KR102062177B1 - Ultraviolet light curing adhesive composition and adhesive layer - Google Patents

Abstract

The pressure-sensitive adhesive composition of the present invention does not require drying of the solvent due to the non-solvent that can be used in touch panels, plasma display panels, and the like, and can form the pressure-sensitive adhesive layer of a thick film by one coating. In addition, the pressure-sensitive adhesive composition of the present invention is excellent in durability under the conditions of transparency, adhesion, heating and humidification, and further provides an ultraviolet curable pressure-sensitive adhesive composition that can be peeled off without leaving after being glued together. The polyfunctional urethane (meth) acrylate of (A) weight average molecular weights 10,000-10,000 whose solvent content is less than 1 weight%, the viscosity of 25 degreeC is 100-10,000 mPa * s, and a hue is Gardner color 1 or less. An ultraviolet curable adhesive composition containing an oligomer, (B) tackifier, (C) monofunctional epoxy ester (meth) acrylate, and (D) photoinitiator.

Description

UV curable pressure-sensitive adhesive composition and adhesive layer {ULTRAVIOLET LIGHT CURING ADHESIVE COMPOSITION AND ADHESIVE LAYER}

The present invention relates to an ultraviolet curable pressure sensitive adhesive composition and an adhesive layer.

In recent years, display devices such as in-vehicle vehicles, outdoor instruments, displays such as PCs, TVs, and the like are required to be lightened or flattened, so that liquid crystal display devices are widely used, and the demand thereof is increasing day by day. In particular, in recent years, liquid crystal displays have been used in digital information devices such as ATMs, vending machines, mobile phones, portable information terminals, digital audio players, portable game machines, electronic dictionaries, copiers, fax machines, and car navigation systems. The touch panel used is used a lot.

The touch panel is an electronic component combining a display device and a location input device, and displays image information received from an external device on a liquid crystal display, and simultaneously detects contacted screen position information and outputs it as an information signal to the outside. The position input device of the touch panel mainly includes a control method such as a resistive film method, a capacitive method, an electromagnetic induction method, an optical method, and an acoustic method. In particular, the resistive film method and the capacitive method are common control methods.

The resistive touch panel and the capacitive touch panel are functional in addition to display devices such as films, glass, liquid crystals, and the like having a transparent conductive layer such as an outermost protective film, glass, and an indium oxide (hereinafter referred to as "ITO") film. It consists of sheets. Among these, a film, glass, and a functional sheet are normally matched with an optical adhesive.

As described above, the optical pressure-sensitive adhesive used in the touch panel application is adhered to the front protective film or glass and the film or glass having a transparent conductive layer, or the film or glass having a transparent conductive layer or a display device such as a liquid crystal. Since it is used for sticking and the like, optical performance such as transparency and weather resistance is required.

As such an optical adhesive, the optical adhesive composition manufactured from various high molecular weight acrylic polymers and various crosslinking agents is proposed (refer patent document 1 and 2).

On the other hand, in recent years, a thick adhesive layer having a thickness of 100 µm or more is required for improving impact resistance of a touch panel, absorption of a printing step of a front surface protective film or glass, and the like. The pressure-sensitive adhesive layer of such a thick film (having a thickness of 100 μm or more) can be obtained by forming a pressure-sensitive adhesive layer having a thickness of 25 μm or 50 μm from the optical pressure-sensitive adhesive composition, and laminating them together. However, since this method has a large number of processes, there is a problem in that the cost is high and the transparency is lowered by sticking together. On the other hand, when attempting to form the adhesive layer which has a thickness of 100 micrometers or more by one coating, there exists a subject which cannot satisfy performance as optical for the foam | bubble when a coating agent is dried, and foaming arises in a coating film.

As a method of obtaining the adhesive layer which has a thickness of 100 micrometers or more by single coating, without using foaming, use of a non-solvent type adhesive composition is considered. As a solvent-free adhesive structure, the ultraviolet curable non-solvent-type adhesive composition containing various (meth) acrylate oligomers or (meth) acrylate monomers is proposed (refer patent document 3).

However, the solvent-free pressure-sensitive adhesive composition has problems in performance as an adhesive such as transparency, adhesive force, durability under heating and humidification conditions, and in case of a positional difference in case of sticking, leaving a paste in case of peeling.

Japanese Patent Laid-Open No. 2011-195651 Japanese Patent Laid-Open No. 2011-225835 Publication No. 2005-530024

The present invention is a solvent-free optical pressure-sensitive adhesive composition for use in touch panels and the like, the pressure-sensitive adhesive layer of a thick film can be formed by one coating, and excellent in transparency, adhesion, heating and humidification conditions, and excellent in durability, and furthermore, It is a main subject to provide the ultraviolet curable adhesive composition which can be peeled off without leaving.

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining, in an ultraviolet curable adhesive structure, the solvent content is less than 1 weight%, the viscosity of 25 degreeC adjusts to 100-10,000 mPa * s, and a hue is adjusted to Gardner color 1 or less, (A) weight average molecular weight (The polystyrene conversion value of gel permeation chromatography, the same hereafter.) The polyfunctional urethane (meth) acrylate oligomer of 10,000-100,000, (B) tackifier, (C) monofunctional epoxy ester (meth) It was discovered that the said subject can be solved by mix | blending an acrylate and (D) photoinitiator.

Moreover, the present inventors also found that when the said adhesive composition is used, the adhesive layer which can solve the said subject can be provided.

That is, this invention relates to the following ultraviolet curing adhesive composition and adhesion layer.

1.A UV curable pressure-sensitive adhesive composition having a solvent content of less than 1% by weight, a viscosity of 25 ° C. of 100 to 10,000 mPa · s, and a hue of Gardner Color 1 or less, including the following (A) to (D):

(A) a polyfunctional urethane (meth) acrylate oligomer having a weight average molecular weight of 10,000 to 100,000;

(B) tackifier;

(C) monofunctional epoxy ester (meth) acrylate; And

(D) Photoinitiator.

2. The polyfunctional urethane (meth) acrylate oligomer according to item 1, wherein the component (A) is obtained by reacting a polyether polyol, a polyisocyanate and a hydroxyl group-containing (meth) acrylate or an isocyanate group-containing (meth) acrylate. UV curable pressure-sensitive adhesive composition.

3. The ultraviolet curable pressure sensitive adhesive composition according to item 1 or 2, wherein the component (B) is a tackifier having a color tone of Gardner color 1 or less.

4. The method according to any one of items 1 to 3, wherein the components (A) to (D) are based on the weight part in the adhesive composition (A) :( B) :( C) :( D) = The ultraviolet curable adhesive composition mix | blended in the ratio of 10-60: 0.5-15: 15-8.4: 0.1-10.

5. The adhesion layer obtained by hardening | curing the ultraviolet curable adhesive composition of any one of Claims 1-4.

6. The pressure-sensitive adhesive layer of claim 5, wherein the pressure-sensitive adhesive layer has a thickness of 10 to 1000 µm.

The pressure-sensitive adhesive composition of the present invention does not require drying of the solvent due to the non-solvent that can be used in a touch panel, a plasma display panel, and the like, and can form the pressure-sensitive adhesive layer of a thick film by one coating. In addition, the pressure-sensitive adhesive composition of the present invention is excellent in durability under the conditions of transparency, adhesive force, heating and humidification, and can be peeled off without leaving a paste after fitting more. Therefore, the adhesive layer of this invention formed from the said adhesive composition is excellent as adhesiveness, transparency, and its durability, and is suitable as an adhesive layer used for a touch panel, a plasma display panel, etc.

The present invention has a polyfunctional urethane (meth) acrylate having a solvent content of less than 1% by weight, a viscosity of 25 ° C of 100 to 10,000 mPa · s, a color tone of Gardner color 1 or less, and a weight average molecular weight of 10,000 to 100,000. Oligomer (henceforth "(A) component"), (B) tackifier (henceforth "(B) component"), (C) monofunctional epoxy ester (meth) acrylate (henceforth, "( C) component ") and (D) a photoinitiator (henceforth" (D) component ").

When the solvent content is 1% by weight or more, in order to form an adhesive layer of a thick film (thickness of 100 μm or more), there is a problem that foaming occurs when the coating solvent is dried and cured, and bubbles are generated in the coating film.

When the said viscosity is out of the range of 100-10,000 mPa * s, it becomes difficult to form the adhesion layer of a thick film by one coating at normal temperature and normal pressure.

By making the color tone of the said adhesive composition into 1 or less in Gardner color, the adhesive layer excellent in transparency and color tone can be formed.

By making the weight average molecular weight of the said (A) component 10,000 or more, the adhesive force of an adhesion layer can be improved. Moreover, by making the weight average molecular weight of (A) component 100,000 or less, the viscosity of a polyfunctional urethane (meth) acrylate oligomer can be reduced, and the handling of an adhesive improves.

The said (A) component can be obtained by reaction of a polyol, polyisocyanate, and hydroxyl-containing (meth) acrylate or an isocyanate-group containing (meth) acrylate.

There is no restriction | limiting in particular as said polyol, Polyether polyols, such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and these copolymers; Polyester polyols such as polycondensates of adipic acid and polyhydric alcohols, polycondensates of sebacic acid and polyhydric alcohols, polycondensates of phthalic acid and polyhydric alcohols, and polyadditives obtained by ring-opening reactions of lactones and polyhydric alcohols; Polycarbonate polyols obtained from the reaction of diols such as 1,3-propanediol, 1,4-butanediol, 1,5-pentane diol, 1,6-hexanediol, and cyclohexanedimethanol with phosgene; Polyolefin polyols, such as a polybutadiene diol and a hydrogenated polybutadiene polyol, etc. are mentioned. These may be individual or mixed. In particular, the use of polyether polyols is preferable from the viewpoint of low viscosity of the pressure-sensitive adhesive and high adhesion of the pressure-sensitive adhesive layer.

The polyisocyanate is 2,4-triene diisocyanate, 2,6-triene diisocyanate, 1,3-xylene diisocyanate, diphenylmethane-4,4-diisocyanate, 3-methyl-diphenylmethane diisocyanate, Aromatic diisocyanate compounds such as 1,5-naphthalene diisocyanate; Aliphatic diisocyanate compounds such as dicyclohexyl methane diisocyanate, isophorone diisocyanate and hexamethylene diisocyanate; These dimers, etc. are mentioned. These may be individual or mixed. In particular, the use of aliphatic diisocyanate is preferable in view of low viscosity of the pressure-sensitive adhesive, high adhesion of the pressure-sensitive adhesive layer, and durability.

Isocyanate group-containing (meth) acrylates in a terminal hydroxyl group-containing urethane prepolymer obtained by reacting a hydroxyl group-containing (meth) acrylate with a terminal isocyanate group-containing urethane prepolymer obtained by reacting the polyol and a polyisocyanate. By reacting a rate, a polyfunctional urethane (meth) acrylate oligomer can be obtained.

The hydroxyl group-containing (meth) acrylate is 2-hydroxy (meth) acrylate, hydroxy propyl (meth) acrylate, 4-hydroxy (meth) acrylate, 2-hydroxy-2-methylpropyl (meth) Monofunctional (meth) acrylates such as acrylate; Polyfunctional (meth) acrylates such as pentaerythritol triacrylate and dipentaerythritol pentaacrylate; Epoxy ester (meth) acrylate etc. which are obtained by making an epoxy compound and (meth) acrylic acid react are mentioned. These may be individual or mixed.

Examples of the isocyanate group-containing (meth) acrylate include 2-isocyanate ethyl (meth) acrylate and 1,1- (bisacryloyloxymethyl) ethyl isocyanate. These may be individual or mixed.

The average number of functional groups of the polyfunctional urethane (meth) acrylate oligomer is at least 1.5, preferably at least 1.8. The average functional group number of a urethane (meth) acrylate oligomer is the number which shows how many average acryloyl groups exist in 1 molecule of urethane (meth) acrylate oligomers. When synthesize | combining a urethane (meth) acrylate oligomer, the average functional group number of a urethane (meth) acrylate oligomer is controlled by controlling the reaction amount of a hydroxyl-containing (meth) acrylate compound or an isocyanate group containing (meth) acrylate compound. can do. The optical adhesive which is excellent in durability can be obtained by using urethane (meth) acrylate oligomer of average functional group number 1.5 or more.

The said (B) component is a tackifier. Specific examples of the component (B) include petroleum resin phenol resins, xylene resins, coumarone resins, rosin resins, terpene resins, hydrogenated petroleum resins, hydrogenated rosin resins, and hydrogenated terpene resins. Especially, it is preferable that a hue is gardner color 1 or less normally. As a hue of Gardner color 1 or less, hydrogenated petroleum resin and hydrogenated rosin-type resin are mentioned, for example. These hydrogenated resins usually improve the transparency of the pressure-sensitive adhesive for optics and the pressure-sensitive adhesive layer which are excellent in transparency in that the color tone is Gardner color 1 or less. Moreover, since these hydrogenation resins also have little polymerization inhibition in the case of superposition | polymerization by ultraviolet irradiation, they are used, and it becomes an optical adhesive excellent in sclerosis | hardenability by using these.

As said hydrogenated rosin-type resin, if the rosin-type resin was hydrogenated, it will not specifically limit but a well-known thing can be used. Examples of the rosin-based resins include polymerization, denaturation, and disproportionation of natural rosin, in addition to natural rosin, such as gum rosin, tall oil rosin, and wood rosin. Rosin metals obtained by reacting rosin processed by at least one method selected from the reaction and esterification (hereinafter referred to as "process rosin"), natural rosin or processed rosin with metals such as calcium, magnesium and zinc Etc. can be mentioned.

The manufacturing method of the rosin (henceforth "polymerization rosin") processed by the polymerization method in the said processed rosin is not specifically limited, A well-known method can be employ | adopted. For example, there is a method of heating the natural rosin or the rosin processed by at least one method selected from denaturation, disproportionation reaction and esterification using a polymerization catalyst. It does not specifically limit as a polymerization catalyst, A well-known thing can be used. Specific examples of the polymerization catalyst include acids such as sulfuric acid, phosphoric acid and hydrofluoric acid; And metal halides such as boron fluoride, aluminum chloride and zinc chloride.

The manufacturing method of the rosins (henceforth "modified rosin") processed by the said modification method is not specifically limited, What is necessary is just to employ | adopt a well-known method. Usually, the method of mixing and heating natural rosin, phenols, or unsaturated fatty acid is used. It does not specifically limit as said phenols, Specifically, a phenol, alkyl phenol, etc. are mentioned, for example. It does not specifically limit as said unsaturated fatty acid, Specifically, a fumaric acid, maleic acid (meth) acrylic acid, etc. are mentioned.

The manufacturing method of the rosin processed by the said disproportionation method (henceforth "disproportionated rosin") is not specifically limited, A well-known method may be employ | adopted. Usually, natural rosin or processed rosin is saponified by making it react for 2 to 6 hours at 220-250 degreeC, without adding hydrogen in presence of reduction catalysts, such as nickel, silver, and palladium, or a carbon catalyst.

The manufacturing method of the rosin (henceforth "a rosin ester") processed by the said esterification method is not specifically limited, A well-known method can be employ | adopted. Usually, there is a method of mixing natural rosin or processed rosin with alcohol and heating in the presence of an esterification catalyst, if necessary. Examples of the esterification catalyst include acid catalysts such as acetic acid and paratoluene sulfonic acid, and hydroxides of alkali metals such as lithium hydroxide, sodium hydroxide and potassium hydroxide; Hydroxides of alkaline earth metals such as calcium hydroxide and magnesium hydroxide; Metal oxides, such as calcium oxide, magnesium oxide, zinc oxide, lead oxide, and tin oxide, etc. can be used.

The alcohol may include an aliphatic monohydric or polyhydric alcohol having 1 to 20 carbon atoms. Such alcohols include, for example, methanol, ethanol, isopropyl alcohol, isoamyl alcohol, n-hexyl alcohol, 2-ethylhexyl alcohol, n-octyl alcohol, dodecyl alcohol, lauryl alcohol, stearyl alcohol, dihydroabi Monohydric alcohols such as ethyl alcohol; Dihydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol and neopentyl glycol; Trihydric alcohols such as glycerin, trimetholethane, and trimetholpropane; And tetrahydric alcohols such as pentaerythritol and diglycerin.

The said rosin-type resin may be used individually by 1 type, or may mix and use 2 or more types. Moreover, natural rosin etc. can also be processed using two or more methods of polymerization, denaturation, disproportionation reaction, and esterification. When manufacturing rosin-type resin through 2 or more types of methods, the order of the method is not specifically limited, It can follow a well-known method. For example, natural rosin or processed rosin may be modified after polymerization, or may be esterified after polymerization.

If the petroleum resin is hydrogenated with the hydrogenated petroleum resin of the said (B) component, it will not specifically limit, A well-known thing can be used. Examples of the petroleum resin include aliphatic petroleum resins, aromatic petroleum resins, and dicyclopentadiene petroleum resins, depending on the kind of the raw material monomer (oil component). Examples of the aliphatic petroleum resins include C5 petroleum resins and C5-C9 petroleum resins. As aromatic petroleum resin, C9 type petroleum resin etc. are mentioned. C5-based petroleum resin can be obtained by cationic polymerization reaction of C5-based petroleum fraction (for example, pentene, methyl butene, isoprene, cyclopentene, etc.). Although it does not specifically limit as C9 petroleum resin, Generally, C9 type petroleum fraction (for example, styrene, vinyl toluene, (alpha) -methyl styrene, indenes, etc.) obtained through cracking of naphtha is cationic polymerization reaction. The obtained one can be used. C5-C9 type petroleum resin copolymerizes the said C5 type petroleum fraction and C9 type petroleum fraction like C5 type petroleum resin manufacture. The dicyclopentadiene petroleum resin is obtained by thermal polymerization or cationic polymerization of dicyclopentadiene. These petroleum resins may be modified with a polar group such as a hydroxyl group or an ester group, usually by a known method. In addition, the hue of petroleum resin is about 5-15 Gardner normally.

The said (C) component can use various well-known thing which is a monofunctional epoxy ester (meth) acrylate obtained by making a monofunctional epoxy compound react with (meth) acrylic acid especially without restriction | limiting. As the (C) component, specifically, a monofunctional epoxy ester (meth) acrylate obtained by reacting phenylglycidyl ether and (meth) acrylic acid and (methylphenyl) phenylglycidyl ether and (meth) acrylic acid are reacted. Aromatic structures, such as the monofunctional epoxy ester (meth) acrylate which can be obtained, and the monofunctional epoxy ester (meth) acrylate which can be obtained by making (t-butylphenyl) phenyl glycidyl ether react with (meth) acrylic acid, Alkyl groups having 1 to 30 carbon atoms, such as monofunctional epoxy ester (meth) acrylates obtained by reacting (meth) acrylate and (ethylhexyl) glycidyl ethermethyl (meth) acrylate with (meth) acrylic acid And (meth) acrylates. Among these, the monofunctional epoxy ester (meth) acrylate which has an aromatic structure from the compatibility point of a urethane (meth) acrylate oligomer and a tackifier is preferable.

If the said (D) component is a photoinitiator which generate | occur | produces the radical decomposed | disassembled by ultraviolet irradiation, various well-known thing can be used especially without limitation. As (D) component, Photoinitiator, such as a benzoin compound, an acetophenone compound, an acyl phosphine oxide compound, a titanocene compound, a thioxene compound, an oxime ester compound; Photosensitizers, such as an amine and quinone, etc. are mentioned. As specific compounds, 2,2-dimethoxy-1,2-diphenylethan-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 2-hydroxy-2-methyl-1-phenyl-propane- 1-one, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1- [4- [4 -(2-hydroxy-2-methyl-propionyl) -benzyl] phenyl] -2-methyl-propane-1-one, 2-methyl-1- (4-methylthio phenyl) -2-morpholinopropane- 1-one, 2- (dimethylamino) -2-[(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone, 2,4,6-torrimethyl Benzoyl-diphenyl-phosphineoxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphineoxide, bis (η 5-2,4-cyclopentadien-1-yl) -bis (2,6- Difluoro-3- (1H-pyrrole-1-yl) -phenyl) titanium, 1,2-octanedione1- [4- (phenylthio) -2- (O-benzoyloxime)], ethanone 1 [ 9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl] -1- (0-acetyloxime), and the like. These may be used individually by 1 type, or may use 2 or more types together. Among them, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide and bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide are preferred because the curability of the pressure-sensitive adhesive composition is improved.

The said (A)-(D) component is based on a weight part in an adhesive composition, (A): (B): (C): (D) = 10-60: 0.5-15: 15-89.4: 0.1-10 of It is good to mix in ratio. Especially preferable compounding ratio is 20-35: 5-10: 30-70: 0.2-5. By making the mixture ratio of the said (A) component into the said range, the adhesive force of an adhesion layer can be improved and the handling of an adhesive can be improved at the same time. By making the mixture ratio of the said (B) component into the said range, the adhesive force of an adhesion layer can be improved and the remainder of the pool of an adhesion layer can be removed. By carrying out the mixing | blending ratio of the said (C) component in the said range, handling of an adhesive can be improved, an appropriate viscosity can be obtained simultaneously, and a thick film adhesion layer can be formed by single coating. By setting the blending ratio of the component (D) within the above range, it is possible to prevent the deviation of polymerization due to active energy ray irradiation such as ultraviolet rays, to prevent odor due to the decomposition products of the component (D), and to further color the cured product. Can be prevented.

The ultraviolet curable adhesive composition of this invention can be manufactured by mixing the said (A)-(D) component. The mixing method is not specifically limited, The order of addition of said (A)-(D) component is irrelevant.

Moreover, the adhesive composition of this invention can be made to contain various monofunctional or polyfunctional monomer as a diluent monomer in the range which does not lose the effect of this invention as needed.

As a specific example of the said monofunctional monomer, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (Meth) acrylate, t-butyl (meth) acrylate, n-pentyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate , Nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, lauryl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth (Meth) acrylate which has a C1-C30 alkyl group, such as) acrylate, isostearyl (meth) acrylate, and behenyl (meth) acrylate; Aliphatic, such as isobonyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, and adamantane (meth) acrylate (Meth) acrylates having a ring structure; (Meth) acrylates having aromatic structures such as phenoxyethyl (meth) acrylate and benzyl (meth) acrylate; (Meth) acrylate which has heterocyclic structure, such as tetrahydrofurfuryl (meth) acrylate; Vinyl compounds, such as styrene, hydroxy ethyl vinyl ether, hydroxy butyl vinyl ether, N-vinylformamide, N-vinylpyrrolidone, and N-vinyl caprolactam, are mentioned.

Specific examples of the polyfunctional monomers include 1,4-butanedioldi (meth) acrylate, neopentylglycoldi (meth) acrylate, 1.6-hexanediol (meth) acrylate, and 1,9-nonanedioldi (meth). (Meth) acrylate which has aliphatic structures, such as) acrylate; (Meth) acrylate which has aliphatic ring structure, such as dicyclohexane dimethanol di (meth) acrylate and tricyclodecane di (meth) acrylate; (Meth) acrylate which has aromatic structure, such as bisphenol A ethylene oxide modified di (meth) acrylate and bisphenol F ethylene oxide modified di (meth) acrylate; Trimetholpropane tri (meth) acrylate, isocyanurate ethylene oxide modified tri (meth) acrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate dipentaerythritol pentaacrylate, dipentaerythritol Trifunctional (meth) acrylates, such as hexaacrylate, are mentioned.

Furthermore, the adhesive composition of this invention can contain various additives in the range which does not lose the effect of this invention as needed. For example, it may contain additives such as surface modifiers, surfactants, ultraviolet absorbers, inorganic fillers, silane coupling agents, colloidal silica, antifoaming agents, wetting agents, rust inhibitors, stabilizers, and the like.

In order to make the adhesive composition of this invention into an adhesion layer, it is preferable to employ | adopt the method called a lubricating agent film (cast film forming). Specifically, a release agent such as a silicone resin is coated on the surface, and the adhesive composition is cast in a thin film form on a protective film such as a polyethylene terephthalate film (PET film), and then the coating film is irradiated with ultraviolet rays to polymerize. It hardens and an adhesive layer is obtained. According to such a manufacturing method, there is little stress which an adhesive composition requires at the time of film forming, and there is little formation of a defect. Moreover, the film uniformity of the obtained coating film becomes high.

The ultraviolet light source may be an ultraviolet irradiation device having a xenon lamp, a high pressure mercury lamp, a metal halide lamp, or the like. In addition, what is necessary is just to adjust conditions, such as a light quantity, a light source, and a conveyance speed suitably. The amount of light is usually about 80 ~ 160 W / cm, the conveying speed is usually about 5 ~ 50 m / min.

In addition, the thickness of the adhesion layer of this invention is not specifically limited, Usually, it is about 10-1000 micrometers, Preferably it is about 25-500 micrometers. By setting the film thickness in this range, the impact resistance of the touch panel can be improved, the printing step of the surface can be absorbed, and thus it can be used as the front protective film and is excellent as an adhesive layer.

[ Example ]

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the present invention is not limited to these examples. In addition, in an Example, "part" means a "weight part" unless there is particular notice.

<Synthesis of (A) Component>

Synthesis Example 1

Synthesis of Component (A-1)

955 parts of polypropylene glycol having a weight average molecular weight of 4,000, 34 parts of hexamethylene diisocyanate, and 0.2 parts of octylic acid tin were added to a reaction device equipped with a stirring device and a cooling tube, and the temperature was raised to 80 ° C, and kept warm for 2 hours. After confirming that reaction was completed and a urethane oligomer produced | generated, 2-isocyanate ethyl methacrylate was added in 11 parts and it heated at 80 degreeC for 2 hours. It confirmed that reaction was completed by NCO measurement, and obtained the urethane methacrylate oligomer (henceforth "(A-1) component") of the weight average molecular weight 30,000 and the average functional group 2.0. In addition, the said weight average molecular weight is a commercial molecular weight measuring instrument (body product name "HLC-8220GPC", the product made by Tosoh Co., Ltd .; column product name "TSKGel G1000H", "TSKGel G2000H", Tosoh Co., Ltd.); Value using the developing solvent tetrahydrofuran).

Synthesis Example 2

Synthesis of (A-2) Component

915 parts of polypropylene glycol having a weight average molecular weight of 4,000, 68 parts of isophorone diisocyanate, and 0.8 parts of octylic acid tin were added to a reaction apparatus as in Synthesis Example 1, and the temperature was raised to 80 ° C. 17 parts of was added and kept warm at 80 ° C for 2 hours. It confirmed that reaction was completed by NCO measurement, and obtained the urethane acrylate oligomer (henceforth "(A-2) component") of a weight average molecular weight 25,000 and average functional group 2.0.

<Synthesis of (B) Component>

Synthesis Example 3

Synthesis of Component (B-1)

Acid value 172, softening point (measured by the ring method prescribed in JIS K 5902, the same as below.) 5 parts by weight of palladium containing carbon as a catalyst at 75 ° C. and 1000 parts of gum rosin produced in Hue Gardner 6 Hereafter, 0.3 part of "5% palladium carbon" (50% water content) is added, and under nitrogen sealing, a disproportionation reaction is carried out while stirring at 280 ° C for 4 hours to give an acid value of 157, a softening point of 77 ° C and color tone Gardner 8 Equalized rosin was obtained. The disproportionated rosin was distilled and purified in a vacuum of 3 mmHg under nitrogen sealing, and rosin was obtained by purification of acid value 178, softening point 78 ° C and Hue Gardner 2. 500 parts of this tablet disproportionated rosin was put into a 1 L four-necked flask, heated with nitrogen to 180 ° C, 60 parts of glycerin were added at 200 ° C under melt stirring, and then heated up to 280 ° C, and esterified at this temperature for 12 hours. The acid value 3.4, the softening point 99 degreeC, and Hue Gardner 3 refined disproportionated rosin ester were obtained by doing the following. 200 parts of this purified disproportionated rosin ester and 2 parts of 5% palladium carbon (50% water content) are injected into a 2 L vibrating autoclave to remove oxygen in the system and pressurize the system to 100 kg / cm ² with hydrogen to 255 ° C. It heated up, it hydrogenated at this temperature for 3.5 hours, the hydrogenation rosin ester of the acid value 12.5, softening point 89.5 degreeC, and Hue Gardner 1 or less (adhesive imparting agent (B-1) (hereafter, "(B-1) component" Was obtained).

Synthesis Example 4

Synthesis of (B-2) Component

100 parts of cyclopentadiene, 100 parts of aryl alcohol, and 80 parts of xylene were put into an autoclave, and it was made to react at 270 degreeC for 2 hours in nitrogen atmosphere, and polymerized oil was obtained. The polymerization oil was distilled under reduced pressure at 200 ° C and 2.7 kPa for 15 minutes, and the reaction monomer solvent and the low polymer were still removed. The softening point was 97.5 ° C, Hue Gardner 8, the hydroxyl value was 210 mgKOH / g, and the weight average molecular weight was 540 (polystyrene equivalent of GPC). Chi) hydroxyl group-containing petroleum resin was obtained. 100 parts of this hydroxyl group containing petroleum resin, 100 parts of cyclohexane, and 2.0 parts of stabilized nickel catalysts (made by JGC Corporation, brand name "N-113") are put into an autoclave, and it is 240 degreeC under high pressure hydrogen atmosphere of 18 MPa of hydrogen pressures. The reaction was carried out for 5 hours. After filtering the catalyst, the mixture was distilled under reduced pressure at 220 ° C and 0.27 kPa for 30 minutes to obtain a softening point of 118 ° C, a Hue Gardner 1 or lower, a hydroxyl value of 180 mgKOH / g, and a hydroxyl group-containing petroleum resin having a weight average molecular weight of 600 (polystyrene equivalent of GPC). A hydride (adhesion imparting agent (B-2) (hereinafter, referred to as "(B-2) component") was obtained.

Synthesis Example 5

Synthesis of Component (E-1)

955 parts of polypropylene glycol having a weight average molecular weight of 4,000, 34 parts of hexamethylene diisocyanate and 0.2 parts of octylic acid tin were added to the same reactor as in Synthesis Example 1, and the temperature was raised to 80 ° C. After confirming that a urethane oligomer produced | generated, 6 parts of 2-isocyanate ethyl methacrylates were added and it heated at 80 degreeC for 2 hours. It confirmed that reaction was completed by NCO measurement and obtained the urethane methacrylate oligomer (henceforth "(E-1) component") of the weight average molecular weight 30,000 and the average functional group number 1.0.

Synthesis Example 6

Synthesis of Component (E-2)

955 parts of a polypropylene glycol having a weight average molecular weight of 4,000, 34 parts of hexamethylene diisocyanate and 0.2 parts of octylic acid tin were added to the same reaction apparatus as in Synthesis Example 1, and the temperature was raised to 80 ° C., and after 2 hours of incubation, the reaction was completed by NCO measurement. The urethane oligomer (henceforth "(E-2) component") of the weight average molecular weight 30,000 and the average functional group 0 was obtained.

<Production of Adhesive Composition>

Example 1

3-hydroxypropyl phenyl which is monofunctional epoxy ester acrylate obtained by making phenylglycidyl ether and acrylic acid react with 25 parts of (A-1) components, 5 parts of (B-1) components, and (C) component. 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (TPO) as 45 parts of (A) component of acrylate (HPPA) (made by Koeisha Chemical Co., Ltd., brand name "epoxy ester M-600A") 1 part of BASF Japan Co., Ltd., a brand name "Lucirin TPO", and 25 parts of isostaryl acrylate (ISTA) (manufactured by Osaka Organic Chemical Industry Co., Ltd., ISTA) in a dilution monomer To prepare a pressure-sensitive adhesive composition (Table 1). In addition, all compounding quantities are ratio of solid content. The color tone Gardner color, viscosity, solvent content rate, and compatibility of the obtained composition were evaluated, and the result is shown in Table 2.

Examples 2-5

The adhesive composition was manufactured using the raw material shown in Table 1 about each component at each compounding quantity. Table 2 shows the results of evaluating the color tone Gardner color, viscosity, solvent content and compatibility of each obtained composition.

Comparative Example 1

3-hydride, which is a monofunctional epoxy ester acrylate obtained by reacting phenylglycidyl ether and acrylic acid with 5 parts of (B-1) component and (C) component, without using (A-1) component. 45 parts of oxypropyl phenyl acrylate (HPPA) (made by Koeisha Chemical Co., Ltd., brand name "epoxy ester M-600A") as (D) component, and 2,4,6- trimethylbenzoyl- diphenyl- phosphine 1 part of oxide (TPO) (made by BASF Japan Co., Ltd., brand name "Lucirin TPO"), and isostearyl acrylate (ISTA) (Osaka Organic Chemical Industry Co., Ltd., ISTA) as a dilution monomer. 50 parts were mix | blended and the adhesive composition was prepared. In addition, all compounding quantities are ratio of solid content. The color tone Gardner color, viscosity, solvent content rate, and compatibility of the composition obtained similarly to Example 1 were evaluated, and the result is shown in Table 2.

Comparative Example 2

3-hydride which is a monofunctional epoxy ester acrylate obtained by making phenylglycidyl ether and acrylic acid react with (C) component, without using 25 parts of (A-1) components and (B-1) component. 45 parts of oxypropyl phenyl acrylate (HPPA) (made by Koeisha Chemical Co., Ltd., brand name "epoxy ester M-600A") as (D) component, and 2,4,6- trimethylbenzoyl- diphenyl- phosphine 30 parts of isostaryl acrylate (ISTA) (Osaka Organic Chemical Industries, Ltd., ISTA) are compounded with 1 part of oxide (TPO) (product made from BASF Japan Co., Ltd., brand name "Lucirine TPO"), and a dilution monomer. To prepare an adhesive composition. In addition, all compounding quantities are ratio of solid content. The color tone Gardner color, viscosity, solvent content rate, and compatibility of the composition obtained similarly to Example 1 were evaluated, and the result is shown in Table 2.

Comparative Example 3

2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide as (D) component without using 95 parts of (A-1) components, 5 parts of (B-1) components, and (C) component ( TPO) (BASF Japan Co., Ltd. product, a brand name "Lucirine TPO") was mix | blended, and the adhesive composition was manufactured. In addition, all compounding quantities are ratio of solid content. The color tone Gardner color, viscosity, solvent content rate, and compatibility of the composition obtained similarly to Example 1 were evaluated, and the result is shown in Table 2.

Comparative Example 4

Monofunctional epoxy ester acryl which can be obtained by making phenylglycidyl ether and acrylic acid react with 25 parts of urethane methacrylate oligomers which consist of (A-1) component, 5 parts of (B-1) components, and (C) component. 45 parts of 3-hydroxypropyl phenyl acrylate (HPPA) (the product made by Koeisha Chemical Co., Ltd., a brand name), a brand name "epoxy ester M-600A" is an isoester as a dilution monomer without using (D) component. 25 parts of aryl acrylates (ISTA) (Osaka Organic Chemical Industry Co., Ltd., ISTA) were mix | blended and the adhesive composition was manufactured. In addition, all compounding quantities are ratio of solid content. The color tone Gardner color, viscosity, solvent content rate, and compatibility of the composition obtained similarly to Example 1 were evaluated, and the result is shown in Table 2.

Comparative Example 5

The pressure-sensitive adhesive composition was produced in the same manner as in Example 1 except that the component (B-1) was manufactured and manufactured by Nippon Zeon Co., Ltd., trade name Quintone 1700 (softening point 100 ° C, Hue Gardner 4) (B-3). The color tone Gardner color, viscosity, solvent content rate, and compatibility of the composition obtained similarly to Example 1 were evaluated, and the result is shown in Table 2.

Comparative Example 6

The pressure-sensitive adhesive composition was prepared in the same manner as in Example 1 except that the component (B-1) was replaced by Arakawa Chemical Co., Ltd., and brand name Super Ester A100 (softening point 95 to 105 ° C, Hue Gardner 7) (B-4). The color tone Gardner color, viscosity, solvent content rate, and compatibility of the composition obtained similarly to Example 1 were evaluated, and the result is shown in Table 2.

Comparative Example 7

The pressure-sensitive adhesive composition was prepared in the same manner as in Example 1 except that the component (A-1) was replaced with the component (E-1). The color tone garner color, viscosity, solvent content and compatibility of the composition obtained in the same manner as in Example 1 Was evaluated and the results are shown in Table 2.

Comparative Example 8

The pressure-sensitive adhesive composition was prepared in the same manner as in Example 1, except that the component (A-1) was replaced with the component (E-2). The color tone Gardner color, viscosity, solvent content and compatibility of the composition obtained in the same manner as in Example 1 Was evaluated and the results are shown in Table 2.

TABLE 1

Ista: isostearyl acrylate (ista) (product made in osaka organic chemical industry, trade name "ista")

HPPA: 3-hydroxypropyl phenyl acrylate (HPPA) (product made from Koeisha Chemical Co., Ltd., brand name "epoxy ester M-600A")

L, TPO: 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (TPO) (BASF Japan Co., Ltd. product, a brand name "Lucirine TPO")

TABLE 2

(Tint Gardner Color)

Gardner chromaticity number was measured based on JISK5400.

(Viscosity)

The viscosity (mPa * s) of an adhesive composition was measured on condition of 25 degreeC and 5 minutes with the E-type viscosity meter (Tokisangyo Co., Ltd. TVE-10).

(Solvent content rate)

The solvent content rate of the coating liquid was measured using the gas chromatography apparatus.

<Analysis device>

GC: Agilent, 6850

<GC measurement condition>

GC pillar: HP-1

Column temperature: 50 ° C (10min) → 10 ° C / min → 300 (10min)

Column flow rate: 2.0 ml / min

Carrier gas: Helium

Injection method: Split (50: 1)

Detection temperature: 300 degrees Celsius

(Compatibility)

Compatibility was observed visually on the obtained pressure-sensitive adhesive composition and was judged based on the following criteria.

(Circle): It is uniform and is completely transparent.

X: It is cloudy and completely separated, and there is a bad melt or liquid layer separation is confirmed.

<Production of adhesive layer>

Examples 6-10 and Comparative Examples 9-14

The composition of Example 1 was applied onto a peeling treated polyester film (manufactured by Panac Co., Ltd., trade name "SP-PET-01-38BU") so as to have a film thickness of 150 µm, and the high pressure in air. Precure was carried out by passing once under a mercury lamp (35 mJ / cm ² ). This hardened | cured material coating surface and a 38 micrometer-thick peeling process polyester film were made to adhere | attach so that a peeling process surface may contact, and it hardened | cured by passing it four times under the high pressure mercury lamp (300 mJ / cm <^2> ) in air, and adhere | attached the Example 6 A layer was obtained. The adhesive layers of Examples 7-10 and Comparative Examples 9-14 were similarly produced also about the composition of Examples 2-5 and Comparative Examples 1,2,4,6,7 and 8. The following test is done about each obtained adhesion layer, and the result is shown in Table 3.

[Various tests on adhesive layer]

<Adhesion test>

Peel-processed polyester film was peeled to one side of the adhesion layers of manufactured Examples 6-10 and Comparative Examples 9-14, and 50 micrometer-thick polyester film (made by Orient Spinning Co., Ltd., brand name "Cosmo Shine A- 4300 ") was fitted with a 2 kg roller and left for 2 hours. The remaining peeled polyester film was peeled off and 50 μm PET / adhesive layer (150 μm) / glass specimen was prepared by fitting the glass with a 2 kg roller. After leaving for 24 hours at 25 ° C. and 50% RH, the adhesive force was measured by peeling at a rate of 300 mm / min in the 180 degree direction (N / 25mm).

<Glass rest test>

The glass remainder evaluated whether the adhesive layer remained in glass after measuring the said adhesive force. Evaluation criteria are as follows.

○: The adhesive layer does not remain on the glass

(Triangle | delta): A part of adhesion layer remains on glass

X: An adhesion layer remains on glass

<Measurement of haze value>

A 50 μmPET / adhesive layer (150 μm) / glass specimen was produced in the same manner as the adhesion test for the adhesive layers of Examples 6 to 10 and Comparative Examples 9 to 14, and the haze value was obtained using a color made by Murakami Color Technology Research Institute. It measured using based on JISK5400. In addition, each haze value is a numerical value containing the polyester film which is a base material, and a glass haze value.

<Durability test>

50 μm PET / adhesive layer (150 μm) / glass specimens were prepared for the adhesive layers of Examples 6 to 10 and Comparative Examples 9 to 14 and tested for durability. The endurance test was a moisture resistant heat resistance test stored for 500 hours in a constant temperature and humidity device at 85 ° C-85% relative humidity. After the moisture resistance heat resistance test, the haze value was measured according to JIS K 5400 using a haze meter with a color made by Murakami Color Research Institute. The haze value was measured based on JISK5400 using the haze meter by the color of Murakami Color Technology Research Institute. In addition, each haze value is a numerical value including the polyester film which is a base material, and a glass haze value. The evaluation criteria of durability are as follows.

○: no peeling, no adhesion layer leaching, no whitening of coating

X: There is any one of peeling, adhesion layer leaching, and whitening of a coating film

TABLE 3

Claims (6)

The ultraviolet curable adhesive composition whose solvent content is less than 1 weight%, the viscosity of 25 degreeC is 100-10,000 mPa * s, and a hue is Gardner color 1 or less, and contains following (A)-(D):
(A) a polyfunctional urethane (meth) acrylate oligomer having a weight average molecular weight of 10,000 to 100,000;
(B) tackifier;
(C) monofunctional epoxy ester (meth) acrylate which has a structure with the ring of the epoxy group opened by making glycidyl ether and (meth) acrylic acid react; And
(D) Photoinitiator.
The method of claim 1,
The said (A) component is a ultraviolet curable adhesive composition which is a polyfunctional polyurethane (meth) acrylate oligomer obtained by making polyether polyol, polyisocyanate, and hydroxyl-containing (meth) acrylate or isocyanate-group containing (meth) acrylate react.
The method according to claim 1 or 2,
The said (B) component is a ultraviolet curable adhesive composition whose color tone is a tackifier of Gardner color 1 or less.
The method according to claim 1 or 2,
(A): (B): (C): (D) = 10-60: 0.5-15: 15-89.4: 0.1-10 of said (A)-(D) component by weight part basis in an adhesive composition. UV curable pressure-sensitive adhesive composition blended in proportion.
The adhesive layer obtained by hardening | curing the ultraviolet curable adhesive composition of Claim 1 or 2.
The method of claim 5,
The adhesive layer has a thickness of 10 to 1000 μm.