-A-6) (manufactured by Soken Chemical Co., Ltd., trade name "SK DYNE 1882") which is a (meth)acrylic copolymer (1-A), uniformly mix isocyanate Adhesive composition 1- 6.

The above composition 1-6 was coated on a release film with a thickness of 50 μm, that is, a peel-treated polyethylene terephthalate film (“MRF75” manufactured by Mitsubishi Plastics Co., Ltd.: thickness 75 μm) so that the thickness after drying became 75 μm ) on the release surface, the solvent was dried by heating to produce an adhesive sheet with a thickness of 75 μm.

Furthermore, the above composition 1-6 was coated on a release film, that is, a release-treated polyethylene terephthalate film ("DIAFOIL MRV-V06" manufactured by Mitsubishi Plastics Co., Ltd. On the release surface with a thickness of 100 μm), the solvent was dried by heating to produce an adhesive sheet with a thickness of 75 μm.

Adhesive sheets 1-6 (thickness 150 μm) were produced by sticking the adhesive surfaces of the two produced adhesive sheets and aging them for one week.

Prepare a glass plate with a printed step. The glass plate is printed with a thickness of 60 μm and does not pass through ultraviolet light on the peripheral part of the glass (long side 20 mm, short side 17 mm) of 238 mm x 182 mm x thickness 0.8 mm. The upper part is 198mm×148mm.

Peel off one of the release films of the adhesive sheets 1-6, and roll it onto the soda-lime glass of 150mm×200mm×thickness 1mm.

Then, peel off the remaining release film, and use a vacuum press to press and crimp the printed surface of the glass plate with printed steps in such a way that the four sides of the adhesive surface cover the printed steps (absolute pressure 5kPa, temperature 80°C, pressurized pressure 0.04MPa), and autoclave treatment (80°C, gauge pressure 0.2MPa, 20 minutes) for final bonding to produce laminates 1-6.

[Comparative example 1-3]

In a manner corresponding to the embodiment of WO2010038366, laminates 1-7 were produced as follows.

Uniformly mix 650 g of phenoxy resin (1-A-7) (manufactured by InChem, PKHH, weight average molecular weight: 52,000) as a substitute for (meth)acrylic copolymer (1-A), and 650 g of crosslinking agent (1 -1 kg of urethane polyacrylate (1-B-4) (manufactured by Negami Kogyo Co., Ltd., UN5500, weight average molecular weight: 67,000) with a carbonate skeleton as an alternative to B), and as a photopolymerization initiator (1 -C) 43 g of 1-cyclohexyl phenyl ketone (1-C-4) (manufactured by BASF, Irgacure 184) was used to prepare adhesive composition 1-7.

The above-mentioned composition 1-7 was shaped into a sheet in the same manner as in Example 1-1, and an adhesive sheet 1-7 (thickness 150 μm) was produced.

Prepare a glass plate with a printed step. The glass plate is printed with a thickness of 60 μm and does not pass through ultraviolet light on the peripheral part of the glass (long side 20 mm, short side 17 mm) of 238 mm x 182 mm x thickness 0.8 mm. The upper part is 198mm×148mm.

Peel off one of the release films of the adhesive sheets 1-7, heat it at 80°C and roll it on the soda-lime glass of 150mm×200mm×thickness 1mm.

Then, peel off the remaining release film, and use a vacuum press to press and crimp the printed surface of the glass plate with printed steps in such a way that the four sides of the adhesive surface cover the printed steps (absolute pressure 5kPa, Temperature 80°C, pressurized pressure 0.04MPa), and autoclave treatment (80°C, gauge pressure 0.2MPa, 20 minutes) for final sticking. From the side of the glass on which the printing was performed, ultraviolet rays with a wavelength of 365nm and 2000mJ/cm ² were irradiated to the adhesive sheet by a high-pressure mercury lamp to harden the adhesive sheet 1-7 to produce laminates 1-7.

[evaluate]

The adhesive sheets and laminates produced in Examples and Comparative Examples were evaluated as follows.

(viscosity measurement)

A plurality of adhesive sheets 1-1 to 1-7 prepared in the examples and comparative examples were used respectively, laminated so as to have a thickness of 1 mm to 2 mm, and punched into a circular shape with a diameter of 20 mm.

Using a rheometer (manufactured by Yinghong Seiki Co., Ltd. "MARS"), with an adhesive fixture: Φ 25mm parallel plate, strain: 0.5%, frequency: 1Hz, heating rate: 3°C/min, measure the light from 70°C to 120°C The complex viscosity of the adhesive sheet before hardening.

For the adhesive sheets 1-1~1-5 and 1-7, use a high-pressure mercury lamp to irradiate the adhesive sheets with ultraviolet rays through polyethylene terephthalate film in such a way that the cumulative light intensity at 365nm becomes 2000mJ/ ^cm2 , to harden the adhesive sheet. The hardened adhesive sheets are laminated so as to have a thickness of 1 mm to 2 mm, and are punched into circular shapes with a diameter of 20 mm.

Using a rheometer (manufactured by Yinghong Seiki Co., Ltd. "MARS"), with an adhesive fixture: Φ 25mm parallel plate, strain: 0.5%, frequency: 1Hz, heating rate: 3°C/min, measure the light from 70°C to 120°C The complex viscosity of the adhesive sheet after hardening.

(adhesion after hardening)

Peel off one of the release films of the adhesive sheets 1-1 to 1-7 produced in Examples and Comparative Examples, and attach a 50 μm PET film (manufactured by Mitsubishi Plastics Corporation, DIAFOIL T100, thickness 50 μm) as a substrate film And prepare laminated product.

After cutting the above-mentioned laminated product to a length of 150 mm and a width of 10 mm, the remaining release film was peeled off, and the exposed adhesive surface was reciprocated with a 2 kg roller, and the roller was crimped on the soda-lime glass. After performing autoclave treatment (80°C, gauge pressure 0.2MPa, 20 minutes) on the laminated product for final bonding, irradiate ultraviolet light so that the cumulative light intensity at 365nm becomes 2000mJ/ ^cm2 to harden the adhesive sheet, and cure it for 15 hours. Prepare a peel force measurement sample.

Determination of the peeling force of the above-mentioned peeling force test sample to glass when it is peeled off at a peeling angle of 180° and a peeling speed of 60mm/min under the environment of 23°C, 40%RH and 80°C, 10%RH (N/cm), obtain the adhesive force after hardening.

(adhesion before hardening)

Peel off one of the release films of the adhesive sheets 1-1 to 1-7 produced in Examples and Comparative Examples, and attach a 50 μm PET film (manufactured by Mitsubishi Plastics Corporation, DIAFOIL T100, thickness 50 μm) as a substrate film And prepare laminated product.

After cutting the above-mentioned laminated product to a length of 150 mm and a width of 10 mm, the remaining release film was peeled off, and the exposed adhesive surface was reciprocated once with a 2 kg roller to press-bond the above-mentioned adhesive sheet to the soda-lime glass.

Measure the peeling force (N/cm) of the adhesion test sample to glass when it is peeled at 23°C, 40%RH and 80°C, 10%RH at a peeling angle of 180° and a peeling speed of 60mm/min. Obtain the adhesion force before hardening.

In addition, regarding the peeling mode when peeling was carried out under the environment of 80 degreeC and 10%RH, the thing which broke coagulation was shown as "CF" in the table, and the thing which peeled at the interface was shown as "AF" in the table.

(transparency)

Peel off one of the release films of the adhesive sheets 1-1~1-7 produced in the examples and comparative examples, and roll the exposed adhesive surface onto two pieces of soda-lime glass (82mm×53mm×0.5mm thick ) was applied, autoclave treatment (80° C., gauge pressure 0.2 MPa, 20 minutes) was carried out for final bonding to prepare a laminate for optical evaluation.

About the said laminated body, the haze value based on JIS K7136 and the total light transmittance (%) based on JIS K7361-1 were calculated|required using the haze meter (Nippon Denshoku Kogyo Co., Ltd. make, NDH5000).

(suitable for business)

In the production of the above-mentioned laminated body for optical evaluation, when laminating the sheets produced in Examples and Comparative Examples on soda-lime glass, roll-bonding is carried out at 23°C and 40% of the environment, and the sheet can be bonded to the glass. If the glass plate is tightly bonded and fixed, it is marked as "○ (good)", and if the glass plate and the sheet cannot be tightly bonded at 23°C and 40% of the environment, and heat is required for roll bonding, it is marked as "× (poor)".

(outgassing analysis)

The outgassing after light irradiation in the present invention refers to the one detected by the following analysis method.

(Outgassing method)

Using a high-pressure mercury lamp, for the adhesive sheets 1-1 to 1-5 and 1-7 produced in the examples and comparative examples, the cumulative light intensity at 365nm becomes 2000mJ/cm ² , through polyethylene terephthalate The ester film irradiates ultraviolet rays to the adhesive sheet to produce an adhesive sheet equivalent to photohardening. Cut the light-cured adhesive sheet into 1cm×3cm, put it into a 20ml vial and seal it tightly. This vial was placed in a xenon UV irradiation device (SUNTEST CPS: manufactured by Toyo Seiki), and UV irradiation treatment was performed at a temperature of 60° C. for 24 hours at an illuminance of 765 W/m ² .

Cut the adhesive sheet 1-6 of Comparative Example 1-2 into 1 cm×3 cm, put it into a 20 ml vial and seal it. This vial was placed in a xenon UV irradiation device (SUNTEST CPS: manufactured by Toyo Seiki), and UV irradiation treatment was performed at a temperature of 60° C. for 24 hours at an illuminance of 765 W/m ² .

(Outgassing analysis method)

Gas generation from the resin composition subjected to UV treatment as described above can be measured by gas chromatography (HS-GC) equipped with a headspace sampler.

(1) Capture of analytical gas

Gas generated from the above-mentioned adhesive sheet was collected under the following conditions.

1. HS sampler: TuboMatri×40 (manufactured by Perkin Elmer)

2. Heating temperature: 80°C

3. Heating time: 30 minutes

4. Needle temperature: 110°C

5. Transfer temperature: 170°C

6. Injection time: 0.1 minute

7. Column pressure: 16.0psi

(2) GC analysis

The generated gas was analyzed by GC (manufactured by Perkin Elmer: Clarus 580), and the detected amount of outgassing was quantified in terms of hexadecane.

(concave-convex absorptivity)

Visually observe the laminates 1-1 to 1-7 produced in the examples and comparative examples, judge as "× (poor)" if the adhesive material does not follow the adhesive material near the printing step and leave air bubbles, and judge it as "× (poor)" if the adhesive material near the step is not followed. The unevenness of the residual strain of the adhesive sheet was judged as "△", and the case of smooth bonding without air bubbles was judged as "○ (good)".

(reliability against foaming)

Put the laminates 1-1 to 1-7 produced in Examples and Comparative Examples into a xenon UV irradiation device (SUNTEST CPS: manufactured by Toyo Seiki) for observation, and perform UV irradiation treatment for 24 hours at an illumination intensity of 765W/m ² and a temperature of 60°C after appearance.

Those with bubbles with a diameter of 5 mm or more in the adhesive sheet were judged as "× (bad)", those with visible bubbles with a diameter of 5 mm or less were judged as "△ (normal)", and those with no foaming and no change in appearance were judged as " ○ (good)".

(investigation)

The peeling mode of the adhesive sheets produced in Examples 1-1 to 1-4 at high temperature before photohardening is cohesion failure, so it can be seen that the wettability to the surface to be adhered is excellent, and the followability to the uneven surface is excellent, not only In this way, the adhesive force after light hardening is also higher. Therefore, using the adhesive sheets produced in Examples 1-1 to 1-4, even under severe environmental tests such as long-term ultraviolet radiation at high temperatures, no peeling, foaming, or deformation can be obtained. A laminate with high reliability.

In addition, the adhesive sheets produced in Examples 1-1 to 1-4 can maintain their shape at 0 to 40° C. and exhibit self-adhesiveness.

The adhesive sheet of Comparative Example 1-1 is partially crosslinked by ultraviolet irradiation, that is, the state after photohardening, so when it is laminated with glass with printed steps, it can be seen near the printed steps. The residual strain of the adhesive sheet causes unevenness and poor bonding appearance. In addition, after photocuring again, the adhesive force is low and the cohesive force is poor, so foaming can be seen in the ultraviolet irradiation test, and the bonding reliability is also poor.

In Comparative Example 1-2, the cross-linking reaction of the adhesive resin composition was completed in the stage before bonding to the member, so the viscosity or adhesive force did not change even when ultraviolet rays were irradiated. Also, when laminated with glass with printed steps, some adhesive was not completely filled near the corners where the printed steps intersected, resulting in air bubbles remaining. Also, due to the strain of the adhesive material near the step difference, the growth of bubbles can be seen in the ultraviolet irradiation test.

Comparative Example 1-3 is a hot-melt adhesive sheet using an adhesive resin composition with a certain degree of rigidity at room temperature without using a (meth)acrylic copolymer as a main component.

The adhesive force of the sheets of Comparative Examples 1-3 before photohardening is low, because it can be seen that compared with the adhesive sheets of Examples, the viscosity around room temperature is very low, and the self-adhesiveness at 0-40°C is not sufficient . The adhesive sheets of Comparative Examples 1-3 have to preheat the adherend at the stage of self-positioning during lamination. Compared with the adhesive sheets that can be attached at room temperature only by crimping, there is a defect that the operation is complicated.

[Example 2-1]

Uniformly mix 15 parts by mass (18 mol%) of a macromonomer with a number average molecular weight of 2900 including polymethyl methacrylate (Tg: 105°C) and acrylic acid as a (meth)acrylic copolymer (2-A). Acrylic graft copolymer (2-A-1 ) (weight average molecule Quantity: 230,000) 1 kg, glycerin dimethacrylate (manufactured by NOF Corporation, product name: GMR) (2-B-1) 90 g as a crosslinking agent (2-B), and as a photopolymerization initiator (2-C) a mixture of 2,4,6-trimethylbenzophenone and 4-methylbenzophenone (manufactured by Lanberti, product name: Esacure TZT) (2-C-1) 15g, Adhesive resin composition 2-1 was prepared.

A peeled polyethylene terephthalate film Y (manufactured by Mitsubishi Plastics Corporation, DIAFOIL MRV-V06, thickness 100 μm, called "release film Y") and a peeled polyethylene terephthalate film Ester film Z (manufactured by Mitsubishi Plastics Co., Ltd., DIAFOIL MRQ, thickness 75 μm, called “release film Z”) sandwiches the above-mentioned composition 2-1, and forms it into a sheet with a laminating machine so that the thickness becomes 150 μm. Adhesive sheet X1 (thickness 150 μm).

Attach a double-sided tape to one side of a black sheet (LSL-8 Inoac company with a light transmittance of 0%) and cut it to 50mm×100mm, and stick it to the mold release laminated on one side of the above-mentioned adhesive sheet X1 An opaque portion is formed on the surface of the film Z, and an adhesive sheet laminate having a light-transmitting portion and an opaque portion on the surface of the sheet is produced.

Next, using a high-pressure mercury lamp, ultraviolet rays are irradiated from the black sheet side of the adhesive sheet laminate produced in this way so that the cumulative light intensity at a wavelength of 365 nm becomes 2000 mJ/cm ² to harden the light-transmitting portion of the adhesive sheet laminate to produce Adhesive sheet 2-1 having a soft part and a hard part.

(Refer to Figure 2)

Here, the so-called soft portion refers to the portion of the adhesive sheet covered by the black sheet, and the so-called hard portion refers to the portion of the adhesive sheet not covered by the black sheet.

[Example 2-2]

Uniformly mix 55 parts by mass (36mol%) of 2-ethylhexyl acrylate (Tg: -70°C) and 40% of vinyl acetate (Tg: 32°C) as a (meth)acrylic copolymer (2-A). An acrylic system made by random copolymerization of 5 parts by mass (56mol%) and 5 parts by mass (8mol%) of acrylic acid (Tg: 106°C) Copolymer (2-A-2) (weight average molecular weight: 170,000) 1kg, isocyanuric acid EO modified diacrylate and isocyanuric acid EO modified diacrylate as crosslinking agent (2-B) 70 g of a mixture (2-B-2) of permanent triacrylate (manufactured by Toagosei Co., Ltd., product name: ARONIX M313), and Esacure KTO46 (2-C-2) as a photopolymerization initiator (2-C) ( Lanberti company) 5g, and the adhesive resin composition 2-2 was produced.

The above-mentioned composition 2-2 was sandwiched between the above-mentioned release films Y and Z, and formed into a sheet shape using a laminating machine so as to have a thickness of 150 μm, thereby producing an adhesive sheet X2 (thickness 150 μm).

Except for using the adhesive sheet X2, an adhesive sheet laminate was produced in the same manner as in Example 2-1, and an adhesive sheet 2-2 having a soft part and a hard part was produced in the same manner as in Example 2-1. .

[Example 2-3]

Uniformly mix 10 parts by mass (17mol%) of polymethyl methacrylate macromonomer (Tg: 105°C) with a number average molecular weight of 1400 as a (meth)acrylic copolymer (2-A) and 2-ethyl acrylic acid 1 kg of an acrylic graft copolymer (2-A-3) (weight average molecular weight: 230,000) obtained by random copolymerization of 90 parts by mass (83 mol%) of hexyl hexyl ester (Tg: -70°C) as a cross-linking Tricyclodecane dimethacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., product name: DCP) (2-B-3) 50 g of the agent (2-B), and as the photopolymerization initiator (2-C) 15 g of a mixture of 2,4,6-trimethylbenzophenone and 4-methylbenzophenone (manufactured by Lanberti, product name: Esacure TZT) (2-C-1) to prepare adhesive resin composition 2 -3.

The above-mentioned composition 2-3 was sandwiched between the above-mentioned release films Y and Z, and formed into a sheet shape using a laminating machine so as to have a thickness of 150 μm, thereby producing an adhesive sheet X3 (thickness 150 μm).

Except for using the adhesive sheet X3, an adhesive sheet laminate was produced in the same manner as in Example 2-1, and an adhesive sheet having a soft part and a hard part was produced in the same manner as in Example 2-1. Material 2-3.

[Example 2-4]

Uniformly mix 12 parts by mass (19mol%) of polymethyl methacrylate macromonomer (Tg: 105°C) with a number average molecular weight of 2400 as a (meth)acrylic copolymer (2-A) and acrylic acid 2- Acrylic graft copolymer (2-A -4) (weight average molecular weight: 80,000) 1 kg, glycerol dimethacrylate (manufactured by NOF Corporation, product name: GMR) (2-B-1) 90 g as a crosslinking agent (2-B), and A mixture of 2,4,6-trimethylbenzophenone and 4-methylbenzophenone as a photopolymerization initiator (2-C) (manufactured by Lanberti, product name: Esacure TZT) (2- C-1) 15g, and the adhesive resin composition 2-4 was produced.

The above-mentioned composition 2-4 was sandwiched between the above-mentioned release films Y and Z, and formed into a sheet shape using a laminating machine so as to have a thickness of 150 μm, thereby producing an adhesive sheet X4 (thickness 150 μm).

Except for using the adhesive sheet X4, an adhesive sheet laminate was produced in the same manner as in Example 2-1, and an adhesive sheet 2-4 having a soft part and a hard part was produced in the same manner as in Example 2-1. .

[Example 2-5]

Uniformly mix 1 kg of the acrylic copolymer (2-A-1) (weight average molecular weight: 230,000) used in Example 2-1, trimethylolpropane triacrylate ( 2-B-4) 70 g, and a mixture of 2,4,6-trimethylbenzophenone and 4-methylbenzophenone as a photopolymerization initiator (2-C) (manufactured by Lanberti, Product name: Esacure TZT) (2-C-1) 8g, to make adhesive resin composition 2-5.

The solution obtained by diluting Adhesive Resin Composition 2-5 with ethyl acetate so that the solid content concentration becomes 40% is applied on the peeled surface so that the thickness after drying becomes 25 μm. The polyethylene terephthalate film Y (manufactured by Mitsubishi Plastics Co., Ltd., DIAFOIL MRV-V06, thickness 100 μm, called "release film Y") is dried on the peeled surface, and then applied to the coated adhesive surface The polyethylene terephthalate film Z (manufactured by Mitsubishi Plastics Co., Ltd., DIAFOIL MRQ, thickness 75 μm, called “release film Z”) was covered with a peeled polyethylene terephthalate film Z, and an adhesive sheet X5 (thickness 25 μm) was prepared.

Except for using the adhesive sheet X5, an adhesive sheet laminate was produced in the same manner as in Example 2-1, and an adhesive sheet 2-5 having a soft part and a hard part was produced in the same manner as in Example 2-1. .

[Comparative Example 2-1]

Based on 75 parts by mass (57mol%) of 2-ethylhexyl acrylate (Tg: -70°C), 20 parts by mass (33mol%) of vinyl acetate (Tg: 32°C) and 5 parts by mass of acrylic acid (Tg: 106°C) part (10mol%) random copolymerization of (meth)acrylic copolymer (2-A-5) 1kg, mixed with trimethylolpropane triacrylate (2-B-4) 200g and 4 - 10 g of methylbenzophenone (2-C-3) to prepare a resin composition for an intermediate layer.

The resin composition for the intermediate layer was interposed between two peeled polyethylene terephthalate films (manufactured by Panac, NP75Z01, thickness 75 μm/manufactured by Toyobo Co., Ltd., E7006, thickness 38 μm), with a thickness of Shaped into a sheet with a thickness of 80 μm, the intermediate layer sheet (α) was produced.

Next, 20 g of 4-methylbenzophenone (2-C-3) was added and mixed as a photopolymerization initiator (2-C) to 1 kg of the above-mentioned acrylic copolymer (2-A-5) to prepare an adhesive layer Use a resin composition.

The above resin composition for an adhesive layer was sandwiched between two peeled polyethylene terephthalate films (manufactured by Mitsubishi Plastics Corporation, DIAFOIL MRA, thickness 75 μm/manufactured by Toyobo Co., Ltd., E7006, thickness 38 μm), and It is shaped into a sheet so that the thickness becomes 35 μm, and the production Used as a resin sheet (β) for an adhesive layer.

On the other hand, the resin composition for the adhesive layer was sandwiched between two polyethylene terephthalate films (manufactured by Mitsubishi Plastics Corporation, DIAFOIL MRF, thickness 75 μm/manufactured by Toyobo Co., Ltd., E7006, thickness 38 μm) that had undergone peeling treatment. Hold, shape it into a sheet shape so that thickness may become 35 micrometers, and prepare the resin sheet (β') for adhesive layers.

Peel and remove the PET film on both sides of the middle layer sheet (α) in sequence, and peel off the PET film on one side of the adhesive layer resin sheet (β) and (β'), and stick the exposed adhesive surface sequentially A 3-layer adhesive sheet consisting of (β)/(α)/(β') was prepared by attaching to both surfaces of the sheet (α) for the intermediate layer.

The remaining PET film on the surface of (β) and (β') is irradiated with ultraviolet rays by a high-pressure mercury lamp in such a way that the cumulative light intensity at a wavelength of 365nm becomes 1000mJ/ ^cm2 , so that (α), (β) and (β') Ultraviolet crosslinking was carried out to produce an adhesive sheet X6 (thickness 150 μm).

A black sheet (LSL-8 manufactured by Inoac with a light transmittance of 0%) is affixed with double-sided tape on one side and cut to 50mm x 100mm, and attached to one of the above-mentioned adhesive sheets X6 that has been peeled off. The surface of the ethylene terephthalate film (manufactured by Mitsubishi Plastics Corporation, DIAFOIL MRF) is formed to be opaque, and an adhesive sheet laminate having a translucent portion and an opaque portion in the sheet surface is produced.

Next, using a high-pressure mercury lamp, irradiate ultraviolet rays from the black sheet side of the adhesive sheet laminate of the adhesive sheet produced in this way so that the cumulative light intensity at a wavelength of 365nm becomes 2000mJ/ ^cm2 , and the light-transmitting part of the laminate is in contact with The parts of the adhesive material are further irradiated with light to produce adhesive sheets 2-6.

[Comparative Example 2-2]

650 g of phenoxy resin (2-A-6) (manufactured by InChem, PKHH, weight average molecular weight 52,000) and polyacrylic acid having a carbonate skeleton as an alternative to the crosslinking agent (2-B) were uniformly mixed Urethane (2-B-4) (manufactured by Negami Industry Co., Ltd., UN5500, weight average molecular weight 67,000) 1 kg, 1-cyclohexyl phenyl ketone (2-cyclohexyl phenyl ketone) as photopolymerization initiator (2-C) C-4) (BASF company make, Irgacure184) 43g, and the adhesive resin composition 2-7 was produced.

The above compositions 2-7 were interposed between two peeled polyethylene terephthalate films (manufactured by Mitsubishi Plastics Corporation, DIAFOIL MRV-V06, thickness 100 μm / manufactured by Mitsubishi Plastics Corporation, DIAFOIL MRQ, thickness 75 μm) , Shaped into a sheet shape using a laminating machine so as to have a thickness of 150 μm, and an adhesive sheet X7 (thickness 150 μm) was produced.

A black sheet (LSL-8 manufactured by Inoac with a light transmittance of 0%) is pasted with double-sided tape on one side and cut to 50mm x 100mm, and attached to one of the above-mentioned adhesive sheets X7 which has been peeled off. The surface of an ethylene terephthalate film (manufactured by Mitsubishi Plastics Corporation, DIAFOIL MRQ) is formed to be opaque, and an adhesive sheet laminate having a translucent portion and an opaque portion on the surface of the sheet is produced.

Next, using a high-pressure mercury lamp, ultraviolet rays are irradiated from the black sheet side of the adhesive sheet laminate produced in this way so that the cumulative light intensity at a wavelength of 365 nm becomes 2000 mJ/cm ² to harden the light-transmitting portion of the adhesive sheet laminate to produce Adhesive sheets 2-7.

[Comparative example 2-3]

1 kg of a commercially available acrylic adhesive (2-A-7) (manufactured by Soken Chemical Co., Ltd., trade name "SK DYNE 1882") was uniformly mixed with an isocyanate-based hardener (manufactured by Soken Chemical Co., Ltd., trade name "L-45") 1.85 g and 0.5 g of an epoxy-based hardener (manufactured by Soken Chemical Co., Ltd., trade name "E-5XM") were used to prepare Adhesive Resin Composition 2-6.

The above-mentioned composition 2-6 was applied to the mold release of a release-treated polyethylene terephthalate film (trade name "MRF75": manufactured by Mitsubishi Plastics Co., Ltd.) with a thickness of 50 μm so that the thickness after drying was 75 μm. On the surface, dry the solvent by heating to make an adhesive sheet with a thickness of 75 μm material.

Furthermore, the above-mentioned composition 2-6 was coated on the release layer of a polyethylene terephthalate film (manufactured by Mitsubishi Plastics Corporation, DIAFOIL MRV-V06, thickness 100 μm) so that the thickness after drying became 75 μm. On the die surface, the solvent was dried by heating to produce an adhesive sheet with a thickness of 75 μm.

For the two produced adhesive sheets, stick to the respective adhesive surfaces and cure for 1 week to allow the hardener to react to produce adhesive sheets 2-8 (thickness 150 μm).

[evaluate]

Various physical property values of the adhesive sheets 2-1 to 2-8 produced in Examples and Comparative Examples were measured and evaluated as follows.

(gel fraction)

Take out the parts of the adhesive sheets 2-1~2-7 that are in contact with the light-transmitting part, that is, the hard part, and the part that is in contact with the opaque part, that is, the soft part, of the adhesive sheets 2-1~2-7 produced in the examples and comparative examples. Those who took out were subjected to the following measurements.

Regarding the adhesive sheet 2-8 of Comparative Example 2-3, the following measurement was performed on an arbitrary part.

1) Weigh the adhesive composition (W1) and wrap it in a 200-mesh SUS screen (W0) with a predetermined weight.

2) Immerse the above SUS mesh in 100 mL of ethyl acetate for 24 hours.

3) Take out the SUS screen and semi-dry at 75°C for 4 hours.

4) The weight (W2) after drying is obtained, and the gel fraction of the adhesive composition is determined by the following formula.

Gel fraction (%)=100×(W2-W0)/W1

(Glass transition temperature (Tg))

Using a differential scanning calorimeter (DSC-8500) manufactured by PerkinElmer, the temperature was measured according to JIS K-7121 (ISO3146) at a heating rate of 5°C/min. According to the obtained thermal spectrum, each of the adhesive sheets 2 From -1 to 2-7, the glass transition temperature (Tg) is obtained for the part that is in contact with the light-transmitting part, that is, the hard part, and the part that is in contact with the opaque part, that is, the soft part.

For the adhesive sheet 2-8 of Comparative Example 2-3, the same measurement was performed on any part.

(Ascal Hardness)

For the parts of the adhesive sheets 2-1 to 2-7 produced in the examples and comparative examples that are in contact with the opaque part, that is, the soft part, the peeling film of the peeling sheet is overlapped sequentially on the exposed adhesive surface, and Laminate multiple adhesive sheets so that the total thickness falls within the range of 5mm to 7mm. This can reduce the impact of the hardness of the mounting table on which the test sample is placed, and can compare and measure the unique indentation hardness of the material. Then, the exposed adhesive surface of the laminated adhesive sheet is pressed against the front terminal of the Asker C2L hardness tester with a load of 1kg at a speed of 3mm/min vertically downward, and the C2 Asker hardness (c) of the soft part is measured.

For the adhesive sheets 2-1 to 2-7 produced in Examples and Comparative Examples, the parts that are in contact with the light-transmitting parts, that is, the hard parts, are also in the same manner as above, so that they fall within the range of 5 mm to 7 mm. For laminated adhesive sheets, measure the C2 Ascal hardness (d) of the hard part.

For the adhesive sheet 2-8 produced in Comparative Example 2-3, the same measurement was performed on an arbitrary part.

(180°peel force of the soft part)

After cutting out the parts of the adhesive sheets 2-1~2-7 that are in contact with the opaque part, that is, the soft part, of the adhesive sheets 2-1~2-7 produced in the examples and comparative examples, peel off one of the release films and stick them together as the base film A 50 μm PET film (Mitsubishi Plastics Co., Ltd., DIAFOIL T100, thickness 50 μm) was prepared as a laminate.

After cutting the above-mentioned laminated product to a length of 150mm and a width of 10mm, peel off the remaining release film, and use a 2kg roller to reciprocate the exposed adhesive surface to press-bond the above-mentioned adhesive sheet to the sodium calcium on the glass.

Measure the peeling force (N/cm) of the adhesion test sample to glass when it is peeled off at a peeling angle of 180° and a peeling speed of 60mm/min in an environment of 23°C and 40%RH. The joint part, that is, the 180° peel force of the soft part.

(180°peel force of hard part)

Peel off one of the release films from the adhesive sheets X1 to 7 produced in Examples 2-2-1 to 4 and Comparative Examples 2-1 and 2-2 before light irradiation, and attach a 50 μm substrate film A PET film (manufactured by Mitsubishi Plastics Corporation, DIAFOIL T100, 50 μm) was prepared as a laminate.

After cutting the above-mentioned laminated product to a length of 150 mm and a width of 10 mm, the remaining release film was peeled off, and the exposed adhesive surface was reciprocated with a 2 kg roller, and the roller was crimped on the soda-lime glass. After performing autoclave treatment (80°C, gauge pressure 0.2MPa, 20 minutes) on the laminated product for final bonding, irradiate ultraviolet light so that the cumulative light intensity at 365nm becomes 2000mJ/ ^cm2 to harden the adhesive sheet, and cure it for 15 hours. Prepare a peel force measurement sample.

Measure the peeling force (N/cm) to glass when the above-mentioned peeling force measurement sample is peeled at 23°C and 40%RH at a peeling angle of 180° and a peeling speed of 60mm/min, as the contact with the light-transmitting part The part, that is, the 180° peeling force of the hard part.

With respect to the adhesive sheet 2-8 produced in the comparative example 2-3, after cutting out the adhesive sheet to an arbitrary part, it measured in the same order as the 180 degreeC peeling force of a soft part.

(Retention force of soft part)

Cut the parts of the adhesive sheets 2-1 to 2-7 that are in contact with the opaque part, that is, the soft part, into 50mm x 100mm of the adhesive sheets 2-1~2-7 produced in the examples and comparative examples, and then peel off the release film on one side to use the adhesive One side of the sheet is superimposed on the polyethylene terephthalate film (thickness 38μm) for the substrate, and it is pasted with a manual roller, and it is cut into a short strip with a width of 25mm x a length of 100mm, which is used as a test piece .

Next, peel off the remaining release film, and stick it with a manual roller in such a way that the length of the test piece overlaps only 20 mm to the vertically erected SUS board (thickness 120 mm, 5 mm x 1.5 mm). At this time, the sticking area of the transparent double-sided adhesive sheet and the SUS board was 25 mm x 20 mm.

After that, the test piece was aged at 40°C and 70°C for 15 minutes, and the test piece was hung with a weight of 4.9N in the vertical direction and left to stand for 30 minutes, and the sticking position between SUS and the test piece was measured downward. Offset length (mm). For those whose sticking surface deviates and the weight falls, measure the time required for the weight to fall.

Furthermore, the adhesive sheet 2-7 of Comparative Example 2-2 does not have self-adhesiveness, so the test piece laminated on the SUS board was preheated at 80°C for 5 minutes, and the holding force was measured after it was in close contact with the adherend .

(Retention force of hard part)

Adhesive sheets X1 to 7 in the state before light irradiation produced in Examples 2-2-1 to 5 and Comparative Examples 2-1 and 2-2 were prepared in the same manner as the retention force measurement before photohardening. After the laminated body of SUS and the test piece, ultraviolet light with a wavelength of 365nm reaches the adhesive sheet at 2000mJ/cm ² , and the cumulative accumulation is confirmed by a light meter (manufactured by Ushio Electric Co., Ltd., UNIMETER UIT250/sensor: UVD-C365) For the amount of light, ultraviolet rays are irradiated from the side of the polyethylene terephthalate film for the substrate using a high-pressure mercury lamp, and an adhesive sheet corresponding to the part that is in contact with the light-transmitting part, that is, the hard part, is produced.

After that, the test piece was aged at 40°C and 70°C for 15 minutes, and the test piece was hung with a weight of 4.9N in the vertical direction and left to stand for 30 minutes, and the sticking position between SUS and the test piece was measured downward. Offset length (mm).

The test pieces were hardly moved, and those whose deviation length was less than 0.1mm were recorded as "<0.1mm" in Table 3.

For the adhesive sheet 2-8 produced in Comparative Example 2-3, after cutting out the adhesive sheet for any part, The measurement was performed in the same manner as the procedure for measuring the retention force of the soft part.

(transparency)

For the parts of the adhesive sheets 2-1~2-7 produced in Examples and Comparative Examples that are in contact with the light-transmitting part, that is, the hard part, peel off one of the release films, and roll the exposed adhesive surface to the 2 Soda-lime glass (82mm×53mm×0.5mm thick) was laid on, and then autoclaved (80°C, gauge pressure 0.2MPa, 20 minutes) for final bonding to produce a laminate for optical evaluation.

With respect to the adhesive sheet 2-8 produced in the comparative example 2-3, the sample was produced in the same manner for an arbitrary part.

About the said laminated body, the haze value based on JIS K7136 and the total light transmittance (%) based on JIS K7361-1 were calculated|required using the haze meter (Nippon Denshoku Kogyo Co., Ltd. make, NDH5000).

(concave-convex absorptivity)

Cut the adhesive sheets X1~4, 6, and 7 prepared in Examples 2-1~2-4 and Comparative Examples 2-1, 2-2 before light irradiation to 50mm×80mm, and peel off one of them for demoulding For the film, use a vacuum press to press-bond the exposed adhesive surface so that the four sides of the adhesive material cover the printing step (absolute pressure 5kPa, temperature 80°C, pressurized pressure 0.04MPa) on the peripheral part 3mm Printing surface of printed soda-lime glass (82mm×53mm×0.5mm thick) with a thickness of 80 μm. Then the remaining release film was peeled off, and the ZEONOR film (manufactured by ZEON Japan, 100 μm thick) was pressure-bonded, followed by autoclave treatment (80°C, gauge pressure 0.2MPa, 20 minutes) for final bonding. From the side of the printed soda lime glass, ultraviolet rays with a wavelength of 365nm reach the sheet X at a rate of 2000mJ/cm ² and irradiate ultraviolet rays with a high-pressure mercury lamp, so that the openings that are not printed, that is, the parts that are in contact with the light-transmitting parts The sheets were hardened to prepare laminates 2-1 to 2-6 for evaluation.

With respect to the adhesive sheet X5 produced in Example 2-5, the printed thickness of the soda-lime glass used for printing was 15 micrometers, and the laminated body 2-7 for evaluation was produced in the same manner.

For the adhesive sheet 2-8 produced in Comparative Example 2-3, use the adhesive sheet 2-7 to produce printed soda lime glass and ZEONOR film (manufactured by ZEON Japan, 100 μm thick) in the same order as above. After forming the laminate, autoclave treatment (80°C, gauge pressure 0.2MPa, 20 minutes) was carried out for final sticking, which was used as laminate 2-8 for evaluation.

Visually observe the produced laminates 2-1 to 2-8, judge as "×" if the adhesive material does not follow the adhesive material near the printing step and leave bubbles, and the film is bent near the step difference, and unevenness caused by strain can be seen Those who were judged as "△" were judged as "△", and those who adhered smoothly without air bubbles were judged as "◯".

(reliability against foaming)

Put the evaluation laminates 2-1 to 2-8 produced in the uneven absorbency evaluation into a constant temperature and humidity chamber at 85°C and 85%RH, and observe the appearance after aging for 100 hours. The case where air bubbles were generated in the adhesive sheet was judged as "x", and the case without appearance change was judged as "◯".

(investigation)

The gel fraction of the soft portion of the adhesive sheets produced in Examples 2-1 to 2-5 did not reach 1%, so they can exhibit higher fluidity by heating. Therefore, by heating and melting it at the time of lamination, not only is the followability to the uneven surface excellent, but also even if one of the adherends is a material with low rigidity such as a film, there is no bending near the step difference, and it can be obtained. Smooth laminate. Furthermore, the gel fraction of the hard part is more than 40%, so even under severe environmental tests such as high temperature and high humidity, it can exhibit high cohesion, without peeling, foaming, and deformation, and can obtain a more High reliability laminated body.

As the adhesive sheet of Comparative Example 2-1, part of the adhesive resin composition was cross-linked by ultraviolet irradiation, so when the glass and the film with printed steps were laminated, the unevenness caused by the printed steps was transferred to the film side Therefore, a smooth laminate cannot be obtained. In addition, due to the strain of the adhesive material near the step difference, foaming can be seen under the high temperature and high humidity test, and the storage stability is poor.

Comparative Example 2-2 is a hot-melt adhesive sheet using an adhesive resin composition with a certain degree of rigidity at room temperature without using a (meth)acrylic copolymer.

The sheet of Comparative Example 2-2 had very low viscosity around room temperature compared to the adhesive sheet of the examples. When laminating glass and sheets with printing steps, the fluidity during heating is low, so a little unevenness caused by printing steps is transferred on the side of the sheet. Compared with the adhesive sheet of the embodiment, the result is a laminate. The smoothness is poor. In addition, the Ascar hardness of the opaque part is relatively high, so it can be seen that the rigidity of the sheet is relatively high during lamination, and it does not have self-adhesiveness. Therefore, it is necessary to preheat the adherend at the stage of self-positioning during lamination. , Compared with adhesive sheets that can be attached at room temperature only by crimping, there is also a problem of complicated work.

In comparative example 2-3, the cross-linking reaction of the adhesive resin composition of adhesive sheet 2-7 has been completed, so there is no soft part with a gel fraction of 1% or less in the adhesive sheet, which is transferred to the film side There are irregularities caused by printing steps, so that a smooth laminate cannot be obtained. Not only that, part of the adhesive is not completely filled near the corners where the printing steps intersect, and as a result, air bubbles remain.

From the results of the above examples and the test results carried out by the inventors so far, it can be considered that if the soft part with a gel fraction of less than 1% and the hard part with a gel fraction of 40% or more are used and contain (a The base) a photocurable transparent double-sided adhesive sheet of an acrylic copolymer can allow two image display device components to be preferably bonded in the same manner as in the examples.

In addition, it is considered that the gel fraction of the soft portion within the surface of the adhesive sheet is preferably less than 1%, and the gel fraction of the hard portion is preferably 40% or more.

In addition, it can be considered that the glass transition temperature (actually measured Tg) of the soft part in the surface of the adhesive sheet is preferably -70~-10°C, the glass transition temperature (actually measured Tg) of the hard part is -60~+20°C, and the hard part The difference (Tg[H]-Tg[S]) between the glass transition temperature (Tg[H]) of the soft part and the glass transition temperature (Tg[S]) of the soft part is preferably 3°C or more.

[Example 2-6]

For the adhesive sheet X1 made in Example 2-1, the width is 150mm, and the length is 100m. The laminated sheet of the strip is wound on a plastic core with a diameter of 6 inches with an initial winding tension of 70N and a push-pull ratio of 20%, to make an adhesive sheet roll.

Using a high-pressure mercury lamp, irradiate the end face of the produced sheet roll with a cumulative light intensity of 500mJ/ ^cm2 at a wavelength of 365nm to light-harden the end face and become an adhesive sheet roll with a hard part on the end face .

[Comparative example 2-4]

An adhesive sheet roll was produced in the same manner as in Example 2-6 except that light irradiation was not performed.

For the adhesive sheet rolls of Comparative Example 2-4 with no hard parts and only soft parts and the adhesive sheet rolls of Examples 2-6 with hard parts on the end face, they were tested at 40°C and 90% After storing in a constant temperature and humidity tank of RH for 2 weeks, visually observe the end face of the adhesive sheet roll.

As the adhesive sheet roll of Example 2-5, which has a hard part on the end part, the paste does not overflow from the end part, and the unwinding workability of the sheet is good, compared to Comparative Example 2-4 which only includes a soft part. The end face of the adhesive sheet reel overflows with paste, which causes the end face to become sticky, resulting in obstacles to the unwinding operation.

[Example 3-1]

As the (meth)acrylic copolymer (3-A), 15 parts by mass (18 mol%) of polymethyl methacrylate macromonomer (Tg: 105°C, number average molecular weight 2400) and butyl acrylate ( A graft copolymer (3-A1) obtained by random copolymerization of 81 parts by mass (75mol%) of Tg: -55°C) and 4 parts by mass (7mol%) of acrylic acid (Tg: 106°C).

In this graft copolymer (3-A1), the glass transition temperature of the copolymer constituting the main component is -60°C, the content of the macromonomer in the graft copolymer (3-A1) is 15% by mass, and the temperature The complex viscosity at 130℃ and frequency 0.02Hz is 260Pa‧s.

1 kg of the graft copolymer (3-A1), 90 g of glycerol dimethacrylate (manufactured by NOF Corporation, product name: GMR) as a crosslinking agent (3-B), and 90 g of a photopolymerization initiator were uniformly mixed. (3-C) 15 g of a mixture of 2,4,6-trimethylbenzophenone and 4-methylbenzophenone (manufactured by Lanberti, product name: Esacure TZT) to prepare adhesive resin composition 3 -1.

Use the above-mentioned adhesive resin composition 3-1 as two release films, that is, two polyethylene terephthalate films ("DIAFOIL MRV-V06" manufactured by Mitsubishi Plastics Co., Ltd., thickness 100 μm / Mitsubishi Plastics Co., Ltd.) after peeling treatment Manufacture "DIAFOIL MRQ" (thickness: 75 μm) sandwiched, and shaped into a sheet using a laminating machine so as to have a thickness of 150 μm, and an adhesive sheet 3-1 (thickness: 150 μm) was produced.

[Example 3-2]

Except using 90 g of glycerin dimethacrylate (manufactured by Shin Nakamura Chemical Industry Co., Ltd., product name: NK ester 701) (3-B-1) as the crosslinking agent (3-B), the same as in Example 3-1 Adhesive resin composition 3-2 was prepared in the same way.

Using the above-mentioned adhesive resin composition 3-2, an adhesive sheet 3-2 (thickness 150 μm) was produced in the same manner as in Example 3-1.

[Example 3-3]

Uniformly mix 1 kg of the same graft copolymer (3-A1) as in Example 3-1, 90 g of glycerol dimethacrylate (manufactured by NOF Corporation, product name: GMR) as a crosslinking agent (3-B), and 15 g of a mixture of 2,4,6-trimethylbenzophenone and 4-methylbenzophenone (manufactured by Lanberti, product name: Esacure TZT) as a photopolymerization initiator (3-C), An ultraviolet stabilizer (manufactured by Ciba Japan, product name: TIN123) was 50 g, and an adhesive resin composition 3-3 was produced.

And the adhesive sheet 3-3 (150 micrometers in thickness) was produced in the same manner as Example 3-1 using this adhesive resin composition 3-3.

[Example 3-4]

As the (meth)acrylic copolymer (3-A), 10 parts by mass (12 mol%) of polymethyl methacrylate macromonomer (Tg: 105°C, number average molecular weight 2500) and butyl acrylate ( A graft copolymer (3-A2) obtained by random copolymerization of 88 parts by mass (84mol%) of Tg: -55°C) and 2 parts by mass (7mol%) of acrylic acid (Tg: 106°C).

In this graft copolymer (3-A2), the glass transition temperature of the copolymer constituting the main component is -60°C, and the content of the macromonomer in the graft copolymer (3-A2) is 10% by mass. The complex viscosity at a temperature of 130°C and a frequency of 0.02Hz is 240Pa‧s.

1 kg of the graft copolymer (3-A2), 50 g of trimethylolpropane triacrylate (manufactured by Shin-Nakamura Chemical Industry Co., Ltd., product name: CLM400) as a crosslinking agent (3-B), and 50 g of a photopolymer (3-A2) were uniformly mixed. 15 g of a mixture of 2,4,6-trimethylbenzophenone and 4-methylbenzophenone (manufactured by Lanberti, product name: Esacure TZT) as a polymerization initiator (3-C) to make an adhesive Resin composition 3-4.

And, the adhesive sheet 3-4 (150 micrometers in thickness) was produced in the same manner as Example 3-1 using this adhesive resin composition 3-4.

[Example 3-5]

As (meth)acrylic copolymer (3-A), 8 mass parts (10mol%) of polymethyl methacrylate macromonomer (Tg: 105°C, number average molecular weight of 2500) and butyl acrylate ( A graft copolymer (3-A3) obtained by random copolymerization of 89 parts by mass (85mol%) of Tg: -55°C) and 3 parts by mass (5mol%) of acrylic acid (Tg: 106°C).

In this graft copolymer (3-A3), the glass transition temperature of the copolymer constituting the main component is -40°C, and the content of the macromonomer in the graft copolymer (3-A3) is 8% by mass. The complex viscosity at a temperature of 130°C and a frequency of 0.02Hz is 220Pa‧s.

Uniformly mix 1kg of the graft copolymer (3-A3), glycerol dimethyl as crosslinking agent (3-B) 90 g of acrylate (manufactured by NOF Corporation, product name: GMR), and 2,4,6-trimethylbenzophenone and 4-methylbenzophenone as photopolymerization initiators (3-C) 15 g of the mixture (manufactured by Lanberti, product name: Esacure TZT) was used to prepare adhesive resin compositions 3-5.

And using this adhesive resin composition 3-5, the adhesive sheet 3-5 (thickness 150 micrometers) was produced in the same manner as Example 3-1.

[Comparative Example 3-1]

Produced in a manner equivalent to the embodiment of International Publication No. 2012/032995.

That is, in the (meth)acrylic copolymer (3-A), 75 parts by mass (57 mol%) of 2-ethylhexyl acrylate (Tg: -70°C) and vinyl acetate (Tg: 32°C) 20 parts by mass (33mol%) and 5 parts by mass (10mol%) of acrylic acid (Tg: 106°C) were randomly copolymerized into 1 kg of acrylic copolymer (3-A-5), mixed and added as a crosslinking agent ( 3-B) 200g of trimethylolpropane triacrylate (3-B-4) and 10g of 4-methylbenzophenone (3-C-3) as photopolymerization initiator (3-C) A resin composition for an intermediate layer was prepared.

The resin composition for the intermediate layer was sandwiched between two peeled polyethylene terephthalate films (manufactured by Panac, NP75Z01, thickness 75 μm/manufactured by Toyobo Co., Ltd., E7006, thickness 38 μm), with a thickness of Shaped into a sheet with a thickness of 80 μm, the intermediate layer sheet (α) was produced.

Next, add and mix 20 g of 4-methylbenzophenone (3-C-3) as a photopolymerization initiator (3-C) to 1 kg of the above-mentioned acrylic copolymer (3-A-5) to prepare an adhesive layer Use a resin composition.

The resin composition for the adhesive layer is used as two release films, that is, two polyethylene terephthalate films ("DIAFOIL MRA" manufactured by Mitsubishi Plastics Co., Ltd., thickness 75 μm/"E7006" manufactured by Toyobo Co., Ltd.) , thickness 38 μm) sandwiched, and formed into a sheet shape so that the thickness becomes 35 μm, and the resin sheet (β) for an adhesive layer was produced.

Furthermore, the resin composition for the adhesive layer was sandwiched between two peeled polyethylene terephthalate films (manufactured by Mitsubishi Plastics Corporation, DIAFOIL MRF, thickness 75 μm/manufactured by Toyobo Co., Ltd., E7006, thickness 38 μm), and It shaped into a sheet shape so that thickness might become 35 micrometers, and produced the resin sheet (β') for adhesive layers.

Sequentially peel and remove the PET film on both sides of the middle layer sheet (α), and peel off the PET film on one side of the adhesive layer resin sheet (β) and (β'), and stick the exposed adhesive surface in sequence A 3-layer adhesive sheet consisting of (β)/(α)/(β') was prepared by attaching to both surfaces of the sheet (α) for the intermediate layer.

The remaining PET film on the surface of (β) and (β') is irradiated with ultraviolet rays by a high-pressure mercury lamp in such a way that the cumulative light intensity at a wavelength of 365nm becomes 1000mJ/ ^cm2 , so that (α), (β) and (β') Ultraviolet crosslinking was carried out to produce an adhesive sheet 3-6 (thickness 150 μm).

[Comparative Example 3-2]

The adhesive sheet was produced according to Example 6 of WO2010/038366.

That is, 650 g of a phenoxy resin (manufactured by InChem, PKHH, weight average molecular weight: 52,000) as a substitute for the (meth)acrylic copolymer (3-A) and 650 g as a substitute for the crosslinking agent (3-B) were uniformly mixed. 1 kg of polyacrylic urethane (manufactured by Negami Industrial Co., Ltd., UN5500, weight average molecular weight 67,000) with a carbonate skeleton, and 1-cyclohexyl phenyl ketone (3-C) as a photopolymerization initiator (3-C) Made by BASF Corporation, Irgacure 184) 43 g, and adhesive resin composition 3-7 was prepared.

The above-mentioned composition 3-7 was prepared in the same manner as in Example 3-1 to produce an adhesive sheet 3-7 (thickness: 150 μm).

[evaluate]

The adhesive sheets and laminates produced in Examples and Comparative Examples were evaluated as follows.

(tensile elastic modulus, breaking strength, breaking elongation)

Adhesive sheets 3-1~3-7 were cut to a width of 20mm, and used as samples for tensile test before photocrosslinking.

After cutting the adhesive sheets 3-1 to 3-7 to a width of 20mm, use a high-pressure mercury lamp to irradiate ultraviolet light from the demoulding PET side to harden the adhesive sheet in such a way that the cumulative light intensity at 365nm becomes 2000mJ/cm ² , at 23°C , Cured for 15 hours at 50% RH, used as a sample for tensile test after photocrosslinking.

For the above tensile test, the tensile modulus, tensile breaking strength and tensile breaking elongation of the sample were measured under the environment of 23°C and 50%RH at a test speed of 300mm/min.

Furthermore, in the measurement conditions of the tensile elastic modulus, the displacement is 30 to 50 mm.

(gel fraction)

Take out the parts of the adhesive sheets 3-1 to 3-7 that are in contact with the light-transmitting part, that is, the hard part, and the part that is in contact with the opaque part, that is, the soft part, of the adhesive sheets 3-1~3-7 produced in the examples and comparative examples, respectively. Those who took out were subjected to the following measurements.

1) Weigh the adhesive resin composition (W1), and wrap it in a 200-mesh SUS screen (W0) with a predetermined weight.

2) Immerse the above SUS mesh in 100 mL of ethyl acetate for 24 hours.

3) Take out the SUS screen and semi-dry at 75°C for 4 hours.

4) The weight (W2) after drying is obtained, and the gel fraction of the adhesive composition is determined by the following formula.

Gel fraction (%)=100×(W2-W0)/W1

(operability (storage))

Clamp the adhesive sheets 3-1~3-7 cut into 50mm×50mm square in 100 A laminate is made between two glass plates with a square of mm×100mm and a thickness of 2mm. Place a 500g weight on the laminate, and place it at 60°C for 24 hours, then visually observe whether the adhesive overflows from the laminate.

The produced laminate was visually observed, and the case where the adhesive overflowed as a whole was judged as "×", the case where the adhesive overflowed only from the corner was judged as "△", and the case where the adhesive did not overflow was judged as "○".

(step absorbency)

Cut the adhesive sheets 3-1~3-6 produced in Examples 3-1~3-5 and Comparative Example 3-1 into 50mm×80mm before light irradiation, peel off one of the release films, and use a vacuum The press machine presses and presses the exposed adhesive surface with the four sides of the adhesive covering the printing step (absolute pressure 5kPa, temperature 80°C, pressurized pressure 0.04MPa) and prints with a thickness of 80μm on the peripheral part of 3mm The printing surface of soda lime glass (82mm×53mm×0.5mm thick). Then the remaining release film was peeled off, and the ZEONOR film (manufactured by ZEON Japan, 100 μm thick) was pressure-bonded, followed by autoclave treatment (80°C, gauge pressure 0.2MPa, 20 minutes) for final bonding.

Next, from the side of the printed soda lime glass, irradiate ultraviolet light with a wavelength of 365nm at 2000mJ/ ^cm2 to the sheet X by means of a high-pressure mercury lamp, so that the opening without printing is in contact with the transparent part The sheets at the parts were hardened to make laminates 3-1 to 3-6 for evaluation.

For the adhesive sheet 3-7 produced in Comparative Example 3-2, use the adhesive sheet 3-7 to produce printed soda lime glass and ZEONOR film (manufactured by ZEON Japan, 100 μm thick) in the same order as above. After the laminated body was formed, autoclave treatment (80°C, gauge pressure 0.2 MPa, 20 minutes) was carried out for final sticking, which was used as laminated body 3-7 for evaluation.

Visually observe the produced laminates 3-1~3-7, judge as "×" if the adhesive material does not follow the adhesive material near the printing step and leave bubbles, and the film is bent near the step difference, and unevenness caused by strain can be seen Those who were judged as "△" and those who fit smoothly without air bubbles were judged as "○".

The adhesive sheets produced in Examples 3-1 to 3-5 are those with large changes in tensile properties before and after photohardening. Because of this characteristic, it was confirmed that the adhesive sheets produced in Examples 3-1 to 3-5 have excellent step absorption before photocuring, and on the other hand have excellent foaming resistance after photocuring sex.

On the other hand, in Comparative Example, the change in tensile properties before and after photocuring was not sufficient, so the change after photocrosslinking in Comparative Example 3-1 was not sufficient, so it became a sheet with poor reliability. Comparative Example 3 In -2, the workability (storability) before photocrosslinking was poor.

Claims (9)

An adhesive sheet, which is characterized in that it contains a (meth)acrylic copolymer (A) and is light-cured, and has a gel fraction of less than 1% of the sheet part and a gel fraction The glass transition temperature (Tg[S]) measured by a differential scanning calorimeter (DSC) for the sheet part with a gel fraction of less than 1% is -70~-10 The glass transition temperature (Tg[H]) of the sheet part with a gel fraction of 40% or more measured by a differential scanning calorimeter (DSC) is -60~+20°C, and the gel fraction is The difference (Tg[H]-Tg[S]) between the glass transition temperature of the sheet portion of 40% or more and the glass transition temperature of the sheet portion of less than 1% gel fraction is 3°C or more. The adhesive sheet according to claim 1, which is a part of a sheet formed from a resin composition containing a (meth)acrylic copolymer (A), a crosslinking agent (B) and a photopolymerization initiator (C) Light hardened. The adhesive sheet according to claim 1 or 2, wherein the (meth)acrylic copolymer (A) is a graft copolymer having a macromonomer as a branch component. The adhesive sheet according to claim 1 or 2, wherein the above-mentioned (meth)acrylic copolymer (A) is a monomer a1 whose glass transition temperature (Tg) does not reach 0°C, and the glass transition temperature (Tg) is 0°C Monomer a2 above and below 80°C and monomer a3 with a glass transition temperature (Tg) above 80°C are combined at a molar ratio of a1:a2:a3=10~40:90~35:0~25 Polymerized, and the weight average molecule The amount is 50000~400000 (meth)acrylic copolymer. The adhesive sheet according to claim 1 or 2, wherein the adhesive sheet has a sheet portion with a gel fraction of less than 1% and a sheet portion with a gel fraction of 40% or more within the sheet surface of the adhesive sheet. An adhesive sheet laminate, which is formed by laminating the adhesive sheet according to any one of Claims 1 to 5 and a release film. A laminate for constituting an image display device, comprising a structure in which two constituting members for an image display device are laminated with the adhesive sheet according to any one of Claims 1 to 5 interposed therebetween. The laminated body for forming an image display device according to Claim 7, wherein the constituent member of the image display device is any one selected from the group consisting of a touch panel, an image display panel, a surface protection panel, and a polarizing film or includes A laminate of two or more combinations. An image display device constructed using the laminate for image display device construction according to claim 7 or 8.

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