TWI671375B - Photohardenable composition - Google Patents

Abstract

The present invention relates to a light-curing type adhesive composition, which can provide a laminate having the same adhesion strength as when oxygen is absent even in the case of light irradiation in the presence of oxygen. The light-curing of the present invention The type adhesive composition system contains (A) a 4-functional or more (meth) acrylate oligomer having a molecular weight of 10,000 to 70,000, (B) a monofunctional (meth) acrylate monomer, and (C) photoreaction Starter, (D) a tackifier with a softening point of 70 to 150 ° C, and (E) a liquid plasticizer.

Description

Photocuring type adhesive composition

The present invention relates to a photocurable adhesive composition, a laminate using the same, an optical display using the same, and a method for producing the laminate.

In recent years, image display devices used in smart phones and the like have been designed to directly reduce the visibility caused by surface reflections, such as liquid crystal display panels or organic EL panels, and touch panels. Lamination, or the bonding of the display body and the front panel, such as a protective panel, or the touch panel and the front panel for reinforcement. As a method of manufacturing an image display device, there is known a method of bonding, which is a method of applying a photocurable resin composition to a substrate on one side of a target, and then irradiating ultraviolet rays to form a photocurable resin composition. The resin layer temporarily hardens the resin layer, and is then bonded to the substrate on the other side (Patent Document 1).

However, the radical polymerization type of acrylic resins widely used in photocurable resin compositions has poor surface hardening properties due to oxygen in the air hindering hardening. Therefore, components that are not sufficiently hardened remain on the surface. As a result, there is a problem that the bonding strength is reduced. In response, Patent Document 2 discloses a method in which an inert gas such as nitrogen or the like is used under reduced pressure. The photocurable resin composition containing polyisoprene methacrylate oligomer, dicyclopentenyloxyethyl methacrylate, and lauryl methacrylate was irradiated with ultraviolet rays in the atmosphere.

[Prior technical literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2013-151151

[Patent Document 2] Japanese Patent Laid-Open No. 2013-254189

However, in the method described in Patent Document 2, it is necessary to introduce a device for setting a reduced pressure or an inert gas atmosphere in order to eliminate the influence of the hardening barrier caused by oxygen.

Therefore, in order to solve the above-mentioned problems, the present invention aims to provide a light-curing type adhesive composition, which is equivalent to the case where oxygen is absent even when light is irradiated in the presence of oxygen. Followed by a laminate of strength.

The present invention has the following configuration.

[1]. A light-curing type adhesive composition comprising: (A) a tetrafunctional or higher (meth) acrylic acid having a molecular weight of 10,000 to 70,000 Acrylate oligomer, (B) monofunctional (meth) acrylate monomer, (C) photoreaction initiator, (D) tackifier with softening point of 70 to 150 ° C, and (E) liquid Shape plasticizer.

[2]. The light-curing type adhesive composition according to the above [1], wherein the component (A) is selected from the group having (hydrogenated) polyisoprene, (hydrogenated) polybutadiene, and polyurethane in the skeleton. One or more groups of (meth) acrylate oligomers having an acid ester structure.

[3]. The light-curable adhesive composition according to the above [1] or [2], wherein the component (B) is selected from the group consisting of an alkyl (meth) acrylate and a hydroxy-substituted alkyl (meth) acrylate One or more of the group.

[4]. A laminate formed by laminating the light-curing type adhesive composition according to any one of the above [1] to [3].

[5]. The laminated body as described in [4] above, which is an optical display.

[6]. A manufacturing method, which is a method for manufacturing a laminated body, comprising the following steps (I) to (III): (I) combining the photohardening type of any one of the above [1] to [3] The material is suitable for the step of forming the photo-curable adhesive composition layer on the substrate 1; (II) irradiating the light-curable adhesive composition layer obtained in step (I) with energy rays to form a light-curable adhesive composition; And (III) a step of attaching the substrate 2 to the hardened product obtained in the step (II).

[7]. The manufacturing method according to the above [6], wherein the method is formed in step (II) The photo-curing type adhesive composition of the cured product has a reaction rate of 90% or more.

According to the present invention, it is possible to provide a light-curable adhesive composition that can provide a laminate having the same adhesive strength as when oxygen is absent, even when light is irradiated in the presence of oxygen.

[Best Mode for Implementing Invention]

(Light-curing type adhesive composition)

The photocuring type adhesive composition system contains (A) a tetrafunctional or higher (meth) acrylate oligomer having a molecular weight of 10,000 to 70,000, (B) a monofunctional (meth) acrylate monomer, and (C) light The reaction initiator, (D) a tackifier having a softening point of 70 to 150 ° C, and (E) a liquid plasticizer.

<(A) A tetrafunctional (meth) acrylate oligomer having a molecular weight of 10,000 to 70,000>

(A) A tetrafunctional or higher (meth) acrylate oligomer having a molecular weight of 10,000 to 70,000 (hereinafter also referred to as "(A) oligomer"), which has (meth) acrylic acid having 4 or more in the molecule base. In this specification, "(meth) acrylate" includes both "acrylate" and "methacrylate". In addition, "(meth) acrylfluorenyl" includes both "acrylfluorenyl" and "methacrylfluorenyl".

(A) The molecular weight of the oligomer is 10,000 to 70,000, and more preferably 20,000 to 50,000. When the molecular weight of the oligomer is less than 10,000, the elasticity tends to increase and the flexibility decreases. When the molecular weight of the oligomer exceeds 70,000, the viscosity increases and the workability tends to decrease. In this specification, the molecular weight is a weight average molecular weight measured by gel permeation chromatography (GPC) and converted using a standard polystyrene detection line.

(A) The functional number of the oligomer (the number of (meth) acrylfluorenyl groups) is 4 or more, preferably 4 to 10, more preferably 4 to 6, and particularly preferably 4. When the number of functional groups of the oligomer is 3 or less, when the light is irradiated in the presence of oxygen, the hardening barrier due to oxygen becomes significant, and then the strength decreases. Further, when the number of functional groups of the (A) oligomer is 10 or less, when light is irradiated in the presence of oxygen, an increase in elastic modulus accompanying an increase in the number of functional groups can be suppressed.

(A) The oligomer is not particularly limited, and examples thereof include a (meth) acrylate oligomer having (hydrogenated) polyisoprene, (hydrogenated) polybutadiene, or polyurethane in its backbone. These (meth) acrylate oligomers can be used singly or in combination of two or more kinds. Here, (hydrogenated) polyisoprene includes polyisoprene and / or hydrogenated polyisoprene, and (hydrogenated) polybutadiene includes polybutadiene and / or hydrogenated polybutadiene.

(Meth) acrylate oligomers having (hydrogenated) polybutadiene in the backbone, such as (hydrogenated) polybutadiene (meth) acrylate, and (hydrogenated) polybutadiene urethane (Meth) acrylate.

(Meth) acrylic acid with (hydrogenated) polyisoprene in the skeleton Examples of the ester oligomer include (hydrogenated) polyisoprene (meth) acrylate and (hydrogenated) polyisoprenecarbamate (meth) acrylate.

(Meth) acrylate oligomers having a polyurethane in the skeleton, such as polyether-based, polycarbonate-based, polyester-based, or combinations thereof Ester oligomers. As a commercially available product of the (A) (meth) acrylate oligomer having a polyurethane in the skeleton, for example, UV-7610B (manufactured by Nippon Synthetic Chemical Co., Ltd .; molecular weight 11,000, 9-functional) and the like can be mentioned.

(A) The oligomer is preferably a (hydrogenated) polybutadiene in a skeleton, and more preferably a urethane (meth) acrylic modified (hydrogenated) polybutadiene. (A) The oligomer may be one type, or two or more types may be used in combination.

<< (A) Manufacturing method of oligomer >>

(A) An oligomer can be manufactured by the method described in Unexamined-Japanese-Patent No. 2014-189758 or Unexamined-Japanese-Patent No. 2002-309185, for example. The (A) oligomer can be produced by a method of condensing a hydroxyl group-containing resin and (meth) acrylic acid, and a method of transesterifying a (meth) acrylate with a hydroxyl group-containing resin. . More specifically, (A) an oligomer can be produced by a method including "a step of obtaining a prepolymer having an isocyanate group" and "a step of obtaining a (meth) acrylate oligomer". The "step of obtaining a prepolymer having an isocyanate group" is a method in which a hydroxyl-containing (hydrogenated) polybutadiene and a hydroxyl-containing (hydrogenated) polyisoprene are selected from the group consisting of a hydroxyl-containing polyester, Hydroxy group-containing polyethers and hydroxyl group-containing polycarbonates in groups of 1 or more; and polyisocyanates Reacting to obtain a prepolymer having an isocyanate group; this "step of obtaining a (meth) acrylate oligomer" is a process in which a prepolymer having an isocyanate group and a (meth) acrylic acid containing a hydroxyl group Ester reaction, while (meth) acrylate oligomers. The "hydroxyl-containing resin", "polyisocyanate", "hydroxyl-containing (meth) acrylate," and "(meth) acrylate" are described below.

<<< Hydroxy-containing resin >>>

The hydroxyl-containing resin is a raw material resin of a (meth) acrylate oligomer. Examples of the resin include hydroxyl-containing (hydrogenated) polybutadiene, hydroxyl-containing (hydrogenated) polyisoprene, hydroxyl-containing polyester, Hydroxyl polyether and hydroxyl-containing polycarbonate. The hydroxyl group-containing resin is preferably (hydrogenated) polybutadiene having hydroxyl groups at both ends, (hydrogenated) polyisoprene having hydroxyl groups at both ends, polyester having hydroxyl groups at both ends, and polyesters at both ends. Polyether having a hydroxyl group, and polycarbonate having hydroxyl groups at both ends. This allows introduction of a (meth) acrylfluorenyl group having 1 or more at both ends, preferably a (meth) acrylfluorenyl group having 2 or more at both ends.

Examples of the (hydrogenated) polybutadiene having hydroxyl groups at both ends include GI-3000 (manufactured by Soda Corporation of Japan), GI-1000 (manufactured by Soda Corporation of Japan), G-3000 (manufactured by Soda Corporation of Japan), Poly bd ( (By Idemitsu Kosan Co., Ltd.). Examples of the (hydrogenated) polyisoprene having hydroxyl groups at both ends include Poly ip (manufactured by Idemitsu Kosan Co., Ltd.). Examples of polyesters having hydroxyl groups at both ends, polyethers having hydroxyl groups at both ends, and polycarbonates having hydroxyl groups at both ends include Polylite OD-X-2251 (manufactured by DIC Corporation), PPG (made by Mitsui Chemicals), Duranol T5652 (made by Asahi Kasei Chemicals), Preminol 4004, Preminol 4015 (made by Asahi Glass Co., Ltd.), Adeka polyether P-3000, Adeka new ace V14-90 (made by Adeka), etc. It is commercially available and can be used depending on the molecular weight or polarity for the purpose, and it is not particularly limited.

<<< Polyisocyanate >>>

The polyisocyanate is not particularly limited as long as it is a compound having two or more isocyanate groups, and examples thereof include aromatic, aliphatic, and alicyclic polyisocyanates.

Aromatic polyisocyanates include, for example, tolylene diisocyanate, diphenylmethane diisocyanate, polyphenylmethane polyisocyanate, modified diphenylmethane diisocyanate, xylylene diisocyanate, four Methylxylylene diisocyanate, phenylene diisocyanate, naphthalene diisocyanate, and the like.

Alicyclic polyisocyanate, for example, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, norbornene diisocyanate, 1,3-bis (isocyanatomethyl) ring Hexane, etc.

Examples of the aliphatic polyisocyanate include hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate, and lysine triisocyanate.

<<< Hydroxy (meth) acrylate >>>

The (meth) acrylate containing a hydroxyl group is not particularly limited as long as it is a (meth) acrylate compound having one or more hydroxyl groups and one or more (meth) acrylfluorenyl groups in the molecule. Hydroxyl-containing (meth) acrylates include, for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and (meth) acrylic acid 4-hydroxybutyl ester, 2- (meth) propenyloxyethyl-2-hydroxypropyl phthalate, caprolactone modified 2-hydroxyethyl (meth) acrylate, cyclohexyl (Meth) acrylic acid esters having one hydroxyl group and one (meth) acrylfluorenyl group in molecules such as alkanedimethanol mono (meth) acrylate; 2-hydroxy-3- (meth) acrylamide Molyloxypropyl (meth) acrylate, neopentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, etc. have one hydroxyl group and two or more (Meth) acrylfluorenyl (meth) acrylate and the like.

By adjusting the number of hydroxyl groups of the hydroxyl group-containing resin and the number of (meth) acrylfluorenyl groups in the hydroxyl group-containing (meth) acrylate, (A) an oligomer can be obtained. The combination of the hydroxyl-containing resin and the hydroxyl-containing (meth) acrylate is not particularly limited as long as the obtained oligomer has a (meth) acrylfluorenyl group having 4 or more in the molecule. Examples of the combination of a hydroxyl group-containing resin and a hydroxyl group-containing (meth) acrylate include the following combination of a hydroxyl group-containing resin and a hydroxyl group-containing (meth) acrylate. That is, the hydroxyl group-containing resin has For one hydroxyl resin, a (meth) acrylate containing a hydroxyl group is a (meth) acrylate compound having one hydroxyl group and one or more (meth) acrylfluorenyl groups.

<<< (meth) acrylate >>>

The (meth) acrylate is not particularly limited as long as it is a (meth) acrylate compound having one or more (meth) acrylfluorenyl groups in the molecule and not having a hydroxyl group. Examples of such a compound include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, octyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate. (Meth) acrylic acid alkyl esters such as esters, lauryl (meth) acrylate, cetyl (meth) acrylate, octadecyl (meth) acrylate, and isooctadecyl (meth) acrylate; Aryl (meth) acrylic acid such as benzyl methacrylate; cyclohexyl (meth) acrylate, isofluorenyl (meth) acrylate, dicyclopentenyl (meth) acrylate, etc. Alicyclic esters of (meth) acrylic acid; heterocyclic esters of (meth) acrylic acid, such as tetrahydrofurfuryl (meth) acrylate, and the like.

The conditions such as the amount of each component, the reaction temperature, and the reaction time are not particularly limited as long as the oligomer (A) can be obtained, and can be appropriately selected.

<(B) Monofunctional (meth) acrylate monomer>

(B) The monofunctional (meth) acrylate monomer is not particularly limited as long as it is a (meth) acrylate compound having one (meth) acrylfluorenyl group in the molecule. (B) Monofunctional (meth) acrylate monomers such as 2-ethylhexyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, (meth) Alkyl (meth) acrylic acid such as tert-butyl acrylate, isodecyl (meth) acrylate, lauryl (meth) acrylate, octadecyl (meth) acrylate, isooctadecyl (meth) acrylate Ester; methoxyethyl (meth) acrylate Alkoxy-substituted alkyl (meth) acrylates such as esters; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, ( Hydroxy-substituted alkyl (meth) acrylates such as 4-hydroxybutyl (meth) acrylate; 2- (meth) acrylfluorenyloxyethyl-2-hydroxypropyl phthalate, 2- Hydroxy-3- (meth) acrylfluorenyloxypropyl (meth) acrylate, caprolactone modified 2-hydroxyethyl (meth) acrylate, cyclohexanedimethanol mono (meth) acrylate Hydroxyl-substituted (meth) acrylates other than alkyl (meth) acrylates; hydroxyl-containing (meth) acrylates; benzyl (meth) acrylate, phenyl (meth) acrylate, etc .; dicyclopentenyloxyethyl ( (Meth) acrylate, norbornene (meth) acrylate, dicyclopentenyl (meth) acrylate, isofluorenyl (meth) acrylate, and the like. (B) The monofunctional (meth) acrylate monomer is preferably one or more selected from the group consisting of an alkyl (meth) acrylate and a hydroxy-substituted alkyl (meth) acrylate.

(B) A monofunctional (meth) acrylate monomer may be used 1 type, or 2 or more types may be used together. When two or more (B) monofunctional (meth) acrylate monomers are used in combination, a combination of an alkyl (meth) acrylate and a hydroxy-substituted alkyl (meth) acrylate is preferred.

(B) Monofunctional (meth) acrylate monomer is preferably 1 to 250 parts by mass, more preferably 20 to 200 parts by mass, and more preferably 30 to 100 parts by mass of (A) oligomer. 150 parts by mass, particularly preferably 40 to 90 parts by mass.

<(C) Photoreaction initiator>

(C) The photoreaction initiator is not particularly limited, and examples thereof include: 1- [4- (2-hydroxy Ethoxy) phenyl] -2-hydroxy-2-methyl-1-propane-1-one, 1-hydroxy-cyclohexyl-phenyl-one, benzophenone, 2,2-dimethoxy -1,2-diphenylethane-1-one, 2,4,6-trimethylbenzylidenediphenylphosphine oxide, 2,4,6-trimethylbenzylidenephenylethoxy Phosphine oxide, 2-benzyl-2-dimethylamino-1- (4-morpholinylphenyl) butanone-1, 2-hydroxy-2-methyl-1-phenyl-propane-1 -Ketone, 2-methyl-1- [4-methylthio] phenyl] -2-morpholinylpropane-1-one, benzoin methyl ether, benzoin ethyl ether, benzoin Butyl ether, benzoin isopropyl ether, bis (2,4,6-trimethylbenzyl) -phenylphosphine oxide, 2-hydroxy-2-methyl- [4- (1-methyl Vinyl) phenyl] propanol oligomer, 2-hydroxy-2-methyl- [4- (1-methylvinyl) phenyl] propanol oligomer, 2-hydroxy-2-methyl -1-phenyl-1-acetone, isopropylthioxanthone, methyl o-benzidine benzoate, [4- (methylphenylthio) phenyl] phenylmethane, 2,4-diethyl Thiothanone, 2-chlorothioxanthone, benzophenone, ethyl anthraquinone, benzophenone ammonium salt, thioxanthone ammonium salt, bis (2,6-dimethoxybenzyl) -2,4,4-trimethyl-pentylphosphine oxide, bis (2,6-dimethoxy Phenylbenzyl) -2,4,4-trimethyl-pentylphosphine oxide, 2,4,6-trimethylbenzophenone, 4-methylbenzophenone, 4,4'- Bisdiethylaminobenzophenone, 1,4benzophenylidenebenzene, 10-butyl-2-chloroacridone, 2,2'bis (o-chlorophenyl) 4,5,4 ', 5'-Di (3,4,5-trimethoxyphenyl) 1,2'-biimidazole, 2,2'bis (o-chlorophenyl) 4,5,4', 5'-tetra Phenyl-1,2'-biimidazole, 2-benzylidene naphthalene, 4-benzylidene biphenyl, 4-benzylidene diphenyl ether, acrylated benzophenone, bis (η 5 -2,4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H-pyrrole-1-yl) -phenyl) titanium, o-methylbenzylidenebenzene Formates, p-dimethylaminobenzoic acid ethyl ester, p-dimethylaminobenzoic acid isoamylethyl ester, active tertiary amines, carbazole · benzophenone-based photoreaction initiators, acridine-based Light reaction initiation Agents, triazine-based photoreactive initiators, benzamidine-based photoreactive initiators, and the like.

(C) The photoreaction initiator is selected from the group consisting of 1-hydroxy-cyclohexyl-phenyl-one and 2,4,6-trimethylbenzylphenylethoxyphosphine oxide. One or more kinds are preferable.

(C) The photoreaction initiator may be one type, or two or more types may be used in combination.

(C) The photoreaction initiator is preferably 0.1 to 20 parts by mass relative to 100 parts by mass of the oligomer (A), more preferably 0.5 to 15 parts by mass, and even more preferably 1 to 10 parts by mass.

<(D) Adhesive with softening point of 70 ~ 150 ℃>

The light-curing type adhesive composition system includes (D) an adhesion promoter having a softening point of 70 to 150 ° C (hereinafter also referred to as "(D) adhesion promoter"). The light-curing type adhesive composition contains (D) a tackifier, and then the strength is improved. At the same time, the hardened material can be softened and the followability to the adherend can be improved.

(D) The softening point of the tackifier is preferably 75 to 130 ° C, and more preferably 80 to 120 ° C from the viewpoints of adhesion strength and flexibility. The softening point is a value measured by the ring and ball method.

As long as it satisfies the above-mentioned softening point, the (D) tackifier is exemplified by rosin ester resins such as heterogeneous rosin esters, polymerized rosin esters, (hydrogenated) rosin esters; acrylic polymers, acrylic copolymers, etc. Acrylic resins; polysiloxane resins; terpene resins such as terpene resins, terpene phenol resins, modified terpene resins, and hydrogenated terpene resins; thermoplastic elastomers; petroleum resins; alicyclic saturated hydrocarbon groups Resin; rosin-based resins such as rosin phenol; xylene resins.

(D) A rosin ester resin is more preferable as a tackifier, and hydrogenated rosin ester is more preferable. The rosin ester resin is esterified with the carboxylic acid portion of the rosin, which can suppress the influence of the acid component on the adherend (for example, the wiring portion of the touch panel). In addition, hydrogenated rosin ester can prevent the coloring at the initial stage and when exposed to heat due to the hydrogenation of rosin. (D) One type of tackifier may be used, or two or more types may be used in combination.

(D) The amount of the tackifier may be 5 to 70% by mass based on 100% by mass of the photocurable adhesive composition. As long as it is within this range, the amount of the reaction component is appropriate so that good film properties can be obtained, and at the same time, the effect of exhibiting the adhesive strength is also advantageous. The tackifier is based on 100% by mass of the light-curing type adhesive composition, preferably 10 to 60% by mass, and more preferably 15 to 50% by mass.

<(E) Liquid plasticizer>

The photocuring type adhesive composition system contains (E) a liquid plasticizer. The so-called fluidity exhibited at 25 ° C under the atmospheric pressure of a liquid system can be, for example, a cone-and-plate viscometer to display a viscosity of 1,000 Pa · s or less (for example, 0.01 to 1,000 Pa‧ s viscosity). When the light-curing type adhesive composition contains (E) a liquid plasticizer, a cured product having a small elastic modulus and a softness can be obtained.

Examples of the (E) liquid plasticizer include dibutyl phthalate, diisononyl phthalate, diheptyl phthalate, bis (2-ethylhexyl) phthalate, Phthalate such as diisodecyl phthalate, butyl benzyl phthalate; dioctyl adipate, diisononyl adipate Alkyl esters of polycarboxylic acids such as esters, dioctyl sebacate, diisononyl sebacate, diisononyl 1,2-cyclohexanedicarboxylic acid (e.g., C3 to C12 alkanes of polycarboxylic acids) Esters, etc.); Phosphate esters such as tricresyl phosphate, tributyl phosphate; trimellitate; alkyl esters of polyoxyalkylene glycols such as triethylene glycol bis (2-ethylhexanoate) (For example, C3 to C12 alkyl esters of di-, tri-, or tetraethylene glycol, etc.); rubber-based polymers, rubber-based copolymers (for example, polyisoprene, polybutadiene, or polybutene, or The hydrides, derivatives with hydroxyl groups introduced into the two ends or derivatives with hydroxyl groups introduced into both ends of the hydrides, etc.); thermoplastic elastomers; petroleum resins; alicyclic saturated hydrocarbon-based resins; terpenes Terpene resins such as olefin resins, terpene phenol resins, modified terpene resins, and hydrogenated terpene resins; rosin resins such as rosin phenol; heterogeneous rosin ester resins, polymerized rosin ester resins, (hydrogenated) Rosin ester resins such as rosin ester resins; xylene resins; etc .; acrylic resins such as acrylic polymers and acrylic copolymers. These may be liquid.

As the liquid plasticizer (E), a rosin ester resin (but may be a liquid) is preferred, and a hydrogenated rosin ester (but may be a liquid) is more preferred. (E) The liquid plasticizer may be used alone or in combination of two or more.

From the viewpoint of exhibiting strength by the (D) tackifier, the (E) liquid plasticizer can be used in an amount of 300 parts by mass or less with respect to 100 parts by mass of the (D) tackifier. From the viewpoint of adhesion strength and flexibility, 10 to 250 parts by mass is preferable, 30 to 200 parts by mass is more preferable, and 50 to 150 parts by mass is more preferable.

<Further ingredients>

In the light-curing type adhesive composition, an adhesion-imparting agent, an antioxidant, an antifoaming agent, a pigment, a filler, a chain transfer agent, a light stabilizer, and a surface tension can be adjusted within a range that does not impair the effect of the present invention. Adjusting agent, leveling agent, ultraviolet absorber, foam suppressant, etc. Further components may be 1 type, or 2 or more types may be used together. The total content of the further components is preferably 0.01 to 15 parts by mass relative to 100 parts by mass of the (A) oligomer, more preferably 0.1 to 10 parts by mass, and even more preferably 1 to 5 parts by mass.

<Method for preparing light-curable adhesive composition>

The photocuring type adhesive composition system can be prepared by mixing the components. The method of mixing is not particularly limited, and various metals, plastic containers, stirring wings, and mixers can be used.

<Application of Photocurable Adhesive Composition>

The light-curable adhesive composition can be used for bonding any substrate 1 and any substrate 2. The substrate 1 and the substrate 2 may be the same substrate or different substrates. At least one of the substrate 1 and the substrate 2 may be a light-transmitting member. Accordingly, the light-curable adhesive composition is irradiated with energy rays (for example, ultraviolet rays) from the light-transmitting member side to form a cured resin layer. Examples of the light-transmitting member include glass, (meth) acrylic resin, polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polyimide, polyester, and cycloolefin polymer. Wait.

The light-curing type adhesive composition is more suitable for bonding display body and touch panel, display body and front panel, or touch panel and front panel. good. An optical display can be obtained by using a light-curing type adhesive composition and bonding a display and a touch panel, a display and a front panel, or a touch panel and a front panel.

Examples of the front panel include glass or engineering plastics, such as acrylic panels (either hard-coated or AR-coated on one or both sides), transparent plastic plates such as polycarbonate plates, PET plates, and PEN plates. . The front panel can also be used as a protective panel. Examples of the touch panel include a resistive film type, an electrostatic capacity type, an electromagnetic induction type, and an optical type touch panel. Examples of the display body include LCD, EL display, EL lighting, electronic paper, and plasma display. The front panel, the touch panel, and the display system may have a step, or may have a light shielding portion. Here, the light-shielding portion means a portion that does not irradiate the light-curing type adhesive composition applied on the adhesive surface with energy rays (for example, ultraviolet rays) required for curing.

(Laminate)

A laminated body obtained by laminating a light-curable adhesive composition is also an object of the present invention. Specifically, the laminated system is obtained by bonding arbitrary base materials 1 and arbitrary base materials 2 with a photocurable adhesive composition. The manufacturing method of a laminated body is not specifically limited, The manufacturing method of the laminated body mentioned later is preferable. In addition, it is preferable to use an optical display as the laminated body obtained by bonding with a photocurable adhesive composition.

(Manufacturing method of laminated body)

The manufacturing method of the laminated body is the base material 1 and the base material 2. A method for producing a laminated body formed by laminating a hardened product of a composition and a composition, and including the following steps (I) to (III): (I) applying a photocurable adhesive composition to the substrate 1 to form (Ii) a step of irradiating the light-curable adhesive composition layer obtained in step (I) with energy rays to form a light-curable adhesive composition hardened product; and (III) applying The step of bonding the base material 2 to the cured product obtained in the step (II).

In the method for manufacturing a laminated body, the photocurable adhesive composition, the base material 1 and the base material 2 include a preferable method, as described above. Therefore, the manufacturing method of the laminated body is preferably the manufacturing method of the optical display. Moreover, it is preferable that the laminated system obtained by the manufacturing method of a laminated body is an optical display body.

<Step (I)>

Step (I) is a step of applying a photocurable adhesive composition to the substrate 1 to form a photocurable adhesive composition layer.

The method of applying the photocurable adhesive composition to the substrate 1 is not particularly limited, and a method such as a die coater, a dispenser, and screen printing can be used. The thickness of the photocuring type adhesive composition layer is not particularly limited, and may be, for example, 10 to 500 μm, and more preferably 30 to 350 μm.

<Step (II)>

Step (II) is a photo-curing type adhesive composition layer obtained in step (I). A step of radiating energy rays to form a light-curing type cured composition.

The energy ray is not particularly limited, and active energy rays such as visible light rays, ultraviolet rays, X-rays, and electron rays can be used. The energy ray is preferably ultraviolet. As the ultraviolet light source, a light source emitting ultraviolet (UV) light can be used. Examples of the ultraviolet light source include metal halogen lamps, high-pressure mercury lamps, xenon lamps, mercury xenon lamps, halogen lamps, pulsed xenon lamps, and LEDs. The peak wavelength of the LED is not particularly limited, and examples thereof include 365 nm, 405 nm, 375 nm, 385 nm, and 395 nm. The light emitted from a light source other than the LED can be adjusted to light of a specific wavelength by passing through an optical filter. Specifically, adjustment can be performed by an optical filter that blocks light having a wavelength of 300 nm or less and / or an optical filter that blocks light having a wavelength of 500 nm or more.

The irradiation of the energy ray can be performed so that the accumulated light amount of the energy ray becomes 30 to 15,000 mJ / cm ² . The accumulated light amount is preferably 50 to 12,000 mJ / cm ² , and 100 to 10,000 mJ / cm ² is more preferable.

In step (II), energy rays are irradiated from the light-curing type to the composition side to form a cured resin layer. Here, when the substrate 1 is a light-transmitting member, the energy ray may irradiate the light-curable adhesive composition from the light-transmitting member side to form a cured resin layer.

The reaction rate of the photocurable adhesive composition in the hardened material formed in step (II) is not particularly limited, but it is preferably 90% or more. When the reaction rate is 90% or more, even if no further irradiation is performed after bonding, the steps can be simplified because they exhibit sufficient strength. In addition, there is no need to worry about the photo-curing type adhesive composition remaining because it is not cured. The permeation or damage of other components, and the exudation from hardened materials, can also be applied to the case where a light-shielding light-shielding layer is provided on the laminate, or the lamination of completely opaque substrates. The reaction rate is defined by the reduction rate of the (meth) acrylfluorenyl group in the photocurable adhesive composition before and after irradiation with energy rays (for example, ultraviolet rays), and can be measured by FT-IR. In the case where the (meth) acrylfluorenyl group in the photocuring type adhesive composition is completely reacted, it is set to 100%.

<Step (III)>

Step (III) is a step of laminating the base material 2 on the hardened material obtained in step (II) to obtain a laminate. The substrate 2 is placed on the substrate 1 on which the cured object is formed, and the substrate 1 and the substrate 2 can be bonded together. The substrate 2 is a substrate to which a photocurable adhesive composition is not applied in step (I).

The manufacturing method of a laminated body may include the process of pressurizing the bonded body which consists of the base material 1, the base material 2, and the hardened | cured material of the photocuring type adhesive composition among these. The manufacturing method of the laminated body is to improve the bonding strength of the laminated body by including pressure treatment. The pressure treatment can be performed using a rubber roller, a plate press, or the like.

[Example]

Hereinafter, the present invention will be described in more detail using examples and comparative examples. The invention is not limited by these examples. As long as there is no special description, it means mass parts and mass%.

Mix the ingredients shown in Table 1 evenly. A light-curing type adhesive composition of Example ‧ Comparative Example was prepared. Here, polybutadiene urethane acrylates A to F are produced according to the following Synthesis Examples 1 to 6.

Synthesis example 1 (manufacturing of polybutadiene urethane acrylate A)

A four-necked flask equipped with a thermometer, a stirrer, a dropping funnel, and a cooling tube with a drying tube was charged with hydroxyhydrogenated polybutadiene (GI-3000, manufactured by Japan Soda Co., Ltd., and number average molecular weight) at both ends. 3,000, iodine value 21, hydroxyl value 25-35 mgKOH / g) 300 g (molecular weight calculated by using hydroxyl value as 30 mg KOH: 0.080 mole), 0.1 g of p-methoxyphenol as polymerization inhibitor, and tin catalyst 2 0.1 g of dibutyltin dilaurate (L101, manufactured by Tokyo Fine Chemicals). After raising the temperature to 80 ° C., 30.2 g (0.136 mol) of isophorone diisocyanate (Desmodur I, manufactured by Sumika Bayer Urethane Co., Ltd.) was dropped uniformly over 1 hour. After completion of the dropwise addition, a reaction was performed at 80 ° C for 3 hours. Thereafter, 11.5 g (0.080 mol) of 4-hydroxybutyl acrylate (4-HBA, manufactured by Nippon Kasei Co., Ltd.) was added. After carrying out the reaction at 80 ° C for 4 hours, it was confirmed by FT-IR that the absorption at the isocyanate absorption wavelength (2270 nm) had disappeared and the reaction was completed. Thus, hydrogenated polybutadiene and isophorone diisocyanate were obtained as a repeating unit Polyurethane acrylate oligomer having an average number of functional groups of 2 having a polymerizable unsaturated bond at the terminal. The weight average molecular weight of the obtained hydrogenated polybutadiene skeleton polyurethane acrylate was 12,000. The weight average molecular weight is a value measured by GPC and converted using a standard polystyrene detection line.

Synthesis example 2 (manufacturing of polybutadiene urethane acrylate B)

A polyurethane having an average number of functional groups of 2 and a weight average molecular weight of 26,000 was obtained in the same manner as in Synthesis Example 1 except that the amount of isophorone diisocyanate was set to 26.7 g (0.120 mol). Acrylate oligomers.

Synthesis example 3 (manufacturing of polybutadiene urethane acrylate C)

A polyurethane having an average number of functional groups of 2 and a weight average molecular weight of 43,000 was obtained in the same manner as in Synthesis Example 1 except that the amount of isophorone diisocyanate was set to 23.1 g (0.104 mol). Acrylate oligomers.

Synthesis example 4 (manufacturing of polybutadiene urethane acrylate D)

The same procedure as in Synthesis Example 2 was carried out except that 2-hydroxy-3-propenyloxypropyl methacrylate (NK ester701A, manufactured by Shin Nakamura Chemical Co., Ltd.) was changed to 17.1 g (0.080 mol) in place of 4-hydroxybutyl acrylate. In the same manner, a polyurethane oligomer having an average number of functional groups of 4 and a weight average molecular weight of 24,000 can be obtained.

Synthesis example 5 (manufacturing of polybutadiene urethane acrylate E)

A polyurethane having an average number of functional groups of 4 and a weight average molecular weight of 36,000 was obtained in the same manner as in Synthesis Example 4 except that the amount of isophorone diisocyanate was set to 24.9 g (0.112 mol). Acrylate Oligomer.

Synthesis example 6 (manufacturing of polybutadiene urethane acrylate F)

A polyurethane having an average number of functional groups of 4 and a weight average molecular weight of 42,000 was obtained in the same manner as in Synthesis Example 4 except that the amount of isophorone diisocyanate was 23.1 g (0.104 mole). Acrylate oligomers.

Using the obtained photocurable adhesive composition of Example ‧ Comparative Example, the characteristics were measured in the following manner.

<Elasticity>

The elastic modulus was measured according to JIS Z1702 to produce a No. 3 dumbbell-shaped test piece (thickness: 1 mmt) using a tensile compression tester (manufactured by Minebea, Techno graph TG-2kN) at a speed of 10 mm / min. The dumbbell-shaped test piece was produced using a conveyor-type metal halide lamp (200 mW / cm ² manufactured by Eye Graphics Co., Ltd.) and a hardened product obtained by hardening a photocurable adhesive composition at 6,000 mJ / cm ² .

<OPEN intensity and CLOSE intensity>

Test pieces for measuring OPEN intensity and CLOSE intensity can be obtained as described below.

<< OPEN Hardening Test Pieces >>

The thickness of the coated part of the light-curable adhesive composition was 20 mm. On the substrate 1 (26 mm x 75 mm x 1.1 mmt, glass), three pieces of Saifan tape (50 μ mt) were used to adhere the 150 μ mt thickness. After forming a photocurable adhesive composition layer using a metal blade to coat the photocurable adhesive composition with a metal blade, a conveyor-type metal halide lamp (Eye Graphics, 200mW / cm ² ) was used at 3,000mJ / cm ² is irradiated with light from the light-curing type adhesive composition layer side to form a cured product of the light-curing type adhesive composition. The substrate 3 (26 mm × 150 mm × 0.1 mmt, PET) was placed on the cured product of the photocurable adhesive composition and joined to obtain an OPEN-cured strength measurement test piece.

<< CLOSE Hardened Strength Test Piece >>

The coated part of the light-curing type adhesive composition was 20 mm wide. On the substrate 1 (26 mm × 75 mm × 1.1 mmt, glass), three pieces of Saifan tape (50 μ mt) were used to stick the produced 150 μ mt. Thickness of the spacer, and coating the light-curable adhesive composition with a metal blade to form a light-curable adhesive composition layer, and then placing the substrate 2 (26 mm × 75 mm × 0.05 mmt, release PET) on the light-curable adhesive Next, on the composition layer and after bonding, it was irradiated with light through a substrate 1 at 3,000 mJ / cm ² by a conveyor-type metal halide lamp (200 mW / cm ² manufactured by Eye Graphics) to form a light-curing adhesive composition. Of hardened. The base material 2 was peeled, and the base material 3 (26 mm × 150 mm × 0.1 mmt, PET) was placed on the surface of the peeled base material 2 and bonded to obtain a CLOSE-hardened strength measurement test piece.

<< Determination of OPEN intensity and CLOSE intensity >>

The OPEN strength and CLOSE strength were measured at a speed of 300 mm / min using a tensile compression tester (manufactured by Minebea, Techno graph TG-2kN).

<Intensity change rate>

The intensity change rate of the above OPEN intensity and CLOSE intensity can be obtained. When the intensity change rate is 20% or less, it is evaluated as "○", and when it exceeds 20%, it is evaluated as "X".

<Response rate>

In the cured product of the photocurable adhesive composition, the reaction rate of the photocurable adhesive composition is the reduction rate of the acryl fluorenyl group before and after the energy rays of the photocurable adhesive composition are irradiated. By FT-IR (Perkin ELmer Company, Spectrum 100). The reduction rate is obtained by substituting the following formula (1) into the absorption peak height (X) of 800 to 820 cm ^-1 from the baseline in the FT-IR measurement pattern of the photocurable type composition layer before energy ray irradiation, It can be obtained from the absorption peak height (Y) of 800 to 820 cm ^-1 from the baseline in the FT-IR measurement pattern of the light-cured adhesive composition hardened product after irradiation with energy rays.

Response rate (%) = ((X-Y) / X) × 100‧‧‧ (1)

<< Determination of hardening rate of OPEN hardening >>

The coated part of the light-curing type adhesive composition was 20 mm wide. On the substrate 1 (26 mm × 75 mm × 1.1 mmt, glass), three pieces of Saifan tape (50 μ mt) were used to stick the produced 150 μ mt. Thickness of the spacer, and coating the light-curable adhesive composition with a metal blade to form a light-curable adhesive composition layer, and then a conveyor-type metal halide lamp (Eye Graphics, 200mW / cm ² ) was used at 3,000mJ / cm ^{2 The} light-curable adhesive composition is cured by irradiating light from the side of the photo-curable adhesive composition layer. The substrate 3 (26 mm × 150 mm × 0.1 mmt, PET) was placed on the cured product of the photocurable adhesive composition and joined to obtain an OPEN-cured strength measurement test piece. The cured product of the photocurable adhesive composition in the OPEN-cured strength measurement test piece was measured for the reaction rate of the photocurable adhesive composition.

<< Determination of the hardening rate of CLOSE hardening >>

The coated part of the light-curing type adhesive composition was 20 mm wide. On the substrate 1 (26 mm × 75 mm × 1.1 mmt, glass), three pieces of Saifan tape (50 μ mt) were used to stick the produced 150 μ mt. Thickness of the spacer, and coating the light-curable adhesive composition with a metal blade to form a light-curable adhesive composition layer, and then placing the substrate 2 (26 mm × 75 mm × 0.05 mmt, release PET) on the light-curable adhesive Next, on the composition layer and after bonding, it was irradiated with light through a substrate 1 at 3,000 mJ / cm ² by a conveyor-type metal halide lamp (200 mW / cm ² manufactured by Eye Graphics) to form a light-curing adhesive composition. Of hardened. The base material 2 was peeled, and the base material 3 (26 mm × 150 mm × 0.1 mmt, PET) was placed on the surface of the peeled base material 2 and bonded to obtain a CLOSE-hardened strength measurement test piece. The cured product of the photo-curable adhesive composition in the CLOSE-cured strength measurement test piece was measured for the reaction rate of the photo-curable adhesive composition.

The results are summarized in Table 1.

Examples 1 to 3 have a strength change rate of 0 (that is, there is no difference in strength between OPEN hardening and CLOSE hardening). That is, by including a (meth) acrylic acid ester oligomer having four or more functions, even in the case where light is irradiated in the presence of oxygen, the bonding strength is equivalent to that in the case where oxygen is not present. On the other hand, Comparative Examples 1 to 3 do not contain a (meth) acrylic acid ester oligomer having more than four functions. Compared with the adhesion strength when light is irradiated in the absence of oxygen, in the presence of oxygen When the light was irradiated, the bonding strength decreased.

[Industrial availability]

The photocurable adhesive composition is a laminate, and is particularly suitable as an adhesive for optical displays and optical displays.

Claims (7)

A light-curing type adhesive composition comprising: (A) a 4 to 6-functional (meth) acrylate oligomer having a molecular weight of 10,000 to 70,000, (B) a monofunctional (meth) acrylate monomer, (C) a photoreaction initiator, (D) a tackifier having a softening point of 70 to 150 ° C, and (E) a liquid plasticizer. The photocuring type adhesive composition according to claim 1, wherein the component (A) is selected from the group consisting of (hydrogenated) polyisoprene, (hydrogenated) polybutadiene, and polyurethane having One or more groups of meth) acrylate oligomers. The light-curable adhesive composition according to claim 1 or 2, wherein the component (B) is one or more members selected from the group consisting of an alkyl (meth) acrylate and a hydroxy-substituted alkyl (meth) acrylate. . A laminated body formed by laminating the light-curing type of any one of claims 1 to 3 with the composition. The laminated body as claimed in claim 4 is an optical display. A manufacturing method, which is a method for manufacturing a laminated body, comprising the following steps (I) to (III): (I) applying the photocurable adhesive composition of any one of claims 1 to 3 to the substrate 1, A step of forming a light-curable type adhesive composition layer; (II) a step of irradiating the light-curable type adhesive composition layer obtained in step (I) with energy rays to form a light-curable type adhesive composition hardened product; and ) A step of bonding the substrate 2 to the hardened product obtained in the step (II). The manufacturing method according to claim 6, wherein the reaction rate of the photocurable adhesive composition of the cured product formed in the step (II) is 90% or more.