TW201723115A - Solventless adhesive composition, adhesive, adhesive sheet and display capable of exhibiting excellent blister resistance - Google Patents

Abstract

This invention provides a solventless adhesive composition capable of exhibiting excellent blister resistance, an adhesive, an adhesive sheet and a display. The solventless adhesive composition of this invention is characterized by comprising at least one polymerizable component selected from polymerizable vinyl monomer, polymerizable vinyl prepolymer, polyfunctional (meth)acrylate monomer and polyfunctional (meth)acrylate oligomer; and an organoalkoxysilane with a linear structure, and having an alkoxysilyl group at both terminals, wherein at least a part of the polymerizable component contains an active hydrogen group.

Description

Solvent-free adhesive composition, adhesive, adhesive sheet and display body

The present invention relates to a solventless adhesive composition, an adhesive, an adhesive sheet which can be used for a display body such as a touch panel, and a display body using the same.

In recent years, various mobile electronic devices such as a smart phone or a tablet computer include a display using a display body module, which is usually a touch panel, and the display body module has a liquid crystal element, a light emitting diode (LED element), and Electroluminescence (organic EL) elements and the like.

In the display as described above, a protective panel is usually provided on the surface side of the display body module. In the case of the protection panel, a gap is provided between the protection panel and the display body module to prevent the protection panel from being deformed when the protection panel is deformed by an external force to collide with the display body module.

However, if there is a void, that is, an air layer as described above, the difference in refractive index between the protective panel and the air layer and the reflection loss of light caused by the difference in refractive index between the air layer and the display module increase, and there is a display. The problem of degraded picture quality. Therefore, it has been proposed to improve the image quality of the display by filling the gap between the protective panel and the display body module with the adhesive layer.

On the other hand, with the reduction in thickness and weight of electronic devices, it has been studied to change the above-mentioned protective panel from a conventional glass plate to an acrylic plate or a polycarbon. Acid plate and other plastic plates. Here, in the aspect in which the gap between the protective panel and the display body module is filled with the adhesive layer, when the protective panel is changed to the plastic plate, air leakage occurs from the plastic plate under high temperature and high humidity conditions, and bubbles are generated. New problems such as bubbling, peeling, and peeling. Therefore, foaming resistance is often required to fill the adhesive between the display body module and the protective panel.

As an example of the adhesive composition for forming the above-mentioned adhesive layer, Patent Document 1 discloses an adhesive composition for a touch panel containing an epoxy-based decane coupling agent. Further, in Patent Document 2, as a flat panel display panel mainly used for a plasma display panel or a liquid crystal display, an adhesive composition containing a (meth)acryloxy group-containing decane coupling agent is disclosed.

[Previous Technical Literature] [Patent Literature]

Patent Document 1: Japanese Laid-Open Patent Publication No. 2013-544931

Patent Document 2: Japanese Laid-Open Patent Publication No. 2014-133812

Here, in the adhesive composition containing the epoxy decane coupling agent disclosed in Patent Document 1, in order to effectively exhibit the coupling action, it is very important to carry out the ring opening reaction of the epoxy group efficiently. Therefore, in general, the adhesive composition contains a monomer or a polymer having an acidic group. However, the adhesive for a touch panel is required to be free from acid in order not to deteriorate the transparent conductive film to be adherend. Therefore, the adhesive composition disclosed in Patent Document 1 cannot satisfy the effect of sufficiently obtaining an epoxy-based coupling agent without containing an acid. As a result, the effect of improving the adhesion of the obtained adhesive to the adherend becomes insufficient. Therefore, it is difficult to The adhesive composition disclosed in Patent Document 1 is obtained as an adhesive which does not contain an acid and exhibits sufficient foaming resistance.

Further, in Patent Document 2, specific examples of the (meth)acryloxy group-containing decane coupling agent include a (meth) acryloxy group at one terminal and an alkoxy fluorenyl group at the other terminal. Compound (paragraph 0038 of Patent Document 2). The adhesive composition disclosed in Patent Document 2 contains a (meth) acrylate polymer and a (meth) acrylate monomer in addition to the coupling agent. When the adhesive composition is hardened, it is presumed that the (meth)acryloxy group of the coupling agent is also involved in the radical polymerization reaction between the polymers and the monomers, and as a result, the coupling agent is uniformly dispersed. It is incorporated in the state of the adhesive. Therefore, in the adhesive composition disclosed in Patent Document 2, the decane coupling agent is present in the vicinity of the surface of the adhesive layer, and the effect of improving the adhesion is not obtained. As a result, the adhesive obtained from the adhesive composition disclosed in Patent Document 2 cannot exhibit sufficient foaming resistance.

The present invention has been made in view of such actual circumstances, and an object thereof is to provide a solventless adhesive composition, an adhesive, an adhesive sheet, and a display body which can exhibit excellent foaming resistance.

In order to achieve the above object, first, the present invention provides a solventless adhesive composition characterized by comprising: a polymerizable vinyl monomer, a polymerizable vinyl prepolymer, and a polyfunctional (meth) acrylate. At least one of a monomeric component and a polyfunctional (meth)acrylate oligomer; and an organoalkoxydecane having a linear structure and having an alkoxyfluorenyl group at both ends thereof, the above-mentioned polymerization component At least a portion of it contains an active hydrogen group (Invention 1).

It is presumed that the solventless adhesive composition of the above invention (Invention 1), in addition to the radical polymerization reaction of the polymerization components, also undergoes a hydrolysis condensation reaction between the polymerization component and the organoalkoxydecane at the time of curing. Further, it is presumed that the hydrolysis condensation reaction mainly occurs in the vicinity of the surface of the adhesive layer, so that the proportion of the organoalkoxydecane present in the vicinity of the surface of the adhesive layer is increased. By these, the adhesive layer obtained from the adhesive composition is excellent in cohesive force and excellent in adhesion to an adherend. As a result, the adhesive can exhibit excellent foaming resistance.

In the above invention (Invention 1), it is preferred that the active hydrogen group is a hydroxyl group (Invention 2).

In the above-mentioned invention (Inventions 1 and 2), it is preferred that the solvent-free adhesive composition contains at least the polymerizable vinyl monomer and the polyfunctional (meth)acrylate oligomer as the polymerization component (Invention 3) ).

In the above invention (Inventions 1 to 3), it is preferred that the solvent-free adhesive composition further contains a photopolymerization initiator (Invention 4).

In the above invention (Inventions 1 to 4), the content of the organoalkoxydecane in the solvent-free adhesive composition is preferably 0.01 parts by mass or more and 20 parts by mass or less based on 100 parts by mass of the polymerization component. Invention 5).

Secondly, the present invention provides an adhesive which is obtained by hardening the solvent-free adhesive composition (Inventions 1 to 5) (Invention 6).

In the above invention (Invention 6), the gel fraction of the adhesive is preferably 50% or more and 100% or less (Invention 7).

Third, the present invention provides an adhesive sheet having an adhesive layer formed of the aforementioned adhesive (Inventions 6, 7) (Invention 8).

In the above invention (Invention 8), the pressure-sensitive adhesive sheet includes two release sheets, and the pressure-sensitive adhesive layer is preferably sandwiched by the release sheet so as to be in contact with the release surface of the two release sheets (Invention 9).

Thirdly, the present invention provides a display body comprising: a display body constituting member having a step at least on a surface to be attached; another display body constituting member; an adhesive layer affixing to each other to form a display body constituting member And the other display member constituting member, wherein the adhesive layer is an adhesive layer of the adhesive sheet (Inventions 8, 9).

The solventless adhesive composition, the adhesive, the adhesive sheet, and the display of the present invention can exhibit excellent foaming resistance.

1‧‧‧Adhesive film

11‧‧‧Adhesive layer

12a, 12b‧‧‧ peeling film

2‧‧‧Display

21‧‧‧1st display body constituent member

22‧‧‧2nd display body constituent member

3‧‧‧Printing layer

Fig. 1 is a cross-sectional view showing an adhesive sheet according to an embodiment of the present invention.

Fig. 2 is a cross-sectional view showing a laminated body according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described.

[Solvent-free adhesive composition]

The solventless adhesive composition of the present embodiment (hereinafter sometimes referred to as "solvent-free adhesive composition P") contains: a polymerizable vinyl monomer, a polymerizable vinyl prepolymer, and a plurality of At least one of a functional (meth) acrylate monomer and a polyfunctional (meth) acrylate oligomer; and an organoalkoxy decane having a linear structure and having an alkoxy group at both ends thereof Base base. Here, at least a part of the above polymerization component contains an active hydrogen group. In addition, this manual In the above, (meth) acrylate means both acrylate and methacrylate. Other similar terms are also the same.

In the solventless adhesive composition P of the present embodiment, the radical polymerization reaction of the polymerization components is carried out at the time of curing, and the active hydrogen group of the polymerization component and the alkoxy group of the organic alkoxy decane are contained. A hydrolysis condensation reaction is carried out between the groups. Since the hydrolysis condensation reaction proceeds more slowly than the radical polymerization reaction, it is estimated that the hydrolysis condensation reaction occurs after the radical polymerization reaction is mainly performed to some extent. Therefore, it is estimated that the proportion of the organoalkoxydecane present in the vicinity of the surface of the adhesive layer is increased. Further, this hydrolysis condensation reaction occurs in the alkoxyfluorenyl group present at both terminals of the organoalkoxydecane, and thus a structure in which the organoalkoxydecane is crosslinked between the polymerization components is formed. It is presumed that the structure reinforces the adhesive in a manner different from the structure formed by radical polymerization of the polymerization components, and the cohesive force is effectively enhanced, so that the obtained adhesive has a very high cohesive force. As a result, the adhesive layer obtained from the solventless adhesive composition P of the present embodiment is excellent in cohesive force and excellent in adhesion to an adherend.

According to the above, the adhesive obtained by using the solventless adhesive composition P of the present embodiment can exhibit excellent foaming resistance. For example, the display obtained by using the solventless adhesive composition P of the present embodiment is exposed to high temperature and high humidity (for example, 85 ° C, 85% RH) to cause leakage from a display member including a plastic plate or the like. In the case of gas, it is also possible to suppress generation of bubbles such as bubbles, floatation, and peeling at the interface between the adhesive layer and the display constituent member.

Further, the above-described reaction or the structure of the formed system in which the solventless adhesive composition P of the present embodiment is cured may be inferred. React or form other structures. For example, the alkoxythiol group at both ends of the organoalkoxydecane need not necessarily be bonded to an active hydrogen group, and the alkoxythio group at the terminal may remain unreacted. Further, the organoalkoxydecane may be hydrolyzed and condensed to each other to form an organoalkoxydecane repeating structure, and the alkoxyfluorenyl groups at both terminals or one terminal may be bonded to the active hydrogen group of the polymerization component. Further, the organoalkoxydecane may be present not only in the vicinity of the surface of the adhesive layer but also in the interior.

(1) Polymeric components

The solventless adhesive composition P of the present embodiment contains a polymerizable vinyl monomer, a polymerizable vinyl prepolymer, a polyfunctional (meth) acrylate monomer, and a polyfunctional (meth) acrylate oligo. At least one polymeric component of the polymer.

In the solventless adhesive composition P of the present embodiment, at least a part of the polymerization component has an active hydrogen group. At least one of the active hydrogen group-based hydroxyl group and the carboxyl group is preferred, and the difference in the rate of the radical polymerization reaction and the hydrolysis condensation reaction as described above becomes clear and the organoalkoxydecane is easily present in the adhesive layer. From the viewpoint of the vicinity of the surface, the hydroxyl group is particularly preferable. In general, when a touch panel or the like is placed in a high-temperature and high-humidity environment, moisture is immersed in the adhesive layer, and when the touch panel or the like is returned to normal temperature, the adhesive layer may be whitened to cause "wet heat whitening" in which the transparency is lowered. The problem. Here, the radical contains the active hydrogen group, and the group is present in the obtained adhesive. Since the compatibility of the group with the water to be immersed is good, as a result, whitening of the pressure-sensitive adhesive layer can be suppressed, and the pressure-sensitive adhesive is excellent in resistance to moist heat whitening.

Among the above four types, it is preferred that the polymerization component contains at least a polymerizable vinyl monomer and a polyfunctional (meth) acrylate oligomer. By polymerization By including these compounds, the cohesive force of the obtained adhesive is improved, and an adhesive excellent in foaming resistance can be obtained.

(1-1) Polymerizable vinyl monomer

The polymerizable vinyl monomer is not particularly limited as long as it has a group containing a vinyl group, and a conventionally known one can be suitably used. In addition, the polymerizable vinyl single system in the present embodiment means a polymerizable vinyl monomer having one vinyl group-containing group, and does not overlap with a polyfunctional (meth)acrylate monomer to be described later.

Specific examples of the polymerizable vinyl monomer include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, and (methyl). Amyl acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethyl (meth) acrylate, isooctyl (meth) acrylate, decyl (meth) acrylate, (A) Base) lauryl acrylate, tetradecyl (meth) acrylate, cetyl (meth) acrylate, octadecyl (meth) acrylate, lauryl (meth) acrylate, Isobornyl (meth)acrylate, phenoxyethyl (meth)acrylate, benzyl (meth)acrylate, polyoxyalkylene modified (meth)acrylate, etc. do not have a vinyl group in the molecule. A (meth) acrylate of a functional group other than the group. Among these, 2-ethylhexyl acrylate or isobornyl acrylate is preferred.

Further, the polymerizable vinyl monomer may be a functional group other than a group having a vinyl group in the molecule. Examples of the functional group include the above-mentioned active hydrogen group, that is, a hydroxyl group, a carboxyl group, a thiol group, and a primary or secondary amine group. Specific examples of the polymerizable vinyl monomer having such a functional group include 2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate. (meth)acrylic acid hydroxy group (3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate Alkyl ester; hydroxyl group-containing acrylamide such as N-methylol acrylamide or N-methylol methacrylamide; acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, and lemon An ethylenically unsaturated carboxylic acid such as a benechoic acid. Among these, 2-hydroxyethyl acrylate is preferred.

Further, examples of the other polymerizable vinyl monomer include vinyl esters such as vinyl acetate and vinyl propionate; olefins such as ethylene, propylene, and isobutylene; halogenated olefins such as vinyl chloride and vinylidene chloride; and styrene; a styrene monomer such as α-methylstyrene; a diene monomer such as butadiene, isoprene or chloroprene; a nitrile monomer such as acrylonitrile or methacrylonitrile; and acrylamide , methacrylamide, N-methyl acrylamide, N-methyl methacrylamide, N,N-dimethyl(meth) acrylamide, N,N-diethyl (methyl a guanamine monomer such as acrylamide or N-vinylpyrrolidone; a tertiary amino group such as N,N-diethylaminoethyl (meth)acrylate or N-(methyl)propene morpholine Monomers, etc.

(1-2) Polymerizable vinyl prepolymer

The polymerizable vinyl prepolymer is not particularly limited, and a conventionally known polymer prepolymer obtained by polymerizing the above-mentioned polymerizable vinyl monomer is preferably used. In the present specification, the prepolymer refers to a compound obtained by polymerizing a monomer, and can be a compound of a polymer by performing further polymerization.

In addition, when the polymerizable vinyl monomer is polymerized to obtain a polymerizable vinyl prepolymer, the monomer may be polymerized alone or in combination of plural kinds.

Further, the polymerizable vinyl prepolymer may be obtained by radical polymerization, or may be obtained by living polymerization, and in particular, may be a polymer remaining at the end of RAFT (Reversible Addition-Fragmentation Chain Transfer Polymerization).

The weight average molecular weight of the polymerizable vinyl prepolymer is preferably 6,000 or more, more preferably 7,500 or more, and still more preferably 10,000 or more. Further, the weight average molecular weight is preferably 1,500,000 or less, more preferably 1,000,000 or less, and still more preferably 100,000 or less. When the weight average molecular weight is within the above range, the viscosity of the solventless adhesive composition P is easily set to a desired range. Further, the weight average molecular weight in the present specification is a value in terms of standard polystyrene measured by a gel permeation chromatography (GPC) method.

(1-3) Polyfunctional (meth) acrylate monomer

The polyfunctional (meth) acrylate monomer is not particularly limited, and those conventionally known can be suitably used.

In particular, as the polyfunctional (meth) acrylate monomer, a monomer having two or more (meth) acrylonitrile groups in one molecule can be preferably mentioned. Examples of such a monomer include 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and neopentyl glycol di(methyl). Acrylate, polyethylene glycol di(meth)acrylate, neopentyl glycol adipate di(meth)acrylate, hydroxypivalic acid neopentyl glycol di(meth)acrylate, dicyclopentyl Di(meth) acrylate, caprolactone modified dicyclopentenyl di(meth) acrylate, ethylene oxide modified di(meth) acrylate, bis(propylene oxiranyl) Cyanurate, allylated cyclohexyl di(meth) acrylate, trimethylolpropane tri(meth) acrylate, dipentaerythritol tri(methyl) Acrylate, propionic acid modified dipentaerythritol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, propylene oxide modified trimethylolpropane tri(meth)acrylate, tris(propylene oxide B Iso-isocyanurate, bis(acryloyloxyethyl)hydroxyethyl isocyanurate, isocyanuric acid ethylene oxide modified diacrylate, isocyanuric acid ethylene oxide modified three Acrylate, ε-caprolactone modified tris(propylene oxyethyl) isocyanurate, diglycerin tetra (meth) acrylate, pentaerythritol tetra (meth) acrylate, propionic acid modified dipentaerythritol (Meth) acrylate, dipentaerythritol hexa (meth) acrylate, caprolactone modified dipentaerythritol hexa (meth) acrylate, and the like.

(1-4) Polyfunctional (meth) acrylate oligomers

The polyfunctional (meth) acrylate oligomer is not particularly limited, and a conventionally known one can be suitably used, but a polyfunctional (meth)acrylic acid having two or more (meth) acrylonitrile groups in one molecule is used. Ester oligomers are preferred. Examples of such oligomers include urethane acrylate type, polyester acrylate type, epoxy acrylate type, polyether acrylate type, polybutadiene acrylate type, and fluorenone acrylate. An oligomer such as an ester.

The urethane acrylate oligomer can be, for example, a polyalkylene polyol, a polyether polyol, a polyester polyol, a hydrogenated isoprene having a hydroxyl group terminal, and a hydrogenated butyl group having a hydroxyl group terminal. A polyurethane oligomer obtained by reacting a compound such as an ene with a polyisocyanate is obtained by esterification using a (meth)acrylic acid or a (meth)acrylic acid derivative.

Here, examples of the polyalkylene polyol used in the production of the urethane acrylate oligomer include polypropylene glycol, polyethylene glycol, polytetramethylene glycol, and polyhexanediol. Etc., the use of polypropylene glycol is particularly good. In addition, when When the number of functional groups of the obtained urethane acrylate-based oligomer is three or more, glycerin, trimethylolpropane, triethanolamine, pentaerythritol, ethylenediamine, diethylenetriamine, and the like are appropriately combined. Sorbitol, sucrose, etc. can be used.

Further, examples of the polyisocyanate include aliphatic diisocyanates such as hexamethylene diisocyanate and trimethylene diisocyanate; and aromatic diisocyanates such as toluene diisocyanate, xylene diisocyanate, and diphenyl diisocyanate; Among them, an aliphatic diisocyanate such as cyclohexylmethane diisocyanate or isophorone diisocyanate is preferably used, and an aliphatic diisocyanate is preferably used, and hexamethylene diisocyanate is particularly preferred. Further, the polyisocyanate is not limited to a bifunctional one, and a trifunctional or higher functional group may also be used.

Further, examples of the (meth)acrylic acid derivative include a hydroxyalkyl (meth)acrylate such as 2-hydroxyethyl acrylate or 4-hydroxybutyl acrylate, 2-isocyanate ethyl acrylate, and 2-isocyanate B. The base methacrylate, 1,1-bis(acryloxymethyl)ethyl isocyanate or the like is particularly preferably 2-isocyanate ethyl acrylate.

Another method for producing a urethane acrylate oligomer can also be obtained by polyalkylene polyol, polyether polyol, polyester polyol, hydrogenated isoprene having a hydroxyl group, A reaction between a hydroxyl group of a compound such as a hydrogenated butadiene having a hydroxyl group and a -N=C=O portion of an alkyl isocyanate (meth)acrylate to obtain a urethane acrylate oligomer . In this case, as the isocyanate (meth) acrylate, the above 2-isocyanate ethyl acrylate, 2-isocyanate ethyl methacrylate, 1,1-bis(propylene methoxymethyl group) can be used. Ethyl isocyanate and the like.

The polyester acrylate oligomer can be obtained, for example, by: The hydroxyl group of the polyester oligomer having a hydroxyl group at both terminals obtained by condensation of a polyvalent carboxylic acid and a polyhydric alcohol is esterified with (meth)acrylic acid, or an alkylene oxide is added to the polyvalent carboxylic acid. The hydroxyl group at the terminal of the obtained oligomer was esterified with (meth)acrylic acid.

The epoxy acrylate oligomer can be obtained, for example, by reacting (meth)acrylic acid with an oxirane ring of a relatively low molecular weight bisphenol epoxy resin or a novolac epoxy resin. Further, a carboxyl-modified epoxy acrylate-based oligomer obtained by partially modifying an epoxy acrylate oligomer with a dicarboxylic acid anhydride can also be used.

The polyether acrylate oligomer can be obtained, for example, by esterifying a hydroxyl group of a polyether polyol with (meth)acrylic acid.

The weight average molecular weight of the polyfunctional (meth) acrylate oligomer is preferably 10,000 or more, and particularly preferably 20,000 or more. Further, the weight average molecular weight is preferably 350,000 or less, and more preferably 200,000 or less.

(1-5) Proportion

When a polymerizable vinyl monomer and a polyfunctional (meth) acrylate oligomer are used as a polymerization component, the mass of the polymerizable vinyl monomer is divided by the polyfunctional (meth) acrylate oligomer The ratio of the mass obtained is preferably 0.18 or more, more preferably 1 or more, and further preferably 1.5 or more. Further, the ratio is preferably 999 or less, particularly preferably 19 or less, and further preferably 9 or less.

(2) organoalkoxydecane

The solventless adhesive composition P of the present embodiment contains an organoalkoxydecane having a linear structure and having an alkoxyfluorenyl group at both ends thereof. Here, "straight chain" of "linear structure" substantially means "straight chain". In other words, the linear structure may have a branched structure or may have a cyclic structure as long as the effect of crosslinking the polymerization components between the alkoxysilanes is well exhibited. Further, having an alkoxyfluorenyl group at both ends means having an alkoxyfluorenyl group at both end portions of the linear structure.

The above organoalkoxydecane preferably has a plurality of alkoxyfluorenyl groups at at least one terminal. That is, the organoalkoxydecane preferably has two alkoxyfluorenyl groups or three alkoxyfluorenyl groups at at least one terminal, and particularly preferably contains three alkoxyfluorenyl groups. When the organoalkoxydecane contains a plurality of alkoxyfluorenyl groups at at least one terminal, the bonding with the active hydrogen group of the polymerization component is facilitated, and as a result, the cohesive force of the obtained adhesive is higher. .

Examples of the alkoxyfluorenyl group include a methoxy fluorenyl group, an ethoxylated fluorenyl group, a n-propoxy fluorenyl group, an isopropoxy fluorenyl group, a n-butoxy fluorenyl group, and a sec-butoxy fluorene group. A group, an isobutoxycarbonyl group, a tert-butoxycarbonyl group, and the like. Among these, a methoxy fluorenyl group is preferable from the viewpoint of obtaining excellent blister resistance.

The above organoalkoxydecane does not have a group capable of reacting with a polymerization component other than the alkoxyfluorenyl group. Examples of the reactive group other than the alkoxyfluorenyl group include a (meth)acryloxy group, a vinyloxy group, and an allyloxy group. Since the above organoalkoxydecane does not have such a group, the organoalkoxydecane can be suppressed from being uniformly absorbed into the polymerization component. Thereby, the ratio of the organoalkoxydecane present in the vicinity of the surface of the obtained adhesive layer is increased, and the adhesion of the adhesive layer to the adherend is further improved. Further, the reaction of the alkoxyfluorenyl group with the active hydrogen group in the polymerization component is carried out without hindrance by the absence of a group other than the alkoxyfluorenyl group. Thereby, an organic alkoxysilane is favorably formed in the obtained adhesive layer to crosslink the polymerization components. The structure, the cohesion of the surface of the adhesive layer is further improved. As a result of the above, the obtained adhesive layer was excellent in foaming resistance.

Examples of the organoalkoxydecane contained in the solventless adhesive composition P of the present embodiment include bis(alkoxyindenyl)alkane and 1,4-bis(alkoxyfluorenyl). An aromatic compound such as benzene or 1,4-bis(alkoxydecylalkyl)benzene; 1,2-bis(alkoxyfluorenyl)oxirane, 1,3-bis(alkoxycarbonyl) An alkylene oxide compound such as propylene oxide; 1,3-bis(alkoxymethyl)cyclobutane, 1,3-bis(alkoxydecylalkyl)cyclobutane, 1,4-double ( An alicyclic compound such as alkoxyfluorenyl)cyclohexane or 1,4-bis(alkoxydecylalkyl)cyclohexane. Among these, bis(alkoxydecyl)alkane is particularly preferable from the viewpoint that the molecular volume is small and it is easy to form a bond with the active hydrogen group of the adhesive.

The alkane-based carbon number of the bis(alkoxyalkyl)alkane is preferably 1 or more, particularly preferably 3 or more, and more preferably 5 or more. Further, the alkane-based carbon number is preferably 20 or less, particularly preferably 10 or less, and more preferably 7 or less.

Preferable examples of the bis(alkoxyalkyl)alkane include 1,6-bis(trimethoxyindenyl)hexane and 1,7-bis(trimethoxyindenyl)heptane, 1. 8-bis(trimethoxyindenyl)octane and the like. Among these, from the viewpoint of obtaining excellent blister resistance, 1,6-bis(trimethoxyindenyl)hexane or 1,8-bis(trimethoxyindenyl)octane is used. good.

The content of the above-mentioned organoalkoxydecane in the solvent-free adhesive composition P is preferably 0.01 parts by mass or more, more preferably 0.05 parts by mass or more, and 0.1 parts by mass or more, more preferably 100 parts by mass of the polymerization component. Preferably. Further, the content is 20 parts by mass based on 100 parts by mass of the polymerization component. The following is preferable, and 10 parts by mass or less is particularly preferable, and 3 parts by mass or less is further more preferable. When the content is within the above range, the above effects based on the above organoalkoxydecane can be sufficiently obtained.

(3) polymerization initiator

The solventless adhesive composition P of the present embodiment further preferably contains a polymerization initiator. The solvent-free adhesive composition P can be effectively cured by containing a polymerization initiator.

The polymerization initiator is not particularly limited, and may be a conventionally known one. However, it is preferably selected according to the curing state of the solvent-free adhesive composition P. In other words, when the solvent-free adhesive composition P is cured by irradiation with ultraviolet rays as an active energy ray, a photopolymerization initiator is preferably used as the polymerization initiator. Further, when the solventless adhesive composition P is cured by heating, a thermal polymerization initiator is preferably used. A photopolymerization initiator and a thermal polymerization initiator may also be used in combination.

Examples of the photopolymerization initiator include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1 -ketone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propan-1-one, 4-(2-hydroxyethyl) Oxy)phenyl-2-(hydroxy-2-propyl)one, benzophenone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichlorodiphenyl Methyl ketone, 2-methyl hydrazine, 2-ethyl hydrazine, 2-tert-butyl fluorene, 2-amino hydrazine, 2-methyl thioxanthone, 2-ethyl thioxanthone, 2- Chlorothenoxone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyldimethylketal, acetophenone Dimethyl ketal, p-dimethylamino benzoate, oligo[2-hydroxy-2-methyl-1[4-(1-methylvinyl)phenyl]propanone], 2,4 , 6-trimethylbenzimidyl-diphenyl-phosphine oxide, and the like. These may be used alone or in combination of two or more.

Examples of the thermal polymerization initiator include persulfate such as potassium persulfate or ammonium persulfate, benzammonium peroxide, peroxide such as lauric acid peroxide, azo compound such as azobisisobutyronitrile, and the like. . These may be used singly or in combination of two or more.

The content of the polymerization initiator in the solvent-free adhesive composition P is preferably 0.1 parts by mass or more, more preferably 0.3 parts by mass or more, and even more preferably 0.5 parts by mass or more, based on 100 parts by mass of the polymerization component. In addition, the content is preferably 10 parts by mass or less based on 100 parts by mass of the polymerization component, more preferably 5 parts by mass or less, and still more preferably 3 parts by mass or less. By the content of 0.1 part by mass or more, the curing of the solvent-free adhesive composition P can be effectively performed. On the other hand, when the content is 10 parts by mass or less, the polymerization initiator remaining unreacted at the time of curing can be eliminated or reduced, and the obtained adhesive can be easily set to desired physical properties.

(4) Various additives

In the solventless adhesive composition P, various additives such as a decane coupling agent, an ultraviolet absorber, an antistatic agent, an adhesion promoter, an antioxidant, a light stabilizer, a softener, a filler, and a refractive index adjustment may be added as needed. Agents, etc. In addition, the polymerization solvent to be described later is not included in the additive constituting the solventless adhesive composition P.

Here, if the solventless adhesive composition P contains a decane coupling agent, the adhesion between the obtained adhesive and the glass member or the plastic plate is improved. high. Thereby, the obtained adhesive becomes more excellent in foaming resistance.

The decane coupling agent is an organic ruthenium compound having at least one alkoxyfluorenyl group in the molecule other than the above-described organoalkoxy decane, and has good compatibility with the above-mentioned polymerization component and organoalkoxy decane. Light transmissive is preferred.

Examples of the decane coupling agent include a fluorene compound containing a polymerizable unsaturated group such as vinyl trimethoxy decane, vinyl triethoxy decane or methacryloxypropyl trimethoxy decane. a fluorene compound having an epoxy group structure such as 3-glycidoxypropyltrimethoxydecane or 2-(3,4-epoxycyclohexyl)ethyltrimethoxydecane, 3-mercaptopropyltrimethoxy An anthracenyl-containing fluorene compound such as decane, 3-mercaptopropyltriethoxydecane or 3-mercaptopropyldimethoxymethylnonane, 3-aminopropyltrimethoxydecane, N-(2-amino group An amine group-containing oxime compound such as ethyl)-3-aminopropyltrimethoxydecane or N-(2-aminoethyl)-3-aminopropylmethyldimethoxydecane, 3-chloro Propyltrimethoxydecane, 3-isocyanatepropyltriethoxydecane, or at least one of these with methyltriethoxydecane, ethyltriethoxydecane, methyltrimethoxydecane, ethyl A condensate of an alkyl group-containing quinone compound such as trimethoxy decane or the like. These may be used alone or in combination of two or more.

When the solvent-free adhesive composition P contains a decane coupling agent, the content thereof is preferably 0.01 parts by mass or more, more preferably 0.05 parts by mass or more, and further preferably 0.1 parts by mass or more, based on 100 parts by mass of the polymerization component. . In addition, the content is preferably 1 part by mass or less based on 100 parts by mass of the polymerization component, more preferably 0.5 part by mass or less, and further preferably 0.3 part by mass or less.

(5) Manufacture of solvent-free adhesive composition

The solventless adhesive composition P can be produced by mixing a polymerization component and an organoalkoxysilane and adding an additive as needed.

Further, since the solventless adhesive composition P of the present embodiment is a solventless type, it has a moderate viscosity mainly by a polymerization component. Therefore, the solventless adhesive composition P of the present embodiment can be directly used as a coating solution without adding a diluent or the like.

[adhesive]

The adhesive of the present embodiment is obtained by curing the solvent-free adhesive composition P. The hardening of the solvent-free adhesive composition P can be carried out by irradiation of active energy rays or by heat treatment depending on the material contained in the composition P. Thus, "hardening" in the present specification includes both hardening by irradiation of active energy ray and hardening by heat treatment unless otherwise specified.

The hardening of the solvent-free adhesive composition P is preferably carried out by irradiation with active energy rays. By this, it is possible to prevent thermal deterioration, heat shrinkage, and the like of the resin film or the like to be applied as the solvent-free adhesive composition P without applying heat during curing. Further, since the heating is not performed, it is possible to suppress the volatile component in the solventless adhesive composition P from disappearing due to heating.

The active energy ray refers to an energy source having an electromagnetic wave or a charged particle beam, and specifically, an ultraviolet ray, an electron beam, or the like. Among the active energy rays, ultraviolet rays which are easy to handle are particularly preferable.

The irradiation of the ultraviolet ray can be carried out by a high pressure mercury lamp, a fused H lamp, a xenon lamp or the like, and the illuminance is preferably 50 mW/cm ² or more and 1000 mW/cm ² or less. Light amount is more preferably ^2-based, 80mJ / cm ² or more is more preferably 50mJ / cm, ² is particularly preferably more than 200mJ / cm. Further, the light amount is preferably 10000 mJ/cm ² or less, more preferably 5,000 mJ/cm ² or less, and particularly preferably 2,000 mJ/cm ² or less. On the other hand, the irradiation of the electron beam can be performed by an electron beam accelerator or the like, and the irradiation amount of the electron beam is preferably 10 krad or more and 1000 krad or less.

The heating temperature of the heat treatment is preferably 50 ° C or more, and particularly preferably 70 ° C or more. Further, the heating temperature is preferably 150 ° C or lower, and particularly preferably 120 ° C or lower. The heating time of the heat treatment is preferably 10 seconds or more, and more preferably 50 seconds or more. Further, the heating time is preferably 10 minutes or less, and particularly preferably 90 seconds or less. It is also possible to use the drying treatment after applying the solventless adhesive composition P as the heat treatment.

Further, when the adhesive of the present embodiment is produced, the active energy ray may be irradiated after the heat treatment, or both treatments may be simultaneously performed. Further, after the heat treatment or after the active energy ray irradiation, it is also preferable to provide a aging period of about 1 to 2 weeks at normal temperature (for example, 23 ° C, 50% RH).

The gel fraction of the adhesive of the present embodiment is preferably 50% or more, more preferably 55% or more, and still more preferably 60% or more. Further, the gel fraction is preferably 100% or less, more preferably 80% or less, and still more preferably 70% or less. When the gel fraction of the adhesive is within the above range, the cohesive force of the adhesive is increased, and the foaming resistance is further improved. Here, the method of measuring the gel fraction of the adhesive is as shown in the test examples described later.

The adhesive of the present embodiment is obtained by curing the above-described solvent-free adhesive composition P. Therefore, at the time of hardening, polymerization of the polymerization components and polymerization reaction of the organoalkoxysilane with the active hydrogen group are carried out. The centering is performed near the surface, so that a strong crosslinked structure is formed in the adhesive. As a result, the adhesive of the present embodiment has a very high cohesive force. In other words, the adhesive of the present embodiment partially increases the cohesive force of the surface in contact with the adherend, and becomes flexible as a whole. Thereby, the adhesive of the present embodiment has sufficient step followability and can exhibit excellent foaming resistance.

[adhesive sheet]

The adhesive sheet of the present embodiment has an adhesive layer for bonding one display body constituent member and another display body constituent member, and the adhesive layer includes the above-mentioned adhesive.

A specific configuration of an example of the adhesive sheet of the present embodiment is shown in Fig. 1.

As shown in Fig. 1, the adhesive sheet 1 of one embodiment is composed of two release sheets 12a and 12b and two release sheets which are in contact with the peeling faces of the two release sheets 12a and 12b. Adhesive layer 11 held by 12a, 12b. In addition, the peeling surface of the peeling sheet in this specification is the surface which has the peeling property in the peeling sheet, and is the surface which carried out the peeling process, and the surface which shows the peeling-

(1) Adhesive layer

The adhesive layer 11 is composed of the above-mentioned adhesive, that is, an adhesive obtained by hardening the solvent-free adhesive composition P.

The thickness of the adhesive layer 11 in the adhesive sheet 1 of the present embodiment (value measured in accordance with JIS K7130:1999) is preferably 10 μm or more, more preferably 25 μm or more, particularly preferably 50 μm or more, and further preferably 75 μm or more. . Further, the thickness is preferably 1000 μm or less, more preferably 400 μm or less, and 300 μm. The following is especially good. Further, the adhesive layer 11 may be formed of a single layer or may be formed by laminating a plurality of layers.

When the thickness of the adhesive layer 11 is 10 μm or more, it is easy to exhibit a desired adhesive force. In addition, when the thickness of the adhesive layer 11 is 1000 μm or less, the workability is good.

(2) peeling sheet

The release sheets 12a and 12b are used to protect the adhesive layer 11 before the adhesive sheet 1 is used, and are peeled off when the adhesive sheet 1 (adhesive layer 11) is used. In the adhesive sheet 1 of the present embodiment, one or both of the release sheets 12a and 12b are not necessarily required.

As the release sheets 12a and 12b, for example, a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a polymethylpentene film, a polyvinyl chloride film, a vinyl chloride copolymer film, or a polyparaphenylene is used. Ethylene formate film, polyethylene naphthalate film, polybutylene terephthalate film, urethane film, ethylene ethyl acetate film, ionomer resin film, ethylene ‧ (methyl) An acrylic copolymer film, a vinyl ‧ (meth) acrylate copolymer film, a polystyrene film, a polycarbonate film, a polyimide film, a fluororesin film, or the like. Further, these crosslinked films can also be used. Alternatively, these laminated films may be used.

It is preferable that the release surface of the release sheets 12a and 12b (especially the surface in contact with the adhesive layer 11) is subjected to a release treatment. Examples of the release agent used in the release treatment include an alkyd type, an anthrone type, a fluorine type, an unsaturated polyester type, a polyolefin type, and a wax type release agent. Further, in the release sheets 12a and 12b, one release sheet is a heavy release type release sheet having a large peeling force, and the other release sheet is preferably a light release type release sheet having a small peeling force.

The thickness of the release sheets 12a and 12b is not particularly limited, but is usually 20 μm or more and 150 μm or less.

(3) Physical properties

(3-1) Adhesion

The adhesive sheet 1 of the present embodiment preferably has an adhesion to soda-lime glass of 5 N/25 mm or more, more preferably 10 N/25 mm or more, and further preferably 15 N/25 mm or more. Further, the adhesive force is preferably 50 N/25 mm or less, particularly preferably 40 N/25 mm or less, and further preferably 35 N/25 mm or less. When the adhesive force of the adhesive sheet 1 is 5 N/25 mm or more, the foaming resistance is further improved. Further, when the adhesive force of the adhesive sheet 1 is 50 N/25 mm or less, good reworkability can be obtained, and when erroneous bonding occurs, an expensive display member can be reused. Here, the adhesive force in the present specification basically means an adhesive force measured by a 180-degree peeling method in accordance with JIS Z0237:2009, and the specific measurement method is as shown in a test example described later.

(3-2) haze value

The adhesive layer 11 of the adhesive sheet 1 of the present embodiment preferably has a haze value of 5% or less, more preferably 1% or less, and even more preferably 0.5% or less. When the haze value of the adhesive layer 11 is 5% or less, transparency is high, and it is suitable for optical use (for display bodies). In addition, the haze value in this specification is set to the value measured by JIS K7136:2000.

(3-3) Total light transmittance

The total light transmittance of the adhesive layer 11 of the adhesive sheet 1 of the present embodiment is preferably 90% or more, more preferably 95% or more, and still more preferably 98% or more. If the total light transmittance is 98% or more, the transparency is very high, and it is suitable for use. Optical use. Further, the total light transmittance in the present specification is set to a value measured in accordance with JIS K7361-1:1997.

(4) Manufacture of adhesive sheets

As a manufacturing example of the adhesive sheet 1, the coating layer is formed by applying the solventless adhesive composition P to the peeling surface of one of the release sheets 12a (or 12b), and the coating layer is superposed on the coating layer. After peeling off the peeling surface of the sheet 12b (or 12a), the coating layer is subjected to active energy ray irradiation and/or heat treatment to form the adhesive layer 11.

In another example of the production of the pressure-sensitive adhesive sheet 1, the solvent-free adhesive composition P is applied to the release surface of one of the release sheets 12a (or 12b), and subjected to active energy ray irradiation and/or heat treatment to obtain a solvent-free type. After the adhesive composition P is hardened to form the adhesive layer 11, the peeling surface of the other release sheet 12b (or 12a) is superposed on the adhesive layer 11.

As a method of applying the coating liquid of the solventless adhesive composition P, for example, a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method, or a gravure coating method can be used. Bufa and so on.

In the pressure-sensitive adhesive sheet 1 of the present embodiment, the pressure-sensitive adhesive layer 11 includes an adhesive which cures the solvent-free adhesive composition P, and thus has a very high cohesive force as described above. Further, when the coating film of the solventless adhesive composition P is formed, it is estimated that the organic alkoxysilane having a polarity is more likely to be in the vicinity of the surface of the coating film, and the condensation reaction proceeds more in the vicinity of the surface. As a result, in the adhesive sheet 1 of the present embodiment, it is estimated that the closer to the surface of the adhesive layer 11, the higher the cohesive force. According to the adhesive sheet 1 of the present embodiment, excellent foaming resistance can be exhibited.

[display body]

As shown in Fig. 2, the display body 2 of the present embodiment includes a first display member constituting member 21 (a display body constituting member) having a step on the side where the bonding is performed, and a second display constituting member. 22 (another display body constituent member); and an adhesive layer 11 located between the first display body constituent member 21 and the second display body constituent member 22. In the display 2 of the present embodiment, the first display member constituting member 21 has a step on the surface on the side of the adhesive layer 11, and specifically has a step formed by the printed layer 3.

The adhesive layer 11 in the display body 2 is the adhesive layer 11 of the adhesive sheet 1.

Examples of the display body 2 include a liquid crystal (LCD) display, a light-emitting diode (LED) display, an organic electroluminescence (organic EL) display, electronic paper, and the like, and may be a touch panel. Further, the display body 2 may be a member constituting a part of the components.

The first display member constituting member 21 may be a glass plate, a plastic plate or the like, and is preferably a protective panel including a laminate or the like. At this time, the printed layer 3 is generally formed in a frame shape on the side of the adhesive layer 11 in the first display body constituent member 21.

The glass plate is not particularly limited, and examples thereof include chemically strengthened glass, alkali-free glass, quartz glass, soda lime glass, bismuth/niobium-containing glass, aluminosilicate glass, lead glass, borosilicate glass, and bismuth boron. Citrate glass, etc. The thickness of the glass plate is not particularly limited, but is usually 0.1 mm or more and 0.2 mm or more. Further, the thickness is usually 5 mm or less, and 2 mm or less is preferable.

The plastic plate is not particularly limited, and for example, Ethylene plate, polycarbonate plate, etc. The thickness of the plastic plate is not particularly limited, but is usually 0.2 mm or more, and 0.4 mm or more is preferable. Further, the thickness is usually 5 mm or less, and preferably 3 mm or less.

Further, various functional layers (a transparent conductive film, a metal layer, a silicon oxide layer, a hard coat layer, an antiglare layer, etc.) may be provided on one or both sides of the glass plate or the plastic plate, or an optical member may be laminated. Also, the transparent conductive film and the metal layer can be patterned.

The second display body constituent member 22 is an optical member or a display body module to be attached to the first display body constituent member 21 (for example, a liquid crystal (LCD) module, a light emitting diode (LED) module, and an organic electroluminescence. A light-emitting (organic EL) module or the like, an optical member as a part of the display body module, or a laminated body including the display body module is preferable.

Examples of the optical member include a scattering preventing film, a polarizing plate (polarizing film), a polarizer, a phase difference plate (retardation film), a viewing angle compensation film, a brightness enhancement film, a contrast improving film, and a liquid crystal polymer film. A diffusion film, a transflective film, a transparent conductive film, or the like. As the scattering preventing film, a hard coat film obtained by forming a hard coat layer on one surface of a base film can be exemplified.

The material constituting the printed layer 3 is not particularly limited, and a known material for printing can be used. The thickness of the printed layer 3, that is, the height of the step is preferably 3 μm or more, more preferably 5 μm or more, further preferably 7 μm or more, and most preferably 10 μm or more. Further, the height is preferably 50 μm or less, and particularly preferably 35 μm or less.

When the display body 2 is manufactured, as an example, the adhesive sheet 1 is peeled off. In one peeling sheet 12a, 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 exists. Then, the other release sheet 12b is peeled off from the adhesive layer 11 of the adhesive sheet 1, and the exposed adhesive layer 11 of the adhesive sheet 1 is bonded to the second display member constituting member 22. Further, as another example, the order of bonding the first display body constituent member 21 and the second display body constituent member 22 may be replaced.

In the above display 2, it is estimated that since the adhesive layer 11 includes an adhesive obtained by hardening the above-described solvent-free adhesive composition P, it has a very high cohesive force as described above, in particular, closer to the adhesive layer 11 The surface, the higher the cohesion. Therefore, even if the display body 2 is placed under high temperature and high humidity conditions, air leakage occurs from the first display body constituent member 21 or the second display body constituent member 22, and generation of bubbles such as bubbles, floating, and peeling can be suppressed.

The embodiments described above are described in order to facilitate the understanding of the present invention, and are not intended to limit the present invention. Therefore, the various embodiments disclosed in the above embodiments are intended to encompass all design changes and equivalents of the technical scope of the invention.

For example, any one or both of the release sheets 12a, 12b in the adhesive sheet 1 may be omitted, and a desired optical member may be laminated instead of the release sheets 12a and/or 12b. Further, the first display body constituent member 21 may have a step other than the printed layer 3. Further, not only the first display body constituent member 21 but also the second display body constituent member 22 may have a step on the side of the adhesive layer 11.

[Examples]

Hereinafter, the present invention will be further specifically described by way of examples. It is to be understood that the scope of the invention is not limited to the embodiments.

[Manufacturing Example 1]

1. Preparation of urethane acrylate oligomers

By mixing 100 parts by mass of polypropylene glycol having a weight average molecular weight of 3000 (converted solid content; the same as below), 4 parts by mass of hexamethylene diisocyanate, and 0.02 parts by mass of dioctyltin dilaurate, and stirring at 80 ° C 6 The reaction was obtained in an hour. As a result of measuring the IR spectrum by the infrared spectroscopy of the obtained reactant, it was confirmed that the isocyanate group almost disappeared.

Then, 1 part by mass of 2-isocyanate ethyl acrylate was mixed with the total amount of the obtained reactant, and the mixture was stirred at 80 ° C for 3 hours to obtain a urethane acrylate oligomer. With respect to the obtained urethane acrylate oligomer, the IR spectrum was measured by infrared spectroscopy, and it was confirmed that the isocyanate group almost disappeared. Further, the molecular weight of the obtained urethane acrylate oligomer was measured by the method described later, and the weight average molecular weight (Mw) was 25,000.

2. Preparation of liquid mixture

40 parts by mass of 2-ethylhexyl acrylate as a polymerizable vinyl monomer, 20 parts by mass of isobornyl acrylate as a polymerizable vinyl monomer, and 2-hydroxy acrylate as a polymerizable vinyl monomer 10 parts by mass of the ethyl ester and 30 parts by mass of the urethane acrylate oligomer prepared as above as the polyfunctional (meth) acrylate oligomer were stirred to obtain a liquid mixture.

Here, the weight average molecular weight (Mw) is a polystyrene-equivalent weight average molecular weight measured by gel permeation chromatography (GPC) under the following conditions (GPC measurement).

<Measurement conditions>

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

‧GPC column (passed in the following order): TSK guard column made by TOSOH CORPORATION HXL-H TSK gel GMHXL (×2) TSK gel G2000HXL

‧ Determination of solvent: tetrahydrofuran

‧Measurement temperature: 40 ° C

[Manufacturing Example 2]

40 parts by mass of 2-ethylhexyl acrylate as a polymerizable vinyl monomer, 20 parts by mass of propylene morpholine as a polymerizable vinyl monomer, and 2-hydroxy acrylate as a polymerizable vinyl monomer 10 parts by mass of the ethyl ester and 30 parts by mass of the urethane acrylate-based oligomer prepared in the above Production Example 1 were stirred to obtain a liquid mixture.

[Example 1]

1. Preparation of solvent-free adhesive composition

100 parts by mass of the liquid mixture prepared in the above Production Example 1 (solid content conversion value; the same applies hereinafter), 1,6-bis(trimethoxydecyl)hexane 0.3 as the organoalkoxydecane. A solvent-free adhesive composition was obtained in parts by mass and 0.5 parts by mass of 1-hydroxy-cyclohexyl-phenyl-ketone as a photopolymerization initiator.

2. Manufacture of adhesive sheets

A heavy peeling release sheet obtained by peeling one side of a polyethylene terephthalate film with an anthrone-based release agent (LINTEC Corporation) The solvent-free adhesive composition obtained in the above Process 1 was applied by a doctor blade coater on the release-treated surface of the product name "SP-PET752150".

Then, the coating layer on the heavy release release sheet obtained above and the one side of the polyethylene terephthalate film were subjected to a release treatment by a decyl ketone release agent (manufactured by LINTEC Corporation). The product name "SP-PET382120" was bonded so that the peeling-treated surface of the light-peelable release sheet was in contact with the coating layer.

Then, the coating layer was irradiated with ultraviolet rays under the following conditions through a heavy release type release sheet to prepare an adhesive sheet having a structure of a heavy release type release sheet/adhesive layer (thickness: 100 μm)/light release type release sheet.

[UV irradiation conditions]

‧Light source: high pressure mercury lamp

‧Light quantity: 1000mJ/cm ²

‧ Illuminance: 100mW/cm ²

[Examples 2 to 4, Comparative Examples 1 to 6]

An adhesive sheet was produced in the same manner as in Example 1 except that the type of the liquid mixture and the type and amount of the organoalkoxydecane were changed as shown in Table 1. Further, in Comparative Example 3, tris-(trimethoxymercaptopropyl)isocyanurate used as the organoalkoxydecane is a so-called isocyanurate ring as a main skeleton and the main skeleton or the like. There are three trimethoxymercaptopropyl groups bonded to each other. Therefore, the organoalkoxydecane cannot be said to be the above-mentioned organoalkoxydecane having a linear structure, and is not equivalent to the organoalkoxydecane of the present embodiment.

[Test Example 1] (Measurement of gel fraction)

The adhesive sheets obtained in the examples and the comparative examples were cut into 80 mm×80 mm. The size of the adhesive is wrapped in a polyester mesh (mesh size 200), and the quality of the adhesive itself is calculated by weighing the mass by a precision balance and subtracting the individual mass of the mesh. Set the quality at this time to M1.

Next, the adhesive wrapped in the above polyester web was immersed in ethyl acetate for 3 days at room temperature (23 ° C). Thereafter, the adhesive was taken out and dried in an oven at 100 ° C for 3 hours. After drying, after standing for 3 hours in an environment of a temperature of 23 ° C and a relative humidity of 50%, the quality of the adhesive itself was calculated by weighing the mass by a precision balance and subtracting the individual mass of the above net. Set the quality at this time to M2. The gel fraction (%) is represented by (M2/M1) × 100. The results are shown in Table 1.

[Test Example 2] (Evaluation of optical characteristics)

The light-peelable release sheet was peeled off from the adhesive sheets obtained in the examples and the comparative examples, and the exposed adhesive layer was attached to a soda lime glass (manufactured by Nippon Sheet Glass Company, Ltd.) having a thickness of 1.1 mm, and then peeled off. A peel-off type release sheet was obtained, whereby a sample for evaluation was obtained.

The measurement light of a haze meter (manufactured by NIPPON DENSHOKU INDUSTRIES CO., LTD., product name "NDH-2000") was incident on the adhesive layer side of the evaluation sample, and total light transmittance (%) and haze were measured. value(%). The measurement was performed three times, and the average value of the values was calculated. The results are shown in Table 1.

[Test Example 3] (Measurement of adhesion)

The light release release sheet was peeled off from the adhesive sheets obtained in the examples and the comparative examples, and the exposed adhesive layer was attached to a polyethylene terephthalate (PET) film having an easy adhesion layer (TOYOBO CO.). , LTD., product name "PET A4300", thickness: 100μm) easy adhesion layer, thus obtaining release sheet / adhesive Layer/PET film laminate. The obtained laminate was cut into a width of 25 mm and a length of 150 mm, and this was used as a sample.

The peeling release sheet was peeled off from the above sample in an environment of 23° C. and 50% RH, and the exposed adhesive layer was attached to soda lime glass (manufactured by Nippon Sheet Glass Co., Ltd.), and 2 kg was used. The roller is reciprocated once to crimp. Then, it was allowed to stand under the conditions of 23 ° C and 50% RH for 24 hours, and then measured under the conditions of a peeling speed of 300 mm/min and a peeling angle of 180 degrees using a tensile tester (Tensilon, manufactured by ORIENTEC CO., LTD.). Adhesion (N/25mm). Conditions other than those described herein were measured in accordance with JIS Z0237:2009. The results are shown in Table 1.

[Test Example 4] (Evaluation of blister resistance)

The light release release sheet of the adhesive sheet obtained in the examples and the comparative examples was peeled off, and the exposed adhesive layer was attached to a polyethylene terephthalate film (manufactured by Oike & Co., Ltd., product name). ITO film ", thickness: 125 μm) provided with a transparent conductive film surface, the polyethylene terephthalate film is provided with a transparent conductive film including tin-doped indium oxide (ITO) on one side, and cut into 60 mm × 60mm. In addition, the heavy release type release sheet was peeled off from the adhesive sheet, and the exposed adhesive layer was attached to a resin plate (made by Mitsubishi Gas Chemical Co., Ltd.) in which polymethyl methacrylate (PMMA) and polycarbonate (PC) were laminated. A test piece was obtained by the surface of the polycarbonate side of the product name "MR-58", thickness: 785 μm).

The obtained test piece was treated in an autoclave at 50 ° C and 0.5 MPa for 30 minutes, and then left under normal pressure at 23 ° C and 50% RH for 24 hours. Next, it was stored under high temperature and high humidity conditions of 85 ° C and 85% RH for 72 hours. Then, visually confirm the floating peeling at the interface between the adhesive layer and the adherend, and benefit The foaming resistance was evaluated by the following criteria. The results are shown in Table 1.

○: Bubbles and floating peeling could not be confirmed.

△: A small amount of small bubbles were confirmed, but floating peeling was not confirmed.

×: A large bubble or floating peeling was confirmed.

[Test Example 5] (Evaluation of resistance to wet heat whitening)

A polyethylene terephthalate film (manufactured by Oike & Co., Ltd., product name "ITO film", thickness: 125 μm) provided with a transparent conductive film containing tin-doped indium oxide (ITO) on one side. The adhesive layer of the adhesive sheet obtained in the Example or the comparative example was clamped, and the laminated body was obtained. At this time, the surface of the film provided with the transparent conductive film was attached to the adhesive layer. The obtained laminate was autoclaved for 30 minutes at 50 ° C and 0.5 MPa, and then left under normal pressure at 23 ° C and 50% RH for 24 hours. Then, a haze value (%) was measured in accordance with JIS K7136:2000 using a haze meter (manufactured by NIPPON DENSHOKU INDUSTRIES CO., LTD., product name "NDH2000").

Next, the laminate was stored under humid heat conditions of 85 ° C and 85% RH for 120 hours (endurance test). Then, the temperature was normalized to normal temperature of 23 ° C and 50% RH, and the haze value (%) was measured again for the laminate. In addition, the haze value was measured within 30 minutes after returning the layered body to normal temperature and normal humidity.

From the haze value (%) before the endurance test to the rise value of the haze value (%) after the endurance test, the wet heat resistance was evaluated based on the following criteria. The results are shown in Table 1.

◎: The rise value of the haze value (%) after the endurance test was 0.90% or less.

○: The rise value of the haze value (%) after the endurance test exceeded 0.90% and 1.50% or less.

×: The rise value of the haze value (%) after the endurance test exceeded 1.50%.

[Test Example 6] (Evaluation of the step followability)

In the glass plate (manufactured by NSG Precision Co., Ltd., product name "Corning glass Eagle XG", vertical 90 mm × width 50 mm × thickness 0.5 mm), the coating thickness was 30 μm, and the shape was framed (shape: Screen printing UV-curable ink (manufactured by Teikoku Printing Inks Mfg. Co., Ltd., product name "POS-911 Ink"), 90 mm in length × 50 mm in width, and 5 mm in width). Next, ultraviolet rays (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 irradiated to cure the above-mentioned ultraviolet curable ink printed, thereby producing a belt having a step formed by printing. The step glass plate.

The light release release sheet was peeled off from the adhesive sheets obtained in the examples and the comparative examples, and the exposed adhesive layer was attached to a polyethylene terephthalate film having an easy adhesion layer (TOYOBO Co., Ltd. The easy-to-layer layer of the product name "PET A4300", thickness: 100 μm). Next, the heavy release type release sheet was peeled off to expose the adhesive layer. Further, a plastic laminator (product name "LPD3214" manufactured by FUJIPLA Inc.) was used, and the exposed surface of the adhesive layer and the glass plate having the difference of the step were covered with the adhesive layer covering the entire printing surface of the frame. This was used as a sample for evaluation.

The obtained sample for evaluation was subjected to an autoclave treatment at 50 ° C and 0.5 MPa for 30 minutes, and then left at normal pressure, 23 ° C, and 50% RH for 24 hours. Subsequently, it was stored under high temperature and high humidity conditions of 85 ° C and 85% RH for 72 hours (endurance test), and then the adhesive layer (especially in the vicinity of the step generated by the printed layer) was visually confirmed, and evaluated by the following criteria. The step difference follows. The results are shown in Table 1.

◎: There was no floating peeling near the step, and the adhesive followed in a gapless manner.

○: A slight floating peeling was observed in the vicinity of the step.

×: Large bubbles are mixed in the vicinity of the step.

As is clear from Table 1, the pressure-sensitive adhesive sheets obtained in the examples were excellent in foaming resistance, and also excellent in wet heat whitening resistance and step followability.

[Industrial availability]

The solventless adhesive composition, the adhesive, and the adhesive sheet of the present invention can be preferably used, for example, for bonding a display constituent member.

1‧‧‧Adhesive film

11‧‧‧Adhesive layer

12a, 12b‧‧‧ peeling film

Claims (10)

A solventless adhesive composition characterized by comprising: a polymerizable vinyl monomer, a polymerizable vinyl prepolymer, a polyfunctional (meth) acrylate monomer, and a polyfunctional (meth) acrylate At least one of the polymerization components of the oligomer; and the organoalkoxydecane having a linear structure and having an alkoxyfluorenyl group at both ends thereof, and at least a part of the polymerization component contains an active hydrogen group. The solventless adhesive composition according to claim 1, wherein the active hydrogen group is a hydroxyl group. The solvent-free adhesive composition according to claim 1, wherein the solvent-free adhesive composition contains at least the polymerizable vinyl monomer and the polyfunctional (meth) acrylate oligomer as The aforementioned polymerization component. The solvent-free adhesive composition according to claim 1, wherein the solvent-free adhesive composition further contains a photopolymerization initiator. The solvent-free adhesive composition according to the first aspect of the invention, wherein the content of the organoalkoxydecane in the solvent-free adhesive composition is 0.01 parts by mass or more based on 100 parts by mass of the polymerization component. And 20 parts by mass or less. An adhesive which is obtained by hardening a solventless adhesive composition according to item 1 of the patent application. The adhesive according to claim 6, wherein the adhesive has a gel fraction of 50% or more and 100% or less. An adhesive sheet having an adhesive layer formed of the adhesive described in claim 6 of the patent application. The adhesive sheet according to claim 8, wherein the adhesive sheet comprises two release sheets, and the adhesive layer is sandwiched by the release sheet so as to be in contact with the peeling surface of the two release sheets. A display body comprising: a display body constituting member having a step at least on a surface to be attached; another display body constituting member; an adhesive layer affixing to each other to form a display body constituting member and the other display body The member is characterized in that the adhesive layer is an adhesive layer of the adhesive sheet according to claim 8 of the patent application.