KR20160068667A - Surface protection film - Google Patents

Abstract

The present invention provides a surface protection film that exhibits excellent wettability and cushioning properties and thus can adhere successfully even to a surface having a large step height. Also, the present invention provides an optical member and an electrical member, to which such surface protection films are adhered to. The surface protection film of the present invention includes an adhesive layer, wherein the adhesive layer is mainly composed of a polyurethane-based adhesive that contains a polyurethane-based resin, and shows an adhesion rate of 80% or more when attached with only its own weight to a surface having an arithmetical average illuminance, Ra, of 0.2-2 μm.

Description

Surface Protective Film {SURFACE PROTECTION FILM}

The present invention relates to a surface protective film. The surface protective film of the present invention is a surface protective film comprising a pressure sensitive adhesive layer as an outermost layer, and the pressure sensitive adhesive layer contains a urethane pressure sensitive adhesive containing a polyurethane resin as a main component. The surface protective film of the present invention is preferably used for protecting the surface of an optical member or an electronic member, for example.

Generally, the surface protective film is adhered to the exposed surface side of the optical member or the electron member in order to prevent the surface of the optical member or the electronic member from being scratched during processing, assembling, inspection, and transportation. Such a surface protective film is peeled off from the optical member or the electron member at the time when the need for surface protection is eliminated.

Such a surface protective film has been used in many cases in which the same surface protective film is continuously used until the final shipment through the manufacturing process of the optical member or the electron member, the assembling process, the inspection process, the transportation process, and the like. In this case, in many cases, such a surface protective film is adhered, peeled, and re-bonded by manual operation in each step.

When the surface protective film is adhered by hand or when a surface protective film is adhered to a large adherend, air bubbles may be curled between the adherend and the surface protective film. There have thus been reported several techniques for improving the wettability of the surface protective film so that the bubbles are not curled at the time of bonding. For example, a surface protective film using a silicone resin having a high wetting speed as a pressure-sensitive adhesive layer is known (see, for example, Patent Document 1).

However, when a silicone resin is used for the pressure-sensitive adhesive layer, the pressure-sensitive adhesive component tends to contaminate the adherend, so that it is difficult to use it as a surface protective film for protecting the surface of members such as optical members and electronic members, .

BACKGROUND ART [0002] A surface protective film using an acrylic resin as a pressure-sensitive adhesive layer is known as a surface protective film having little contamination derived from a pressure-sensitive adhesive component (see, for example, Patent Document 2). However, the surface protective film using an acrylic resin as a pressure-sensitive adhesive layer is poor in wettability, and therefore, when the surface protective film is adhered by hand, air bubbles may be curled between the adherend and the surface protective film. In addition, when an acrylic resin is used for the pressure-sensitive adhesive layer, there is a problem that a pressure-sensitive adhesive residue is likely to be generated at the time of peeling, and thus it is difficult to use as a surface protective film for protecting the surface of members such as optical members and electronic members there is a problem.

In addition, when the surface protective film is adhered to an adherend, it is required to have excellent wettability such as the initial wettability as described above, and at the same time, light fastness is required. This is to prevent the adherend from being damaged at the time of peeling, to be re-adhered to the adherend after peeling, and to be used again as a surface protective film. If the peeling is heavy even though the wettability is good, in the case of a thin and fragile adherend, the surface protective film is deformed when the adherend is broken or the surface protective film is peeled off, so that the surface protective film can not be used again as the surface protective film. In order to avoid such a problem, the surface protective film used for the optical member and the electron member is strongly adhered to the surface of the base material, which can be adhered several times without curling the base material, Is required.

In order to solve such a problem, a surface protective film having a pressure-sensitive adhesive layer containing a specific urethane pressure-sensitive adhesive has recently been reported (see, for example, Patent Documents 3 and 4).

However, the conventional surface protective film having a pressure-sensitive adhesive layer containing a urethane-based pressure-sensitive adhesive has a problem in that it can not attain a sufficiently high adhesion rate because the step-followability is poor when bonded to an adherend having a large surface step difference.

Japanese Patent Application Laid-Open No. 2006-152266 Japanese Patent Laid-Open No. 2004-051825 Japanese Patent Application Laid-Open No. 2014-111701 Japanese Patent Application Laid-Open No. 2004-111702

It is an object of the present invention to provide a surface protective film which can achieve a sufficiently high adhesion rate because it has excellent wettability and excellent step traceability even when adhered to an adherend having a large surface step difference. Another object of the present invention is to provide an optical member and an electronic member to which such a surface protective film is adhered.

In the surface protective film of the present invention,

A surface protective film comprising a pressure-sensitive adhesive layer,

The pressure-sensitive adhesive layer contains a urethane pressure-sensitive adhesive containing a polyurethane resin as a main component,

The adherence rate when the adhesive layer side is bonded only to the surface of the adherend having a center line average roughness Ra of 0.2 to 2 탆 only by its own weight is 80% or more.

In a preferred embodiment, the polyurethane resin is a polyurethane resin obtained from a composition containing a polyol (A) and a polyfunctional isocyanate compound (B).

In a preferred embodiment, the polyol (A) has a number average molecular weight Mn of 400 to 20,000.

In a preferred embodiment, the equivalent ratio of the NCO group and the OH group in the polyol (A) and the polyfunctional isocyanate compound (B) is 0.3 to 1.0 as the NCO group / OH group.

In a preferred embodiment, the polyurethane resin is a polyurethane resin obtained from a composition containing a urethane prepolymer (C) and a polyfunctional isocyanate compound (B).

In a preferred embodiment, the equivalent ratio of the NCO group and the OH group in the urethane prepolymer (C) and the polyfunctional isocyanate compound (B) is 0.3 to 1.0 as the NCO group / OH group.

In a preferred embodiment, the urethane pressure-sensitive adhesive comprises a fatty acid ester.

In a preferred embodiment, the number average molecular weight Mn of the fatty acid ester is 200 to 400. [

The optical member of the present invention is one to which the surface protective film of the present invention is adhered.

The electronic member of the present invention is one to which the surface protective film of the present invention is adhered.

According to the present invention, even when bonding to an adherend having a large surface step difference, it is possible to provide a surface protective film which can achieve a sufficiently high adhesion rate because of excellent wettability and excellent step traceability. Further, an optical member and an electronic member to which such a surface protective film is adhered can be provided.

1 is a schematic sectional view of a surface protective film according to a preferred embodiment of the present invention.

The surface protective film of the present invention includes a pressure-sensitive adhesive layer. A release liner having releasability may be bonded to the adhesive surface side of the pressure-sensitive adhesive layer.

In the surface protective film of the present invention, preferably, the pressure-sensitive adhesive layer or the pressure-sensitive adhesive layer to which the release liner having releasability is adhered is located on the outermost layer.

The surface protective film of the present invention preferably has a base layer and a pressure-sensitive adhesive layer. The substrate layer may have only one layer or two or more layers. The surface protective film of the present invention may have any other suitable layer in addition to the base layer and the pressure-sensitive adhesive layer as long as the effect of the present invention is not impaired.

1 is a schematic sectional view of a surface protective film according to a preferred embodiment of the present invention. The surface protection film (10) comprises a base layer (1) and a pressure sensitive adhesive layer (2). The surface protective film of the present invention may further have any other suitable layer (not shown), if necessary.

The surface of the base layer 1 on which the pressure-sensitive adhesive layer 2 is not laid is not particularly limited insofar as the surface of the base layer 1 is formed of a fatty acid amide, a polyethyleneimine, a long- An additive or the like may be added to perform a mold release treatment or a coating layer containing any suitable releasing agent such as a silicone type, a long chain alkyl type, a fluorine type, or the like may be formed.

The thickness of the surface protective film of the present invention can be set to any appropriate thickness depending on the application. From the viewpoint of fully manifesting the effect of the present invention, it is preferably from 10 탆 to 300 탆, more preferably from 15 탆 to 250 탆, still more preferably from 20 탆 to 200 탆, particularly preferably from 25 탆 To 150 mu m.

The surface protective film of the present invention has a adhesion ratio of 80% or more when bonded to the surface of an adherend having a center line average roughness Ra of 0.2 탆 to 2 탆 only by its own weight. When the adhesive layer side is adhered to the adherend layer side only by its own weight with respect to the surface of the adherend having the center line average roughness Ra of 0.2 to 2 탆 at a self-weight of 80% or more, even when adhered to an adherend having a large surface step difference, Further, it is possible to provide a surface protective film capable of achieving a sufficiently high adhesion rate because of excellent step following property.

The surface-protective film of the present invention can improve the effect of the present invention. The surface-protective film of the present invention has a good adhesion ratio when the pressure-sensitive adhesive layer side is bonded only to the surface of the adherend having a center line average roughness Ra of 0.2 to 2 탆, , Preferably 82% or more, more preferably 84% or more, further preferably 86% or more, particularly preferably 88% or more, and most preferably 90% or more. The upper limit of the adhesion rate is preferably 100%.

The surface-protective film of the present invention can improve the effect of the present invention, so that the adhesion rate when the pressure-sensitive adhesive layer side is bonded only to the surface of the adherend having a center line average roughness Ra of 0.2 탆 by its own weight is preferably Is at least 80%, more preferably at least 85%, even more preferably at least 88%, particularly preferably at least 90%, and most preferably at least 92%. The upper limit of the adhesion rate is preferably 100%.

The surface-protective film of the present invention can be more effectively exhibited by the effect of the present invention, so that the adhesion rate when the pressure-sensitive adhesive layer side is bonded only to the surface of the adherend having a center line average roughness Ra of 0.3 m by self- Is at least 80%, more preferably at least 83%, even more preferably at least 86%, particularly preferably at least 88%, and most preferably at least 90%. The upper limit of the adhesion rate is preferably 100%.

The surface-protective film of the present invention is preferably such that the adhesion of the surface of the adherend having the center line average roughness Ra of 0.8 mu m when the pressure-sensitive adhesive layer side is bonded only with its own weight is preferable Is preferably 80% or more, more preferably 82% or more, still more preferably 84% or more, particularly preferably 86% or more, and most preferably 88% or more. The upper limit of the adhesion rate is preferably 100%.

The surface-protective film of the present invention can improve the effect of the present invention, so that the adhesion ratio when the pressure-sensitive adhesive layer side is bonded only to the surface of the adherend having the center line average roughness Ra of 1.1 m Is at least 80%, more preferably at least 82%, even more preferably at least 84%, particularly preferably at least 86%, and most preferably at least 87%. The upper limit of the adhesion rate is preferably 100%.

«Pressure-sensitive adhesive layer»

The pressure-sensitive adhesive layer contains a urethane-based pressure-sensitive adhesive containing a polyurethane-based resin as a main component. The content of the urethane pressure-sensitive adhesive in the pressure-sensitive adhesive layer is preferably 50% by weight to 100% by weight, more preferably 60% by weight to 100% by weight, still more preferably 70% by weight to 100% By weight, more preferably 80% by weight to 100% by weight, and most preferably 90% by weight to 100% by weight. By adjusting the content of the urethane pressure-sensitive adhesive in the pressure-sensitive adhesive layer within the above range, the surface protective film of the present invention is more excellent in wettability and superior in step-following property even when bonded to an adherend having a large surface step difference A sufficiently high adhesion rate can be achieved.

As for the thickness of the pressure-sensitive adhesive layer, any appropriate thickness can be adopted depending on the application. The thickness of the pressure-sensitive adhesive layer is preferably 1 占 퐉 to 100 占 퐉, more preferably 3 占 퐉 to 50 占 퐉, and still more preferably 5 占 퐉 to 30 占 퐉, from the viewpoint that the effect of the present invention can be further exerted . By adjusting the thickness of the pressure-sensitive adhesive layer within the above-mentioned range, the surface protective film of the present invention is more excellent in wettability even when bonded to an adherend having a large surface step difference, Rate can be achieved.

The pressure-sensitive adhesive layer can be produced by any suitable manufacturing method. Examples of such a production method include a method of forming a pressure-sensitive adhesive layer on a base layer by applying a composition as a pressure-sensitive adhesive layer forming material onto the base layer. Examples of such a coating method include roll coating, gravure coating, reverse coating, roll brush, spray coating, air knife coating, extrusion coating by a die coater, and the like.

The pressure-sensitive adhesive layer may contain, in addition to the urethane-based pressure-sensitive adhesive, any other appropriate components as long as the effect of the present invention is not impaired. Examples of such other components include a resin component other than the polyurethane resin, a tackifier, an inorganic filler, an organic filler, a metal powder, a pigment, a thinned product, a softener, an antioxidant, a conductive agent, an ultraviolet absorber, Surface lubricants, leveling agents, corrosion inhibitors, heat stabilizers, polymerization inhibitors, lubricants, solvents, catalysts and the like.

The content of the polyurethane resin in the urethane pressure-sensitive adhesive is preferably 50% by weight to 100% by weight, more preferably 70% by weight to 100% by weight, still more preferably 90% by weight to 100% by weight, Preferably 95% by weight to 100% by weight, and most preferably 98% by weight to 100% by weight. By adjusting the content ratio of the polyurethane resin in the urethane pressure-sensitive adhesive within the above range, the surface protective film of the present invention is excellent in wettability even when bonded to an adherend having a large surface step difference, Therefore, a sufficiently high adhesion rate can be achieved.

The urethane pressure-sensitive adhesive may contain, in addition to the polyurethane resin, any other appropriate components as long as the effect of the present invention is not impaired. Examples of such other components include a resin component other than the polyurethane resin, a tackifier, an inorganic filler, an organic filler, a metal powder, a pigment, a thinned product, a softener, an antioxidant, a conductive agent, an ultraviolet absorber, Surface lubricants, leveling agents, corrosion inhibitors, heat stabilizers, polymerization inhibitors, lubricants, solvents, catalysts and the like.

The urethane pressure sensitive adhesive may contain a fatty acid ester. The fatty acid ester may be one kind or two or more kinds.

The number average molecular weight Mn of the fatty acid ester is preferably 200 to 400, more preferably 210 to 395, still more preferably 230 to 380, particularly preferably 240 to 360, 350. By adjusting the number average molecular weight Mn of the fatty acid ester within the above range, the wetting rate can be further improved. If the number-average molecular weight Mn of the fatty acid ester is too small, there is a fear that the wetting rate may not be improved even when the number of the addition moieties is large. If the number-average molecular weight Mn of the fatty acid ester is too large, the curing property of the pressure-sensitive adhesive at the time of drying deteriorates, which may adversely affect other adhesive properties, not only the wetting property.

As the fatty acid ester, any suitable fatty acid ester can be employed as long as the effect of the present invention is not impaired. Examples of such fatty acid esters include polyoxyethylene bisphenol A lauric acid ester, butyl stearate, 2-ethylhexyl palmitate, 2-ethylhexyl stearate, behenic acid monoglyceride, 2-ethylhexanoic acid sebacate Methyl stearate, myristyl myristate, myristyl myristate, myristyl myristate, myristyl myristate, myristyl myristate, myristyl myristate, myristyl myristate, Pentaerythritol monostearate, pentaerythritol tetrapalmitate, stearyl stearate, isostearyl stearate, 2-ethylhexanoic acid triglyceride, butyl laurate, butyl stearate, And octyl oleate.

The blending ratio of the fatty acid ester in producing the urethane pressure-sensitive adhesive is preferably 5% by weight to 50% by weight, more preferably 7% by weight to 45% by weight, based on the polyol (A) More preferably 8% by weight to 40% by weight, particularly preferably 9% by weight to 35% by weight, and most preferably 10% by weight to 30% by weight.

The urethane pressure sensitive adhesive may contain an ionic liquid containing a fluoro organic anion. The urethane pressure sensitive adhesive contains an ionic liquid containing a fluoro organic anion, thereby providing an urethane pressure sensitive adhesive having an excellent antistatic property. The ionic liquid may be of only one type, or two or more types.

In the present invention, an ionic liquid means a molten salt (ionic compound) which exhibits a liquid phase at 25 占 폚.

As the ionic liquid, any suitable ionic liquid can be employed as far as it does not impair the effects of the present invention, provided that it is an ionic liquid containing a fluoro organic anion. The ionic liquid is preferably an ionic liquid composed of a fluoro organic anion and an onium cation. By employing an ionic liquid composed of a fluoro organic anion and an onium cation as the ionic liquid, it is possible to provide an urethane-based pressure sensitive adhesive having an extremely excellent antistatic property.

Any suitable onium cation can be employed as the onium cation that can constitute the ionic liquid, provided that the effect of the present invention is not impaired. The onium cation is preferably at least one selected from a nitrogen-containing onium cation, a sulfur-containing onium cation, and a phosphorus-containing onium cation. By selecting this onium cation, it is possible to provide an urethane-based pressure-sensitive adhesive which is extremely excellent in antistatic property.

The onium cation which can constitute the ionic liquid is preferably at least one kind of cation selected from the cations having the structures represented by the general formulas (1) to (5).

In the general formula (1), R _a represents a hydrocarbon group of 4 to 20 carbon atoms, may contain a hetero atom, R _b and R _c may be the same or different and represent a hydrogen atom or a hydrocarbon group of 1 to 16 carbon atoms And may contain a hetero atom. However, when the nitrogen atom contains a double bond, there is no R _c .

In the general formula (2), R _d represents a hydrocarbon group having 2 to 20 carbon atoms and may contain a hetero atom, and R _e , R _f , and R _{g, which} may be the same or different, A hydrocarbon group having 1 to 16 carbon atoms, and may contain a hetero atom.

In the general formula (3), R _h represents a hydrocarbon group of 2 to 20 carbon atoms, may contain a hetero atom, R _i , R _j and R _k may be the same or different, A hydrocarbon group having 1 to 16 carbon atoms, and may contain a hetero atom.

In the general formula (4), Z represents a nitrogen atom, a sulfur atom, or a phosphorus atom, and R ₁ , R _m , R _n and R _o are the same or different and each represents a hydrocarbon group of 1 to 20 carbon atoms , And a hetero atom. Provided that when Z is a sulfur atom, R _o is absent.

In the general formula (5), X represents a Li atom, a Na atom, or a K atom.

Examples of the cation represented by the general formula (1) include a pyridinium cation, a pyrrolidinium cation, a piperidinium cation, a cation having a pyrene skeleton, and a cation having a pyrrole skeleton.

Specific examples of the cation represented by the general formula (1) include, for example, 1-ethylpyridinium cation, 1-butylpyridinium cation, 1-hexylpyridinium cation, Butyl-3-methylpyridinium cation, 1-butyl-3-methylpyridinium cation, 1-butyl-4-methylpyridinium cation, Pyridinium cations such as 4-dimethylpyridinium cation and 1,1-dimethylpyrrolidinium cation; Methyl-1-propylpyrrolidinium cation, 1-methyl-1-butylpyrrolidinium cation, 1-methyl-1-pentylpyrrolidinium cation, 1- Methyl-1-heptylpyrrolidinium cation, a 1-ethyl-1-butylpyrrolidinium cation, a 1-ethyl-1-butylpyrrolidinium cation, Ethyl-1-hexylpyrrolidinium cation, 1-ethyl-1-heptylpyrrolidinium cation, 1,1-dipropylpyrrolidinium cation, 1-propyl-1-butyl Pyrrolidinium cations such as pyrrolidinium cation and 1,1-dibutylpyrrolidinium cation; 1-propylpiperidinium cation, 1-methylpiperidinium cation, 1-methyl-1-ethylpiperidinium cation, 1-methyl-1-propylpiperidinium cation, Methyl-1-heptylpiperidinium cation, 1-methyl-1-pentylpiperidinium cation, 1-methyl-1-pentylpiperidinium cation, Ethyl-1-butylpiperidinium cation, 1-ethyl-1-pentylpiperidinium cation, 1-ethyl-1-pentylpiperidinium cation, 1- Piperidinium cations such as propyl-1-butylpiperidinium cation, 1,1-dimethylpiperidinium cation, 1,1-dipropylpiperidinium cation and 1,1-dibutylpiperidinium cation; 2-methyl-1-pyridine cations; 1-ethyl-2-phenylindole cations; 1,2-dimethylindole cations; 1-ethylcarbazole cations; And the like.

Of these, preferred are 1-ethylpyridinium cation, 1-butylpyridinium cation, 1-hexylpyridinium cation, 1-ethyl-3-methyl Such as 1-butyl-3-methylpyridinium cation, 1-butyl-3-methylpyridinium cation, 1-butyl-4-methylpyridinium cation, Dimium cations; Methyl-1-propylpyrrolidinium cation, 1-methyl-1-butylpyrrolidinium cation, 1-methyl-1-pentylpyrrolidinium cation, 1- Methyl-1-heptylpyrrolidinium cation, a 1-ethyl-1-butylpyrrolidinium cation, a 1-ethyl-1-butylpyrrolidinium cation, Pyrrolidinium cations such as 1-pentylpyrrolidinium cation, 1-ethyl-1-hexylpyrrolidinium cation and 1-ethyl-1-heptylpyrrolidinium cation; Methyl-1-propylpiperidinium cation, 1-methyl-1-butylpiperidinium cation, 1-methyl-1-pentylpiperidinium cation, 1- Ethyl-1-propylpiperidinium cation, 1-ethyl-1-butylpiperidinium cation, 1-ethyl-1-pentylpiperidinium cation, Piperidinium cations such as 1-pentylpiperidinium cation, 1-ethyl-1-hexylpiperidinium cation, 1-ethyl-1-heptylpiperidinium cation and 1-propyl-1-butylpiperidinium cation; And more preferably 1-hexylpyridinium cation, 1-ethyl-3-methylpyridinium cation, 1-butyl-3-methylpyridinium cation, 1-octyl- A 1-methyl-1-propylpyrrolidinium cation, and a 1-methyl-1-propylpiperidinium cation.

Examples of the cation represented by the general formula (2) include an imidazolium cation, a tetrahydropyrimidinium cation, and a dihydropyrimidinium cation.

Specific examples of the cation represented by the general formula (2) include, for example, 1,3-dimethylimidazolium cation, 1,3-diethylimidazolium cation, 1-ethyl- 3-methylimidazolium cation, 1-hexyl-3-methylimidazolium cation, 1-decyl-3-methylimidazolium cation, 1- Methylimidazolium cation, 1-tetradecyl-3-methylimidazolium cation, 1,2-dimethyl-3-propylimidazolium cation, 1-ethyl-2,3-dimethylimidazolium cation Imidazolium cations such as a cation, 1-butyl-2,3-dimethylimidazolium cation and 1-hexyl-2,3-dimethylimidazolium cation; 1,3-dimethyl-1,4,5,6-tetrahydropyrimidinium cation, 1,2,3-trimethyl-1,4,5,6-tetrahydropyrimidinium cation, 1,2,3- Tetramethyl-1,4,5,6-tetrahydropyrimidinium cation, 1,2,3,5-tetramethyl-1,4,5,6-tetrahydropyrimidinium cation and the like, Midium cation; 1,3-dimethyl-1,4-dihydropyrimidinium cation, 1,3-dimethyl-1,6-dihydropyrimidinium cation, 1,2,3-trimethyl- 1,2,3-trimethyl-1,6-dihydropyrimidinium cation, 1,2,3,4-tetramethyl-1,4-dihydropyrimidinium cation, 1,2,3- Dihydropyrimidinium cations such as 4-tetramethyl-1,6-dihydropyrimidinium cation and the like; And the like.

Of these, preferred are 1,3-dimethylimidazolium cation, 1,3-diethylimidazolium cation, 1-ethyl-3-methyl Methylimidazolium cation, 1-hexyl-3-methylimidazolium cation, 1-octyl-3-methylimidazolium cation, 1-decyl-3-methylimidazolium cation, Methylimidazolium cation, 1-tetradecyl-3-methylimidazolium cation, and the like, and more preferably 1-ethyl-3-methylimidazolium cation Cation, and 1-hexyl-3-methylimidazolium cation.

Examples of the cation represented by the general formula (3) include a pyrazolium cation and a pyrazolinium cation.

Specific examples of the cation represented by the general formula (3) include 1-methylpyrazolium cation, 3-methylpyrazolium cation, 1-ethyl-2-methylpyrazolinium cation, , Pyrazolium cations such as 5-trimethylpyrazolium cation, 1-propyl-2,3,5-trimethylpyrazolium cation and 1-butyl-2,3,5-trimethylpyrazolium cation; 1-ethyl-2,3,5-trimethylpyrazolinium cation, 1-propyl-2,3,5-trimethylpyrazolinium cation, 1-butyl-2,3,5-trimethylpyrazolinium cation, Zolinium cations; And the like.

Examples of the cation represented by the general formula (4) include tetraalkylammonium cations, trialkylsulfonium cations and tetraalkylphosphonium cations, and those in which a part of the alkyl group is substituted with an alkenyl group, an alkoxyl group, And the like.

Specific examples of the cation represented by the general formula (4) include, for example, tetramethylammonium cation, tetraethylammonium cation, tetrabutylammonium cation, tetrapentylammonium cation, tetrahexylammonium cation, tetraheptylammonium cation, (2-methoxyethyl) ammonium cation, glycidyltrimethylammonium cation, trimethyldimethylammonium cation, trimethyldecylammonium cation, N, N-diethyl- There may be mentioned a cation selected from the group consisting of a sulfonium cation, a triethylsulfonium cation, a tributylsulfonium cation, a trihexylsulfonium cation, a diethylmethylsulfonium cation, a dibutylethylsulfonium cation, a dimethyldesylsulfonium cation, a tetramethylphosphonium cation, A phosphonium cation, a phosphonium cation, a tetrabutylphosphonium cation, a tetrahexylphosphonium cation, a tetraoctylphosphonium cation, Lee ethyl and methyl phosphonium cation, a tributyl ethyl phosphonium cation, a trimethyl decyl phosphonium cation, diallyldimethylammonium cation.

Among these, from the viewpoint of further manifesting the effect of the present invention, preferred are triethylmethylammonium cation, tributylethylammonium cation, trimethyldecylammonium cation, diethylmethylsulfonium cation, dibutylethylsulfonium A tetraalkylphosphonium cation, a trialkylsulfonium cation, a tetraalkylphosphonium cation, or a tetraalkylphosphonium cation such as N, N'-tetramethyldodecylphosphonium cation or a tetraalkylphosphonium cation such as dimethyldisilfonium cation, triethylmethylphosphonium cation, tributylethylphosphonium cation or trimethyldecylphosphonium cation, , N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium cation, glycidyltrimethylammonium cation, diallyldimethylammonium cation, N, N, N-dimethyl-N-ethyl-N-butylammonium cation, N, N-dimethyl-N-ethyl-N-pentylammonium cation, N, , N-dimethyl-N-ethyl-N-heptylammonium N, N-diethyl-N-propyl-N-butylammonium cation, N, N-dimethyl- N-dimethyl-N-propyl-N-pentylammonium cation, N, N-dimethyl- Dimethyl-N-butyl-N-hexylammonium cation, N, N-diethyl-N-butyl-N-heptylammonium cation, N, N, N-diethyl-N-methyl-N-pentylammonium cation, N, N-diethyl-N-methyl-N-propylammonium cation, , N, N-diethyl-N-methyl-N-heptylammonium cation, N, N-diethyl-N-propyl-N-pentylammonium cation, triethylpropylammonium cation, triethylpentylammonium cation, Ammonium cation, N, N-dipropyl-N-methyl-N-ethylammonium cation, N, N-dipropyl- N-dipropyl-N-methyl-N-pentylammonium cation, N, N-dipropyl-N, N-dihexylammonium cation, N, Ammonium cation, N, N-dibutyl-N-methyl-N-hexylammonium cation, trioctylmethylammonium cation and N-methyl-N-ethyl-N-propyl-N-pentylammonium cation. Preferably, it is a trimethylpropylammonium cation.

As the fluoroorganic anion capable of constituting the ionic liquid, any appropriate fluoro organic anion can be employed as long as the effect of the present invention is not impaired. Such a fluoro organic anion may be completely fluorinated (perfluorinated) or partially fluorinated.

Examples of such fluoro organic anions include fluorinated arylsulfonate, perfluoroalkanesulfonate, bis (fluorosulfonyl) imide, bis (perfluoroalkanesulfonyl) imide, cyano perfluoro (Perfluoroalkanesulfonyl) methide, tris (perfluoroalkanesulfonyl) methide, trifluoro (methanesulfonyl) methide, trifluoromethanesulfonylamide, Acetate, perfluoroalkylate, tris (perfluoroalkanesulfonyl) methide, (perfluoroalkanesulfonyl) trifluoroacetamide, and the like.

Among these fluoro organic anions, perfluoroalkylsulfonate, bis (fluorosulfonyl) imide and bis (perfluoroalkanesulfonyl) imide are more preferable. More specifically, for example, , Trifluoromethanesulfonate, pentafluoroethanesulfonate, heptafluoropropanesulfonate, nonafluorobutanesulfonate, bis (fluorosulfonyl) imide, bis (trifluoromethanesulfonyl) imide to be.

Specific examples of the ionic liquid may be selected from a combination of the cation component and the anionic component. Specific examples of such ionic liquids include 1-hexylpyridinium bis (fluorosulfonyl) imide, 1-ethyl-3-methylpyridinium trifluoromethanesulfonate, 1-ethyl- Methylpyridinium pentafluoroethanesulfonate, 1-ethyl-3-methylpyridinium heptafluoropropanesulfonate, 1-ethyl-3-methylpyridinium nonafluorobutanesulfonate, 1-butyl- Butyl-3-methylpyridinium bis (trifluoromethanesulfonyl) imide, 1-butyl-3-methylpyridinium bis (pentafluoroethanesulfonyl) imide, 1-octyl-4-methylpyridinium bis (fluorosulfonyl) imide, 1,1-dimethylpyrrolidinium bis (trifluoromethanesulfonyl) imide, (Trifluoromethanesulfonyl) imide, 1-methyl-1-propylpyrrolidinium bis (trifluoromethanesulfonyl) imide, 1-methyl-1-propylpyrrolidinium Methyl-1-butylpyrrolidinium bis (trifluoromethanesulfonyl) imide, 1-methyl-1-pentylpyrrolidinium bis (trifluoromethanesulfonyl) imide, 1-methyl-1-hexylpyrrolidinium bis (trifluoromethanesulfonyl) imide, 1-methyl-1-heptylpyrrolidinium bis (trifluoromethanesulfonyl) 1-propylpyrrolidinium bis (trifluoromethanesulfonyl) imide, 1-ethyl-1-butylpyrrolidinium bis (trifluoromethanesulfonyl) imide, 1-ethyl-1-pentylpyrrole Ethyl-1-hexylpyrrolidinium bis (trifluoromethanesulfonyl) imide, 1-ethyl-1-heptylpyrrolidinium bis (trifluoromethanesulfonyl) imide, Propyl-1-butylpyrrolidinium bis (trifluoromethanesulfonyl) imide, 1,1-dipropylpyrrolidinium bis (trifluoromethanesulfonyl) imide, 1,1-dibutylpyrrolidinium bis ( (Trifluoromethanesulfonyl) imide, 1-propylpiperidinium bis (trifluoromethanesulfonyl) imide, 1-pentylpiperidinium bis (trifluoromethanesulfonyl) imide, Dimethylpiperidinium bis (trifluoromethanesulfonyl) imide, 1-methyl-1-ethylpiperidinium bis (trifluoromethanesulfonyl) imide, 1-methyl-1-propylpiperidinium bis Methyl-1-propylpiperidinium bis (fluorosulfonyl) imide, 1-methyl-1-butylpiperidinium bis (trifluoromethanesulfonyl) imide, Methyl-1-pentylpiperidinium bis (trifluoromethanesulfonyl) imide, 1-methyl-1-hexylpiperidinium bis (trifluoromethanesulfonyl) imide, 1-methyl- 1-heptylpiperidinium bis (trifluoromethanesulfonyl) imide, 1-ethyl-1-propylpiperidinium bis (trifluoromethanesulfonyl) imide, 1-ethyl-1-butylpiperidinium Bis (trifluo Ethyl-1-pentylpiperidinium bis (trifluoromethanesulfonyl) imide, 1-ethyl-1-hexylpiperidinium bis (trifluoromethanesulfonyl) imide , 1-ethyl-1-heptylpiperidinium bis (trifluoromethanesulfonyl) imide, 1,1-dipropylpiperidinium bis (trifluoromethanesulfonyl) Butylpiperidinium bis (trifluoromethanesulfonyl) imide, 1,1-dibutylpiperidinium bis (trifluoromethanesulfonyl) imide, 1,1-dimethylpyrrolidinium bis (pentafluoro Methyl-1-ethylpyrrolidinium bis (pentafluoroethanesulfonyl) imide, 1-methyl-1-propylpyrrolidinium bis (pentafluoroethanesulfonyl) imide Methyl-1-butylpyrrolidinium bis (pentafluoroethanesulfonyl) imide, 1-methyl-1-pentylpyrrolidinium bis (pentafluoroethanesulfonyl) - hexylpyrrolidinium bis (pentaprene Methyl-1-heptylpyrrolidinium bis (pentafluoroethanesulfonyl) imide, 1-ethyl-1-propylpyrrolidinium bis (pentafluoroethanesulfonyl) imide, Ethyl-1-pentylpyrrolidinium bis (pentafluoroethanesulfonyl) imide, 1-ethyl-1-butylpyrrolidinium bis (pentafluoroethanesulfonyl) imide, 1-hexylpyrrolidinium bis (pentafluoroethanesulfonyl) imide, 1-ethyl-1-heptylpyrrolidinium bis (pentafluoroethanesulfonyl) imide, 1,1-dipropylpyrrolidinium bis (Pentafluoroethanesulfonyl) imide, 1-propyl-1-butylpyrrolidinium bis (pentafluoroethanesulfonyl) imide, 1,1-dibutylpyrrolidinium bis (pentafluoroethanesulfonyl) Imide, 1-propylpiperidinium bis (pentafluoroethanesulfonyl) imide, 1-pentylpiperidinium bis (pentafluoroethanesulfonyl) imide, 1,1-dimethylpiperidinium bis Pentafluoro Methyl-1-ethylpiperidinium bis (pentafluoroethanesulfonyl) imide, 1-methyl-1-propylpiperidinium bis (pentafluoroethanesulfonyl) imide, Methyl-1-butylpiperidinium bis (pentafluoroethanesulfonyl) imide, 1-methyl-1-pentylpiperidinium bis (pentafluoroethanesulfonyl) imide, Methyl-1-heptylpiperidinium bis (pentafluoroethanesulfonyl) imide, 1-ethyl-1-propylpiperidinium bis (pentafluoroethanesulfonyl) imide, Ethyl-1-butylpiperidinium bis (pentafluoroethanesulfonyl) imide, 1-ethyl-1-pentylpiperidinium bis (pentafluoroethanesulfonyl) imide 1-ethyl-1-hexylpiperidinium bis (pentafluoroethanesulfonyl) imide, 1-ethyl-1-heptylpiperidinium bis (pentafluoroethanesulfonyl) Dipropylpiperidinium bis (penta Propyl-1-butylpiperidinium bis (pentafluoroethanesulfonyl) imide, 1,1-dibutylpiperidinium bis (pentafluoroethanesulfonyl) imide, Ethyl-3-methylimidazolium trifluoromethanesulfonate, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, Ethyl-3-methylimidazolium heptafluoropropanesulfonate, 1-ethyl-3-methylimidazolium nonafluorobutanesulfonate, 1-ethyl-3-methylimidazolium bis (trifluoromethanesulfonyl) Ethyl-3-methylimidazolium bis (pentafluoroethanesulfonyl) imide, 1-ethyl-3-methylimidazoliumbis (fluorosulfonyl) imide, -3-methylimidazolium tris (trifluoromethanesulfonyl) methide, 1-butyl-3-methylimidazolium trifluoroacetate, 1-butyl-3-methylimidazolium heptaflu 3-methylimidazolium trifluoromethanesulfonate, 1-butyl-3-methylimidazolium perfluorobutanesulfonate, 1-butyl-3-methylimidazolium bis (tri 3-methylimidazolium bis (fluorosulfonyl) imide, 1-hexyl-3-methylimidazolium trifluoromethanesulfonate, 1-hexyl- Dimethyl-3-propylimidazolium bis (trifluoromethanesulfonyl) imide, 1-ethyl-2,3,5-trimethylpyrazoliumbis (trifluoromethanesulfonyl) , 3,5-trimethylpyrazoliumbis (trifluoromethanesulfonyl) imide, 1-butyl-2,3,5-trimethylpyrazoliumbis (trifluoromethanesulfonyl) imide, , 3,5-trimethylpyrazoliumbis (pentafluoroethanesulfonyl) imide, 1-propyl-2,3,5-trimethylpyrazoliumbis (pentafluoroethanesulfonyl) imide, , 3,5-trimethylpyrazoliumbis (penta Ethyl-2,3,5-trimethylpyrazolium (trifluoromethanesulfonyl) trifluoroacetamide, 1-propyl-2,3,5-trimethylpyrazolium ( (Trifluoromethanesulfonyl) trifluoroacetamide, 1-butyl-2,3,5-trimethylpyrazolium (trifluoromethanesulfonyl) trifluoroacetamide, trimethylpropylammonium bis (trifluoromethanesulfonyl) N-dimethyl-N-ethyl-N-butylammonium bis (trifluoromethanesulfonyl) imide, N-dimethyl-N-ethyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl- N-dimethyl-N-ethyl-N-heptylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl- (Trifluoromethanesulfo (Trifluoromethanesulfonyl) imide, N, N-dimethyl-N-propyl-N-butylammonium bis (trifluoromethanesulfonyl) imide, (Trifluoromethanesulfonyl) imide, N, N-dimethyl-N-propyl-N-hexylammonium bis (trifluoromethylsulfonyl) imide, N-dimethyl-N-butyl-N-hexylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl- N-dimethyl-N-butyl-N-heptylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-pentyl-N-hexylammonium bis (Trifluoromethanesulfonyl) imide, N, N-dimethyl-N, N-dihexylammonium bis (trifluoromethanesulfonyl) imide, trimethylheptylammonium bis (trifluoromethanesulfonyl) imide , N, N-diethyl-N-methyl-N-propylammonium bis (trifluoromethane N, N-diethyl-N-methyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, N, N-diethyl-N-propyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, triethylpropylammonium bis (trifluoromethanesulfonyl) imide, (Trifluoromethanesulfonyl) imide, triethylheptylammonium bis (trifluoromethanesulfonyl) imide, N, N-dipropyl-N-methyl- N, N-dipropyl-N-methyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, N, N-dipropyl- N, N-dipropyl-N, N-dibutylammonium bis (trifluoromethanesulfonyl) imide, N, N-dibutyl -N-methyl-N-pentylammonium bis (trifluoromethanesulfo Imide, N, N-dibutyl-N-methyl-N-hexylammonium bis (trifluoromethanesulfonyl) imide, trioctylmethylammonium bis (trifluoromethanesulfonyl) Propyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, 1-butylpyridinium (trifluoromethanesulfonyl) trifluoroacetamide, 1-butyl- (Trifluoromethanesulfonyl) trifluoroacetamide, 1-ethyl-3-methylimidazolium (trifluoromethanesulfonyl) trifluoroacetamide, tetrahexylammonium bis (trifluoromethane) (Pentafluoroethanesulfonyl) imide, diallyldimethylammonium trifluoromethanesulfonate, diallyldimethylammonium bis (trifluoromethanesulfonyl) imide, diallyldimethylammonium bis (pentafluoroethanesulfonyl) imide, N , N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium trifluoromethanesulfonate, N, (Trifluoromethanesulfonyl) imide, N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium bis (pentafluoroethane Glycidyltrimethylammonium bis (trifluoromethanesulfonyl) imide, glycidyltrimethylammonium bis (pentafluoroethanesulfonyl) imide, glycidyltrimethylammonium trifluoromethanesulfonate, glycidyltrimethylammonium bis (Pentafluoroethanesulfonyl) imide, lithium bis (trifluoromethanesulfonyl) imide, lithium bis (trifluoromethanesulfonyl) imide, diallyldimethylbis ≪ RTI ID = 0.0 > rosulfonyl) < / RTI > imide.

Among these ionic liquids, more preferred are 1-hexylpyridinium bis (fluorosulfonyl) imide, 1-ethyl-3-methylpyridinium trifluoromethanesulfonate, 1-ethyl- Methylpyridinium heptafluoropropanesulfonate, 1-ethyl-3-methylpyridinium nonafluorobutanesulfonate, 1-butyl-3-methylpyridinium Methyl-3-methylpyridinium bis (trifluoromethanesulfonyl) imide, 1-octyl-4-methylpyridinium bis (fluorosulfonyl) imide, 1-methyl Propylpyrrolidinium bis (fluorosulfonyl) imide, 1-methyl-1-propylpiperidinium bis (trifluoromethanesulfonyl) imide, (Trifluoromethanesulfonyl) imide, 1-methyl-1-propylpiperidinium bis (fluorosulfonyl) imide, 1-ethyl-3-methylimidazolium trifluoro Ethyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide, 1-ethyl-3-methyl (methylsulfonyl) imide, Imidazolium bis (fluorosulfonyl) imide, 1-hexyl-3-methylimidazolium bis (fluorosulfonyl) imide, trimethylpropylammonium bis (trifluoromethanesulfonyl) imide, lithium bis (Trifluoromethanesulfonyl) imide, and lithium bis (fluorosulfonyl) imide.

As the ionic liquid, a commercially available liquid may be used, but it may be synthesized as follows. The method for synthesizing an ionic liquid is not particularly limited as long as an intended ionic liquid can be obtained, but generally it is described in "Frontier and Future of Ionic Liquid - Development" (published by CMC Publishing Co., Ltd.) A halide method, a hydroxide method, an acid ester method, an emulsion formation method, a neutralization method and the like, which are the same as those described above.

Examples of the method of synthesizing a nitrogen containing onium salt are described below with reference to the halide method, the hydroxide method, the acid ester method, the method of forming an amorphous form, and the neutralization method. Other examples of the sulfur containing onium salt, Other ionic liquids can also be obtained by the same method.

The halide method is a method which is carried out by a reaction as shown in the reaction formulas (1) to (3). First, a halide is obtained by reacting with a tertiary amine and an alkyl halide (Reaction formula (1), chlorine, bromine and iodine are used as halogens).

The obtained halide is reacted with an acid (HA) or a salt (MA and M are cations forming a salt with an objective anion such as ammonium, lithium, sodium, potassium) having an anion structure (A ^- The reaction is carried out to obtain a target ionic liquid (R ₄ NA).

The hydroxide method is a method which is carried out by a reaction as shown in the reaction formulas (4) to (8). First, a halide (R ₄ NX), the ion exchange membrane method electrolysis (reaction formula (4)), OH-type ion exchange resin method (reaction scheme 5), or silver oxide reaction (Scheme 6) with (Ag ₂ O) hydroxide (R ₄ NOH) (chlorine, bromine and iodine are used as halogen).

The target ionic liquid (R ₄ NA) is obtained by using the reaction of the reaction formulas (7) to (8) with the obtained hydroxide in the same manner as the halogenation method.

The acid ester method is a method which is carried out by a reaction as shown in reaction formulas (9) to (11). First, an acid ester is obtained by reacting a tertiary amine (R ₃ N) with an acid ester (reaction formula (9)). Examples of the acid ester include esters of inorganic acids such as sulfuric acid, sulfuric acid, phosphoric acid, phosphorous acid, and carbonic acid, Esters of organic acids such as formic acid, formic acid, etc.) are used.

The target ionic liquid (R ₄ NA) is obtained by using the reaction of the reaction formulas (10) to (11) in the same manner as in the halogenation method for the acid ester obtained. Further, by using methyl trifluoromethane sulfonate, methyl trifluoroacetate or the like as the acid ester, a direct ionic liquid can be obtained.

The neutralization method is a method which is carried out by a reaction as shown in the reaction formula (12). Tertiary amine and _{CF 3 COOH, CF 3 SO 3} H, (CF 3 SO 2) 2 NH, (CF 3 SO 2) 3 CH, (C 2 F 5 SO 2) 2 is obtainable by reacting an organic acid, such as NH have.

R in the above-mentioned reaction formulas (1) to (12) represents hydrogen or a hydrocarbon group having 1 to 20 carbon atoms, and may contain a hetero atom.

The amount of the ionic liquid to be blended varies depending on the compatibility of the polymer to be used and the ionic liquid. Therefore, it is generally 0.001 to 50 parts by weight based on 100 parts by weight of the polyurethane resin More preferably 0.01 part by weight to 30 parts by weight, particularly preferably 0.01 part by weight to 20 parts by weight, most preferably 0.01 part by weight to 10 parts by weight Wealth. By adjusting the blending amount of the ionic liquid within the above range, it is possible to provide an urethane pressure-sensitive adhesive excellent in antistatic property. If the amount of the ionic liquid is less than 0.01 part by weight, sufficient antistatic properties may not be obtained. If the above amount of the ionic liquid is more than 50 parts by weight, contamination of the adherend tends to increase.

The urethane pressure-sensitive adhesive may contain a modified silicone oil. When the urethane pressure-sensitive adhesive contains a modified silicone oil, the effect of the present invention can be expressed more effectively.

When the urethane pressure-sensitive adhesive contains a modified silicone oil, its content is preferably 0.001 to 50 parts by weight, more preferably 0.01 to 40 parts by weight, based on 100 parts by weight of the polyurethane resin, Preferably 0.01 to 30 parts by weight, particularly preferably 0.01 to 20 parts by weight, and most preferably 0.01 to 10 parts by weight. By adjusting the content of the modified silicone oil within the above-mentioned range, the effect of the present invention can be expressed more effectively.

As the modified silicone oil, any appropriate modified silicone oil may be employed as long as the effect of the present invention is not impaired. As such a modified silicone oil, for example, a modified silicone oil available from Shin-Etsu Chemical Co., Ltd. may be mentioned.

The modified silicone oil is preferably a polyether-modified silicone oil. By employing a polyether-modified silicone oil, the effect of the present invention can be expressed more effectively.

Examples of the polyether-modified silicone oil include a side chain-type polyether-modified silicone oil and a polyether-modified silicone oil of both ends. Of these, polyether-modified silicone oil of both ends is preferable in that the effect of the present invention can be sufficiently and more effectively expressed.

As the polyurethane resin, any suitable polyurethane resin can be employed as long as the effect of the present invention is not impaired. The polyurethane resin is preferably a polyurethane resin obtained from a composition containing a polyol (A) and a polyfunctional isocyanate compound (B), or a urethane prepolymer containing a urethane prepolymer (C) and a polyfunctional isocyanate compound (B) Is a polyurethane resin obtained from a composition. By employing the same as the polyurethane resin, the surface protective film of the present invention is superior in wettability even when bonded to an adherend having a large surface step difference, and is more excellent in step following property, Rate can be achieved.

The polyurethane resin may contain any suitable other components as long as the effect of the present invention is not impaired. Examples of such other components include a resin component other than the polyurethane resin, a tackifier, an inorganic filler, an organic filler, a metal powder, a pigment, a thinned product, a softener, an antioxidant, a conductive agent, an ultraviolet absorber, Surface lubricants, leveling agents, corrosion inhibitors, heat stabilizers, polymerization inhibitors, lubricants, solvents, catalysts and the like.

The polyurethane resin preferably includes an antioxidant such as an antioxidant, an ultraviolet absorber, or a light stabilizer. Since the polyurethane resin contains a deterioration inhibitor, it is possible to obtain excellent adhesive residue retention property, for example, it is difficult for the adhesive to remain on the adherend even after it is adhered to the adherend and then stored in a heated state. Therefore, in the surface protective film of the present invention, contamination of the adherend can be reduced. The deterioration inhibitor may be one kind or two or more kinds. As the deterioration inhibitor, particularly preferably, it is an antioxidant.

Examples of the antioxidant include a radical chain inhibitor and a peroxide dissolution inhibitor.

Examples of the radical chain inhibitor include phenol-based antioxidants and amine-based antioxidants.

Examples of the releasing of the peroxide include a sulfur-based antioxidant and a phosphorus-based antioxidant.

Examples of the phenol-based antioxidant include a monophenol-based antioxidant, a bisphenol-based antioxidant, and a polymer-based phenol-based antioxidant.

Examples of the monophenol antioxidant include 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di- - (3,5-di-t-butyl-4-hydroxyphenyl) propionate.

Examples of the bisphenol-based antioxidant include 2,2'-methylenebis (4-methyl-6-t-butylphenol), 2,2'-methylenebis (4-ethyl- (3-methyl-6-t-butylphenol), 4,4'-butylidenebis (3-methyl- Dimethyl-2- [? - (3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy] ethyl] 2,4,8,10-tetraoxaspiro [5,5] undecane .

Examples of the polymer type phenolic antioxidant include 1,1,3-tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane, 1,3,5- (3,5-di-t-butyl-4-hydroxybenzyl) benzene, tetrakis- [methylene- Propionate] methane, bis [3,3'-bis- (4'-hydroxy-3'-t-butylphenyl) butyric acid] glycol ester, 1,3,5- Di-t-butyl-4'-hydroxybenzyl) -S-triazine-2,4,6- (1H, 3H, 5H) trione and tocophenol.

Examples of the sulfur-based antioxidant include dilauryl 3,3'-thiodipropionate, dimyristyl 3,3'-thiodipropionate, distearyl 3,3'-thiodipropionate, etc. .

Examples of the phosphorus antioxidant include triphenyl phosphite, diphenyl isodecyl phosphite, phenyl diisodecyl phosphite and the like.

Examples of the ultraviolet absorber include benzophenone ultraviolet absorbers, benzotriazole ultraviolet absorbers, salicylic acid ultraviolet absorbers, oxalanilide ultraviolet absorbers, cyanoacrylate ultraviolet absorbers, triazine-based ultraviolet absorbers, and the like.

Examples of the benzophenone ultraviolet absorber include 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2- 4-dodecyloxybenzophenone, 2,2'-dihydroxy-4-dimethoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2-hydroxy- Methoxy-5-sulfobenzophenone, bis (2-methoxy-4-hydroxy-5-benzoylphenyl) methane and the like.

Examples of benzotriazole ultraviolet absorbers include 2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-5'-tert- butylphenyl) benzotriazole, Butylphenyl) benzotriazole, 2- (2'-hydroxy-3'-tert-butyl-5'-methylphenyl) -5- Chlorobenzotriazole, 2- (2'-hydroxy-3 ', 5'-di (tert-butylphenyl) (2 ' -hydroxy-3 ' - (3 ", 4 ", 5 ' Methylphenyl] benzotriazole, 2,2'-methylenebis [4- (1,1,3,3-tetramethylbutyl) -6- ( 2H-benzotriazol-2-yl) phenol], and [2 (2'-hydroxy-5'-methacryloxyphenyl) -2H-benzotriazole.

Examples of the salicylic acid-based ultraviolet absorber include phenyl salicylate, p-tert-butylphenyl salicylate, and p-octylphenyl salicylate.

Examples of the cyanoacrylate ultraviolet absorber include 2-ethylhexyl-2-cyano-3,3'-diphenylacrylate, ethyl-2-cyano-3,3'-diphenylacrylate and the like .

Examples of the light stabilizer include hindered amine light stabilizers and ultraviolet light stabilizers.

Examples of hindered amine light stabilizers include [bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate], bis (1,2,2,6,6-pentamethyl -4-piperidyl) sebacate, methyl 1,2,2,6,6-pentamethyl-4-piperidyl sebacate, and the like.

Examples of the ultraviolet stabilizer include nickel bis (octylphenyl) sulfide, [2,2'-thiobis (4-tert-octylphenolate)] n-butylamine nickel, nickel complex- -butyl-4-hydroxybenzyl-phosphoric acid monoethylate, nickel-dibutyldithiocarbamate, benzoate type filler, and nickel-dibutyldithiocarbamate.

<Polyurethane-based resin obtained from a composition containing polyol (A) and polyfunctional isocyanate compound (B)

The polyurethane resin obtained from the composition containing the polyol (A) and the polyfunctional isocyanate compound (B) is preferably obtained by curing a composition containing the polyol (A) and the polyfunctional isocyanate compound (B) Is a polyurethane resin to be obtained.

The polyol (A) may be only one type, or two or more types.

The polyfunctional isocyanate compound (B) may be one kind or two or more kinds.

The polyol (A) is preferably a polyester polyol, a polyether polyol, a polycaprolactone polyol, a polycarbonate polyol, or a castor oil-based polyol, for example. The polyol (A) is more preferably a polyether polyol.

The polyester polyol can be obtained, for example, by an esterification reaction between a polyol component and an acid component.

Examples of the polyol component include ethylene glycol, diethylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 1,3-propanediol, 2,4-diethyl-1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,8-octanediol, -Methyl-1,8-octanediol, 1,8-decanediol, octadecanediol, glycerin, trimethylolpropane, pentaerythritol, hexanetriol, polypropylene glycol and the like. Examples of the acid component include succinic acid, methylsuccinic acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, 1,12-dodecanedioic acid, 1,14-tetradecanedioic acid, dimeric acid, 4-cyclohexane dicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, isophthalic acid, terephthalic acid, 1,4-naphthalene dicarboxylic acid, 4-cyclohexane dicarboxylic acid, 4'-biphenyldicarboxylic acid, and their acid anhydrides.

Examples of the polyether polyols include water, low molecular polyols (propylene glycol, ethylene glycol, glycerin, trimethylol propane, pentaerythritol, etc.), bisphenols (such as bisphenol A), dihydroxybenzenes , Hydroquinone and the like) as an initiator and addition polymerization of an alkylene oxide such as ethylene oxide, propylene oxide, butylene oxide and the like. Specific examples thereof include polyethylene glycol, polypropylene glycol, and polytetramethylene glycol.

Examples of the polycaprolactone polyols include caprolactone polyester diols obtained by ring-opening polymerization of cyclic ester monomers such as? -Caprolactone and? -Valerolactone.

Examples of the polycarbonate polyol include polycarbonate polyols obtained by polycondensation reaction of the polyol component and phosgene; The above-mentioned polyol component is mixed with the carbonic acid di (methane) such as dimethyl carbonate, diethyl carbonate, dipropyl carbonate, diisopropyl carbonate, dibutyl carbonate, ethylbutyl carbonate, ethylene carbonate, propylene carbonate, diphenyl carbonate, Polycarbonate polyols obtained by ester exchange condensation of esters; A copolymerized polycarbonate polyol obtained by using two or more of the above polyol components in combination; A polycarbonate polyol obtained by esterifying the above various polycarbonate polyols and a carboxyl group-containing compound; A polycarbonate polyol obtained by etherifying the various polycarbonate polyols and a hydroxyl group-containing compound; A polycarbonate polyol obtained by transesterifying various polycarbonate polyols and an ester compound; A polycarbonate polyol obtained by transesterifying the various polycarbonate polyols and a hydroxyl group-containing compound; A polyester polycarbonate polyol obtained by polycondensation reaction of the various polycarbonate polyols and a dicarboxylic acid compound; A copolymerized polyether polycarbonate polyol obtained by copolymerizing the various polycarbonate polyols and an alkylene oxide; And the like.

Examples of the castor oil-based polyol include a castor oil-based polyol obtained by reacting a castor oil fatty acid with the polyol component. Specifically, there may be mentioned, for example, castor oil type polyols obtained by reacting castor oil fatty acid with polypropylene glycol.

The number average molecular weight Mn of the polyol (A) is preferably 400 to 20,000, more preferably 500 to 17,000, still more preferably 600 to 15,000, and particularly preferably 800 to 12,000. By adjusting the number average molecular weight Mn of the polyol (A) within the above range, the surface protective film of the present invention is superior in wettability even when bonded to an adherend having a large surface step difference, Therefore, a sufficiently high adhesion rate can be achieved.

The polyol (A) preferably contains a polyol (A1) having three OH groups and a number average molecular weight Mn of 8,000 to 20,000. The polyol (A1) may be one kind alone, or two or more kinds.

The content of the polyol (A1) in the polyol (A) is preferably 70% by weight or more, more preferably 70% by weight to 100% by weight, and still more preferably 70% by weight to 90% by weight. By adjusting the content ratio of the polyol (A1) in the polyol (A) within the above range, the surface protective film of the present invention is superior in wettability even when bonded to an adherend having a large surface step difference, It is possible to achieve a sufficiently high adhesion rate.

The number average molecular weight Mn of the polyol (A1) is preferably 8,000 to 20,000, more preferably 8,000 to 18,000, still more preferably 8500 to 17,000, still more preferably 9,000 to 16,000, 9500 to 15,500, and most preferably from 10,000 to 15,000. By adjusting the number average molecular weight Mn of the polyol (A1) to fall within the above range, the surface protective film of the present invention is excellent in wettability even when bonded to an adherend having a large surface step difference, Therefore, a sufficiently high adhesion rate can be achieved.

The polyol (A) may contain a polyol (A2) having 3 or more OH groups and a number average molecular weight Mn of 5000 or less. The polyol (A2) may be one kind alone, or two or more kinds. The number average molecular weight Mn of the polyol (A2) is preferably 500 to 5000, more preferably 800 to 4500, further preferably 1000 to 4000, particularly preferably 1000 to 3500, and most preferably, Lt; / RTI &gt; If the number average molecular weight Mn of the polyol (A2) deviates from the above-mentioned range, there is a possibility that the riseability of the adhesive strength with time may be increased, and the excellent reworkability may not be exhibited. The polyol (A2) is preferably a polyol (triol) having three OH groups, a polyol (tetraol) having four OH groups, a polyol (pentanol) having five OH groups, a polyol having six OH groups Hexanol).

The total amount of the polyol (A) as the polyol (A2) in the polyol (tetraol) having 4 OH groups, the polyol (pentanol) having 5 OH groups and the polyol having 6 OH groups (hexanol) Is preferably 10% by weight or less, more preferably 7% by weight or less, further preferably 6% by weight or less, particularly preferably 5% by weight or less. At least one of polyol (tetraol) having 4 OH groups, polyol (pentanol) having 5 OH groups, and polyol (hexanol) having 6 OH groups in the polyol (A) , It is possible to provide an urethane-based pressure-sensitive adhesive which is further superior in transparency.

The content of the polyol (A2) in the polyol (A) is preferably 30% by weight or less, and more preferably 0% by weight to 30% by weight. By adjusting the content ratio of the polyol (A2) in the polyol (A) within the above range, the surface protective film of the present invention is superior in wettability even when bonded to an adherend having a large surface step difference, It is possible to achieve a sufficiently high adhesion rate.

The content of the polyol having a number average molecular weight Mn of not more than 5,000 in the polyol (A2) having 4 or more OH groups therein is preferably less than 10% by weight, more preferably less than 8% by weight %, More preferably not more than 7 wt%, particularly preferably not more than 6 wt%, and most preferably not more than 5 wt%. If the proportion of the polyol having a number average molecular weight Mn of 4 or more in the polyol (A2) and having a number average molecular weight Mn of 5,000 or less is 10% by weight or more based on the total amount of the polyol (A), the urethane-based tackifier tends to be whitened, .

The polyfunctional isocyanate compound (B) may be one kind or two or more kinds.

As the polyfunctional isocyanate compound (B), any suitable polyfunctional isocyanate compound which can be used for the urethanization reaction can be employed. Examples of the polyfunctional isocyanate compound (B) include a polyfunctional aliphatic isocyanate compound, a polyfunctional alicyclic isocyanate, and a polyfunctional aromatic isocyanate compound.

Examples of the polyfunctional aliphatic isocyanate compound include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 1,3-butylene diisocyanate, Methylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, and the like.

Examples of the polyfunctional alicyclic isocyanate compound include 1,3-cyclopentene diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, isophorone diisocyanate, Isocyanate, hydrogenated xylylene diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated tetramethyl xylylene diisocyanate, and the like.

Examples of the polyfunctional aromatic diisocyanate compound include phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 2,2'-diphenylmethane diisocyanate, 4,4'-di Phenylmethane diisocyanate, 4,4'-toluidine diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4'-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, xylylene diisocyanate, .

Examples of the polyfunctional isocyanate compound (B) include trimethylolpropane adducts of various polyfunctional isocyanate compounds as described above, burettes obtained by reacting with water, trimer having an isocyanurate ring, and the like. These may be used in combination.

The equivalent ratio of the NCO group and the OH group in the polyol (A) and the polyfunctional isocyanate compound (B) is preferably from 0.3 to 1.0, more preferably from 0.3 to 0.9, Is preferably 0.3 to 0.8, particularly preferably 0.3 to 0.7, and most preferably 0.3 to 0.6. By adjusting the equivalent ratio of the NCO group / OH group to the above range, the surface protective film of the present invention has better wettability and better followability of step even when bonded to an adherend having a large surface step difference A sufficiently high adhesion rate can be achieved.

The content of the polyfunctional isocyanate compound (B) is preferably 2.7% by weight to 8.8% by weight, more preferably 2.7% by weight to 8.0% by weight, based on the polyol (A) , More preferably 2.7 wt% to 7.1 wt%, particularly preferably 2.7 wt% to 6.2 wt%, and most preferably 2.7 wt% to 5.3 wt%. By adjusting the content ratio of the polyfunctional isocyanate compound (B) within the above range, the surface protective film of the present invention is excellent in wettability even when bonded to an adherend having a large surface step difference, A sufficiently high adhesion rate can be achieved.

Specifically, the polyurethane resin is preferably obtained by curing a composition containing the polyol (A) and the polyfunctional isocyanate compound (B).

As a method for obtaining a polyurethane resin by curing a composition containing a polyol (A) and a polyfunctional isocyanate compound (B), a method such as a urethane polymerization reaction method using bulk polymerization or solution polymerization, Any suitable method may be employed.

In order to cure the composition containing the polyol (A) and the polyfunctional isocyanate compound (B), a catalyst is preferably used. Examples of such catalysts include organometallic compounds, tertiary amine compounds, and the like.

Examples of the organometallic compounds include iron-based compounds, tin-based compounds, titanium-based compounds, zirconium-based compounds, lead-based compounds, cobalt-based compounds, and zinc-based compounds. Among them, an iron-based compound and a tin-based compound are preferable from the viewpoints of the reaction rate and the time of use of the pressure-sensitive adhesive layer.

Examples of the iron-based compound include iron acetylacetonate and 2-ethylhexanoate.

As the tin compound, for example, dibutyltin dichloride, dibutyltin oxide, dibutyltin dibromide, dibutyltin maleate, dibutyltin dilaurate, dibutyltin diacetate, dibutyltin sulfide , Tributyltin methoxide, tributyltin acetate, triethyltin ethoxide, tributyltin ethoxide, dioctyltin oxide, dioctyltin dilaurate, tributyltin chloride, tributyltin trichloroacetate, 2-ethylhexanoate tin and the like.

Examples of the titanium-based compound include dibutyltitanium dichloride, tetrabutyl titanate, butoxy titanium trichloride and the like.

Examples of the zirconium compound include zirconium naphthenate, zirconium acetylacetonate, and the like.

Examples of the lead-based compound include lead oleate, lead 2-ethylhexanoate, lead benzoate, lead naphthenate, and the like.

Examples of the cobalt compound include cobalt 2-ethylhexanoate, cobalt benzoate, and the like.

Examples of the zinc-based compound include zinc naphthenate and zinc 2-ethylhexanoate.

Examples of the tertiary amine compound include triethylamine, triethylenediamine, 1,8-diazabicyclo- (5,4,0) -undecene-7, and the like.

The catalyst may be of only one type, or two or more types. In addition, a catalyst and a crosslinking retarder may be used in combination. The amount of the catalyst is preferably 0.02 wt% to 0.10 wt%, more preferably 0.02 wt% to 0.08 wt%, still more preferably 0.02 wt% to 0.06 wt% with respect to the polyol (A) 0.02% to 0.05% by weight. By adjusting the amount of the catalyst within the above range, the surface protective film of the present invention is superior in wettability even when bonded to an adherend having a large surface step difference, and is more excellent in step following property, Can be achieved.

The composition containing the polyol (A) and the polyfunctional isocyanate compound (B) may contain any other appropriate components as long as the effect of the present invention is not impaired. Examples of such other components include a resin component other than a polyurethane resin, a tackifier, an inorganic filler, an organic filler, a metal powder, a pigment, a thin material, a softener, an antioxidant, a conductive agent, an ultraviolet absorber, A surface lubricant, a leveling agent, a corrosion inhibitor, a heat stabilizer, a polymerization inhibitor, a lubricant, a solvent, a catalyst and the like.

<Polyurethane-based resin obtained from a composition containing a urethane prepolymer (C) and a polyfunctional isocyanate compound (B)

The polyurethane resin obtained from the composition containing the urethane prepolymer (C) and the polyfunctional isocyanate compound (B) may be any polyurethane resin obtained by using a so-called &quot; urethane prepolymer &quot; can do.

The polyurethane resin obtained from the composition containing the urethane prepolymer (C) and the polyfunctional isocyanate compound (B) can be obtained, for example, by mixing a polyurethane polyol as the urethane prepolymer (C) and a polyfunctional isocyanate compound (B) A polyurethane resin obtained from a composition. The urethane prepolymer (C) may be of only one type, or two or more types. The polyfunctional isocyanate compound (B) may be one kind or two or more kinds.

The polyurethane polyol as the urethane prepolymer (C) is preferably obtained by reacting the polyester polyol (a1) and the polyether polyol (a2) with the organic polyisocyanate compound (a3) in the presence or in the absence of a catalyst will be.

As the polyester polyol (a1), any suitable polyester polyol can be used. Examples of such polyester polyol (a1) include a polyester polyol obtained by reacting an acid component with a glycol component. Examples of the acid component include terephthalic acid, adipic acid, azelaic acid, sebacic acid, phthalic anhydride, isophthalic acid and trimellitic acid. Examples of the glycol component include ethylene glycol, propylene glycol, diethylene glycol, butylene glycol, 1,6-hexane glycol, 3-methyl-1,5-pentanediol, 3,3'-dimethylolheptane, Polyoxypropylene glycol, 1,4-butanediol, neopentyl glycol, butylethylpentanediol, and polyol components such as glycerin, trimethylolpropane and pentaerythritol. Examples of the polyester polyol (a1) include polyester polyols obtained by ring-opening polymerization of lactones such as polycaprolactone, poly (beta -methyl- -valerolactone) and polyvalerolactone.

The molecular weight of the polyester polyol (a1) can be from a low molecular weight to a high molecular weight. The number average molecular weight of the polyester polyol (a1) is preferably 500 to 5000. When the number average molecular weight is less than 500, the reactivity is increased, and gelation tends to occur. If the number average molecular weight exceeds 5000, the reactivity is lowered, and further, the cohesive force of the polyurethane polyol itself may be reduced. The amount of the polyester polyol (a1) to be used is preferably 10 to 90 mol% in the polyol constituting the polyurethane polyol.

As the polyether polyol (a2), any suitable polyether polyol can be used. Examples of the polyether polyol (a2) include low molecular weight polyols such as water, propylene glycol, ethylene glycol, glycerin, and trimethylolpropane as initiators, and ethylene oxide, propylene oxide, And a polyether polyol obtained by polymerizing an oxirane compound such as hydrofuran. Specific examples of the polyether polyol (a2) include polyether polyols having two or more functional groups such as polypropylene glycol, polyethylene glycol, and polytetramethylene glycol.

The molecular weight of the polyether polyol (a2) can be from a low molecular weight to a high molecular weight. The molecular weight of the polyether polyol (a2) is preferably 1,000 to 5,000. When the number average molecular weight is less than 1000, the reactivity is increased, and gelation tends to occur. If the number average molecular weight exceeds 5000, the reactivity is lowered, and further, the cohesive force of the polyurethane polyol itself may be reduced. The amount of the polyether polyol (a2) to be used is preferably 20% by mole to 80% by mole in the polyol constituting the polyurethane polyol.

The polyetherpolyol (a2) may be partially substituted with a glycol such as ethylene glycol, 1,4-butanediol, neopentyl glycol, butylethylpentanediol, glycerin, trimethylolpropane or pentaerythritol, ethylene diamine, N -Aminoethylethanolamine, isophorone diamine, xylylenediamine, and the like.

As the polyether polyol (a2), only a bifunctional polyether polyol may be used, or a polyether polyol having a number average molecular weight of 1,000 to 5,000 and at least three hydroxyl groups in one molecule may be partially or wholly used . As the polyether polyol (a2), when a polyether polyol having an average molecular weight of 1000 to 5000 and having at least three or more hydroxyl groups in one molecule is partially or wholly used, the balance between adhesive strength and re-peelability can be improved . In such a polyether polyol, if the number average molecular weight is less than 1000, the reactivity becomes high and gelation tends to occur. Further, in such a polyether polyol, when the number average molecular weight exceeds 5000, the reactivity is lowered, and further, the cohesive force of the polyurethane polyol itself may be reduced. The number average molecular weight of such a polyether polyol is more preferably from 2500 to 3500.

As the organic polyisocyanate compound (a3), any suitable organic polyisocyanate compound can be used. Examples of the organic polyisocyanate compound (a3) include aromatic polyisocyanates, aliphatic polyisocyanates, aromatic aliphatic polyisocyanates, alicyclic polyisocyanates, and the like.

Examples of the aromatic polyisocyanate include 1,3-phenylene diisocyanate, 4,4'-diphenyl diisocyanate, 1,4-phenylenediisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4- Tolylene diisocyanate, 2,4,6-triisocyanate toluene, 1,3,5-triisocyanate benzene, diindenydine diisocyanate, 4,4'-toluene diisocyanate, 2,6-tolylene diisocyanate, Diphenyl ether diisocyanate, 4,4 ', 4 "-triphenyl methane triisocyanate, and the like.

Examples of the aliphatic polyisocyanate include aliphatic polyisocyanates such as trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 2,3-butylene diisocyanate, Dodecamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, and the like.

Examples of the aromatic aliphatic polyisocyanate include ω, ω'-diisocyanate-1,3-dimethylbenzene, ω'-diisocyanate-1,4-dimethylbenzene, ω, ω'-diisocyanate- 4-diethylbenzene, 1,4-tetramethylxylylene diisocyanate, 1,3-tetramethylxylylene diisocyanate, and the like.

Examples of the alicyclic polyisocyanate include 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate, 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane Diisocyanate, methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 4,4'-methylenebis (cyclohexylisocyanate), 1,4-bis (isocyanatemethyl) cyclohexane, 1,4-bis (isocyanatomethyl) cyclohexane, and the like.

As the organic polyisocyanate compound (a3), a trimethylolpropane adduct, a buret resin reacted with water, a trimer having an isocyanurate ring, and the like can also be used in combination.

Any suitable catalyst may be used as the catalyst that can be used to obtain the polyurethane polyol. Examples of such catalysts include tertiary amine compounds and organometallic compounds.

Examples of the tertiary amine compound include triethylamine, triethylenediamine, 1,8-diazabicyclo (5,4,0) -undecene-7 (DBU) and the like.

Examples of the organometallic compounds include tin compounds and non-saponified compounds.

Examples of the tin compound include dibutyltin dichloride, dibutyltin oxide, dibutyltin dibromide, dibutyltin dimaleate, dibutyltin dilaurate (DBTDL), dibutyltin diacetate, di Tributyl tin acetate, tributyl tin acetate, triethyl tin ethoxide, tributyl tin ethoxide, dioctyl tin oxide, tributyltin chloride, tributyltin trichloro Acetate, tin 2-ethylhexanoate, and the like.

As non-saponified compounds, for example, titanium-based compounds such as dibutyltitanium dichloride, tetrabutyl titanate, and butoxy titanium trichloride; Lead compounds such as lead oleate, lead 2-ethylhexanoate, lead benzoate and lead naphthene; Iron-based compounds such as 2-ethylhexanoate and iron acetylacetonate; Cobalt compounds such as cobalt benzoate and cobalt 2-ethylhexanoate; Zinc-based compounds such as zinc naphthenate, and zinc 2-ethylhexanoate; Zirconium compounds such as zirconium naphthenate; And the like.

In the case where a catalyst is used to obtain a polyurethane polyol and a system in which two kinds of polyols such as a polyester polyol and a polyether polyol exist, there is a difference in reactivity thereof, so that in a single catalyst system, Is likely to occur. Therefore, when two kinds of catalysts are used in obtaining the polyurethane polyol, it becomes easy to control the reaction rate, catalyst selectivity, etc., and this problem can be solved. Examples of combinations of these two types of catalysts include tertiary amines / organometallic compounds, tin compounds / non-tin compounds and tin compounds / tin compounds, preferably tin compounds / tin compounds, And a combination of dibutyltin dilaurate and 2-ethylhexanoic acid tin. The compounding ratio thereof is preferably 2-ethylhexanoate / dibutyltin dilaurate in a weight ratio of preferably less than 1, more preferably 0.2 to 0.6. If the compounding ratio is 1 or more, gelation tends to occur due to the balance of catalytic activity.

When the catalyst is used to obtain the polyurethane polyol, the amount of the catalyst to be used is preferably 0.01 to 1.0 wt% based on the total amount of the polyester polyol (a1), the polyether polyol (a2) and the organic polyisocyanate compound (a3) to be.

When a catalyst is used to obtain the polyurethane polyol, the reaction temperature is preferably less than 100 占 폚, more preferably 85 占 폚 to 95 占 폚. When the temperature is higher than 100 ° C, there is a possibility that the reaction rate and control of the crosslinking structure become difficult, and it is difficult to obtain a polyurethane polyol having a predetermined molecular weight.

When a polyurethane polyol is obtained, a catalyst may not be used. In that case, the reaction temperature is preferably 100 ° C or more, and more preferably 110 ° C or more. When the polyurethane polyol is obtained in the absence of a catalyst, the reaction is preferably carried out for 3 hours or more.

Examples of the method for obtaining the polyurethane polyol include: 1) a method in which a polyester polyol, a polyether polyol, a catalyst, and an organic polyisocyanate are all charged into a flask; 2) a polyester polyol, a polyether polyol, Followed by dropping and adding the organic polyisocyanate. As a method for obtaining a polyurethane polyol, the method 2) is preferred in controlling the reaction.

When a polyurethane polyol is obtained, any appropriate solvent may be used. Examples of such a solvent include methyl ethyl ketone, ethyl acetate, toluene, xylene, acetone, and the like. Among these solvents, toluene is preferable.

As the polyfunctional isocyanate compound (B), the above-mentioned compounds can be used.

The composition containing the urethane prepolymer (C) and the polyfunctional isocyanate compound (B) may contain any other suitable components as long as the effect of the present invention is not impaired. Examples of such other components include a resin component other than a polyurethane resin, a tackifier, an inorganic filler, an organic filler, a metal powder, a pigment, a thin material, a softener, an antioxidant, a conductive agent, an ultraviolet absorber, A surface lubricant, a leveling agent, a corrosion inhibitor, a heat stabilizer, a polymerization inhibitor, a lubricant, a solvent, a catalyst and the like.

As a method for producing a polyurethane resin obtained from a composition containing a urethane prepolymer (C) and a polyfunctional isocyanate compound (B), a method of producing a polyurethane resin by using a so-called "urethane prepolymer" Can be employed.

The number average molecular weight Mn of the urethane prepolymer (C) is preferably 1,000 to 100,000.

The equivalent ratio of the NCO group and the OH group in the urethane prepolymer (C) and the polyfunctional isocyanate compound (B) is preferably from 0.3 to 1.0, more preferably from 0.3 to 0.9, as the NCO group / OH group, More preferably from 0.3 to 0.8, particularly preferably from 0.3 to 0.7, and most preferably from 0.3 to 0.6. By adjusting the equivalent ratio of the NCO group / OH group to the above range, the surface protective film of the present invention has better wettability and better followability of step even when bonded to an adherend having a large surface step difference A sufficiently high adhesion rate can be achieved.

The content of the polyfunctional isocyanate compound (B) is preferably 1.1% by weight to 3.6% by weight, more preferably 1.1% by weight to 3.2% by weight, based on the urethane prepolymer (C) %, More preferably 1.1 wt% to 2.9 wt%, particularly preferably 1.1 wt% to 2.5 wt%, and most preferably 1.1 wt% to 2.1 wt%. By adjusting the content ratio of the polyfunctional isocyanate compound (B) within the above range, the surface protective film of the present invention is excellent in wettability even when bonded to an adherend having a large surface step difference, A sufficiently high adhesion rate can be achieved.

&Quot; Base layer &quot;

As for the thickness of the base layer, any appropriate thickness can be adopted depending on the application. The thickness of the substrate layer is preferably 5 to 300 탆, more preferably 10 to 250 탆, still more preferably 15 to 200 탆, and particularly preferably 20 to 150 탆.

The substrate layer may be a single layer or a laminate of two or more layers. The base layer may be stretched.

As the material of the base layer, any suitable material may be employed depending on the application. Examples thereof include plastics, paper, metal films, and nonwoven fabrics. Preferably, it is a plastic. The substrate layer may be composed of one kind of material or two or more kinds of materials. For example, it may be composed of two or more kinds of plastics.

Examples of the plastic include a polyester resin, a polyamide resin, and a polyolefin resin. Examples of the polyester-based resin include polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate. Examples of the polyolefin-based resin include a homopolymer of an olefin monomer and a copolymer of an olefin monomer. Specific examples of the polyolefin-based resin include homopolypropylene; Propylene-based copolymers such as a block system, a random system and a graft system having an ethylene component as a copolymerization component; Reactor TPO; Ethylene polymers such as low density, high density, linear low density and ultra low density; Ethylene / propylene copolymer, ethylene / vinyl acetate copolymer, ethylene / methyl acrylate copolymer, ethylene · ethyl acrylate copolymer, ethylene · butyl acrylate copolymer, ethylene · methacrylic acid copolymer, ethylene · methyl methacrylate copolymer And the like; And the like.

The base layer may contain any suitable additives, if necessary. Examples of additives that can be contained in the base layer include antioxidants, ultraviolet absorbers, light stabilizers, antistatic agents, fillers, pigments and the like. The kind, quantity, and amount of the additive that may be contained in the base layer may be appropriately set according to the purpose. Particularly, when the material of the base layer is plastic, it is preferable to contain some of the above additives for the purpose of preventing deterioration or the like. From the viewpoint of improving weatherability and the like, additives such as an antioxidant, an ultraviolet absorber, a light stabilizer and a filler are particularly preferable.

As the antioxidant, any suitable antioxidant may be employed. Examples of such an antioxidant include a phenol-based antioxidant, a phosphorus-based heat stabilizer, a lactone-based heat stabilizer, a sulfur-based heat stabilizer, and a phenol-phosphorus antioxidant. The content of the antioxidant is preferably 1% by weight or less, more preferably 0.5% by weight or less based on the base resin of the base layer (when the base layer is a blend, the blend is the base resin) And preferably 0.01% by weight to 0.2% by weight.

As the ultraviolet absorber, any appropriate ultraviolet absorber can be employed. Examples of such ultraviolet absorbers include benzotriazole ultraviolet absorbers, triazine ultraviolet absorbers, benzophenone ultraviolet absorbers, and the like. The content of the ultraviolet absorber is preferably not more than 2% by weight, more preferably not more than 1% by weight based on the base resin forming the base layer (when the base layer is a blend, the blend is the base resin) By weight, more preferably 0.01% by weight to 0.5% by weight.

As the light stabilizer, any suitable light stabilizer can be employed. Examples of such light stabilizers include hindered amine light stabilizers, benzoate light stabilizers, and the like. The content of the light stabilizer is preferably 2% by weight or less, more preferably 1% by weight or less, based on the base resin forming the base layer (when the base layer is a blend, the blend is the base resin) By weight, more preferably 0.01% by weight to 0.5% by weight.

As the filler, any suitable filler can be employed. As such a filler, for example, an inorganic filler and the like can be mentioned. Specific examples of the inorganic filler include carbon black, titanium oxide, zinc oxide and the like. The content of the filler is preferably 20% by weight or less, more preferably 10% by weight or less, based on the base resin forming the base layer (when the base layer is a blend, the blend is the base resin) More preferably 0.01% by weight to 10% by weight.

As the additive, inorganic, low molecular weight and high molecular weight antistatic agents such as surfactants, inorganic salts, polyhydric alcohols, metal compounds and carbon are preferably used for the purpose of imparting antistatic properties. Particularly, from the viewpoints of keeping contamination and tackiness, high molecular weight antistatic agents and carbon are preferable.

&Lt; Method for producing surface protective film &

The surface protective film of the present invention can be produced by any suitable method. As such a production method, for example,

(1) Method of forming a pressure-sensitive adhesive layer A method of applying a solution or heat melt of a material on a substrate layer,

(2) a method in which a pressure-sensitive adhesive layer applied and formed in the form of a separator is adhered onto the base layer,

(3) a method of extruding and forming a pressure-sensitive adhesive layer forming material on a base layer,

(4) a method of extruding the base layer and the pressure-sensitive adhesive layer into two layers or multiple layers,

(5) a method in which the pressure-sensitive adhesive layer is laminated on the base layer or a method in which the pressure-sensitive adhesive layer is laminated on the two layers together with the laminate layer,

(6) a method of laminating a pressure-sensitive adhesive layer and a base layer forming material such as a film or a laminate layer in two layers or in multiple layers,

, And the like.

As the coating method, for example, a roll coater method, a comma coater method, a die coater method, a reverse coater method, a silk screen method, a gravure coater method and the like can be used.

«Use of surface protective film»

The surface protective film of the present invention can be used in any suitable application. Preferably, the surface protective film of the present invention is used for protecting the surface of an optical member or an electronic member, for example, since the surface protective film of the present invention has very little contamination on an adherend and is preferably excellent in wettability and reworkability do. Examples of the optical member include a touch panel using an LCD or an LCD, a color filter used in an LCD, and a polarizing plate.

The members, for example, the optical member or the electronic member to which the surface protective film of the present invention is adhered, can be bonded and peeled by hand several times with the bonded surface protective film.

That is, the optical member of the present invention is one to which the surface protective film of the present invention is adhered. Further, the electronic member of the present invention is one to which the surface protective film of the present invention is adhered.

[Example]

Hereinafter, the present invention will be described in detail by way of examples, but the present invention is not limited to these examples at all. Tests and evaluation methods in Examples and the like are as follows. Unless otherwise noted, the term "part" means "part by weight" unless otherwise specified, and "%" means "% by weight" unless otherwise specified.

<Measurement of Adhesion>

The surface protective film with a separator was cut to a size of 25 mm in width and 80 mm in length and the separator was peeled off and laminated at a pressure of 0.25 MPa on an AGS1 polarizer (Nitto Denko Co., width 70 mm, length 100 mm) Respectively. After laminating, (1) the laminate was allowed to stand in an environment of 23 ° C × 50% RH for 30 minutes, (2) left for 1 week under an environment of 50 ° C, (3) left in a 60 ° C × 90% (4) After leaving for one week under an environment of 85 占 폚, using a universal tensile tester (trade name: TCM-1kNB, manufactured by Minebea K.K.) at a peel rate of 300 mm / min and a peel angle of 180 The peel adhesion was measured. The measurement was carried out in an environment of 23 캜 x 50% RH.

&Lt; Measurement of wetting speed &

The surface protective film with a separator was cut into a size of 25 mm in width and 100 mm in length to obtain an evaluation sample. An AGS1 polarizing plate (manufactured by Nitto Denko Co., Ltd., width: 70 mm, length: 100 mm) was used as an adherend, the separator of the evaluation sample was peeled off, one side of the width side was fixed to the width side end of the adherend, The end of the unthreaded garment was lifted and the time from when the hand was released to the time when it spread to 100 mm was measured (unit: s / 2.5 cm x 10 cm). The speed was calculated based on the time taken. The case where the speed was 5 cm 2 / s or more was evaluated as &amp; cir &amp;, and the case where the speed was less than 5 cm 2 / s was evaluated as &

<Measurement of Peeling Voltage>

The surface protective film with a separator was cut into a size of 70 mm in width and 130 mm in length and the separator was peeled off. Thereafter, an AGS1 polarizing plate (Nitto Denko Co., Ltd.) with which the acrylic plate (thickness 1 mm, width 70 mm, length 100 mm) Ltd., width: 70 mm, length: 100 mm). At this time, the surface protective film had been evacuated by 30 mm from the glass. After standing for 1 day under an environment of 23 占 폚 占 50% RH, one end of the glass sheet, which was 30 mm clearance, was fixed to the automatic winding machine and peeled off at a peeling angle of 150 占 and a peeling rate of 10 m / min. Then, the peeling electrification voltage was measured with a potential meter (KSD-0103, manufactured by Kasuga Denki KK) fixed at a position 10 cm away from the surface protective film. This measurement was carried out in an environment of 23 캜 x 50% RH.

&Lt; Measurement of center line average roughness Ra &

An aluminum plate with an AGS1 polarizing plate (manufactured by Nitto Denko Co., Ltd.), an aluminum plate, and an aluminum plate rubbed with a sandpaper having a predetermined particle size was set on a stage of ZYGO New View 7300 (manufactured by Canon Marketing Japan) Were measured. The grain size of the sandpaper used to rub the aluminum plate is (1) 320 and (2) 100.

&Lt; Measurement of adhesion rate when bonding is carried out only by self weight >

An aluminum plate subjected to roughness measurement was prepared with an AGS1 polarizing plate (manufactured by Nitto Denko Corporation, width 70 mm, length 100 mm) and ZYGO New View 7300 (manufactured by Canon Marketing Japan Co., Ltd.), and a separator- The separator of the protective film was peeled off, one end of the width side was fixed to the adherend, the end of the non-fixed width side was lifted, and the hand was placed and adhered to each adherend with only the self weight of the film. Thereafter, the adhesion area was calculated by VHX-100F (Keyens Co., Ltd.), and the adhesion ratio was calculated from the adhesion ratio (%) = (adhesion area / total area).

[Example 1]

As a polyol, 85 parts by weight of a polyol having three OH groups, that is, FRONINOL S3011 (manufactured by Asahi Glass Co., Ltd., Mn = 10000), a polyol SANONIX GP-3000 having three OH groups (manufactured by SANYO KASEI KABUSHIKI KAISHA) , Mn = 3000) as a polyfunctional isocyanate compound and 2 parts by weight of SANNICYS GP-1000 (manufactured by Sanyo Chemical Industries, Ltd., Mn = 1000), which is a polyol having three OH groups, was used as a polyfunctional alicyclic , 2.7 parts by weight of an isocyanate compound, Coronate HX (manufactured by Nippon Polyurethane Industry Co., Ltd.), 0.04 parts by weight of a catalyst (trade name: acetylacetonate ferric chloride, manufactured by Nippon Kagaku Sanayaku K.K.), Irganox 1010 : 0.50 parts by weight, ELECEL AS110 (ionic liquid, manufactured by Dai-ichi Kogyo Seiyaku K.K.): 1.50 parts by weight, KF6004 (polyether-modified silicone, Shin-Etsu Chemical Co., Ltd.) With solvent And 241 parts by weight of ethyl acetate were added and stirred with a disper to obtain a urethane pressure-sensitive adhesive composition.

The obtained urethane pressure-sensitive adhesive composition was applied to a substrate "LM Mirror S10" (thickness 38 μm, manufactured by Dorey Co., Ltd.) comprising a polyester resin so as to have a thickness of 10 μm after drying with a fountain roll and dried at 130 ° C. for 30 seconds And then dried. Thus, a pressure-sensitive adhesive layer containing the urethane-based pressure-sensitive adhesive (1) was produced on the base material.

Subsequently, a silicone-treated surface of a separator containing a polyester resin having a thickness of 25 占 퐉, which had been subjected to a silicone treatment on one surface, was bonded to the surface of the pressure-sensitive adhesive layer to obtain a surface protective film (1) with a separator.

The results are shown in Table 1.

[Examples 2 to 8]

The procedure of Example 1 was repeated except that the blending amount of Coronate HX (manufactured by Nippon Polyurethane Industry Co., Ltd.), which is a polyfunctional alicyclic isocyanate compound, as the polyfunctional isocyanate compound was changed as shown in Table 1, ) To (8).

The results are shown in Table 1.

[Examples 9 to 11]

As the polyfunctional isocyanate compound, the blending amount of Coronate HX (Nippon Polyurethane High Kogyo Co., Ltd.), which is a polyfunctional alicyclic isocyanate compound, was changed as shown in Table 2 and, as shown in Table 2, myristic acid isopropyl (9) to (11) with a separator were obtained in the same manner as in Example 1 except that 10 parts by weight of an antistatic agent (trade name: Exepal IPM, Mn = 270)

The results are shown in Table 2.

[Examples 12 to 14]

As the polyfunctional isocyanate compound, the blending amount of Coronate HX (Nippon Polyurethane High Kogyo Co., Ltd.), which is a polyfunctional alicyclic isocyanate compound, was changed as shown in Table 2 and, as shown in Table 2, myristic acid isopropyl (12) to (14) with a separator were obtained in the same manner as in Example 1, except that 30 parts by weight of an antistatic agent (trade name: Exepal IPM, Mn = 270)

The results are shown in Table 2.

[Examples 15 to 17]

As the polyfunctional isocyanate compound, the amount of coronate HX (manufactured by Nippon Polyurethane Industry Co., Ltd.), which is a multifunctional alicyclic isocyanate compound, was changed as shown in Table 3, and as a fatty acid ester, 2-ethylhexanoate (15) to (17) with a separator were obtained in the same manner as in Example 1, except that 10 parts by weight of a surfactant (trade name: Salacos 816T, Mn = 368, manufactured by OILO GROUP CORPORATION)

The results are shown in Table 3.

[Examples 18 to 20]

As the polyfunctional isocyanate compound, the amount of coronate HX (manufactured by Nippon Polyurethane Industry Co., Ltd.), which is a polyfunctional alicyclic isocyanate compound, was changed as shown in Table 3, and as a fatty acid ester, 2-ethylhexanoate (20) was obtained in the same manner as in Example 1, except that 30 parts by weight of a surfactant (trade name: Salacos 816T, Mn = 368, manufactured by OILO GROUP CORPORATION)

The results are shown in Table 3.

[Example 21]

100 parts by weight of &quot; Saibabin SH-109H &quot; (solid content: 54%, fatty acid ester, manufactured by Toyo Ink) as a urethane prepolymer, and polyfunctional alicyclic isocyanate compound Coronate HX (manufactured by Nippon Polyurethane High- (Ion-exchange liquid, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.): 1.50 parts by weight, KF6004 (polyether-modified silicone, Shin-Etsu Chemical Co., Ltd.): 0.01 part by weight And 208 parts by weight of toluene as a diluting solvent were mixed and stirred with a disper to obtain a urethane pressure-sensitive adhesive composition.

The obtained urethane pressure-sensitive adhesive composition was applied to a substrate "LM Mirror S10" (thickness 38 μm, manufactured by Dorey Co., Ltd.) comprising a polyester resin so as to have a thickness of 10 μm after drying with a fountain roll and dried at 130 ° C. for 30 seconds And then dried. Thus, a pressure-sensitive adhesive layer containing the urethane-based pressure-sensitive adhesive (21) was prepared on the substrate.

Subsequently, a silicone-treated surface of a separator including a polyester resin having a thickness of 25 占 퐉, which had been subjected to silicone treatment on one side, was bonded to the surface of the pressure-sensitive adhesive layer to obtain a surface protective film 21 with a separator.

The results are shown in Table 4.

[Examples 22 to 25]

The procedure of Example 21 was repeated except that the blending amount of Coronate HX (Nippon Polyurethane High Kogyo Co., Ltd.), which is a polyfunctional alicyclic isocyanate compound, as a polyfunctional isocyanate compound was changed as shown in Table 4, ) To (25).

The results are shown in Table 4.

[Comparative Examples 1 to 3]

The procedure of Example 1 was repeated except that the blending amount of Coronate HX (manufactured by Nippon Polyurethane Industry Co., Ltd.), which is a polyfunctional alicyclic isocyanate compound, as the polyfunctional isocyanate compound was changed as shown in Table 5, ) To (C3).

The results are shown in Table 5.

[Comparative Example 4]

The procedure of Example 21 was repeated except that the blending amount of Coronate HX (Nippon Polyurethane High Kogyo Co., Ltd.), which is a polyfunctional alicyclic isocyanate compound, as the polyfunctional isocyanate compound was changed as shown in Table 5, ).

The results are shown in Table 5.

[Example 26]

The separator of the surface protective film with a separator obtained in Example 1 was peeled off and adhered to a polarizing plate (trade name: "TEG1465DUHC" manufactured by Nitto Denko Corporation) as an optical member to obtain an optical member to which the surface protective film was adhered.

[Example 27]

The separator of the surface protecting film with a separator obtained in Example 9 was peeled off and adhered to a polarizing plate (trade name: "TEG1465DUHC" manufactured by Nitto Denko Corporation) as an optical member to obtain an optical member to which the surface protecting film was adhered.

[Example 28]

The separator of the surface protective film with a separator obtained in Example 15 was peeled off and adhered to a polarizing plate (trade name: "TEG1465DUHC" manufactured by Nitto Denko Corporation) as an optical member to obtain an optical member to which the surface protective film was adhered.

[Example 29]

The separator of the surface protective film with a separator obtained in Example 21 was peeled off and adhered to a polarizing plate (trade name: "TEG1465DUHC" manufactured by Nitto Denka Co., Ltd.) as an optical member to obtain an optical member to which the surface protective film was adhered.

[Example 30]

The separator of the surface protective film with a separator obtained in Example 1 was peeled off and adhered to a conductive film (trade name "ELEKTRA V270L-TFMP", trade name, manufactured by Nitto Denko Corporation) Member.

[Example 31]

The separator of the surface protective film with a separator obtained in Example 9 was peeled off and adhered to a conductive film (trade name "ELEKTRYST V270L-TFMP", manufactured by Nitto Denko Co., Ltd.) Member.

[Example 32]

The separator of the surface protective film with a separator obtained in Example 15 was peeled off and adhered to a conductive film (trade name "ELEKTRYST V270L-TFMP", manufactured by Nitto Denko Co., Ltd.) Member.

[Example 33]

The separator of the surface protecting film with a separator obtained in Example 21 was peeled off and adhered to a conductive film (trade name "ELEKTRYST V270L-TFMP", trade name, manufactured by Nitto Denko Corporation) Member.

The surface protective film of the present invention can be used in any suitable application. Preferably, the surface protective film of the present invention is preferably used for protecting the surface of an optical member or an electronic member.

1: substrate layer
2: Pressure-sensitive adhesive layer
10: Surface protective film

Claims (10)

A surface protective film comprising a pressure-sensitive adhesive layer,
The pressure-sensitive adhesive layer contains a urethane pressure-sensitive adhesive containing a polyurethane resin as a main component,
Wherein the adhesion ratio when the pressure sensitive adhesive layer side is bonded only to the surface of the adherend having a center line average roughness Ra of 0.2 to 2 占 퐉 only by its own weight is 80%
Surface protection film. The surface protective film according to claim 1, wherein the polyurethane resin is a polyurethane resin obtained from a composition containing a polyol (A) and a polyfunctional isocyanate compound (B). The surface protective film according to claim 2, wherein the polyol (A) has a number average molecular weight Mn of 400 to 20,000. The surface protective film according to claim 2, wherein the equivalent ratio of the NCO group and the OH group in the polyol (A) and the polyfunctional isocyanate compound (B) is 0.3 to 1.0 as an NCO group / OH group. The surface protective film according to claim 1, wherein the polyurethane resin is a polyurethane resin obtained from a composition containing a urethane prepolymer (C) and a polyfunctional isocyanate compound (B). The surface protective film according to claim 5, wherein the equivalent ratio of the NCO group and the OH group in the urethane prepolymer (C) and the polyfunctional isocyanate compound (B) is 0.3 to 1.0 as an NCO group / OH group. The surface protective film according to claim 1, wherein the urethane pressure-sensitive adhesive comprises a fatty acid ester. The surface protective film according to claim 7, wherein the fatty acid ester has a number average molecular weight Mn of 200 to 400. An optical member to which the surface protective film according to any one of claims 1 to 8 is adhered. An electronic member to which the surface protecting film according to any one of claims 1 to 8 is adhered.

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