TW201623521A - Adhesive, adhesive sheet, and display element - Google Patents

Abstract

An adhesive for cementing together one display element constituent member having a step on the surface on the to-be-cemented side and another display element constituent member, wherein the adhesive is obtained by causing an adhesive composition to be thermally crosslinked and cured using active energy rays, said composition containing a (meth)acrylic ester polymer (A) that includes a reactive-functional-group-containing monomer as a monomer unit constituting a polymer, a bi- or higher-functional component (B) that can be cured using active energy rays, and a thermally crosslinkable crosslinking agent (C). The adhesive composition contains the active-energy-ray-curable component (B) in such an amount that the gel fraction (G1) of the adhesive and the gel fraction (G2) of the adhesive formed by thermally crosslinking the adhesive composition from which the active energy ray curable component (B) has been excluded are substantially the same, and, assuming that the adhesive is formed into a layer measuring 600 [mu]m in thickness and 10 mm in width, the maximum stress when the adhesive layer extends in length up to elongation at break at a measurement length of 20 mm and a tensioning rate of 200 mm/minute in a 23 DEG C, 50% RH environment is 2.8 N or more.

Description

Adhesive, adhesive sheet and display body

The present invention relates to a display for adhering an adhesive and a bonding sheet for a component of a display, and an adhesive layer using the bonding sheet.

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

As for the screen, a protective panel is usually installed on the surface side of the display body module, and a gap is formed between the protection panel and the display body module, so that the protective panel does not touch the display phantom even if it is deformed by an external force. group.

However, as described above, there is an air layer, which causes a difference in refractive index between the protective panel and the air layer, and a light reflection loss of a difference in refractive index between the air layer and the display module, and the refractive index is poor. The reflection loss of light becomes large, resulting in a problem of poor image quality of the display.

Therefore, the gap between the protective panel and the display body module is filled with an adhesive, and a proposal for optimizing the image quality of the display is derived. However, on the display module side of the protective panel, the border-shaped printed layer may be a step difference. If the adhesive layer does not track the step, the adhesive layer may float around the step, thus resulting in The reflection loss of light is such that the above-mentioned adhesive layer requires step tracking.

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

[Previous Technical Literature] [Patent Literature]

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

In Patent Document 1, when the adhesive layer is placed at a normal temperature, the storage modulus is low, so that the step tracking property must be improved. In addition, through other methods, it is also possible to reduce the bridging degree of the thermal bridge type of adhesive, that is, the bridging rate and improve the tracking of the step difference. However, in the same manner, if the storage elastic modulus or the bridging ratio is lowered, the film strength of the adhesive layer is lowered and the workability is also deteriorated. For example, when the adhesive sheet is separated and processed, the adhesive adheres to the blade surface and occurs. A part of the adhesive layer is defective.

The present invention has been accomplished in view of such circumstances. The object of the invention is to provide an adhesive and an adhesive sheet which are excellent in step-tracking property, 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 for providing a display body component having a step on which a surface on at least the bonding side is bonded. The material and the other components of the display body constitute a bonding agent. The above-mentioned adhesive is a (meth)acrylate polymer (A) containing a reactive functional group monomer in a unit containing a polymer-constituting monomer, and an active energy ray curability of two or more functional groups. The adhesive composition of the component (B) and the heat bridge bridging agent (C) is cured by a heat bridge and an active energy ray. The content of the active energy ray-curable component (B) in the adhesive composition is such that the bridging ratio (G1) of the adhesive and the active energy ray curability in the adhesive composition are removed. The bridging ratio (G2) of the adhesive obtained by applying the thermal bridging to the adhesive composition other than the component (B) 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 measured in a 23 ° C, 50% RH environment with a measurement length of 20 mm, an elongation speed of 200 mm/min, and elongation to breaking elongation. Up to 2.8N or more (Invention 1).

The adhesive according to the above invention (Invention 1) has excellent step traceability and high film strength if the above conditions are satisfied.

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

In the above invention (Inventions 1 and 2), when the thickness of the adhesive layer is 600 μm and the width is 10 mm, the breaking length at a length of 20 mm and an elongation speed of 200 mm/min is measured in an environment of 23° C. and 50% RH. A degree of more than 1000% is preferred (Invention 3).

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

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

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

Secondly, the present invention provides an adhesive sheet having an adhesive layer (Invention 7) using the above-mentioned adhesive (Inventions 1 to 6).

In the above invention (Invention 7), the thickness of the above-mentioned 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 in contact with the release surface of the two release sheets (Invention 9). .

According to a third aspect of the invention, there is provided a display body comprising: a display body constituent member capable of providing a step on at least the side of the bonding side, another display body constituent member, and the above-described one display member constituent member and the other display member constituent member; The display body of the adhesive layer. The adhesive layer is characterized in that the adhesive layer is the adhesive layer of the adhesive sheet (Inventions 7 to 9).

In the above invention (Invention 10), even when the step is viewed from a plane, a frame-like pattern can be exhibited (Invention 11).

The adhesive layer of the adhesive and the adhesive sheet of the invention has excellent step tracking property and high film strength. In the display body made of such a bonding sheet, the adhesive layer can track the step difference in the case of a step on the bonding side, and after the endurance condition, it is still difficult to generate a gap between the step and the adhesive or The bubble and the adhesive layer can maintain the step difference.

1‧‧‧bonding piece

11‧‧‧Adhesive layer

12a, 12b‧‧‧ peeling film

2‧‧‧Display

21‧‧‧1st display body component

22‧‧‧Second display body components

3‧‧‧Printing layer

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

(Fig. 2) A cross-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 the present embodiment is a binder that adheres to at least one of the display body members having a step on the side surface, and forms a bonding material with the other display members. The display body and the display body constituent member will be discussed later.

The adhesive according to the present embodiment is a (meth) acrylate polymer (A) containing a reactive functional group monomer as a monomer unit constituting a polymer, and is cured with a bifunctional or higher active energy ray. The adhesive component (B) and the heat-bridged bridging agent (C) adhesive composition (hereinafter referred to as "adhesive composition P") are cured by a heat bridge and an active energy ray. It is presumed that among such an 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 component (B) is polymerized and entangled. In the above three-dimensional mesh structure, the structure is hereinafter referred to as "structure X". Further, in the specification of the present invention, the term "(meth)acrylic acid" means all of acrylic acid and methacrylic acid, and other similar terms are also the same. In addition, in the "polymer", the concept of "copolymer" is also included.

The content of the active energy ray-curable component (B) of the above-mentioned adhesive composition P is such that the adhesive bridging ratio (G1) according to the embodiment and the activity from the adhesive composition P are removed. Viscosity of energy ray curable component (B) The bridging ratio (G2) of the adhesive formed after the thermal bridging of the bonding composition (hereinafter referred to as "adhesive H") is actually the same. In addition, the term "actually the same" as used herein refers to a level in which the rate of change in the bridging rate which occurs later is 15% or less.

The adhesion rate change rate is the adhesion ratio of the adhesive agent bridging ratio G1 (%) according to the present embodiment, and the adhesive composition of the active energy ray-curable component (B) is excluded from the self-adhesive composition P. When the bridging ratio of the adhesive H formed by the heat bridge is G2 (%), it can be expressed by the following formula.

Bridging rate change rate (%) = {(G1-G2) / G2} × 100

In the adhesive according to the embodiment, the rate of change in the bridging ratio is preferably 0 to 15%, more preferably 0 to 10%, and particularly preferably 0 to 4%. In addition, the measurement method of the bridging rate is the same as the experimental example which will be described later.

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

In the adhesive according to the embodiment, the adhesive composition P containing the active energy ray-curable component (B) in the above amount is thermally bridged. It is presumed that it is formed in the three-dimensional network structure formed by the (meth) acrylate polymer (A) and the bridging agent (C), and is entangled with the polymerized active energy ray to the extent that the bridging rate does not substantially change. Structure X of the curable component (B). According to such a configuration X, the adhesive according to the present embodiment exhibits excellent stress relaxation properties and excellent step tracking property. Therefore, when the display body is a member having a step on the bonding surface and is bonded to another display member, the adhesive according to the embodiment can satisfactorily track the step, and the step and adhesion are set after the endurance condition is set. It is still difficult to generate voids or bubbles between the agents, and the adhesive layer can maintain the state in which the step is full (hereinafter, the step tracking property after setting the endurance condition is simply referred to as "step difference tracking property"). Further, according to the above configuration X, the adhesive according to the present embodiment exhibits high film strength. Therefore, for example, when the bonding sheet is punched, the adhesive can be prevented from adhering to the blade surface, and the adhesive is generated. There is a partial defect in the layer.

(1) (meth) acrylate polymer (A)

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

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

Hydroxy-containing monomer, for example: 2-hydroxyethyl (meth) acrylate, (A 2-hydroxypropyl acrylate, 3-hydroxypropyl (meth)acrylate, butyl 2-hydroxyethyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, (meth)acrylic acid 4 a hydroxyalkyl (meth) acrylate such as hydroxybutyl. Among them, in the obtained (meth) acrylate polymer (A), 2-hydroxyethyl (methyl) is seen from the reactivity with the hydroxyl group-trapping agent (C) and the copolymerizability of other monomers. Acrylate or 4-hydroxybutyl (meth)acrylate is preferred. These may be used alone or in combination of two or more.

a carboxyl group-containing monomer, for example, an ethylenically unsaturated carboxylic acid such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, citraconic acid or the like, wherein the obtained (meth) acrylate polymer ( In A), acrylic acid is preferred from the viewpoint of reactivity with a bridging agent (C) of a hydroxyl group and copolymerizability of other monomers. These may be used alone or in combination of two or more.

The amino group-containing monomer may, for example, be ethyl (meth)aminoacrylate or ethyl (meth)-n-butylaminoacrylate. These may be used alone or in combination of two or more.

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

The (meth) acrylate polymer (A), as the reactive functional group-containing monomer constituting the polymer, preferably contains 10 to 25% by mass, more preferably, in the case of containing a hydroxy group-containing monomer. 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 thereof is preferably 8 to 25% by mass, more preferably 10 to 15% by mass. %.

The (meth) acrylate polymer (A) is preferably a monomer unit constituting the polymer, and an alkyl (meth) acrylate having 1 to 20 carbon atoms in the alkyl group is preferably produced. The adhesive has good adhesion. Further, among the alkyl (meth)acrylates, the hard monomers described later are excluded.

The alkyl (meth)acrylic acid having 1 to 20 carbon atoms of the alkyl group, for example, methyl acrylate, ethyl acrylate, (meth) acrylate propane, propyl (meth) acrylate, (A) Base) n-butyl acrylate, (meth) acrylate n-pentyl, (meth) acrylate n-hexyl, (ethyl) acrylate 2-ethylhexyl, (meth) acrylate isooctyl, (methyl ) n-decyl acrylate, (meth) acrylate n-dodecyl, (meth) acrylate nutmeg, (meth) acrylate palm, (meth) acrylate hard fat, and the like. Among them, from the viewpoint of further improving the adhesion, it is preferred that the alkyl group has a (meth) acrylate having 1 to 8 carbon atoms, more preferably n-butyl (meth) acrylate and (meth) acrylate. 2-ethylhexyl. These may be used alone or in combination of two or more.

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

When the display body is subjected to high temperature and high humidity, bubbles may be generated in the vicinity of the step position, or abnormal blistering such as bubbles, floating, and peeling may occur when the plastic sheet of the protective panel is exhausted. In this regard, as (meth) propyl The polymer monomer unit composed of the olefin polymer (A) preferably contains a hard monomer having a glass transition temperature (Tg) of 70 ° C or higher. If the above-mentioned hard monomer is contained in the polymer unit composed of the (meth) acrylate polymer (A), the cohesive force of the produced adhesive will be improved, and the anti-foaming property for use on the display body will be improved. Also better. In particular, in the monomer unit composed of the (meth) acrylate polymer (A), the glass transition temperature (Tg) of a homopolymer such as 2-ethylhexyl (meth)acrylate is lower (for example, When Tg is preferably -30 ° C or less, and more preferably -60 ° C or less, as a main component, since the cohesive force tends to decrease, it is preferred to use the above-mentioned hard monomer. The glass transition temperature (Tg) of the above hard monomer as a homopolymer is preferably 75 to 200 ° C, particularly preferably 80 to 180 ° C. Further, when a carboxyl group-containing monomer is used as the reactive functional group-containing monomer of the (meth) acrylate polymer (A), a certain degree of cohesive force can be obtained by permeating the monomer. Therefore, in this case, the above hard monomers are less frequently used.

Examples of the hard monomer include methyl methacrylate (Tg 105 ° C), isobornyl acrylic acid (Tg 94 ° C), isobornyl ester (Tg 180 ° C), propylene morpholine (Tg 145 ° C), and diamond acrylate (Tg 115 ° C). Amantadine (Tg 141 ° C), dimethyl methacrylate (Tg 89 ° C), acrylamide (Tg 165 ° C) and the like. These may be used alone or in combination of two or more.

Among the above hard monomers, methyl methacrylate, isobornyl acrylate and the like, from the viewpoint of preventing adverse effects on other properties such as adhesion and transparency, and allowing hard monomers to exhibit better performance. Propylene morpholine is preferred; acrylic isobornyl acrylate and propylene morpholine are preferred from the viewpoint of less traceability of the step difference.

(meth) acrylate polymer (A) as a constituent of the polymer The monomer unit preferably contains the hard monomer in an amount of 10 to 45% by mass, more preferably 15 to 30% by mass. When the hard monomer is contained in an amount of 10% by mass or more, the effect of improving the foaming resistance can be obtained by passing through the monomer unit. On the other hand, when the content of the hard monomer is 45% by mass or less, it is possible to prevent the relative shortage of the other monomer units other than the (meth) acrylate polymer (A), and to produce a viscosity. Adhesives with good adhesion and followability.

The (meth) acrylate polymer (A) may contain other monomers as a monomer unit constituting the polymer, if necessary. For the other monomers, it is preferred to use a functional group-free monomer which does not interfere with the action of the reactive functional group-containing monomer. Examples of such a monomer include a (meth)acrylic acid methoxyethyl group, a (meth) acrylate ethoxyethyl group and the like (meth)acrylic acid alkoxyalkyl ester, and a (meth) ring. Non-bridging property of alicyclic (meth) acrylate such as hexyl acrylate, N,N-dimethylaminoethyl (meth) acrylate, N,N-dimethylaminopropyl (meth) acrylate, etc. Grade 3 amino (meth) acrylate, vinyl acetate, styrene, and the like. These may 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 from 200,000 to 1,000,000, more preferably from 300,000 to 900,000, and particularly preferably from 400,000 to 700,000. Further, 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 above, and when it is in a lower range, the traceability can be excellent through the step difference. Show the adhesive. When the weight average molecular weight of the (meth) acrylate polymer (A) exceeds 1,000,000, the tracking property of the step is deteriorated. On the other hand, if the weight average molecular weight of the (meth) acrylate polymer (A) is less than 200,000 will cause the durability of the adhesive to deteriorate.

Further, in the adhesive composition P, the (meth) acrylate polymer (A) may be used singly or in combination of two or more.

(2) Active energy ray curable component (B)

When the adhesive composition P is in the above-described compounding amount, the active energy ray-curable component (B) containing two or more functional groups is used, and the adhesive composition P is cured, and the adhesive is produced not only It has excellent step tracking and high film strength.

The active energy ray-curable component (B) is not particularly limited as long as it does not impair the effects of the present invention and is cured under irradiation with an active energy ray, and any of a monomer, an oligomer, and a polymer may be used. A mixture of ingredients is also good. Among them, a polyfunctional acrylate monomer having a molecular weight of less than 1,000, which is superior in compatibility with the (meth) acrylate polymer (A), is preferable.

The polyfunctional acrylate monomer having a molecular weight of less than 1,000 may, for example, be 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol II. (Meth) acrylate, polyethylene glycol di(meth) acrylate, neopentyl glycol ester (meth) acrylate, hydroxypivalic acid neopentyl glycol di(meth) acrylate, dicyclopentane Di(meth)acrylate, caprolactone modified dicyclopentenyl di(meth)acrylate, ethylene oxide modified di(meth)acrylate, bis(propyleneoxyethyl) Isocyanurate, allylated cyclohexyl di(meth) acrylate, ethoxylated bisphenol A diacrylate, 9,9- Bis[4-(2-propenyloxyethoxy)phenyl]difunctional hydrazine; 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(propylene decyloxyethyl) Trifunctional type such as cyanurate, caprolactone ε-modified tris-(2-(methyl) propylene oxyethyl) isocyanurate; diglycerin tetra(meth) acrylate, pentaerythritol IV 4-functional form such as (meth) acrylate; 5-functional type such as propionic acid-modified dipentaerythritol penta (meth) acrylate; dipentaerythritol hexa(meth) acrylate, caprolactone-modified dipentaerythritol hexa(methyl) ) A hexafunctional type such as acrylate. These may be used alone or in combination of two or more.

As the active energy ray-curable component (B), an active energy ray-curable acrylate oligomer may be used, and the acrylate oligomer preferably has a weight average molecular weight of 50,000 or less. Examples of such acrylate oligomers include polyester acrylate, epoxy acrylate, urethane acrylate, polyether acrylate, polybutadiene acrylate, decane acrylate, and the like.

The weight average molecular weight of the above 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 may be used singly or in combination of two or more.

Further, as the active energy ray-curable component (B), an adduct acrylate 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 copolymerizing a (meth) acrylate group with a copolymer of a (meth) acrylate and a monomer having a bridging functional group in the molecule. The compound of the bridging functional group-reactive group is obtained by reacting a part of the bridging functional group of the copolymer.

The weight average molecular weight of the above-mentioned adduct acrylate polymer is preferably from 50,000 to 900,000, more preferably from about 100,000 to 500,000.

The active energy ray-curable component (B) may be selected from the above-mentioned polyfunctional acrylate monomer, acrylate oligomer, and adduct acrylate polymer, or may be used in combination of two or more types. The active energy ray-curable component other than the above components is used.

The content of the active energy ray-curable component (B) in the adhesive composition P is as described above, but 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 part by mass or more, more preferably 0.5 part 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 the present embodiment, heat is applied to the adhesive composition excluding the active energy ray-curable component (B) in the adhesive composition P. By bridging, the bridging ratio (G2) of the produced adhesive H is actually made uniform, and the content of the active energy ray-curable component (B) is obtained from the viewpoint of obtaining superior step-tracking property. When the 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, more 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 passes through the heated bridge (meth) acrylate polymer (A) to form a three-dimensional network structure, thereby improving the cohesive force of the produced adhesive. And impart durability to the adhesive.

The above bridging agent (C), as long as it can be polymerized with (meth) acrylate The reactive functional group of the compound (A) may be reacted, for example, an isocyanate bridging agent, an epoxy resin bridging agent, an amine bridging agent, a melamine bridging agent, an aziridine bridging agent, an anthracene bridging agent, an aldehyde system. 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 hydroxy, it is preferred to use an isocyanate bridging agent excellent in reactivity with hydroxy; if (meth) acrylate polymer (A) When the reactive functional group is a carboxyl group, an epoxy resin bridging agent excellent in reactivity with a carboxyl group is preferably used. Further, the bridging agent (C) may be used singly or in combination of two or more.

The isocyanate bridging agent must contain an isocyanate compound. The isocyanate compound may, for example, be an aromatic polyisocyanate such as diisocyanate, diphenylmethane diisocyanate or cyanate; an aliphatic polyisocyanate such as hexamethylene diisocyanate, isophorone diisocyanate or hydrogenated diphenyl An alicyclic polyisocyanate such as methane diisocyanate, a urethane ureide, an isocyanurate, and a low molecular weight active hydrogen such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane or castor oil The reactant adduct of the compound, and the like. Among them, trimethylolpropane-modified aromatic polyisocyanate, particularly trimethylolpropane-modified toluene diisocyanate, modified with trimethylolpropane, from the viewpoint of reactivity with hydroxyl groups Cyanate esters are especially preferred.

Examples of epoxy resin bridging agents are: 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 bridging agent (C) content in the adhesive composition P is preferably 0.001 to 2 by mass when the (meth) acrylate polymer (A) is 100 parts by mass. It is preferably 0.01 to 1 part by mass, and more preferably 0.02 to 0.3 parts by mass. When the content of the bridging agent (C) is 0.001 part by mass or more, the durability of the produced adhesive can be improved, and when the content of the bridging agent (C) is 2 parts by mass or less, the bridge can be appropriately bridged to ensure the The resulting adhesive has a step traceability.

(4) Various additives

For the adhesive composition P, various additives commonly used for the acrylic adhesive can be used as needed. For example: decane coupling agent, photopolymerization initiator, antistatic agent, tackifier, antioxidant, ultraviolet absorber, light stabilizer, softener, filler, refractive index modifier, and the like.

The decane coupling agent is preferably an organic ruthenium compound having at least one alkoxyalkylene group in the molecule and having good compatibility with the (meth) acrylate polymer (A). Further, when the adhesive is used for optical use, a light-transmitting decane coupling agent is preferred.

Such a decane coupling agent can be exemplified by vinyl trimethyl, vinyl triethoxy decane, methacryl oxime or the like containing a polymerizable unsaturated hydrazine compound, 3-glycidoxypropyl group, 2-(3, 4). - anthracene compound having epoxy resin structure such as epoxycyclohexyl)ethyltrimethyl, 3-mercaptopropyltrimethoxydecane, 3-mercaptopropyltriethoxydecane, 3-mercaptopropyldimethoxymethyl Anthracene-based fluorene-containing compound such as decane or the like, 3-aminopropyl, N-(2-aminoethyl)-3-aminopropyl, N-(2-aminoethyl)-3-aminopropylmethyldimethoxy An aminoguanidine-containing compound such as decane or the like, 3-chloropropyltrimethoxydecane, 3-isocyanatepropyltriethoxydecane, or at least one of them and methyltriethoxydecane, methyltriethoxydecane, An alkyl-containing hydrazine compound such as ethyltriethoxydecane, methyltrimethoxydecane or ethyltrimethyl, and a concentrate thereof. The above components may be used singly or in combination of two or more.

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

Further, as the active energy ray for irradiating the adhesive composition P, when the ultraviolet ray is used, the adhesive composition P preferably 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 irradiation amount of the active energy ray can be reduced.

Such a photopolymerization initiator can be exemplified by benzoin, benzoin methyl ether, benzoin ethyl 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-propan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholine-propan-1 -ketone, 4-(2-hydroxyethoxy)phenyl-2-(hydroxy-2-propyl)one, benzophenone, p-phenylbenzophenone, 4,4'-diethyl Aminobenzophenone, dichlorobenzophenone, 2-methyloxime, 2-ethylhydrazine, 2-tert-butylhydrazine, 2-aminopurine, 2-methylthioxanthone, 2-ethyl thioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzoin dimethyl ketal, acetophenone II Methyl ketal, p-dimethylaminobenzoate, oligo[2-hydroxy-2-methyl-1[4-(1-methylvinyl)phenyl]propanone], 2,4, 6-Trimethylbenzimidyl-diphenyl-phosphine oxide, and the like. The above components may be used singly or in combination of two or more.

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

(5) Manufacture of adhesive composition

The adhesive composition P can pass through the (meth) acrylate polymer (A) to produce the (meth) acrylate polymer (A) and the active energy ray-curable component (B), and the bridging agent (C) After mixing, add additives as needed.

The (meth) acrylate polymer (A) can be polymerized by a general free radical polymerization method through a monomer mixture constituting the polymer, and the polymerization of the (meth) acrylate polymer (A) can be used according to requirements. The polymerization initiator was applied to a solution polymerization method. The polymerization solvent may, for example, be ethyl acetate, n-butyl acetate, isobutyl acetate, toluene, acetone, hexane or methyl ethyl ketone, and may be used in combination of two or more kinds.

The polymerization initiator may, for example, be an azo compound or an organic peroxide, and may be used in combination of two or more kinds. The azo compound can be exemplified by 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), two Methyl 2,2'-azobis(2-methylpropionate), 4,4'-azobis(4-cyanovaleric acid), 2,2'-azobis(2-hydroxyl) Alkylpropionitrile), 2,2'-azobis[2-(2-imidazolin-2-yl)propane], and the like.

Examples of the organic peroxides include benzammonium peroxide, t-butyl perbenzoate, cumene hydroperoxide, diisopropyl peroxydicarbonate, and di-N-propyl peroxydi(2-) Ethoxyethyl)peroxydicarbonate, tert-butylperoxy neosodium, tert-butylperoxidation, (3,5,5-trimethylhexyl) peroxide, dipropyl fluorenyl auxiliary Oxide, diethyl hydrazine peroxide, and the like.

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

If the (meth) acrylate polymer (A) is produced, the active energy ray-curable component (B) is added to the (meth) acrylate polymer (A) solvent, and the bridge is bridged. The agent (C), and the additive are added as needed, and the adhesive composition P can be obtained after thorough mixing.

(6) Manufacture of adhesives

The above-mentioned adhesive composition P is applied to a reference material as required, and then thermally bridged, and cured by active energy rays (active energy ray curing) to obtain an adhesive according to the present embodiment. .

The heat bridge of the adhesive composition P can be carried out by heat treatment, and this heat treatment can also be carried out simultaneously after the application of the adhesive composition P in the drying process. The preferred heating temperature for the heat treatment is 50 to 150 ° C, more preferably 70 to 120 ° C. Further, the preferred heating time is from 10 seconds to 10 minutes, more preferably from 50 seconds to 2 minutes.

Here, the active energy ray means that there is an energy quantum in an electromagnetic wave or a charged particle beam, and in detail, an ultraviolet ray or an electron beam can be exemplified. Among the active energy rays, ultraviolet rays which are easy to handle are particularly preferable.

A high-pressure mercury lamp, a Fusion H lamp, a xenon lamp, or the like can be used for the ultraviolet irradiation, and the ultraviolet irradiation amount is preferably 50 to 1000 mW/cm ² . Further, the preferred amount of light is from about 50 to 10,000 mJ/cm ² , more preferably from 80 to 5,000 mJ/cm ² , and particularly preferably from 200 to 2,000 mJ/cm ² . On the other hand, an electron beam accelerator or the like can be used for the electron beam irradiation, and the irradiation amount of the electron beam is preferably about 10 to 1000 krad.

When the adhesive composition P is heat-treated, the (meth) acrylate polymer (A) reacts with the bridging agent (C) to form a bridge structure-stereoscopic network structure. Further, when the active energy ray is applied to the adhesive composition P, the active energy ray-curable component is polymerized (B) and entangled while being entangled in the three-dimensional network structure. In this way, the resulting bond of the embodiment is The agent has superior step tracking and high film strength.

Further, when the adhesive according to the present embodiment is produced, the active energy ray may be irradiated after the heat treatment, or both treatment methods may be simultaneously performed. Further, after the heat treatment or after the irradiation of the active energy ray, it is placed at a normal temperature (for example, 23 ° C, 50% RH), and the curing period of about 1 to 2 weeks is preferably maintained.

(7) Bridging rate

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

(8) Breaking elongation

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

The adhesive according to the present embodiment is obtained by heat-bonding the above-mentioned adhesive composition P to the active energy ray to achieve the above-described breaking elongation. When the breaking elongation is as high as described above, the step tracking property of the adhesive becomes superior.

(9) Parallel tracking rate

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

Segment tracking rate (%) = {(without gap test or bubble adhesion after setting endurance test The height of the step (μm) maintained by the state / (thickness of the adhesive layer)} × 100

Further, the test method of the step tracking rate is the same as the experimental example which will be described later.

The adhesive according to the present embodiment is obtained by heat-bonding the above-mentioned adhesive composition P to the active energy ray to achieve the large-section tracking rate as described above.

[bonding sheet]

As shown in Fig. 1, the adhesive sheet 1 according to the present embodiment is composed of two release sheets 12a and 12b and two release sheets 12a for bonding the release surfaces of the two release sheets 12a and 12b. The adhesive layer 11 is embedded between 12b. Further, the release surface of the release sheet in the specification of the present invention refers to a surface having peeling property in the release sheet, and the surface subjected to the release treatment and the surface having the release property without peeling treatment are included.

(1) adhesive layer

The adhesive layer 11 of the adhesive sheet 1 is composed of the above-mentioned adhesive, that is, after the adhesive composition P is thermally bridged and the active energy ray is cured, and the obtained adhesive is used.

The thickness of the adhesive layer 11 (a value measured based on JIS K7130) is preferably 10 to 1000 μm, preferably 30 to 400 μm, more preferably 50 to 300 μm. Further, 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 property may not be obtained. On the other hand, when the thickness of the adhesive layer 11 is 1000 μm or less, it has good workability.

(2) peeling 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 a polyethylene terephthalate. Film, polynaphthalene film, polyethylene terephthalate film, polyurethane film, ethylene vinyl acetate film, ionomer resin film, ethylene (meth)acrylic copolymer film, ethylene-(meth)acrylate copolymerization As the material film, the polystyrene film, the polycarbonate film, the polyimide film, the fluororesin film, or the like, a bridge film of the above film may be used, or a laminate film of the above film may be used.

The release surface of the release sheets 12a and 12b (particularly the surface in contact with the adhesive layer 11) is preferably subjected to a release treatment. Examples of the release agent used in the release treatment include alkyd, anthrone, fluorine, unsaturated polyester, polyolefin, and wax release agent. Further, the release sheet on one side 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) Manufacture of adhesive sheets

As a manufacturing example of the adhesive sheet 1, the coating liquid of the adhesive composition P is applied onto the peeling surface of the one side 12a (or 12b) of the release sheet, and then the coating layer is heat-treated. The adhesive composition P is irradiated with an active energy ray while thermally bridging, and the adhesive composition P is cured to form the adhesive layer 11. On the other side of the formed adhesive layer 11, the peeling faces of the release sheet 12b (or 12a) overlap each other to serve as the adhesive sheet 1. Further, the 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 other side release sheet 12b (or 12a) is overlapped on the coating layer. get on.

As another manufacturing example of the adhesive sheet 1, the coating liquid of the above-mentioned adhesive composition P is applied to the peeling surface of the one side release sheet 12a, and 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 the first adhesive layer. Then, the coating liquid of the adhesive composition P is applied to the peeling surface of the other side release sheet 12b, and the coating layer is heat-treated to irradiate the active energy ray while the adhesive composition P is thermally bridged to make the adhesive. The bonding composition P is cured to form a second adhesive layer. Next, the release sheet 12a to which the first adhesive layer is attached and the release sheet 12b to which the second adhesive layer adheres, and the two adhesive layers are bonded to each other to form the adhesive sheet 1. Further, instead of forming the first adhesive layer and the second adhesive layer separately, the adhesive sheet 1 is obtained, and when the respective coating layers are processed to the thermal bridging stage, they are brought into contact with each other. The active sheet is irradiated to obtain the adhesive sheet 1.

The method of applying the coating liquid of the above-mentioned adhesive composition P can be applied, for example, by a bar coating method, a knife coating method, a roll coating method, a plate coating method, a die coating method, a gravure coating method, or the like. The heat treatment conditions of the adhesive composition P are the same as described above.

In the above-mentioned adhesive sheet 1, since the adhesion layer 11 has excellent step tracking property, it is not easy to adhere to the step and the adhesive layer even after being in a set endurance condition after being adhered to the display body having a step. A void or a bubble is generated between the 11 and the adhesive layer 11 can fill the step. Further, since the film strength of the adhesive layer 11 is high, for example, when the bonding sheet 1 is punched, the adhesive agent adheres to the blade surface, and the adhesive layer 11 is partially defective.

(4) Haze value

Haze value of the adhesive layer 11 according to the present embodiment (by JIS) The value measured by K7136:2000 is 3% or less, preferably 2% or less, more preferably 1% or less. When the haze is 3% or less, it has a relatively high transparency and is suitable for optical use.

(5) Adhesion

Since the adhesive sheet 1 of the present embodiment can exhibit superior step tracking performance after the endurance condition, the adhesive strength (a value measured based on JIS Z0237:2009) is preferably 5 N/25 mm or more, and more preferably 10 N. /25mm or more, especially good for 25N/25mm or more. Further, 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. In addition, the detailed experimental example of the adhesion test method is the same as the description.

[display body]

As shown in FIG. 2, in the display body 2 according to the present embodiment, the first display body member 21 (one type of display body constituent member) and the second display body constituent member 22 (other display) are bonded to at least the side mask step. The body constituent member) and the adhesive layer 11 for bonding the first display member constituent member 21 and the second display member member member 22 are bonded to each other. In the display 2 according to the present embodiment, the first display constituent member 21 has a step on the surface on the side of the adhesive layer 11, and in detail, the printed layer 3 has a step.

The display body 2 can be exemplified by a liquid crystal (LCD) display, a light emitting diode (LED) display, an organic light emitting diode (organic EL) display, electronic paper, etc., and a touch panel is also preferable.

In addition to the glass plate or the plastic plate, the first display body constituent member 21 is preferably made of a laminate including the two or the like. In this case, generally, the printed layer 3 is formed on the first display body. The adhesive layer constituting the member 21 11 sides form a border pattern.

The second display body forming member 22 is a display body module (for example, a liquid crystal (LCD) module, a light emitting diode (LED) module, an organic light emitting diode (organic EL) module, etc.) or a part thereof (for example) : 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, yttrium-containing glass, glass aluminate, lead glass, borosilicate glass, and bismuth borate glass. Wait. Although the thickness of the glass plate is not particularly limited, it is generally 0.1 to 5 mm, preferably 0.2 to 2 mm.

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

In addition, the above-mentioned glass plate and plastic plate may be provided with various functional layers (transparent conductive film, metal layer, cerium oxide layer, hard plating layer, anti-glare layer, etc.) on one or both sides, or laminated optical components, transparent conductive The film and metal layer can also be patterned.

The optical member can be exemplified by a polarizing plate (polarizing film), a polarizing plate, a phase difference plate (retardation film), a viewing angle compensation film, a brightness enhancement film, a contrast enhancement film, a liquid crystal polymer film, a diffusion film, a hard plating film, and a half. Transmit a semi-reflective film or the like.

The material constituting the printed layer 3 is not particularly limited, and a known material may be used. The thickness of the printed 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, the adhesive sheet is first used. 1 is cut according to the corresponding size of the first display body constituent member 21 and the second display member constituent member 22. When cutting, the thickness direction of the adhesive sheet 1 can be completely cut off, or the other side of the adhesive sheet 1 can be not cut off. 12b, the adhesive layer 11 is half-cut with the one side release sheet 12a. At this time, since the film strength of the adhesive layer 11 is high, the problem that a part of the adhesive layer 11 is broken due to adhesion of the adhesive can be suppressed.

Then, after the one side release sheet 12a of the adhesive sheet 1 is peeled off, the exposed adhesive layer 11 of the adhesive sheet 1 is bonded to the surface on the side where the printed layer 3 of the first display body constituent member 21 is present, and then self-adhesive. The adhesive side 11 of the tab 1 peels off the other peeling sheet 12b, and the exposed adhesive layer 11 of the adhesive sheet 1 and the second display body constitute the member 22.

In the above-described process, when the adhesive layer 11 and the first display body are combined to form the member 21, since the adhesive layer 11 has excellent step tracking property, it is difficult to form the printed layer 3 even after setting the endurance condition. A gap is formed between the step formed and the adhesive layer 11, and the adhesive layer 11 can fill the step.

The embodiments described above are described in order to facilitate the understanding of the present invention, and the scope of the present invention is not limited thereto. Therefore, all design changes or equivalents within the technical scope of each element described in the above embodiments are still within the scope of the present invention.

For example, one of the peeling sheets 12a and 12b of the adhesive sheet 1 may be omitted, and the first display member 21 may have a step other than the printed layer 3 or may have no step. Further, not only the first display body constituent member 21 but also the second display body constituent member 22 are preferably provided when the adhesive layer 11 has a step.

[Examples]

Hereinafter, the present invention will be more specifically described by way of examples and the like, but The scope of the invention is not limited to the embodiments.

[Example 1]

1. Modulation of (meth) acrylate polymer

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 the (meth) acrylate polymer (A) was measured by a method described later. The weight average molecular weight (Mw) is 400,000.

2. Modulation of adhesive composition

100 parts by mass of the (meth) acrylate polymer (A) obtained in the above process (based on the solid content; the same applies hereinafter), and the tris(propylene oxyethyl) of the active energy ray-curable component (B) Cyanurate (manufactured by TOAGOSEI CO., LTD., product name "M-315") 0.1 parts by mass, epoxy resin bridging agent (C) 1,3-di(N,N-diglycidylamino 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-glycidoxypropane as a decane coupling agent 0.2 parts by mass of a base (manufactured by SHIN-ETSU CHEMICAL CO., LTD., product name "KBM-403"), and added 1-hydroxycyclohexyl phenyl ketone as a photopolymerization initiator (product name, manufactured by BASF Corporation) "IRGACURE 184") was added in an amount of 10% by mass based on the component (B), and after sufficiently stirring, it was diluted with methyl ethyl ketone to obtain a coating composition for a tackifying composition having a solid content concentration of 37% by mass.

The formulation of the adhesive composition is shown in Table 1. In addition, the details of the code number shown 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: Isobutyl acrylate

ACMO: propylene morpholine

VAc: vinyl acetate

[Active energy ray curable component]

M-315: tris(propylene decyl ethoxy) 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. Manufacture of adhesive sheets

A peeling-treated surface of a heavy-peelable release sheet (manufactured by LINTEC CORPORATION, product name "SP-PET752150") which has been subjected to a release treatment of a polyethylene terephthalate film by a non-silicone release film. The coating solvent of the adhesive composition is applied thereto by a knife coater. Further, after the coating layer was heat-treated at 100 ° C for 2 minutes, ultraviolet rays were irradiated 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

‧Light quantity: 500mJ/cm ²

‧ Illuminance: 200mW/cm ²

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

Similarly, on the one side of the polyethylene terephthalate film, the peeling-treated surface of the light-peelable release sheet (manufactured by LINTEC CORPORATION, product name "SP-PET382120") which has been subjected to the release treatment of the alumite release agent, The coating solvent of the obtained adhesive composition was applied thereto by a knife coater. Further, after the coating layer was heat-treated at 100 ° C for 2 minutes, ultraviolet rays were irradiated under the same conditions as described above to form a second adhesive layer having a thickness of 25 μm.

a heavy release type release sheet to which the first adhesive layer obtained as described above adheres, and a light release type release sheet to which the second adhesive layer obtained as described above adheres, The two adhesive layers were bonded to each other to form a bonded sheet of a heavy release type release sheet/adhesive layer (thickness: 50 μm)/light release type release sheet structure. In addition, the thickness of the adhesive layer is a value measured by a constant pressure thickness measuring instrument (product name "PG-02", manufactured by TECLOCK CORPORATION) based on JIS K7130.

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

The ratio of each monomer constituting the (meth) acrylate polymer (A), the weight average molecular weight of the (meth) acrylate polymer (A), the type and amount of the active energy ray-curable component (B), and the amount of the bridge The type and amount of the agent (C) and the amount of the decane coupling agent were as shown in Table 1, except that the changed portions were prepared in the same manner as in Example 1. Further, Comparative Examples 1 and 4 were not subjected to ultraviolet irradiation treatment.

The weight average molecular weight (Mw) is converted into polystyrene by a 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): TOSOH CORPORATION

TSK guard column HXL-H

TSK gel GMHXL (×2)

TSK gel G2000HXL

‧Measure solvent: tetrahydrofuran

‧Measurement temperature: 40 ° C

[Experimental Example 1] (Measurement of adhesion)

The adhesive sheet unloading light peeling peeling obtained in the examples and the comparative examples The adhesive layer of the exposed adhesive layer is adhered to an easy-bonding layer of a polyethylene terephthalate film (TOYOBO CO., LTD., PET A4300, thickness: 100 μm) having an easy-adhesion layer. The laminated body was cut into a size of 25 mm in width and 100 mm in length, and this was taken as a sample. After the heavy peeling release sheet was unloaded on the sample, soda lime glass (manufactured by NIPPON SHEET GLASS CO., LTD.) was adhered to the exposed adhesive layer.

Thereafter, it was allowed to stand under the conditions of a normal pressure of 23 ° C and 50% RH for 24 hours, and a tensile tester (ORIENTEC) was used as a test condition using a peeling speed of 300 mm/min and a peeling angle of 180° as a test standard based on JIS Z0237:2009. CO., LTD., product name "TENSILON") Test adhesion (N/25mm). The results are shown in Table 2.

[Experimental Example 2] (Measurement of haze value)

The adhesive layer of the adhesive sheet obtained in the examples and the comparative examples was a haze meter (manufactured by NIPPON DENSHOKU INDUSTRIES CO., LTD., product name "NDH-2000" based on JIS K7361-1:1997. Test the haze value (%). The results are shown in Table 2.

[Experimental Example 3] (Measurement of bridging rate)

The adhesive sheet obtained from the examples and the comparative examples was cut into 80 mm×80 mm, and the adhesive layer was coated in a polyester (PE) mesh (mesh size 200), and placed in a precision balance measuring quality; The quality of the above net can be calculated as the net mass of the adhesive, and the mass is M1.

Next, the above-mentioned adhesive coated in the polyester mesh was placed 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%. After air drying for 24 hours, it was placed in an oven and dried at 80 ° C for 12 hours. After drying, the mass is measured with a precision balance. The net mass of the adhesive can be calculated by subtracting the quality of the above net. Its quality is M2. The bridging rate (G1; %) is represented by (M2/M1) × 100. The results are shown in Table 2.

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

In the examples and the comparative examples, the adhesive composition was produced in the same manner as above except that the active energy ray-curable component (B) was not added. Next, using the adhesive composition, an adhesive sheet was produced in the same manner as described above except that the treatment was not carried out by ultraviolet irradiation. For the adhesive layer of the obtained adhesive sheet, the bridging ratio (G2; %) was measured in the same manner as in Experimental Example 3. This bridging rate is taken as G2. When the bridging ratio measured in Experimental Example 3 is taken as G1, the bridging rate change rate (%) exhibited by the following formula can be calculated, and the results are shown in Table 2.

Bridging rate change rate (%) = {(G1-G2) / G2} × 100

[Experimental Example 5] (Extension Test)

The adhesive layers of the adhesive sheets obtained in the examples and the comparative examples were laminated to have a total thickness of 600 μm, and then cut into a sample having a width of 10 mm and a length of 75 mm, so that the sample measuring portion was 10 mm in width × 20 mm in length. (stretching direction), a tensile tester (manufactured by ORIENTEC CO., LTD., product name "TENSILON") placed in the above sample, and using the tensile tester at 23 ° C, 50% RH, at an extension speed of The breaking elongation (%) 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 adhesive layer of the adhesive sheet obtained in the examples and the comparative examples was embedded in a polyethylene terephthalate film formed of a transparent conductive film made of indium tin oxide (ITO) on one side (OIKE & CO). .,LTD., ITO film, thickness: 125μm) Transparent conductive film, polycarbonate (PC) plate (manufactured by MITSUBISH GAS CHEMICAL COMPANY, INC., product name "IUPIRON‧ SHEET MR58", thickness: 1 mm), or acrylic made of polymethyl methacrylate (PMMA) A laminate (manufactured by MITSUBISH GAS CHEMICAL COMPANY, INC., product name "IUPIRON‧ SHEET MR200", thickness: 1 mm) was obtained.

The obtained laminate was placed under the conditions of 50 ° C and 0.5 Mpa, autoclaved for 30 minutes, and then placed under normal pressure, 23 ° C, 50% RH for 15 hours, followed by durability at 85 ° C and 85% RH. Store for 72 hours. After that, it is visually confirmed whether the adhesive layer has bubbles, floats, peeling, etc.

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

◎... There are no bubbles, floats and flaking at all.

○... Only bubbles having a diameter of 0.1 mm or less were produced.

×...The occurrence of bubbles, floating or peeling of a diameter exceeding 0.1 mm.

[Experimental Example 7] (Evaluation of film strength)

The adhesives of the adhesive sheets obtained in the examples and the comparative examples were laminated to have a total thickness of 1 mm, and then a cutting device (manufactured by OGINO SEISAKUSHO CO., LTD., product name "SUPER CUTTER PN1-600" ) cutting. After the 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.

○: There is no defect in the adhesive layer on the cut surface (high film strength)

×: There is a defect in the adhesive layer on the cut surface (low film strength)

[Experimental Example 8] (Evaluation of the step-tracking property)

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

The light release-type release sheet was unloaded from the adhesive sheets obtained in the examples and the comparative examples, and the exposed adhesive layer was attached to a polyester film containing an easy-adhesion layer (TOYOBO CO., LTD., product name) "PET A4300", thickness: 100 μm). The heavy peeling release sheet is then unloaded to allow the adhesive layer to be exposed. Then, a plastic sealing machine (product name "LPD3214" manufactured by FUJIPLA INC.) was used to completely cover the peripheral printing surface of the adhesive layer, and the glass plate between the layers of the laminated body was bonded to Evaluate the test sample.

The obtained sample for evaluation was placed under the conditions of 50 ° C and 0.5 MPa, autoclaved for 30 minutes, and then placed at normal pressure, 23 ° C, and 50% RH for 24 hours. Subsequently, the parallax traceability was evaluated after storage for 72 hours (durability test) under the endurance conditions of 85 ° C and 85% RH. The step tracking property is to judge whether or not the printing layer is completely filled with the printing step difference. If it is observed that there is a gap or a bubble between the printing step and the interface of the adhesive layer, it is judged that the printing step difference cannot be tracked. The step tracking property here is evaluated by the step tracking rate (%) presented in the following formula, and the results are shown in Table 2.

Step tracking rate (%) = {(the height of the step (μm) after maintaining the void-free or bubble-adhered state after the endurance test) / (thickness of the adhesive layer: 50 μm)} × 100

As shown in Table 2, the adhesive layer obtained in the examples had superior step tracking property and high film strength.

[Industrial Availability]

The adhesive sheet of the present invention is suitable for, for example, a joint use of a display body module and a stepped protective sheet.

Claims (11)

An adhesive agent, which is a type of display body member that has a step on which a surface on at least the bonding side is bonded, and a bonding agent that forms a member with another display body, wherein the adhesive agent is included as The unit of the polymer constituting monomer contains a (meth) acrylate polymer (A) having a reactive functional group monomer, an active energy ray-curable component (B) having two or more functional groups, and a bridging agent having a thermal bridging property ( The adhesive composition of 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 such that the adhesive is bridged Rate (G1) and the bridging ratio (G2) of the adhesive obtained by heat-bonding the adhesive composition other than the active energy ray-curable component (B) in the above-mentioned adhesive composition, substantially 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 measurement length is 20 mm, the extension speed is 200 mm/min, and the elongation is extended to the breaking elongation. The maximum stress can reach 2.8N or more. The adhesive agent according to claim 1, wherein the bridging ratio (G1) is 40 to 80%. The adhesive agent according to claim 1, wherein the adhesive layer has a thickness of 600 μm and a width of 10 mm, and the measurement length is 20 mm and the elongation speed is 200 mm in an environment of 23° C. and 50% RH. At the extension of /min, the breaking elongation is more than 1000%. The adhesive according to claim 1, wherein the (meth) acrylate polymer (A) has a weight average molecular weight of 200,000 to 1,000,000. The adhesive agent according to claim 1, wherein the above (meth) The acrylate polymer (A) contains 5 to 30% by mass of the reactive functional group-containing monomer as a monomer unit constituting the polymer. The adhesive according to claim 1, 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 Or epoxy bridging agent. An adhesive sheet having an adhesive layer made of an adhesive according to any one of claims 1 to 6. The adhesive sheet according to claim 7, wherein the thickness of the adhesive layer is 10 to 400 μm. The adhesive sheet according to claim 7, wherein the adhesive sheet has two release sheets, and the adhesive layer is sandwiched by the release sheet in contact with the release surface of the two release sheets. A display body, which is a display body having a display member forming member having at least a step on a bonding surface, another display member forming member, and an adhesive layer to which the display member constituent member and the other display member constituent member are attached. The adhesive layer is the adhesive layer of the adhesive sheet according to item 7. The display body according to claim 10, wherein the above-mentioned step is a frame pattern from a plane.