KR20150005552A - 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 a solvent-free agent that can be used for a touch panel, a plasma display panel, and the like, and an adhesive layer of a thick film can be formed by a single coating. Further, the pressure-sensitive adhesive composition of the present invention is excellent in durability under the conditions of transparency, adhesive force, heating and humidification, and further, can be peeled off without leaving glue. (A) a polyfunctional urethane (meth) acrylate having a solvent content of less than 1% by weight, a viscosity at 25 ° C of from 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 (C) a monofunctional epoxy ester (meth) acrylate, and (D) a photopolymerization initiator. The present invention relates to an ultraviolet curable pressure-sensitive adhesive composition,

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an ultraviolet curable pressure-

The present invention relates to a UV-curable pressure-sensitive adhesive composition and an adhesive layer.

2. Description of the Related Art In recent years, display devices such as a vehicle-mounted device, an outdoor device, a display device such as a PC, and a TV have been required to be lightweight or flat. In recent years, particularly, digital information devices such as ATMs, vending machines, mobile phones, portable information terminals, digital audio players, portable game machines, electronic dictionaries, copiers, facsimiles and car navigation systems of financial institutions such as banks are equipped with liquid crystal display The touch panel used is widely used.

The touch panel is an electronic component that combines a display device and a position input device. The touch panel displays image information received from the outside on a liquid crystal display, and senses the contacted screen position information and outputs the information as an information signal to the outside. The position input device of the touch panel mainly includes a resistance film type, a capacitance type, an electromagnetic induction type, an optical type, and an acoustic type. In particular, a resistance film type and a capacitance type are general control methods.

The resistive film type and capacitive type touch panel may include a film having a transparent conductive layer such as a top protective film, glass and indium oxide (hereinafter referred to as "ITO") film, a display device such as glass or liquid crystal, Sheet. Of these, films, glass, and functional sheets are usually stuck together by an optical adhesive.

As described above, the optical pressure-sensitive adhesive for use as a touch panel may be applied to a frontmost protective film or a film or glass having a glass and a transparent conductive layer, or a film having a transparent conductive layer or a glass or a liquid- Optical properties such as transparency and weather resistance are required.

As such an optical pressure-sensitive adhesive, there has been proposed an optical pressure-sensitive adhesive composition for optical use produced from various high molecular weight acrylic polymers and various crosslinking agents (see Patent Documents 1 and 2).

On the other hand, in recent years, a thick adhesive layer having a thickness of 100 占 퐉 or more is required for improving the impact resistance of the touch panel, absorbing the frontmost protective film or the printed step of the glass. An adhesive layer of such a thick film (having a thickness of 100 占 퐉 or more) can be obtained by forming an adhesive layer having a thickness of 25 占 퐉 or 50 占 퐉 from the above-mentioned optical pressure-sensitive adhesive composition and superposing them. However, this method has a problem in that the number of steps is high, which is costly, and transparency is lowered due to alignment. On the other hand, if an adhesive layer having a thickness of 100 占 퐉 or more is formed with a single coating, there is a problem that the performance as an optical property can not be satisfied because foam is generated when the coating solvent is dried and bubbles are generated in the coating film.

As a method of obtaining a pressure-sensitive adhesive layer having a thickness of 100 占 퐉 or more with a single coating without foaming, use of a pressure-sensitive adhesive composition without a solvent form has been considered. A UV-curable, solventless pressure-sensitive adhesive composition comprising various (meth) acrylate oligomers or (meth) acrylate monomers as a solventless pressure-sensitive adhesive structure has been proposed (see Patent Document 3).

However, the pressure-sensitive adhesive composition of the present invention is problematic in terms of transparency, adhesive strength, durability under heating and humidifying conditions, and in the case where a positional difference is caused when sticking, a paste is left in the case of peeling.

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

The present invention relates to a pressure-sensitive adhesive composition for optical use of a solventless adhesive for use in a touch panel or the like, which can form a pressure-sensitive adhesive layer of a thick film by a single coating and has excellent durability under the conditions of transparency, adhesive strength, heating and humidifying conditions, Sensitive adhesive composition which can be peeled off without leaving the ultraviolet curable pressure-sensitive adhesive composition.

The present inventors have intensively studied and found that the ultraviolet curable pressure-sensitive adhesive structure has a solvent content of less than 1% by weight, a viscosity at 25 ° C of 100 to 10,000 mPa · s and a color tone of Gardner color 1 or less, (B) a tackifier, (C) a monofunctional epoxy ester (meth) acrylate oligomer having a number average molecular weight of from 10,000 to 100,000, a number average molecular weight (in terms of polystyrene of Gel Permeation Chromatography, Acrylate, and (D) a photopolymerization initiator.

Further, the inventors of the present invention have found that it is possible to provide a pressure-sensitive adhesive layer which can solve the above problems by using the pressure-sensitive adhesive composition.

That is, the present invention relates to the following ultraviolet-setting type pressure-sensitive adhesive composition and pressure-sensitive adhesive layer.

1. An ultraviolet-curable pressure-sensitive adhesive composition, which comprises a solvent content of less than 1% by weight, a viscosity at 25 占 폚 of 100 to 10,000 mPa 占 퐏, a color tone of Gardner color 1 or less, and 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) a tackifier;

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

(D) a photopolymerization initiator.

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

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

4. The pressure-sensitive adhesive composition according to any one of claims 1 to 3, wherein the components (A) to (D) are (A) :( B) :( C) :( D) 10 to 60: 0.5 to 15: 15 to 89.4: 0.1 to 10, based on the total weight of the ultraviolet curing pressure-sensitive adhesive composition.

5. An adhesive layer obtained by curing the ultraviolet-curable pressure-sensitive adhesive composition according to any one of claims 1 to 4.

6. The adhesive layer according to claim 5, wherein the thickness of the adhesive layer is 10 to 1000 mu m.

The pressure-sensitive adhesive composition of the present invention does not require drying of the solvent due to a solvent-free agent that can be used for a touch panel, a plasma display panel, and the like, and an adhesive layer of a thick film can be formed by a single coating. Further, the pressure-sensitive adhesive composition of the present invention is excellent in durability under the conditions of transparency, adhesive strength, heating and humidification, and can be peeled off without leaving a paste after being stuck. Accordingly, the pressure-sensitive adhesive layer of the present invention formed from the pressure-sensitive adhesive composition is excellent in tackiness, transparency and durability thereof, and is preferable as an adhesive layer for use in touch panels, plasma display panels and the like.

(A) a polyfunctional urethane (meth) acrylate having a solvent content of less than 1% by weight, a viscosity at 25 ° C of 100 to 10,000 mPa · s, a color tone of Gardner color 1 or less and (A) a weight average molecular weight of 10,000 to 100,000 (Hereinafter referred to as "component (B)"), (C) a monofunctional epoxy ester (meth) acrylate (hereinafter referred to as " C) component ") and (D) a photopolymerization initiator (hereinafter referred to as" component (D) ").

When the content of the solvent is 1 wt% or more, there is a problem that when a thick film (thickness of 100 μm or more) is to be formed as an adhesive layer, the coating solvent is foamed when dried and cured, and bubbles are formed in the coated film.

When the viscosity is out of the range of 100 to 10,000 mPa.s, it becomes difficult to form a thick adhesive layer at one time in a room temperature and atmospheric pressure.

By setting the color tone of the pressure-sensitive adhesive composition to 1 or less in Gardner's color, an adhesive layer excellent in transparency and color tone can be formed.

When the weight average molecular weight of the component (A) is 10,000 or more, the adhesive strength of the adhesive layer can be improved. By setting the weight average molecular weight of the component (A) to 100,000 or less, the viscosity of the polyfunctional urethane (meth) acrylate oligomer can be lowered, and handling of the pressure sensitive adhesive is improved.

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

The polyol is not particularly limited, and examples thereof include polyether polyols such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol and copolymers thereof; Polyester polyols such as polycondensation product of adipic acid and polyhydric alcohol, polycondensation product of sebacic acid and polyhydric alcohol, polycondensation product of phthalic acid and polyhydric alcohol, and addition product obtained by ring-opening reaction between lactones and polyhydric alcohol; Polycarbonate polyols obtained by reacting a diol such as 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol or cyclohexanedimethanol with phosgene; And polyolefin polyols such as polybutadiene diol and hydrogenated polybutadiene polyol. These may be used singly or in combination. Particularly, the use of a polyether polyol is preferable from the viewpoint of low viscosity of the pressure-sensitive adhesive and high adhesive strength of the pressure-sensitive adhesive layer.

The polyisocyanate may be at least one selected from the group consisting of 2,4-trilene diisocyanate, 2,6-trilene diisocyanate, 1,3-xylene diisocyanate, diphenylmethane-4,4-diisocyanate, 3- Aromatic diisocyanate compounds such as 1,5-naphthalene diisocyanate; Alicyclic diisocyanate compounds such as dicyclohexylmethane diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate; And their 2- to 6-mer compounds. These may be used singly or in combination. Particularly, the use of an aliphatic diisocyanate is preferable from the viewpoint of low viscosity of the pressure-sensitive adhesive, high adhesive strength of the pressure-sensitive adhesive layer and durability.

Containing urethane prepolymer obtained by reacting the polyol with a polyisocyanate is reacted with a hydroxyl group-containing (meth) acrylate or by reacting the polyol with a polyisocyanate. To the urethane prepolymer containing a terminal hydroxyl group, an isocyanate group-containing (meth) (Meth) acrylate oligomer can be obtained by reacting a polyfunctional urethane (meth) acrylate oligomer.

The hydroxyl group-containing (meth) acrylate may be at least one selected from the group consisting of 2-hydroxy (meth) acrylate, hydroxypropyl (meth) acrylate, Monofunctional (meth) acrylate such as acrylate; Polyfunctional (meth) acrylates such as pentaerythritol triacrylate and dipentaerythritol pentaacrylate; And epoxy ester (meth) acrylates obtained by reacting an epoxy compound with (meth) acrylic acid. These may be used singly or in combination.

Examples of the isocyanate group-containing (meth) acrylate include 2-isocyanate ethyl (meth) acrylate and 1,1- (bisacryloyloxymethyl) ethyl isocyanate. These may be used singly or in combination.

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 number of functional groups of the urethane (meth) acrylate oligomer is a number that indicates how many average acryloyl groups are present in one urethane (meth) acrylate oligomer molecule. (Meth) acrylate oligomer is controlled by controlling the reaction amount of the hydroxyl group-containing (meth) acrylate compound or the isocyanate group-containing (meth) acrylate compound in the synthesis of the urethane (meth) can do. By using a urethane (meth) acrylate oligomer having an average number of functional groups of 1.5 or more, an optical pressure-sensitive adhesive excellent in durability can be obtained.

The component (B) is a tackifier. Specific examples of the component (B) include petroleum resin phenol resin, xylene resin, coumarone resin, rosin resin, terpene resin, hydrogenated petroleum resin, hydrogenated rosin resin, hydrogenated terpene resin and the like. Among them, it is usually preferable that the color tone is 1 or less of the Gardner color. Examples of the color having a Gardner color of 1 or less include a hydrogenated petroleum resin and a hydrogenated rosin-based resin. These hydrogenated resins generally have a Gardner color of not more than 1 and thus improve the transparency of the pressure-sensitive adhesive for optical use and the pressure-sensitive adhesive layer which are excellent in transparency. In addition, these hydrogenated resins exhibit less polymerization inhibition in the case of polymerization by ultraviolet irradiation, and therefore, they can be used for optical adhesives excellent in curability.

The hydrogenated rosin-based resin is not particularly limited as long as the rosin-based resin is hydrogenated, and known ones can be used. Examples of the rosin-based resin include natural rosins such as gum rosin, tall oil rosin, and wood rosin, and natural rosins in addition to polymerization, denaturation, Rosin metal salts obtained by reacting rosin (hereinafter referred to as "processed rosin"), natural rosin or processed rosin with metals such as calcium, magnesium and zinc, which are processed by at least one kind of method selected from reaction and esterification And the like.

A method for producing a rosin (hereinafter also referred to as " polymerized rosin ") processed by the polymerization method in the above-described processed rosin is not particularly limited and a known method may be employed. For example, there is a method of heating a rosin prepared by the above-mentioned natural rosin or natural rosin with at least one method selected from denaturation, disproportionation and esterification using a polymerization catalyst. The polymerization catalyst is not particularly limited and known catalysts 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.

A method for producing a rosin (hereinafter also referred to as " modified rosin ") processed by the above-mentioned denaturation method is not particularly limited and a known method may be employed. Usually, a method in which a mixture of a natural rosin and a phenol or an unsaturated fatty acid is heated is used. The phenol is not particularly limited and specific examples thereof include phenol, alkyl phenol and the like. The unsaturated fatty acid is not particularly limited, and specific examples thereof include fumaric acid, maleic acid (meth) acrylic acid, and the like.

A method for producing the rosin (hereinafter also referred to as "disproportionated rosin") processed by the disproportionation method is not particularly limited and a known method may be employed. In general, natural rosin or processed rosin is saponified by reacting at 220 to 250 ° C for 2 to 6 hours in the presence of a reducing catalyst such as nickel, silver, palladium or the like without adding hydrogen.

The method for producing the rosin (hereinafter also referred to as "rosin ester") processed by the esterification method is not particularly limited and a known method can be employed. Usually, there is a method of mixing a natural rosin or a processed rosin with an alcohol and, if necessary, heating in the presence of an esterification catalyst. Examples of the esterification catalyst include acid catalysts such as acetic acid and para-toluenesulfonic acid, 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 may be used.

The alcohols include aliphatic monovalent or polyvalent alcohols having 1 to 20 carbon atoms. Examples of such alcohols include alcohols such as methanol, ethanol, isopropyl alcohol, isoamyl alcohol, n-hexyl alcohol, 2-ethylhexyl alcohol, n-octyl alcohol, dodecyl alcohol, lauryl alcohol, stearyl alcohol, Monohydric alcohols such as ethyl alcohol; Dihydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol and neopentyl glycol; Trihydric alcohols such as glycerin, trimethylol ethane and trimethylol propane; And tetravalent alcohols such as pentaerythritol and diglycerin.

These rosin-based resins may be used singly or in combination of two or more kinds. In addition, natural rosins and the like can be processed using two or more methods of polymerization, denaturation, disproportionation and esterification. When a rosin-based resin is produced through two or more methods, the order of the method is not particularly limited, and it may be a known method. For example, the natural rosin or the processed rosin may be polymerized after the modification, or the polymer may be esterified.

Is not particularly limited as long as the petroleum resin is hydrogenated with the hydrogenated petroleum resin as the component (B), and known ones can be used. Examples of the petroleum resin include an aliphatic petroleum resin, an aromatic petroleum resin and a dicyclopentadiene petroleum resin depending on the type of raw material monomer (oil). Examples of the aliphatic petroleum resin include a C5 petroleum resin and a C5-C9 petroleum resin. Examples of the aromatic petroleum resin include C9 petroleum resin. The C5-based petroleum resin can be obtained by cationic polymerization of C5-based petroleum oil (for example, pentene, methylbutene, isoprene, cyclopentene, etc.). The C9-based petroleum resin is not particularly limited, but C9-based petroleum oil (for example, styrene, vinyltoluene,? -Methylstyrene, indene and the like) obtained through cracking of naphtha is generally subjected to cationic polymerization Can be used. The C5-C9 petroleum resin is obtained by copolymerizing the C5-based petroleum fraction and the C9-based petroleum fraction in the same manner as the C5-based petroleum resin. The dicyclopentadiene-based petroleum resin is obtained by subjecting dicyclopentadiene to thermal polymerization or cationic polymerization. These petroleum resins may be modified by a known method such as a hydroxyl group or an ester group in a polar group. The color tone of the petroleum resin is usually about 5 to 15 Gardner.

The component (C) may be any of known various monofunctional epoxy ester (meth) acrylates which can be obtained by reacting a monofunctional epoxy compound with (meth) acrylic acid. (Meth) acrylate, (methylphenyl) phenylglycidyl ether and (meth) acrylic acid which can be obtained by reacting phenylglycidyl ether with (meth) acrylic acid, (Meth) acrylate, which can be obtained by reacting a monofunctional epoxy ester (meth) acrylate, (t-butylphenyl) phenylglycidyl ether and (meth) acrylic acid, (Meth) acrylate having a carbon number of 1 to 30 such as a monofunctional epoxy ester (meth) acrylate obtainable by reacting (ethylhexyl) glycidyl ether methyl (meth) acrylate with (Meth) acrylate. Among them, monofunctional epoxy ester (meth) acrylate having an aromatic structure is preferable from the viewpoint of compatibility of urethane (meth) acrylate oligomer and tackifier.

Any known photopolymerization initiator may be used without particular limitation as long as the component (D) generates a radical decomposed by ultraviolet irradiation. As the component (D), a photopolymerization initiator such as a benzoin compound, an acetophenone compound, an acylphosphine oxide compound, a titanocene compound, a thioxene compound or an oxime ester compound; Amines, and quinones, and the like. Specific examples of the compound include 2,2-dimethoxy-1,2-diphenylethane-1-one, 1 -hydroxy-cyclohexyl-phenyl-ketone, 2- 2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1- [4- [4- (2-hydroxy- Methyl-1- (4-methylthiophenyl) -2-morpholinopropane-1-one, 1-one, 2- (dimethylamino) -2 - [(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl] Bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, bis (? 5-2,4-cyclopentadien-1-yl) -bis (2,6- (Phenylthio) -2- (O-benzoyloxime)], ethanone 1 [2- (4-fluorophenyl) 9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl] -1- (0-acetyloxime). These may be used singly or in combination of two or more kinds. Of these, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide and bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide are preferable because the curing property of the pressure-sensitive adhesive composition is improved.

The components (A) to (D) are contained in the pressure-sensitive adhesive composition in an amount of from 10 to 60: 0.5 to 15: 15 to 89.4: 0.1 to 10 (B) Ratio. A particularly preferable mixing ratio is 20 to 35: 5 to 10:30 to 70: 0.2 to 5. When the blending ratio of the component (A) is in the above range, the adhesive strength of the adhesive layer can be improved, and at the same time, the handling of the adhesive can be improved. When the compounding ratio of the component (B) is within the above range, the adhesive strength of the adhesive layer can be improved and the rest of the adhesive layer can be removed. When the compounding ratio of the component (C) is in the above range, handling of the pressure-sensitive adhesive can be improved, a suitable viscosity can be obtained at the same time, and the thick film adhesive layer can be formed with a single coating. By setting the compounding ratio of the component (D) within the above range, it is possible to prevent the deviation of the polymerization caused by irradiation with active energy rays such as ultraviolet rays, and to prevent odor from decomposition products of the component (D) Can be prevented.

The ultraviolet curable pressure sensitive adhesive composition of the present invention can be prepared by mixing the above components (A) to (D). The mixing method is not particularly limited, and the order of addition of the above components (A) to (D) is not relevant.

In the pressure-sensitive adhesive composition of the present invention, various monofunctional or polyfunctional monomers may be contained as dilution monomers insofar as the effect of the present invention is not impaired.

Specific examples of the monofunctional monomer include monofunctional monomers such as methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, (Meth) acrylate, n-pentyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (Meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, isooctyl (meth) acrylate, (Meth) acrylate having an alkyl group of 1 to 30 carbon atoms such as isopropyl (meth) acrylate, isostearyl (meth) acrylate and behenyl (meth) acrylate; Aliphatic (meth) acrylates such as isobornyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyloxyethyl (Meth) acrylates having a cyclic structure; (Meth) acrylate having an aromatic structure such as phenoxyethyl (meth) acrylate and benzyl (meth) acrylate; (Meth) acrylate having a heterocyclic structure such as tetrahydrofurfuryl (meth) acrylate; Vinyl compounds such as styrene, hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, N-vinyl formamide, N-vinyl pyrrolidone and N-vinyl caprolactam.

Specific examples of the polyfunctional monomer include 1,4-butanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,6-hexanediol (meth) acrylate, 1,9- (Meth) acrylate having an aliphatic structure such as acrylate; (Meth) acrylate having an aliphatic cyclic structure such as dicyclohexanedimethanol di (meth) acrylate and tricyclodecanediyl (meth) acrylate; (Meth) acrylates having an aromatic structure such as bisphenol A ethylene oxide modified di (meth) acrylate and bisphenol F ethylene oxide modified di (meth) acrylate; (Meth) acrylate, trimethylolpropane tri (meth) acrylate, isocyanuric acid ethylene oxide modified tri (meth) acrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate dipentaerythol pentaacrylate, dipentaerythritol And trifunctional (meth) acrylates such as hexaacrylate.

Furthermore, the pressure-sensitive adhesive composition of the present invention may contain various additives insofar as the effects of the present invention are not impaired, if necessary. For example, additives such as a surface conditioner, a surfactant, an ultraviolet absorber, an inorganic filler, a silane coupling agent, a colloidal silica, a defoaming agent, a humectant, an antirust agent, and a stabilizer may be contained.

In order to form the adhesive layer of the pressure-sensitive adhesive composition of the present invention, it is preferable to adopt a technique called a flow-regulating film (cast film forming). Specifically, a releasing agent such as a silicone resin is coated on the surface to cast a pressure-sensitive adhesive composition on a protective film such as a polyethylene terephthalate film (PET film) in the form of a thin film, And an adhesive layer is obtained by curing. According to this production method, the stress required for the pressure-sensitive adhesive composition at the time of film formation is small and the formation of defects is small. In addition, the uniformity of the obtained film is improved.

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. Further, the conditions such as the light amount, the light source, and the conveying speed may be appropriately adjusted. The amount of light is usually about 80 to 160 W / cm, and the conveying speed is usually about 5 to 50 m / min.

The thickness of the pressure-sensitive adhesive layer of the present invention is not particularly limited, but is usually about 10 to 1000 μm, and preferably about 25 to 500 μm. By setting the film thickness in this range, it is possible to improve the impact resistance of the touch panel and to absorb the printed steps of the surface, so that it can be used as a frontmost 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 embodiments. In the examples, " parts " means " parts by weight " unless otherwise specified.

≪ Synthesis of component (A) >

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 part of tin octylate were placed in a reactor equipped with a stirrer and a cooling tube, and the temperature was raised to 80 DEG C and maintained at that temperature for 2 hours. After confirming that the reaction was completed to form a urethane oligomer, 11 parts of 2-isocyanatoethyl methacrylate was added and the mixture was kept at 80 ° C for 2 hours. It was confirmed that the reaction was completed in the NCO measurement, and a urethane methacrylate oligomer having a weight average molecular weight of 30,000 and an average number of functional groups of 2.0 (hereinafter referred to as "(A-1) component") was obtained. The weight average molecular weight was measured by using a commercially available molecular weight analyzer (product name: "HLC-8220GPC", manufactured by Tosoh Corporation; columns "TSKGel G1000H", "TSKGel G2000H", manufactured by Tosoh Corporation; Developing solvent tetrahydrofuran) (hereinafter the same).

Synthesis Example 2

(A-2) Synthesis of components

915 parts of polypropylene glycol having a weight average molecular weight of 4,000, 68 parts of isophorone diisocyanate and 0.8 part of tin octylate were placed in a reactor similar to that of Synthesis Example 1, and the temperature was raised to 80 DEG C and maintained at that temperature for 2 hours. 2-Hydroxyethyl acrylate , And the mixture was kept at 80 캜 for 2 hours. (Hereinafter referred to as " component (A-2) ") having a weight average molecular weight of 25,000 and an average number of functional groups of 2.0 was obtained by confirming that the reaction was completed in the NCO measurement.

≪ Synthesis of Component (B) >

Synthesis Example 3

Synthesis of Component (B-1)

An acid value of 172, a softening point (measured by a ring method as specified in JIS K 5902, the same shall apply hereinafter), and 75 parts by weight of carbon containing 5 wt% of palladium as a catalyst in 1000 parts of Gum rosin, 0.3 part of water content (hereinafter referred to as " 5% palladium carbon ") (water content 50%) was added and disproportionation was carried out with stirring at 280 캜 for 4 hours under nitrogen sealing to obtain an acid value of 157, a softening point of 77 캜, A homogenized rosin was obtained. The disproportionated rosin was subjected to distillation purification in a vacuum of 3 mmHg under nitrogen sealing, and rosin was obtained by purification of an acid value of 178, a softening point of 78 캜 and a color tone Gardner 2. 500 parts of the refined disproportionated rosin was placed in a 1 L four-necked flask and heated to 180 DEG C under nitrogen sealing. 60 parts of glycerin was added at 200 DEG C under melting and stirring, and then the temperature was raised to 280 DEG C and esterification reaction To obtain a disproportionated rosin ester having an acid value of 3.4, a softening point of 99 占 폚 and three tablets of Gardner Gardner. It was poured into a purified disproportionated rosin ester, 200 parts, and 5% palladium oscillating autoclave carbon (water content 50%) 2 parts of 2L, to remove the oxygen in the system under pressure to 100 kg / cm ² of a system with hydrogen 255 ℃ (B-1) (hereinafter, referred to as " component (B-1) ") having an acid value of 12.5, a softening point of 89.5 DEG C and a color tone Gardner of 1 or less was subjected to a hydrogenation reaction at this temperature for 3.5 hours ).

Synthesis Example 4

Synthesis of Component (B-2)

100 parts of cyclopentadiene, 100 parts of aryl alcohol and 80 parts of xylene were put into an autoclave and reacted at 270 DEG C for 2 hours under a nitrogen atmosphere to obtain polymerized oil. The polymerized oil was distilled under reduced pressure at 200 DEG C and 2.7 kPa for 15 minutes to remove the reaction monomer solvent and low polymerizate to obtain a copolymer having a softening point of 97.5 DEG C, a color tone of 8, a hydroxyl value of 210 mgKOH / g and a weight average molecular weight of 540 Containing hydroxyl group-containing petroleum resin. 100 parts of this hydroxyl group-containing petroleum resin, 100 parts of cyclohexane and 2.0 parts of a stabilized nickel catalyst (trade name "N-113", manufactured by JGC Corporation) were put in an autoclave and heated at 240 ° C. For 5 hours. The catalyst was filtered and then distilled under reduced pressure at 220 캜 and 0.27 kPa for 30 minutes to obtain a hydroxyl group-containing petroleum resin having a softening point of 118 캜, a color tone of 1 or less, a hydroxyl value of 180 mgKOH / g and a weight average molecular weight of 600 (GPC in terms of polystyrene) (B-2) (hereinafter referred to as " component (B-2) ").

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 part of tin octylate were placed in the same reaction apparatus as in Synthesis Example 1, and the temperature was raised to 80 DEG C and maintained at that temperature for 2 hours. After confirming that the urethane oligomer was produced, 6 parts of 2-isocyanate ethyl methacrylate was added and the mixture was kept at 80 ° C for 2 hours. (Hereinafter referred to as " component (E-1) ") having a weight average molecular weight of 30,000 and an average number of functional groups of 1.0 was obtained by confirming that the reaction was completed in the NCO measurement.

Synthesis Example 6

Synthesis of Component (E-2)

955 parts of polypropylene glycol having a weight average molecular weight of 4,000, 34 parts of hexamethylene diisocyanate and 0.2 part of tin octylate were added to the same reactor as in Synthesis Example 1, and the temperature was raised to 80 DEG C and maintained at that temperature for 2 hours. (Hereinafter referred to as " component (E-2) ") having a weight average molecular weight of 30,000 and an average number of functional groups of 0 was obtained.

≪ Preparation of pressure-sensitive adhesive composition >

Example 1

Which is a monofunctional epoxy ester acrylate obtained by reacting 25 parts of the component (A-1), 5 parts of the component (B-1), and phenylglycidyl ether and acrylic acid as the component (C) 45 parts of acrylate (HPPA) (trade name: "Epoxyester M-600A", manufactured by Koeisha Chemical Co., Ltd.), 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide ), 25 parts of isostearyl acrylate (ISTA) (ISTA, manufactured by Osaka Organic Chemical Industry Co., Ltd.) as a diluting monomer, 1 part of a polyvinyl butyral resin (BASF Japan Ltd., trade name "Lucirin TPO" To prepare a pressure-sensitive adhesive composition (Table 1). In addition, the blending amount is all the ratio of the solid content. The color tone of the obtained composition, Gardner color, viscosity, solvent content and compatibility were evaluated, and the results are shown in Table 2.

Examples 2 to 5

A pressure-sensitive adhesive composition was prepared using the ingredients shown in Table 1 for each component in the respective blending amounts. Table 2 shows the results of evaluation of color tone Gardner color, viscosity, solvent content and compatibility of each of the obtained compositions.

Comparative Example 1

Which is a monofunctional epoxy ester acrylate obtained by reacting 5 parts of the component (B-1) and acrylic acid with phenylglycidyl ether as the component (C) without using the component (A-1) 45 parts of epoxypropyl phenyl acrylate (HPPA) (trade name " Epoxy ester M-600A ", manufactured by Koeisha Chemical Co., Ltd.), 2,4,6-trimethylbenzoyl-diphenyl-phosphine (ISTA) (ISTA, manufactured by Osaka Organic Chemical Industry Co., Ltd.) as a diluting monomer, and 1 part of an isoparaffin oxide (TPO) (trade name "Lucirin TPO" To obtain a pressure-sensitive adhesive composition. In addition, the blending amount is all the ratio of the solid content. The color tone of the composition obtained in the same manner as in Example 1, Gardner color, viscosity, solvent content and compatibility were evaluated. The results are shown in Table 2.

Comparative Example 2

Which is a monofunctional epoxy ester acrylate which is obtained by reacting 25 parts of the component (A-1), the component (B-1), and the component (C), with phenylglycidyl ether and acrylic acid, 45 parts of epoxypropyl phenyl acrylate (HPPA) (trade name " Epoxy ester M-600A ", manufactured by Koeisha Chemical Co., Ltd.), 2,4,6-trimethylbenzoyl-diphenyl-phosphine (ISTA) (ISTA, manufactured by Osaka Organic Chemical Industry Co., Ltd.) was diluted with 1 part of an aqueous solution of sodium hydroxide (TPO) (trade name "Lucirin TPO" To prepare a pressure-sensitive adhesive composition. In addition, the blending amount is all the ratio of the solid content. The color tone of the composition obtained in the same manner as in Example 1, Gardner color, viscosity, solvent content and compatibility were evaluated. The results are shown in Table 2.

Comparative Example 3

(Trimethylbenzoyl-diphenyl-phosphine oxide (B)) was used as the component (D) without using the component (C) TPO) (manufactured by BASF Japan Ltd., trade name " Lucirin TPO ") was blended to prepare a pressure-sensitive adhesive composition. In addition, the blending amount is all the ratio of the solid content. The color tone of the composition obtained in the same manner as in Example 1, Gardner color, viscosity, solvent content and compatibility were evaluated. The results are shown in Table 2.

Comparative Example 4

25 parts of the urethane methacrylate oligomer composed of the component (A-1), 5 parts of the component (B-1), and 5 parts of the monofunctional epoxy ester acrylic (meth) acrylate obtained by reacting phenylglycidyl ether and acrylic acid as the component 45 parts of 3-hydroxypropyl phenyl acrylate (HPPA) (trade name "Epoxy ester M-600A", manufactured by Koeisha Chemical Co., Ltd.) 25 parts of aryl acrylate (ISTA) (manufactured by Osaka Organic Chemical Industry Co., Ltd., ISTA) was blended to prepare a pressure-sensitive adhesive composition. In addition, the blending amount is all the ratio of the solid content. The color tone of the composition obtained in the same manner as in Example 1, Gardner color, viscosity, solvent content and compatibility were evaluated. The results are shown in Table 2.

Comparative Example 5

A pressure-sensitive adhesive composition was prepared in the same manner as in Example 1 except that the component (B-1) was changed to Quintone 1700 (softening point 100 캜, color tone Gardner 4) (B-3) The color tone of the composition obtained in the same manner as in Example 1, Gardner color, viscosity, solvent content and compatibility were evaluated. The results are shown in Table 2.

Comparative Example 6

A 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., Trade name Superester A100 (softening point 95 to 105 캜, color tone Gardner 7) (B-4) The color tone of the composition obtained in the same manner as in Example 1, Gardner color, viscosity, solvent content and compatibility were evaluated. The results are shown in Table 2.

Comparative Example 7

A 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 of the composition obtained in the same manner as in Example 1, Gardner color, And the results are shown in Table 2.

Comparative Example 8

A pressure-sensitive adhesive composition was prepared in the same manner as in Example 1 except that the component (A-1) was replaced by the component (E-2). The color tone of the composition obtained in the same manner as in Example 1, Gardner color, And the results are shown in Table 2.

[Table 1]

ISTA: Isostearyl acrylate (ISTA) (trade name " ISTA ", manufactured by Osaka Organic Chemical Industry Co., Ltd.)

HPPA: 3-hydroxypropyl phenyl acrylate (HPPA) (trade name " Epoxy ester M-600A ", manufactured by Koeisha Chemical Co., Ltd.)

L, TPO: 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (TPO) (trade name "Lucirin TPO"

[Table 2]

(Color tone Gardner color)

The Gardner chromaticity number was measured in accordance with JIS K5400.

(Viscosity)

The viscosity (mPa · s) of the pressure-sensitive adhesive composition was measured by an E-type viscometer (TVE-10, manufactured by Toki Sangyo Co., Ltd.) at 25 ° C for 5 minutes.

(Content of solvent)

The solvent content of the coating solution was measured using a gas chromatograph.

<Analyzer>

GC: Agilent, 6850

&Lt; GC measurement condition >

GC Column: HP-1

Column temperature: 50 캜 (10 min)? 10 캜 / min? 300 (10 min)

Column flow rate: 2.0 ml / min

Carrier gas: Helium

Injection method: Split (50: 1)

Detection temperature: 300 ° C

(Compatibility)

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

?: Uniform, completely transparent.

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

<Preparation of Adhesive Layer>

Examples 6 to 10 and Comparative Examples 9 to 14

The composition of Example 1 was coated on a release-treated polyester film (trade name: "SP-PET-01-38BU", manufactured by Panac Co., Ltd.) having a thickness of 38 μm so as to have a film thickness of 150 μm, (35 mJ / cm &lt; ² &gt;). The adhesive of Example 6 and cured by the cured product passing of coated surface and Higo 38μm held according to the peeling-treated surface of the peeling treatment the polyester film having a thickness of the ground, air, and 4 under a high pressure mercury lamp (300 mJ / cm ²⁾ Layer. The pressure-sensitive adhesive layers of Examples 7 to 10 and Comparative Examples 9 to 14 were similarly prepared for the compositions of Examples 2 to 5 and Comparative Examples 1, 2, 4, 6, 7 and 8. The following tests were carried out for each adhesive layer thus obtained, and the results are shown in Table 3.

[Various Tests for Adhesive Layer]

<Adhesion Test>

A peel-off polyester film was peeled from one side of each of the pressure-sensitive adhesive layers of Examples 6 to 10 and Comparative Examples 9 to 14, and a polyester film having a thickness of 50 탆 (trade name: Cosmo Shine A- 4300 &quot;) was fitted with a 2 kg roller and allowed to stand for 2 hours. The remaining exfoliated polyester film was peeled off and the glass was fitted with a 2 kg roller to prepare a 50 μm PET / adhesive layer (150 μm) / glass specimen. After standing for 24 hours at 25 占 폚 and 50% RH, peeling was carried out at a rate of 300 mm / min in the direction of 180 占 (N / 25 mm).

&Lt; Glass rest test >

The rest of the glass was evaluated for the presence of an adhesive layer on the glass after the adhesive strength was measured. The evaluation criteria are as follows.

○: No adhesive layer remains on the glass

DELTA: Part of the adhesive layer remained on the glass

X: Adhesive layer remains on the glass

&Lt; Measurement of Haze Value >

A 50 占 mPET / adhesive layer (150 占 퐉) / glass specimen was prepared for the adhesive layers of Examples 6 to 10 and Comparative Examples 9 to 14 in the same manner as in the adhesive strength test, and the haze value was measured by a haze meter And measured according to JIS K5400. In addition, each haze value is a value including a polyester film as a base and a haze value.

<Durability Test>

The adhesive layers of Examples 6 to 10 and Comparative Examples 9 to 14 were subjected to a durability test with a 50 μm PET / adhesive layer (150 μm) / glass specimen similarly to the adhesive strength test. The durability test was carried out by a humid heat resistance test in which the sample was stored for 500 hours in a constant-temperature and constant-humidity device having a temperature of 85 ° C and a relative humidity of 85%. After the humid heat resistance test, the haze value was measured in accordance with JIS K 5400 using a haze meter manufactured by Murakami Color Research Laboratory. The haze value was measured in accordance with JIS K 5400 using a haze meter in the color of Murakami Color Research Laboratory. Each haze value is a value including the polyester film and the haze value of the base material. The evaluation criteria for durability are as follows.

○: No peeling, no leaching of adhesive layer, no whitening of film

X: either peeling, leaching of the adhesive layer, or whitening of the coating film

[Table 3]

Claims (6)

Wherein the solvent content is less than 1% by weight, the viscosity at 25 占 폚 is 100 to 10,000 mPa 占 퐏, the color tone is Gardner color 1 or less, and 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) a tackifier;
(C) monofunctional epoxy ester (meth) acrylate; And
(D) a photopolymerization initiator.
The method according to claim 1,
The component (A) is a polyfunctional urethane (meth) acrylate oligomer obtained by reacting a polyether polyol, a polyisocyanate and a hydroxyl group-containing (meth) acrylate or an isocyanate group-containing (meth) acrylate.
3. The method according to claim 1 or 2,
The component (B) is a UV-curable pressure-sensitive adhesive composition wherein the color tone is a tackifier having a Gardner color of 1 or less.
4. The method according to any one of claims 1 to 3,
(A): (B): (C): (D) = 10 to 60: 0.5 to 15:15 to 89.4: 0.1 to 10, based on the weight of the pressure- By weight of the ultraviolet curing pressure-sensitive adhesive composition.
An adhesive layer obtained by curing the ultraviolet-curable pressure-sensitive adhesive composition according to any one of claims 1 to 4.
6. The method of claim 5,
Wherein the pressure-sensitive adhesive layer has a thickness of 10 to 1000 占 퐉.