JP6894686B2 - Adhesive Compositions, Adhesives, Adhesive Sheets and Labels - Google Patents

Description

The present invention relates to an adhesive composition, an adhesive, an adhesive sheet and a display manufactured by using them, and an adhesive and an adhesive, which are suitable for adhering display body constituent members. It relates to a method of manufacturing a wearing sheet and a display body.

In recent years, various mobile electronic devices such as smartphones and tablet terminals are provided with a display using a display module having a liquid crystal element, a light emitting diode (LED element), an organic electroluminescence (organic EL) element, and the like. It is becoming more and more popular as a touch panel.

In a display as described above, a protective panel is usually provided on the surface side of the display module. With the thinning and weight reduction of electronic devices, the protective panel has been changed from a conventional glass plate to a plastic plate such as an acrylic plate or a polycarbonate plate.

Here, a gap is provided between the protective panel and the display module so that the deformed protective panel does not collide with the display module even when the protective panel is deformed by an external force.

However, in the presence of the above-mentioned voids, that is, the air layer, the light reflection loss due to the difference in the refractive index between the protective panel and the air layer and the difference in the refractive index between the air layer and the display module is large, and the display has a large return loss. There is a problem that the image quality is deteriorated.

Therefore, it has been proposed to improve the image quality of the display by filling the gap between the protective panel and the display module with an adhesive layer. However, a frame-shaped print layer may exist as a step on the display module side of the protective panel. If the pressure-sensitive adhesive layer does not follow the step, the pressure-sensitive adhesive layer floats in the vicinity of the step, which causes a loss of light reflection. Therefore, the pressure-sensitive adhesive layer is required to have a step-following property.

In order to solve the above problems, Patent Document 1 has a shear storage elastic modulus (G') of 1.0 at 25 ° C. and 1 Hz as an adhesive layer that fills the gap between the protective panel and the display module. A pressure-sensitive adhesive layer having a gel content of × 10 ⁵ Pa or less and a gel content of 40% or more is disclosed.

In the invention disclosed in Patent Document 1, the step followability is improved by lowering the storage elastic modulus (G') of the pressure-sensitive adhesive layer at room temperature. However, if the storage elastic modulus (G') at room temperature is lowered as described above, the storage elastic modulus (G') at high temperature is lowered more than necessary, and a problem occurs under durable conditions. For example, when high temperature and high humidity conditions are applied, air bubbles are generated in the vicinity of the step, or outgas is generated from the plastic plate which is a protective panel, and blisters such as air bubbles, floating, and peeling are generated. On the other hand, if the adhesive layer is hardened in order to improve the blister resistance, the step followability is lowered.

Further, Patent Document 2 proposes a pressure-sensitive adhesive film having improved step-following property, in which a radically polymerizable composition and a cationically polymerizable composition are mixed and the cured state of the pressure-sensitive adhesive is controlled by ultraviolet rays (UV). doing. Specifically, using a UV lamp illumination 1~10mW / cm ² to maintain the semi-cured state by the primary crosslinking reaction of the radical polymerizable composition, the UV lamp illumination 50~150mW / cm ² at the time of use It is used to carry out a complete curing reaction by a secondary cross-linking reaction of the cationically polymerizable composition.

JP-A-2010-97070 Special Table 2015-515527

However, in the invention described in Patent Document 2, the productivity is low because the UV illuminance at the time of the primary cross-linking is weak, and the reaction proceeds not only with the radical-polymerizable compound but also with some cationically polymerizable compounds at the time of the primary cross-linking. Therefore, there is a risk that the secondary cross-linking will not proceed sufficiently. Then, sufficient blister resistance cannot be obtained.

The present invention has been made in view of such an actual situation, and is an adhesive composition, an adhesive, an adhesive sheet and a display body, and a step, which are excellent in both step-following property and blister resistance. It is an object of the present invention to provide a method for producing an adhesive adhesive, an adhesive sheet and a display body having excellent followability and blister resistance.

In order to achieve the above object, firstly, the present invention comprises a radically polymerizable component (A), an ionic polymerizable component (B), and a visible light-activated radical polymerization initiator (C) activated by visible light. And an ultraviolet-activated ion polymerization initiator (D) that is activated by ultraviolet rays are provided (Invention 1).

When the coating film of the adhesive composition according to the above invention (Invention 1) is irradiated with visible light, the visible light-activated radical polymerization initiator (C) is activated to generate radicals, which are radically polymerizable components. The polymer of (A) is formed. At this time, since the ion-polymerizable component (B) does not polymerize, a semi-cured adhesive layer can be obtained. This semi-cured adhesive layer is excellent in initial step followability. Further, when one display body constituent member and another display body component are bonded to each other via the adhesive layer and then irradiated with ultraviolet rays, the ultraviolet activated ion polymerization initiator (D) is activated to form ions. Is generated, a polymer of the ion-polymerizable component (B) is formed, and the adhesive layer is cured to become an adhesive layer after curing. This cured adhesive layer is excellent in step followability and blister resistance under high temperature and high humidity conditions.

In the above invention (Invention 1), the radically polymerizable component (A) is at least a (meth) acryloyl group-containing monomer having a (meth) acryloyl group in the molecule and a vinyl group-containing monomer having a vinyl group in the molecule. It is preferable to include one type (Invention 2).

In the above inventions (Inventions 1 and 2), it is preferable that the radically polymerizable component (A) contains a urethane oligomer having a radically polymerizable group (Invention 3).

In the above inventions (Inventions 1 to 3), it is preferable that the ion-polymerizable component (B) contains a compound having an epoxy group or a glycidyl ether group (Invention 4).

In the above inventions (Inventions 1 to 4), it is preferable that the adhesive composition is a solvent-free adhesive composition (Invention 5).

Secondly, the present invention is characterized in that the radical polymerizable component (A) is polymerized to obtain an adhesive by irradiating the adhesive composition (Invention 1 to 5) with visible light. (Invention 6).

Thirdly, the present invention contains a polymer derived from a radically polymerizable component (A), an ionic polymerizable component (B), and an ultraviolet activated ion polymerization initiator (D) that is activated by ultraviolet rays. Provided is a characteristic adhesive adhesive (Invention 7).

Fourth, the present invention provides an adhesive sheet having an adhesive layer made of the adhesive (Invention 7) (Invention 8).

In the above invention (Invention 8), the adhesive sheet includes two release sheets, and the release sheet is in contact with the release surface of the two release sheets. It is preferable that it is sandwiched between the two (Invention 9).

Fifth, the present invention is a method for producing a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer, wherein the pressure-sensitive adhesive composition (Invention 1 to 5) is applied to the pressure-sensitive adhesive composition. (Invention 10), the present invention provides a method for producing an adhesive sheet, which comprises polymerizing the radically polymerizable component (A) to form an adhesive layer by irradiating the coating film with visible light. ..

Sixth, the present invention has a cured adhesive layer that adheres one display body component, another display body component, the one display body component, and the other display body component to each other. After curing, the post-curing adhesive layer contains a polymer derived from the radically polymerizable component (A) and a polymer derived from the ionic polymerizable component (B). Provided is a display body made of an adhesive adhesive (Invention 11).

Seventh, the present invention is a laminated body formed by laminating one display body component and another display body component via an adhesive layer of the adhesive sheet (Invention 8 and 9). Is produced, the adhesive layer of the laminate is irradiated with ultraviolet rays, and the ion-polymerizable component (B) is polymerized to form an adhesive layer after curing. (Invention 12).

The adhesive composition, adhesive, adhesive sheet and display according to the present invention are excellent in both step followability and blister resistance.

It is sectional drawing of the adhesive sheet which concerns on one Embodiment of this invention. It is sectional drawing of the laminated body which concerns on one Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described.
[Adhesive composition]
The adhesive composition according to the present embodiment (hereinafter, may be referred to as “adhesive composition P”) includes a radically polymerizable component (A), an ionic polymerizable component (B), and visible light. It contains a visible light-activated radical polymerization initiator (C) activated by, and an ultraviolet-activated ion polymerization initiator (D) activated by ultraviolet rays. Here, the "adhesive adhesive" refers to an adhesive that exhibits adhesiveness in an initial state and is cured by a trigger such as ultraviolet irradiation to exhibit strong adhesiveness. Further, the visible light in the present specification means a light having a wavelength of 380 nm or more and 780 nm or less, and the ultraviolet ray means a light having a wavelength of 10 nm or more and less than 380 nm.

When the coating film of the adhesive composition P is irradiated with visible light, the visible light-activating radical polymerization initiator (C) is activated to generate radicals. As a result, the radically polymerizable component (A) is radically polymerized, and a polymer of the radically polymerizable component (A) is formed in the composition. At this time, since the ion-polymerizable component (B) does not polymerize, a semi-cured adhesive layer can be obtained. Even when the semi-cured adhesive layer is attached to a display body component having a step, it easily follows the step, and it is possible to prevent gaps, floats, etc. from occurring in the vicinity of the step. Therefore, the adhesive layer formed by the adhesive composition P is excellent in initial step followability.

Further, after the one display body component and the other display body component are bonded to each other via the adhesive layer, the adhesive layer is passed through the one display body component or the other display body component. When the ultraviolet rays are irradiated to the ultraviolet rays, the ultraviolet-activated ion polymerization initiator (D) is activated to generate ions. As a result, the ionic polymerizable component (B) is ion-polymerized, a polymer of the ionic polymerizable component (B) is formed in the adhesive, and the adhesive layer is cured. Become a layer. Since this cured adhesive layer exhibits high cohesive force and strong adhesiveness, the obtained laminate (display body) is subjected to 72 under high temperature and high humidity conditions, for example, 85 ° C. and 85% RH conditions. Even after a long time, bubbles, floats, peeling, etc. are suppressed in the vicinity of the step. Further, the generation of blisters such as air bubbles, floating, and peeling at the interface between the display body component and the cured adhesive layer is suppressed. Therefore, the adhesive layer formed by the adhesive composition P, and thus the adhesive layer after curing, is excellent in step followability and blister resistance under high temperature and high humidity conditions.

Here, in the adhesive composition P according to the present embodiment, the visible light-activated radical polymerization initiator (C) and the ultraviolet-activated ion polymerization initiator (D) are individually present. As a result, when irradiating the coating film of the adhesive composition P with visible light, it is not necessary to lower the illuminance of the visible light, and the ionic polymerizable component (B) is cured by the visible light irradiation. Therefore, the ion-polymerizable component (B) is sufficiently cured by the subsequent irradiation with ultraviolet rays, and a desired adhesiveness can be obtained. Therefore, according to the adhesive composition P, it is possible to produce a display body having excellent step followability and blister resistance with high productivity.

The adhesive composition P according to the present embodiment is preferably a solvent-free adhesive composition, and having the above composition enables a solvent-free type. The solvent-free adhesive composition can be mixed and coated without using a solvent, and does not require a solvent volatilization step, so that a thick adhesive layer can be easily formed. Can be formed.

(1) Each component (1-1) Radical polymerizable component (A)
The radically polymerizable component (A) in the present embodiment is preferably a component that undergoes radical polymerization by radicals generated by the visible light-activated radical polymerization initiator (C) and exhibits a predetermined adhesiveness. The radically polymerizable component (A) preferably contains at least one (meth) acryloyl group-containing monomer having a (meth) acryloyl group in the molecule and a vinyl group-containing monomer having a vinyl group in the molecule. It is also preferable to contain a urethane oligomer having a radically polymerizable group (polymerizable urethane oligomer), and in particular, it may contain at least one of a (meth) acryloyl group-containing monomer and a vinyl group-containing monomer, and a polymerizable urethane oligomer. preferable. Here, it is assumed that the vinyl group-containing monomer does not contain the (meth) acryloyl group-containing monomer. In addition, in this specification, (meth) acryloyl means both acryloyl and meta-acryloyl. The same applies to other similar terms.

The (meth) acryloyl group-containing monomer and the vinyl group-containing monomer are preferably used because they undergo radical polymerization and exhibit predetermined adhesiveness. Further, since the (meth) acryloyl group-containing monomer and the vinyl group-containing monomer have a relatively small molecular weight and a low viscosity, by using these, the adhesive composition P does not require a solvent. It can be mixed, coated, etc., and can be a solvent-free adhesive composition.

The (meth) acryloyl group-containing monomer may be a monofunctional (meth) acryloyl group-containing monomer or a polyfunctional (meth) acryloyl group-containing monomer. Here, the monofunctional (meth) acryloyl group-containing monomer means a monomer having one (meth) acryloyl group in the molecule, and the polyfunctional (meth) acryloyl group-containing monomer means the (meth) acryloyl group-containing monomer in the molecule. ) A monomer having two or more acryloyl groups. The (meth) acryloyl group-containing monomer may be used alone or in combination of two or more.

As the monofunctional (meth) acryloyl group-containing monomer, for example, a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 20 carbon atoms is preferably mentioned. Examples of the (meth) acrylic acid alkyl ester having an alkyl group having 1 to 20 carbon atoms include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, and pentyl (meth). Acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, myristyl (meth) acrylate, palmityl (meth) acrylate, stearyl (meth) Examples thereof include acrylate and lauryl (meth) acrylate. Among these, (meth) acrylic acid alkyl esters having an alkyl group having 1 to 8 carbon atoms are preferable, and 2-ethylhexyl acrylate is particularly preferable from the viewpoint of exhibiting high adhesive strength to various adherends.

Further, as the monofunctional (meth) acryloyl group-containing monomer, (meth) acrylate having an alicyclic structure in the molecule (alicyclic structure-containing (meth) acrylate) is also preferably mentioned. Since the alicyclic structure-containing (meth) acrylate has a bulky alicyclic structure and exhibits hydrophobicity, the adhesiveness of the obtained adhesive adhesive to the resin plate is increased, and thus the blister resistance is improved.

Examples of the alicyclic structure-containing (meth) acrylate include cyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, adamantyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentenyl (meth) acrylate, and dicyclopentenyl (meth) acrylate. Cyclopentenyloxyethyl (meth) acrylate and the like can be mentioned. Among these, isobornyl acrylate is preferable from the viewpoint of adjusting the viscosity of the coating liquid and radically polymerizable.

The monofunctional (meth) acryloyl group-containing monomer may have a reactive group. Examples of the reactive group include a hydroxy group, a carboxy group, a thiol group, and a primary or secondary amino group. Examples of the monofunctional (meth) acryloyl group-containing monomer having such a reactive group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 3-hydroxypropyl (meth) acrylate. Hydroxyalkyl (meth) acrylates such as 2-hydroxybutyl (meth) acrylates, 3-hydroxybutyl (meth) acrylates and 4-hydroxybutyl (meth) acrylates; Acrylamides; ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, and citraconic acid can be mentioned.

Among the above, when hydroxyalkyl (meth) acrylate is used, a predetermined amount of hydroxy groups are present in the obtained adhesive adhesive. Hydroxy groups are hydrophilic groups, and when a predetermined amount of such hydrophilic groups is present in the adhesive, even when the adhesive is placed under high temperature and high humidity conditions, the high temperature and high humidity conditions thereof. The compatibility with the moisture infiltrated into the adhesive is good, and as a result, the whitening of the adhesive when the temperature is returned to normal temperature and humidity is suppressed (excellent in moisture-heat whitening resistance). From this point of view, it is preferable to use a hydroxyalkyl (meth) acrylate, and in particular, a hydroxyalkyl (meth) acrylate having a hydroxyalkyl group having 1 to 4 carbon atoms is preferably used, and further, 2-hydroxyethyl It is preferable to use acrylate.

In addition to the above, examples of the monofunctional (meth) acryloyl group-containing monomer include alkoxyalkyl (meth) acrylates such as methoxyethyl (meth) acrylate and ethoxyethyl (meth) acrylate; and polyoxyalkylene-modified (meth) acrylate. Nitrigen-based monomers such as acryloyl nitrile and methacryl nitrile; acrylamide, methacrylic amide, N-methyl acrylamide, N-methyl methacrylic amide, NN-dimethyl (meth) acrylamide, NN-diethyl (meth) acrylamide, etc. Amid-based monomer; A tertiary amino group-containing monomer such as NN-diethylaminoethyl (meth) acrylate and N- (meth) acryloylmorpholin can also be used.

As the polyfunctional (meth) acryloyl group-containing monomer, a monomer having two or more (meth) acryloyl groups in one molecule can be preferably mentioned. Examples of such monomers include 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, and the like. Neopentyl glycol adipate di (meth) acrylate, neopentyl glycol di (meth) acrylate of hydroxypivalate, dicyclopentanyl di (meth) acrylate, caprolactone-modified dicyclopentenyl di (meth) acrylate, ethylene oxide-modified di (meth) phosphate ) Acrylate, di (acryloxyethyl) isocyanurate, allylated cyclohexyldi (meth) acrylate, trimethylpropanthry (meth) acrylate, dipentaerythritol tri (meth) acrylate, propionic acid-modified dipentaerythritol tri (meth) acrylate , Pentaerythritol tri (meth) acrylate, propylene oxide modified trimethylolpropantri (meth) acrylate, tris (acryloxyethyl) isocyanurate, bis (acryloxyethyl) hydroxyethyl isocyanurate, isocyanurate ethylene oxide modified diacrylate, isocyanul Ethylene oxide-modified triacrylate, ε-caprolactone-modified tris (acryloxyethyl) isocyanurate, diglycerin tetra (meth) acrylate, pentaerythritol tetra (meth) acrylate, propionic acid-modified dipentaerythritol penta (meth) acrylate, dipenta Examples thereof include erythritol hexa (meth) acrylate and caprolactone-modified dipentaerythritol hexa (meth) acrylate.

Examples of the vinyl group-containing 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; styrene, α-methylstyrene and the like. Styrene-based monomers; diene-based monomers such as butadiene, isoprene, and chloroprene; amide-based monomers such as N-vinylpyrrolidone, and the like. These may be used individually by 1 type, and may be used in combination of 2 or more type.

The polymerizable urethane oligomer is preferably used because it undergoes radical polymerization and exhibits a predetermined adhesiveness. Further, the reactive urethane oligomer is particularly preferably used because it has an advantage that the viscosity of the coating liquid can be adjusted to the extent that thick film processing is possible.

The polymerization average molecular weight of the polymerizable urethane oligomer is preferably 3,000 or more, particularly preferably 5,000 or more, and further preferably 8,000 or more. The weight average molecular weight is preferably 100,000 or less, particularly preferably 50,000 or less, and further preferably 20,000 or less. The weight average molecular weight in the present specification is a standard polystyrene-equivalent value measured by a gel permeation chromatography (GPC) method.

The polymerizable urethane oligomer is preferably polyfunctional, and the polymerizable group of the polymerizable urethane oligomer is preferably present at the ends, particularly at both ends. As the type of the polymerizable group, for example, a (meth) acryloyl group, a vinyl group and the like are preferable, and a (meth) acryloyl group is particularly preferable. That is, the polymerizable urethane oligomer is preferably a polyfunctional (meth) acrylate oligomer, in other words, a urethane acrylate-based oligomer. The urethane acrylate-based oligomer can be radically polymerized together with the above-mentioned (meth) acryloyl group-containing monomer or vinyl group-containing monomer to exhibit preferable adhesiveness.

The urethane acrylate-based oligomer is a polyurethane oligomer obtained by reacting a compound such as a polyalkylene polyol, a polyether polyol, a polyester polyol, a hydrogenated isoprene having a hydroxy group terminal, or a hydrogenated butadiene having a hydroxy group end with a polyisocyanate. Can be obtained by esterifying with (meth) acrylic acid or (meth) acrylic acid derivative.

Here, examples of the polyalkylene polyol used for producing the urethane acrylate-based oligomer include polypropylene glycol, polyethylene glycol, polybutylene glycol, polyhexylene glycol and the like, and polypropylene glycol is particularly preferable. When the number of functional groups of the obtained urethane acrylate-based oligomer is 3 or more, glycerin, trimethylolpropane, triethanolamine, pentaerythritol, ethylenediamine, diethylenetriamine, sorbitol, sucrose and the like may be appropriately combined.

Examples of polyisocyanates include aliphatic diisocyanates such as hexamethylene diisocyanate and trimethylene diisocyanate; aromatic diisocyanates such as tolylene diisocyanate, xylylene diisocyanate and diphenyl diisocyanate; alicyclic diisocyanates such as dicyclohexylmethane diisocyanate and isophorone diisocyanate. Among these, it is preferable to use an alicyclic diisocyanate, and it is particularly preferable to use dicyclohexylmethane diisocyanate. Since the alicyclic structure is bulky and has low polarity, the blister resistance of the obtained adhesive adhesive is more excellent by using a urethane acrylate-based oligomer containing an alicyclic structure derived from an alicyclic diisocyanate. It becomes a thing. Further, by using dicyclohexylmethane diisocyanate, the chemical structure of the obtained urethane acrylate-based oligomer becomes similar to the chemical structure of glycidyl ethers preferable as the ion-polymerizable component (B) described later, and the compatibility is good. Become. The polyisocyanate is not limited to bifunctional ones, and trifunctional or higher functional ones can also be used.

Examples of the (meth) acrylic acid derivative include hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl acrylate and 4-hydroxybutyl acrylate, 2-isocyanatoethyl acrylate, 2-isocyanatoethyl methacrylate, and 1,1-bis. Examples thereof include (acryloxymethyl) ethyl isocyanate, and it is particularly preferable to use 2-isocyanatoethyl acrylate.

As another method for producing a urethane acrylate-based oligomer, a hydroxy group contained in a compound such as a polyalkylene polyol, a polyether polyol, a polyester polyol, a hydrogenated isoprene having a hydroxy group terminal, and a hydrogenated butadiene having a hydroxy group terminal, and an isocyanatoalkyl Urethane acrylate-based oligomers can also be obtained by the reaction between the (meth) acrylate and the -N = C = O moiety. In this case, as the isocyanatoalkyl (meth) acrylate, the above-mentioned 2-isocyanatoethyl acrylate, 2-isocyanatoethyl methacrylate, 1,1-bis (acryloxymethyl) ethyl isocyanate and the like can be used.

The radically polymerizable component (A) in the present embodiment may contain a polyfunctional (meth) acrylate oligomer other than the urethane acrylate-based oligomer in place of the urethane acrylate-based oligomer or together with the urethane acrylate-based oligomer. Examples of such oligomers include oligomers such as polyester acrylate-based, epoxy acrylate-based, polyether acrylate-based, polybutadiene acrylate-based, and silicone acrylate-based oligomers.

The polyester acrylate-based oligomer can be obtained, for example, by esterifying the hydroxy group of a polyester oligomer having hydroxy groups at both ends obtained by condensation of a polyvalent carboxylic acid and a polyhydric alcohol with (meth) acrylic acid, or by polyvalent. It can be obtained by esterifying the hydroxy group at the end of the oligomer obtained by adding an alkylene oxide to a carboxylic acid with (meth) acrylic acid.

The epoxy acrylate-based oligomer can be obtained, for example, by reacting (meth) acrylic acid with the oxylan ring of a bisphenol type epoxy resin or a novolak type epoxy resin having a relatively low molecular weight to esterify it. Further, a carboxyl-modified epoxy acrylate-based oligomer in which the epoxy acrylate-based oligomer is partially modified with a dibasic carboxylic acid anhydride can also be used.

The polyether acrylate-based oligomer can be obtained, for example, by esterifying the hydroxy group of the polyether polyol with (meth) acrylic acid.

The weight average molecular weight of the polyfunctional (meth) acrylate oligomer is preferably 1,000 or more, and particularly preferably 5,000 or more. The weight average molecular weight is preferably 100,000 or less, and particularly preferably 50,000 or less.

Among the above, the radically polymerizable component (A) in the present embodiment contains a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 20 carbon atoms, an alicyclic structure-containing (meth) acrylate, and a reactive group. It is preferable to contain a (meth) acryloyl group-containing monomer having a (meth) acryloyl group and a polymerizable urethane oligomer, and in particular, 2-ethylhexyl acrylate, isobornyl acrylate, 2-hydroxyethyl acrylate, and urethane acrylate-based oligomer. It is preferable to contain it from the viewpoint of compatibility of various materials.

In this case, the content of the (meth) acrylic acid alkyl ester (particularly 2-ethylhexyl acrylate) in the radically polymerizable component (A) is preferably 5% by mass or more, preferably 10% by mass or more, as the lower limit. It is more preferable to have it, and it is particularly preferable that it is 30% by mass or more. Further, the upper limit value is preferably 70% by mass or less, more preferably 60% by mass or less, and particularly preferably 50% by mass or less.

The content of the alicyclic structure-containing (meth) acrylate (particularly isobornyl acrylate) in the radically polymerizable component (A) is preferably 5% by mass or more, preferably 10% by mass or more, as the lower limit. It is more preferable, and it is particularly preferable that it is 15% by mass or more. Further, the upper limit value is preferably 50% by mass or less, more preferably 40% by mass or less, and particularly preferably 30% by mass or less.

The content of the (meth) acryloyl group-containing monomer (particularly 2-hydroxyethyl acrylate) having a reactive group in the radically polymerizable component (A) is preferably 2% by mass or more as the lower limit. It is more preferably mass% or more, and particularly preferably 8 mass% or more. The upper limit is preferably 40% by mass or less, more preferably 30% by mass or less, and particularly preferably 20% by mass or less.

The content of the polymerizable urethane oligomer (particularly urethane acrylate-based oligomer) in the radically polymerizable component (A) is preferably 5% by mass or more, more preferably 10% by mass or more, as a lower limit value. It is particularly preferably 20% by mass or more. The upper limit is preferably 60% by mass or less, more preferably 50% by mass or less, and particularly preferably 40% by mass or less.

The content of the radically polymerizable component (A) in the adhesive composition P is preferably 70% by mass or more, preferably 75% by mass or more, and further 80% by mass as the lower limit value. The above is preferable. Further, the upper limit value is preferably 99% by mass or less, preferably 97% by mass or less, and further preferably 95% by mass or less.

(1-2) Ion-polymerizable component (B)
The ion-polymerizable component (B) in the present embodiment is preferably a component that exhibits predetermined adhesiveness by ion-polymerizing with the ions generated by the ultraviolet-activated ion polymerization initiator (D). The ion-polymerizable component (B) may be a cationically polymerizable component or an anionically polymerizable component, but is preferably a cationically polymerizable component from the viewpoint of variety of material selection. As the ion-polymerizable component (B), one type may be used alone, or two or more types may be used in combination.

The cationically polymerizable component may be a monomer or a prepolymer. Examples of the cationically polymerizable component as a monomer include alkyl-substituted alkenes such as inden and kumaron, ethyl vinyl ethers, n-butyl vinyl ethers, cyclohexyl vinyl ethers, butanediol divinyl ethers, vinyl ethers such as diethylene glycol divinyl ethers, and bisphenol A diglycidyl ethers. , Bisphenol F diglycidyl ethers, ethylene glycol diglycidyl ethers, glycidyl ethers such as their hydrogenated additives, 3-ethyl-3-hydroxyethyloxetane, 1,4-bis [(3-ethyl-3-oxetanylmethoxy) Oxetans such as methyl] benzene, alicyclic epoxys such as 3,4-epoxycyclohexylmethyl (3,4-epoxy) cyclohexanecarboxylate, bis (3,4-epoxycyclohexyl) adipate, N-vinylcarbazole, etc. Can be mentioned. Among the above, glycidyl ethers or alicyclic epoxies are preferable from the viewpoint of more accurately performing the two-step polymerization reaction of radical polymerization and ionic polymerization.

Examples of the cationically polymerizable component that is a prepolymer include an epoxy resin, an oxetane resin, and a vinyl ether resin. Examples of the epoxy resin include compounds obtained by epoxidizing polyhydric phenols such as bisphenol resin and novolak resin with epichlorohydrin, and compounds obtained by oxidizing linear olefin compounds and cyclic olefin compounds with peroxides and the like. Can be mentioned.

Among the above, those having an epoxy group or a glycidyl ether group are preferable, and those having an alicyclic structure are particularly preferable. Specifically, the above-mentioned glycidyl ethers are preferable, in particular, bisphenol A diglycidyl ether and hydrogenated bisphenol A diglycidyl ether are preferable, and further, hydrogenated bisphenol A diglycidyl ether is preferable. A compound having an epoxy group or a glycidyl ether group is preferably used because it is cationically polymerized and exhibits a predetermined adhesiveness. Further, since the alicyclic structure is bulky and hydrophobic, the viscous adhesive obtained by using the cationically polymerizable component having the alicyclic structure becomes more excellent in blister resistance. Further, the diglycidyl ether having a bisphenol A skeleton has a similar chemical structure to the urethane acrylate-based oligomer obtained by using the above-mentioned dicyclohexylmethane diisocyanate, and therefore has good compatibility.

From the above, it is preferable that the radically polymerizable component (A) and the ionic polymerizable component (B) each contain an alicyclic structure.

The content of the ionic polymerizable component (B) in the adhesive composition P is preferably 0.1% by mass or more as a lower limit value from the viewpoint of making the step followability more excellent. It is preferably 0.5% by mass or more, and more preferably 1% by mass or more. On the other hand, as the upper limit value, from the viewpoint of further exerting the performance of the radically polymerizable component (A), it is preferably 40% by mass or less, more preferably 30% by mass or less, and further 20% by mass or less. It is preferable to have.

Further, the content of the ion-polymerizable component (B) is preferably 1 part by mass or more as a lower limit value with respect to 100 parts by mass of the radical-polymerizable component (A) from the viewpoint of step followability. It is preferably 4 parts by mass or more, and more preferably 4 parts by mass or more. On the other hand, as the upper limit value, from the viewpoint of further exerting the performance of the radically polymerizable component (A), it is preferably 100 parts by mass or less, preferably 50 parts by mass or less, and further 15 parts by mass or less. Is preferable.

(1-3) Visible light activated radical polymerization initiator (C)
The visible light-activated radical polymerization initiator (C) in the present embodiment may be any as long as it can be activated by irradiation with visible light to generate radicals and polymerize the above-mentioned radical polymerizable component (A). .. As the visible light-activated radical polymerization initiator (C), one type may be used alone, or two or more types may be used in combination.

Examples of the visible light-activated radical polymerization initiator (C) include acylphosphine oxide compounds; 4,4'-bis (diethylamino) benzophenone, and 4,4'-bis (N, N'-dimethylamino). Dialkylaminobenzophenone compounds such as benzophenone; metallocenes such as bis (η5-24-cyclopentadiene-l-yl) bis [2,6-difluoro-3- (lH-pyrrole-l-yl) phenyl] titanium; Examples thereof include camphorquinone, and among them, an acylphosphine oxide-based compound is preferable from the viewpoint of solubility in a coating liquid and color.

Examples of the acylphosphine oxide-based compound include 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, and 2,4,6-trimethyl. Benzoyl-diphenyl-phosphinate and the like are mentioned, and among them, 2,4,6-trimethylbenzoyl-diphenyl-phos from the viewpoint of solubility in the coating liquid and the color of the sheet (mainly yellowish). Finoxide is preferred.

The content of the visible light-activated radical polymerization initiator (C) in the adhesive composition P is 0.05 parts by mass or more as a lower limit with respect to 100 parts by mass of the radically polymerizable component (A). It is preferably 0.1 parts by mass or more, and further preferably 0.2 parts by mass or more. On the other hand, the upper limit value is preferably 5 parts by mass or less, preferably 3 parts by mass or less, and further preferably 1.5 parts by mass or less.

(1-4) Ultraviolet activated ion polymerization initiator (D)
The ultraviolet-activated ion polymerization initiator (D) in the present embodiment may be any as long as it can be activated by irradiation with ultraviolet rays to generate ions and polymerize the above-mentioned ion-polymerizable component (B). As the ultraviolet activated ion polymerization initiator (D), one type may be used alone, or two or more types may be used in combination.

Examples of the ultraviolet activated ion polymerization initiator (D) include onium such as aromatic sulfonium ion, aromatic oxosulfonium ion, and aromatic iodonium ion, and tetrafluoroborate, hexafluorophosphate, hexafluoroantimonate, and hexa. Examples thereof include compounds composed of anions such as fluoroarsenate. Specifically, iodonium, (4-methylphenyl) [4- (2-methylpropyl) phenyl] -hexafluorophosphate (1-), triarylsulfonium hexafluorophosphate, triarylsulfonium tetrakis- ( Pentafluorophenyl) borate, etc., among them, iodonium, (4-methylphenyl) [4- (2-methylpropyl) phenyl] -hexafluoro from the viewpoint of solubility in the coating liquid and handleability. Phenyl (1-) is preferred.

The content of the ultraviolet-activated ion polymerization initiator (D) in the adhesive composition P is 0.5 parts by mass or more as a lower limit value with respect to 100 parts by mass of the ion-polymerizable component (B). It is preferably 2 parts by mass or more, and more preferably 5 parts by mass or more. On the other hand, the upper limit value is preferably 50 parts by mass or less, preferably 40 parts by mass or less, and further preferably 30 parts by mass or less.

(1-5) Various Additives The adhesive composition P contains various additives such as a silane coupling agent, an ultraviolet absorber, an antistatic agent, a tackifier, an antioxidant, and a light stabilizer, if desired. , Softeners, fillers, refractive index adjusters and the like can be added. The polymerization solvent described later is not included in the additives constituting the adhesive composition P.

Here, when the adhesive composition P contains a silane coupling agent, the obtained adhesive has improved adhesion to a glass member or a plastic plate. As a result, the obtained viscous adhesive becomes more excellent in step followability and blister resistance under high temperature and high humidity conditions.

The silane coupling agent is preferably an organosilicon compound having at least one alkoxysilyl group in the molecule, which has good compatibility with each of the above-mentioned components and has light transmittance.

Examples of such a silane coupling agent include polymerizable unsaturated group-containing silicon compounds such as vinyltrimethoxysilane, vinyltriethoxysilane, and methacrypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, and 2-(. 3,4-Epoxycyclohexyl) Silicon compounds having an epoxy structure such as ethyltrimethoxysilane, mercapto group-containing silicon compounds such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, and 3-mercaptopropyldimethoxymethylsilane. , Amino group-containing silicon compounds such as 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-Chloropropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, or at least one of these and an alkyl group-containing silicon compound such as methyltriethoxysilane, ethyltriethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane Examples thereof include a condensate with. These may be used individually by 1 type, and may be used in combination of 2 or more type.

When the adhesive composition P contains a silane coupling agent, the content thereof is based on 100 parts by mass of the total of the radically polymerizable component (A) and the ionic polymerizable component (B) (polymerizable component). , 0.01 part by mass or more, particularly preferably 0.05 part by mass or more, and further preferably 0.1 part by mass or more. The content is preferably 1 part by mass or less, particularly preferably 0.5 part by mass or less, and further 0.3 parts by mass or less with respect to 100 parts by mass of the total of the polymerizable components. Is preferable.

(2) Production of Adhesive Composition The adhesive composition P contains a radically polymerizable component (A), an ionic polymerizable component (B), and a visible light-activated radical polymerization initiator (C). , UV-activated ion polymerization initiator (D) can be mixed, and if desired, an additive can be added to produce the product.

Here, when a (meth) acryloyl group-containing monomer or a vinyl group-containing monomer is used as the radically polymerizable component (A), they have a relatively small molecular weight and a low viscosity, so that each of them does not require a solvent. It is possible to mix the components. The adhesive composition P can be used as it is as a coating liquid as a solvent-free adhesive composition.

[Adhesive]
The adhesive according to the present embodiment is obtained by irradiating the adhesive composition P (usually the coating film of the adhesive composition P) with visible light to polymerize the radically polymerizable component (A). It is obtained by the above and is in a semi-cured state. Structurally, the adhesive according to the present embodiment is activated by a polymer derived from the radically polymerizable component (A), preferably an acrylic polymer, an ionic polymerizable component (B), and ultraviolet rays. Contains an ultraviolet activated ion polymerization initiator (D). The adhesive according to the present embodiment may contain a residue of the visible light-activated radical polymerization initiator (C) in addition to the above components.

In the residue of the visible light-activated radical polymerization initiator (C), the visible light-activated radical polymerization initiator (C) contained in the adhesive composition P remains without being cleaved by visible light irradiation. It was done. Therefore, the content thereof is not large, and is usually 0.0001% by mass or more and 0.1% by mass or less, preferably 0.0001% by mass or more and 0.01% by mass or less in the adhesive. Is.

Visible light irradiation can be preferably performed by irradiating light rays such as a high-pressure mercury lamp, a fusion H lamp, and a xenon lamp through an optical filter whose wavelength can be selected. In this case, the wavelength of the light beam is limited to 380 nm or more, preferably 390 nm or more by the wavelength selectable optical filter.

Examples of the wavelength selectable optical filter as described above include a short wavelength cut filter, a bandpass filter, a filter for mercury exposed light, and an optical substrate having an absorption wavelength of 390 nm or less, such as a triacetyl cellulose film and a polyethylene na. A phthalate film, a transparent resin film or the like having a surface treatment coating that absorbs an absorption wavelength of 390 nm or less can be used.

The irradiation amount of visible light ^{is preferably 5 mW / cm 2} or more, particularly preferably 15 mW / cm ² or more, and further preferably 30 mW / cm ² or more. The illuminance is preferably 300 mW / cm ² or less, particularly preferably 250 mW / cm ² or less, and further preferably 200 mW / cm ² or less. The amount of light is ^{preferably 200 mJ / cm 2} or more, particularly preferably 300 mJ / cm ² or more, and further preferably 500 mJ / cm ² or more. Further, the light amount is preferably at 5000 mJ / cm ² or less, particularly preferably at 4000 mJ / cm ² or less, and further preferably not 2000 mJ / cm ² or less.

The adhesive according to the present embodiment includes a radically polymerizable component (A), an ion-polymerizable component (B), a visible light-activated radical polymerization initiator (C), and an ultraviolet-activated ion polymerization initiator (ultraviolet-activated ion polymerization initiator). Since the adhesive composition P containing D) is irradiated with visible light, only the radically polymerizable component (A) is radically polymerized without polymerizing the ion-polymerizable component (B). It is possible, which results in a semi-cured state. In this way, the semi-cured adhesive is easy to follow the step even when it is attached to the display body component having the step, and it is suppressed that gaps, floats, etc. occur in the vicinity of the step. Excellent step followability.

The gel fraction of the adhesive adhesive according to the present embodiment is preferably 30% or more, particularly preferably 35% or more, and further preferably 40% or more. The gel fraction is preferably 70% or less, particularly preferably 66% or less, and further preferably 63% or less. When the gel fraction of the adhesive adhesive is in the above range, the initial step followability becomes more excellent. Here, the method for measuring the gel fraction of the adhesive is as shown in the test example described later.

[Adhesive sheet]
The adhesive sheet according to the present embodiment has an adhesive layer made of the adhesive as described above, and preferably adheres one display body component to another display body component. It has an adhesive layer for the purpose, and the adhesive layer is made of the above-mentioned adhesive.

FIG. 1 shows a specific configuration as an example of the adhesive sheet according to the present embodiment. As shown in FIG. 1, the adhesive adhesive sheet 1 according to the embodiment peels off the two release sheets 12a and 12b so as to be in contact with the release surfaces of the two release sheets 12a and 12b. It is composed of an adhesive layer 11 sandwiched between the sheets 12a and 12b. The peeling surface of the release sheet in the present specification means a surface of the release sheet that has peelability, and includes both a surface that has been peeled and a surface that exhibits peelability without peeling. ..

(1) Adhesive layer The adhesive layer 11 is composed of the above-mentioned adhesive, that is, the adhesive composition P is semi-cured by irradiation with visible light. It is composed.

The thickness of the adhesive layer 11 (value measured according to JIS K7130: 1999) in the adhesive sheet 1 according to the present embodiment is preferably 10 μm or more, more preferably 25 μm or more. In particular, it is preferably 50 μm or more, and more preferably 75 μm or more. The thickness is preferably 1000 μm or less, more preferably 400 μm or less, and particularly preferably 300 μm or less. The adhesive layer 11 may be formed as 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 becomes easy to exert a desired adhesive force. Further, when the thickness of the adhesive layer 11 is 1000 μm or less, the workability is good.

When the above-mentioned adhesive composition P is a solvent-free adhesive composition, a thick film (preferably a thickness of 100 μm or more) is not required because the solvent volatilization step after coating is not required. ), The adhesive layer 11 can be easily formed.

(2) Release sheet The release sheets 12a and 12b protect the adhesive layer 11 until the adhesive sheet 1 is used, and the adhesive sheet 1 (adhesive layer 11) is used. Sometimes peeled off. In the adhesive sheet 1 according to the present embodiment, one or both of the release sheets 12a and 12b are not always necessary.

Examples of the release sheets 12a and 12b include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polyethylene naphthalate film, and polybutylene. Telephthalate film, polyurethane film, ethylene vinyl acetate film, ionomer resin film, ethylene / (meth) acrylic acid copolymer film, ethylene / (meth) acrylic acid ester copolymer film, polystyrene film, polycarbonate film, polyimide film, fluorine A resin film or the like is used. In addition, these crosslinked films are also used. Further, these laminated films may be used.

It is preferable that the peeling surfaces (particularly the surfaces in contact with the adhesive layer 11) of the peeling sheets 12a and 12b are subjected to a peeling treatment. Examples of the release agent used in the release treatment include alkyd-based, silicone-based, fluorine-based, unsaturated polyester-based, polyolefin-based, and wax-based release agents. Of the release sheets 12a and 12b, it is preferable that one release sheet is a heavy release type release sheet having a large release force and the other release sheet is a light release type release sheet having a small release 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 characteristics (total light transmittance)
The total light transmittance of the adhesive layer 11 of the adhesive sheet 1 according to the present embodiment is preferably 90% or more, particularly preferably 95% or more, and further 98% or more. Is preferable. When the total light transmittance is 90% or more, the transparency is very high, which makes it suitable for optical applications. The total light transmittance in the present specification is a value measured according to JIS K7361-1: 1997.

(4) Production of Adhesive Adhesive Sheet As an example of production of the adhesive sheet 1, a coating layer is applied by applying the adhesive composition P to the release surface of one of the release sheets 12a (or 12b). After superimposing the peeling surface of the other release sheet 12b (or 12a) on the coating layer, the coating layer is irradiated with visible light (and heat treatment) to obtain the adhesive composition P. It is semi-cured to form the adhesive layer 11.

As another production example of the adhesive sheet 1, the adhesive composition P is applied to the peeled surface of one of the peeling sheets 12a (or 12b), and visible light irradiation (and heat treatment) is performed. After the adhesive composition P is semi-cured to form the adhesive layer 11, the release 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 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, a gravure coating method and the like can be used.

In the adhesive sheet 1 according to the present embodiment manufactured as described above, since the adhesive layer 11 is in a semi-cured state, it follows the step even when it is attached to a display body component having a step. It is easy to do and has excellent initial step followability.

[Display body]
As shown in FIG. 2, the display body 2 according to the present embodiment has a first display body constituent member 21 (one display body constituent member) having a step on at least the surface on the side to be bonded, and a second display body constituent member 21. A display body component 22 (another display body component) and an adhesive layer 11 located between them and adhering the first display body component 21 and the second display body component 22 to each other. Is configured with. In the display body 2 according to the present embodiment, the first display body component 21 has a step on the surface on the adhesive layer 11 side, and specifically, has a step due to the printing layer 3. ing.

The cured adhesive layer 11'in the display body 2 is obtained by irradiating the adhesive layer 11 of the adhesive sheet 1 described above with ultraviolet rays to polymerize the ion-polymerizable component (B). It is a thing and is in a cured state. Structurally, the cured adhesive layer 11'contains a polymer derived from the radically polymerizable component (A) and a polymer derived from the ionic polymerizable component (B). In the cured adhesive layer 11', it is presumed that the polymer derived from the ion-polymerizable component (B) is entwined with the polymer derived from the radical-polymerizable component (A). The cured adhesive layer 11'may contain a residue of the ultraviolet activated ion polymerization initiator (D), and further contains a residue of the visible light activated radical polymerization initiator (C). May be.

The residue of the ultraviolet-activated ion polymerization initiator (D) is the residue of the ultraviolet-activated ion polymerization initiator (D) contained in the adhesive layer 11 without being cleaved by ultraviolet irradiation. .. Therefore, the content thereof is not large, and is usually 0.0001% by mass or more and 0.1% by mass or less, preferably 0.0001% by mass or more and 0.01% by mass in the adhesive after curing. % Or less. The residue of the visible light-activated radical polymerization initiator (C) is equal to or less than the amount contained in the adhesive layer 11.

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 them.

The first display body constituent member 21 is preferably a protective panel made of a glass plate, a plastic plate, or the like, or a laminated body containing them. In this case, the print layer 3 is generally formed in a frame shape on the adhesive layer 11 side of the first display body constituent member 21.

The glass plate is not particularly limited, and for example, chemically strengthened glass, non-alkali glass, quartz glass, soda lime glass, barium / strontium-containing glass, aluminosilicate glass, lead glass, borosilicate glass, barium borosilicate. Examples include glass. The thickness of the glass plate is not particularly limited, but is usually 0.1 mm or more, preferably 0.2 mm or more. The thickness is usually 5 mm or less, preferably 2 mm or less.

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

Various functional layers (transparent conductive film, metal layer, silica layer, hard coat layer, antiglare layer, etc.) may be provided on one side or both sides of the glass plate or the plastic plate, or an optical member. May be laminated. Further, the transparent conductive film and the metal layer may be patterned.

The second display body component 22 is an optical member to be attached to the first display body component 21, a display module (for example, a liquid crystal (LCD) module, a light emitting diode (LED) module, an organic electroluminescence (organic)). An 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 shatterproof film, a polarizing plate (polarizing film), a polarizer, a retardation plate (phase difference film), a viewing angle compensation film, a brightness improving film, a contrast improving film, a liquid crystal polymer film, and a diffusion film. , Semi-transmissive reflective film, transparent conductive film and the like. Examples of the shatterproof film include a hard coat film in which a hard coat layer is formed on one side of the base film.

The material constituting the printing layer 3 is not particularly limited, and a known material for printing is used. The thickness of the print layer 3, that is, the lower limit of the height of the step is preferably 3 μm or more, more preferably 5 μm or more, particularly preferably 7 μm or more, and most preferably 10 μm or more. preferable. When the lower limit value is equal to or higher than the above value, it is possible to sufficiently secure concealment such as making the electrical wiring invisible to the viewer. The upper limit is preferably 60 μm or less, more preferably 50 μm or less, particularly preferably 40 μm or less, and even more preferably 20 μm or less. When the upper limit value is not more than the above, it is possible to prevent deterioration of the step followability of the adhesive layer 11'after curing with respect to the printing layer 3.

In order to manufacture the display body 2, as an example, one of the release sheets 12a of the adhesive sheet 1 is peeled off, and the exposed adhesive layer 11 of the adhesive sheet 1 is attached to the first display body. It is bonded to the surface of the component 21 on the side where the print layer 3 exists. At this time, since the adhesive layer 11 is excellent in the initial step followability, it is possible to prevent gaps and floats from being generated in the vicinity of the step due to the printing layer 3.

Next, the other release sheet 12b is peeled from the adhesive layer 11 of the adhesive sheet 1, and the exposed adhesive layer 11 of the adhesive sheet 1 and the second display body component 22 are separated from each other. Laminate to obtain a laminate. Further, as another example, the bonding order of the first display body constituent member 21 and the second display body constituent member 22 may be changed.

After that, the adhesive layer 11 in the laminated body is irradiated with ultraviolet rays. As a result, the ultraviolet activated ion polymerization initiator (D) is activated to generate ions, and the ions polymerize the ion-polymerizable component (B) in the adhesive layer 11. In this way, the adhesive layer 11 is cured and becomes the adhesive layer 11'after curing. The irradiation of the adhesive layer 11 with ultraviolet rays is usually performed through either the first display body component 21 or the second display body component 22, preferably the first display as a protective panel. This is done through the body component 21.

The irradiation of ultraviolet rays can be performed by a high-pressure mercury lamp, a fusion H lamp, a xenon lamp, or the like. The irradiation amount of ultraviolet rays ^{is preferably 20 mW / cm 2} or more, particularly preferably 50 mW / cm ² or more, and further preferably 100 mW / cm ² or more. The illuminance is preferably 500 mW / cm ² or less, particularly preferably 300 mW / cm ² or less, and further preferably 200 mW / cm ² or less. Amount is preferably at 500 mJ / cm ² or more, particularly preferably at 700 mJ / cm ² or more, and further preferably not 1000 mJ / cm ² or more. Further, the light amount is preferably at 10000 mJ / cm ² or less, particularly preferably at 8000 mJ / cm ² or less, and further preferably not 5000 mJ / cm ² or less.

The gel fraction of the post-curing adhesive that constitutes the post-curing adhesive layer 11'is preferably 60% or more, particularly preferably 65% or more, and further 67% or more. Is preferable. The gel fraction is preferably 99% or less, particularly preferably 85% or less, and further preferably 80% or less. The gel fraction of the adhesive after curing is higher than the gel fraction of the adhesive (before UV irradiation) described above, which indicates that the ion-polymerizable component (B) has polymerized. Can be recognized. When the gel fraction of the adhesive after curing is within the above range, the step followability and the blister resistance under high temperature and high humidity conditions become more excellent. Here, the method for measuring the gel fraction of the post-curing adhesive is as shown in a test example described later.

The haze value of the adhesive layer 11'after curing is preferably 2.0% or less, particularly preferably 1.5% or less, and further preferably 1.0% or less. .. When the haze value of the adhesive layer 11'after curing is 1.0% or less, the transparency is high and it is suitable for optical applications (for displays). The haze value in the present specification is a value measured according to JIS K7136: 2000.

In the above display body 2, since the adhesive layer 11'after curing exhibits high cohesive force and strong adhesiveness, it is excellent in step followability and blister resistance under high temperature and high humidity conditions. Therefore, even when the display body 2 is placed under high temperature and high humidity conditions (for example, 85 ° C., 85% RH, 72 hours), bubbles, floats, peeling, etc. are suppressed in the vicinity of the step. Further, even when the display body 2 is placed under high temperature and high humidity conditions (for example, 85 ° C., 85% RH, 72 hours) and outgas is generated from the display body constituent member made of a plastic plate or the like, adhesive adhesion after curing is performed. The generation of blister such as air bubbles, floating, and peeling at the interface between the agent layer 11'and the display body constituent members 21 and 22 is suppressed.

Here, the cured adhesive layer 11'in the display body 2 was formed using the adhesive composition P containing hydroxyalkyl (meth) acrylate as the radically polymerizable component (A). In this case, the display body 2 is subjected to high temperature and high humidity conditions, and then whitening is suppressed when the display body 2 is returned to room temperature, and the display body 2 is excellent in moisture and heat whitening resistance.

The excellent moisture-heat whitening resistance of the adhesive layer 11'after curing can be evaluated as follows. For example, two transparent conductive films on both sides of the adhesive layer 11 (a polyethylene terephthalate film provided with a transparent conductive film made of tin-doped indium oxide (ITO) on one side; the transparent conductive film is on the adhesive layer side. ), And the transparent conductive film is irradiated with ultraviolet rays from at least one side to obtain a laminate. The laminate is stored under the conditions of 85 ° C. and 85% RH (wet and heat conditions) for 120 hours, and then taken out at room temperature and normal humidity of 23 ° C. and 50% RH. The haze value (%) after the moist heat condition in the above laminate (measured according to JIS K7136: 2000; the same applies hereinafter) minus the haze value (%) before the moist heat condition (increase in the haze value after the moist heat condition). ) Is calculated.

The increase in haze value after moist heat conditions is preferably less than 0.50 points, and particularly preferably less than 0.20 points. In the above evaluation, it is preferable to use the non-alkali glass having a haze value of about 0%. The haze value of the adhesive layer after the above moist heat conditions is preferably 2.0% or less, particularly preferably 1.5% or less, and further preferably 1.0% or less. Is preferable.

The embodiments described above are described for facilitating the understanding of the present invention, and are not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

For example, either or both of the release sheets 12a and 12b in the adhesive sheet 1 may be omitted, and desired optical members may be laminated in place of the release sheets 12a and / or 12b. Further, the first display body constituent member 21 may have a step other than the print 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 adhesive layer 11 side.

Hereinafter, the present invention will be described in more detail with reference to Examples and the like, but the scope of the present invention is not limited to these Examples and the like.

[Example 1]
1. 1. Preparation of Urethane Acrylate Oligomer A urethane acrylate-based oligomer is obtained by polymerizing 1 mol of polypropylene glycol (PPG) having a weight average molecular weight of 9,200, 2 mol of isophorone diisocyanate (IPDI), and 2 mol of 2-hydroxyethyl acrylate (HEA). A polyether urethane acrylate having a weight average molecular weight of 9,900 was obtained.

The weight average molecular weights of polypropylene glycol and polyether urethane acrylate are standard polystyrene-equivalent values measured by gel permeation chromatography (GPC) according to the following conditions.
-GPC measuring device: HLC-8020 manufactured by Tosoh Corporation
-GPC column: Made by Tosoh (hereinafter listed in order of passage)
TSK guard volume HXL-H
TSK gel GMHXL (x2)
TSK gel G2000HXL
-Measurement solvent: tetrahydrofuran-Measurement temperature: 40 ° C

2. Preparation of Adhesive Composition (Meta) 40 parts by mass of 2-ethylhexyl acrylate, 20 parts by mass of isobornyl acrylate and 10 parts by mass of 2-hydroxyethyl acrylate as a (meth) acryloyl group-containing monomer were prepared in the above step 1. A radical polymerizable component (A) was obtained by mixing 30 parts by mass of a polyether urethane acrylate as a urethane acrylate-based oligomer and stirring the mixture.

100 parts by mass of the obtained radically polymerizable component (A), 30 parts by mass of hydrogenated bisphenol A diglycidyl ether as the ionic polymerizable component (B), and 2 as a visible light-activated radical polymerization initiator (C). , 4,6-trimethylbenzoyl-diphenyl-phosphine oxide 1 part by mass and iodonium as an ultraviolet activated ion polymerization initiator (D), (4-methylphenyl) [4- (2-methylpropyl) phenyl] 1 part by mass of a mixture of -hexafluorophosphate (1-) and propylene carbonate in a 3: 1 mass ratio, and 0.2 part by mass of 3-glycidoxypropyltrimethoxysilane as a silane coupling agent. Was mixed and stirred, and then statically defoamed to obtain a solvent-free adhesive composition.

3. 3. Manufacture of Adhesive Adhesive Sheet A heavy release type release sheet (manufactured by Lintec Corporation, product name "SP") in which one side of a polyethylene terephthalate film is peeled off with a silicone-based release agent from the solvent-free adhesive composition obtained in step 2 above. -PET752150 ") was applied to the peeled surface with a knife coater.

Next, the coating layer on the heavy-release type release sheet obtained above and the light-release type release sheet obtained by peeling one side of the polyethylene terephthalate film with a silicone-based release agent (manufactured by Lintec Corporation, product name "SP-PET382120"). And were bonded so that the peeled surface of the light peeling type peeling sheet was in contact with the coating layer.

Then, the coated layer was irradiated with visible light (wavelength 390 nm or more) under the following conditions via the heavy peeling type release sheet to selectively polymerize only the radically polymerizable component (A). As a result, an adhesive sheet having a structure of a heavy release type release sheet / an adhesive layer (thickness: 100 μm) / a light release type release sheet was obtained. The visible light was irradiated by irradiating a high-pressure mercury lamp through a triacetyl cellulose film (thickness 80 μm) that selectively transmits light having a wavelength of 390 nm or more.
<Visible light irradiation conditions>
-Light source: High-pressure mercury lamp-Optical filter: Triacetyl cellulose film with a thickness of 80 μm-Illuminance: 100 mW / cm ²
・ Integrated light intensity: 2000mJ / cm ²
・ UV illuminance / photometer uses "UVPF-A1" manufactured by iGraphics.

[Example 2]
An adhesive sheet was prepared in the same manner as in Example 1 except that the blending amount of the ionic polymerizable component (B) was changed to 5 parts by mass.

[Comparative Example 1]
An adhesive sheet was prepared in the same manner as in Example 1 except that the ion-polymerizable component (B) and the ultraviolet-activated ion polymerization initiator (D) were not blended.

[Comparative Example 2]
Except for the addition of 15 parts by mass of hydroxyl-terminated polybutadiene (manufactured by Nippon Soda Corporation, product name "GI-1000") at both ends instead of the ion-polymerizable component (B) and the ultraviolet-activated ion polymerization initiator (D). An adhesive sheet was produced in the same manner as in Example 1.

[Test Example 1] (Measurement of gel fraction)
The adhesive sheet obtained in Examples and Comparative Examples was cut into a size of 80 mm × 80 mm, the adhesive layer was wrapped in a polyester mesh (mesh size 200), and the mass was weighed with a precision balance. Then, the mass of the adhesive alone was calculated by subtracting the mass of the mesh alone. The mass at this time is M1.

Next, the adhesive adhesive wrapped in the polyester mesh was immersed in ethyl acetate at room temperature (23 ° C.) for 72 hours. Then, the adhesive was taken out, air-dried for 24 hours in an environment of a temperature of 23 ° C. and a relative humidity of 50%, and further dried in an oven at 80 ° C. for 12 hours. After drying, the mass was weighed with a precision balance, and the mass of the adhesive alone was calculated by subtracting the mass of the mesh alone. The mass at this time is M2. The gel fraction (%) is represented by (M2 / M1) × 100. As a result, the gel fraction of the adhesive was derived (after irradiation with visible light). The results are shown in Table 1.

On the other hand, the adhesive layer of the adhesive sheet obtained in Examples and Comparative Examples was irradiated with ultraviolet rays under the following conditions through the light release type release sheet to obtain the ion-polymerizable component (B). It was polymerized and the adhesive layer was cured to obtain an adhesive layer after curing. For the adhesive of the adhesive layer after curing, the gel fraction (after irradiation with ultraviolet rays) was derived in the same manner as described above. The results are shown in Table 1.

<Ultraviolet irradiation conditions>
・ Light source: High-pressure mercury lamp ・ Illuminance: 200 mW / cm ²
・ Integrated light intensity: 4000mJ / cm ²
・ UV illuminance / photometer uses "UVPF-A1" manufactured by iGraphics.

[Test Example 2] (Measurement of total light transmittance)
The light release type release sheet was peeled off from the adhesive sheet obtained in Examples and Comparative Examples, and the exposed adhesive layer was bonded to soda lime glass (manufactured by Nippon Sheet Glass Co., Ltd.) having a thickness of 1.1 mm. .. Next, under the same conditions as in Test Example 1, ultraviolet rays are irradiated through the heavy-release type release sheet to cure the adhesive layer to form a cured adhesive layer, and then the heavy-release type release sheet is peeled off. , This was used as a measurement sample. After performing background measurement with soda lime glass, the above measurement sample was measured using a haze meter (manufactured by Nippon Denshoku Kogyo Co., Ltd., product name "NDH-2000") in accordance with JIS K7361-1: 1997. The total light transmittance (%) was measured. The results are shown in Table 1.

[Test Example 3] (Evaluation of step followability)
On the surface of a glass plate (manufactured by NSG Precision Co., Ltd., product name "Corning Glass Eagle XG", length 90 mm x width 50 mm x thickness 0.5 mm), UV curable ink (manufactured by Teikoku Ink Co., Ltd., product name "POS-911 ink") ) Was screen-printed in a frame shape (outer shape: length 90 mm × width 50 mm, width 5 mm). Next, the printed ultraviolet curable ink is cured by irradiating with ultraviolet rays (80 W / cm ² , 2 metal halide lamps, lamp height 15 cm, belt speed 10 to 15 m / min), and a step (height of the step) due to printing is cured. A stepped glass plate having a size of 40 μm) was produced.

The light release type release sheet is peeled off from the adhesive sheet obtained in Examples and Comparative Examples, and the exposed adhesive layer is a polyethylene terephthalate film having an easy adhesive layer (manufactured by Toyobo Co., Ltd., product name "PET A4300"). , Thickness: 100 μm) and bonded to an easy-adhesion layer. Next, the heavy-release type release sheet is peeled off to expose the adhesive layer, and a laminator (manufactured by Fujipla, product name "LPD3214") is used so that the adhesive layer covers the entire surface of the frame-shaped print. Was laminated on the above-mentioned stepped glass plate. Then, it was autoclaved for 30 minutes under the conditions of 50 ° C. and 0.5 MPa, and left at normal pressure at 23 ° C. and 50% RH for 24 hours.

The adhesive layer of the obtained laminate was irradiated with ultraviolet rays through the polyethylene terephthalate film under the same conditions as in Test Example 1 to cure the adhesive layer, and after curing, the adhesive layer was cured. And said. Next, it was stored for 72 hours under high temperature and high humidity conditions of 85 ° C. and 85% RH (durability test), and then the adhesive layer (particularly near the step due to the printing layer) was visually confirmed, and the following criteria were used. The step followability was evaluated by. The results are shown in Table 2.
◯: There are no air bubbles (floating / peeling) near the step, and the adhesive adheres without gaps.
Δ: Bubbles are mixed in a part near the step.
X: Air bubbles are mixed in the entire circumference of the step.

[Test Example 4] (Evaluation of blister resistance)
A polyethylene terephthalate film (manufactured by Oike Kogyo Co., Ltd., ITO film) in which a transparent conductive film made of tin-doped indium oxide (ITO) is provided on one side of the adhesive layer of the adhesive sheet obtained in Examples and Comparative Examples. , Thickness: 125 μm), and a resin plate (manufactured by Mitsubishi Gas Chemicals, Inc., product name “Iupilon Sheet MR-58U”, thickness: 0.8 mm) having a polymethyl methacrylate layer and a polycarbonate layer. It was sandwiched between the surface on the polycarbonate layer side. Then, it was autoclaved for 30 minutes under the conditions of 50 ° C. and 0.5 MPa, and left at normal pressure at 23 ° C. and 50% RH for 24 hours.

The adhesive layer of the obtained laminate was irradiated with ultraviolet rays through the resin plate under the same conditions as in Test Example 1 to cure the adhesive layer, and after curing, the adhesive layer was formed. did. Then, it was stored for 72 hours under high temperature and high humidity conditions of 85 ° C. and 85% RH. Then, after curing, the state at the interface between the adhesive layer and the adherend was visually confirmed, and the blister resistance was evaluated according to the following criteria. The results are shown in Table 2.
◯: No air bubbles, floating or peeling were confirmed.
Δ: Bubbles are confirmed in some parts, but no floating or peeling is confirmed.
X: Bubbles or floating / peeling are confirmed on the entire surface.

[Test Example 5] (Evaluation of moisture heat bleaching resistance)
A polyethylene terephthalate film (manufactured by Oike Kogyo Co., Ltd., product name) in which a transparent conductive film made of tin-doped indium oxide (ITO) is provided on one side of the adhesive layer of the adhesive sheet obtained in Examples or Comparative Examples. "ITO film", thickness: 125 μm) was sandwiched between two sheets to obtain a laminated body. 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 under the conditions of 50 ° C. and 0.5 MPa, and then left at normal pressure at 23 ° C. and 50% RH for 24 hours. Then, using a haze meter (manufactured by Nippon Denshoku Kogyo Co., Ltd., product name "NDH2000"), the haze value (%) was measured according to JIS K7136: 2000.

Next, the adhesive layer of the laminated body was irradiated with ultraviolet rays through the film under the same conditions as in Test Example 1 to cure the adhesive layer, and after curing, the adhesive layer was formed. did. Next, this laminate was stored for 120 hours under moist heat conditions of 85 ° C. and 85% RH (durability test). Then, the temperature was returned to normal temperature and humidity at 23 ° C. and 50% RH, and the haze value (%) was measured again for the laminated body. The haze value was measured within 30 minutes after the laminate was returned to normal temperature and humidity.

The increase value (point) of the haze value (%) after the endurance test was calculated from the haze value (%) before the endurance test. The results are shown in Table 2.

As can be seen from Table 2, the adhesive sheet obtained in the examples was excellent in step followability and blister resistance, as well as in optical characteristics and moisture heat whitening resistance.

The adhesive composition, the adhesive and the adhesive sheet of the present invention can be suitably used for bonding, for example, a protective panel having a step and a desired display body constituent member.

1 ... Adhesive sheet 11 ... Adhesive layer 12a, 12b ... Peeling sheet 2 ... Display 11'... Cured adhesive layer 21 ... First display component 22 ... Second display Member 3 ... Print layer

Claims (11)

Radical polymerizable component (A) and
Ion-polymerizable component (B) and
Visible light-activated radical polymerization initiator (C) activated by visible light,
Contains an ultraviolet-activated ion polymerization initiator (D) that is activated by ultraviolet rays,
The radical polymerizable component (A) is viewed contains a (meth) acryloyl group-containing monomer having a hydroxy group in the urethane oligomers and molecules having a radical polymerizable group,
The content of the (meth) acryloyl group-containing monomer having a hydroxy group in the molecule in the radically polymerizable component (A) is 2% by mass or more and 30% by mass or less. Adhesive composition. The adhesive composition according to claim 1 , wherein the ion-polymerizable component (B) contains a compound having an epoxy group or a glycidyl ether group. The first or second claim, wherein the content of the ion-polymerizable component (B) is 1 part by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the radically polymerizable component (A). Adhesive composition. The adhesive composition according to any one of claims 1 to 3 , wherein the adhesive composition is a solvent-free adhesive composition. The adhesive composition according to any one of claims 1 to 4 is irradiated with visible light to polymerize the radically polymerizable component (A) to obtain an adhesive. A method for producing a viscous adhesive. A polymer derived from a radically polymerizable component (A) containing a urethane oligomer having a radically polymerizable group, and
Ion-polymerizable component (B) and
A viscous adhesive comprising an ultraviolet-activated ion polymerization initiator (D) that is activated by ultraviolet rays. An adhesive sheet having an adhesive layer made of the adhesive according to claim 6. The adhesive sheet includes two release sheets.
The adhesive sheet according to claim 7 , wherein the adhesive layer is sandwiched between the release sheets so as to be in contact with the release surfaces of the two release sheets. A method for manufacturing an adhesive sheet having an adhesive layer.
Apply the adhesive composition according to any one of claims 1 to 4, and then apply the adhesive composition.
A method for producing an adhesive sheet, which comprises polymerizing the radically polymerizable component (A) to form an adhesive layer by irradiating a coating film of the adhesive composition with visible light. .. One display body component and
With other display body components,
A method for manufacturing a display body including a cured adhesive layer for adhering the one display body component and the other display body component to each other.
By irradiating the layer of the adhesive composition containing the radical-polymerizable component (A) containing the radical-polymerizable group-containing urethane oligomer and the ionic-polymerizable component (B) with visible light, the above-mentioned The radically polymerizable component (A) is polymerized to form a polymer derived from the radically polymerizable component (A), thereby forming an adhesive layer.
The one display body component and the other display body component are bonded to each other via the adhesive layer.
Next, the adhesive layer is irradiated with ultraviolet rays to polymerize the ion-polymerizable component (B) to form a polymer derived from the ion-polymerizable component (B), and thus the post-curing viscosity. A method for manufacturing a display body, which comprises forming an adhesive layer. A laminate formed by laminating one display body component and another display body component via the adhesive layer of the adhesive sheet according to claim 7 or 8 is produced.
A method for producing a display body, which comprises irradiating the adhesive layer of the laminate with ultraviolet rays to polymerize the ion-polymerizable component (B) to form a cured adhesive layer.

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