JP2017061676A - Adhesive composition, laminate using the same and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive composition extremely excellent in adhesiveness for laminating a salient surface of a substrate sheet [I] having the salient surface and a flat surface of a substrate sheet [II] having the flat surface, and a laminate using the same and a manufacturing therefor.SOLUTION: There is provided an adhesive composition for laminating a salient surface of a substrate sheet [I] having the salient surface with surface roughness Ra of 0.1 to 100 μm and a flat surface of a substrate sheet [II] having the flat surface, and containing an urethane (meth)acrylate compound (A).SELECTED DRAWING: Figure 2

Description

  The present invention relates to an adhesive composition for bonding a convex surface of a base sheet [I] having a convex surface and a flat surface of a base sheet [II] having a flat surface, particularly, prism sheets to each other. The present invention relates to at least one of an adhesive composition for bonding together and an adhesive composition for bonding together a prism sheet and a diffusion sheet.

  Conventionally, ultraviolet curable adhesives, thermosetting adhesives, and the like have been used as adhesives for bonding prism sheets and the like. For example, Patent Document 1 describes “three bond 3042B” as a specific example of an ultraviolet curable adhesive, and “Sankei Epochure and Epochik Co., Ltd. 5: 1 as thermosetting adhesives”. "Mixed with".

JP 2007-155938 A

  However, in Patent Document 1, when a prism sheet is bonded, its adhesiveness is obtained to some extent, but it is still not satisfactory, and with the recent advancement of technology, further adhesiveness is required. ing.

  Therefore, in the present invention, under such a background, an adhesive for bonding the convex surface of the base sheet [I] having a convex surface and the flat surface of the base sheet [II] having a flat surface is provided. It is an object of the present invention to provide an adhesive composition having excellent properties, a laminate using the same, and a method for producing the same.

  However, as a result of intensive studies by the present inventors to solve the above problems, among photopolymerizable adhesives obtained by photopolymerizing a photocurable monomer, urethane (meth) acrylate is used as a photopolymerizable component. It has been found that by using a compound, it has an effect of better adhesion between the convex surface and the flat surface, and the present invention has been completed.

  That is, the first gist of the present invention is that the convex surface of the base sheet [I] having a convex surface with a surface roughness Ra of 0.1 to 100 μm and the flat surface of the base sheet [II] having a flat surface. It is an adhesive composition for bonding together, Comprising: It is related with the adhesive composition characterized by containing a urethane (meth) acrylate type compound (A).

  Furthermore, in this invention, let the 2nd summary be the laminated body on which base material sheet [I] and base material sheet [II] are laminated | stacked through the adhesive agent which consists of the said adhesive composition.

  And the manufacturing method of a laminated body provided with the process of laminating | stacking base material sheet [I] and base material sheet [II] using the said adhesive composition, and the process of hardening | curing the said adhesive composition is 1st. It is the gist of 3.

  The adhesive composition of the present invention comprises a convex surface of a base sheet [I] having a convex surface with a surface roughness Ra of 0.1 to 100 μm and a flat surface of a base sheet [II] having a flat surface. It is an adhesive composition for bonding, and contains a urethane (meth) acrylate compound (A), and therefore has very excellent adhesiveness.

  Further, the urethane (meth) acrylate compound (A) is a reaction product of a hydroxyl group-containing (meth) acrylate compound (a1), a polyvalent isocyanate compound (a2), and a polyol compound (a3) ( By being a (meth) acrylate type compound (A1), it will become further excellent in adhesiveness.

  Furthermore, by containing the photopolymerizable compound (B) other than the urethane (meth) acrylate-based compound (A), the viscosity can be lowered and the coating property becomes excellent.

  And when the said photopolymerizable compound (B) contains the photopolymerizable compound (B1) containing a proton-accepting group, adhesiveness with a base material sheet will become further excellent.

  Furthermore, when the content ratio of the urethane (meth) acrylate compound (A) and the photopolymerizable compound (B) is 1: 2 to 1: 3 by weight, the adhesiveness to the base sheet is further improved. become.

  Furthermore, when it contains (meth) acrylic resin (C), it will become excellent in coating property.

  Further, when it further contains a photopolymerization initiator (D), it can be cured by ultraviolet rays, and the workability is improved.

  Further, when the base sheet [I] and the base sheet [II] are laminated via an adhesive composed of the above adhesive composition, the laminate is more excellent in temporal stability without peeling off of the adhesive layer. The body comes to be obtained.

  If the base sheet [I] and the base sheet [II] are at least one of a prism sheet and a diffusion sheet, respectively, there are few contact points for bonding due to the apex angle on the prism sheet or the diffusion sheet. Therefore, it has been difficult to achieve sufficient adhesion in the past, but it can have very excellent adhesion.

  Using the adhesive composition, a method for producing a laminate comprising a step of laminating a base sheet [I] and a base sheet [II], and a step of curing the adhesive composition. A more highly reliable laminate can be obtained.

It is sectional drawing which is one suitable embodiment of the laminated body of this invention. It is a disassembled perspective view explaining the laminated body shown in FIG. In the exploded perspective view shown in FIG. 2, it is sectional drawing which cut | disconnected the prism sheet 2 and the prism sheet 3 along X-X '. 3 is a cross-sectional view similar to FIG. 3 except that the prism sheet 2 shown in the cross-sectional view of FIG. It is sectional drawing which showed bonding of the diffusion sheet 1 and the prism sheet 2 of the laminated body shown in FIG. 1 in detail. In the exploded perspective view shown in FIG. 2, it is sectional drawing which cut | disconnected the diffusion sheet 1 and the prism sheet 2 along X-X '(equivalent to the exploded view of FIG. 5).

  Next, embodiments of the present invention will be described in detail. However, the present invention is not limited to this embodiment.

  In the present invention, “(meth) acrylate” is a generic term for acrylate and methacrylate, and “(meth) acryl” is a generic term for acrylic and methacrylic. “Polyfunctional” means having two or more (meth) acryloyl groups in the molecule.

<Adhesive composition>
The adhesive composition of the present invention comprises a convex surface of a base sheet [I] having a convex surface with a surface roughness Ra of 0.1 to 100 μm and a flat surface of a base sheet [II] having a flat surface. It is the adhesive composition for bonding, Comprising: A urethane (meth) acrylate type compound (A) is contained. Here, the components of the adhesive composition will be described.

[Urethane (meth) acrylate compound (A)]
The urethane (meth) acrylate compound (A) is a compound having an ethylenically unsaturated group and a urethane bond, and in particular, a hydroxyl group-containing (meth) acrylate compound (a1) and a polyvalent isocyanate compound (a2). Reaction products and reaction products of a hydroxyl group-containing (meth) acrylate compound (a1), a polyvalent isocyanate compound (a2) and a polyol compound (a3) can be mentioned. Among them, urethane (meth) acrylate compounds which are reaction products of a hydroxyl group-containing (meth) acrylate compound (a1), a polyvalent isocyanate compound (a2) and a polyol compound (a3) are particularly preferable from the viewpoint of adhesiveness. (A1).

Examples of the hydroxyl group-containing (meth) acrylate compound (a1) include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 4-hydroxybutyl (meta). ) Acrylate, hydroxyalkyl (meth) acrylate such as 6-hydroxyhexyl (meth) acrylate, 2-hydroxyethyl acryloyl phosphate, 2- (meth) acryloyloxyethyl-2-hydroxypropyl phthalate, caprolactone-modified 2-hydroxyethyl ( (Meth) acrylate, dipropylene glycol (meth) acrylate, fatty acid-modified glycidyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono ( Data) acrylate, 2-hydroxy-3- (meth) acryloyloxy propyl (meth) hydroxyl group-containing (meth) acrylate compound containing one ethylenically unsaturated group such as acrylate;
Hydroxyl group-containing (meth) acrylate compounds containing two ethylenically unsaturated groups such as glycerin di (meth) acrylate and 2-hydroxy-3-acryloyl-oxypropyl methacrylate;
Pentaerythritol tri (meth) acrylate, caprolactone modified pentaerythritol tri (meth) acrylate, ethylene oxide modified pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, caprolactone modified dipentaerythritol penta (meth) acrylate, ethylene Examples thereof include hydroxyl group-containing (meth) acrylate compounds containing three or more ethylenically unsaturated groups such as oxide-modified dipentaerythritol penta (meth) acrylate.

Among these, a hydroxyl group (meth) acrylate compound having 1 to 3 ethylenically unsaturated groups is preferable from the viewpoint of ensuring the flexibility of the cured product and excellent curability, and having one ethylenically unsaturated group. Compounds include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, hydroxyalkyl (meth) acrylates such as 6-hydroxyhexyl (meth) acrylate, As a compound having two saturated groups, glycerin di (meth) acrylate, and as a compound having three ethylenically unsaturated groups, pentaerythritol tri (meth) acrylate is preferable in terms of excellent reactivity and versatility. Among these, compounds having one ethylenically unsaturated group are preferable from the viewpoint that the curing shrinkage of the cured product when cured can be reduced, and in particular, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meta) ) Acrylate is preferred.
These hydroxyl group-containing (meth) acrylate compounds (a1) can be used alone or in combination of two or more.

  Examples of the polyvalent isocyanate compound (a2) include aromatics such as tolylene diisocyanate, diphenylmethane diisocyanate, polyphenylmethane polyisocyanate, modified diphenylmethane diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, phenylene diisocyanate, and naphthalene diisocyanate. Aliphatic polyisocyanates such as polyisocyanates, pentamethylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate, lysine triisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, norbornene diisocyanate, 1 Examples include alicyclic polyisocyanates such as 3-bis (isocyanatomethyl) cyclohexane, trimer compounds or multimeric compounds of these polyisocyanates, allophanate polyisocyanates, burette polyisocyanates, water-dispersed polyisocyanates, and the like. .

Among these, diisocyanate compounds are preferable from the viewpoint of stability during the urethanization reaction, and in particular, aliphatic diisocyanates such as pentamethylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate, and hydrogenated diphenylmethane diisocyanate. , Cycloaliphatic diisocyanates such as hydrogenated xylylene diisocyanate, isophorone diisocyanate, norbornene diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane are preferably used, and more preferably isophorone diisocyanate, hydrogenated in view of low curing shrinkage. Diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, and norbornene diisocyanate are used and are particularly preferred. The hydrogenated diphenylmethane diisocyanate in view of excellent reactivity and versatility, hydrogenated xylylene diisocyanate, isophorone diisocyanate is used.
Moreover, a polyvalent isocyanate type compound (a2) can be used 1 type or in combination of 2 or more types.

  The polyol compound (a3) may be a compound containing two or more hydroxyl groups. For example, an aliphatic polyol, an alicyclic polyol, a polyether polyol, a polyester polyol, a polycarbonate polyol, and a polyolefin polyol. , Polybutadiene polyols, polyisoprene polyols, (meth) acrylic polyols, polysiloxane polyols, and the like.

  Examples of the aliphatic polyol include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, trimethylene glycol, dimethylolpropane, neopentyl glycol, 2,2-diethyl-1,3-propanediol, and 2-butyl- 2-ethyl-1,3-propanediol, 1,4-tetramethylenediol, 1,3-tetramethylenediol, 2-methyl-1,3-trimethylenediol, 1,5-pentamethylenediol, 1,6 -Hexamethylenediol, 3-methyl-1,5-pentamethylenediol, 2,4-diethyl-1,5-pentamethylenediol, pentaerythritol diacrylate, 1,9-nonanediol, 2-methyl-1,8 -Two hydroxyl groups such as octanediol Aliphatic alcohols containing, sugar alcohols such as xylitol or sorbitol, glycerol, trimethylolpropane, fatty alcohols, etc., containing three or more hydroxyl groups such as trimethylol ethane.

  Examples of the alicyclic polyol include cyclohexanediols such as 1,4-cyclohexanediol and cyclohexyldimethanol, hydrogenated bisphenols such as hydrogenated bisphenol A, and tricyclodecane dimethanol.

  Examples of the polyether polyol include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polybutylene glycol, polypentamethylene glycol, polyhexamethylene glycol and other alkylene structure-containing polyether polyols, and random polyalkylene glycols. Or a block copolymer is mentioned.

  Examples of the polyester-based polyol include three types of components: a polycondensation product of a polyhydric alcohol and a polycarboxylic acid, a ring-opening polymer of a cyclic ester (lactone), a polyhydric alcohol, a polycarboxylic acid, and a cyclic ester. Examples include reactants.

  Examples of the polyhydric alcohol include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, trimethylene glycol, 1,4-tetramethylene diol, 1,3-tetramethylene diol, 2-methyl-1,3-trimethyl. Methylene diol, 1,5-pentamethylene diol, neopentyl glycol, 1,6-hexamethylene diol, 3-methyl-1,5-pentamethylene diol, 2,4-diethyl-1,5-pentamethylene diol, glycerin , Trimethylolpropane, trimethylolethane, cyclohexanediols (such as 1,4-cyclohexanediol), bisphenols (such as bisphenol A), sugar alcohols (such as xylitol and sorbitol), and the like.

  Examples of the polyvalent carboxylic acid include aliphatic dicarboxylic acids such as malonic acid, maleic acid, fumaric acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, and dodecanedioic acid, 1,4 -Arocyclic dicarboxylic acids such as cyclohexanedicarboxylic acid, aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, 2,6-naphthalenedicarboxylic acid, paraphenylene dicarboxylic acid and trimellitic acid.

  Examples of the cyclic ester include propiolactone, β-methyl-δ-valerolactone, and ε-caprolactone.

  As said polycarbonate-type polyol, the reaction product of a polyhydric alcohol and phosgene, the ring-opening polymer of cyclic carbonate (alkylene carbonate etc.), etc. are mentioned, for example.

  Examples of the polyhydric alcohol include polyhydric alcohols exemplified in the description of the polyester-based polyol. Examples of the alkylene carbonate include ethylene carbonate, trimethylene carbonate, tetramethylene carbonate, and hexamethylene carbonate. It is done.

  The polycarbonate-based polyol may be a compound having a carbonate bond in the molecule and a terminal being a hydroxyl group, and may have an ester bond together with the carbonate bond.

  Examples of the polyolefin-based polyol include those having a homopolymer or copolymer such as ethylene, propylene, and butene as a saturated hydrocarbon skeleton, and having a hydroxyl group at the molecular end.

Examples of the polybutadiene-based polyol include those having a butadiene copolymer as a hydrocarbon skeleton and having a hydroxyl group at the molecular end.
The polybutadiene-based polyol may be a hydrogenated polybutadiene polyol in which all or part of the ethylenically unsaturated groups contained in the structure thereof are hydrogenated.

Examples of the polyisoprene-based polyol include those having a copolymer of isoprene as a hydrocarbon skeleton and a hydroxyl group at the molecular end.
The polyisoprene-based polyol may be a hydrogenated polyisoprene polyol in which all or part of the ethylenically unsaturated groups contained in the structure is hydrogenated.

  As said (meth) acrylic-type polyol, what has at least two hydroxyl groups in the molecule | numerator of the polymer or copolymer of (meth) acrylic acid ester is mentioned, As this (meth) acrylic acid ester, For example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, (meth) acrylic (Meth) acrylic acid alkyl esters such as 2-ethylhexyl acid, decyl (meth) acrylate, dodecyl (meth) acrylate, octadecyl (meth) acrylate, and the like.

  Examples of the polysiloxane-based polyol include dimethyl polysiloxane polyol and methylphenyl polysiloxane polyol.

  Among these, polyester-based polyols and polyether-based polyols are preferable, and polyether-based polyols are particularly preferable in terms of the flexibility of the cured product (adhesive) and the compatibility with the photopolymerizable compound (B). Tetramethylene glycol is most preferred.

  Moreover, a polyol type compound (a3) can be used 1 type or in combination of 2 or more types.

  In the present invention, the number average molecular weight of the polyol compound (a3) is preferably 200 to 3,000, particularly 250 to 2,000, and more preferably 300 to 1,000. If the number average molecular weight is too small, the crosslinking density tends to be too high and the adhesion to the substrate tends to be poor, and if too large, the crystallinity tends to be high and the viscosity tends to be high.

In addition, said number average molecular weight is a number average molecular weight by standard polystyrene molecular weight conversion, a column is put into a high performance liquid chromatography (Nippon Waters, "Waters 2695 (main body)" and "Waters 2414 (detector)"). : Shodex GPC KF-806L (exclusion limit molecular weight: 2 × 10 ⁷ , separation range: 100 to 2 × 10 ⁷ , theoretical plate number: 10,000 plates / piece, filler material: styrene-divinylbenzene copolymer, filler It is measured by using three series of particle diameters: 10 μm).

  In the present invention, the urethane (meth) acrylate compound (A) can be produced as follows. Although the following description is about the thing formed by making a hydroxyl-containing (meth) acrylate type compound (a1), a polyvalent isocyanate type compound (a2), and a polyol type compound (a3) react, according to this method By performing, the thing formed by making a hydroxyl-containing (meth) acrylate type compound (a1) and a polyvalent isocyanate type compound (a2) react can also be manufactured.

For example,
(1) A method in which the hydroxyl group-containing (meth) acrylate compound (a1), the polyvalent isocyanate compound (a2), and the polyol compound (a3) are charged into the reactor or separately and reacted.
(2) A method of reacting a hydroxyl group-containing (meth) acrylate compound (a1) with a reaction product obtained by reacting a polyol compound (a3) and a polyvalent isocyanate compound (a2) in advance,
(3) A method of reacting a polyol compound (a3) with a reaction product obtained by reacting a polyvalent isocyanate compound (a2) with a hydroxyl group-containing (meth) acrylate compound (a1) in advance. However, the method (2) is preferable from the viewpoints of reaction stability and reduction of by-products.

  For the reaction between the polyol compound (a3) and the polyvalent isocyanate compound (a2), known reaction means can be used. At that time, for example, the molar ratio of the isocyanate group in the polyvalent isocyanate compound (a2) to the hydroxyl group in the polyol compound (a3) is usually about 2n: (2n-2) (n is an integer of 2 or more). By doing this, it is possible to obtain a terminal isocyanate group-containing urethane (meth) acrylate compound having an isocyanate group remaining, and after obtaining the compound, an addition reaction with the hydroxyl group-containing (meth) acrylate compound (a1) is performed. It can be carried out.

  The addition reaction of the reaction product obtained by reacting the polyol compound (a3) and the polyvalent isocyanate compound (a2) in advance with the hydroxyl group-containing (meth) acrylate compound (a1) is also a known reaction. Means can be used.

  The reaction molar ratio between the reaction product and the hydroxyl group-containing (meth) acrylate compound (a1) is, for example, that the polyisocyanate compound (a2) has two isocyanate groups and the hydroxyl group-containing (meth) acrylate compound (a1). ) Has one hydroxyl group, the reaction product: hydroxyl group-containing (meth) acrylate compound (a1) is about 1: 2, and the polyisocyanate compound (a2) has three isocyanate groups. When the hydroxyl group-containing (meth) acrylate compound (a1) has one hydroxyl group, the reaction product: hydroxyl group-containing (meth) acrylate compound (a1) is about 1: 3.

  In the addition reaction between the reaction product and the hydroxyl group-containing (meth) acrylate compound (a1), the reaction is terminated when the residual isocyanate group content in the reaction system is 0.5% by weight or less. A (meth) acrylate compound (A) is obtained.

  In the reaction between the polyol compound (a3) and the polyvalent isocyanate compound (a2), and further in the reaction between the reaction product and the hydroxyl group-containing (meth) acrylate compound (a1), a catalyst is used for the purpose of promoting the reaction. The catalyst is preferably an organic metal compound such as dibutyltin dilaurate, trimethyltin hydroxide, tetra-n-butyltin, zinc octenoate, tin octenoate, cobalt naphthenate, stannous chloride. , Metal salts such as stannic chloride, triethylamine, benzyldiethylamine, 1,4-diazabicyclo [2,2,2] octane, 1,8-diazabicyclo [5,4,0] undecene, N, N, N ′, Amine catalysts such as N′-tetramethyl-1,3-butanediamine, N-ethylmorpholine, bismuth nitrate, bibromide In addition to trout, bismuth iodide, bismuth sulfide, etc., organic bismuth compounds such as dibutyl bismuth dilaurate and dioctyl bismuth dilaurate, bismuth 2-ethylhexanoate, bismuth naphthenate, bismuth isodecanoate, bismuth neodecanoate, lauryl Organic acid bismuth such as bismuth acid salt, bismuth maleate, bismuth stearate, bismuth oleate, bismuth linoleate, bismuth acetate, bismuth bisneodecanoate, bismuth disalicylate, bismuth digallate Examples include bismuth-based catalysts such as salts, zirconium-based catalysts such as inorganic zirconium, organic zirconium and zirconium alone, and a combination of two or more catalysts such as zinc 2-ethylhexanoate / zirconium tetraacetylacetonate. , Dibutyltin dilaurate, 1,8-diazabicyclo [5,4,0] undecene is preferred. In addition, only 1 type of these catalysts may be used independently, and 2 or more types may be used together.

  In the reaction between the polyol compound (a3) and the polyvalent isocyanate compound (a2), and further in the reaction between the reaction product and the hydroxyl group-containing (meth) acrylate compound (a1), it reacts with the isocyanate group. An organic solvent having no functional group, for example, esters such as ethyl acetate and butyl acetate, ketones such as methyl ethyl ketone and methyl isobutyl ketone, and aromatic solvents such as toluene and xylene can be used.

  Moreover, reaction temperature is 30-90 degreeC normally, Preferably it is 40-80 degreeC, and reaction time is 2 to 10 hours normally, Preferably it is 3 to 8 hours.

Thus, the urethane (meth) acrylate compound (A) is obtained.
The weight average molecular weight of the urethane (meth) acrylate compound (A) is preferably 1,000 to 60,000, particularly 1,500 to 50,000, more preferably 2,000 to 30,000. It is preferable. If the weight average molecular weight is too small, curing shrinkage of the cured product (adhesive) when cured tends to be large, and if too large, the viscosity tends to be high and handling tends to be difficult.

In addition, said weight average molecular weight is a weight average molecular weight by standard polystyrene molecular weight conversion, column: Shodex GPC KF-806L (exclusion) in a high performance liquid chromatography (Showa Denko Co., Ltd. make, "Shodex GPC system-11 type | mold"). Limit molecular weight: 2 × 10 ⁷ , separation range: 100 to 2 × 10 ⁷ , theoretical plate number: 10,000 plate / piece, filler material: styrene-divinylbenzene copolymer, filler particle size: 10 μm) Measured by using series.

The urethane (meth) acrylate compound (A) has a viscosity at 60 ° C. of preferably 500 to 100,000 mPa · s, particularly 800 to 50,000 mPa · s, It is preferable that it is 000-35,000 mPa * s. If the viscosity is too high, a large amount of diluent must be used, and workability tends to be reduced. If the viscosity is too low, adhesion tends to be reduced.
In addition, the measuring method of a viscosity is based on an E-type viscometer.

  The content ratio of the urethane (meth) acrylate compound (A) in the adhesive composition of the present invention is preferably 3 to 70% by weight, particularly 5 to 60% by weight, more preferably 10 to 50% by weight. % Is preferred. If the content ratio of the urethane (meth) acrylate compound (A) is too low, the viscosity tends to be too low and workability tends to be lowered, and if it is too high, the adhesive force tends to be lowered.

[Photopolymerizable compound (B)]
The adhesive composition of the present invention preferably contains a photopolymerizable compound (B) other than the urethane (meth) acrylate compound (A).

  The photopolymerizable compound (B) used in the present invention is used for coating properties, curability, adhesiveness, and the like. For example, an ethylenically unsaturated compound having one ethylenically unsaturated group ( Hereinafter, it may be described as “monofunctional monomer”) and an ethylenically unsaturated compound having two or more ethylenically unsaturated groups (hereinafter sometimes referred to as “polyfunctional monomer”). It is preferably at least one selected. Among these, a monofunctional monomer is preferable in terms of coatability.

  Examples of the monofunctional monomer include styrene, vinyl toluene, chlorostyrene, α-methyl styrene, methyl (meth) acrylate, ethyl (meth) acrylate, acrylonitrile, vinyl acetate, 2-hydroxyethyl (meth) acrylate, and 2-hydroxy. Propyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, phenoxyethyl (meth) acrylate, 2-phenoxy-2-hydroxypropyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, 3- Chloro-2-hydroxypropyl (meth) acrylate, glycerin mono (meth) acrylate, glycidyl (meth) acrylate, lauryl (meth) acrylate, cyclohexyl (meth) acrylate, isoborni (Meth) acrylate, tricyclodecanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, dicyclopentanyl (meth) acrylate, n-butyl (meth) acrylate, Hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, dodecyl (meth) acrylate, n-stearyl (meth) acrylate, Benzyl (meth) acrylate, cyclic trimethylolpropane formal (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, phenol ethylene oxide modified (n = 2) (meth) acrylate Nonylphenol propylene oxide modified (n = 2.5) (meth) acrylate, 2- (meth) acryloyloxyethyl acid phosphate, 2- (meth) acryloyloxy-2-hydroxypropyl phthalate, etc. ) Acrylate, furfuryl (meth) acrylate, carbitol (meth) acrylate, ethyl carbitol (meth) acrylate, (3-ethyloxetane-3-yl) methyl (meth) acrylate, benzyl (meth) acrylate, butoxyethyl (meth) ) Acrylate, allyl (meth) acrylate, acryloylmorpholine, dimethylacrylamide, 2-hydroxyethylacrylamide, N-methylol (meth) acrylamide, N-vinylpyrrolidone, 2-vinylpi Jin, polyoxyethylene secondary alkyl ether acrylate.

  In addition, a Michael adduct of acrylic acid or 2-acryloyloxyethyldicarboxylic acid monoester can also be used in combination. As the Michael adduct of acrylic acid, acrylic acid dimer, methacrylic acid dimer, acrylic acid trimer, methacrylic acid A trimer, an acrylic acid tetramer, a methacrylic acid tetramer, etc. are mentioned. The 2-acryloyloxyethyl dicarboxylic acid monoester is a carboxylic acid having a specific substituent, for example, 2-acryloyloxyethyl succinic acid monoester, 2-methacryloyloxyethyl succinic acid monoester, 2-acryloyloxy Examples thereof include ethyl phthalic acid monoester, 2-methacryloyloxyethyl phthalic acid monoester, 2-acryloyloxyethyl hexahydrophthalic acid monoester, 2-methacryloyloxyethyl hexahydrophthalic acid monoester, and the like. Furthermore, other oligoester acrylates can also be mentioned.

  In addition, examples of the polyfunctional monomer include a bifunctional monomer and a trifunctional or higher functional monomer.

  Examples of the bifunctional monomer include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, and propylene. Glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, butylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, ethylene oxide modified bisphenol A type di (meth) ) Acrylate, propylene oxide modified bisphenol A type di (meth) acrylate, cyclohexanedimethanol di (meth) acrylate, Xylated cyclohexanedimethanol di (meth) acrylate, dimethylol dicyclopentane di (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, glycerin di (meth) Acrylate, pentaerythritol di (meth) acrylate, ethylene glycol diglycidyl ether di (meth) acrylate, diethylene glycol diglycidyl ether di (meth) acrylate, phthalic acid diglycidyl ester di (meth) acrylate, hydroxypivalic acid modified neopentyl glycol di (Meth) acrylate, isocyanuric acid ethylene oxide modified diacrylate and the like.

Examples of the tri- or higher functional monomer include trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, and dipentaerythritol hexa (meth). ) Acrylate, tri (meth) acryloyloxyethoxytrimethylolpropane, glycerin polyglycidyl ether poly (meth) acrylate, isocyanuric acid ethylene oxide modified tri (meth) acrylate, caprolactone modified dipentaerythritol penta (meth) acrylate, caprolactone modified dipenta Erythritol hexa (meth) acrylate, caprolactone-modified pentaerythritol tri (meth) acrylate, cap Lactone modified pentaerythritol tetra (meth) acrylate, ethylene oxide modified dipentaerythritol penta (meth) acrylate, ethylene oxide modified dipentaerythritol hexa (meth) acrylate, ethylene oxide modified pentaerythritol tri (meth) acrylate, ethylene oxide modified pentaerythritol Examples include tetra (meth) acrylate and ethoxylated glycerin triacrylate.
The photopolymerizable compound (B) may be used alone or in combination of two or more.

  In the present invention, the photopolymerizable compound (B) preferably contains a photopolymerizable compound (B1) containing a proton-accepting group in terms of adhesive strength. Furthermore, the photopolymerizable compound (B1) containing a proton-accepting group is preferably a photopolymerizable compound containing a nitrogen atom in terms of compatibility, and in particular, a photopolymerizable compound containing an amide group. It is preferable that it is a compound represented by the following general formula (1).

[Chemical formula 1]
^{_{CH 2 = C (R 1)}} -CONR 2 (R 3) ··· (1)
(In Formula (1), R ¹ represents a hydrogen atom or a methyl group, and R ² represents a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms which may have a substituent. , R ³ represents a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms, or R ² and R ³ may be bonded to each other and contain an oxygen atom. A member ring may be formed, provided that R ² and R ³ are not hydrogen atoms at the same time.)

  Examples of the compound represented by the general formula (1) include N-methyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, and N-isopropyl (meth). Acrylamide, N-butyl (meth) acrylamide, N-hexyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methylol-N-propane (meth) acrylamide, aminomethyl (meth) acrylamide, aminoethyl (meth) Examples include acrylamide, mercaptomethyl (meth) acrylamide, mercaptoethyl (meth) acrylamide, N-acryloylmorpholine, N-acryloylpiperidine, N-methacryloylpiperidine, N-acryloylpyrrolidine and the like. Acrylamide, dialkyl acrylamide such as diethyl acrylamide, cyclic amino acrylates such as N- acryloyl morpholine. Most preferred is dimethylacrylamide.

  In the present invention, the content (weight ratio) of the photopolymerizable compound (B1) containing a proton-accepting group in the photopolymerizable compound (B) is preferably 20 to 100% by weight, particularly 25 to 25%. It is preferably 98% by weight, more preferably 30 to 95% by weight. If the content ratio of the photopolymerizable compound (B1) containing such a proton-accepting group is too low, the adhesive strength between the base sheets tends to be low.

  Moreover, the content rate (weight ratio) of a urethane (meth) acrylate type compound (A) and a photopolymerizable compound (B) is 1: 1.5-1: 10 from the point of adhesiveness with a base material sheet. It is preferably 1,2 to 1: 8, particularly preferably 1: 2 to 1: 6, particularly preferably 1: 2 to 1: 3. When the content of the photopolymerizable compound (B) is too small, the viscosity tends to be high and the workability tends to be lowered. When the content is too large, the viscosity is too low and the workability is lowered and the optical properties are lowered. There is a tendency to end up.

[(Meth) acrylic resin (C)]
The adhesive composition of the present invention preferably further contains a (meth) acrylic resin (hereinafter sometimes simply referred to as “acrylic resin”) (C) from the viewpoint of film-forming properties at the time of coating. .

  The acrylic resin (C) in the present invention is obtained by polymerizing a monomer component containing a (meth) acrylic monomer, and the (meth) acrylic monomer is used alone or in combination of two or more. And polymerized.

  The acrylic resin (C) preferably contains a (meth) acrylic acid ester monomer (c1) as a polymerization component, and if necessary, a functional group-containing monomer (c2) and other copolymerizable monomers ( c3) can also be used as a copolymerization component.

  Examples of the (meth) acrylic acid ester monomer (c1) include, for example, aliphatic (meth) acrylic acid ester monomers such as (meth) acrylic acid alkyl ester, and aromatic monomers such as (meth) acrylic acid phenyl ester. Examples include (meth) acrylic acid ester monomers.

  Examples of such aliphatic (meth) acrylic acid ester monomers include alkyl (meth) acrylates in which the alkyl group usually has 1 to 20, particularly preferably 1 to 15, and more preferably 1 to 10 carbon atoms. Examples thereof include esters and (meth) acrylic acid esters having an alicyclic structure.

  As such (meth) acrylic acid alkyl ester, specifically, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, iso-butyl (meth) acrylate, tert-butyl ( (Meth) acrylate, n-propyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isodecyl (meth) acrylate, lauryl (meth) acrylate, cetyl ( Examples include meth) acrylate and stearyl (meth) acrylate.

  Specific examples of the (meth) acrylic acid ester having an alicyclic structure include cyclohexyl (meth) acrylate and isobornyl (meth) acrylate.

  Examples of aromatic (meth) acrylic acid ester monomers include phenyl (meth) acrylate, benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, phenyldiethylene glycol (meth) acrylate, and 2-hydroxy-3-phenoxypropyl. (Meth) acrylate, phenoxypolyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, nonylphenol ethylene oxide adduct (meth) acrylate, and the like.

  Examples of other (meth) acrylic acid ester monomers include tetrahydrofurfuryl (meth) acrylate. These may be used alone or in combination of two or more.

Among such (meth) acrylic acid ester monomers (c1), aliphatic (meth) acrylic acid ester monomers are excellent in terms of copolymerizability, coating film strength, ease of handling, and availability of raw materials. Monomers, typically methyl (meth) acrylate, n-butyl (meth) acrylate, and isobornyl (meth) acrylate are preferably used, and methyl (meth) acrylate is particularly preferable.
These (meth) acrylic acid ester monomers (c1) can be used alone or in combination of two or more.

  Examples of the functional group-containing monomer (c2) include a hydroxyl group-containing monomer, a carboxyl group-containing monomer, an alkoxy group-containing monomer, a phenoxy group-containing monomer, an amide group-containing monomer, an amino group-containing monomer, a nitrogen-containing monomer (however, the amide group described above) -Containing monomers and amino group-containing monomers), glycidyl group-containing monomers, phosphate group-containing monomers, sulfonic acid group-containing monomers, and the like. These may be used alone or in combination of two or more.

  Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 5-hydroxypentyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl ( (Meth) acrylate, 10-hydroxydecyl (meth) acrylate, (4-hydroxymethylcyclohexyl) methyl (meth) acrylate and other (meth) acrylic acid hydroxyalkyl esters, caprolactone-modified 2-hydroxyethyl (meth) acrylate, etc. Monomers containing primary hydroxyl groups such as caprolactone-modified monomers, 2-acryloyloxyethyl-2-hydroxyethylphthalic acid, N-methylol (meth) acrylamide, N-hydroxyethyl (meth) acrylamide, etc. -2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate, 2-hydroxy- Secondary hydroxyl group-containing monomers such as 3-phenoxypropyl (meth) acrylate; tertiary hydroxyl group-containing monomers such as 2,2-dimethyl-2-hydroxyethyl (meth) acrylate.

  In addition, polyethylene glycol esters of (meth) acrylic acid such as diethylene glycol mono (meth) acrylate and polyethylene glycol mono (meth) acrylate, polypropylene glycol esters of (meth) acrylic acid such as polypropylene glycol mono (meth) acrylate, polyethylene glycol- Oxyalkylene-modified monomers such as polypropylene glycol-mono (meth) acrylate, poly (ethylene glycol-tetramethylene glycol) mono (meth) acrylate, poly (propylene glycol-tetramethylene glycol) mono (meth) acrylate may be used.

  Examples of the carboxyl group-containing monomer include Michael addition of acrylic acid, methacrylic acid, crotonic acid, maleic acid, maleic anhydride, itaconic acid, fumaric acid, acrylamide N-glycolic acid, cinnamic acid, and (meth) acrylic acid. (Eg, acrylic acid dimer, methacrylic acid dimer, acrylic acid trimer, methacrylic acid trimer, acrylic acid tetramer, methacrylic acid tetramer, etc.), 2- (meth) acryloyloxyethyl dicarboxylic acid monoester (eg, 2-acryloyloxyethyl) Succinic acid monoester, 2-methacryloyloxyethyl succinic acid monoester, 2-acryloyloxyethyl phthalic acid monoester, 2-methacryloyloxyethyl phthalic acid monoester, 2-acryloyloxyethyl hexahi Rofutaru acid monoester, 2-methacryloyloxyethyl hexahydrophthalic acid mono ester) and the like. Such a carboxyl group-containing monomer may be used as it is, or may be used in the form of a salt neutralized with an alkali.

  Examples of the alkoxy group-containing monomer include 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, 2-butoxyethyl (meth) acrylate, and 2-butoxydiethylene glycol. (Meth) acrylate, methoxydiethylene glycol (meth) acrylate, methoxytriethylene glycol (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, methoxydipropylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, octoxypolyethylene glycol- Polypropylene glycol-mono (meth) acrylate, lauroxypolyethylene glycol mono (meth) acrylate, steer Alkoxy polyethylene glycol mono (meth) acrylate aliphatic of (meth) acrylic acid ester.

  Examples of the phenoxy group-containing monomer include phenoxyethyl (meth) acrylate, phenoxydiethylene glycol (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, and the like.

  Examples of the amide group-containing monomer include acrylamide, methacrylamide, N- (n-butoxyalkyl) acrylamide, N- (n-butoxyalkyl) methacrylamide, N, N-dimethyl (meth) acrylamide, N, N- Examples include diethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, acrylamide-3-methylbutylmethylamine, dimethylaminoalkylacrylamide, and dimethylaminoalkylmethacrylamide.

  Examples of the amino group-containing monomer include dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, and a quaternized product thereof.

  Examples of the nitrogen-containing monomer include acryloylmorpholine.

  Examples of the glycidyl group-containing monomer include glycidyl (meth) acrylate and allyl glycidyl ether.

  Examples of the phosphoric acid group-containing monomer include 2- (meth) acryloyloxyethyl acid phosphate (for example, “light ester P-1M”, “light acrylate P-1A” manufactured by Kyoeisha Chemical Co., Ltd.), bis (2 -(Meth) acryloyloxyethyl) acid phosphate, phosphate ester of polyethylene glycol monomethacrylate (for example, “Sipomer PAM100”, “Sipomer PAM4000”, etc. manufactured by Rhodia Nikka Co., Ltd.), phosphate ester of polyethylene glycol monoacrylate (for example, , "SipomerPAM5000" manufactured by Rhodia Nikka Co., Ltd.), phosphate ester of polypropylene glycol monomethacrylate (for example, "Sipomer PAM200" manufactured by Rhodia Nikka Co., Ltd.), polyp Polyalkylene glycol mono (meth) acrylate phosphate ester such as phosphate ester of pyrene glycol monoacrylate (for example, “Sipomer PAM300” manufactured by Rhodia Nikka Co., Ltd.), methylene phosphate (meth) acrylate, trimethylene phosphate ( Examples thereof include alkylene (meth) acrylates such as (meth) acrylate, propylene phosphate (meth) acrylate, and tetramethylene (meth) acrylate phosphate.

Examples of the sulfonic acid group-containing monomer include olefin sulfonic acids such as ethylene sulfonic acid, allyl sulfonic acid, and methallyl sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, styrene sulfonic acid, and salts thereof. .
These functional group-containing monomers (c2) can be used alone or in combination of two or more.

  Examples of the other copolymerizable monomer (c3) include acrylonitrile, methacrylonitrile, styrene, α-methylstyrene, vinyl acetate, vinyl propionate, vinyl stearate, vinyl chloride, vinylidene chloride, alkyl vinyl ether, vinyl toluene, Examples include vinyl pyridine, vinyl pyrrolidone, itaconic acid dialkyl ester, fumaric acid dialkyl ester, allyl alcohol, acrylic chloride, methyl vinyl ketone, N-acrylamidomethyltrimethylammonium chloride, allyltrimethylammonium chloride, and dimethylallyl vinylketone.

For the purpose of increasing the molecular weight, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate A compound having two or more ethylenically unsaturated groups such as divinylbenzene can also be used in combination.
These other copolymerizable monomers (c3) can be used alone or in combination of two or more.

  In the acrylic resin (C), the content ratio of the (meth) acrylic acid ester monomer (c1), the functional group-containing monomer (c2), and the other copolymerizable monomer (c3) is (meth) acrylic acid ester monomer (C1) is preferably 10 to 100% by weight, particularly preferably 20 to 95% by weight, and the functional group-containing monomer (c2) is preferably 0 to 90% by weight, particularly preferably 5 to 80% by weight, and other copolymerizable properties. The monomer (c3) is preferably 0 to 50% by weight, particularly preferably 0 to 40% by weight.

  The acrylic resin (C) in the present invention is preferably a polymer having a polymerization component of (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms in terms of excellent coating film strength, In particular, a polymer having methyl (meth) acrylate as a polymerization component is preferable, a polymer having methyl metallate as a polymerization component is preferable, and polymethyl methacrylate is particularly preferable.

  In the polymerization of the acrylic resin (C), for example, a conventionally known polymerization method such as solution radical polymerization, suspension polymerization, bulk polymerization, emulsion polymerization or the like can be employed. What is necessary is just to superpose | polymerize according to superposition | polymerization conditions.

  For example, in an organic solvent, a polymerization monomer such as the above (meth) acrylic acid ester monomer (c1), functional group-containing monomer (c2), other copolymerizable monomer (c3), polymerization initiator (azobisisobutyrate) Nitrile, azobisisovaleronitrile, 2,2-azobis-2,4-dimethylvaleronitrile, benzoyl peroxide, etc.) are mixed or added dropwise and refluxed or at 50 to 90 ° C. for 2 to 20 hours. What is necessary is just to perform radical polymerization.

The glass transition temperature (Tg) of the acrylic resin (C) is usually 0 to 180 ° C, preferably 15 to 175 ° C, particularly preferably 50 to 130 ° C. If the glass transition temperature is too high, the effect of alleviating the thermal shrinkage of the cured product tends to decrease, and if it is too low, the thermal durability of the cured product tends to decrease.
The measurement of the glass transition temperature is a value measured using a DSC (differential scanning calorimeter).

  The weight average molecular weight of the acrylic resin (C) thus obtained is usually 10,000 to 500,000, preferably 10,000 to 100,000. If the weight average molecular weight is too large, the coating strength tends to decrease, and if it is too small, the adhesion to a substrate such as a glass substrate or the coating appearance tends to decrease.

  The degree of dispersion (weight average molecular weight / number average molecular weight) of the acrylic resin (C) is usually 1 to 4, preferably 1.5 to 2.5.

In addition, said weight average molecular weight and number average molecular weight are based on standard polystyrene molecular weight conversion, a column is added to a high performance liquid chromatography (Nippon Waters Co., Ltd., "Waters2695 (main body)" and "Waters2414 (detector)"). : ShodexGPCKF-806L (exclusion limit molecular weight: 2 × 10 ⁷ , separation range: 100 to 2 × 10 ⁷ , theoretical plate number: 10,000 plates / piece, filler material: styrene-divinylbenzene copolymer, filler particle size : 10 μm), and the degree of dispersion is determined from the weight average molecular weight and the number average molecular weight.

  In the present invention, the use of a solvent-free acrylic resin (C1) that does not substantially contain a solvent as the acrylic resin (C) can be used for environmental measures such as VOC (volatile organic compound) regulations and a drying process. This is preferable in terms of improvement in production efficiency by being omissible, improvement in coating property on a material weak against heat and solvent, and the like.

  As the solventless acrylic resin (C1), an acrylic resin that does not substantially contain a solvent in the resin can be used. As the “acrylic resin substantially free of solvent”, the content of the solvent in the resin is usually 3% by weight or less, preferably 1% by weight or less, particularly preferably 0.5% by weight or less, and more preferably 0%. An acrylic resin that is 2% by weight or less may be mentioned.

  Such a solventless acrylic resin (C1) is generally prepared by a method in which a polymerizable monomer is polymerized at a high temperature without using a diluting solvent, or after a polymerizable monomer is polymerized using a diluting solvent. It is manufactured by a method that volatilizes and removes.

Specific examples of the solventless acrylic resin (C1) include, for example, “ARUFON UP-1000” (weight average molecular weight: 3000, glass transition temperature: −77 ° C.) manufactured by Toagosei Co., Ltd., and “ARUFONUP-1010”. (Weight average molecular weight: 1700, glass transition temperature: −31 ° C.), “ARUFONUP-1020” (weight average molecular weight: 2000, glass transition temperature: −80 ° C.), “ARUFONUP-1061” (weight average molecular weight: 1600, Glass transition temperature: −60 ° C.), “ARUFONUP-1080” (weight average molecular weight: 6000, glass transition temperature: −61 ° C.), “ARUFONUP-1110” (weight average molecular weight: 2500, glass transition temperature: −64 ° C.) "ARUFONUP-1150" (weight average molecular weight: 5000, glass transition temperature: 68 ° C.), “ARUFONUP-1170” (weight average molecular weight: 8000, glass transition temperature: −57 ° C.), “ARUFONUP-1190” (weight average molecular weight: 1700, glass transition temperature: −50 ° C.), “ARUFONUP-1500 (Dainal BR-50) (weight average molecular weight: 65000, glass transition temperature: 100 ° C.), “Dainal BR-60” (weight average molecular weight: 70000) manufactured by Mitsubishi Rayon Co., Ltd. (Glass transition temperature: 75 ° C.), “Dianal BR-80” (weight average molecular weight: 95000, glass transition temperature: 105 ° C.), “Dianal BR-82” (weight average molecular weight: 150,000, glass transition temperature: 95 ° C.) ), “Dianar BR-83” (weight average molecular weight: 40000, glass transition temperature) 105 ° C.), "Dianal BR-90" (weight average molecular weight: 230000, glass transition temperature: 65 ° C.) solvent-free non-functional group type such as an acrylic resin;
“ARUFON UH-2000” (weight average molecular weight: 11000, glass transition temperature: −55 ° C.), “ARUFONUH-2041” (weight average molecular weight: 2500, glass transition temperature: −50 ° C.), “ARUFONUH” manufactured by Toagosei Co., Ltd. -2170 "(weight average molecular weight: 14000, glass transition temperature: 60 ° C)," ARUFONUH-2190 "(weight average molecular weight: 6000, glass transition temperature: -47 ° C)," ARUFONUHE-2012 "(weight average molecular weight: 5800 Hydroxyl-containing type solvent-free acrylic resin such as glass transition temperature: 20 ° C.)
“ARUFON UC-3510” manufactured by Toagosei Co., Ltd. (weight average molecular weight: 2000, glass transition temperature: −50 ° C.), “Dianar BR-605” manufactured by Mitsubishi Rayon Co., Ltd. (weight average molecular weight: 50000, glass transition temperature: 60 ° C) carboxyl group-containing type solvent-free acrylic resin;
“ARUFON UG-4000” (weight average molecular weight: 3000, glass transition temperature: −61 ° C.), “ARUFONUG-4010” (weight average molecular weight: 2900, glass transition temperature: −57 ° C.), “ARUFONUG” manufactured by Toagosei Co., Ltd. -4035 "(weight average molecular weight: 11000, glass transition temperature: 52 ° C)," ARUFONUG-4040 "(weight average molecular weight: 11000, glass transition temperature: 63 ° C)," ARUFONUG-4070 "(weight average molecular weight: 9700, Epoxy group-containing type solvent-free acrylic resin such as glass transition temperature: 58 ° C);
“ARUFON US-6100” (weight average molecular weight: 2500, glass transition temperature: −58 ° C.), “ARUFONUS-6110” (weight average molecular weight: 2500, glass transition temperature: −57 ° C.), “ARUFONUS” manufactured by Toagosei Co., Ltd. An alkoxysilyl group-containing type solvent-free acrylic resin such as “-6150” (weight average molecular weight: 7000, glass transition temperature: −50 ° C.), “ARUFONUS-6170” (weight average molecular weight: 3000);
Etc.

  The glass transition temperature (Tg) of the solventless acrylic resin (C1) is usually −100 to 150 ° C., preferably −90 to 130 ° C., particularly preferably −90 to 120 ° C. If the glass transition temperature is too high, the effect of alleviating the thermal shrinkage of the cured product tends to decrease, and if it is too low, the thermal durability of the cured product tends to decrease or the coating strength tends to decrease.

  The weight average molecular weight of the solventless acrylic resin (C1) is usually 500 to 300,000, preferably 800 to 200,000, particularly preferably 1,000 to 150,000. If the weight average molecular weight is too large, the coating strength tends to decrease, and if it is too small, the adhesion to a substrate such as a glass substrate or the coating appearance tends to decrease.

  Moreover, as an acrylic resin (C), an organic solvent can be mix | blended and solvent containing acrylic resin (C2) can also be used from industrial merit, such as preparation being easy. Examples of the organic solvent include alcohols such as methanol, ethanol, propanol, n-butanol and i-butanol, ketones such as acetone, methyl isobutyl ketone, methyl ethyl ketone and cyclohexanone, cellosolves such as ethyl cellosolve, toluene and xylene. And the like, glycol ethers such as propylene glycol monomethyl ether, acetates such as methyl acetate, ethyl acetate and butyl acetate, and diacetone alcohol. These organic solvents may be used alone or in combination of two or more.

[Photopolymerization initiator (D)]
In the adhesive composition of the present invention, it is preferable to further contain a photopolymerization initiator (D) in that it can be cured by irradiation with active energy rays such as ultraviolet rays for a very short time.

  Examples of the photopolymerization initiator (D) include diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyldimethyl ketal, 4- (2-hydroxyethoxy) phenyl- (2 -Hydroxy-2-propyl) ketone, 1-hydroxycyclohexyl phenylketone, 2-methyl-2-morpholino (4-thiomethylphenyl) propan-1-one, 2-benzyl-2-dimethylamino-1- (4- Acetophenones such as morpholinophenyl) butanone and 2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl] propanone oligomer; benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl Benzo such as ether Benzophenone, methyl o-benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4′-methyl-diphenyl sulfide, 3,3 ′, 4,4′-tetra (t-butylperoxycarbonyl) benzophenone, 2,4,6-trimethylbenzophenone, 4-benzoyl-N, N-dimethyl-N- [2- (1-oxo-2-propenyloxy) ethyl] benzenemethananium bromide, (4-benzoylbenzyl) trimethylammonium Benzophenones such as chloride; 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, 1-chloro-4-propoxythioxanthone, 2- (3-dimethylamino-2-hydroxy ) -3, -Thioxanthones such as dimethyl-9H-thioxanthone-9-one mesochloride; 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl-pentyl Acylphosphine oxides such as phosphine oxide and bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide; In addition, as for these photoinitiators (D), only 1 type may be used independently and 2 or more types may be used together.

  Further, as these auxiliaries, triethanolamine, triisopropanolamine, 4,4′-dimethylaminobenzophenone (Michler ketone), 4,4′-diethylaminobenzophenone, 2-dimethylaminoethylbenzoic acid, 4-dimethylaminobenzoic acid Ethyl, 4-dimethylaminobenzoic acid (n-butoxy) ethyl, isoamyl 4-dimethylaminobenzoate, 2-ethylhexyl 4-dimethylaminobenzoate, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone Etc. can be used in combination.

  Among these photopolymerization initiators (D), benzyl dimethyl ketal, 1-hydroxycyclohexyl phenyl ketone, benzoyl isopropyl ether, 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, 2-hydroxy It is preferable to use 2-methyl-1-phenylpropan-1-one.

  About content of the said photoinitiator (D), it is preferable that it is 0.5-20 weight part with respect to 100 weight part of said photopolymerizable compounds (B), Especially 0.8-15 weight part. Parts, more preferably 1 to 10 parts by weight. If the content of the photopolymerization initiator (D) is too small, the curability tends to be poor and the physical properties tend to be unstable. If the content is too large, the low molecular weight component increases, the crosslinking density decreases, and water resistance, heat resistance, etc. There is a tendency to decrease.

[Others]
In the adhesive composition of the present invention, in addition to the above components, an antistatic agent, other acrylic adhesives, other adhesives, urethane resin, rosin, rosin ester, as long as the effects of the present invention are not impaired. Hydrogenated rosin ester, phenol resin, aromatic modified terpene resin, aliphatic petroleum resin, alicyclic petroleum resin, styrene resin, xylene resin and other tackifiers, polyol and other plasticizers, antioxidants, Mixing conventionally known additives such as leveling agents, rheology control agents, colorants, fillers, anti-aging agents, ultraviolet absorbers and functional dyes, and compounds that cause coloration or discoloration upon irradiation with ultraviolet rays or radiation. However, the blending amount of these additives is preferably 30% by weight or less, particularly preferably 20% by weight or less, based on the total composition.
In addition to the above additives, a small amount of impurities contained in the raw materials for producing the constituent components of the adhesive composition may be contained.

  Thus, the adhesive composition of the present invention is obtained. The adhesive composition of the present invention preferably functions as an adhesive by being cured by irradiation with active energy rays, and can be suitably used as an adhesive for bonding base sheets.

  The adhesive composition of the present invention has a viscosity at 25 ° C. of usually from 1 to 100,000 mPa · s, preferably from 10 to 50,000 mPa · s, from the viewpoint of coatability to a substrate. Especially preferably, it is 50-30,000 mPa * s. If the viscosity is too low, unevenness tends to occur during application to the substrate, and if it is too high, application to the substrate tends to be difficult.

  The adhesive composition of the present invention may contain a solvent or may be used as a solvent-free composition, but the solvent-free type that can omit the step of drying the solvent in the adhesive. It is preferable to use it as a composition. In addition, the density | concentration in the case of containing a solvent is 3-90 weight% normally as solid content of an adhesive agent, Preferably it is 5-80 weight%, Especially preferably, it is 10-70 weight%. If the concentration is too low, the leveling property tends to decrease when applied to the substrate, and if it is too high, the viscosity tends to increase, making it difficult to apply. Examples of such solvents include alcohols such as methanol, ethanol, propanol, n-butanol and i-butanol, ketones such as acetone, methyl isobutyl ketone, methyl ethyl ketone and cyclohexanone, cellosolves such as ethyl cellosolve, toluene, xylene and the like. Aromatics, glycol ethers such as propylene glycol monomethyl ether, acetates such as methyl acetate, ethyl acetate, and butyl acetate, diacetone alcohol, and the like. These solvents may be used alone. Two or more kinds may be used in combination.

<Laminated body>
In the present invention, it is preferable that the base sheet [I] and the base sheet [II] are further laminated via a cured product of the adhesive composition. When the laminated body is obtained by laminating the base sheet [I] and the base sheet [II] using the adhesive composition of the present invention and curing, the peeling of the adhesive layer and the like is more likely. A laminate having excellent stability over time can be obtained.

  As the base sheet [I], at least one surface of the sheet has a convex surface with a surface roughness Ra of 0.1 to 100 μm, and the convex surface has a plurality of convex portions. The height of may be constant or different. Examples of the convex shape include dots, stripes, and lattices, and a stripe shape is particularly preferable from the viewpoint of both optical properties and adhesiveness.

  The base sheet [I] is a lens sheet in which convex lenses formed in one axial direction are arranged adjacent to each other, a so-called prism sheet, or a diffusion sheet in which irregularities are randomly formed. It is particularly preferred. Examples of the prism sheet include a prism sheet having a pitch of 60 μm, an average height of unevenness of 30 μm, and a vertex angle of a convex portion of 90 degrees (right angle).

  The measurement of the surface roughness Ra (μm) is in accordance with JIS B 0601 (1982), centerline average roughness. In the case of a prism sheet or a diffusion sheet, the average unevenness height corresponds to this. To do.

  Various known aspects can be adopted as the material and manufacturing method of such a base sheet [I]. For example, a sheet-shaped resin material extruded from a die is transferred to a concave transfer roller (with a reverse surface of the convex surface formed on the surface) that rotates at substantially the same speed as the extrusion speed of the resin material. A method for producing a resin sheet can be employed in which a pressure is sandwiched between nip roller plates arranged opposite to each other and rotated at the same speed, and the uneven shape on the surface of the transfer roller is transferred to a resin material.

  Moreover, the manufacturing method of the resin sheet which laminates | stacks the transcription | transfer mold board (stamper) in which the inversion type | mold of the convex part surface is formed on the surface by hot press, and is press-molded by thermal transfer is employable.

  As a resin material used in such a manufacturing method, a thermoplastic resin can be used. For example, polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyester, polyolefin, acrylic, polystyrene, polycarbonate Polyamide, PET (polyethylene terephthalate), biaxially stretched polyethylene terephthalate, polyethylene naphthalate, polyamideimide, polyimide, aromatic polyamide, cellulose acylate, cellulose triacetate, cellulose acetate propionate, cellulose diacetate, etc. It is done.

  Further, as another manufacturing method, the unevenness on the surface of a concavo-convex roller (inverted type of convex surface is formed on the surface) is transferred and formed on the surface of a transparent film (for example, a film made of the thermoplastic resin). A resin sheet manufacturing method can be employed.

  On the other hand, as the base sheet [II], if at least one side of the sheet has a flat surface, the other side may have a convex shape shown in the base sheet [I]. Good. Here, the flat surface means a flat surface having no unevenness, and preferably has a surface roughness Ra of less than 0.1 μm. The lower limit value of the surface roughness Ra is usually 0.001 μm.

  Examples of such a base sheet [II] include polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyester, polyolefin, acrylic, polystyrene, polycarbonate, polyamide, PET (polyethylene terephthalate), and PEN (polyethylene). Naphthalate), polymethyl methacrylate, polyetheretherketone, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, biaxially stretched polyethylene terephthalate, polyamideimide, polyimide, aromatic polyamide, cellulose acylate, cellulose triacetate, cellulose A known transparent film made of a material such as acetate propionate or cellulose diacetate can be used. Of these, polyesters such as polyethylene terephthalate and polyethylene naphthalate, acrylics such as cellulose acylate and polymethyl methacrylate, and polyolefins such as polycarbonate, polypropylene and cyclic polyolefin can be preferably used.

  Moreover, as base material sheet [II], the sheet | seat one side is a convex part surface shown by said base material sheet [I], and the sheet | seat whose other surface is a flat surface can also be used. In particular, in order to obtain an optical sheet, the substrate sheet [II] is preferably at least one of a prism sheet and a diffusion sheet.

In order to obtain a more excellent optical sheet, both the base sheet [I] and the base sheet [II] are prism sheets, or the base sheet [I] is a diffusion sheet and the base sheet [II]. ] Is a prism sheet, the base sheet [I] is preferably a prism sheet, and the base sheet [II] is preferably a diffusion sheet.
The adhesive composition of the present invention can have a very excellent adhesive force in bonding between prism sheets, which has conventionally been difficult to obtain sufficient adhesive force, and in bonding a prism sheet and a diffusion sheet.

  When both the base sheet [I] and the base sheet [II] are prism sheets, both are arranged in a direction in which the axes of the convex lenses (prisms) are substantially orthogonal. That is, when the axis of the convex lens of the prism sheet of the base sheet [I] is arranged in the vertical direction, the axis of the convex lens of the prism sheet of the base sheet [II] is arranged in the parallel direction. .

  A cross-sectional view of one preferred embodiment of the laminate of the present invention is shown in FIG. The laminated body shown in FIG. 1 is an optical sheet in which a diffusion sheet 1, a prism sheet 2, an adhesive composition cured body 5, a prism sheet 3, and a diffusion sheet 4 are laminated in this order from the bottom. The form in which the base sheet [I] and the base sheet [II] are both prism sheets is exemplified between the prism sheet 2 and the prism sheet 3, and the base sheet [I] is a prism sheet. The form in which the base sheet [II] is a diffusion sheet is exemplified between the prism sheet 3 and the diffusion sheet 4, and further, the base sheet [I] is a diffusion sheet, and the base sheet [II] is a prism sheet. The form which is is illustrated between the diffusion sheet 1 and the prism sheet 2. In addition, the figure shown in detail about bonding of this diffusion sheet 1 and the prism sheet 2 is shown in FIG.

  FIG. 2 is an exploded perspective view for explaining the laminated body shown in FIG. 1 (the cured body 5 is not shown), and a cross section obtained by cutting the prism sheets 2 and 3 along XX ′ shown in FIG. The figure is shown in FIG.

  Here, the diffusion sheet 1 and the diffusion sheet 4 of FIGS. 1 and 2 have light diffusibility on the surface (one side) of a transparent film (support) such as a PET film, a polycarbonate film, or polystyrene, for example. A sheet in which a plurality of beads are fixed with a binder such as an acrylic resin, an epoxy resin, a urethane resin, or an olefin resin, and has a predetermined light diffusion performance. The diffusion sheets 1 and 4 are mainly used for the purpose of reducing luminance unevenness in the backlight surface.

  Examples of the beads include acrylic beads, silica beads, barium sulfate, titanium oxide, and calcium silicate. For example, TDF-127 (manufactured by Toray Sehan Co., Ltd.), Opulse BS-080 (manufactured by Keiwa Co., Ltd.), D141 (manufactured by Tsujiden Co., Ltd.) and the like can be mentioned.

  The average particle size of the beads is preferably 100 μm or less, particularly preferably 50 μm or less, and further preferably 25 μm or less. Further, it is preferable that the diffusion sheet 1 and the diffusion sheet 4 have different average particle diameters of beads and have different light diffusion performance.

  The prism sheet 2 and the prism sheet 3 are optical sheets in which an array-like prism pattern 7 is provided on the surface of a base material 6 such as a PET film, a polycarbonate film, or polystyrene. It is used for the purpose of collecting light and improving luminance.

  Examples of the material of the prism pattern 7 include acrylic photopolymer, polycarbonate, fluorene resin, and the like, but are not limited thereto. Further, the prism pattern 7 does not have to be strictly a prism shape, and may be a wave film shape or a downward prism shape having an R shape at the top.

  In the laminate of FIG. 1, the prism sheets 2 and 3 are bonded to each other by the cured body 5 of the adhesive composition of the present invention. Specifically, the adhesive composition is thinly coated on the flat surface of one prism sheet 3, and this prism sheet 3 is used to form the prism pattern surface (convex surface) of the other prism sheet 2 using the adhesive composition. Are bonded together and cured by curing the adhesive composition. At this time, the prism sheets 2 and 3 are point-bonded or line-bonded by the convex portions of the prism sheet 2.

  Further, the diffusion sheet 1 and the prism sheet 2 of FIG. 1 may be bonded by the cured body 5 of the adhesive composition of the present invention. Specifically, the adhesive composition is thinly coated on the flat surface of one prism sheet 2, and the prism sheet 2 is bonded to the convex surface of the diffusion sheet 1 using the adhesive composition, and the above-mentioned adhesion It can also adhere | attach by hardening an agent composition (FIG. 5).

  FIG. 3 is a cross-sectional view of the prism sheets 2 and 3 in the exploded perspective view of FIG. 2 cut along X-X ′ shown in FIG. 2. As shown in the cross-sectional view of FIG. 3, the prism patterns 7 of the prism sheets 2 and 3 are each composed of a plurality of convex portions (prisms) having the same uneven height. In addition, the prism patterns 7 of the prism sheet 2 and the prism sheet 3 may be prism patterns having the same uneven height, or may be different.

  As another embodiment, as shown in the prism sheet 2 of FIG. 4, a plurality of convex portions (prisms) 8 that are one step higher than the prism pattern 7 having the same uneven height are arranged in the prism pattern 7 at regular intervals. A prism sheet may be used.

  As shown in FIG. 4, when a plurality of convex portions (prisms) 8 that are one step higher than the prism pattern 7 are arranged at regular intervals, only the higher convex portions (prisms) 8 are bonded. Among the plurality of convex portions, the interval at which the higher convex portion is provided is 1/3 (one of the three convex portions is set as a higher convex portion) to 1/10 from the viewpoint of improving the luminance. Is preferred.

  6 is a cross-sectional view of the diffusion sheet 1 and the prism sheet 2 in the exploded perspective view of FIG. 2 cut along X-X ′ shown in FIG. 2. 6 corresponds to the exploded view of FIG. 5 showing the combination of the diffusion sheet 1 and the prism sheet 2 in detail. As shown in the cross-sectional view of FIG. 6, the prism pattern 7 of the prism sheet 2 has a regular pattern, and the diffusion layer 9 of the diffusion sheet 1 has a random pattern. The prism pattern 7 may be uniform in height and shape, or non-uniform. Further, the shape of the diffusion layer 9 may be random or regular.

<Method for producing laminate>
As a manufacturing method of the laminated body of this invention, the process of laminating | stacking base material sheet [I] and base material sheet [II] using the said adhesive composition, The process of hardening | curing the said adhesive composition, Is provided. Specifically, after the liquid adhesive composition is uniformly applied to the flat surface of the base sheet [II], it is then applied to the convex surface of the base sheet [I] via the adhesive composition. The adhesive composition is cured by bonding, pressure bonding, and active energy ray irradiation, and a laminate is obtained.

  In applying such an adhesive composition to the flat surface of the base sheet [II], for example, a reverse coater, a gravure coater (direct, reverse or offset), a bar reverse coater, a roll coater, a die coater, a bar coater, A rod coater or the like can be used, or coating by a dipping method can be performed.

  For such bonding and pressure bonding, for example, a roll laminator or the like can be used, and the pressure is selected from a range of 0.1 to 10 MPa.

  For such active energy ray irradiation, rays such as far ultraviolet rays, ultraviolet rays, near ultraviolet rays, infrared rays, electromagnetic waves such as X rays and γ rays, electron beams, proton rays, neutron rays, etc. can be used. Curing by ultraviolet irradiation is advantageous from the standpoint of availability of the device and price. In addition, when performing electron beam irradiation, it can harden | cure even without using the said photoinitiator (D).

As a light source for such ultraviolet irradiation, a high pressure mercury lamp, an electrodeless lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a xenon lamp, a metal halide lamp, a chemical lamp, a black light, an LED lamp, or the like is used.
Such ultraviolet irradiation is performed under conditions of ^{2 to} 3000 mJ / cm ² , preferably 10 to 2000 mJ / cm ² .

Especially in the case of the high-pressure mercury lamp, for example, 5~3000mJ / cm ^2, preferably at the conditions of 50~2000mJ / cm ^2.
Moreover, in the case of the said electrodeless lamp, it is 2-2000 mJ / cm < ² >, for example, Preferably it is performed on the conditions of 10-1000 mJ / cm < ² >.

  The irradiation time varies depending on the type of the light source, the distance between the light source and the coating surface, the coating thickness, and other conditions, but may be usually from several seconds to several tens of seconds, and in some cases, may be a fraction of a second. On the other hand, in the case of the electron beam irradiation, for example, an electron beam having an energy in the range of 50 to 1000 keV is used, and the irradiation amount is preferably 2 to 50 Mrad.

  Irradiation direction of such active energy rays (ultraviolet rays, electron beams, etc.) can be irradiated from any appropriate direction, but is not a convex surface of the base sheet [I] in terms of preventing deterioration of the laminate. It is preferable to irradiate from the surface side.

  The thickness of the adhesive layer in the laminate of the present invention obtained as described above is usually 0.01 to 20 μm, preferably 0.01 to 10 μm, particularly preferably 0.01 to 7 μm, more preferably 0.1 to 5 μm. It is. If the thickness is too thin, the cohesive strength of the adhesive force itself cannot be obtained, and the adhesive strength tends to be not obtained. If the thickness is too thick, the durability of the laminate tends to be reduced due to cracking or the like.

  The adhesive composition of the present invention is an adhesive having excellent adhesive strength at the initial stage and with the passage of time, and is obtained from the convex surface of the base sheet [I] having a convex surface and the base sheet [II] having a flat surface. Used for bonding flat surfaces, but is particularly suitable for bonding prism sheets (illustrated in FIG. 3), for bonding prism sheets and diffusion sheets (illustrated in FIG. 6), and for prisms. The sheet exhibits good adhesiveness without being influenced by the moisture content of the sheet itself, and does not require a drying step, and is excellent in production efficiency of the laminate.

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated further more concretely, this invention is not limited to a following example, unless the summary is exceeded.
In the examples, “parts” and “%” mean weight basis.

  Prior to the examples and comparative examples, the components of the adhesive composition shown below and the substrate sheet were prepared.

<Urethane (meth) acrylate compound (A)>
[Synthesis Example of Urethane Acrylate (A-1)]
A 500 ml reaction vessel equipped with a stirrer was charged with 0.3 g of dibutyltin dilaurate, 0.2 g of 4-methoxyphenol as a polymerization inhibitor, and 166 g of polytetramethylene glycol (molecular weight 650). Was heated to 40 ° C.
200 g of hydrogenated diphenylmethane diisocyanate was gradually added to the reaction solution, and the temperature was raised to 60 ° C. over 1 hour. The reaction was continued until the free NCO% became 8.6% while continuing the reaction at 60 ° C., and then 134 g of 2-hydroxyethyl acrylate was added, and the reaction was continued until the free NCO% became 0.5% or less. A bifunctional polyether urethane acrylate was obtained.
The obtained bifunctional polyether urethane acrylate had a weight average molecular weight of 3,000 and a viscosity of 12,000 mPa · s / 60 ° C.

[Synthesis Example of Urethane Acrylate (A-2)]
Calculated from 366 g (1.40 mol) of 4,4′-dicyclohexylmethane diisocyanate and 469 g of polyether diol (linear structure; hydroxyl value 167 mgKOH / g; hydroxyl value) in a flask equipped with an internal thermometer, stirrer and condenser. Number average molecular weight 672; 0.70 mol), 0.1 g of dibutyltin dilaurate was charged as a reaction catalyst and reacted at 70 ° C. When the residual isocyanate group becomes 7.0% or less, the mixture is cooled to 60 ° C., 165 g (1.42 mol) of 2-hydroxyethyl acrylate, and 0.4 g of methoxyphenol as a polymerization inhibitor are further charged, and the reaction is performed at 60 ° C. The reaction was terminated when the residual isocyanate group became 0.3% or less, and the urethane (meth) acrylate compound (A-2) having an ether structure (weight average molecular weight; 5,000, viscosity; 20, 000 mPa · s / 60 ° C.).

[Synthesis Example of Urethane Acrylate (A-3)]
In a flask equipped with an internal thermometer, a stirrer, and a condenser tube, 301 g (1.35 mol) of isophorone diisocyanate, 540 g of polycarbonate diol (linear structure; hydroxyl value 140.5 mgKOH / g; number average molecular weight calculated from hydroxyl value) 799; 0.68 mol), 0.1 g of dibutyltin dilaurate was charged as a reaction catalyst and reacted at 80 ° C. When the residual isocyanate group became 6.8% or less, the mixture was cooled to 60 ° C., 159 g (1.37 mol) of 2-hydroxyethyl acrylate, and 0.4 g of methoxyphenol as a polymerization inhibitor were further added, and reacted at 60 ° C. The reaction was terminated when the residual isocyanate group became 0.3% or less, and the urethane (meth) acrylate compound (A-3) having a carbonate structure (weight average molecular weight; 5,000, viscosity; 50, 000 mPa · s / 60 ° C.).

<Photopolymerizable compound (B)>
(B-1) Dimethylacrylamide (manufactured by Kojinsha, DMAA)
(B-2) Polyethylene glycol di (meth) acrylate (manufactured by NOF Corporation, Blemmer ADE-200)
(B-3) 2-ethylhexyl acrylate (Mitsubishi Chemical Corporation)
(B-4) benzyl acrylate (Osaka Organic Chemical Co., Ltd., Biscoat # 160)
(B-5) Cyclic trimethylolpropane formal acrylate (Osaka Organic Chemical Co., Ltd., Biscoat # 200)
(B-6) Diethylacrylamide (KAA Chemicals, DEAA)
(B-7) Trimethylolpropane triacrylate (manufactured by Toagosei Co., Ltd., M-309)

<(Meth) acrylic resin (C)>
(C-1) Acrylic polymer (manufactured by Toagosei Co., Ltd., UP-1010)
(C-2) Acrylic polymer (Mitsubishi Rayon, Dianal BR-83)

<Photopolymerization initiator (D)>
(D-1) 1-hydroxycyclohexyl phenyl ketone (manufactured by BASF, Irgacure 184)

<Base sheet [I], [II]>
Moreover, the prism sheet was prepared as base material sheet [I] and [II]. Such a prism sheet has a pitch of 50 μm, an average height of unevenness of 25 μm (surface roughness Ra of 25 μm), and an apex angle of the convex part of 90 degrees.

[Example 1]
15 parts urethane acrylate (A-1), 60 parts dimethylacrylamide (B-1), 10 parts polyethylene glycol di (meth) acrylate (B-2), 5 parts 2-ethylhexyl acrylate (B-3), acrylic polymer 10 parts of (C-1) and 2 parts of a photopolymerization initiator (D-1) were stirred and mixed in a flask to obtain an adhesive composition. A solution obtained by diluting 50% of the adhesive composition with methyl ethyl ketone on the flat surface of the prism sheet was coated with a bar coater to a thickness of 1 μm after drying, and dried for 10 minutes with a dryer at 80 ° C. On the obtained prism sheet with an adhesive layer, the prism pattern surface of another prism sheet was bonded with a 2 kg hand roller to obtain a film. The obtained film was exposed to 500 mJ / cm ² with a UV irradiator (high pressure mercury lamp), the adhesive was cured, and a laminated sheet in which two prism sheets were bonded was obtained.

[Examples 2 to 6 and Comparative Examples 1 and 2]
In Example 1, a laminated sheet having two prism sheets bonded thereto was obtained in the same manner as in Example 1 except that the composition was as shown in Table 1 below.

  Using the laminated sheet obtained above, performance evaluation was performed as follows, and the results are also shown in Table 1.

[Adhesion evaluation]
The laminated sheet obtained above was cut into 15 cm × 2.5 cm, and peeled in the direction perpendicular to the convex stripe direction (so as to peel one stripe at a time) at a room temperature of 23 ° C., 180 ° peel strength (N / 25 mm) was measured according to the method of measuring the adhesive strength of JIS Z 0237.

  From the results of Table 1 above, the laminated sheets of Examples 1 to 6 each have a high 180 ° peel strength, compared to the laminated sheets of Comparative Examples 1 and 2 that do not contain the urethane (meth) acrylate compound (A). , Both were found to have excellent adhesion.

  The adhesive composition of the present invention is very adhesive in bonding of the convex surface of the base sheet [I] having a convex surface and the flat surface of the base sheet [II] having a flat surface. Since it is excellent, it can be used for, for example, bonding of various optical films or sheets, and bonding of electronic parts, precision devices, packaging materials, display materials, and the like, in addition to the prism sheet adhesive application.

DESCRIPTION OF SYMBOLS 1 Diffusion sheet 2 Prism sheet 3 Prism sheet 4 Diffusion sheet 5 Hardened | cured material of adhesive composition 6 Base material 7 Prism pattern 8 High convex part (prism)
9 Diffusion layer

Claims (10)

  An adhesive composition for bonding a convex surface of a base sheet [I] having a convex surface with a surface roughness Ra of 0.1 to 100 μm and a flat surface of a base sheet [II] having a flat surface. An adhesive composition comprising a urethane (meth) acrylate compound (A).   Urethane (meth) wherein the urethane (meth) acrylate compound (A) is a reaction product of a hydroxyl group-containing (meth) acrylate compound (a1), a polyvalent isocyanate compound (a2), and a polyol compound (a3). The adhesive composition according to claim 1, which is an acrylate compound (A1).   The adhesive composition according to claim 1, further comprising a photopolymerizable compound (B) other than the urethane (meth) acrylate compound (A).   The adhesive composition according to claim 3, wherein the photopolymerizable compound (B) contains a photopolymerizable compound (B1) containing a proton-accepting group.   The content ratio of the urethane (meth) acrylate-based compound (A) and the photopolymerizable compound (B) is 1: 2 to 1: 3 in weight ratio. The adhesive composition according to item.   Furthermore, (meth) acrylic-type resin (C) is contained, The adhesive composition as described in any one of Claims 1-5 characterized by the above-mentioned.   Furthermore, a photoinitiator (D) is contained, The adhesive composition as described in any one of Claims 1-6 characterized by the above-mentioned.   The base sheet [I] and the base sheet [II] are stacked via an adhesive made of the adhesive composition according to any one of claims 1 to 7. body.   The laminate according to claim 8, wherein the substrate sheet [I] and the substrate sheet [II] are at least one of a prism sheet and a diffusion sheet, respectively.   The process of laminating | stacking base material sheet [I] and base material sheet [II] using the adhesive composition as described in any one of Claims 1-7, The process of hardening | curing the said adhesive composition. The manufacturing method of the laminated body characterized by the above-mentioned.

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