KR20210112348A - adhesive sheet - Google Patents

Abstract

To provide a novel pressure-sensitive adhesive sheet capable of exhibiting good reworkability in the initial stage of affixing to an adherend and capable of greatly increasing the adhesive strength within a short time by a mild heating at about 50°C after that. A pressure-sensitive adhesive sheet including a pressure-sensitive adhesive layer is provided. The pressure-sensitive adhesive layer includes a polymer A and a polymer B, which is a copolymer of a monomer having a polyorganosiloxane skeleton and a (meth)acrylic monomer. This pressure-sensitive adhesive sheet exhibits an _{adhesive force N 50 of 5 N/25 mm or more.} Here, the adhesive force N ₅₀ refers to the adhesive force measured at 23° C. after bonding to a stainless steel sheet and maintaining at 50° C. for 15 minutes.

Description

adhesive sheet

The present invention relates to an adhesive sheet.

This application claims the priority based on Japanese Patent Application No. 2019-001349 for which it applied on January 8, 2019, The whole content of the application is incorporated by reference in this specification.

The pressure-sensitive adhesive sheet is strongly adhered to an adherend, and thus is used for the purposes of adhesion of adherends to each other, fixing of articles to adherends, reinforcement of adherends, and the like. Conventionally, the adhesive sheet which exhibits high adhesive force from the initial stage of sticking has been used for this purpose. Moreover, like patent documents 1 - 3, the adhesive sheet which shows low adhesive force at the initial stage of pasting to a to-be-adhered body, and can raise adhesive force largely after that is proposed. According to the pressure-sensitive adhesive sheet having such properties, before the adhesive strength rises, reattachability (reworkability) useful for suppression of a decrease in yield due to an adhesion error or adhesion damage of the pressure-sensitive adhesive sheet is exhibited. It can exhibit strong adhesion suitable for the purpose of use.

Japanese Patent Application Laid-Open No. 2014-224227 Japanese Patent Publication No. 5890596 Japanese Patent No. 5951153

The pressure-sensitive adhesive sheet described in the prior art document shows low adhesive strength at the initial stage of attachment, and by exposing it to a high temperature around 80 ° C. . Thereby, the raise of adhesive force is controlled reliably. By the way, usage in the manufacturing process of a product etc. are included in the usage aspect of this kind of adhesive sheet, In such a use, a simpler process from a viewpoint of efficiency (production efficiency) improvement in a manufacturing process is included. It may be advantageous to increase the adhesive force with For example, if an adhesive sheet capable of increasing adhesive strength in a short time by heating closer to room temperature (mild heating) is provided, the adhesive strength increasing treatment can be efficiently and reliably performed without unevenness, thereby improving production efficiency. can be advantageous in that respect. Since the pressure-sensitive adhesive sheet having such properties can be applied to an adherend that is undesirable to be exposed to a high temperature state, a new application development can also be expected. Therefore, the present invention provides a novel pressure-sensitive adhesive sheet capable of exhibiting good reworkability in the initial stage of affixing to an adherend, and after that, the adhesive force can be greatly increased in a short time by mild heating at about 50° C. aim to do

According to the present specification, an adhesive sheet including an adhesive layer is provided. The pressure-sensitive adhesive layer includes a polymer A and a polymer B, which is a copolymer of a monomer having a polyorganosiloxane skeleton and a (meth)acrylic monomer. This pressure-sensitive adhesive sheet exhibits an _{adhesive force N 50 of 5 N/25 mm or more.} Here, the adhesive force N ₅₀ refers to the adhesive force measured at 23° C. after bonding to a stainless steel sheet and maintaining at 50° C. for 15 minutes.

The adhesive sheet of the said structure can show favorable rework property based on the action|action of the polymer B which has a polyorganosiloxane skeleton in the initial stage of pasting. Thereafter, the adhesive force can be raised to a predetermined value or more by mild heating at about 50°C.

The adhesive sheet which concerns on some preferable aspect is 3N/25mm or less of _{adhesive force N 23} measured after bonding to a stainless steel plate and hold|maintaining at 23 degreeC for 30 minutes. The adhesive sheet which satisfies this characteristic shows favorable rework property, since adhesive force is suppressed low in the initial stage of pasting. That is, the increase in adhesive force after initial stage light peeling property (rework property) and mild heating can be compatible preferably.

In the pressure-sensitive adhesive sheet according to some preferred embodiments, the adhesive force N ₅₀ is 5 times or more of _{the adhesive force N 23} measured after bonding to a stainless steel sheet and maintaining at 23° C. for 30 minutes. _{Thus, according to the pressure-sensitive adhesive sheet in which the adhesive force N 50} is 5 times or more (N ₅₀ /N ₂₃ ≥ 5) with respect to the adhesive force N ₂₃ , good rework property is shown at the initial stage of pasting, and the adhesive force is greatly increased by subsequent heating or the like. can elevate

_{The pressure-sensitive adhesive sheet according to some embodiments has an adhesive force N 80} measured at 23° C. after bonding to a stainless steel sheet and maintaining at 80° C. for 5 minutes, twice or less of the adhesive force N _{50 (ie, N 80} /N ₅₀ ≤ 2) can be A pressure-sensitive adhesive sheet that satisfies this characteristic sufficiently increases its adhesive strength by mild heating at about 50° C., so it is not necessary to expose it to a further high temperature (specifically, heating at about 80° C.) in order to obtain strong adhesive strength. According to the adhesive sheet which satisfy|fills this characteristic, adhesive force can be raised to a desired level more efficiently than before.

Moreover, it is preferable that the storage elastic modulus G' (150 degreeC) of the said adhesive layer at 150 degreeC is 10,000 Pa or more and 90,000 Pa or less. The pressure-sensitive adhesive layer that satisfies the above 150°C storage modulus tends to exhibit good adhesive properties, and polymer B tends to move in the pressure-sensitive adhesive layer, so based on its mobility, it is possible to preferably achieve an increase in adhesive strength after mild heating. .

In the technique disclosed herein, the polymer A contained in the pressure-sensitive adhesive layer is typically chemically crosslinked. Thereby, the adhesive sheet can exhibit favorable adhesive properties. In addition, in a configuration in which the degree of crosslinking is limited so that the storage modulus G' (150° C.) is equal to or less than a predetermined value, based on the mobility of the polymer B in the pressure-sensitive adhesive layer, an increase in adhesive strength after mild heating can be preferably realized. have. In some embodiments, the pressure-sensitive adhesive layer may include more than 0 parts by weight and not more than 10 parts by weight of the crosslinking agent based on 100 parts by weight of the polymer A. By using the crosslinking agent, chemical crosslinking that satisfies the desired properties is preferably realized, and a storage elastic modulus G' (150° C.) in a predetermined range can be preferably realized.

In some embodiments, the weight average molecular weight of Polymer B may be 100,000 or more. Also in the aspect in which the polymer B having Mw of a predetermined or higher is used, the effect by the technique disclosed herein can be preferably realized.

In some preferred forms, the weight average molecular weight of Polymer B may be less than 80,000. By using the polymer B whose Mw is less than a predetermined value, the adhesive force increase after mild heating can be implement|achieved preferably.

In some aspects, content of the said polymer B in the said adhesive layer can be made into the range of 0.5 weight part or more and 50 weight part or less with respect to 100 weight part of said polymer A. According to content in the said range, the adhesive force raise after a mild heating can be implement|achieved preferably.

The polymer A is preferably an acrylic polymer. According to the adhesive layer containing the polymer A which is an acryl-type polymer, and the polymer B which is a copolymer of the monomer which has a polyorganosiloxane backbone, and a (meth)acrylic-type monomer, the adhesive force increase after mild heating can be implement|achieved preferably.

In some embodiments, the acrylic polymer preferably includes a monomer having a nitrogen atom-containing ring as a monomer unit thereof. Polymer A containing a monomer unit having a nitrogen atom-containing ring is used in combination with polymer B, whereby an increase in adhesive strength after mild heating can be preferably realized.

In some preferred embodiments, the monomer component for preparing the polymer B contains, as the (meth)acrylic monomer (monomer M2), a monomer having a glass transition temperature of 50° C. or higher of a homopolymer in a proportion of 60% by weight or less. . In the polymer B, since the copolymerization ratio of the monomer M2 of Tg50°C or higher is limited to a predetermined value or less, an increase in adhesive strength after mild heating can be preferably realized based on the mobility of the polymer B in the vicinity of 50°C. As said monomer M2, the Tg of a homopolymer can use 50 degreeC or more preferably (meth)acrylic acid alkylester (namely, alkyl (meth)acrylate).

The pressure-sensitive adhesive sheet disclosed herein includes a support substrate having a first surface and a second surface, and the pressure-sensitive adhesive layer is laminated on at least the first surface of the support substrate, that is, in the form of a pressure-sensitive adhesive sheet provided with a substrate. can be carried out. Such an adhesive sheet with a base material can become a thing with good handleability and processability. As said support base material, the resin film 30 micrometers or more in thickness can employ|adopt preferably, for example.

Moreover, according to this specification, the adhesive sheet containing an adhesive layer is provided. The pressure-sensitive adhesive layer includes a polymer A and a polymer B, which is a copolymer of a monomer having a polyorganosiloxane skeleton and a (meth)acrylic monomer. And, the storage elastic modulus G' (150° C.) of the pressure-sensitive adhesive layer at 150° C. is 10,000 Pa or more and 90,000 Pa or less. According to the adhesive sheet provided with the adhesive layer which satisfies the said 150 degreeC storage elastic modulus, based on the action|action of polymer B, while it is possible to show favorable rework property, thereafter, the adhesive strength by mild heating of about 50 degreeC can elevate

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows typically the structure of the adhesive sheet which concerns on one Embodiment.
It is sectional drawing which shows typically the structure of the adhesive sheet which concerns on another one Embodiment.
It is sectional drawing which shows typically the structure of the adhesive sheet which concerns on another one Embodiment.

Hereinafter, preferred embodiments of the present invention will be described. Matters other than those specifically mentioned in this specification and necessary for the implementation of the present invention can be understood by those skilled in the art based on the teachings for the implementation of the invention described in this specification and the technical common sense at the time of filing. The present invention can be implemented based on the content disclosed in this specification and common technical knowledge in the field.

In addition, in the following drawings, the same code|symbol may be attached|subjected to the member and site|part exhibiting the same effect|action, and description may be given, and overlapping description may be abbreviate|omitted or simplified. In addition, embodiment described in the drawing is schematically illustrated in order to demonstrate this invention clearly, and does not necessarily show exactly the size and scale of the actually provided product.

In addition, in this specification, "acrylic polymer" refers to a polymer containing a monomer unit derived from a (meth)acrylic monomer in a polymer structure, and typically 50% by weight of a monomer unit derived from a (meth)acrylic monomer. It refers to a polymer containing in an excess ratio. In addition, a (meth)acrylic-type monomer means the monomer which has at least 1 (meth)acryloyl group in 1 molecule. Here, "(meth)acryloyl group" is the meaning which points out an acryloyl group and a methacryloyl group comprehensively. Accordingly, the concept of the (meth)acrylic monomer referred to herein may include both a monomer having an acryloyl group (acrylic monomer) and a monomer having a methacryloyl group (methacrylic monomer). Similarly, in this specification, "(meth)acrylic acid" refers to acrylic acid and methacrylic acid, and "(meth)acrylate" refers to acrylate and methacrylate inclusively, respectively.

<Structural example of adhesive sheet>

The adhesive sheet disclosed here is comprised including the adhesive layer. The PSA sheet disclosed herein may be in the form of an PSA sheet provided with a base material in which the PSA layer is laminated on one or both surfaces of a supporting base material, or may be in the form of a base material-free PSA sheet having no supporting base material. Hereinafter, the supporting base material may be simply referred to as a "base material".

The structure of the adhesive sheet which concerns on one Embodiment is schematically shown in FIG. This pressure-sensitive adhesive sheet 1 includes a sheet-shaped support substrate 10 having a first surface 10A and a second surface 10B, and an pressure-sensitive adhesive layer 21 formed on the first surface 10A side. It is comprised as a single-sided adhesive sheet provided with the base material which says. The pressure-sensitive adhesive layer 21 is adhered to the side of the first surface 10A of the supporting substrate 10 . The adhesive sheet 1 is used by affixing the adhesive layer 21 to a to-be-adhered body. As shown in FIG. 1, the adhesive sheet 1 before use (that is, before sticking to a to-be-adhered body) 21 A of surfaces (adhesive surface) of the adhesive layer 21 is at least adhesive layer 21. It may be a component of the pressure-sensitive adhesive sheet 100 provided with a release liner in a form in which the side opposite to the release liner 31 is in contact with the release liner 31 having a release surface (release surface). As the release liner 31, for example, by forming a release layer with a release treatment agent on one surface of a sheet-shaped base material (liner base material), one configured so that the single surface becomes a release surface can be preferably used. Alternatively, the release liner 31 is omitted and the pressure-sensitive adhesive surface 21A is formed on the support substrate 10 by winding the pressure-sensitive adhesive sheet 1 using the support substrate 10 having the second surface 10B serving as the release surface. ) may be in a form (roll form) in contact with the second surface 10B. When the adhesive sheet 1 is affixed to an adherend, the release liner 31 or the second surface 10B of the supporting substrate 10 is peeled off from the adhesive surface 21A, and the exposed adhesive surface 21A is removed. Compress to the complex.

The structure of the adhesive sheet which concerns on another one Embodiment is schematically shown in FIG. The pressure-sensitive adhesive sheet 2 includes a sheet-shaped support substrate 10 having a first surface 10A and a second surface 10B, and a pressure-sensitive adhesive layer 21 formed on the first surface 10A side thereof; It is comprised as a double-sided adhesive sheet with a base material provided with the adhesive layer 22 provided in the 2nd surface 10B side. The pressure-sensitive adhesive layer (first pressure-sensitive adhesive layer) 21 is on the first surface 10A of the support substrate 10 , and the pressure-sensitive adhesive layer (second pressure-sensitive adhesive layer) 22 is on the second surface 10B of the support substrate 10 . , respectively, are fixed. The pressure-sensitive adhesive sheet 2 is used by affixing the pressure-sensitive adhesive layers 21 and 22 to different locations of the adherend. Each location of a different member may be sufficient as the location to which the adhesive layers 21 and 22 are affixed, and the different location in a single member may be sufficient as it. As shown in FIG. 2, the adhesive sheet 2 before use is 21 A of surfaces (1st adhesive side) of the adhesive layer 21, and 22 A of surfaces (2nd adhesive side) of the adhesive layer 22. This may be a component of the pressure-sensitive adhesive sheet 200 provided with a release liner, in which at least the side opposite to the pressure-sensitive adhesive layers 21 and 22 is in contact with the release liners 31 and 32 serving as the release surfaces, respectively. As the release liners 31 and 32, for example, a release liner formed by forming a release layer with a release agent on one surface of a sheet-like base material (liner base material) so that the single surface becomes a release surface can be preferably used. Alternatively, by omitting the release liner 32 and using a release liner 31 having a release surface on both sides, overlapping this and the pressure-sensitive adhesive sheet 2 and winding the pressure-sensitive adhesive sheet 2 in a spiral wound shape, so that the second pressure-sensitive adhesive surface 22A is formed. You may comprise the adhesive sheet with a release liner of the form (roll form) contact|abutted to the back surface of the release liner 31.

Fig. 3 schematically shows the structure of the pressure-sensitive adhesive sheet according to still another embodiment. This pressure-sensitive adhesive sheet 3 is configured as a non-substrate double-sided pressure-sensitive adhesive sheet including the pressure-sensitive adhesive layer 21 . The pressure-sensitive adhesive sheet 3 is made of a first pressure-sensitive adhesive surface 21A formed by one surface (first surface) of the pressure-sensitive adhesive layer 21 and the other surface (second surface) of the pressure-sensitive adhesive layer 21 . It is used by affixing the 2 adhesive surfaces 21B to different locations of a to-be-adhered body. As shown in FIG. 3, the adhesive sheet 3 before use has the 1st adhesive surface 21A and the 2nd adhesive surface 21B, the side which opposes at least the adhesive layer 21 is a peeling surface, respectively, It may be a component of the pressure-sensitive adhesive sheet 300 having a release liner in contact with the release liners 31 and 32 . Alternatively, by omitting the release liner 32 and using a release liner 31 having both surfaces as a release surface, overlapping this and the pressure-sensitive adhesive sheet 3 and winding the pressure-sensitive adhesive sheet 3 in a spiral wound shape, the second adhesive surface 21B is formed. You may comprise the adhesive sheet with a release liner of the form (roll form) contact|abutted to the back surface of the release liner 31.

In addition, what is called an adhesive tape, an adhesive film, an adhesive label, etc. can be contained in the concept of the adhesive sheet here. The pressure-sensitive adhesive sheet may be in the form of a roll or in the form of a sheet, or may be one that has been cut, punched, or the like into an appropriate shape depending on the application or use mode. The pressure-sensitive adhesive layer in the technique disclosed herein is typically formed continuously, but is not limited thereto, and may be formed in a regular or random pattern such as a dot shape or a stripe shape, for example.

<Adhesive layer>

The pressure-sensitive adhesive sheet disclosed herein includes a pressure-sensitive adhesive layer comprising a polymer A and a polymer B which is a copolymer of a monomer having a polyorganosiloxane skeleton and a (meth)acrylic monomer. Such a pressure-sensitive adhesive layer may be formed of a pressure-sensitive adhesive composition containing the polymer A, which is a complete or partial polymerization product of the monomer raw material A, and the polymer B. The form of the pressure-sensitive adhesive composition is not particularly limited, and may be, for example, various forms such as a solvent type, a water dispersion type, a hot melt type, and an active energy ray curing type (eg, a photocurable type).

(Polymer A)

As polymer A, rubber elasticity in the room temperature range of known acrylic polymers, rubber polymers, polyester polymers, urethane polymers, polyether polymers, silicone polymers, polyamide polymers, fluorine polymers, etc. in the field of adhesives One type or two or more types of the various polymers shown can be used. In the pressure-sensitive adhesive sheet disclosed herein, the polymer A is typically a main component of the polymer component contained in the pressure-sensitive adhesive layer, that is, a component that occupies more than 50% by weight, for example, a component that accounts for 75% by weight or more of the polymer component can be Some aspects WHEREIN: The said polymer A is a component which occupies more than 50 weight% of the whole adhesive layer, and the component which occupies 70 weight% or more may be sufficient.

The glass transition temperature T _A of the polymer A is not particularly limited, and the desired properties in the pressure-sensitive adhesive sheet disclosed herein can be selected is obtained. In some embodiments, _{polymer A having a T A} of less than 0° C. may be preferably employed. The adhesive containing such a polymer A is suitable for realization of an adhesive sheet in which the adhesive strength rises to a predetermined value or more by mild heating in that it exhibits moderate fluidity (for example, the mobility of a polymer chain contained in the adhesive). do. The pressure-sensitive adhesive sheet _{disclosed herein can be preferably implemented using a polymer A having a T A} of less than -10°C, less than -20°C, less than -30°C, or less than -35°C. In some embodiments, T _A may be less than -40°C or less than -50°C. The lower limit of T _A is not particularly limited. From the viewpoint of easiness of material availability and improvement of the cohesive force of the pressure-sensitive adhesive layer _{, generally, polymer A having a T A} of -80°C or higher, -70°C or higher, or -65°C or higher can be preferably employed. In some embodiments, T _A may be, for example, -63°C or higher, -55°C or higher, -50°C or higher, or -45°C or higher.

Here, in this specification, the glass transition temperature (Tg) of a polymer is a nominal value described in literature or catalogs, etc. . The Fox formula is a relational expression between Tg of the copolymer and the glass transition temperature Tgi of a homopolymer obtained by homopolymerizing each of the monomers constituting the copolymer, as described below.

1/Tg=Σ(Wi/Tgi)

In the Fox formula, Tg is the glass transition temperature of the copolymer (unit: K), Wi is the weight fraction of the monomer i in the copolymer (copolymerization ratio based on weight), and Tgi is the glass of the homopolymer of the monomer i. It represents the transition temperature (unit: K). When the target polymer for the specification of Tg is a homopolymer, the Tg of the homopolymer and the Tg of the target polymer match.

As the glass transition temperature of the homopolymer used for the calculation of Tg, the value described in known materials is used. Specifically, numerical values are exemplified in "Polymer Handbook" (3rd ed., John Wiley & Sons, Inc., 1989). For monomers for which a plurality of types of values are described in the Polymer Handbook, the highest value is employed.

As the glass transition temperature of the homopolymer of the monomer not described in the Polymer Handbook, a value obtained by the following measurement method is used.

Specifically, 100 parts by weight of the monomer, 0.2 parts by weight of 2,2'-azobisisobutyronitrile, and 200 parts by weight of ethyl acetate as a polymerization solvent were introduced into a reactor equipped with a thermometer, a stirrer, a nitrogen introduction tube and a reflux cooling tube. and stirred for 1 hour while flowing nitrogen gas. After removing oxygen in the polymerization system in this way, the temperature is raised to 63° C. and the reaction is carried out for 10 hours. Then, it cools to room temperature, and obtains the homopolymer solution with a solid content concentration of 33 weight%. Next, this homopolymer solution is applied by casting onto a release liner and dried to prepare a test sample (sheet-shaped homopolymer) having a thickness of about 2 mm. This test sample was punched out into a disk shape with a diameter of 7.9 mm, sandwiched between parallel plates, and sheared at a frequency of 1 Hz using a viscoelasticity tester (manufactured by TA Instruments Japan, model name "ARES"), while applying a shear deformation of temperature range -70 ° C. The viscoelasticity is measured in shear mode at a temperature increase rate of ∼150°C and 5°C/min, and the temperature corresponding to the peak top temperature of tan δ is Tg of the homopolymer.

Although it does not specifically limit, It is suitable that the weight average molecular weight (Mw) of polymer A is about ^{20x10<4> or more normally.} According to the polymer A of such Mw, the adhesive which shows favorable cohesiveness is easy to be obtained. From the viewpoint of obtaining higher cohesive force, in some embodiments, the Mw of the polymer A ^{may be, for example, 30×10 4} or more, 40×10 ⁴ or more, 50×10 ⁴ or more, or 60×10 ⁴ or more may be sufficient, and 80×10 ⁴ or more may be sufficient. In addition, it is suitable that Mw of polymer A is about 500x10<^{4> or less normally.} Polymer A of such Mw easily forms an adhesive exhibiting moderate fluidity (movability of polymer chains), so it is suitable for realization of an adhesive sheet having a low adhesive force at the initial stage of pasting and a high adhesive force after mild heating. It is preferable from the viewpoint of improving the compatibility with the polymer B that the Mw of the polymer A is not too high. In some embodiments, the Mw of the polymer A ^{may be, for example, 250×10 4} or less, 200×10 ⁴ or less, or 150×10 ⁴ or less.

In addition, in this specification, Mw of the polymer A and the polymer B mentioned later can be calculated|required in terms of polystyrene by gel permeation chromatography (GPC). More specifically, Mw can be measured in accordance with the methods and conditions described in Examples to be described later.

As the polymer A in the pressure-sensitive adhesive sheet disclosed herein, an acrylic polymer can be preferably employed. When an acrylic polymer is used as the polymer A, good compatibility with the polymer B tends to be easily obtained. It is preferable that the compatibility of the polymer A and the polymer B is good, since it can contribute to the reduction of the initial adhesive force and the improvement of the adhesive force after heating through the improvement of the mobility of the polymer B in the pressure-sensitive adhesive layer.

The acrylic polymer is, for example, a polymer containing 50% by weight or more of monomer units derived from (meth)acrylic acid alkylester, that is, 50% by weight or more of the total amount of the monomer component (monomer raw material A) for preparing the acrylic polymer. It may be a polymer that is (meth)acrylic acid alkyl ester. As the (meth)acrylic acid alkyl ester, a (meth)acrylic acid alkyl ester having a C _1-20 (ie, C 1-20) linear or branched alkyl group can be preferably used. From the viewpoint of easy to balance the characteristics, _{the ratio of (meth)acrylic acid C 1-20} alkyl ester in the monomer raw material A may be, for example, 50% by weight or more, 60% by weight or more, and 70% by weight or more. do. From the same reason, the ratio of the (meth)acrylic acid C _1-20 alkylester in the monomer raw material A may be, for example, 99.9 wt% or less, 98 wt% or less, or 95 wt% or less. In some aspects, the ratio of the (meth)acrylic acid C _1-20 alkylester in the monomer raw material A may be, for example, 90% by weight or less, 85% by weight or less, or 80% by weight or less.

As a non-limiting example of the (meth)acrylic acid C _1-20 alkyl ester, (meth) methyl acrylate, (meth) ethyl acrylate, (meth) acrylic acid propyl, (meth) acrylate isopropyl, (meth) acrylate n-butyl, (meth) acrylate isobutyl, (meth) acrylate s-butyl, (meth) acrylate t-butyl, (meth) acrylate pentyl, (meth) acrylate isopentyl, (meth) acrylate hexyl, (meth) acrylate heptyl, (meth) acrylate ) octyl acrylate, (meth) acrylate 2-ethylhexyl, (meth) acrylate isooctyl, (meth) acrylate nonyl, (meth) acrylate isononyl, (meth) decyl acrylate, (meth) acrylate isodecyl, (meth) Undecyl acrylate, (meth) acrylate dodecyl, (meth) acrylic acid tridecyl, (meth) acrylic acid tetradecyl, (meth) acrylic acid pentadecyl, (meth) acrylic acid hexadecyl, (meth) acrylic acid heptadecyl, (meth) acrylic acid Stearyl, (meth)acrylic acid isostearyl, (meth)acrylic acid nonadecyl, (meth)acrylic acid eicosyl, etc. are mentioned.

Among these, it is preferable to use at least (meth)acrylic acid C _1-18 alkylester, and it is more preferable to use at least (meth)acrylic acid C _{1-14 alkylester.} In some embodiments, the acrylic polymer is _{at least one selected from (meth)acrylic acid C 4-12} alkyl ester (preferably acrylic acid C _4-10 alkyl ester, for example, acrylic acid C _6-10 alkyl ester) as a monomer. It can be contained as a unit. For example, an acrylic polymer containing one or both of n-butyl acrylate (BA) and 2-ethylhexyl acrylate (2EHA) is preferable, and an acrylic polymer containing at least 2EHA is particularly preferable. Examples of other (meth)acrylic acid C _1-18 alkyl esters that can be preferably used include methyl acrylate, methyl methacrylate (MMA), n-butyl methacrylate (BMA), and 2-ethylhexyl methacrylate (2EHMA). , isostearyl acrylate (ISTA), and the like.

The monomer raw material A may contain the other monomer (copolymerizable monomer) copolymerizable with (meth)acrylic acid alkylester as needed along with the (meth)acrylic-acid alkylester as a main component. As a copolymerizable monomer, the monomer which has a polar group (For example, a carboxy group, a hydroxyl group, a nitrogen atom containing ring, etc.) can be used suitably. A monomer having a polar group may be helpful in introducing a crosslinking point to the acrylic polymer or increasing the cohesive force of the acrylic polymer. A copolymerizable monomer can be used individually by 1 type or in combination of 2 or more type.

The following are mentioned as a non-limiting specific example of a copolymerizable monomer.

Hydroxyl group-containing monomers: for example, (meth)acrylic acid 2-hydroxyethyl, (meth)acrylic acid 2-hydroxypropyl, (meth)acrylic acid 2-hydroxybutyl, (meth)acrylic acid 3-hydroxypropyl, (meth)acrylic acid ) Acrylic acid 4-hydroxybutyl, (meth)acrylic acid 6-hydroxyhexyl, (meth)acrylic acid 8-hydroxyoctyl, (meth)acrylic acid 10-hydroxydecyl, (meth)acrylic acid 12-hydroxylauryl, ( (meth)acrylic acid hydroxyalkyl, such as 4-hydroxymethylcyclohexyl)methyl (meth)acrylate.

Monomers having a nitrogen atom-containing ring: for example, N-vinyl-2-pyrrolidone, N-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinyl Piperazine, N-vinylpyrazine, N-vinylpyrrole, N-vinylimidazole, N-vinyloxazole, N-(meth)acryloyl-2-pyrrolidone, N-(meth)acryloylpiperi Dean, N-(meth)acryloylpyrrolidine, N-vinylmorpholine, N-vinyl-3-morpholinone, N-vinyl-2-caprolactam, N-vinyl-1,3-oxazine-2 -one, N-vinyl-3,5-morpholinedione, N-vinylpyrazole, N-vinylisoxazole, N-vinylthiazole, N-vinylisothiazole, N-vinylpyridazine, etc.;

For example, N-(meth)acryloyloxymethylenesuccinimide, N-(meth)acryloyl-6-oxyhexamethylenesuccinimide, N-(meth)acryloyl-8-oxyhexamethylene monomers having a succinimide skeleton such as succinimide;

For example, Maleimides, such as N-cyclohexyl maleimide, N-isopropyl maleimide, N-lauryl maleimide, and N-phenyl maleimide; and,

For example, N-methylitaconimide, N-ethyl itaconimide, N-butyl itaconimide, N-octyl itaconimide, N-2-ethylhexyl itaconimide, N-cyclo Itaconimides, such as hexyl itaconimide and N-lauril itaconimide.

Carboxylic group-containing monomers: For example, acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid and the like.

Acid anhydride group-containing monomers: for example, maleic anhydride, itaconic anhydride.

Epoxy group-containing monomers: For example, epoxy group-containing acrylates such as (meth)acrylic acid glycidyl and (meth)acrylic acid-2-ethylglycidyl ether, allyl glycidyl ether, (meth)acrylic acid glycidyl ether, etc. .

Cyano group-containing monomers: for example, acrylonitrile, methacrylonitrile, and the like.

Isocyanate group-containing monomers: For example, 2-isocyanatoethyl (meth)acrylate and the like.

Amide group-containing monomers: for example, (meth)acrylamide; N,N-dimethyl (meth)acrylamide, N,N-diethyl (meth)acrylamide, N,N-dipropyl (meth)acrylamide, N,N-diisopropyl (meth)acrylamide, N, N,N-dialkyl(meth)acrylamide, such as N-di(n-butyl)(meth)acrylamide and N,N-di(t-butyl)(meth)acrylamide; N-alkyl (meth)acrylamide, such as N-ethyl (meth)acrylamide, N-isopropyl (meth)acrylamide, N-butyl (meth)acrylamide, and N-n-butyl (meth)acrylamide; N-vinylcarboxylic acid amides, such as N-vinylacetamide; Monomers having a hydroxyl group and an amide group, for example N-(2-hydroxyethyl)(meth)acrylamide, N-(2-hydroxypropyl)(meth)acrylamide, N-(1-hydroxypropyl)( Meth)acrylamide, N-(3-hydroxypropyl)(meth)acrylamide, N-(2-hydroxybutyl)(meth)acrylamide, N-(3-hydroxybutyl)(meth)acrylamide, N-hydroxyalkyl (meth)acrylamide, such as N-(4-hydroxybutyl) (meth)acrylamide; Monomers having an alkoxy group and an amide group, for example, N-alkoxyalkyl (meth) such as N-methoxymethyl (meth) acrylamide, N-methoxyethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide ) acrylamide; In addition, N,N-dimethylaminopropyl (meth)acrylamide, N-(meth)acryloylmorpholine, etc.

Aminoalkyl (meth)acrylic acid: For example, (meth)acrylic acid aminoethyl, (meth)acrylic acid N,N-dimethylaminoethyl, (meth)acrylic acid N,N-diethylaminoethyl, (meth)acrylic acid t- Butylaminoethyl.

Alkoxy group-containing monomers: for example, (meth)acrylic acid 2-methoxyethyl, (meth)acrylic acid 3-methoxypropyl, (meth)acrylic acid 2-ethoxyethyl, (meth)acrylic acid propoxyethyl, (meth) (meth)acrylic acid alkoxyalkyl, such as butoxyethyl acrylate and (meth)acrylic acid ethoxypropyl; (meth)acrylic acid alkoxyalkylene glycols, such as (meth)acrylic-acid methoxyethylene glycol and (meth)acrylic-acid methoxypolypropylene glycol.

Monomers containing a sulfonic acid group or a phosphoric acid group: for example, styrenesulfonic acid, allylsulfonic acid, sodium vinylsulfonate, 2-(meth)acrylamide-2-methylpropanesulfonic acid, (meth)acrylamidopropanesulfonic acid, sulfopropyl (meth) ) acrylate, (meth)acryloyloxynaphthalenesulfonic acid, 2-hydroxyethylacryloylphosphate, and the like.

(meth)acrylic acid ester having an alicyclic hydrocarbon group: For example, cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, and the like.

(meth)acrylic acid ester having an aromatic hydrocarbon group: For example, phenyl (meth)acrylate, phenoxyethyl (meth)acrylate, benzyl (meth)acrylate, and the like.

Vinyl ethers: For example, vinyl alkyl ethers such as methyl vinyl ether and ethyl vinyl ether.

Vinyl esters: For example, vinyl acetate, vinyl propionate, etc.

Aromatic vinyl compounds: For example, styrene, ?-methylstyrene, vinyltoluene, and the like.

Olefins: For example, ethylene, butadiene, isoprene, isobutylene, and the like.

In addition, heterocyclic (meth)acrylates such as (meth)acrylic acid tetrahydrofurfuryl, halogen atom-containing (meth)acrylates such as vinyl chloride and fluorine atom-containing (meth)acrylates, silicone (meth)acrylates Silicon atom-containing (meth)acrylates, such as (meth)acrylic acid ester obtained from terpene compound derivative alcohol.

When using such a copolymerizable monomer, although the usage-amount is not specifically limited, Usually, it is suitable to set it as 0.01 weight% or more of monomer raw material A. From the viewpoint of better exhibiting the effect of the use of the copolymerizable monomer, the amount of the copolymerizable monomer may be 0.1% by weight or more, or 1% by weight or more of the monomer raw material A. Moreover, the usage-amount of a copolymerizable monomer can be made into 50 weight% or less of monomer raw material A, and it is preferable to set it as 45 weight% or less. Thereby, it can prevent that the cohesive force of an adhesive becomes high too much, and can improve the tack feeling in normal temperature (25 degreeC). In some aspects, the usage-amount of a copolymerizable monomer may be 40 weight% or less of the monomer raw material A, and 35 weight% or less may be sufficient as it.

In some embodiments, the monomer raw material A may include a monomer having a nitrogen atom-containing ring. By use of the monomer which has a nitrogen atom containing ring, the cohesive force and polarity of an adhesive can be adjusted, and the adhesive force after mild heating can be improved suitably. By including a monomer having a nitrogen atom-containing ring in the monomer raw material A, the compatibility between the polymer A formed from the monomer raw material A and the polymer B tends to be improved. Thereby, it becomes easy to obtain the adhesive sheet which can raise adhesive force largely by mild heating.

The monomer having a nitrogen atom-containing ring may be appropriately selected from among the above examples, for example, and used alone or in combination of two or more. In some embodiments, the monomer raw material A preferably contains, as a monomer having a nitrogen atom-containing ring, at least one monomer selected from the group consisting of N-vinyl cyclic amides represented by the following general formula (M1). . The monomer raw material A is a monomer which has a nitrogen atom containing ring, and may contain only 1 type, or 2 or more types of these N-vinyl cyclic amides.

^{Here, R 1} in the general formula (M1) is a divalent organic group.

Specific examples of N-vinyl cyclic amide include N-vinyl-2-pyrrolidone, N-vinyl-2-piperidone, N-vinyl-3-morpholinone, N-vinyl-2-caprolactam, N-vinyl -1,3-oxazin-2-one, N-vinyl-3,5-morpholinedione, etc. are mentioned. Particularly preferred are N-vinyl-2-pyrrolidone and N-vinyl-2-caprolactam.

The usage-amount of the monomer which has a nitrogen atom containing ring is not restrict|limited in particular, Usually, it is suitable to set it as 0.01 weight% or more (preferably 0.1 weight% or more, for example, 0.5 weight% or more) of the monomer raw material A. In some aspects, the usage-amount of the monomer which has a nitrogen atom containing ring is good also as 1 weight% or more of monomer raw material A, It may be 5 weight% or more, It is good also as 10 weight% or more, It is good also as 12 weight% or more. do. In addition, from the viewpoint of improving the tackiness at room temperature (25° C.) and improving the flexibility at low temperature, it is appropriate that the amount of the monomer having a nitrogen atom-containing ring is usually 40% by weight or less of the monomer raw material A, 30 It is good also as weight% or less, it is good also as 20 weight% or less, and it is good also as 18 weight% or less.

Some preferable aspect WHEREIN: The monomer raw material A contains a hydroxyl-containing monomer. By use of a hydroxyl-containing monomer, the cohesive force and polarity of an adhesive can be adjusted, and the adhesive force after a mild heating can be improved suitably. In addition, the hydroxyl group-containing monomer provides a reaction point with a crosslinking agent (eg, an isocyanate-based crosslinking agent) described later, and can increase the cohesive force of the pressure-sensitive adhesive by the crosslinking reaction.

As a hydroxyl-containing monomer, (meth)acrylic acid 2-hydroxyethyl, (meth)acrylic acid 4-hydroxybutyl, (meth)acrylic acid 6-hydroxyhexyl, N-(2-hydroxyethyl) (meth)acrylamide, etc. can be used appropriately. Among these, 2-hydroxyethyl acrylate (HEA), 4-hydroxybutyl acrylate (4HBA), and N-(2-hydroxyethyl) acrylamide (HEAA) are mentioned as preferable examples.

The usage-amount of a hydroxyl-containing monomer is not restrict|limited in particular, Usually, it is suitable to set it as 0.01 weight% or more (preferably 0.1 weight% or more, for example, 0.5 weight% or more) of the monomer raw material A. In some aspects, the usage-amount of a hydroxyl-containing monomer is good also as 1 weight% or more of the monomer raw material A, good also as 5 weight% or more, and good also as 10 weight% or more. In addition, from the viewpoint of mobility in the pressure-sensitive adhesive layer of the polymer B, improved tack feeling at room temperature (25° C.), and improved flexibility at low temperature, the amount of the hydroxyl group-containing monomer to be used is usually 40% by weight or less of the monomer raw material A. It is suitable to set it as 30 weight% or less, and it is good also as 20 weight% or less, and good also as 10 weight% or less or 5 weight% or less.

In some embodiments, as the copolymerizable monomer, a monomer having a nitrogen atom-containing ring (eg, N-vinyl cyclic amide) and a hydroxyl group-containing monomer can be used in combination. In this case, the total amount of the monomer having a nitrogen atom-containing ring and the hydroxyl group-containing monomer may be, for example, 0.1 wt% or more of the monomer raw material A, 1 wt% or more, or 5 wt% or more, It is good also as 10 weight% or more, it is good also as 15 weight% or more, and it is good also as 20 weight% or more, and it is good also as 25 weight% or more. In addition, the total amount of the monomer which has a nitrogen atom containing ring, and a hydroxyl-containing monomer can be made into 50 weight% or less of monomer raw material A, for example, and it is preferable to set it as 40 weight% or less.

In the aspect in which the monomer raw material A contains a nitrogen atom-containing ring-containing monomer and a hydroxyl group-containing monomer in combination, the content (W _N ) of the nitrogen atom-containing ring-containing monomer and the hydroxyl group-containing monomer content in the monomer raw material A The relationship (based on weight) of (W _{OH ) is not particularly limited.} W _N /W _OH may be, for example, 0.01 or more, and usually 0.05 or more is suitable, 0.1 or more may be sufficient, 0.2 or more may be sufficient, 0.5 or more, and 0.7 or more may be sufficient as it. In addition, W _N / W is _OH, for example, and even less than 100, usually not more than 20, and suitable, and even more than 10, 5 or less, and even, and even less than 2, it is 1.5 or less even.

In some embodiments, the monomer raw material A does not contain a monomer having a polyorganosiloxane skeleton (monomer S1) which is preferably used as a constituent of the monomer raw material B described later (monomer S1), or the content of the monomer is 10 of the monomer raw material A It is preferable that it is less than weight % (more preferably less than 5 weight%, for example less than 2 weight%). According to the monomer raw material A of such a composition, the adhesive sheet which makes the rework property of an initial stage and the strong adhesiveness after adhesive force rise suitably compatible can be implement|achieved suitably. For the same reason, in some other embodiments, the monomer raw material A does not contain the monomer S1 or, when it contains the monomer S1, its content (by weight) is lower than the content of the monomer S1 in the monomer raw material B desirable.

The method of obtaining the polymer A is not specifically limited, For example, various polymerization methods, such as a solution polymerization method, an emulsion polymerization method, a bulk polymerization method, a suspension polymerization method, and a photopolymerization method, are employable suitably. In some embodiments, a solution polymerization method may be preferably employed. The polymerization temperature for solution polymerization can be appropriately selected depending on the type of monomer and solvent used, the type of polymerization initiator, etc., for example, about 20°C to 170°C (typically about 40°C to 140°C). can do.

The initiator used for polymerization can be suitably selected from conventionally well-known thermal polymerization initiator, a photoinitiator, etc. according to a polymerization method. A polymerization initiator can be used individually by 1 type or in combination of 2 or more type.

As the thermal polymerization initiator, for example, an azo polymerization initiator (for example, 2,2'-azobisisobutyronitrile, 2,2'-azobis-2-methylbutyronitrile, 2,2'-azo Bis(2-methylpropionic acid)dimethyl, 4,4'-azobis-4-cyanovaleric acid, azobisisovaleronitrile, 2,2'-azobis(2-amidinopropane)dihydrochloride, 2 ,2'-azobis[2-(5-methyl-2-imidazolin-2-yl)propane]dihydrochloride, 2,2'-azobis(2-methylpropionamidine) disulfate, 2, 2'-azobis(N,N'-dimethyleneisobutylamidine)dihydrochloride, etc.); persulfates such as potassium persulfate; peroxide polymerization initiators (eg, dibenzoyl peroxide, t-butyl permaleate, lauroyl peroxide, etc.); A redox-type polymerization initiator etc. are mentioned. The amount of the thermal polymerization initiator to be used is not particularly limited, but for example, 0.01 parts by weight to 5 parts by weight, preferably 0.05 parts by weight to 100 parts by weight of the monomer component (monomer raw material A) used in the preparation of the acrylic polymer. It can be set as the quantity within the range of 3 weight part.

Although it does not restrict|limit especially as a photoinitiator, For example, A benzoin ether type photoinitiator, an acetophenone type photoinitiator, alpha-ketol type photoinitiator, an aromatic sulfonyl chloride type|system|group photoinitiator, a photoactive oxime type photoinitiator, a benzoin type. A photoinitiator, a benzyl photoinitiator, a benzophenone photoinitiator, a ketal photoinitiator, a thioxanthone photoinitiator, an acylphosphine oxide photoinitiator, etc. can be used. Although the usage-amount of a photoinitiator is not specifically limited, For example, it is 0.01 weight part - 5 weight part with respect to 100 weight part of monomer raw materials A, Preferably it can be made into the amount within the range of 0.05 weight part - 3 weight part.

In some embodiments, the polymer A is in the form of a partial polymerization product (polymer syrup) obtained by polymerizing a part of the monomer component by irradiating ultraviolet (UV) rays to a mixture containing a polymerization initiator in the monomer raw material A as described above. It may be included in the pressure-sensitive adhesive composition for forming a layer. Polymerization can be completed by applying the pressure-sensitive adhesive composition including such a polymer syrup to a predetermined to-be-coated object and irradiating ultraviolet rays. That is, the polymer syrup may be identified as a precursor of polymer A. The pressure-sensitive adhesive layer disclosed herein may be formed using, for example, the pressure-sensitive adhesive composition including the polymer syrup and the polymer B.

(Polymer B)

Polymer B in the technique disclosed herein is a copolymer of a monomer having a polyorganosiloxane skeleton (hereinafter also referred to as "monomer S1") and a (meth)acrylic monomer. Polymer B suppresses the adhesive force at the initial stage of sticking to the adherend due to the low polarity and mobility of the polyorganosiloxane structure derived from the monomer S1, and also increases the adhesive force to the adherend by heating. can function as zero. It does not specifically limit as monomer S1, Arbitrary monomers containing polyorganosiloxane frame|skeleton can be used. The monomer S1 promotes the localization of the polymer B on the surface of the pressure-sensitive adhesive layer in the pressure-sensitive adhesive sheet before use (before sticking to the adherend) due to the low polarity derived from the structure, and provides light peelability (low tackiness) at the initial stage of bonding. ) is expressed. As the monomer S1, one having a structure having a polymerizable reactive group at one end can be preferably used. According to the copolymerization of the monomer S1 and the (meth)acrylic monomer, the polymer B having a polyorganosiloxane skeleton in the side chain is formed. Polymer B having such a structure tends to have low initial adhesive strength and high adhesive strength after mild heating due to side chain mobility and ease of movement. In addition, in some aspects, as monomer S1, one which has a polymerizable reactive group at one terminal and does not have a functional group which crosslinking reaction with polymer A generate|occur|produces at the other terminal can be employ|adopted preferably. The polymer B copolymerized with the monomer S1 having such a structure tends to have low initial adhesive strength and high adhesive strength after heating due to the mobility of the polyorganosiloxane structure derived from the monomer S1.

As the monomer S1, for example, a compound represented by the following general formula (1) or (2) can be used. More specifically, X-22-174ASX, X-22-2426, X-22-2475, KF-2012 etc. are mentioned as a single-terminal reactive silicone oil manufactured by Shin-Etsu Chemical Co., Ltd. Monomer S1 can be used individually by 1 type or in combination of 2 or more type.

^{Here, R 3} in the general formulas (1) and (2) is hydrogen or methyl, R ⁴ is a methyl group or a monovalent organic group, and m and n are integers of 0 or more.

The functional group equivalent of the monomer S1 may be an appropriate value within the range in which a desired effect is exhibited using the monomer S1, and is not limited to a specific range. From the viewpoint of sufficiently suppressing the initial adhesive force, the functional group equivalent is, for example, 100 g/mol or more, 200 g/mol or more, 300 g/mol or more (for example, 500 g/mol or more), and 700 g/mol or more. It is preferable, it is more preferable that it is 800 g/mol or more, It is more preferable that it is 850 g/mol or more, It is especially preferable that it is 1500 g/mol or more. In some embodiments, from the viewpoint of coexistence of low tackiness at the initial stage of pasting and an increase in adhesive strength after mild heating, the functional group equivalent may be 3000 g/mol or more, 4500 g/mol or more, 6000 g/mol or more, or 9000 g /mol or more may be sufficient, 12000 g/mol or more may be sufficient, and 15000 g/mol or more (for example, 16000 g/mol or more) may be sufficient. The functional group equivalent of the monomer S1 may be, for example, 50000 g/mol or less. From a viewpoint of fully raising adhesive force, it is preferable that it is 30000 g/mol or less, for example, and, as for the said functional group equivalent, it is more preferable that it is 20000 g/mol or less. In some embodiments, the functional group equivalent of the monomer S1 may be less than 18000 g/mol, less than 15000 g/mol, less than 10000 g/mol, less than 6000 g/mol, or less than 5000 g/mol. When the functional group equivalent of the monomer S1 is within the above range, it is easy to adjust the compatibility (for example, compatibility with the base polymer) and mobility in the pressure-sensitive adhesive layer to an appropriate range, and the initial low tackiness and the adhesive strength increase after mild heating It becomes easy to implement|achieve the adhesive layer which is compatible with

Non-limiting examples of the suitable range of the functional group equivalent of the monomer S1 include 700 g/mol or more and 50000 g/mol or less, 700 g/mol or more and 30000 g/mol or less, 700 g/mol or more and 20000 g/mol or less, 700 g/mol or more and less than 18000 g/mol. , 700 g/mol or more and less than 15000 g/mol, 800 g/mol or more and less than 10000 g/mol, 850 g/mol or more and less than 6000 g/mol, 1500 g/mol or more and less than 5000 g/mol. In some embodiments, the suitable range of the functional group equivalent of the monomer S1 may be 3000 g/mol or more and 50000 g/mol or less, 6000 g/mol or more and 50000 g/mol or less, 12000 g/mol or more and 50000 g/mol or less, 15000 g/mol or more and 50000 g/mol or less. have.

Here, "functional group equivalent" means the weight of the main skeleton (for example, polydimethylsiloxane) couple|bonded per one functional group. Regarding the notation unit g/mol, it is converted into 1 mol of the functional group. The functional group equivalent of the monomer S1 ^{can be calculated from, for example, the spectral intensity of 1} H-NMR (proton NMR) based on nuclear magnetic resonance (NMR). Calculation of the functional group equivalent (g/mol) of the monomer S1 based on the spectral intensity of ^{1 H-NMR is based on a general structural analysis method related to 1} H-NMR spectral analysis, if necessary, described in Japanese Patent No. 5951153 can be done with reference to

In addition, when using two or more types of monomers from which functional group equivalent differs as monomer S1, an arithmetic average value can be used as functional group equivalent of monomer S1. That is, the functional group equivalent of the monomer S1 including n types of monomers (monomer S1 ₁ , monomer S1 ₂ ... monomer S1 _n ) having different functional group equivalents can be calculated by the following formula.

Functional group equivalent weight of the monomer S1 of the functional group equivalent weight (g / mol) = (monomer S1 ₁ of the functional group equivalent weight × monomer S1 ₁ the amount + monomer S1 ₂ of the functional group equivalent weight × monomer S1 ₂ amount + a ... + monomer S1 _n × monomer S1 _n of)/(the amount of the monomer S1 ₁ + the amount of the monomer S1 ₂ + … + the amount of the _{monomer S1 n)}

An appropriate value can be employ|adopted for content of monomer S1 in the range where the desired effect is exhibited using this monomer S1, and it is not limited to a specific range. In some embodiments, in the total amount of the monomer component (monomer raw material B) for preparing the polymer B, for example, may be 5% by weight or more, and from the viewpoint of better exhibiting the effect as an adhesive strength increase retardant, 10% by weight or more It is preferable to do it, and it is good also as 15 weight% or more, and good also as 20 weight% or more. In addition, the content of the monomer S1 in the monomer raw material B may be, for example, 80% by mass or less, preferably 60% by weight or less, and may be 50% by weight or less from the viewpoint of polymerization reactivity and compatibility, It is good also as 40 weight% or less and good also as 30 weight% or less. When the content of the monomer S1 is less than 5% by weight, the initial adhesive force may not be sufficiently suppressed in some cases. When there is more content of monomer S1 than 60 weight%, the raise of adhesive force may become inadequate.

In addition to the monomer S1, the monomer raw material B contains a (meth)acrylic monomer copolymerizable with the monomer S1. By copolymerizing 1 type or 2 or more types of (meth)acrylic-type monomer and monomer S1, the mobility of the polymer B in an adhesive layer can be suitably adjusted. Copolymerizing the monomer S1 and the (meth)acrylic monomer may also help improve the compatibility between the polymer B and the polymer A (eg, an acrylic polymer).

As a (meth)acrylic-type monomer which can be used for the monomer raw material B, (meth)acrylic-acid alkylester is mentioned, for example. For example, when the polymer A is an acrylic polymer, one or two or more of the monomers exemplified above as the (meth)acrylic acid alkylester that can be used can be used as a constituent component of the monomer raw material B. In some embodiments, the monomer raw material B is a (meth)acrylic acid C _4-12 alkyl ester (preferably (meth)acrylic acid C _4-10 alkyl ester, for example (meth)acrylic acid C _6-10 alkyl ester). It may contain at least 1 type. In some other embodiments, the monomer raw material B is at least 1 of _{methacrylic acid C 1-18} alkyl ester (preferably methacrylic acid C _1-14 alkyl ester, for example, methacrylic acid C _{1-10 alkyl ester).} may contain species. The monomer raw material B may include, as a (meth)acrylic monomer, one or two or more selected from, for example, MMA, BMA, and 2EHMA.

As another example of the said (meth)acrylic-type monomer, the (meth)acrylic acid ester which has an alicyclic hydrocarbon group is mentioned. For example, cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, 1-adamantyl (meth) acrylate, etc. Can be used. In some embodiments, the monomer raw material B may contain, as a (meth)acrylic monomer, at least one selected from dicyclopentanyl methacrylate, isobornyl methacrylate and cyclohexyl methacrylate.

The content of the (meth)acrylic acid alkyl ester and the (meth)acrylic acid ester having an alicyclic hydrocarbon group in the monomer raw material B may be, for example, 10 wt% or more and 95 wt% or less, and 20 wt% or more and 95 wt% It may be below, 30 weight% or more and 90 weight% or less may be sufficient, 40 weight% or more and 90 weight% or less may be sufficient, and 50 weight% or more and 85 weight% or less may be sufficient. From the viewpoint of easiness of increasing the adhesive force by mild heating, the use of (meth)acrylic acid alkylester may be advantageous. In some embodiments, the content of (meth)acrylic acid ester having an alicyclic hydrocarbon group may be less than 50% by weight, less than 30% by weight, less than 15% by weight, or less than 10% by weight of the monomer raw material B. , may be less than 5% by weight. It is not necessary to use the (meth)acrylic acid ester which has an alicyclic hydrocarbon group.

In some preferred embodiments, the (meth)acrylic monomer, which is a component of the monomer raw material B, may include a monomer M2 in which the Tg of the homopolymer is 50° C. or higher. In the polymer B, by copolymerizing the monomer S1 and the monomer M2, the mobility and mobility of the polyorganosiloxane structural moiety accompanying the temperature rise are appropriately controlled, and the initial light peelability (reworkability) and the increase in adhesive strength after mild heating. It is easy to realize compatibility. In some embodiments, the homopolymer Tg of the monomer M2 may be 60°C or higher, 70°C or higher, 80°C or higher, or 90°C or higher. In addition, the upper limit of the homopolymer Tg of the monomer M2 is not particularly limited, but from the viewpoint of the ease of synthesis of the polymer B and the like, it is usually suitable to be 200°C or less. In some embodiments, the homopolymer Tg of the monomer M2 may be, for example, 180°C or lower, 150°C or lower, or 120°C or lower.

As the monomer M2, for example, among the (meth)acrylic monomers exemplified above, those satisfying the conditions for Tg of the homopolymer can be used. For example, one or more monomers selected from the group consisting of (meth)acrylic acid alkyl esters and (meth)acrylic acid esters having an alicyclic hydrocarbon group can be used. As (meth)acrylic acid alkylester, the C1-C4 alkyl methacrylic acid ester of an alkyl group is employable preferably.

In the aspect in which the monomer raw material B contains the monomer M2, the content of the monomer M2 may be, for example, 5 weight% or more, 10 weight% or more, 15 weight% or more, 20 weight% or more of the monomer raw material B. or more may be sufficient, 25 weight% or more may be sufficient, and 30 weight% or more may be sufficient. In some embodiments, the content of the monomer M2 may be 35 wt% or more, 40 wt% or more, 45 wt% or more, 50 wt% or more, or 55 wt% or more of the monomer raw material B. . Further, the content of the monomer M2 may be, for example, 90% by weight or less, usually 80% by weight or less is suitable, preferably 75% by weight or less, 70% by weight or less, or 65% by weight or less. . In some preferred embodiments, the content of monomer M2 is 60% by weight or less (eg 50% by weight or less, typically 42% by weight or less). In the polymer B, since the copolymerization ratio of the monomer M2 of Tg50°C or higher is limited to a predetermined value or less, an increase in adhesive strength after mild heating can be preferably realized based on the mobility of the polymer B in the vicinity of 50°C. From a similar viewpoint, the content of the monomer M2 in the monomer raw material B may be 35 weight% or less, 25 weight% or less may be sufficient, and 15 weight% or less (for example, 5 weight% or less) may be sufficient.

The content of the monomer M2 is, for example, the monomer M2 is selected from the group consisting of (meth) acrylic acid alkyl ester and (meth) acrylic acid ester having the alicyclic hydrocarbon group An aspect containing one or two or more monomers, Monomer M2 can be preferably applied in an embodiment including one or two or more monomers selected from (meth)acrylic acid alkyl esters (eg, methacrylic acid alkyl esters). As a suitable example of this aspect, an aspect in which the monomer M2 contains MMA may be mentioned.

In some aspects, the said (meth)acrylic-type monomer may contain the monomer M3 whose Tg of a homopolymer is less than 50 degreeC (typically -20 degreeC or more and less than 50 degreeC). By use of monomer M3, it becomes easy to obtain the adhesive sheet which makes adhesive force and cohesive force compatible in good balance after an adhesive force rise. From a viewpoint of making it easy to exhibit such an effect, it is preferable to use the monomer M3 in combination with the monomer M2.

As the monomer M3, for example, from among the (meth)acrylic monomers exemplified above, those satisfying the conditions for Tg of the homopolymer can be used. For example, one or more monomers selected from the group consisting of (meth)acrylic acid alkyl esters can be used.

In the aspect in which the monomer raw material B contains the monomer M3, the content of the monomer M3 may be, for example, 5 weight% or more, 10 weight% or more, 15 weight% or more, 20 weight% or more of the monomer raw material B. or more may be sufficient, 25 weight% or more may be sufficient, 30 weight% or more may be sufficient, and 35 weight% or more may be sufficient. In addition, it is suitable that content of monomer M3 shall normally be 70 weight% or less of monomer raw material B, and may be 60 weight% or less, and may be 50 weight% or less. The content of the monomer M3 may be preferably applied, for example, in an embodiment in which the monomer M3 consists of one or two or more monomers selected from (meth)acrylic acid alkyl esters (eg, methacrylic acid alkyl esters). .

In some aspects of the adhesive sheet disclosed herein, in the monomer raw material B, it is preferable that the content of the monomer having a homopolymer Tg higher than 170°C is 30% by weight or less. Here, in the present specification, unless otherwise specified, that the content of the monomer is X% by weight or less is a concept including an embodiment in which the content of the monomer is 0% by weight, that is, an embodiment substantially not containing the monomer. In addition, "not substantially included" means that the said monomer is not used intentionally at least. When the copolymerization ratio of monomers having a Tg of the homopolymer higher than 170°C becomes high, the mobility of the polymer B tends to become insufficient, and it may be difficult to increase the adhesive force by heating to a temperature range higher than 50°C.

In some embodiments, the monomer raw material B preferably contains at least MMA as a (meth)acrylic monomer. According to the polymer B in which MMA was copolymerized, an _{adhesive sheet with large N 50} is easy to be obtained. The ratio of MMA to the total amount of (meth)acrylic monomers contained in the monomer raw material B may be, for example, 5% by weight or more, 10% by weight or more, 20% by weight or more, 30% by weight or more. , 40% by weight or more may be sufficient. In some embodiments, the ratio of MMA to the total amount of the (meth)acrylic monomer may be, for example, more than 50% by weight, more than 55% by weight, more than 60% by weight, or more than 65% by weight. , more than 70% by weight may be sufficient. Moreover, as for the ratio of MMA to the total amount of the said (meth)acrylic-type monomer, 95 weight% or less is suitable normally, 90 weight% or less may be sufficient, and 85 weight% or less may be sufficient as it. In some preferred embodiments, the ratio of MMA to the total amount of the (meth)acrylic monomer may be 75% by weight or less, 65% by weight or less, or 60% by weight or less from the viewpoint of increasing the adhesive strength after mild heating. , 55 wt% or less (for example, 50 wt% or less) may be sufficient.

As another example of a monomer that can be included together with the monomer S1 as a monomer unit constituting the polymer B, the carboxyl group-containing monomer exemplified above as a monomer that can be used when the polymer A is an acrylic polymer, an acid anhydride group-containing monomer, a hydroxyl group-containing monomer Monomers, epoxy group-containing monomers, cyano group-containing monomers, isocyanate group-containing monomers, amide group-containing monomers, nitrogen atom-containing monomers (N-vinyl cyclic amides, monomers with succinimide skeletons, maleimides, itaconimis) Drew, etc.), (meth)acrylic acid aminoalkyls, vinyl esters, vinyl ethers, olefins, (meth)acrylic acid esters having an aromatic hydrocarbon group, heterocyclic-containing (meth)acrylates, halogen atom-containing (meth)acrylates and (meth)acrylic acid esters obtained from terpene compound derivative alcohols.

As another example of a monomer that may be included together with the monomer S1 as a monomer unit constituting the polymer B, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate , oxyalkylene di(meth)acrylates such as polyethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, and tripropylene glycol di(meth)acrylate; A monomer having a polyoxyalkylene skeleton, for example, has a polymerizable functional group such as a (meth)acryloyl group, a vinyl group, an allyl group at one end of a polyoxyalkylene chain such as polyethylene glycol or polypropylene glycol, and the other polymerizable polyoxyalkylene ethers having an ether structure (such as alkyl ether, aryl ether, aryl alkyl ether) at the terminal; (meth)acrylic acid alkoxyalkyl, such as (meth)acrylic-acid methoxyethyl, (meth)acrylic-acid ethoxyethyl, (meth)acrylic-acid propoxyethyl, (meth)acrylic-acid butoxyethyl, (meth)acrylic-acid ethoxypropyl; salts such as (meth)acrylic acid alkali metal salts; polyvalent (meth)acrylates such as trimethylolpropane tri(meth)acrylic acid ester: vinyl halide compounds such as vinylidene chloride and 2-chloroethyl (meth)acrylic acid; oxazoline group-containing monomers such as 2-vinyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, and 2-isopropenyl-2-oxazoline; aziridine group-containing monomers such as (meth)acryloylaziridine and (meth)acrylic acid-2-aziridinylethyl; hydroxyl group-containing vinyl monomers such as (meth)acrylic acid-2-hydroxyethyl, (meth)acrylic acid-2-hydroxypropyl, and adducts of lactones and (meth)acrylic acid-2-hydroxyethyl; fluorine-containing vinyl monomers such as fluorine-substituted (meth)acrylic acid alkyl esters; Reactive halogen-containing vinyl monomers, such as 2-chloroethyl vinyl ether and monochloro vinyl acetate; Organic silicon-containing vinyl monomers such as vinyltrimethoxysilane, γ-(meth)acryloxypropyltrimethoxysilane, allyltrimethoxysilane, trimethoxysilylpropylallylamine, and 2-methoxyethoxytrimethoxysilane ; In addition, macromonomers which have a radically polymerizable vinyl group at the monomer terminal which superposed|polymerized the vinyl group; and the like. These can be copolymerized with monomer S1 individually by 1 type or in combination of 2 or more types.

In some embodiments, as the polymer B, a polymer B that does not have a functional group causing a crosslinking reaction with the polymer A can be preferably employed. In other words, it is preferable that the polymer B is contained in the adhesive layer in the form which is not chemically bonded with the polymer A. The adhesive layer containing the polymer B in such a form has good mobility of the polymer B at the time of heating, and is suitable for the improvement of the adhesive force increase ratio. The functional group in which the crosslinking reaction occurs with the polymer A may vary depending on the type of the functional group of the polymer A, but may be, for example, an epoxy group, an isocyanate group, a carboxy group, an alkoxysilyl group, or an amino group.

Mw of the polymer B is not particularly limited. Mw of the polymer B may be, for example, 1000 or more, or 5000 or more. Mw of the polymer B may be, for example, 10,000 or more, 12,000 or more, 15,000 or more, or 20,000 or more from a viewpoint of suitably expressing the rise in adhesive force after mild heating. In some aspects, Mw of polymer B may be 50,000 or more, 80,000 or more, 100,000 or more, and 120,000 or more (for example, 150,000 or more) may be sufficient as it. The upper limit of Mw of the polymer B may be, for example, 500,000 or less, 350,000 or less, 350,000 or less, or less than 100,000. Mw of polymer B may be less than 80,000, may be less than 70,000, may be less than 50,000, from the viewpoint of adjusting the compatibility and mobility in the pressure-sensitive adhesive layer to an appropriate range, and suitably expressing an increase in adhesive strength after mild heating, Less than 40,000 may be sufficient, and less than 20,000 may be sufficient, Furthermore, less than 10,000 may be sufficient.

In some preferred embodiments, Mw of polymer B is preferably lower than Mw of polymer A. Thereby, it becomes easy to implement|achieve the adhesive sheet which makes the favorable rework property of pasting initial stage, and the adhesive force rise after a mild heating compatible. Mw of polymer B may be, for example, 0.8 times or less, 0.75 times or less, 0.5 times or less, 0.3 times or less, 0.1 times or less, or 0.05 times or less of Mw of polymer A, for example, 0.03 times or less (for example, 0.02 times or less) may be sufficient.

The polymer B can be produced by, for example, polymerizing the above-mentioned monomers by known methods such as solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization, and photopolymerization.

In order to adjust the molecular weight of polymer B, a chain transfer agent can be used as needed. Examples of the chain transfer agent to be used include compounds having a mercapto group such as octyl mercaptan, lauryl mercaptan, t-nonyl mercaptan, t-dodecyl mercaptan, mercaptoethanol and α-thioglycerol; Thioglycolic acid, methyl thioglycolate, ethyl thioglycolate, propyl thioglycolate, butyl thioglycolate, thioglycolic acid t-butyl, thioglycolic acid 2-ethylhexyl, thioglycolate octyl, thioglycolic acid isooctyl, thioglycolic acid esters such as decyl thioglycolate, dodecyl thioglycolate, thioglycolic acid ester of ethylene glycol, thioglycolic acid ester of neopentyl glycol, and thioglycolic acid ester of pentaerythritol; α-methylstyrene dimer; and the like.

The amount of the chain transfer agent to be used is not particularly limited, but the amount of the chain transfer agent is usually 0.05 to 20 parts by weight, preferably 0.1 to 15 parts by weight, more preferably 0.2 parts by weight to 100 parts by weight of the monomer. It contains 10 parts by weight. Thus, by adjusting the addition amount of a chain transfer agent, the polymer B of suitable molecular weight can be obtained. A chain transfer agent can be used individually by 1 type or in combination of 2 or more type.

As a means for adjusting the molecular weight of polymer B, various conventionally well-known means including the use of the said chain transfer agent can be used individually or in combination as appropriate. The same is true for the molecular weight of polymer A. Non-limiting examples of such means include selection of a polymerization method, selection of a type and amount of polymerization initiator, selection of polymerization temperature, selection of a type and amount of polymerization solvent in solution polymerization method, and selection of a polymerization solvent in the photopolymerization method. selection of light irradiation intensity, and the like. Those skilled in the art can understand how to obtain a polymer having a desired molecular weight based on the description of the present specification including the specific examples described below and the technical common sense at the time of filing the present application.

In the adhesive sheet disclosed herein, the usage-amount of polymer B with respect to 100 weight part of usage-amounts of polymer A can be made into 0.1 weight part or more, for example, and may be 0.5 weight part or more from a viewpoint of obtaining a higher effect. , It is good also as 1 weight part or more, and good also as 2 weight part or more. Some aspects WHEREIN: From a viewpoint of rework property improvement etc., the usage-amount of the said polymer B may be 3 weight part or more, and may be 4 weight part or more, and may be 5 weight part or more. In addition, the usage-amount of polymer B with respect to 100 weight part of usage-amounts of polymer A may be 75 weight part or less, 60 weight part or less may be sufficient, and 50 weight part or less may be sufficient, for example. From the viewpoint of avoiding excessive lowering of the cohesive force of the pressure-sensitive adhesive layer, in some embodiments, the amount of the polymer B used relative to 100 parts by weight of the polymer A may be, for example, 40 parts by weight or less, 35 parts by weight or less, 30 parts by weight or less It is good also as a weight part or less or 25 weight part or less. From the viewpoint of obtaining higher adhesive strength after heating, in some embodiments, the amount of the polymer B used may be 20 parts by weight or less, 17 parts by weight or less, 15 parts by weight or less, and 12 parts by weight or less. You may be good also, good also as 10 weight part or less, good as 8 weight part or less, good as 6 weight part or less, good also as 4 weight part or less (for example, 3 weight part or less).

The pressure-sensitive adhesive layer can contain, as needed, a polymer (arbitrary polymer) other than the polymer A and the polymer B within a range that does not significantly impair the performance of the pressure-sensitive adhesive sheet disclosed herein. As for the usage-amount of such an arbitrary polymer, it is suitable to set it as 20 weight% or less of the whole polymer component normally contained in an adhesive layer, 15 weight% or less may be sufficient and 10 weight% or less may be sufficient as it. In some aspects, the usage-amount of the said arbitrary polymer may be 5 weight% or less, 3 weight% or less, and 1 weight% or less of the whole polymer component may be sufficient. The adhesive layer which does not contain polymers other than the polymer A and the polymer B substantially may be sufficient.

(crosslinking agent)

In the pressure-sensitive adhesive layer, a crosslinking agent may be used as needed for the purpose of adjusting cohesive force or the like. As the crosslinking agent, a known crosslinking agent can be used in the field of pressure-sensitive adhesives, for example, an epoxy-based crosslinking agent, an isocyanate-based crosslinking agent, a silicone-based crosslinking agent, an oxazoline-based crosslinking agent, an aziridine-based crosslinking agent, a silane-based crosslinking agent, an alkyl etherified melamine-based crosslinking agent, A metal chelate type crosslinking agent etc. are mentioned. In particular, an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent, and a metal chelate-based crosslinking agent can be suitably used. A crosslinking agent can be used individually by 1 type or in combination of 2 or more type.

Specifically, examples of the isocyanate-based crosslinking agent include tolylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, The adduct body of polyols, such as tetramethylxylylene diisocyanate, naphthalene diisocyanate, triphenylmethane triisocyanate, polymethylene polyphenyl isocyanate, and a trimethylol propane, is mentioned. Alternatively, a compound having at least one isocyanate group and one or more unsaturated bonds in one molecule, specifically, 2-isocyanatoethyl (meth)acrylate, etc. can also be used as the isocyanate-based crosslinking agent. These can be used individually by 1 type or in combination of 2 or more type.

Examples of the epoxy crosslinking agent include bisphenol A, epichlorohydrin type epoxy resin, ethylene glycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, 1,6-hexanediol Glycidyl ether, trimethylolpropane triglycidyl ether, diglycidylaniline, diamine glycidylamine, N,N,N',N'-tetraglycidyl-m-xylylenediamine and 1,3 -bis(N,N-diglycidylaminomethyl)cyclohexane etc. are mentioned. These can be used individually by 1 type or in combination of 2 or more type.

As a metal chelate compound, aluminum, iron, tin, titanium, nickel, etc. as a metal component, acetylene, methyl acetoacetate, ethyl lactate etc. are mentioned as a chelate component. These can be used individually by 1 type or in combination of 2 or more type.

The usage-amount in the case of using a crosslinking agent is not specifically limited, For example, it can be set as the quantity exceeding 0 weight part with respect to 100 weight part of polymer A. In addition, the usage-amount of a crosslinking agent can be made into 0.01 weight part or more with respect to 100 weight part of polymers A, and it is preferable to set it as 0.05 weight part or more. By increase in the usage-amount of a crosslinking agent, the adhesive force in the initial stage of pasting is suppressed, and there exists a tendency for rework property to improve. In some aspects, the usage-amount of the crosslinking agent with respect to 100 weight part of polymer A may be 0.1 weight part or more, 0.5 weight part or more may be sufficient, and 0.8 weight part or more may be sufficient. On the other hand, from the viewpoint of obtaining an increase in adhesive strength after mild heating by allowing the mobility of the polymer B appropriately, the amount of the crosslinking agent to be used relative to 100 parts by weight of the polymer A is usually 15 parts by weight or less, and 10 parts by weight or less. You may do it, and it is good also as 5 weight part or less.

The technique disclosed herein can be preferably implemented in an embodiment using at least an isocyanate-based crosslinking agent as a crosslinking agent. From the viewpoint of achieving both good reworkability at the initial stage of pasting and increase in adhesive strength after mild heating, in some embodiments, the amount of the isocyanate-based crosslinking agent to be used relative to 100 parts by weight of polymer A may be, for example, 0.01 parts by weight or more, and 0.05 It is good also as a weight part or more, it is good also as 0.1 weight part or more, and it is good also as 0.2 weight part or more (for example, 0.3 weight part or more), and can also be set as 5 weight part or less, for example, can be set as 5 weight part or less, 3 weight part or less It may be good, and it is good also as 1.5 weight part or less, and it is good also as 1.2 weight part or less, and is good also as 0.8 weight part or less (for example, 0.6 weight part or less).

Although not particularly limited, when an isocyanate-based crosslinking agent is used in a configuration in which the pressure-sensitive adhesive layer includes a hydroxyl group-containing monomer as a monomer unit, the amount of the isocyanate-based crosslinking agent W and the amount of the hydroxyl group-containing monomer with respect to _{NCO W OH} is , W _OH /W _NCO can be set to an amount of 2 or more. As such, by increasing the amount of the hydroxyl group-containing monomer to the isocyanate-based crosslinking agent, a crosslinked structure suitable for greatly increasing the adhesive strength after mild heating with respect to the adhesive strength at the initial stage of pasting can be formed. In some embodiments, W _OH /W _NCO may be 3 or more, 5 or more, 10 or more, 20 or more, 30 or more, or 50 or more. The upper limit of W _OH /W _NCO is not particularly limited, and from the viewpoint of setting the degree of crosslinking that allows moderate movement of polymer B by mild heating, W _OH /W _NCO may be, for example, 500 or less, and 200 or less. and may be 100 or less, or may be 50 or less.

In order to advance any of the crosslinking reactions mentioned above more effectively, you may use a crosslinking catalyst. As the crosslinking catalyst, for example, a tin-based catalyst (especially dioctyl tin dilaurate) can be preferably used. The amount of the crosslinking catalyst to be used is not particularly limited, but may be, for example, approximately 0.0001 parts by weight to 1 part by weight based on 100 parts by weight of the polymer A.

A polyfunctional monomer may be used for an adhesive layer as needed. The polyfunctional monomer may be useful for purposes such as adjustment of cohesive force by being used instead of or in combination with the crosslinking agent as described above. For example, in the pressure-sensitive adhesive layer formed of the photo-curable pressure-sensitive adhesive composition, a polyfunctional monomer may be preferably used.

Examples of the polyfunctional monomer include ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, neopentyl glycol di( Meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, ethylene glycol di (meth) acrylate, 1,6-hexane Diol di (meth) acrylate, 1,12-dodecanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylol methane tri (meth) acrylate, allyl (meth) acrylate, vinyl (meth)acrylate, divinylbenzene, epoxy acrylate, polyester acrylate, urethane acrylate, butyldiol (meth)acrylate, hexyldiol di(meth)acrylate, etc. are mentioned. Among them, trimethylolpropane tri(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and dipentaerythritol hexa(meth)acrylate can be preferably used. A polyfunctional monomer can be used individually by 1 type or in combination of 2 or more type.

Although the usage-amount of a polyfunctional monomer changes with the molecular weight, the number of functional groups, etc., it is usually suitable to set it as the range of about 0.01 weight part - 3.0 weight part with respect to 100 weight part of polymer A. In some aspects, the usage-amount of a polyfunctional monomer may be, for example, 0.02 weight part or more may be sufficient with respect to 100 weight part of polymer A, and 0.03 weight part or more may be sufficient. By increase in the usage-amount of a polyfunctional monomer, the adhesive force of an initial stage of pasting is suppressed, and there exists a tendency for rework property to improve. On the other hand, from the viewpoint of controlling the movement of polymer B with a cross-linked network while controlling the increase in adhesive strength after mild heating while ensuring the mobility of the polymer B, the amount of the polyfunctional monomer used may be 2.0 parts by weight or less with respect to 100 parts by weight of the polymer A, 1.0 weight part or less may be sufficient and 0.5 weight part or less may be sufficient.

(Tackifying resin)

A tackifying resin can be included in an adhesive layer as needed. Although it does not restrict|limit especially as tackifying resin, For example, Rosin type tackifying resin, terpene type tackifying resin, phenol type tackifying resin, hydrocarbon type tackifying resin, ketone type tackifying resin, polyamide type tackifying resin. , epoxy-based tackifying resin, elastomer-based tackifying resin, and the like. Tackifying resin can be used individually by 1 type or in combination of 2 or more type.

Examples of the rosin-based tackifying resin include unmodified rosin (raw rosin) such as gum rosin, wood rosin, and tall oil rosin, and modified rosin obtained by modifying these unmodified rosins by polymerization, disproportionation, hydrogenation, or the like ( polymerized rosin, stabilized rosin, disproportionated rosin, fully hydrogenated rosin, partially hydrogenated rosin, and other chemically modified rosin), and various rosin derivatives.

As said rosin derivative, for example,

Rosin phenolic resin obtained by adding phenol to rosin (unmodified rosin, modified rosin, various rosin derivatives, etc.) with an acid catalyst and thermally polymerizing it;

An ester compound of rosin obtained by esterifying unmodified rosin with alcohol (unmodified rosin ester), or modified rosin such as polymerized rosin, stabilized rosin, disproportionated rosin, fully hydrogenated rosin, or partially hydrogenated rosin, to alcohol. rosin ester-based resins such as modified rosin ester compounds (polymerized rosin esters, stabilized rosin esters, disproportionated rosin esters, fully hydrogenated rosin esters, partially hydrogenated rosin esters, etc.);

unsaturated fatty acid-modified rosin-based resins obtained by modifying unmodified rosin or modified rosin (polymerized rosin, stabilized rosin, disproportionated rosin, fully hydrogenated rosin, partially hydrogenated rosin, etc.) with unsaturated fatty acids;

an unsaturated fatty acid-modified rosin ester-based resin obtained by modifying a rosin ester-based resin with an unsaturated fatty acid;

Reduction treatment of carboxyl groups in unmodified rosin, modified rosin (polymerized rosin, stabilized rosin, disproportionated rosin, fully hydrogenated rosin, partially hydrogenated rosin, etc.), unsaturated fatty acid-modified rosin-based resin or unsaturated fatty acid-modified rosin ester-based resin one rosin alcohol-based resin;

and metal salts of rosin-based resins (especially rosin ester-based resins) such as unmodified rosin, modified rosin, and various rosin derivatives.

Examples of the terpene-based tackifying resin include terpene-based resins such as α-pinene polymer, β-pinene polymer, and dipentene polymer, and modifications of these terpene-based resins (phenol modification, aromatic modification, hydrogenation modification, hydrocarbon modification, etc.) ) modified terpene-based resins (eg, terpene phenol-based resins, styrene-modified terpene-based resins, aromatic modified terpene-based resins, hydrogenated terpene-based resins, etc.);

As the phenol-based tackifying resin, for example, a condensate of various phenols (eg, phenol, m-cresol, 3,5-xylenol, p-alkylphenol, resorcin, etc.) and formaldehyde (eg, , alkylphenol-based resins, xyleneformaldehyde-based resins, etc.), resols obtained by addition reaction of the above phenols and formaldehyde with an alkali catalyst, and novolacs obtained by condensation reaction of the above-mentioned phenols with formaldehyde with an acid catalyst.

Examples of the hydrocarbon tackifying resin include an aliphatic hydrocarbon resin, an aromatic hydrocarbon resin, an aliphatic cyclic hydrocarbon resin, an aliphatic/aromatic petroleum resin (such as a styrene-olefin copolymer), an aliphatic/alicyclic petroleum resin, and a hydrogenated hydrocarbon. Various hydrocarbon-type resins, such as resin, a coumarone-type resin, and a coumarone indene-type resin, are mentioned.

Commercially available polymeric rosin esters that can be preferably used include Arakawa Chemical Co., Ltd. trade names "Pencel D-125", "Pencel D-135", "Pencel D-160", "Pencel KK", "Pencel" C" etc. are illustrated, but it is not limited to these.

Examples of commercially available terpene phenolic resins that can be preferably used include "YS Polystar S-145", "YS Polystar G-125", "YS Polystar N125", and "YS Poly" manufactured by Yasuhara Chemical. Star U-115", Arakawa Chemical Co., Ltd. brand name "Tamanol 803L", "Tamanol 901", Sumitomo Bakelite Co., Ltd. brand name "Sumilite Resin PR-12603" etc. are exemplified, It is not limited to these.

Content of tackifying resin is not specifically limited, According to the objective and a use, it can set so that appropriate adhesion performance may be exhibited. Content of tackifying resin with respect to 100 weight part of polymer A (when 2 or more types of tackifying resin is included, those total amounts) can be made into about 5-500 weight part, for example.

As tackifying resin, the thing with a softening point (softening temperature) of about 80 degreeC or more (preferably about 100 degreeC or more, for example, about 120 degreeC or more) can be used preferably. According to tackifying resin which has a softening point more than the lower limit mentioned above, the adhesive sheet which has high adhesive force after a heating is easy to be obtained. The upper limit of the softening point is not particularly limited, and may be, for example, approximately 200° C. or less (typically 180° C. or less). In addition, the softening point of tackifying resin can be measured based on the softening point test method (round-ball method) prescribed|regulated to JISK2207.

In addition, the pressure-sensitive adhesive layer in the technology disclosed herein is a leveling agent, a plasticizer, a softening agent, a colorant (dye, pigment, etc.), a filler, an antistatic agent, an anti-aging agent, within the range in which the effect of the present invention is not significantly hindered. , UV absorbers, antioxidants, light stabilizers, preservatives, and other known additives that can be used in the pressure-sensitive adhesive may be included as needed.

The pressure-sensitive adhesive layer constituting the pressure-sensitive adhesive sheet disclosed herein may be a cured layer of the pressure-sensitive adhesive composition. That is, the pressure-sensitive adhesive layer may be formed by applying (eg, applying) an adhesive composition such as a water dispersion type, a solvent type, a photocuring type, or a hot melt type to an appropriate surface, and then appropriately performing a curing treatment. When two or more curing treatments (drying, crosslinking, polymerization, cooling, etc.) are performed, these can be performed simultaneously or in multiple steps. In the pressure-sensitive adhesive composition using the partial polymer (polymer syrup) of the monomer raw material, a final copolymerization reaction is typically performed as the curing treatment described above. That is, the partial polymerization product is subjected to further copolymerization reaction to form a complete polymerization product. For example, if it is a photocurable adhesive composition, light irradiation is performed. If necessary, curing treatment such as crosslinking and drying may be performed. For example, when it is necessary to dry with a photocurable adhesive composition, what is necessary is just to photocurate after drying. In the pressure-sensitive adhesive composition using a completely polymerized product, typically, as the curing treatment, drying (heat drying), crosslinking, or the like is performed as needed.

Application|coating of an adhesive composition can be performed using conventional coaters, such as a gravure roll coater, a reverse roll coater, a kiss roll coater, a dip roll coater, a bar coater, a knife coater, and a spray coater, for example.

The thickness of an adhesive layer is not specifically limited, For example, it can be 1 micrometer or more. In some aspects, the thickness of the pressure-sensitive adhesive layer may be, for example, 3 µm or more, 5 µm or more, 8 µm or more, 10 µm or more, 15 µm or more, 20 µm or more, or 20 µm or more. may be in excess. There exists a tendency for adhesive force to rise after heating by increase in the thickness of an adhesive layer. Further, in some embodiments, the thickness of the pressure-sensitive adhesive layer may be, for example, 300 µm or less, 200 µm or less, 150 µm or less, 100 µm or less, 70 µm or less, or 50 µm or less. and may be 40 µm or less. The fact that the thickness of the pressure-sensitive adhesive layer is not too large may be advantageous from the viewpoint of reducing the thickness of the pressure-sensitive adhesive sheet or preventing cohesive failure of the pressure-sensitive adhesive layer. In addition, in the case of a pressure-sensitive adhesive sheet having a first pressure-sensitive adhesive layer and a second pressure-sensitive adhesive layer on the first and second surfaces of the substrate, the above-described thickness of the pressure-sensitive adhesive layer may be applied to at least the thickness of the first pressure-sensitive adhesive layer. The thickness of the second pressure-sensitive adhesive layer may also be selected within the same range. In addition, in the case of a non-substrate adhesive sheet, the thickness of the said adhesive sheet matches the thickness of an adhesive layer.

Storage elastic modulus G' (150 degreeC) in 150 degreeC of an adhesive layer is set suitably in the range which adhesive force rises more than predetermined value after mild heating, and is not limited to a specific range. In some embodiments, the storage elastic modulus G' (150° C.) of the pressure-sensitive adhesive layer may be 5000 Pa or more, and from the viewpoint of obtaining good adhesive properties such as low adhesion at the initial stage of pasting, preferably 10,000 Pa or more, more preferably It is 15,000 Pa or more, More preferably, it is 20,000 Pa or more (for example, 25,000 Pa or more), 30,000 Pa or more may be sufficient, 40,000 Pa or more may be sufficient, and 50,000 Pa or more may be sufficient. Moreover, the said storage elastic modulus G' (150 degreeC) may be 300,000 Pa or less, for example, may be 200,000 Pa or less, may be 150,000 Pa or less, and may be 100,000 Pa or less. In some preferred embodiments, the storage modulus G' (150° C.) is 90,000 Pa or less from the viewpoint of appropriately increasing the adhesive force after mild heating as a degree of crosslinking that can allow moderate movement of the polymer B in the pressure-sensitive adhesive layer, 70,000 Pa or less may be sufficient, 50,000 Pa or less may be sufficient, 40,000 Pa or less may be sufficient, and 30,000 Pa or less may be sufficient. The storage elastic modulus G' (150° C.) of the pressure-sensitive adhesive layer can be adjusted by the type and amount of the crosslinking agent, the molecular weight of the polymer A, the molecular structure, and the like. The storage modulus G' (150° C.) of the pressure-sensitive adhesive layer is measured by the method described in Examples to be described later.

Although it does not specifically limit, It is suitable that the gel fraction of the adhesive which comprises an adhesive layer normally exists in the range of 20.0% - 99.0%, and it is preferable to exist in the range of 30.0% - 90.0%. By making a gel fraction into the said range, the adhesive force increase after mild heating can be implement|achieved suitably. The gel fraction is measured by the following method.

[Measurement of gel fraction]

About 0.1 g of a pressure-sensitive adhesive sample (weight Wg ₁ ) is wrapped in a bag shape with a porous polytetrafluoroethylene membrane (weight Wg ₂ ) having an average pore diameter of 0.2 µm, and the mouth is tied _{with twisted yarn (weight Wg 3 ).} As the porous polytetrafluoroethylene membrane, trade name "Nitoflon (registered trademark) NTF1122" (Nitto Denko Co., Ltd., average pore diameter 0.2 µm, porosity 75%, thickness 85 µm) or an equivalent thereof is used. The package is immersed in 50 mL of ethyl acetate and maintained at room temperature (typically 23° C.) for 7 days to elute the sol powder (ethyl acetate soluble content) in the pressure-sensitive adhesive out of the membrane. Next, the package is taken out, ethyl acetate adhering to the outer surface is wiped off, the package is dried at 130° C. for 2 hours, and the weight (Wg ₄ ) of the package is measured. By substituting each value into the following formula|equation, gel fraction G _C of an adhesive is computable.

Gel fraction G _C (%)=[(Wg ₄ -Wg ₂ -Wg ₃ )/Wg ₁ ]×100

<Support description>

The pressure-sensitive adhesive sheet according to some embodiments may be in the form of a pressure-sensitive adhesive sheet provided with a substrate having pressure-sensitive adhesive layers on one side or both sides of a supporting substrate. The material of the supporting base material is not particularly limited, and can be appropriately selected depending on the purpose of use of the pressure-sensitive adhesive sheet, the mode of use, and the like. Non-limiting examples of the base material that can be used include a polyolefin film mainly composed of polyolefin such as polypropylene or ethylene-propylene copolymer, a polyester film composed mainly of polyester such as polyethylene terephthalate and polybutylene terephthalate, and poly Plastic films, such as a polyvinyl chloride film which has vinyl chloride as a main component; foam sheets including foams such as polyurethane foam, polyethylene foam, and polychloroprene foam; Woven and nonwoven fabrics made of various fibrous materials (which may be natural fibers such as hemp and cotton, synthetic fibers such as polyester and vinylon, and semi-synthetic fibers such as acetate) alone or mixed; papers such as Japanese paper, fine paper, kraft paper, and crepe paper; metal foils such as aluminum foil and copper foil; and the like. The description of the structure in which these were combined may be sufficient. Examples of such a composite substrate include, for example, a substrate having a structure in which a metal foil and the plastic film are laminated, and a plastic substrate reinforced with inorganic fibers such as glass cloth.

As a base material of the adhesive sheet disclosed herein, various film base materials can be used preferably. The film substrate may be a porous substrate, such as a foam film or a nonwoven fabric sheet, or a non-porous substrate, or a substrate having a structure in which a porous layer and a non-porous layer are laminated. In some embodiments, as the film substrate, an independently capable (self-supporting or non-dependent) resin film containing a resin film as the base film can be preferably used. Here, a "resin film" has a non-porous structure and typically means a resin film substantially free of air bubbles (voidless). Therefore, the said resin film is a concept distinguished from a foam film and a nonwoven fabric. As said resin film, the thing which can maintain a shape independently (a self-supporting type or non-dependent) can be used preferably. A single-layer structure may be sufficient as the said resin film, and the multilayer structure (for example, three-layer structure) of two or more layers may be sufficient as it.

Examples of the resin material constituting the resin film include polyamide (PA), polyimide (PI), polyamideimide (PAI), polyether such as polyester, polyolefin, nylon 6, nylon 66, and partially aromatic polyamide. Ether ketone (PEEK), polyether sulfone (PES), polyphenylene sulfide (PPS), polycarbonate (PC), polyurethane (PU), ethylene-vinyl acetate copolymer (EVA), polytetrafluoroethylene Resins, such as a fluororesin, such as (PTFE), an acrylic resin, polyacrylate, polystyrene, polyvinyl chloride, and polyvinylidene chloride, can be used. The said resin film may be formed using the resin material containing 1 type of such resin individually, and may be formed using the resin material in which 2 or more types were blended. Unstretched may be sufficient as the said resin film, and the thing extended|stretched (for example, uniaxial stretching or biaxial stretching) may be sufficient as it.

Suitable examples of the resin material constituting the resin film include polyester-based resins, PPS resins, and polyolefin-based resins. Here, polyester-type resin means resin which contains polyester in the ratio of more than 50 weight%. Similarly, the PPS resin refers to a resin containing PPS in a proportion exceeding 50% by weight, and the polyolefin-based resin refers to a resin containing a polyolefin in a proportion exceeding 50% by weight.

As the polyester-based resin, typically, a polyester-based resin containing, as a main component, a polyester obtained by polycondensing a dicarboxylic acid and a diol is used.

As dicarboxylic acid constituting the polyester, for example, phthalic acid, isophthalic acid, terephthalic acid, 2-methylterephthalic acid, 5-sulfoisophthalic acid, 4,4'-diphenyldicarboxylic acid, 4,4' -diphenyletherdicarboxylic acid, 4,4'-diphenylketonedicarboxylic acid, 4,4'-diphenoxyethanedicarboxylic acid, 4,4'-diphenylsulfonedicarboxylic acid, 1 aromatic dicarboxylic acids such as ,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and 2,7-naphthalenedicarboxylic acid; alicyclic dicarboxylic acids such as 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid; aliphatic dicarboxylic acids such as malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid and dodecanoic acid; unsaturated dicarboxylic acids such as maleic acid, maleic anhydride, and fumaric acid; derivatives thereof (eg, lower alkyl esters of the above dicarboxylic acids such as terephthalic acid); and the like. These can be used individually by 1 type or in combination of 2 or more type. An aromatic dicarboxylic acid is preferable from a viewpoint of intensity|strength etc. Among these, terephthalic acid and 2,6-naphthalenedicarboxylic acid are mentioned as dicarboxylic acid preferable. For example, 50% by weight or more (for example, 80% by weight or more, typically 95% by weight or more) of the dicarboxylic acids constituting the polyester is terephthalic acid, 2,6-naphthalenedicarboxylic acid or these It is preferable that it is a combination of The dicarboxylic acid may consist substantially only of terephthalic acid, substantially only of 2,6-naphthalenedicarboxylic acid, or substantially only of terephthalic acid and 2,6-naphthalenedicarboxylic acid.

Examples of the diol constituting the polyester include ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, 1,3-propanediol, 1,5-pentanediol, neopentyl glycol, 1,4 -aliphatic diols such as butanediol, 1,6-hexanediol, 1,8-octanediol, and polyoxytetramethylene glycol; Alicyclic diols such as 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,1-cyclohexanedimethylol, and 1,4-cyclohexanedimethylol, xylylene glycol, 4,4'-diol aromatic diols such as hydroxybiphenyl, 2,2-bis(4'-hydroxyphenyl)propane, and bis(4-hydroxyphenyl)sulfone; and the like. These can be used individually by 1 type or in combination of 2 or more type. Among them, aliphatic diols are preferable from the viewpoint of transparency and the like, and ethylene glycol is particularly preferable. It is preferable that the ratio of the aliphatic diol (preferably ethylene glycol) to the diol which comprises the said polyester is 50 weight% or more (for example, 80 weight% or more, typically 95 weight% or more). The said diol may be comprised substantially only from ethylene glycol.

Specific examples of the polyester resin include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), and polybutylene naphthalate.

As polyolefin resin, 1 type of polyolefin can be used individually or in combination of 2 or more types of polyolefins. The polyolefin may be, for example, an α-olefin homopolymer, a copolymer of two or more α-olefins, or a copolymer of one or two or more α-olefins with other vinyl monomers. Specific examples include ethylene-propylene copolymers such as polyethylene (PE), polypropylene (PP), poly-1-butene, poly-4-methyl-1-pentene, and ethylene propylene rubber (EPR), and ethylene-propylene-butene copolymers. a copolymer, an ethylene-butene copolymer, an ethylene-vinyl alcohol copolymer, an ethylene-ethyl acrylate copolymer, etc. are mentioned. Both low density (LD) polyolefins and high density (HD) polyolefins can be used. Examples of the polyolefin resin film include an unstretched polypropylene (CPP) film, a biaxially stretched polypropylene (OPP) film, a low density polyethylene (LDPE) film, a linear low density polyethylene (LLDPE) film, a medium density polyethylene (MDPE) film, a high density A polyethylene (HDPE) film, a polyethylene (PE) film in which two or more types of polyethylene (PE) are blended, a PP/PE blend film in which a polypropylene (PP) is blended with a polyethylene (PE), etc. are mentioned.

A PET film, a PEN film, a PPS film, a PEEK film, a CPP film, and an OPP film are mentioned as a specific example of the resin film preferably used as a base film of the adhesive sheet disclosed herein. A PET film, a PEN film, a PPS film, and a PEEK film are mentioned as an example of a preferable base film from a viewpoint of strength or dimensional stability. From viewpoints, such as the availability of a base material, a PET film and a PPS film are especially preferable, and a PET film is especially preferable.

In the resin film, in the range in which the effects of the present invention are not significantly hindered, known additives such as light stabilizers, antioxidants, antistatic agents, colorants (dyes, pigments, etc.), fillers, slip agents, and anti-blocking agents are required. can be combined according to The compounding quantity of an additive is not specifically limited, According to the use of an adhesive sheet, etc., it can set suitably.

The manufacturing method of a resin film is not specifically limited. For example, conventionally well-known general resin film molding methods, such as extrusion molding, inflation molding, T-die cast molding, and calender roll molding, can be employ|adopted suitably.

The substrate may be substantially composed of such a base film. Alternatively, the substrate may include an auxiliary layer in addition to the base film. Examples of the auxiliary layer include an optical property adjusting layer (eg, a colored layer, an antireflection layer), a printed layer or laminate layer for imparting a desired appearance to the substrate, a surface treatment layer such as an antistatic layer, an undercoat layer, and a release layer. can be heard

The thickness of the base material is not particularly limited, and can be selected according to the purpose of use of the pressure-sensitive adhesive sheet, the mode of use, and the like. The thickness of the substrate may be, for example, 1000 μm or less. In some aspects, from the viewpoint of handleability and workability of the pressure-sensitive adhesive sheet, the thickness of the substrate may be, for example, 500 µm or less, 300 µm or less, 250 µm or less, or 200 µm or less. From the viewpoint of size reduction or weight reduction of the product to which the pressure-sensitive adhesive sheet is applied, in some embodiments, the thickness of the substrate may be, for example, 160 µm or less, 130 µm or less, 100 µm or less, or 90 µm or less. , 80 µm or less, 60 µm or less, 50 µm or less, 25 µm or less, 10 µm or less, or 5 µm or less may be sufficient. When the thickness of a base material becomes small, there exists a tendency for the flexibility of an adhesive sheet and the followability|trackability with respect to the surface shape of a to-be-adhered body to improve. In addition, from the viewpoint of handleability and workability, the thickness of the substrate may be, for example, 2 µm or more, 5 µm or more, 10 µm or more, 20 µm or more, 25 µm or more, or more than 25 µm. may be In some embodiments, the thickness of the substrate may be, for example, 30 µm or more, 35 µm or more, 55 µm or more, 70 µm or more, 75 µm or more, 90 µm or more, 120 µm or more, It may be more than micrometer. For example, in a pressure-sensitive adhesive sheet that can be used for the purpose of reinforcing, supporting, and cushioning an adherend, a substrate having a thickness of 30 µm or more can be preferably employed.

On the first surface of the substrate, if necessary, a conventionally known surface treatment such as corona discharge treatment, plasma treatment, ultraviolet irradiation treatment, acid treatment, alkali treatment, formation of an undercoat layer by application of a primer (primer), etc. may be carried out. Such surface treatment may be a treatment for improving anchoring properties of the pressure-sensitive adhesive layer to the substrate. For example, the adhesive sheet provided with the base material which contains a resin film as a base film WHEREIN: The base material to which this anchoring property improvement process was given can be employ|adopted preferably. The said surface treatment can be applied individually or in combination. The composition of the primer used for formation of an undercoat layer is not specifically limited, It can select suitably from a well-known thing. The thickness of the undercoating layer is not particularly limited, but is usually about 0.01 μm to 1 μm, and preferably about 0.1 μm to 1 μm. Other treatments that may be applied to the first surface of the substrate as needed include antistatic layer forming treatment, colored layer forming treatment, printing treatment and the like.

When the pressure-sensitive adhesive sheet disclosed herein is in the form of a single-sided pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer only on the first surface of the substrate, the second surface of the substrate is subjected to a conventionally known surface treatment such as peeling treatment or antistatic treatment, if necessary. may be carried out. For example, by surface-treating the back surface of a base material with a peeling agent (typically by forming a peeling layer by a peeling agent), the rewinding force of the adhesive sheet of the form wound in roll shape can be made light. As the peeling agent, a silicone-based peeling agent, a long-chain alkyl-based peeling agent, an olefin-based peeling agent, a fluorine-based peeling agent, a fatty acid amide-based peeling agent, molybdenum sulfide, silica powder, or the like can be used. In addition, for the purpose of improving printability, reducing light reflectivity, and improving laminating properties, the second surface of the substrate may be subjected to a treatment such as corona discharge treatment, plasma treatment, ultraviolet irradiation treatment, acid treatment, alkali treatment, or the like. In the case of a double-sided pressure-sensitive adhesive sheet, the second surface of the substrate may be subjected to the same surface treatment as exemplified above as a surface treatment that can be applied to the first surface of the substrate, if necessary. In addition, the surface treatment performed on the 1st surface of a base material, and the surface treatment performed on the 2nd surface may be same or different.

<Adhesive sheet>

(Characteristics of the adhesive sheet, etc.)

The pressure-sensitive adhesive sheet disclosed herein _{may exhibit an adhesive force N 50 of} 5N/25 mm or more, that is, an adhesive force measured at 23° C. after bonding to a stainless steel plate and maintaining at 50° C. for 15 minutes. After the adhesive sheet which satisfies this characteristic is affixed to a to-be-adhered body, the adhesive force rises to more than a predetermined value by mild heating at about 50 degreeC. According to the technique disclosed herein, since it is possible to obtain a strong adhesive force by mild heating, the adhesive force N ₅₀ can be 7N/25mm or more, for example, 10N/25mm or more, and further 13N/25mm or more. , 15N/25mm or more, 17N/25mm or more, 19N/25mm or more, 21N/25mm or more, 23N/25mm or more (for example, 25N/25mm or more). The upper limit of the adhesive force N _{50 is not particularly limited.} From the viewpoint of the ease of manufacture and economical efficiency of the pressure-sensitive adhesive sheet, in some aspects, the adhesive force N ₅₀ may be, for example, 70 N/25 mm or less, 50 N/25 mm or less, or 40 N/25 mm or less.

_{Adhesive force N 23} measured after bonding to a stainless steel sheet and holding at 23° C. for 30 minutes is not particularly limited, and in some embodiments, the adhesive force N ₂₃ may be, for example, 3 N/25 mm or less, preferably 2.5N/25mm or less, More preferably, it is less than 2N/25mm, 1.5N/25mm or less may be sufficient, 1.2N/25mm or less may be sufficient, and 1N/25mm or less may be sufficient. The adhesive strength ₂₃ N is low, it is preferable in view Rework resistance. The lower limit in particular of adhesive force N ₂₃ is not restrict|limited, For example. It may be 0.01N/25mm or more. From viewpoints of sticking workability to an adherend, prevention of position shift before an adhesive force rise, etc., _{it is suitable that adhesive force N 23} is 0.1 N/25 mm or more normally. From the viewpoint of improving the adhesive force after heating, etc., in some embodiments, the adhesive force N ₂₃ may be, for example, 0.2 N/25 mm or more, 0.5 N/25 mm or more, or 0.8 N/25 mm or more, 1.0 N/25 mm or more (for example, 1.5 N/25 mm or more) may be sufficient.

_{Adhesive force N 80} measured at 23 ° C after bonding to a stainless steel plate and holding at 80 ° C for 5 minutes is not particularly limited, and in some embodiments, the adhesion force N ₈₀ may be, for example, 5 N/25 mm or more, 7N/25mm or more, 10N/25mm or more, 13N/25mm or more, 15N/25mm or more, 17N/25mm or more, 20N/25mm or more, may be sufficient, and 25N/25mm or more may be sufficient. 25 mm or more may be sufficient, and 30 N/25 mm or more (for example, 35 N/25 mm or more) may be sufficient. In addition, from the viewpoint of the ease of manufacture and economical efficiency of the pressure-sensitive adhesive sheet, in some aspects, the adhesive force N ₈₀ may be, for example, 70 N/25 mm or less, 50 N/25 mm or less, or 40 N/25 mm or less.

The ratio of the adhesive force N ₅₀ [N/25 mm] to the adhesive force N ₂₃ [N/25 mm], that is, the adhesive force rise ratio N ₅₀ /N ₂₃ is not particularly limited, and in some embodiments, N ₅₀ /N ₂₃ It is suitable that it is 2 or more (for example, 3 or more), preferably 5 or more, more preferably 8 or more, 10 or more, 12 or more, 15 or more, 18 or more, 20 or more may be sufficient. N ₅₀ / N ₂₃ is large, according to the pressure-sensitive adhesive sheet, patch initially show a good Rework property, and can greatly increase the adhesive strength by the subsequent heating. The upper limit of N ₅₀ /N ₂₃ is not particularly limited, and is usually 100 or less, 80 or less, 60 or less, or 50 or less, and from the viewpoint of ease of manufacture and economical efficiency of the pressure-sensitive adhesive sheet, typically It is 30 or less, and 20 or less may be sufficient. In some aspects, N ₅₀ /N ₂₃ may be, for example, 18 or less, 15 or less, or 12 or less.

The ratio of the adhesive force N ₈₀ [N/25 mm] to the adhesive force N ₅₀ [N/25 mm], that is, the adhesive force rise ratio N ₈₀ /N ₅₀ is not particularly limited, and in some embodiments, N ₈₀ /N ₅₀ It is suitable that silver is 3 or less, Preferably it is 2 or less, for example, 1.8 or less may be sufficient, and 1.5 or less (for example, 1.3 or less) may be sufficient. According to the pressure-sensitive adhesive sheet satisfying this characteristic, the adhesive strength can be sufficiently increased by mild heating at about 50°C, and there is no need to expose it to a further high temperature (specifically, heating at about 80°C) in order to obtain the desired adhesive strength. . The lower limit of N ₈₀ /N ₅₀ is not particularly limited, and from the viewpoint of ease of manufacture and economical efficiency of the pressure-sensitive adhesive sheet, in some embodiments, for example, may be 1 or more, 1.2 or more, 1.4 or more, or 1.6 or more. may be

Here, the adhesive force N ₂₃ [N/25 mm] is pressure-bonded to a stainless steel (SUS) plate as an adherend and left for 30 minutes in an environment of 23°C and 50%RH, and then in the same environment (that is, at 23°C). ), a peel angle of 180 degrees, and a tensile rate of 300 mm/min are determined by measuring the peel adhesive force of 180 degrees.

Adhesive force N ₅₀ [N/25 mm] is pressed against a SUS plate as an adherend, held in an environment of 50° C. for 15 minutes, and then left in an environment of 23° C. and 50% RH for 30 minutes, then in the same environment , is grasped by measuring the peeling adhesive force of 180° under the conditions of a peel angle of 180 degrees and a tensile rate of 300 mm/min.

Adhesive force N ₈₀ [N/25 mm] is pressed against a SUS plate as an adherend, heated at 80° C. for 5 minutes, and then left in an environment of 23° C. and 50% RH for 30 minutes, followed by peeling in the same environment. It is grasped|ascertained by measuring 180 degree peel adhesive force under the conditions of an angle 180 degree and a tensile speed of 300 mm/min.

As the adherend, In any measurement of the adhesive force _{N 23, N 50, N 80} , is used SUS304BA plate. In a measurement, an appropriate backing material (for example, PET film with a thickness of about 25 micrometers) can be affixed and reinforced on the adhesive sheet of a measurement object as needed. Adhesive force N ₂₃ , N ₅₀ , N ₈₀ can be measured according to the method described in the Example which will be mentioned later more specifically,.

In addition, the adhesive force after heating of the adhesive sheet disclosed here shows one characteristic of this adhesive sheet, and does not limit the usage aspect of this adhesive sheet. In other words, the usage aspect of the adhesive sheet disclosed here is not limited to the aspect which performs heating for 15 minutes at 50 degreeC, For example, a room temperature range (usually 20 degreeC - 30 degreeC, typically 23 degreeC) to 25° C.) or higher, it can be used even in an embodiment in which no treatment is particularly performed. Also in such a usage mode, adhesive force rises in a long term, and strong bonding can be implement|achieved. Moreover, the raise of adhesive force can be accelerated|stimulated by heat-processing the adhesive sheet disclosed here at the temperature higher than 30 degreeC (for example, 50 degreeC) or 50 degreeC at arbitrary timings after sticking. The heating temperature in such heat treatment is not particularly limited, and can be set in consideration of workability, economy, heat resistance of the base material of the pressure-sensitive adhesive sheet, the adherend, and the like. The heating temperature may be, for example, less than 150°C, 120°C or less, 100°C or less, 80°C or less, and 70°C or less. The heating temperature may be, for example, 40°C or higher, 45°C or higher, 50°C or higher, 55°C or higher, 60°C or higher, or 70°C or higher, may be 80°C or higher, or 100°C or higher. You can do it. Heating time is not specifically limited, For example, 1 hour or less may be sufficient, 30 minutes or less may be sufficient, 10 minutes or less may be sufficient, and 5 minutes or less may be sufficient. Further, the heating time may be, for example, 1 minute or longer, 3 minutes or longer, 7 minutes or longer, or 15 minutes or longer. Alternatively, as long as no significant thermal deterioration occurs in the pressure-sensitive adhesive sheet or the adherend, heat treatment for a longer period of time may be performed. In addition, heat processing may be performed at once, and may be divided into multiple times and may be performed.

(Adhesive sheet with base material)

When the PSA sheet disclosed herein is in the form of an PSA sheet with a base material, the PSA sheet may have a thickness of, for example, 1000 µm or less, 600 µm or less, 350 µm or less, or 250 µm or less. From the viewpoint of miniaturization, weight reduction, thinning, etc. of the product to which the pressure-sensitive adhesive sheet is applied, in some embodiments, the thickness of the pressure-sensitive adhesive sheet may be, for example, 200 µm or less, 175 µm or less, 140 µm or less, 120 Micrometer or less may be sufficient and 100 micrometers or less (for example, less than 100 micrometers) may be sufficient. In addition, from a viewpoint of handleability, etc., the thickness of an adhesive sheet may be 5 micrometers or more, 10 micrometers or more, 15 micrometers or more, 20 micrometers or more, 25 micrometers or more, may be sufficient, for example from a viewpoint, for example. It may be more than Some aspects WHEREIN: The thickness of an adhesive sheet may be 50 micrometers or more, 60 micrometers or more may be sufficient, for example may be sufficient as 80 micrometers or more, 100 micrometers or more may be sufficient, and 120 micrometers or more may be sufficient as it. The upper limit of the thickness of an adhesive sheet is not specifically limited.

In addition, the thickness of an adhesive sheet means the thickness of the part affixed to a to-be-adhered body. For example, in the adhesive sheet 1 of the structure shown in FIG. 1, the thickness from the adhesive surface 21A of the adhesive sheet 1 to the 2nd surface 10B of the base material 10 is indicated, and the release liner 31 ) is not included.

The pressure-sensitive adhesive sheet disclosed herein can be suitably implemented, for example, in an aspect in which the thickness Ts of the supporting substrate is larger than the thickness Ta of the pressure-sensitive adhesive layer, that is, in an aspect in which Ts/Ta is larger than one. Although it does not specifically limit, For example, 1.1 or more may be sufficient as Ts/Ta, 1.2 or more may be sufficient, 1.5 or more may be sufficient, and 1.7 or more may be sufficient as Ts/Ta. For example, in a pressure-sensitive adhesive sheet that can be used for the purpose of reinforcing, supporting, and cushioning an adherend, an increase in Ts/Ta tends to make it easier to exhibit a favorable effect even when the pressure-sensitive adhesive sheet is reduced in thickness. In some aspects, Ts/Ta may be 2 or more (eg, greater than 2), may be 2.5 or more, and may be 2.8 or more. In addition, Ts/Ta may be 50 or less, for example, and 20 or less may be sufficient as it. From a viewpoint of making it easy to exhibit high post-heat adhesive force even if an adhesive sheet is made thin, for example, 10 or less may be sufficient, 8 or less may be sufficient, and 5 or less may be sufficient as Ts/Ta.

It is preferable that the said adhesive layer is being adhered to the support base material. Here, sticking means that, in the pressure-sensitive adhesive sheet having an increased adhesive strength after sticking to an adherend, the pressure-sensitive adhesive layer is a supporting substrate to such an extent that peeling at the interface between the pressure-sensitive adhesive layer and the supporting substrate does not occur when the pressure-sensitive adhesive sheet is peeled from the adherend. indicates sufficient anchoring properties for According to the adhesive sheet provided with the base material by which the adhesive layer is fixed to the support base material, a to-be-adhered body and a support base material can be integrated firmly. A preferred example of the pressure-sensitive adhesive sheet in which the pressure-sensitive adhesive layer is adhered to the substrate includes an adhesive sheet in which peeling (breaking of anchorage) does not occur between the pressure-sensitive adhesive layer and the supporting substrate when measuring the adhesive force after heating. A pressure-sensitive adhesive sheet having an adhesive strength of 15 N/25 mm or more after heating, and in which anchorage breakage does not occur during measurement of the adhesive strength after heating is a suitable example corresponding to a pressure-sensitive adhesive sheet in which the pressure-sensitive adhesive layer is adhered to the substrate.

The pressure-sensitive adhesive sheet disclosed herein is, for example, in a method comprising contacting a liquid pressure-sensitive adhesive composition to a first surface of a substrate, and curing the pressure-sensitive adhesive composition on the first surface to form a pressure-sensitive adhesive layer in this order. It can be preferably prepared by Curing of the pressure-sensitive adhesive composition may be accompanied by one or two or more of drying, crosslinking, polymerization, cooling, and the like of the pressure-sensitive adhesive composition. According to the method of forming the pressure-sensitive adhesive layer by curing the liquid pressure-sensitive adhesive composition on the first surface of the substrate as described above, by bonding the cured pressure-sensitive adhesive layer to the first surface of the substrate, the method of disposing the pressure-sensitive adhesive layer on the first surface On the other hand, anchoring property with respect to the base material of an adhesive layer can be improved. By using this, the adhesive sheet in which the adhesive layer adhered to the base material can be manufactured suitably.

In some embodiments, as a method of contacting the liquid pressure-sensitive adhesive composition to the first surface of the substrate, a method of directly applying the pressure-sensitive adhesive composition to the first surface of the substrate may be employed. By bringing the first surface (adhesive surface) of the pressure-sensitive adhesive layer cured on the first surface of the substrate into contact with the release surface, the second surface of the pressure-sensitive adhesive layer is fixed to the first surface of the substrate, and the first surface of the pressure-sensitive adhesive layer is adhered to the first surface of the substrate. The adhesive sheet of the structure in which the surface contact|connected the peeling surface can be obtained. As said release surface, the surface of a release liner, the back surface of the base material by which the release process was carried out, etc. can be used.

In addition, for example, in the case of a photo-curable pressure-sensitive adhesive composition using a partial polymer (polymer syrup) of a monomer raw material, for example, the pressure-sensitive adhesive composition is applied to the release surface, and then the first surface of the substrate is covered with the applied pressure-sensitive adhesive composition As a result, the pressure-sensitive adhesive layer may be formed by bringing the first surface of the substrate into contact with the uncured pressure-sensitive adhesive composition, and curing the pressure-sensitive adhesive composition sandwiched between the first surface and the release surface in that state by irradiating light.

In addition, the method illustrated above does not limit the manufacturing method of the adhesive sheet disclosed here. In the production of the pressure-sensitive adhesive sheet disclosed herein, an appropriate method capable of adhering the pressure-sensitive adhesive layer to the first surface of the substrate may be used alone or in combination of two or more thereof. Examples of such a method include a method of curing the liquid pressure-sensitive adhesive composition on the first surface of the substrate to form a pressure-sensitive adhesive layer as described above, or a method of subjecting the first surface of the substrate to surface treatment to improve anchoring properties of the pressure-sensitive adhesive layer. and the like. For example, when anchoring properties of the pressure-sensitive adhesive layer to the substrate can be sufficiently improved by a method such as forming an undercoating layer on the first surface of the substrate, the cured pressure-sensitive adhesive layer is bonded to the first surface of the substrate. You may manufacture an adhesive sheet by this method. Moreover, anchoring property with respect to the base material of an adhesive layer can be improved also by selection of the material of a base material, or selection of a composition of an adhesive. In addition, by applying a temperature higher than room temperature to the pressure-sensitive adhesive sheet having the pressure-sensitive adhesive layer on the first surface of the substrate, anchoring properties of the pressure-sensitive adhesive layer to the substrate can be improved. The temperature applied in order to improve anchoring property may be, for example, about 35 degreeC - about 80 degreeC, about 40 degreeC - about 70 degreeC may be sufficient, and about 45 degreeC - about 60 degreeC may be sufficient, for example.

The pressure-sensitive adhesive sheet disclosed herein is in the form of a pressure-sensitive adhesive sheet having a first pressure-sensitive adhesive layer provided on the first surface of a base material and a second pressure-sensitive adhesive layer provided on the second surface of the base material (ie, double-sided adhesive base material-equipped pressure-sensitive adhesive sheet) In the case of , the same structure may be sufficient as a 1st adhesive layer and a 2nd adhesive layer, and a different structure may be sufficient as them. When the configuration of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer are different, the difference may be, for example, a difference in composition or a difference in structure (thickness, surface roughness, formation range, formation pattern, etc.). For example, the adhesive layer which does not contain the polymer B may be sufficient as a 2nd adhesive layer. Further, the surface of the second adhesive layer (second adhesive surface), the adhesive strength N ₅₀ is 5N / 25㎜ be either less than 3N / 25㎜ be either less than, be either 1.5N / under 25㎜, 1N / under 25㎜ may be

<Adhesive sheet with release liner>

The pressure-sensitive adhesive sheet disclosed herein can take the form of a pressure-sensitive adhesive product in which the surface (adhesive surface) of the pressure-sensitive adhesive layer is brought into contact with the release surface of the release liner. Accordingly, by this specification, there can be provided an adhesive sheet (adhesive product) with a release liner comprising any of the pressure-sensitive adhesive sheets disclosed herein and a release liner having a release surface in contact with the pressure-sensitive adhesive surface of the pressure-sensitive adhesive sheet.

Although the thickness of a release liner is not specifically limited, Usually, about 5 micrometers - 200 micrometers is suitable. When the thickness of a release liner exists in the said range, since it is excellent in the bonding workability|operativity with respect to an adhesive layer, and peeling workability|operativity from an adhesive layer, it is preferable. In some aspects, the thickness of the release liner may be, for example, 10 µm or more, 20 µm or more, 30 µm or more, or 40 µm or more. In addition, from a viewpoint of facilitating peeling from an adhesive layer, the thickness of a release liner may be 100 micrometers or less, and may be 80 micrometers or less, for example. If necessary, the release liner may be subjected to a known antistatic treatment such as a coating type, a kneading type, and a vapor deposition type.

The release liner is not particularly limited, and for example, a release liner having a release layer on the surface of a liner substrate such as a resin film or paper (which may be a paper laminated with a resin such as polyethylene), or a fluorine-based polymer (poly A release liner comprising a resin film formed of a low-adhesive material such as tetrafluoroethylene or the like) or a polyolefin-based resin (polyethylene, polypropylene, etc.) can be used. From the viewpoint of excellent surface smoothness, a release liner having a release layer on the surface of a resin film as a liner substrate, or a release liner comprising a resin film formed of a low-adhesive material can be preferably employed. The resin film is not particularly limited as long as it is a film capable of protecting the pressure-sensitive adhesive layer, and for example, a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a polymethylpentene film, a polyvinyl chloride film, and a vinyl chloride film. A coal film, a polyester film (PET film, PBT film, etc.), a polyurethane film, an ethylene-vinyl acetate copolymer film, etc. are mentioned. In the formation of the release layer, for example, a silicone-based release agent, a long-chain alkyl-based release agent, an olefin-based release agent, a fluorine-based release agent, a fatty acid amide-based release agent, molybdenum sulfide, silica powder, and other known release agents can be used. have. Use of a silicone type peeling agent is especially preferable.

The thickness of the release layer is not particularly limited, but is usually about 0.01 µm to 1 µm, and preferably about 0.1 µm to 1 µm. The formation method of a peeling layer is not specifically limited, A well-known method according to the kind etc. of the peeling agent to be used can be employ|adopted suitably.

<Use>

The pressure-sensitive adhesive sheet provided by this specification can, for example, exhibit good reworkability in the initial stage of bonding to an adherend, thereby contributing to suppression of yield reduction and improvement of quality of products including the pressure-sensitive adhesive sheet. have. In addition, the adhesive sheet can greatly increase the adhesive strength by aging (which may be mild heating near 50° C., aging, a combination thereof, etc.). For example, by heating at a desired timing, the pressure-sensitive adhesive sheet can be firmly adhered to the adherend. Taking advantage of these characteristics, the pressure-sensitive adhesive sheet disclosed herein can be preferably used for the purpose of fixing, bonding, molding, decorating, protecting, reinforcing, supporting, shock mitigation, etc. of members included in various products in various fields. have.

The pressure-sensitive adhesive sheet disclosed herein is, for example, in the form of an adhesive sheet provided with a base material in which an pressure-sensitive adhesive layer is formed on at least a first surface of a film-like substrate having a first surface and a second surface, and is affixed to an adherend and adhered to the adherend. It can be preferably used as a reinforcing film for reinforcing the Such a reinforcing film WHEREIN: As said film base material, what contains a resin film as a base film can be used preferably. Moreover, it is preferable that the said adhesive layer is adhering to the 1st surface of a film-form base material from a viewpoint of improving reinforcement performance.

For example, in an optical member used for an optical product or an electronic member used for an electronic product, a high degree of integration, miniaturization, weight reduction, and thinning are progressing, and a plurality of thin optical members/electronic members having different coefficients of linear expansion and thickness are being produced. can be stacked. By affixing the above reinforcing films to such a member, moderate rigidity can be provided to the said optical member/electronic member. Thereby, in a manufacturing process and/or a product after manufacture, the curl and curvature resulting from the stress which may generate|occur|produce between the several members from which the said linear expansion coefficient and thickness differ can be suppressed.

Further, in the optical product / electronic product manufacturing process, in the situation where the thin optical member / electronic member is subjected to shape processing such as cutting processing as described above, by attaching a reinforcing film to the member and processing, The local stress concentration to the accompanying optical member/electronic member can be relieve|moderated, and risks, such as a crack, a crack, and peeling of a lamination|stacking member, can be reduced. Attaching the reinforcing member to the optical member/electronic member and handling it is also helpful in relieving local stress concentration during conveyance, lamination, rotation, etc. can be

In addition, when the device such as an optical product or an electronic product including the reinforcing film is used by consumers in the market, when the device falls, when placed under a heavy object, when a flying object collides, etc., Even when unintentional stress is applied, the stress applied to the device can be alleviated by including the reinforcing film in the device. Therefore, by including the reinforcing film in the device, durability of the device can be improved.

In addition, the adhesive sheet disclosed here can be used suitably in the aspect affixed to the member which comprises various portable devices (portable device), for example. Here, "portability" is considered to mean that it is not sufficient to simply be able to carry it, and has a level of portability that an individual (a standard adult) can carry relatively easily. In addition, examples of the portable device referred to herein include a mobile phone, a smartphone, a tablet-type personal computer, a notebook computer, various wearable devices, a digital camera, a digital video camera, an audio device (a portable music player, an IC recorder, etc.), a calculator (electronic type) desktop calculators), portable game devices, electronic dictionaries, electronic notebooks, electronic books, in-vehicle information devices, portable radios, portable TVs, portable printers, portable scanners, portable modems, etc., as well as mechanical watches and pockets. This may include a watch, a flashlight, a hand mirror, and the like. Examples of the member constituting the portable electronic device may include an optical film or a display panel used in an image display device such as a thin-layer display such as a liquid crystal display or a film-shaped display. The pressure-sensitive adhesive sheet disclosed herein can be preferably used also in an aspect affixed to various members in automobiles, household electrical appliances, and the like.

Example

Hereinafter, some examples related to the present invention will be described, but it is not intended to limit the present invention to those shown in these specific examples. In addition, unless otherwise specified, "part" and "%" in the following description are based on weight.

(Preparation of polymer A1)

In a reaction vessel equipped with a stirring blade, a thermometer, a nitrogen gas introduction tube and a cooler, 60 parts of 2-ethylhexyl acrylate (2EHA), 15 parts of N-vinyl-2-pyrrolidone (NVP), and methyl methacrylate ( 10 parts of MMA), 15 parts of 2-hydroxyethyl acrylate (HEA), and 200 parts of ethyl acetate as a polymerization solvent were added, stirred at 60° C. for 2 hours under a nitrogen atmosphere, and 2,2'- as a thermal polymerization initiator. 0.2 parts of azobisisobutyronitrile (AIBN) was thrown in, reaction was performed at 60 degreeC for 6 hours, and the solution of polymer A1 was obtained. The Mw of this polymer A1 was 1.1 million.

(Preparation of polymer B1)

In a reaction vessel equipped with a stirring blade, a thermometer, a nitrogen gas introduction tube and a cooler, 40 parts of MMA, 20 parts of n-butyl methacrylate (BMA), 20 parts of 2-ethylhexyl methacrylate (2EHMA), a functional group equivalent 8.7 parts of 900 g/mol polyorganosiloxane skeleton-containing methacrylate monomer (trade name: X-22-174ASX, manufactured by Shin-Etsu Chemical Co., Ltd.), polyorganosiloxane skeleton-containing methacrylic having a functional group equivalent of 4600 g/mol 11.3 parts of a late monomer (trade name: KF-2012, manufactured by Shin-Etsu Chemical Co., Ltd.), 100 parts of ethyl acetate, and 0.5 parts of thioglycerol as a chain transfer agent were added, stirred at 70 ° C. under a nitrogen atmosphere for 1 hour, and then heat 0.2 part of AIBN was thrown in as a polymerization initiator, and after making it react at 70 degreeC for 2 hours, 0.1 weight part of AIBN was thrown in as a thermal polymerization initiator, and it was made to react at 80 degreeC continuously for 5 hours. In this way, a solution of polymer B1 was obtained. The Mw of this polymer B1 was 2.2×10 ⁴ .

(Preparation of polymer B2)

Except for not using a thioglycerol in the same manner as the preparation of the polymer B1, the Mw was obtained a solution of 16.5 × 10 ⁴ of polymer B2.

In addition, the weight average molecular weight of each polymer mentioned above was measured on the following conditions using the GPC apparatus (made by Tosoh Corporation, HLC-8220GPC), and was calculated|required by polystyrene conversion.

[GPC conditions]

ㆍSample concentration: 0.2 wt% (tetrahydrofuran (THF) solution)

ㆍSample injection volume: 10μl

ㆍEluent: THF

ㆍFlow rate: 0.6ml/min

ㆍMeasurement temperature: 40℃

ㆍColumn:

sample column; TSKguardcolumn SuperHZ-H (1EA) + TSKgel SuperHZM-H (2EA)

reference column; TSKgel SuperH-RC (1 pc.)

ㆍDetector: Differential Refractometer (RI)

<Production of adhesive sheet>

(Example 1)

To the solution of polymer A1, 2 parts of polymer B1 and 0.5 parts of an isocyanate-based crosslinking agent (trade name: Takenate D110N, trimethylolpropane xylylene diisocyanate, manufactured by Mitsui Chemicals Co., Ltd.) per 100 parts of polymer A1 contained in the solution and uniformly mixed to prepare an adhesive composition C1.

The pressure-sensitive adhesive composition C1 is directly applied to the first surface of a 75 µm-thick polyethylene terephthalate (PET) film (manufactured by Toray Corporation, trade name “Lumiror”) as a supporting substrate, and dried by heating at 110° C. for 2 minutes to dry, 15 µm in thickness of the pressure-sensitive adhesive layer was formed. The release surface of the release liner was bonded to the surface (adhesive surface) of this pressure-sensitive adhesive layer. As the release liner, MRQ25T100 manufactured by Mitsubishi Chemical (a release liner having a release layer made of a silicone release treatment agent on one side of a polyester film, a thickness of 25 µm) was used. In this way, the PSA sheet according to Example 1 was obtained in the form of an PSA sheet with a release liner in which the release surface of the release liner was in contact with the pressure sensitive adhesive surface.

(Examples 2 to 4)

Except having changed the kind of polymer B or the usage-amount of a crosslinking agent as shown in Table 1, it carried out similarly to preparation of the adhesive composition C1, and prepared the adhesive compositions C2 - C4. In the same manner as in the preparation of the pressure-sensitive adhesive sheet according to Example 1, except that these pressure-sensitive adhesive compositions C2 to C4 were used, respectively, the pressure-sensitive adhesive sheets according to Examples 2 to 4 were prepared. obtained in the form of

<Storage modulus G' (150°C)>

The storage elastic modulus G' (150 degreeC) of the adhesive layer was calculated|required by the dynamic viscoelasticity measurement. Specifically, a pressure-sensitive adhesive layer having a thickness of about 2 mm was formed by forming a pressure-sensitive adhesive layer under basically the same conditions as in each example except that the pressure-sensitive adhesive layer was formed on the release surface of the release liner instead of the PET film, and a plurality of the pressure-sensitive adhesive layers were overlapped. was formed. A sample obtained by punching out the obtained pressure-sensitive adhesive layer into a disk shape with a diameter of 7.9 mm is sandwiched between parallel plates and fixed, and is dynamically performed under the following conditions by a viscoelasticity tester (for example, “ARES” manufactured by TA Instruments Co., Ltd. may be an equivalent product) The viscoelasticity measurement was performed and the storage modulus G' (150 degreeC) was calculated|required. In addition, you may form the adhesive layer which is a measurement object by apply|coating the corresponding adhesive composition layer by layer to the peeling surface of a peeling liner, etc., and drying or hardening it.

・Measurement mode: shear mode

·Temperature range: -50℃ to 200℃

·Temperature increase rate: 5℃/min

・Measurement frequency: 1Hz

<Measurement of adhesive force (23°C)>

Using the adhesive sheet according to each example cut to a width of 25 mm with the release liner as a test piece, using a SUS plate (SUS304BA plate) cleaned with toluene as an adherend _{, the adhesive force N 23} , the adhesive force N ₅₀ and the adhesive force N in the following procedure ₈₀ was measured.

(Measurement of adhesive force N ₂₃₎

In a standard environment of 23°C and 50%RH, the release liner covering the adhesive surface of each test piece was peeled off, and the exposed adhesive surface was pressed against the adherend by one reciprocating 2 kg roller. After leaving the test piece crimped to the adherend in this way for 30 minutes under the standard environment, it was peeled off in accordance with JIS Z0237 using a universal tensile and compression tester (device name "Tensile Compression Tester, TCM-1kNB" manufactured by Minebea). Under the conditions of an angle of 180 degrees and a tensile speed of 300 mm/min, 180 degrees peel adhesive force (resistance to the tension) was measured. The measurement was performed 3 times, and the average value thereof _{was shown in Table 1 as adhesive force N 23} [N/25 mm].

(Measurement of adhesive force N ₅₀₎

In the same manner as in the measurement of the adhesive force ₂₃ , the test piece press-bonded to the adherend was held in an environment of 50° C. for 15 minutes, and then left to stand in the standard environment for 30 minutes, and then the 180° peel adhesive force was similarly measured. The measurement was performed three times, and the average value thereof _{was shown in Table 1 as adhesive force N 50} [N/25 mm].

(Measurement of adhesive force N ₈₀₎

The test piece crimped to the adherend in the same manner as in the measurement of the adhesive force ₂₃ was heated at 80° C. for 5 minutes, and then left to stand for 30 minutes under the standard environment, and then the 180° peel adhesive force was similarly measured. The measurement was performed three times, and the average value thereof _{was shown in Table 1 as adhesive force N 80} [N/25 mm]. Further, the pressure-sensitive adhesive sheet according to Example 1-4, it was confirmed that all, does not indicate fracture anchored in the measurement of the adhesive strength ₈₀ N.

Based on these adhesive force measurement results, adhesive force increase ratio N ₈₀ /N ₅₀ and N ₅₀ /N ₂₃ were computed. The results are shown in Table 1.

As shown in Table 1, the pressure-sensitive adhesive sheets according to Examples 1 to 4 include a pressure-sensitive adhesive layer comprising a polymer A and a polymer B, which is a copolymer of a monomer having a polyorganosiloxane skeleton and a (meth)acrylic monomer. , all exhibited an _{adhesive force N 50} of 5N/25 mm or more. It turns out that these adhesive sheets can show favorable rework property in an affixing initial stage, and adhesive force can rise more than predetermined value by mild heating of about 50 degreeC after that. Moreover, especially favorable results were obtained in Examples 1-3 using the adhesive layer whose storage elastic modulus G' (150 degreeC) in 150 degreeC is 10,000 Pa or more and 90,000 Pa or less. Specifically, there can be further improved while suppressing the adhesiveness N ₅₀ N ₂₃ low adhesive force equivalent to, the initial patch.

As mentioned above, although the specific example of this invention was described in detail, these are only an illustration and do not limit a claim. The technology described in the claims includes various modifications and changes of the specific examples exemplified above.

1, 2, 3: Adhesive sheet
10: support substrate
10A: first side
10B: second side
21: adhesive layer (first adhesive layer)
21A: adhesive side (first adhesive side)
21B: adhesive side (second adhesive side)
22: adhesive layer (second adhesive layer)
22A: adhesive side (second adhesive side)
31, 32: release liner
100, 200, 300: adhesive sheet with release liner (adhesive product)

Claims (14)

It is an adhesive sheet comprising an adhesive layer,
The pressure-sensitive adhesive layer includes a polymer A and a polymer B, which is a copolymer of a monomer having a polyorganosiloxane skeleton and a (meth)acrylic monomer,
_{Adhesive force N 50} measured at 23° C. after bonding to a stainless steel sheet and maintaining at 50° C. for 15 minutes is 5 N/25 mm or more, the pressure-sensitive adhesive sheet. According to claim 1,
_{Adhesive force N 23} measured after bonding to a stainless steel sheet and holding at 23° C. for 30 minutes is 3 N/25 mm or less, the pressure-sensitive adhesive sheet. 3. The method of claim 1 or 2,
The adhesive force N _{50 is 5 times or more of the adhesive force N 23} measured after bonding to a stainless steel sheet and maintaining at 23° C. for 30 minutes, the pressure-sensitive adhesive sheet. 4. The method according to any one of claims 1 to 3,
_{Adhesive force N 80} measured at 23 ° C. after bonding to a stainless steel sheet and maintaining at 80 ° C. for 5 minutes is 2 times or less of the adhesive force N ₅₀ , the pressure-sensitive adhesive sheet. 5. The method according to any one of claims 1 to 4,
The storage elastic modulus G' (150° C.) of the pressure-sensitive adhesive layer at 150° C. is 10,000 Pa or more and 90,000 Pa or less, the pressure-sensitive adhesive sheet. 6. The method according to any one of claims 1 to 5,
The polymer A included in the pressure-sensitive adhesive layer is chemically cross-linked, the pressure-sensitive adhesive sheet. 7. The method according to any one of claims 1 to 6,
The weight average molecular weight of the said polymer B is 100,000 or more, the adhesive sheet. 7. The method according to any one of claims 1 to 6,
The weight average molecular weight of the polymer B is less than 80,000, the adhesive sheet. 9. The method according to any one of claims 1 to 8,
The adhesive sheet whose content of the said polymer B in the said adhesive layer is 0.5 weight part or more and 50 weight part or less with respect to 100 weight part of said polymer A. 10. The method according to any one of claims 1 to 9,
The polymer A is an acrylic polymer, the pressure-sensitive adhesive sheet. 11. The method of claim 10,
The said acrylic polymer contains the monomer which has a nitrogen atom containing ring as its monomer unit, The adhesive sheet. 12. The method according to any one of claims 1 to 11,
The monomer component for preparing the said polymer B, as said (meth)acrylic-type monomer, contains the monomer whose glass transition temperature of a homopolymer is 50 degreeC or more in the ratio of 60 weight% or less, The adhesive sheet. 13. The method according to any one of claims 1 to 12,
A pressure-sensitive adhesive sheet comprising a support base material having a first surface and a second surface, wherein the pressure-sensitive adhesive layer is laminated on at least the first surface of the support base material. It is an adhesive sheet comprising an adhesive layer,
The pressure-sensitive adhesive layer includes a polymer A and a polymer B, which is a copolymer of a monomer having a polyorganosiloxane skeleton and a (meth)acrylic monomer,
The storage elastic modulus G' (150° C.) of the pressure-sensitive adhesive layer at 150° C. is 10,000 Pa or more and 90,000 Pa or less, the pressure-sensitive adhesive sheet.

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