KR20190026584A - Ultraviolet ray-curable adhesive agent composition for protecting film, adhesive agent layer and protecting sheet - Google Patents

Abstract

The purpose of the present invention is to provide a UV curable adhesive composition for a protection film, an adhesive layer, and a protection sheet. The UV curable adhesive composition for a protection film gives an adhesive layer having excellent adsorption capability and low adhesiveness as a UV curable adhesive composition which is substantially free from a solvent. The UV curable adhesive composition of the present invention comprises: a polyurethane (meth)acrylate (A) that is a reactant of a polyether polyol (a1), a polyisocyanate (a2) and a hydroxyl group-containing mono(meth)acrylate (a3-1) or a reactant of a polyether polyol (a1), a polyisocyanate (a2) and an isocyanate group-containing mono(meth)acrylate (a3-2); an alkylmono(meth)acrylate (B); a hydroxyl group-containing mono(meth)acrylate (C); and a photopolymerization initiator (D). The UV curable adhesive composition contains less than 1 mass% of a solvent, the component (B) comprises an alkylmono(meth)acrylate (B1) containing a branched alkyl group having 8 to 14 carbon atoms and an alkylmono(meth)acrylate (B2) containing a linear alkyl group having 8 to 18 carbon atoms in a solid content mass defined by (B1)/(B2) <= 2, and 0.1 to 1 mass% of the component (D) is contained in the UV curable adhesive composition based on the total amount 100 mass% of the components (A), (B) and (C).

Description

FIELD OF THE INVENTION [0001] The present invention relates to an ultraviolet curing pressure-sensitive adhesive composition for a protective film, a pressure-sensitive adhesive layer,

The present invention relates to an ultraviolet curing pressure-sensitive adhesive composition for a protective film (ultraviolet-curable pressure-sensitive adhesive composition for a protective film), a pressure-sensitive adhesive layer, and a protective sheet.

BACKGROUND ART [0002] In a manufacturing process of optical members and the like, a protective film is temporarily adhered to the surface of a member in order to suppress scratches, dirt, and the like during each process between processing, transportation, and inspection. The protective film is usually peeled off at the end. Recently, the demand for a protective film is increasing, and more particularly, it is demanded to more suitably protect the optical member.

As a protective film for an optical member, even when the protective film is peeled off by any trouble during the process, it can be closely adhered to the member again, and the surface of the optical member is not scratched nor deformed, And it is required that the liquid crystal cell can easily be peeled off so that the alignment of the liquid crystal cell and the cell gap do not occur. Therefore, in the ultraviolet curable pressure-sensitive adhesive composition used for adhering a protective film, it has become important to provide not only self-adsorptivity (self-adsorptivity) but also low adhesiveness (low adhesive strength) upon curing.

Examples of the pressure sensitive adhesive composition as described above include a releasable pressure-sensitive adhesive composition comprising an ethylenically unsaturated group-containing water-affinity acrylic pressure-sensitive adhesive, a photopolymerization initiator, a crosslinking agent and a urethane acrylate oligomer (Patent Document 1) An active energy ray-curable resin composition (Patent Document 2) comprising an ethylenically unsaturated monomer and a photopolymerization initiator in a (meth) acrylate resin is known.

However, in these pressure-sensitive adhesive compositions, when cured, self-adsorptivity and low adhesive strength are not sufficient, and there is room for further improvement.

Japanese Patent Application Laid-Open No. 2001-019911 Japanese Patent Application Laid-Open No. 2004-143233

An object of the present invention is to provide an ultraviolet curing pressure-sensitive adhesive composition for a protective film, a pressure-sensitive adhesive layer and a protective sheet, which give a pressure-sensitive adhesive layer excellent in self-adsorptivity and low adhesive force as a substantially solventless ultraviolet curable pressure- .

As a result of intensive studies, the inventors of the present invention have found that an ultraviolet-curable pressure-sensitive adhesive composition satisfying specific conditions can solve the above-mentioned problems, and completed the present invention. That is, the present invention relates to the following ultraviolet curable pressure-sensitive adhesive composition for a protective film, a pressure-sensitive adhesive layer, and a protective sheet.

1. A method for producing a polyurethane foam, which comprises reacting a reaction product of a polyether polyol (a1), a polyisocyanate (a2) and a hydroxyl group-containing mono (meth) acrylate (a3-1) or a reaction product of a polyether polyol (a1), a polyisocyanate (a2) and an isocyanate group- (Meth) acrylate (A), an alkyl mono (meth) acrylate (B), a hydroxyl group-containing mono (meth) acrylate (C) and a photopolymerization initiator (D), the content of the solvent is less than 1% by mass,

(Meth) acrylate (B1) having a branched alkyl group having 8 to 14 carbon atoms and an alkylmono (meth) acrylate having a straight chain (normal chain) alkyl group having 8 to 18 carbon atoms, (B1) / (B2) &lt; / = 2 in terms of solids mass,

(D) is added in an amount of 0.1 to 1% by mass relative to 100% by mass of the total of the components (A), (B) and (C)

Sensitive adhesive composition for a protective film.

(A) component, (B1) component, (B2) component and (C) component in a total amount of 100 mass% , The component (B2) in an amount of 15 to 84 mass%, and the component (C) in an amount of 1 to 70 mass%.

3. The ultraviolet curable pressure-sensitive adhesive composition for a protective film according to item 1 or 2, wherein the component (a1) has a number average molecular weight of 400 to 4,000.

4. The ultraviolet curable pressure-sensitive adhesive composition for a protective film according to any one of items 1 to 3, wherein the component (a2) is an aliphatic diisocyanate and / or an alicyclic diisocyanate.

5. The UV-curable pressure-sensitive adhesive composition for protective film according to any one of items 1 to 4, wherein the weight-average molecular weight of the component (A) is 5,000 to 70,000.

6. The composition according to any one of items 1 to 5, wherein the component (B1) comprises at least one member selected from the group consisting of 2-ethylhexyl (meth) acrylate, isononyl (meth) acrylate and isodecyl (meth) A UV curable pressure sensitive adhesive composition for one protective film.

7. The composition according to claim 1, wherein component (B2) is selected from the group consisting of n-octyl (meth) acrylate, n-lauryl (meth) acrylate, n-cetyl (meth) The ultraviolet-curing pressure-sensitive adhesive composition for a protective film according to any one of items 1 to 6, which contains at least one species.

8. A pressure-sensitive adhesive layer comprising an ultraviolet-curing pressure-sensitive adhesive composition for a protective film according to any one of items 1 to 7 above.

9. A protective sheet comprising the protective film and the pressure-sensitive adhesive layer of the item 8.

According to the ultraviolet curing pressure-sensitive adhesive composition (hereinafter also referred to as "pressure-sensitive adhesive composition") of the present invention, since the solvent is substantially solvent-free, the step of removing the solvent can be omitted in the production of the pressure-sensitive adhesive sheet. Further, the pressure-sensitive adhesive layer in which the composition is cured has a low adhesive force, and therefore can be easily peeled off from the member when peeling off. (Hereinafter, referred to as self-adsorbing property). Further, when the pressure-sensitive adhesive layer obtained by curing the composition is peeled from the member, the pressure-sensitive adhesive component does not adhere to the member (hereinafter referred to as low migration property), and therefore, the member is also less likely to be contaminated.

The pressure-sensitive adhesive composition of the present invention is suitable as a surface protective sheet for optical members, particularly a surface protective sheet for protecting a photomask. Examples of members other than the photomask include a display (so-called light transmitting member) of an electronic device such as a polarizing plate, a retardation plate, a prism sheet, an anti-reflection film, an anti glare film, and a brightness enhancement film.

The pressure-sensitive adhesive composition of the present invention is a pressure-sensitive adhesive composition comprising a predetermined polyurethane (meth) acrylate (A) (hereinafter referred to as component (A)), alkyl mono (meth) acrylate (B) (Meth) acrylate (hereinafter referred to as component (C)) and a photopolymerization initiator (hereinafter referred to as component (D)).

(A1) (hereinafter referred to as component (a1)), polyisocyanate (component (a2) (hereinafter referred to as component (a2)), and polyisocyanate (A3-1) (hereinafter referred to as a component (a3-1)) or a reaction product of a component (a1), a component (a2) and an isocyanate group-containing mono (meth) acrylate ) (Hereinafter referred to as component (a3-2)).

The component (a1) is not particularly limited and various known compounds can be used. For example, polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. These may be used alone or in combination of two or more. As commercial products, for example, adeka polyether polyol 1000, adeka polyether polyol 2000 (manufactured by ADEKA), PTMG 650, PTMG 1000, PTMG 2000 (manufactured by Mitsubishi Chemical Corporation) . Among these, polypropylene glycol is preferable from the viewpoints of the self-adsorption property and the low adhesive force of the pressure-sensitive adhesive layer.

The physical properties of the component (a1) are not particularly limited. For example, a number average molecular weight (polystyrene conversion value by gel permeation chromatography, hereinafter the same) To about 10,000, preferably about 1,000 to about 4,000. The average number of hydroxyl groups (average number of hydroxyl groups) present in one molecule is not particularly limited, but is usually about 1.5 to 3, preferably about 2 to 3, from the viewpoint of low adhesive strength of the pressure-sensitive adhesive layer.

The component (a2) is not particularly limited and various known compounds can be used. Aromatic diisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate and xylylene diisocyanate; Aliphatic diisocyanates such as hexamethylene diisocyanate, trimethylhexamethylene diisocyanate and lysine diisocyanate; (Alicyclic) diisocyanates such as dicyclohexylmethane diisocyanate, isophorone diisocyanate, 1,4-cyclohexane diisocyanate, hydrogenated xylene diisocyanate and hydrogenated tolylene diisocyanate. Or two or more of them may be used in combination. Among these, aliphatic diisocyanate and / or alicyclic diisocyanate are preferable from the viewpoint of low adhesive strength of the pressure-sensitive adhesive layer.

The component (a3-1) is not particularly limited and various known ones can be used. (Meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (Meth) acrylate, and 6-hydroxyhexyl acrylate. These mono (meth) acrylates may be used alone or in combination of two or more. Of these, mono (meth) acrylates having a total of 5 to 10 carbon atoms are preferred from the viewpoints of the self-adsorbing property and low adhesive force of the pressure-sensitive adhesive layer, and 2-hydroxyethyl (meth) acrylate and 4- Butyl (meth) acrylate is more preferable.

The component (a3-2) is not particularly limited and various known ones can be used. (Meth) acrylate such as 2-isocyanatoethyl (meth) acrylate, 1,1-bis (acryloyloxymethyl) ethyl isocyanate, 2- These may be used alone or in combination of two or more.

The component (A) is not particularly limited and is produced by various known methods. (A2) obtained by using the component (A1) (hereinafter referred to as component (A1)) obtained by using the component (a3-1) as the component (a3) and the component (a3-2) (Hereinafter referred to as component (A2)).

The component (A1) is not particularly limited, and for example, an isocyanate group-terminated urethane prepolymer (hereinafter referred to as component (A1 ')) is prepared by reacting the component (a1) (A3-1). The reaction conditions are not particularly limited and usually the temperature is about 70 to 85 DEG C and the time is about 1 to 5 hours. ), but the proportion of the component is not limited, non-(NCO _(a2 with) and (a1) can mol of hydroxyl group of component (OH _(a1)), (a2) an isocyanate group mol number (NCO _(a2 of the component _{a) )} / OH _(a1) ) is usually in the range of about 1.01 to 2. The ratio of the components (A1 ') and (a3-1) used is not particularly limited, but the molar number of the isocyanate groups the _{NCO (A1 ') (/ OH} (a3-1))) to the number of mol of the latter hydroxyl group (OH _(a3-1) a non-NCO _(A1) with) "usually 0.25 to 1 tablet If the good range.

(A2 ') is obtained by reacting the component (a1) and the component (a2) to obtain a hydroxyl-terminated urethane prepolymer (hereinafter referred to as component (A2' The ratio of the component (a1) to the component (a2) is not particularly limited, but the ratio of (NCO _(a2) / OH _(a1) ) to The ratio of the component (A2 ') to the component (a3-2) is not particularly limited, but the molar number of the latter isocyanate group (NCO _(a3-2) ) and It may be a _{non-(NCO (a3-2)} / OH _(A2 with ₍₎₎₎ number of mol of hydroxyl group of the e-OH _(A2), is usually the range of about 0.5 to 1.

These components (A1) and (A2) may be produced in the absence of a solvent or in the presence of a component (B) described later.

As the component (A), the components (A1) and (A2) may be used in combination.

The average number of (meth) acryloyl groups of the component (A) is usually from about 1.5 to about 4, preferably from about 1.8 to about 2.2, from the viewpoint of low adhesive strength and low migration performance of the pressure-sensitive adhesive layer. The average number of (meth) acryloyl groups in the component (A) means the average number of (meth) acryloyl groups present in one molecule of the component (A).

The physical properties of the component (A) are not particularly limited, but the weight average molecular weight is preferably about 5,000 to 70,000, and more preferably about 10,000 to 50,000, from the viewpoint of the self-adsorbing property and low adhesive strength of the pressure-sensitive adhesive layer. The Gardner color scale is not particularly limited, but is preferably 1 or less.

The content of the component (A) is not particularly limited, and the content of the component (A) is preferably from 15 to 84% by mass, the total content of the component (A) to be. When the component (A) is in this range, the low adhesive strength and the low planarity of the pressure-sensitive adhesive layer tend to be excellent. From the same viewpoint, it is preferably 20 to 84 mass%, more preferably 30 to 84 mass%.

(B1) (hereinafter referred to as component (B1)) having a branched (branched) alkyl group having 8 to 14 carbon atoms and a linear chain having a carbon number of 8 to 18 (linear: normal (B1) / (B2)? 2 in terms of the solid content of the alkyl mono (meth) acrylate (B2) (hereinafter referred to as component (B2)). When alicyclic (alicyclic) (meth) acrylates such as cyclohexyl (meth) acrylate and isobornyl (meth) acrylate are used as the component (B), the self-adsorbing property of the pressure- Further, since the adhesive force becomes high and it becomes difficult to peel off the member, it is not preferable.

(B1) is a component that imparts flexibility because of its low glass transition temperature. When this component is used, the final pressure-sensitive adhesive layer has excellent self-adsorbability. Examples of the component (B1) include, but are not limited to, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, isodecyl (meth) (Meth) acrylate, isododecyl (meth) acrylate, isomyristyl (meth) acrylate and the like. These may be used alone or in combination of two or more. Among them, from the viewpoint of self-adsorption property of the pressure-sensitive adhesive layer, it is preferable to include at least one kind selected from the group consisting of 2-ethylhexyl (meth) acrylate, isononyl (meth) acrylate and isodecyl , And 2-ethylhexyl acrylate and isodecyl acrylate are more preferable.

The content of the component (B1) is 0 to 69% by mass when the total content of the component (A), the component (B) and the component (C) is 100 mass%. When the component (B1) is in the above range, the self-adsorbing property of the pressure-sensitive adhesive layer tends to be improved. From the same viewpoint, it is preferably 10 to 50 mass%, more preferably 10 to 40 mass%.

The component (B2) is a component that contributes to the self-adsorbing property and the low adhesive force of the pressure-sensitive adhesive layer. The component (B2) is not particularly limited, and examples thereof include n-octyl (meth) acrylate, n-nonyl (meth) acrylate, n-decyl (meth) (meth) acrylate, n-lauryl (meth) acrylate, myristyl (meth) acrylate, n-cetyl . These may be used alone or in combination of two or more. Among them, from the viewpoint of the low adhesive force of the pressure-sensitive adhesive layer, it is preferable to use a pressure-sensitive adhesive layer made of n-octyl (meth) acrylate, n-lauryl (meth) acrylate, n-cetyl (meth) , And more preferably at least one selected from the group consisting of n-lauryl acrylate, n-cetyl acrylate and n-stearyl acrylate.

The content ratio of the component (B2) is not particularly limited, but it is usually from 15 to 84 mass% when the total amount of the component (A), the component (B1), the component (B2) and the component (C) is 100 mass% . When the component (B2) is in the above range, the low adhesive strength of the pressure-sensitive adhesive layer tends to be excellent. From the same viewpoint, it is preferably 15 to 75 mass%, and more preferably 20 to 65 mass%.

The content ratio of the component (B1) and the component (B2) is (B1) / (B2)? If the ratio is more than 2, the adhesive force of the pressure-sensitive adhesive layer becomes high and it becomes difficult to peel off the member.

The component (C) is not particularly limited and various known ones can be used. (Meth) acrylate, 4-hydroxybutyl (meth) acrylate, cyclohexanedimethanol mono (meth) acrylate, and the like. These may be used alone or in combination of two or more May be used in combination. Of these, 4-hydroxybutyl (meth) acrylate is preferable from the viewpoint of the self-adsorbing property and the low migration property of the pressure-sensitive adhesive layer.

The content of the component (C) is 1 to 70% by mass based on 100% by mass of the total of the components (A), (B) and (C). (C) falls within this range, the low-migration property of the pressure-sensitive adhesive layer tends to be excellent. From the same viewpoint, it is preferably 1 to 50 mass%, more preferably 5 to 30 mass%.

The component (D) is not particularly limited and various known ones can be used. Examples thereof include photopolymerization initiators such as benzoin compounds, acetophenone compounds, acylphosphine oxide compounds, titanocene compounds, thioxanthone compounds and oxime ester compounds, and photosensitizers such as amines and quinones. More specifically, there can be mentioned 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxycyclohexyl phenyl ketone, 2- Methyl-1-propan-1-one, 2-hydroxy-1- [4- [4- ( Methyl-1- (4-methylthiophenyl) -2-morpholinopropane-1-one, 2-methyl- Methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone, 2,4,6-trimethyl benzoyl diphenyl phosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenyl phosphine oxide, bis (η ⁵ -2,4- cyclopentadiene-1-yl) -bis (2,6-di-fluoro (Phenylthio) -2- (o-benzoyloxime)], ethanone 1- [9 (trifluoromethyl) (O-acetyloxime), and these may be used alone or in combination of two or more kinds The. Of these, 1-hydroxycyclohexyl phenyl ketone is preferable from the viewpoint of low adhesive strength and low migration property of the pressure-sensitive adhesive layer.

The content of the component (D) is 0.1 to 1 mass% with respect to 100 mass% of the total of the components (A), (B) and (C). When the content is less than 0.1% by mass, the pressure-sensitive adhesive composition is hardly cured by ultraviolet rays, and when it exceeds 1% by mass, the pressure-sensitive adhesive layer increases in adhesive strength and becomes difficult to peel off from the member. From the same viewpoint, it is preferably 0.2 to 0.5 mass%.

Various known polymerizable polyfunctional monomers may be added to the pressure-sensitive adhesive composition of the present invention as necessary. (Meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, (poly) ethylene glycol di (Meth) acrylate, urethane (meth) acrylate, urethane (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (Meth) acrylate. These may be used alone, or two or more of them may be used in combination. The amount to be used is not particularly limited, and is usually about 20% by mass or less based on 100 parts by mass of the pressure-sensitive adhesive composition of the present invention.

The pressure-sensitive adhesive composition of the present invention may contain various known additives as necessary. For example, a surface modifier, a surfactant, an ultraviolet absorber, an antioxidant, a light stabilizer, an inorganic filler, a silane coupling agent, a colloidal silica, a defoaming agent, a wetting agent and an antirust agent may be used. Or may be used in combination.

The pressure-sensitive adhesive composition of the present invention is obtained by mixing the components (A), (B), (C) and (D) and, if necessary, the additives. The mixing means and the mixing order are not particularly limited. When the component (A) is diluted with the component (B), the components (C) and (D) and, if necessary, the above additives may be mixed into the solution of the component (B) of the component (A).

The pressure-sensitive adhesive composition of the present invention is substantially solvent-free, and the content of the solvent is less than 1% by mass, preferably less than 0.1% by mass. Examples of the solvent include aromatic solvents such as benzene, toluene, ethylbenzene, n-propylbenzene, t-butylbenzene, o-xylene, m-xylene, p-xylene, tetralin, decalin and aromatic naphtha hydrocarbon; aliphatic hydrocarbons such as n-hexane, n-heptane, n-octane, i-octane and n-decane; Alicyclic hydrocarbons such as cyclohexane; Esters such as ethyl acetate, n-butyl acetate, n-amyl acetate, 2-hydroxyethyl acetate, 2-butoxyethyl acetate, 3-methoxybutyl acetate and methyl benzoate; Ketones such as acetone, methyl ethyl ketone, methyl-i-butyl ketone, isophorone, cyclohexanone and methylcyclohexanone; Glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether and diethylene glycol monobutyl ether; Examples thereof include alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, i-propyl alcohol, n-butyl alcohol, i-butyl alcohol, s-butyl alcohol and t-butyl alcohol.

The pressure-sensitive adhesive layer of the present invention is obtained by curing the pressure-sensitive adhesive composition.

The pressure-sensitive adhesive layer of the present invention is not particularly limited, and is obtained by applying the pressure-sensitive adhesive composition to a member and irradiating ultraviolet rays.

Examples of the member include, but are not limited to, polyethylene terephthalate film (PET film), cycloolefin polymer (COP film), polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, Vinyl acetate copolymer film, polyethylene naphthalate film, polybutylene terephthalate film, polyurethane film, ethylene vinyl acetate film, ionomer resin film, ethylene (meth) acrylic acid copolymer film, ethylene (meth) A co-extruded film, a polystyrene film, a polycarbonate film, a polyimide film, a fluororesin film and the like. A crosslinked film or a laminated film thereof may also be used. These films may be subjected to a light to heavy stripping treatment or may be provided with this adhesive layer (easy adhesion layer).

The application method is not particularly limited, and examples thereof include an applicator, a bar coater, a roll coater, a die coater, a comma coater, a knife coater, and a gravure coater.

The ultraviolet light source is not particularly limited, and examples thereof include a xenon lamp, a high-pressure mercury lamp, and a metal halide lamp. In addition, the amount of light and the conveying speed of ultraviolet rays are not particularly limited, but usually the light quantity is 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 and is usually about 1 to 500 m, preferably about 1 to 200 m, from the viewpoint of low adhesive strength.

The protective sheet of the present invention comprises a protective film and the pressure-sensitive adhesive layer of the present invention. The method of the member, application and curing is as described above.

[Example]

Hereinafter, the present invention will be described in detail with reference to examples and comparative examples. It goes without saying that the technical scope of the present invention is not limited by these. In the examples, &quot; part &quot; and &quot;% &quot; are on a mass basis unless otherwise specified.

Production Example 1

884 parts of polypropylene glycol having a number average molecular weight of 2000 (trade name: ADEKA POLYERTER P-2000, available from ADEKA Co., Ltd.) (hereinafter referred to as PPG2000) 106 parts of phthalic anhydride (hereinafter, IPDI), 250 parts of n-lauryl acrylate (hereinafter referred to as LA) and 0.4 part of stannous octylate were added, and the mixture was heated to 80 DEG C and kept at this temperature for 3 hours. To obtain an LA solution of a urethane prepolymer. Subsequently, 10 parts of 4-hydroxybutyl acrylate (hereinafter referred to as 4HBA) was added and the mixture was kept at 80 DEG C for 2 hours. By confirming the completion of the reaction by NCO measurement, the weight average molecular weight was 52,000 and the average number of acryloyl groups was 2 To obtain an LA solution of polyurethane acrylate (A-1) (hereinafter referred to as component (A-1)).

Production Example 2

1228 parts of PPG2000, 122 parts of dicyclohexylmethane diisocyanate (hereinafter, referred to as hydrogenated MDI), 250 parts of 2-ethylhexyl acrylate (hereinafter, 2-EHA) and 1 part of stannous octylate , And the mixture was heated to 80 DEG C and kept at this temperature for 3 hours, to obtain a 2-EHA solution of an isocyanate-terminated urethane prepolymer as an intermediate. Subsequently, 10 parts of 4HBA was added and the mixture was kept at 80 占 폚 for 2 hours. By confirming the completion of the reaction by NCO measurement, a polyurethane acrylate (A-2) having a weight average molecular weight of 56,000 and an average number of acryloyl groups of 2 , (A-2)) was obtained.

Production Example 3

856 parts of PPG2000, 119 parts of IPDI and 0.5 part of stannous octylate were added to the same reaction apparatus as in Production Example 1, and the mixture was heated to 80 占 폚 and kept warm for 3 hours to obtain an isocyanate-terminated urethane prepolymer as an intermediate. Subsequently, 25 parts of 2-hydroxyethyl acrylate (hereinafter referred to as HEA) was added and the mixture was kept at 80 DEG C for 2 hours. By confirming the completion of the reaction by NCO measurement, the weight average molecular weight was 25,000 and the average number of acryloyl groups was 2 Polyurethane acrylate (A-3) (hereinafter referred to as component (A-3)).

Comparative Preparation Example 1

(Trade name: Kuraray Polyol C-2090, manufactured by Kuraray Co., Ltd.) having a number average molecular weight of 2000 (hereinafter referred to as &quot; C-2090), 92 parts of hydrogenated MDI, 250 parts of 2-EHA and 0.5 parts of stannous octylate were added. After the temperature was raised to 80 DEG C and the mixture was maintained at the temperature for 3 hours, 2-EHA of an isocyanate-terminated urethane prepolymer Solution. Subsequently, 6 parts of HEA was added and the mixture was kept at 80 占 폚 for 2 hours. By confirming completion of the reaction by NCO measurement, a polyurethane acrylate (E-1) having a weight average molecular weight of 60,000 and an average number of acryloyl groups of 2 , And component (E-1)).

Comparative Production Example 2

652 parts of a polyester polyol having a number average molecular weight of 2000 (product of Daicel Corporation, trade name "PLACCEL L220AL"), 92 parts of hydrogenated MDI, 2-EHA And 0.5 part of stannous octylate were added. After the temperature was raised to 80 ° C and the temperature was maintained for 3 hours, a 2-EHA solution of an isocyanate-terminated urethane prepolymer as an intermediate was obtained. Subsequently, 6 parts of HEA was added and the mixture was maintained at 80 占 폚 for 2 hours. By confirming the completion of the reaction by NCO measurement, a polyurethane acrylate (E-2) having a weight average molecular weight of 63,000 and an average number of acryloyl groups of 2 , (E-2)) was obtained.

Example 1

(Hereinafter referred to as &quot; Luna 200 &quot;, trade name &quot; Luna 200 &quot;, manufactured by DKSH Japan) as the component (A-1), 2-EHA as the component (B1), 4HBA as the component (C), 1-hydroxycyclohexyl phenyl ketone ) Were mixed in a content ratio shown in Table 1 to obtain an ultraviolet curable pressure-sensitive adhesive composition for protective film.

Examples 2 to 13 and Comparative Examples 1 to 10

The ultraviolet curable pressure sensitive adhesive composition for a protective film was obtained in the same manner as in Example 1 with the composition shown in Table 1.

The abbreviations of the components in Table 1 mean the following compounds.

&Lt; Component (A) >

A-1: Polyurethane acrylate of Production Example 1

A-2: Polyurethane acrylate of Production Example 2

A-3: Polyurethane acrylate of Production Example 3

E-1: Polyurethane acrylate of Comparative Production Example 1

E-2: Polyurethane acrylate of Comparative Production Example 2

&Lt; Component (B1) >

2-EHA: 2-ethylhexyl acrylate (having 8 carbon atoms)

IDAA: isodecyl acrylate (having a carbon number of 10)

ISTA: isostearyl acrylate (having a carbon number of 18)

&Lt; Component (B2) >

BA: n-butyl acrylate (having 4 carbon atoms)

NOAA: n-octyl acrylate (having 8 carbon atoms)

LA: n-lauryl acrylate (having a carbon number of 12)

CA: n-cetyl acrylate (having 16 carbon atoms)

SA: n-stearyl acrylate (having a carbon number of 18)

VA: Behenyl acrylate (having 22 carbon atoms)

&Lt; Component (C) >

4HBA: 4-hydroxybutyl acrylate

&Lt; Component (D) >

L200: 1-Hydroxycyclohexyl phenyl ketone

(Trade name: "Luna200", product of DKSH Japan Ltd.)

&Lt; Component (F) >

IBXA: isobornyl acrylate

The following tests were carried out on the ultraviolet curable pressure-sensitive adhesive composition for a protective film of each of the examples and the comparative examples.

Evaluation Examples 1 to 13, Comparative Evaluation Examples 1 to 9

The pressure-sensitive adhesive composition of Example 1 was coated on a polyester film (trade name: COSMOSHINE A-4100, product of TOYOBO CO., LTD.) (Hereinafter referred to as A4100) The coated surface was coated with a comma coater so as to have a thickness of 10 mu m and a 38 mu m thick light-peeled polyester film (product of PANAC CO., LTD., Product name: SP-PET- (Manufactured by IWASAKI ELECTRIC CO., LTD.) Of 120 W / cm was used to form a laminate film having a thickness of 38 mu m Light-exfoliation treatment A protective sheet composed of a polyester film / pressure-sensitive adhesive layer (10 m) / A4100 was prepared by irradiating ultraviolet light of 900 mJ / cm ² from the polyester film side. Protective sheets of Examples 2 to 13 and Comparative Examples 1 to 7 and 9 to 10 were also prepared in the same manner.

1. Adhesion

A laminate (A4100 / pressure-sensitive adhesive layer / glass) was prepared by peeling the light-cured polyester film of the protective sheet and bonding it to a glass plate with a 2 kg roller, and left standing for 24 hours under conditions of a temperature of 25 DEG C and a humidity of 50%. Subsequently, the laminate was peeled from the glass plate in the direction of 180 DEG at a rate of 300 mm / min using a commercially available tester (product of A & D Company, Limited, Tensilon universal material tester) to obtain an adhesive strength (mN / 25 mm) . The smaller the value, the better the low adhesion. The results are shown in Table 2 (hereinafter the same).

2. Evaluation of adhesion (self-adsorption) to members

A measurement sample of 50 mm x 50 mm was cut out from the protective sheet. The lightly polished polyester film was peeled off from the measurement sample in an atmosphere at a temperature of 23 DEG C and a humidity of 50% and then the both ends of the sheet were grasped with both hands, and the center of the exposed surface of the pressure- Was brought into contact with the glass plate, and both hands were removed. The time until the entirety of the pressure-sensitive adhesive layer adhered to the glass plate was measured by the own weight of the sheet, and the self-adsorbability to the glass plate was evaluated based on the following criteria. The shorter the time until the glass plate is brought into close contact with the glass plate, the easier it is to adhere to the member (the self-adsorption property is excellent).

(Evaluation standard)

○: less than 3 seconds (good)

?: 3 seconds or more, less than 5 seconds (practicable)

×: more than 5 seconds (practically impossible)

3. Transparency

A laminated product (A-4100 / pressure-sensitive adhesive layer / glass plate) was prepared by peeling off the lightly polished polyester film from the protective sheet and bonding the surface of the pressure-sensitive adhesive layer to the glass plate with 2 kg roller, And left for 24 hours. The haze value of the laminate and the haze value after standing for 500 hours in a constant temperature and humidity bath at a temperature of 85 DEG C and a humidity of 85% were measured using a color haze meter (Murakami Color Research Laboratory) K 5400, respectively. The obtained haze value is a value including the haze value of the member (material A-4100 and glass plate).

4. Durability of pressure-sensitive adhesive layer

After durability of the pressure-sensitive adhesive layer was evaluated according to the following criteria after the laminate was allowed to stand for 500 hours in a constant-temperature and constant humidity chamber at a temperature of 85 캜 and a humidity of 85%.

○: peeling of the member, displacement of the pressure-sensitive adhesive layer position, bubble in the pressure-sensitive adhesive layer, and breakage of the pressure-sensitive adhesive layer

X: At least one defect such as peeling of the member, displacement of the pressure-sensitive adhesive layer, bubbles in the pressure-sensitive adhesive layer, and breakage of the pressure-sensitive adhesive layer occurred

5. Transparency of the pressure-sensitive adhesive layer

The state of the residue of the paste on the surface of the glass plate after the measurement of the adhesive strength of item 1 was visually confirmed to evaluate the migration property of the pressure-sensitive adhesive layer. The evaluation criteria are as follows.

○: There is no residual pool

DELTA: Partially there is a slightly full residue

X: There is a full residue on the entire surface of the glass plate

Evaluation Examples 14 to 16, Comparative Evaluation Examples 10 to 12

The thickness of the pressure-sensitive adhesive layer was changed to 100 mu m using the ultraviolet curable pressure-sensitive adhesive compositions of Examples 8 to 10 and Comparative Examples 3, 4 and 8 to obtain a light-peeled polyester film / pressure-sensitive adhesive layer / A4100 Were prepared and evaluated in the same manner. The results are shown in Table 3.

Claims (9)

A reaction product of a polyether polyol (a1), a polyisocyanate (a2) and a hydroxyl group-containing mono (meth) acrylate (a3-1) or a reaction product of a polyether polyol (a1), a polyisocyanate (a2) and an isocyanate group- (Meth) acrylate (A), which is a reactant of the acrylate (a3-2)
Alkyl mono (meth) acrylate (B)
(C) containing a hydroxyl group-containing mono (meth) acrylate,
Photopolymerization initiator (D)
Lt; / RTI &gt;
The content of the solvent is less than 1% by mass,
(Meth) acrylate (B1) having a branched alkyl group having 8 to 14 carbon atoms and an alkylmono (meth) acrylate (B2) having a straight-chain alkyl group having 8 to 18 carbon atoms, (B1) / (B2) &lt; / = 2 as the solid mass,
(D) is added in an amount of 0.1 to 1% by mass relative to 100% by mass of the total of the components (A), (B) and (C)
Sensitive adhesive composition for a protective film.
The method according to claim 1,
Wherein the content of the component (A) is from 15 to 84 mass%, the content of the component (B1) is from 0 to 69 mass%, the content of the component (B1) 15 to 84% by mass of the component (B2) and 1 to 70% by mass of the component (C).
3. The method according to claim 1 or 2,
and the number average molecular weight of the component (a1) is 400 to 4000. The ultraviolet curable pressure-
The method according to any one of claims 1 to 3,
wherein the component (a2) is an aliphatic diisocyanate and / or an alicyclic diisocyanate.
The method according to any one of claims 1 to 4,
(A) has a weight average molecular weight of 5,000 to 70,000.
6. The method according to any one of claims 1 to 5,
Wherein the component (B1) comprises at least one member selected from the group consisting of 2-ethylhexyl (meth) acrylate, isononyl (meth) acrylate and isodecyl (meth) acrylate.
7. The method according to any one of claims 1 to 6,
(B2) is at least one member selected from the group consisting of n-octyl (meth) acrylate, n-lauryl (meth) acrylate, n-cetyl (meth) Sensitive adhesive composition for a protective film.
A pressure-sensitive adhesive layer comprising an ultraviolet-curing pressure-sensitive adhesive composition for a protective film according to any one of claims 1 to 7.
A protective sheet comprising a protective film and the pressure-sensitive adhesive layer of claim 8.