TWI677546B - Adhesive, adhesive sheet and display - Google Patents

Abstract

The present invention relates to a display material constituting a material for bonding at least a surface of a bonding side, and an adhesive agent with other display material constituting materials. The above-mentioned adhesive agent contains a polymer constituting monomer. The unit contains a (meth) acrylate polymer (A) having a reactive functional monomer, an active energy ray curable component (B) having more than two functions, and a thermal bridging agent (C). The composition is cured by thermal bridging and active energy ray. The content of the active energy ray-curable component (B) in the adhesive composition is to make the bridging ratio (G1) of the adhesive, and The bridging ratio (G2) of the adhesive obtained by subjecting the adhesive composition other than the active energy ray-curable component (B) in the adhesive composition to thermal bridging is substantially equal; in addition, When the adhesive layer has a thickness of 600 μm and a width of 10 mm, in a 23 ° C, 50% RH environment, the maximum stress can be reached at a measurement length of 20 mm and an extension speed of 200 mm / min. 2.8N or more.

Description

Adhesive, adhesive sheet and display

The present invention relates to a display obtained by using an adhesive and an adhesive sheet for adhering components of a display, and an adhesive layer using the adhesive sheet.

Recently, various mobile electronic devices, such as mobile phones and tablet terminals, are equipped with display bodies (displays) used for display body modules such as liquid crystal elements, light-emitting diodes (LED elements), and organic light-emitting diodes (organic EL) elements. .

When it comes to the screen, a protective panel is usually installed on the surface side of the display module. A gap is formed between the protective panel and the display module, so that even if the protective panel is deformed by external force, the deformed protective panel will not touch the display module. group.

However, if there is an air layer as mentioned above, the light reflection loss caused by the refractive index difference between the protective panel and the air layer and the refractive index difference between the air layer and the display module is large, and the refractive index is not good. The reflection loss of light becomes large, causing a problem of poor display quality.

Therefore, the gap between the protective panel and the display body module is filled with an adhesive, which leads to a proposal to optimize the display image quality. However, on the side of the display body module of the protection panel, the frame-shaped printing layer will exist as a step difference. If the adhesive layer does not track the step difference, the adhesive layer will float around the step difference, which results in The reflection of light is lost, so step tracking is required for the above adhesive layer.

In order to solve the above-mentioned problems, Patent Document 1 discloses that as an adhesive layer that fills the gap between the protective panel and the display body module, the storage modulus (G ') is 1.0 in an environment of 25 ° C and 1Hz. × 10 ⁵ Pa or less, and bridging rate of more than 40% of the adhesive.

[Prior technical literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2010-97070

In Patent Document 1, when the adhesive layer is placed at normal temperature, the storage modulus is low, so it is necessary to improve the step tracking property. In addition, through other methods, reducing the bridging degree of the thermal bridging type adhesive, that is, the bridging rate, and improving the tracking of the step difference are also considered methods. However, in the same way, if the storage elasticity or bridging rate is reduced, the film strength of the adhesive layer is reduced, and the processability is also deteriorated. For example, when the adhesive sheet is separated and processed, the adhesive will adhere to the blade surface and occur. The adhesive layer may be partially defective.

The present invention has been made in view of such a situation. The object is to provide an adhesive and an adhesive sheet which have excellent segment tracking and exhibit high film strength, and a display body obtained by using the adhesive sheet.

In order to achieve the above object, first, the present invention provides an adhesive agent, which is a display body constituting part for bonding at least the surface on the bonding side Materials, and other display materials constituting members of the adhesive. It is characterized in that the adhesive is a (meth) acrylate polymer (A) containing a reactive functional monomer in a unit containing a polymer constituting monomer, and has a bifunctional or more active energy ray curability. The adhesive composition of the component (B) and the thermal bridging agent (C) is cured by thermal bridging and active energy rays. The content of the active energy ray-curable component (B) in the adhesive composition is to make the bridging ratio (G1) of the adhesive and to cure the active energy ray in the adhesive composition. The bridging ratio (G2) of the adhesive obtained by subjecting the adhesive composition other than the component (B) to thermal bridging is substantially equal. In addition, when the adhesive layer has a thickness of 600 μm and a width of 10 mm, the maximum stress is extended to the breaking elongation at a measurement length of 20 mm and an extension speed of 200 mm / min in an environment of 23 ° C and 50% RH. Up to 2.8N (Invention 1).

If the adhesive agent concerning the said invention (invention 1) satisfies the said conditions, it will have the outstanding level tracking property and high film strength.

In the above invention (Invention 1), the bridging ratio (G1) is preferably 40 to 80% (Invention 2).

In the above invention (Inventions 1, 2), in the case where the thickness of the adhesive layer is 600 μm and the width is 10 mm, the breaking elongation at a length of 20 mm and an extension speed of 200 mm / minute is measured in an environment of 23 ° C and 50% RH The degree is preferably 1000% or more (Invention 3).

In the above inventions (Inventions 1 to 3), the weight average molecular weight of the (meth) acrylate polymer (A) is preferably 200,000 to 1 million (Invention 4).

In the above inventions (Inventions 1 to 4), the (meth) acrylate polymer (A) contains the above-mentioned reactivity-containing polymer as a monomer unit constituting the polymer. The functional group monomer is preferably 5 to 30% by mass (Invention 5).

In the above inventions (Inventions 1 to 5), the reactive functional group of the reactive functional group-containing monomer is a carboxyl group and / or a hydroxyl group, and the bridging agent (C) is preferably an isocyanate bridging agent and / or an epoxy resin bridging agent. (Invention 6).

Second, the present invention provides an adhesive sheet (invention 7) with an adhesive layer made of the above-mentioned adhesive (inventions 1 to 6).

In the above invention (Invention 7), the thickness of the adhesive is preferably 10 to 400 μm (Invention 8).

In the above invention (Inventions 7, 8), the adhesive sheet has two release sheets, and the adhesive layer is preferably sandwiched by the release sheet so as to be in contact with the release surfaces of the two release sheets (Invention 9) .

Thirdly, the present invention provides a display body including a display body constituting member, another display body constituting member capable of adhering at least a surface on an adhering side, a display body constituting member, and a display body constituting member adhered thereto. Display body of the adhesive layer. It is characterized in that the adhesive layer is an adhesive layer of the adhesive sheet (Inventions 7 to 9).

In the above-mentioned invention (Invention 10), when the above-mentioned step is viewed from a plane, it may be a frame-like shape (Invention 11).

The adhesive layer and the adhesive layer of the adhesive sheet according to the present invention have excellent tracking performance and high film strength. In the case of a display body made using such an adhesive sheet, the adhesive layer can track the step difference in the case of a step difference on the bonding side. After a durable condition, it is still difficult to produce a gap or an interval between the step difference and the adhesive. The air bubble and the adhesive layer can keep the gap filled.

1‧‧‧adhesive sheet

11‧‧‧Adhesive layer

12a, 12b ‧‧‧ peeling sheet

2‧‧‧ Display

21‧‧‧The first display body constituent material

22‧‧‧Second display component

3‧‧‧print layer

(FIG. 1) A cross-sectional view of an adhesive sheet according to an embodiment of the present invention.

(FIG. 2) A sectional view of a laminated body according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described.

[Adhesive]

The adhesive according to this embodiment is an adhesive for adhering one type of display constituent member having a step difference on at least the side surface and other display constituent constituent members. The display body and the constituent parts of the display body will be discussed later.

The adhesive according to this embodiment is a (meth) acrylate polymer (A) containing a reactive functional group-containing monomer as a monomer unit constituting a polymer, and is cured with an active energy ray having two or more functions. The adhesive composition (B) and the thermal bridging bridging agent (C) (hereinafter referred to as "adhesive composition P") are cured by thermal bridging and active energy rays. It is speculated that in this adhesive, the (meth) acrylate polymer (A) is bridged by the bridging agent (C) to form a three-dimensional network structure, and the active energy ray-curable components (B) are polymerized with each other and entangled in In the above-mentioned three-dimensional mesh structure, this structure is hereinafter referred to as "structure X". In addition, in the patent specification of the present invention, (meth) acrylic acid refers to all acrylic acid and methacrylic acid, and the same applies to other similar terms. In addition, the concept of "copolymer" is also included in "polymer".

The content of the active energy ray-curable component (B) of the above-mentioned adhesive composition P is to remove the activity from the above-mentioned adhesive composition P in order to achieve the bridging ratio (G1) of the adhesive according to the embodiment. Viscosity of energy ray curable component (B) The bridging ratio (G2) of the adhesive (hereinafter referred to as "adhesive H") formed after the adhesive composition is thermally bridged is practically the same. In addition, the "actually the same" as used herein refers to a level in which the rate of change of the bridge rate that appears later is 15% or less.

Regarding the change rate of the bridging rate, the adhesive composition according to the present embodiment is G1 (%), so that the self-adhesive composition P excludes the active energy ray-curable component (B). When the bridging ratio of the adhesive H formed by thermal bridging is G2 (%), it can be expressed by the following formula.

Change rate of bridging rate (%) = ((G1-G2) / G2) × 100

In the adhesive according to this embodiment, the change rate of the bridging rate is preferably 0 to 15%, more preferably 0 to 10%, and particularly good 0 to 4%. The method of measuring the bridging ratio is the same as the experimental example described later.

In addition, in the case where the adhesive according to this embodiment is an adhesive layer having a thickness of 600 μm and a width of 10 mm, the extension is measured at a length of 20 mm and an extension speed of 200 mm / min in an environment of 23 ° C. and 50% RH To the elongation at break, the maximum stress must be above 2.8N. Thereby, it is possible to obtain a film strength sufficient to prevent problems such as adhesive defect of the adhesive layer during cutting. From the same viewpoint, the above-mentioned maximum stress is preferably 3N or more, and more preferably 4N or more. On the other hand, although the upper limit of the maximum stress is not particularly limited, in order not to deteriorate the step tracking rate, it is preferably 7N or less, and more preferably 6N or less. The specific method of this tensile test is the same as the experimental example described later. Such a maximum stress can be achieved when the adhesive composition P contains a predetermined amount of an active energy ray-curable component (B).

In the adhesive according to the present embodiment, the adhesive composition P containing the active energy ray-curable component (B) is thermally bridged by the above-mentioned amount. Cured with active energy ray, it is estimated that it can be formed in the three-dimensional network structure formed by (meth) acrylate polymer (A) and bridging agent (C). Structure X of the curable component (B). With this structure X, the adhesive according to the present embodiment exhibits excellent stress relaxation properties, and also has excellent step-tracking properties. Therefore, when the display surface constituting member with a step difference on the bonding surface is bonded to other display member constituting members, the adhesive according to this embodiment can track the step well. After setting the durability condition, the step difference and adhesion It is still difficult to generate voids or bubbles between the agents, and the adhesive layer can maintain the full state of the step (hereinafter, the step tracking after setting the durability conditions is referred to as "step tracking"). In addition, according to the above-mentioned structure X, the adhesive related to this embodiment exhibits high film strength. Therefore, for example, during punching of the adhesive sheet, the adhesive can be prevented from adhering to the blade surface and the adhesive can be generated. Part of the layer is missing.

(1) (meth) acrylate polymer (A)

The (meth) acrylate polymer (A) includes a reactive functional group-containing monomer as a monomer unit constituting the polymer. The reactive functional group-containing monomer reacts with the original reactive functional group bridging agent (C) to form a bridging structure.

The (meth) acrylate polymer (A), as a monomer unit constituting the polymer, preferably contains a reactive functional group-containing monomer, and preferably has a hydroxyl monomer (hydroxyl-containing monomer) in the molecule, A monomer having a carboxyl group (carboxyl group-containing monomer), a monomer having an amino group in the molecule (amino group-containing monomer), and the like. Among them, a hydroxyl-containing monomer and a carboxyl-containing monomer having excellent reactivity with an isocyanate bridging agent or an epoxy resin bridging agent are preferred.

Hydroxyl-containing monomers, such as: 2-hydroxyethyl (meth) acrylate, (formaldehyde (Meth) acrylic acid 2-hydroxypropyl, 3-hydroxypropyl (meth) acrylate, 2-hydroxyethyl (butyl) methacrylate, 3-hydroxybutyl (meth) acrylate, (meth) acrylic acid 4 -A hydroxyalkyl (meth) acrylate such as hydroxybutyl. Among them, in the obtained (meth) acrylate polymer (A), from the viewpoint of reactivity with a hydroxy bridging agent (C) and copolymerizability of other monomers, 2-hydroxyethyl (meth) Acrylate or 4-hydroxybutyl (meth) acrylate is preferred. These can be used alone or in combination of two or more.

Carboxyl-containing monomers, for example: acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, citraconic acid and other ethylenically unsaturated carboxylic acids, etc., wherein the (meth) acrylate polymer ( In A), from the viewpoint of reactivity with a hydroxy bridging agent (C) and copolymerizability of other monomers, acrylic acid is preferred. These can be used alone or in combination of two or more.

Examples of the amino-containing monomer include ethyl (meth) aminoacrylate and ethyl (meth) n-butylaminoacrylate. These can be used alone or in combination of two or more.

The (meth) acrylate polymer (A), as a monomer unit constituting the polymer, preferably has 5 to 30% by mass of a reactive functional group-containing monomer, more preferably 7 to 25% by mass, and particularly preferably 10 to 20% by mass; if the content of the reactive functional group-containing monomer is 5% by mass or more, a bridging point can be ensured and a good structure X can be formed. In addition, if the content of the reactive functional group-containing monomer is 30% by mass or less, desired adhesiveness can be easily obtained.

The (meth) acrylate polymer (A), as the reactive functional group-containing monomer constituting the polymer, contains a hydroxyl-containing monomer, and its content is preferably 10 to 25% by mass, and more preferably 15-20% by mass. In addition, (methyl) The acrylate polymer (A) is a reactive functional group-containing monomer constituting the polymer. When the carboxyl group-containing monomer is contained, the content is preferably 8 to 25% by mass, and more preferably 10 to 15% by mass. %.

As a monomer unit constituting the polymer, the (meth) acrylate polymer (A) is preferably an alkyl (meth) acrylate containing 1 to 20 carbon atoms in the alkyl group. The adhesive has good adhesion. In this alkyl (meth) acrylate, hard monomers described later are excluded.

In the case of alkyl (meth) acrylic acid having 1 to 20 carbon atoms in the alkyl group, for example, methyl acrylate, ethyl acrylate, (meth) acrylate propyl, (meth) acrylate, (formyl) N-butyl acrylate, n-pentyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, (meth) ) N-decyl acrylate, n-dodecyl (meth) acrylate, nutmeg (meth) acrylate, palmitate (meth) acrylate, stearin (meth) acrylate, and the like. Among them, from the viewpoint of further improving the adhesion, a (meth) acrylic acid ester having 1 to 8 carbon atoms in an alkyl group is preferred, and a n-butyl (meth) acrylic acid and (meth) acrylic acid are more preferable. 2-ethylhexyl. These can be used alone or in combination of two or more.

The (meth) acrylate polymer (A), as a monomer unit constituting the polymer, the number of carbon atoms of the alkyl group is preferably from 40 to 95% by mass containing the alkyl (meth) acrylate from 1 to 20 It is more preferable to contain 50 to 93% by mass, and particularly preferable to contain 55 to 90% by mass.

When the display body is subjected to high temperature and high humidity conditions, bubbles may be generated near the position of the step difference, or when the gas is exhausted from the plastic plate that protects the panel, abnormal bubbles such as bubbles, floating, and peeling may occur. For this, as (meth) c The polymer monomer unit composed of the acrylate polymer (A) is preferably a homopolymer containing a hard monomer having a glass transition temperature (Tg) of 70 ° C or higher. If the polymer unit composed of the (meth) acrylate polymer (A) contains the above-mentioned hard monomer, the cohesive force of the produced adhesive will be improved, and the anti-foaming property for the display body will be improved. And better. In particular, among the monomer units constituted by the (meth) acrylate polymer (A), those having a lower glass transition temperature (Tg) of a homopolymer such as 2-ethylhexyl (meth) acrylate (for example, : Tg is preferably below -30 ° C, more preferably below -60 ° C) as the main component, because the cohesive force tends to decrease, it is better to use the above-mentioned hard monomer. The glass transition temperature (Tg) of the hard monomer as a homopolymer is preferably 75 to 200 ° C, and more preferably 80 to 180 ° C. Further, as the reactive functional group-containing monomer of the (meth) acrylate polymer (A), when a carboxyl group-containing monomer is used, a certain degree of cohesive force can be obtained through the monomer. Therefore, in this case, the above-mentioned hard monomer is used less often.

Examples of the hard monomer include methyl methacrylate (Tg 105 ° C), isobornyl acrylic acid (Tg94 ° C), isobornyl ester (Tg180 ° C), acrylomorpholine (Tg145 ° C), adamantane acrylic acid (Tg115 ° C), Amantadine (Tg141 ° C), dimethylacrylamide (Tg89 ° C), acrylamide (Tg165 ° C), and the like. These can be used alone or in combination of two or more.

Among the above-mentioned hard monomers, from the viewpoint of preventing negative effects on other properties such as adhesion and transparency and allowing the hard monomers to exhibit better performance, methyl methacrylate, isobornyl acrylate, and Acrylic morpholine is preferred; from the standpoint of less causing poor step tracking, isobornyl acrylic and acrylic morpholine are better.

(Meth) acrylate polymer (A) as the polymer The monomer unit preferably contains 10 to 45% by mass of the hard monomer, and more preferably 15 to 30% by mass. When the above-mentioned hard monomer is contained in an amount of 10% by mass or more, it is expected that the foaming resistance improvement effect can be obtained through the monomer unit. On the other hand, if the above-mentioned hard monomer contains a content of 45% by mass or less, the relative shortage of other monomer units in the (meth) acrylate polymer (A) can be prevented, resulting in stickiness. Adhesive with better adhesiveness and followability.

The (meth) acrylate polymer (A) may contain other monomers as a monomer unit constituting the polymer as required. In terms of other monomers, in order not to hinder the function of the reactive functional group-containing monomer, it is preferable to use a reactive functional group-free monomer. Examples of such monomers include: (meth) acrylate alkoxyalkyl (meth) acrylate, (meth) acrylate ethoxyethyl, (meth) acrylate ethoxyethyl, and the like. Non-bridged (meth) acrylates such as hexyl acrylic acid, N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, etc. Tertiary amino (meth) acrylate, vinyl acetate, styrene, etc. These can be used alone or in combination of two or more.

The polymerization mode of the (meth) acrylate polymer (A) may be a random copolymer or a block copolymer.

The weight average molecular weight of the (meth) acrylate polymer (A) is preferably 200,000 to 1,000,000, more preferably 300,000 to 900,000, and particularly preferably 400,000 to 700,000. In addition, in the patent specification of the present invention, the weight average molecular weight is converted into standard polystyrene measured by gel permeation chromatography (GPC).

The weight average molecular weight of the (meth) acrylate polymer (A) is the same as the above. When the weight average molecular weight is in the lower range, it can achieve excellent output through step-tracking. Show adhesive. If the weight average molecular weight of the (meth) acrylate polymer (A) exceeds 1 million, the step tracking will be deteriorated. On the other hand, if the weight average molecular weight of the (meth) acrylate polymer (A) is less than 200,000, it will cause the durability of the adhesive to deteriorate.

Further, in the adhesive composition P, the (meth) acrylate polymer (A) may be used alone or as a mixture of two or more kinds.

(2) Curable ingredients of active energy ray (B)

In the case where the adhesive composition P is the above-mentioned blending amount, since the active energy ray-curable component (B) is contained in two or more functional groups, the adhesive composition produced after curing the adhesive composition P not only It has excellent tracking performance and high film strength.

The active energy ray-curable component (B) is not particularly limited as long as it does not interfere with the effects of the present invention and is a component that will cure under active energy ray irradiation. Any of monomers, oligomers, and polymers may be used. Mixtures of ingredients are also good. Among these, a polyfunctional acrylate monomer having a molecular weight of less than 1,000 and having excellent compatibility with the (meth) acrylate polymer (A) and the like is preferred.

Examples of polyfunctional acrylate monomers with a molecular weight of less than 1,000 include 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (Meth) acrylate, polyethylene glycol di (meth) acrylate, neopentyl glycol (meth) acrylate, hydroxypivalate neopentyl glycol di (meth) acrylate, dicyclopentyl Di (meth) acrylate, caprolactone-modified dicyclopentenyl di (meth) acrylate, ethylene oxide-modified phosphate di (meth) acrylate, bis (propyleneoxyethyl) Isocyanurate, allyl cyclohexyl di (meth) acrylate, ethoxylated bisphenol A diacrylate, 9, 9- Bis [4- (2-propenyloxyethoxy) phenyl] difunctional fluorene, etc .; trimethylolpropane tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, propionic acid Modified dipentaerythritol tri (meth) acrylate, pentaerythritol tri (meth) acrylate, propylene oxide modified trimethylolpropane tri (meth) acrylate, tris (propenyloxyethyl) isopropyl 3-functional types such as cyanurate, caprolactone ε-modified tri- (2- (meth) acryloxyethyl) isocyanurate; diglycerol tetra (meth) acrylate, pentaerythritol tetra 4-functional forms such as (meth) acrylates; 5-functional forms such as propionic acid-modified dipentaerythritol penta (meth) acrylate; dipentaerythritol hexa (meth) acrylates, caprolactone-modified dipentaerythritol hexa (methyl) ) 6-functional type such as acrylate. These can be used alone or in combination of two or more.

The active energy ray-curable component (B) may also be an active energy ray-curable acrylate oligomer. The weight average molecular weight of the acrylate oligomer is preferably 50,000 or less. Examples of such acrylate oligomers include polyester acrylate, epoxy acrylate, urethane acrylate, polyether acrylate, polybutadiene acrylate, and silicone acrylate.

The weight average molecular weight of the acrylate oligomer is preferably 50,000 or less, more preferably 500 to 50,000, and particularly preferably 3,000 to 40,000. These acrylate oligomers can be used alone or in combination of two or more.

In addition, as the active energy ray curable component (B), adduct acrylates obtained by introducing a group having a (meth) acryloyl group into a side chain may be used. polymer. Such an adduct acrylate-based polymer can be obtained by using a copolymer of (meth) acrylate and a monomer having a bridging functional group in the molecule, A compound of a bridging functional group is obtained by reacting a part of the bridging functional group of the copolymer.

The weight average molecular weight of the adduct acrylic polymer is preferably about 50,000 to 900,000, and more preferably about 100,000 to 500,000.

The active energy ray-curable component (B) can be selected from the above-mentioned multifunctional acrylate monomers, acrylate oligomers, and adduct acrylate polymers, and can also be used in combination of two or more types. Active-energy-ray-curable components other than the above-mentioned components are used.

Although the content of the active energy ray-curable component (B) in the adhesive composition P is as described above, in detail, from the viewpoint of obtaining an appropriate film strength, when the (meth) acrylate polymer (A) is determined When it is 100 parts by mass, it is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, and particularly preferably 1 part by mass or more. On the other hand, in the bridging ratio (G1) of the adhesive according to this embodiment, in the adhesive composition P, heat is applied to the adhesive composition excluding the active energy ray-curable component (B). Bridging makes the bridging ratio (G2) of the produced adhesive H practically the same. From the viewpoint of obtaining superior segment tracking, the content of the active energy ray curable component (B) is in (A When the base) acrylate polymer (A) is 100 parts by mass, it is preferably 4 parts by mass or less, more preferably 3 parts by mass or less, particularly preferably 2.5 parts by mass or less, and most preferably less than 2.0 parts by mass.

(3) bridging agent (C)

The adhesive composition P contains a thermal bridging bridging agent (C) and forms a three-dimensional network structure by heating the bridging (meth) acrylate polymer (A), thereby improving the cohesive force of the produced adhesive. And impart durability to the adhesive.

As long as the bridging agent (C) can be polymerized with (meth) acrylate The reactive functional group of the compound (A) can be reacted, for example: isocyanate bridging agent, epoxy resin bridging agent, amine bridging agent, melamine bridging agent, aziridine bridging agent, hydrazine bridging agent, aldehyde Bridging agent, oxazoline bridging agent, metal alkoxide bridging agent, metal chelate bridging agent, metal salt bridging agent, ammonium salt ester bridging agent, etc. In the above-mentioned bridging agent, when the reactive functional group of the (meth) acrylate polymer (A) is a hydroxyl group, it is preferable to use an isocyanate bridging agent having excellent reactivity with the hydroxyl group; if the (meth) acrylate polymer (A When the reactive functional group of) is a carboxyl group, it is preferable to use an epoxy resin bridging agent having excellent reactivity with a carboxyl group. The bridging agent (C) may be used alone or in combination of two or more.

The isocyanate bridging agent must contain an isocyanate compound. Examples of the isocyanate compound include aromatic polyisocyanates such as diisocyanate, diphenylmethane diisocyanate, and cyanate; aliphatic polyisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, and hydrogenated diphenyl Cycloaliphatic polyisocyanates such as methane diisocyanate, their ureton bodies, isocyanurate bodies, and low molecular weight active hydrogen containing ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, castor oil, etc. Reactant adducts of compounds and the like. Among them, from the viewpoint of reactivity with hydroxyl groups, trimethylolpropane-modified aromatic polyisocyanates, in particular trimethylolpropane-modified diisocyanate toluene, and trimethylolpropane-modified Cyanate is particularly preferred.

Examples of epoxy resin bridging agents: 1,3-bis (N, N'-diglycidylaminomethyl) cyclohexane, N, N, N ', N'-tetraglycidyl-m-xylylene Amine, ethylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane diglycidyl ether, diglycidylaniline, diglycidylamine, and the like.

The content of the bridging agent (C) in the adhesive composition P is preferably 0.001 to 2 masses when the (meth) acrylate polymer (A) is set to 100 parts by mass. Part, more preferably 0.01 to 1 part by mass, and particularly good part 0.02 to 0.3 part by mass. When the content of the bridging agent (C) is 0.001 parts by mass or more, the durability of the produced adhesive can be improved; when the content of the bridging agent (C) is 2 parts by mass or less, appropriate bridging can ensure The resulting adhesive has step-tracking performance.

(4) Various additives

For the adhesive composition P, various additives commonly used for acrylic adhesives can be used as required. For example: silane coupling agent, photopolymerization initiator, antistatic agent, tackifier, antioxidant, ultraviolet absorber, light stabilizer, softener, filler, refractive index adjuster, etc.

As for the silane coupling agent, an organosilicon compound having at least one alkoxysilyl group in the molecule and a good compatibility with the (meth) acrylate polymer (A) are preferred. When the adhesive is used for optical applications, a translucent silane coupling agent is preferred.

Examples of such silane coupling agents include polymerizable unsaturated silicon compounds such as vinyltrimethyl, vinyltriethoxysilane, and methacrylidine, 3-glycidoxypropyl, 2- (3,4 -Epoxycyclohexyl) ethyltrimethyl, and other silicon compounds with epoxy resin structure, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyldimethoxymethyl Mercapto-containing silicon compounds such as silane, 3-aminopropyl, N- (2-aminoethyl) -3-aminopropyl, N- (2-aminoethyl) -3-aminopropylmethyldimethoxy Aminosilane-containing compounds, such as aminosilane, 3-chloropropyltrimethoxysilane, 3-isocyanatepropyltriethoxysilane, or at least one of them with methyltriethoxysilane, methyltriethoxysilane, Alkyl silicon-containing compounds such as ethyltriethoxysilane, methyltrimethoxysilane, and ethyltrimethyl and their concentrates. The above ingredients can be used alone or in combination of two or more.

When the amount of the silane coupling agent is 100 parts by mass of the (meth) acrylate polymer (A), it is preferably 0.01 to 1.0 parts by mass, and more preferably 0.05 to 0.5 parts by mass.

Moreover, as an active energy ray which irradiates the adhesive composition P, when ultraviolet rays are used, it is preferable that the adhesive composition P contains a photopolymerization initiator. By containing a photopolymerization initiator, the active energy ray-curable component (B) can be efficiently cured, and the polymerization curing time and the amount of active energy ray exposure can be reduced.

Examples of such photopolymerization initiators include benzoin, benzoin methyl ether, benzoin ether, benzoin isopropyl ether, benzoin-N-butyl ether, benzoin isobutyl ether, benzene Ethyl ketone, dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2- Methyl-1-phenyl-propane-1-one, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholine-propan-1 -Ketone, 4- (2-hydroxyethoxy) phenyl-2- (hydroxy-2-propyl) ketone, benzophenone, p-phenylbenzophenone, 4,4'-diethyl Aminobenzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzophenone dimethyl ketal, acetophenone di Methyl ketal, p-dimethylaminobenzoate, oligo [2-hydroxy-2-methyl-1 [4- (1-methylvinyl) phenyl] acetone], 2,4, 6-trimethylbenzylidene-diphenyl-phosphine oxide and the like. The above ingredients can be used alone or in combination of two or more.

When the photopolymerization initiator has an active energy ray-curable component (B) of 100 parts by mass, it is preferably 2 to 15 parts by mass, and more preferably 4 to 12 parts by mass.

(5) Manufacture of adhesive composition

The adhesive composition P can be a (meth) acrylate polymer (A) obtained by producing a (meth) acrylate polymer (A), an active energy ray-curable component (B), and a bridging agent (C ) After mixing, add additives as needed.

The (meth) acrylate polymer (A) can be produced by polymerizing the monomer mixture constituting the polymer by a general radical polymerization method. The polymerization of the (meth) acrylate polymer (A) can be used as required. The polymerization initiator was subjected to a solution polymerization method. Examples of the polymerization solvent include ethyl acetate, n-butyl acetate, isobutyl acetate, toluene, acetone, hexane, and methyl ethyl ketone, and two or more of them may be used in combination.

Examples of the polymerization initiator include azo compounds and organic peroxides, and two or more of them may be used in combination. Examples of azo compounds: 2,2'-azobisisobutyronitrile, 2,2'-azobis (2-methylbutyronitrile), 1,1'-azobis (cyclohexane-1- Nitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (2,4-dimethyl-4-methoxyvaleronitrile), di Methyl 2,2'-azobis (2-methylpropionate), 4,4'-azobis (4-cyanovaleric acid), 2,2'-azobis (2-hydroxymethyl) Propionitrile), 2,2'-azobis [2- (2-imidazolin-2-yl) propane] and the like.

Examples of organic peroxides include benzophenazine peroxide, t-butylperbenzoate, cumene hydroperoxide, diisopropylperoxydicarbonate, and di-N-propylperoxydi (2- (Ethoxyethyl) peroxydicarbonate, tert-butylperoxyneodecan, tert-butylperoxyne, (3,5,5-trimethylhexyl) peroxide, dipropanyl Oxides, diethylammonium peroxide, etc.

In addition, in the above polymerization process, if a chain transfer agent such as 2-mercaptoethanol is used, the weight average molecular weight of the polymer produced can be adjusted.

If a (meth) acrylate polymer (A) is produced, an active energy ray-curable component (B) and a bridge are added to the (meth) acrylate polymer (A) solvent. Agent (C), and additives are added as required, and the adhesive composition P can be obtained after thorough mixing.

(6) Manufacturing of adhesives

The above adhesive composition P is applied to a reference object as required, and then subjected to thermal bridging, and cured by irradiation with active energy rays (active energy ray curing) to obtain the adhesive agent according to this embodiment. .

The thermal bridging of the adhesive composition P can be performed by heat treatment, and this heat treatment can also be performed at the same time when the adhesive composition P is applied and then dried. The preferred heating temperature for the heat treatment is 50 to 150 ° C, and more preferably 70 to 120 ° C. In addition, the preferred heating time is 10 seconds to 10 minutes, and more preferably 50 seconds to 2 minutes.

The so-called active energy ray here means that there are energy quanta in an electromagnetic wave or a charged particle beam. Specifically, examples include ultraviolet rays and electron beams. Among the active energy rays, ultraviolet rays which are easy to handle are particularly preferred.

Ultraviolet irradiation can be performed using high-pressure mercury lamps, Fusion H lamps, xenon lamps, etc. The ultraviolet irradiation amount is preferably 50 ~ 1000mW / cm ² . In addition, the light amount is preferably about 50 to 10,000 mJ / cm ² , more preferably 80 to 5000 mJ / cm ² , and particularly preferably 200 to 2000 mJ / cm ² . On the other hand, an electron beam accelerator can be used for the electron beam irradiation, and the irradiation amount of the electron beam is preferably about 10 to 1000 krad.

If the adhesive composition P is heat-treated, the (meth) acrylate polymer (A) and the bridging agent (C) react to form a bridging structure-three-dimensional network structure. In addition, when the adhesive composition P is irradiated with an active energy ray, the active energy ray-curable component (B) is polymerized, and is cured while being wound around the three-dimensional network structure. In this way, the adhesion related to this embodiment is produced. The agent has superior segment tracking and high film strength.

In addition, when producing the adhesive according to this embodiment, heat treatment may be performed first and then the active energy rays may be irradiated, or two treatment methods may be performed simultaneously. In addition, after heat treatment or irradiation with active energy rays, it is placed in normal temperature (for example, 23 ° C, 50% RH), and a curing period of about 1 to 2 weeks is preferred.

(7) Bridge rate

The bridging ratio (G1) of the adhesive according to this embodiment is preferably 40 to 80%, more preferably 45 to 70%, and particularly preferably 50 to 65%. If the bridging ratio (G1) is more than 40%, good film strength can be ensured. In addition, if the bridging ratio (G1) is 80% or less, a good adhesive segment tracking performance can be ensured.

(8) Elongation at break

When the adhesive according to this embodiment is used for an adhesive layer with a thickness of 600 μm and a width of 10 mm, it breaks when the length is 20 mm and the extension speed is 200 mm / min in an environment of 23 ° C and 50% RH. The elongation is more than 1000%, more preferably 1100 ~ 4000%, and more preferably 1200 ~ 2500%. The specific method of this extension experiment is the same as the experimental example described later.

The adhesive according to this embodiment is obtained by curing the above-mentioned adhesive composition P thermally and curing the active energy ray to achieve the above-mentioned breaking elongation. When the elongation at break is as high as described above, the step tracking of the adhesive becomes more superior.

(9) Segment tracking rate

The step tracking rate (%) of the adhesive according to this embodiment shown in the following formula is preferably 20% or more, more preferably 25 to 80%, and particularly good 30 to 70%.

Segment tracking rate (%) = {(After the endurance test is set, there is no gap or air bubbles adhere State-maintained step height (μm)) / (thickness of adhesive layer)) × 100

The method of measuring the step tracking rate is the same as the experimental example described later.

The adhesive according to this embodiment is formed by curing the above-mentioned adhesive composition P thermally and curing the active energy ray, so as to achieve a large step tracking rate as described above.

[Adhesive sheet]

As shown in FIG. 1, the adhesive sheet 1 according to this embodiment is composed of two peeling sheets 12 a and 12 b and the two peeling sheets 12 a and 12 b are bonded to each other so that the two peeling sheets 12 a and 12 b are bonded together. And 12b are composed of an adhesive layer 11 embedded between them. In addition, the release surface of the release sheet in the patent specification of the present invention refers to a release-side surface of the release sheet, and both the release-treated surface and the release-free surface without release treatment are included here.

(1) Adhesive layer

The adhesive layer 11 of the adhesive sheet 1 is composed of the above-mentioned adhesive, that is, the adhesive composition P is cured by thermal bridging and active energy rays, and then the adhesive is obtained.

The thickness of the adhesive layer 11 (value measured in accordance with JIS K7130) is preferably 10 to 1000 μm, more preferably 30 to 400 μm, and even more preferably 50 to 300 μm. In addition, only a single layer of the adhesive layer 11 may be formed, or a plurality of layers may be formed by lamination.

If the thickness of the adhesive layer 11 is less than 10 μm, sufficient step tracking may not be obtained. On the other hand, if the thickness of the adhesive layer 11 is 1000 μm or less, it has good processability.

(2) Release sheet

Examples of the release sheets 12a and 12b include a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a polymethyl film, a polyvinyl chloride film, a vinyl chloride copolymer film, and polyethylene terephthalate. Film, polynaphthalene film, polyterephthalate film, polyurethane film, ethylene vinyl acetate film, ionomer resin film, ethylene (meth) acrylic copolymer film, ethylene- (meth) acrylate copolymer As the physical film, polystyrene film, polycarbonate film, polyimide film, fluororesin film, etc., the bridge film of the above-mentioned film can also be used, and the laminated film of the above-mentioned film can also be used.

It is preferable that the peeling surface (particularly the surface which contacts the adhesive layer 11) of the said peeling sheet 12a, 12b is a peeling process. Examples of the release agent used in the peeling treatment include alkyd, silicone-based, fluorine-based, unsaturated polyester-based, polyolefin-based, and wax-based release agents. In addition, it is preferable that one of the release sheets 12a and 12b is a heavy release type release sheet having a large peeling force, and the other side is a light release type release sheet having a weak peeling force.

Although the thickness of the release sheets 12a and 12b is not particularly limited, it is generally about 20 to 150 μm.

(3) Manufacturing of adhesive sheet

As one manufacturing example of the adhesive sheet 1, the coating liquid of the above-mentioned adhesive composition P is coated on the release surface of one side 12a (or 12b) of the release sheet, and then the coating layer is heat-treated. The adhesive composition P is irradiated with active energy rays while being thermally bridged, so that the adhesive composition P is cured to form the adhesive layer 11. The other side of the formed adhesive layer 11 and the release surface of the release sheet 12b (or 12a) overlap each other, and this is used as the adhesive sheet 1. In addition, the above-mentioned irradiation of the active energy ray may be performed after the coating layer of the adhesive composition P is thermally bridged, and then the peeling surface of the release sheet 12b (or 12a) on the other side is overlapped on the coating layer. get on.

As another manufacturing example of the adhesive sheet 1, the above-mentioned coating liquid of the adhesive composition P is coated on the release surface of one of the release sheets 12a, the coating layer is heat-treated, and the adhesive composition P is thermally bridged. At the same time, the active energy ray is irradiated to cure the adhesive composition P to form a first adhesive layer. Next, the coating liquid of the adhesive composition P is coated on the release surface of the other release sheet 12b, and the coating layer is heat-treated. The active composition is irradiated with active energy rays while the adhesive composition P is thermally bridged to make the adhesive. The adhesive composition P is cured to form a second adhesive layer. Next, the two adhesive layers are bonded to each other to form the adhesive sheet 1 with the release sheet 12a to which the first adhesive layer is adhered and the release sheet 12b to which the second adhesive layer is attached. In addition, the adhesive sheet 1 is not obtained after the first adhesive layer and the second adhesive layer are formed separately, but when the respective coating layers are processed to the thermal bridging stage, they are connected at the same time. The adhesive sheet 1 was obtained by irradiating active energy rays.

As a method for applying the coating liquid of the above-mentioned adhesive composition P, for example, a bar coating method, a blade coating method, a roll coating method, a plate coating method, a mold coating method, a gravure coating method, or the like can be used. The heat treatment conditions of the adhesive composition P are the same as those described above.

In the above-mentioned adhesive sheet 1, since the step difference of the adhesive layer 11 is excellent, even after being adhered to a display constituent member having a step difference, the step difference and the adhesive layer are not easy even after being set in a durable condition. A gap or air bubble is generated between 11 and the adhesive layer 11 can fill the step. In addition, since the film strength of the adhesive layer 11 is high, for example, it is possible to prevent the adhesive from adhering to the blade surface during punching processing of the adhesive sheet 1, thereby causing a problem that the adhesive layer 11 is partially damaged.

(4) Haze value

Haze value (based on JIS) of the adhesive layer 11 according to this embodiment K7136: The value measured based on 2000) is preferably 3% or less, more preferably 2% or less, and more preferably 1% or less. If the haze is 3% or less, it has relatively high transparency and is suitable for optical applications.

(5) Adhesion

Since the adhesive sheet 1 of this embodiment can still exhibit excellent step tracking after durability conditions, the adhesive force (value measured based on JIS Z0237: 2009) is preferably 5N / 25mm or more, and more preferably 10N / 25mm or more, especially good 25N / 25mm or more. In addition, from the viewpoint of imparting reworkability to the adhesive sheet 1, the adhesive force is preferably 50 N / 25 mm or less, more preferably 40 N / 25 mm or less, and particularly preferably 35 N / 25 mm or less. The detailed experimental examples of the adhesion force test method are the same as those described.

[Display body]

As shown in FIG. 2, the display body 2 according to this embodiment adheres at least the first display body constituent member 21 (a display body constituent member) and the second display body constituent member 22 (the other displays) with stepped sides. Body constituting member), and an adhesive layer 11 which is located between the first display constituting member 21 and the second display constituting member 22 and is used for bonding the two. In the display body 2 according to the present embodiment, the first display body constituent member 21 has a step on the surface on the side of the adhesive layer 11. Specifically, the print layer 3 has a step.

Examples of the display body 2 include a liquid crystal (LCD) display, a light emitting diode (LED) display, an organic light emitting diode (organic EL) display, and electronic paper. A touch panel is also preferred.

In addition to the glass plate and the plastic plate, the first display body constituting member 21 is preferably made of a laminated body including these two items. In this case, generally, the print layer 3 will be on the first display body. Adhesive layer constituting member 21 11 sides form a border pattern.

The second display component 22 is a display module (such as a liquid crystal (LCD) module, a light emitting diode (LED) module, an organic light emitting diode (organic EL) module, etc.), or a part thereof (such as : Optical materials such as polarizing plates) are preferred.

The above glass plate is not particularly limited, and examples thereof include chemically strengthened glass, alkali-free glass, quartz glass, soda lime glass, barium and strontium glass, glass aluminate, lead glass, borosilicate glass, and barium borosilicate glass Wait. Although the thickness of the glass plate is not particularly limited, it is generally 0.1 to 5 mm, and preferably 0.2 to 2 mm.

The plastic plate is not particularly limited, and examples thereof include an acrylic plate and a polycarbonate plate. The thickness of the plastic plate is not particularly limited, but is generally 0.2 to 5 mm, and preferably 0.4 to 3 mm.

In addition, various functional layers (transparent conductive film, metal layer, silicon dioxide layer, hard plating layer, anti-glare layer, etc.) can be provided on one or both sides of the above glass plate and plastic plate, and optical components can also be laminated, transparent and conductive. Films and metal layers can also be patterned.

Examples of the above optical components include: polarizing plate (polarizing film), polarizing plate, retardation plate (phase retarding film), viewing angle compensation film, brightness enhancement film, contrast enhancement film, liquid crystal polymer film, diffusion film, hard-plated film, half Transflective film.

The material constituting the printed layer 3 is not particularly limited, and a known material may be used. The thickness of the printing layer 3, that is, the height of the step is preferably 3 to 45 μm, more preferably 5 to 35 μm, particularly preferably 7 to 25 μm, and most preferably 7 to 15 μm.

If the display body 2 is to be manufactured, for example, firstly, an adhesive sheet 1 Cut according to the corresponding size of the first display body constituent member 21 and the second display body constituent member 22, and when cutting, the thickness direction of the adhesive sheet 1 may be completely cut, or the other side peeling sheet of the adhesive sheet 1 may not be cut. 12b, half-cut the adhesive layer 11 and one side release sheet 12a. At this time, since the film strength of the adhesive layer 11 is very high, the problem that a part of the adhesive layer 11 is defective due to the adhesion of the adhesive can be suppressed.

Next, after peeling the one-side release sheet 12 a of the adhesive sheet 1, the exposed adhesive layer 11 of the adhesive sheet 1 is attached to the surface on the side where the printed layer 3 of the first display body constituent member 21 exists, and then self-adhesive. The other side of the release sheet 12 b is peeled off from the adhesive side 11 of the contact sheet 1, and the exposed adhesive layer 11 of the adhesive sheet 1 and the second display member 22 are bonded.

In the above process, when the adhesive layer 11 and the first display component 21 are bonded, since the adhesive layer 11 has excellent step-tracking performance, it is difficult to prevent the A gap is generated between the formed step and the adhesive layer 11, and the adhesive layer 11 can fill the step.

The embodiments described above are described for easy understanding of the present invention, and the scope of implementation of the present invention cannot be limited by this. Therefore, all design changes or equivalents belonging to the technical scope of each element described in the above embodiments should still fall within the scope of the patent of the present invention.

For example, either side of the release sheets 12a and 12b of the adhesive sheet 1 may be omitted, and the first display body constituent member 21 may have a step other than the printing layer 3 or may not have a step. In addition, not only the first display body constituent member 21 but also the second display body constituent member 22 is preferably applied when the adhesive layer 11 has a step.

[Example]

Hereinafter, the present invention will be described in more detail through examples and the like. The scope of the invention is not limited to these examples.

[Example 1]

1. Preparation of (meth) acrylate polymers

90 parts by mass of n-butyl acrylate and 10 parts by mass of acrylic acid were copolymerized to prepare a (meth) acrylate polymer, and the molecular weight of this (meth) acrylate polymer (A) was measured by a method described later The weight average molecular weight (Mw) is 400,000.

2. Preparation of adhesive composition

100 parts by mass of the (meth) acrylate polymer (A) obtained in the above process (in terms of solid content; the same shall apply hereinafter), which is different from the tris (acryloxyethyl) group of the active energy ray curable component (B) 0.1 parts by mass of cyanurate (manufactured by TOAGOSEI CO., LTD., Product name "M-315"), epoxy resin bridging agent (C) 1,3-bis (N, N-diglycidylcarbamate) Base) cyclohexane (manufactured by MITSUBISH GAS CHEMICAL COMPANY, INC., Product name "TETRAD-C" (solid content concentration: 100% by mass)) 0.05 parts by mass, and 3-glycidoxypropoxypropane as a silane coupling agent Based on 0.2 parts by mass of SHIN-ETSU Chemical Co., Ltd. (product name "KBM-403"), and 1-hydroxycyclohexylphenyl ketone (manufactured by BASF, product name) was added as a photopolymerization initiator. "IRGACURE184"), adding an amount equivalent to 10% by mass of the component (B), and thoroughly diluting with methyl ethyl ketone to obtain an adhesive composition coating solvent having a solid content concentration of 37% by mass.

The formulation of this adhesive composition is shown in Table 1. In addition, the codes and other details described in Table 1 are as follows: [(Meth) acrylate polymer]

BA: n-butyl acrylate

AA: Acrylic

2EHA: 2-ethylhexyl acrylate

MMA: methyl methacrylate

HEA: 2-ethylhexyl acrylate

IBXA: Isobornyl Acrylic

ACMO: Acrylic morpholine

VAc: vinyl acetate

〔Active energy ray curable component〕

M-315: Tris (acrylfluorenylethoxy) isocyanurate (manufactured by TOAGOSEI CO., LTD., Product name "M-315")

A-400: polyethylene glycol diacrylate (manufactured by SHIN-NAKAMURA CHEMICAL CO., LTD., Product name "A-400", molecular weight of polyethylene glycol: 400)

A-TMM-3: Pentaerythritol triacrylate (manufactured by SHIN-NAKAMURA CHEMICAL CO., LTD., Product name "A-TMM-3")

A-DPH: Dipentaerythritol hexaacrylate (manufactured by SHIN-NAKAMURA CHEMICAL CO., LTD., Product name "A-DPH")

[Bridge agent]

Epoxy resin-1: 1,3-bis (N, N'-diglycidylaminomethyl) cyclohexane (manufactured by MITSUBISH GAS CHEMICAL COMPANY, INC., Product name "TETRAD-C")

Epoxy resin-2: N, N, N ’, N'-tetraglycidyl-m-xylylenediamine (manufactured by MITSUBISH GAS CHEMICAL COMPANY, INC., Product name "TETRAD-X")

Isocyanate: Trimethylolpropane modified toluene diisocyanate (manufactured by SOKEN CHEMICAL & ENGINEERING CO., LTD., Product name "L-45")

3. Manufacturing of adhesive sheet

On one side of a polyethylene terephthalate film, a peeled surface of a heavily peeled release sheet (manufactured by LINTEC CORPORATION, product name "SP-PET752150") was peeled with a silicone release agent, and the obtained The application solvent of the adhesive composition is applied here with a blade coater. After the coating layer was heat-treated at 100 ° C for 2 minutes, ultraviolet rays were radiated under the following conditions to form a first adhesive layer having a thickness of 25 µm.

[UV irradiation conditions]

‧Light source: high pressure mercury lamp

‧Amount of light: 500mJ / cm ²

‧Illumination: 200mW / cm ²

In addition, the illuminance and light amount were confirmed with a UV illuminance and light meter "UVPF-36" manufactured by EYE GRAPHICS CO., LTD.

Similarly, on one side of a polyethylene terephthalate film, the release-treated surface of a light release-type release sheet (manufactured by LINTEC CORPORATION, product name "SP-PET382120") was peeled with a silicone release agent, The coating solvent of the obtained adhesive composition was apply | coated here with the blade coater. After the coating layer was heat-treated at 100 ° C for 2 minutes, ultraviolet rays were irradiated under the same conditions as described above, thereby forming a second adhesive layer having a thickness of 25 µm.

A heavy release-type release sheet attached from the first adhesive layer obtained above, and a light-release type release sheet attached from the second adhesive layer obtained above, The two adhesive layers were adhered to each other to form a pressure-sensitive adhesive sheet with a heavy release type adhesive sheet / adhesive layer (thickness: 50 μm) / light release type peeling sheet structure. The thickness of the adhesive layer is a value measured using a constant-pressure thickness gauge (manufactured by TECLOCK CORPORATION, product name "PG-02") based on JIS K7130.

[Examples 2 to 17, Comparative Examples 1 to 4]

The proportion of each monomer constituting the (meth) acrylate polymer (A), the weight average molecular weight of the (meth) acrylate polymer (A), the type and blending amount of the active energy ray-curable component (B), and the bridge The type and blending amount of the agent (C) and the blending amount with the silane coupling agent are shown in Table 1. Except for the changed part, an adhesive sheet was produced in the same manner as in Example 1. In addition, Comparative Examples 1 and 4 were not subjected to ultraviolet irradiation treatment.

The weight average molecular weight (Mw) is converted into polystyrene by colloidal permeation chromatography (GPC) and measured by the following conditions (GPC measurement).

<Measurement conditions>

‧GPC measuring equipment: manufactured by TOSOH CORPORATION, HLC-8020

‧GPC column (passed in the following order): made by TOSOH CORPORATION

TSK guard column HXL-H

TSK gel GMHXL (× 2)

TSK gel G2000HXL

‧Measurement solvent: tetrahydrofuran

‧Measured temperature: 40 ℃

[Experimental Example 1] (Measurement of Adhesive Force)

Unloading from the adhesive sheet obtained in Examples and Comparative Examples Sheet, the exposed adhesive layer is adhered to the easily-adhesive layer of a polyethylene terephthalate film (manufactured by TOYOBO CO., LTD., PET A4300, thickness: 100 μm) having an easily-adhesive layer, The laminated body was cut to a size of 25 mm in width and 100 mm in length, and this was used as a sample. After the heavy peeling type release sheet was unloaded on this sample, a soda-lime glass (manufactured by NIPPON SHEET GLASS CO., LTD.) Was stuck on the exposed adhesive layer.

After that, it was left under normal pressure conditions of 23 ° C and 50% RH for 24 hours. Using JIS Z0237: 2009 as the test standard, the peeling speed was 300 mm / min, and the peeling angle was 180 ° as the test conditions. A tensile tester (ORIENTEC Co., Ltd., product name "TENSILON") Test adhesion (N / 25mm). The results are shown in Table 2.

[Experimental Example 2] (Measurement of Haze Value)

About the adhesive layer of the adhesive sheet obtained by the Example and the comparative example, the haze meter (made by NIPPON DENSHOKU INDUSTRIES CO., LTD., And product name "NDH-2000" was used according to JIS K7361-1: 1997 as a reference | standard. ) Test the haze value (%). The results are shown in Table 2.

[Experimental Example 3] (Measurement of bridge rate)

The adhesive sheets obtained from the examples and comparative examples were cut into 80mm × 80mm, and the adhesive layer was coated in a net (mesh size 200) made of polyester (PE) and placed on a precision balance to measure the mass; based on the deduction The mass of the above mesh can be calculated as the net mass of the adhesive, and its mass is M1.

Next, the above-mentioned adhesive coated in a polyester mesh was immersed in ethyl acetate at room temperature (23 ° C) for 24 hours, and then the adhesive was taken out at a temperature of 23 ° C and a relative humidity of 50%. In the environment, air-dry for 24 hours, then put in an oven at 80 ° C for 12 hours. After drying, measure its mass with a precision balance, The net mass of the adhesive can be calculated from the mass of the net. Its mass is M2. The bridging rate (G1;%) is expressed as (M2 / M1) × 100. The results are shown in Table 2.

[Experimental Example 4] (Measurement of the rate of change in bridging rate)

Except that the active energy ray-curable component (B) was not added in the examples and comparative examples, an adhesive composition was produced in the same manner as described above. Next, this adhesive composition was used to prepare an adhesive sheet in the same manner as described above, except for those who were not treated with ultraviolet rays. For the adhesive layer of the obtained adhesive sheet, the bridging ratio (G2;%) was measured by the same method as in Experimental Example 3. This bridging ratio is taken as G2. When the bridging ratio measured in Experimental Example 3 is taken as G1, the rate of change (%) of the bridging ratio represented by the following formula can be calculated. The results are shown in Table 2.

Change rate of bridging rate (%) = ((G1-G2) / G2) × 100

[Experimental Example 5] (Extended Test)

The adhesives of the adhesive sheets obtained in the examples and comparative examples were laminated in several layers so that the total thickness was 600 μm, and then a sample having a width of 10 mm × a length of 75 mm was cut, and the measurement site of the sample was 10 mm × 20 mm in length. (Extending direction): Put the tensile tester (manufactured by ORIENTEC CO., LTD., Product name "TENSILON") on the above sample, and use the tensile tester under the environment of 23 ° C and 50% RH, at an extension speed of The elongation at break (%) was measured at 200 mm / min. In addition, the sample was stretched to the breaking elongation to measure its maximum stress (N). The results are shown in Table 2.

[Experimental Example 6] (Evaluation of Anti-Foaming Property)

The polyethylene terephthalate film (OIKE & CO) formed by inserting the adhesive layer of the adhesive sheet obtained in the examples and comparative examples into a transparent conductive film made of indium tin oxide (ITO) on one side. ., LTD., ITO film, thickness: 125 μm) Transparent conductive film, polycarbonate (PC) board (manufactured by MITSUBISH GAS CHEMICAL COMPANY, INC., Product name "IUPIRON‧SHEET MR58", thickness: 1mm), or acrylic made of polymethyl methacrylate (PMMA) Sheet (manufactured by MITSUBISH GAS CHEMICAL COMPANY, INC., Product name "IUPIRON‧SHEET MR200", thickness: 1 mm) to obtain a laminated body.

The obtained laminate was placed under the conditions of 50 ° C and 0.5Mpa, and subjected to autoclaving for 30 minutes, and then placed in normal pressure, 23 ° C, and 50% RH for 15 hours, and then under the durable conditions of 85 ° C and 85% RH. Keep for 72 hours. Afterwards, confirm with the naked eye whether there are air bubbles, floating, peeling, etc. in the adhesive layer.

The anti-foaming resistance was evaluated according to the following criteria, and the results are shown in Table 2.

◎ ... No bubbles, floating and peeling.

○ ... Only bubbles with a diameter of 0.1 mm or less were generated.

× ... Bubbles, floating, or peeling of more than 0.1 mm in diameter were generated.

[Experimental Example 7] (Evaluation of film strength)

The adhesives of the adhesive sheets obtained in the examples and comparative examples were laminated in several layers so that the total thickness became 1 mm, and then the product name was "SUPER CUTTER PN1-600" manufactured by a cutting equipment (OGINO SEISAKUSHO CO., LTD.). ) Cutting. After cutting, the cut surface (length: 100 mm) of the adhesive layer was visually confirmed, and the film strength was evaluated according to the following criteria.

○: No defect in the adhesive layer on the cut surface (high film strength)

×: Defective adhesive layer on the cut surface (low film strength)

[Experimental Example 8] (Evaluation of Trackability of Step Difference)

A glass plate (manufactured by NSG PRECISION, product name "CORNING Glass EAGLE XG", length 90 mm x width 50 mm x thickness 0.5 mm) is coated with a UV curable ink (TEIKOKU PRINTING INKS MFG.CO., LTD., Product name "POS-911SUMI") so that its thickness becomes one of 5 μm, 10 μm, 15 μm, and 20 μm, and screen printing is performed in a frame shape (outer shape: length 90 mm × width 50 mm, width 5 mm). Next, ultraviolet radiation was applied (80 W / cm ² , ^two metal halide lamps, a lamp height of 15 cm, and a belt speed of 10 to 15 m / minute). The printed ultraviolet curable ink was cured, and then produced by printing. The step (the height of the step: one of 5 μm, 10 μm, 15 μm, and 20 μm) is attached to a glass plate.

The light release type release sheet was unloaded from the adhesive sheets obtained in the examples and comparative examples, and the exposed adhesive layer was attached to a polyester film (manufactured by TOYOBO CO., LTD., A product name) containing an easily adhesive layer. "PET A4300", thickness: 100 μm). Then the unpeeled release sheet is unloaded to expose the adhesive layer. Then, using a plastic laminating machine (manufactured by FUJIPLA INC., Product name "LPD3214") to fully cover the peripheral printed surface of the adhesive layer, the glass plates between the steps of the laminated body were bonded as a whole. Evaluate test samples.

The obtained evaluation sample was placed under the conditions of 50 ° C. and 0.5 MPa, and subjected to autoclaving for 30 minutes, and then left at normal pressure, 23 ° C., and 50% RH for 24 hours. Next, after storing for 72 hours (durability test) under durability conditions of 85 ° C. and 85% RH, the step traceability was evaluated. The step difference traceability is to determine whether the printing step difference is completely filled through the adhesive layer. If a gap or a bubble is observed between the printing step difference and the interface of the adhesive layer, it is determined that the printing step difference cannot be tracked. The step tracking performance here is evaluated by the step tracking rate (%) shown in the following formula, and the results are shown in Table 2.

Segment tracking rate (%) = {(Segment height (μm) to maintain no void or bubble adhesion after durability test) / (thickness of adhesive layer: 50μm)} × 100

As shown in Table 2, the adhesive layer obtained in the examples has superior segment tracking and high film strength.

[Industrial availability]

The adhesive sheet of the present invention is suitable for, for example, the joining of a display body module and a protective plate with a step difference.

Claims (9)

An adhesive sheet is provided with an adhesive layer made of an adhesive and two release sheets, and the adhesive layer is sandwiched by the release sheet in a form in contact with the release surfaces of the two release sheets. The adhesive sheet is characterized in that the above-mentioned adhesive layer is an adhesive layer for adhering a display body constituting member having at least a bonding side surface with a step difference, and other display body constituting members. Agent for a (meth) acrylate polymer (A) containing a reactive functional monomer as a unit containing a polymer constituting monomer, a bifunctional or more active energy ray-curable component (B), The bridging bridging agent (C) is an adhesive composition which is cured by thermal bridging and active energy rays; the content of the active energy ray-curable component (B) in the adhesive composition is to make The bridging ratio (G1) of the adhesive and the bridging ratio of the adhesive obtained by applying a thermal bridge to an adhesive composition other than the active energy ray-curable component (B) in the adhesive composition (G2), which is substantially the same amount; in addition, the adhesive layer has a thickness of 600 μm and a width of In the case of 10mm, in a 23 ° C, 50% RH environment, with a measuring length of 20mm and an extension speed of 200mm / min, the maximum stress can reach 2.8N or more when extended to the breaking elongation. The adhesive sheet according to item 1 of the scope of patent application, wherein the bridging ratio (G1) is 40 to 80%. The adhesive sheet as described in item 1 of the scope of the patent application, where the adhesive layer is 600 μm thick and 10 mm wide, in an environment of 23 ° C and 50% RH, the length is 20 mm and the extension speed is 200 mm When extending per minute, the breaking elongation is more than 1000%. The pressure-sensitive adhesive sheet according to item 1 of the scope of patent application, wherein the weight average molecular weight of the (meth) acrylate polymer (A) is 200,000 to 1 million. The adhesive sheet according to item 1 of the scope of patent application, wherein the (meth) acrylate polymer (A), as a monomer unit constituting the polymer, contains the above-mentioned reactive functional group-containing monomer 5 to 30 quality%. The pressure-sensitive adhesive sheet according to item 1 of the scope of patent application, wherein the reactive functional group of the reactive functional group-containing monomer is a carboxyl group and / or a hydroxyl group, and the bridging agent (C) is an isocyanate bridging agent and / Or epoxy bridging agent. The adhesive sheet according to item 1 of the scope of patent application, wherein the thickness of the adhesive layer is 10 to 400 μm. A display body is a display body having a display body constituent material capable of stepping at least the bonding surface, other display body constituent materials, and an adhesive layer to which the display body constituent material and the other display body constituent material are adhered, It is characterized in that the above-mentioned adhesive layer is the adhesive layer of the adhesive sheet described in item 1 of the scope of patent application. The display body according to item 8 of the scope of patent application, wherein the above-mentioned step difference is a border pattern when viewed from a plane.