JP6533323B2 - Method for producing antistatic surface protection film - Google Patents

Description

  The present invention relates to a pressure-sensitive adhesive composition and a surface protection film. More specifically, the present invention relates to an antistatic surface protective film having an antistatic performance. More specifically, the present invention provides a method for producing an antistatic surface protective film that has excellent anti-peeling antistatic performance with little contamination to an adherend and that does not deteriorate with time, and an antistatic surface protective film.

Optical films such as polarizing plates, retardation plates, lens films for displays, antireflection films, hard coat films, transparent conductive films for touch panels, and optical products such as displays using the films The surface protective film is bonded to the surface of the optical film to prevent the surface from being soiled or damaged in a later step. The appearance inspection of an optical film which is a product may be performed with the surface protective film adhered to the optical film in order to peel off the surface protective film and to save labor for bonding again to enhance work efficiency.
Heretofore, a surface protective film provided with an adhesive layer on one side of a substrate film is generally used in order to prevent adhesion of scratches and dirt in the manufacturing process of an optical product. The surface protective film is bonded to the optical film through the pressure-sensitive adhesive layer with a slight adhesion. The pressure-sensitive adhesive layer has a slight adhesion because it can be easily peeled off when the used surface protective film is peeled off from the surface of the optical film, and the adhesive is an adherend. The purpose is to prevent the film from adhering and remaining on the optical film (so-called generation of adhesive residue).

In recent years, in the production process of liquid crystal display panels, for controlling the display screen of a liquid crystal display panel by a peeling charge voltage generated when the surface protection film bonded on the optical film is peeled and removed. The phenomenon that circuit components such as driver ICs are destroyed and the phenomenon that the alignment of liquid crystal molecules is damaged are occurring although the number of occurrence is small.
Further, in order to reduce the power consumption of the liquid crystal display panel, the driving voltage of the liquid crystal material is becoming lower, and accordingly, the breakdown voltage of the driver IC is also becoming lower. In recent years, it has been required to set the peeling voltage within the range of +0.7 kV to -0.7 kV.
For this reason, when peeling a surface protection film from the film for optics which is a to-be-adhered body, in order to prevent the problem by the peeling charge voltage being high, the adhesive layer containing the antistatic agent for restraining a peeling charge voltage low A surface protection film using a has been proposed.

For example, Patent Document 1 discloses a surface protection film using an adhesive comprising an alkyltrimethyl ammonium salt, a hydroxyl group-containing acrylic polymer, and a polyisocyanate.
Patent Document 2 discloses a pressure-sensitive adhesive composition comprising an ionic liquid and an acrylic polymer having an acid value of 1.0 or less, and a pressure-sensitive adhesive sheet using the same.
Further, Patent Document 3 discloses a pressure-sensitive adhesive composition comprising an acrylic polymer, a polyether polyol compound, an alkali metal salt treated with an anion adsorbing compound, and a surface protection film using the same.
Further, Patent Document 4 discloses a pressure-sensitive adhesive composition comprising an ionic liquid, an alkali metal salt, a polymer having a glass transition temperature of 0 ° C. or less, and a surface protection film using the same.
Patent Documents 5 and 6 show that polyether modified silicone is mixed in the adhesive layer of the surface protective film.

JP 2005-131957 A JP 2005-330464 A JP 2005-314476 A Unexamined-Japanese-Patent No. 2006-152235 JP, 2009-275128, A Patent No. 4537450 gazette

  In the above-mentioned Patent Documents 1 to 4, the antistatic agent is added to the inside of the pressure-sensitive adhesive layer, but as the thickness of the pressure-sensitive adhesive layer becomes thicker and as the elapsed time passes, the surface protective film is bonded With respect to the adherend, the amount of the antistatic agent transferred from the pressure-sensitive adhesive layer to the adherend is increased. Further, in the case of an optical film such as an LR (Low Reflective) polarizing plate or an AG (Anti Glare) -LR polarizing plate, the surface of the optical film is subjected to an antifouling treatment with a silicone compound or a fluorine compound. When the surface protective film used for the optical film is peeled from the optical film as the adherend, the peeling voltage is high.

  Moreover, when the polyether modified silicone is mixed in the adhesive layer of patent document 5, 6, it is difficult to finely adjust the adhesive force of a surface protection film. Moreover, since the polyether modified silicone is mixed in the pressure-sensitive adhesive layer, when the conditions for applying and drying the pressure-sensitive adhesive composition on the base film change, the pressure-sensitive adhesive layer on which the surface protective film was formed The characteristics of the surface change slightly. Furthermore, from the viewpoint of protecting the surface of the optical film, the thickness of the pressure-sensitive adhesive layer can not be made extremely thin. Therefore, according to the thickness of the pressure-sensitive adhesive layer, it is necessary to increase the addition amount of the polyether modified silicone mixed in the pressure-sensitive adhesive layer, and as a result, the adherend surface is easily contaminated, and the adhesive strength over time Contamination of the adherend changes.

  In recent years, with the spread of 3D displays (stereoscopic displays), there is one in which an FPR (Film Patterned Retarder) film is bonded to the surface of an optical film such as a polarizing plate. After peeling off the surface protection film bonded to the surface of the optical film such as a polarizing plate, the FPR film is bonded. However, if the surface of the optical film such as a polarizing plate is contaminated with the pressure-sensitive adhesive or antistatic agent used for the surface protective film, there is a problem that the FPR film is difficult to adhere. For this reason, the surface protection film used for the said application is required for the thing with little contamination with respect to a to-be-adhered body.

  On the other hand, in some liquid crystal panel manufacturers, the surface protective film bonded to an optical film such as a polarizing plate is peeled off once and mixed with air bubbles as a method for evaluating the contamination of the surface protective film to the adherend. The method of heat-processing what was re-bonded in a fixed state on predetermined conditions, and peeling off a surface protection film after that and observing the surface of a to-be-adhered body is employ | adopted. In such an evaluation method, even if the surface contamination of the adherend is very small, the difference in the surface contamination of the adherend between the portion mixed with air bubbles and the portion in contact with the adhesive of the surface protective film. Will remain as air bubble marks (sometimes called air bubbles). Therefore, it becomes a very severe evaluation method as an evaluation method of the contamination nature to the surface of a to-be-adhered body. In recent years, there has been a demand for a surface protection film having no problem in the contamination of the surface of an adherend even as a result of determination by such a severe evaluation method. However, in the surface protection film using the pressure-sensitive adhesive layer containing an antistatic agent, which has been conventionally proposed, it has been difficult to solve the problem.

  For this reason, there is a need for a surface protection film for use in an optical film, which has very little contamination to the adherend and does not change with time the contamination of the adherend. Furthermore, there is a demand for a surface protection film in which the peeling charging voltage when peeling from an adherend is suppressed low.

The present inventors diligently studied to solve this problem.
In order to reduce the contamination on the adherend and to reduce the time-dependent change of the antistatic performance, it is necessary to reduce the addition amount of the antistatic agent presumed to be the cause of the contamination of the adherend. However, when the amount of addition of the antistatic agent is decreased, the peeling charging voltage is increased when the surface protective film is peeled from the adherend. The inventors of the present invention examined a method for suppressing the peeling voltage drop when peeling the surface protection film from the adherend without increasing the absolute amount of the addition amount of the antistatic agent. As a result, the antistatic agent is not added and mixed in the pressure-sensitive adhesive composition to form the pressure-sensitive adhesive layer, but after the pressure-sensitive adhesive composition is applied and dried to laminate the pressure-sensitive adhesive layer, the pressure-sensitive adhesive The present invention has been found that, by applying an appropriate amount of an antistatic agent component to the surface of a layer, it is possible to suppress the peeling charge voltage low when peeling a surface protection film from an optical film as an adherend. Completed.

  The present invention has been made in view of the above circumstances, and is a method for producing an antistatic surface protective film having little peeling contamination to an adherend and having excellent peeling antistatic performance without deteriorating with time, and charging. It is an object of the present invention to provide a protective surface protection film.

  In order to solve the above problems, the antistatic surface protective film of the present invention is applied and dried on the pressure-sensitive adhesive composition to laminate the pressure-sensitive adhesive layer, and then a liquid at an appropriate amount of 20 ° C. on the surface of the pressure-sensitive adhesive layer. In addition to suppressing the contamination of the adherend to a low level by applying the silicone compound and the antistatic agent of the present invention, the technical idea is to suppress the release voltage when peeling off from the optical film as the adherend. There is.

In order to solve the above problems, in the present invention , an adhesive layer is formed on one side of a base film made of a resin having transparency, and an antistatic agent is transferred to the surface of the adhesive layer. A method for producing an antistatic surface protection film, wherein the pressure-sensitive adhesive layer comprises an acrylic polymer, (D) a bifunctional or higher isocyanate compound, (E) a crosslinking accelerator, and (F) keto enol tautomerism. A pressure-sensitive adhesive layer obtained by crosslinking a pressure-sensitive adhesive composition containing a body compound, wherein the acrylic polymer is selected from the group consisting of (A) alkyl group having at least C4 to C18 (meth) acrylic acid ester monomer and one co as monomers group, (B) copolymerizable with monomers containing a hydroxyl group, (C) a hydroxyl group or nitrogen-containing vinyl monomer not containing an alkoxy group-containing alkyl Meth) acrylate monomer and at least one and, an acrylic polymer obtained by copolymerizing selected from among copolymerizable monomers group consisting of the (E) the relative crosslinking accelerator (F) ketoenols each other The weight ratio of (E) :( F) is 1:80 to 1: 500 as the ratio of the mutagen compound, and a release agent layer containing an antistatic agent is laminated on one side of the resin film, the release agent layer, and a release agent composed mainly of dimethyl polysiloxane, and silicone compounds liquid at 20 ° C., the release film ing is formed of a resin composition containing an antistatic agent, a release agent After bonding to the surface of the pressure-sensitive adhesive layer through a layer, the release film is peeled off from the surface of the pressure-sensitive adhesive layer, and the silicone-based release agent layer is formed only on the surface of the pressure-sensitive adhesive layer. Provided is a method for producing an antistatic surface protective film, which comprises transferring a compound and the above-mentioned antistatic agent.

  Moreover, it is preferable that the (G) polyalkylene glycol mono (meth) acrylic acid ester monomer is further contained as said copolymerizable monomer group.

  The (E) crosslinking accelerator is preferably at least one selected from the group consisting of aluminum chelate compounds, titanium chelate compounds, and iron chelate compounds.

  Further, the copolymerizable monomer containing a hydroxyl group (B) is 8-hydroxyoctyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate It is preferable that it is at least 1 or more types selected from the compound group which consists of an acrylate, N-hydroxy (meth) acrylamide, N- hydroxymethyl (meth) acrylamide, N- hydroxyethyl (meth) acrylamide.

  In addition, the (G) polyalkylene glycol mono (meth) acrylic acid ester monomer is selected from polyalkylene glycol mono (meth) acrylates, methoxypolyalkylene glycol (meth) acrylates, and ethoxy polyalkylene glycol (meth) acrylates. Preferably, it is at least one or more.

  Further, as the (D) bifunctional or higher isocyanate compound, the bifunctional isocyanate compound is a compound produced by reacting a diisocyanate compound and a diol compound with an acyclic aliphatic isocyanate compound, and as a diisocyanate compound Is an aliphatic diisocyanate, which is a compound selected from the group consisting of tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate and 2-methyl-1 as a diol compound , 3-propanediol, 2,2-dimethyl-1,3-propanediol, 2-methyl-2-propyl-1,3-propanediol, 2-ethyl-2-butyl-1,3-propane And one selected from the group consisting of: 3-methyl-1,5-pentanediol, 2,2-dimethyl-1,3-propanediol monohydroxypivalate, polyethylene glycol, polypropylene glycol, 3 As functional isocyanate compounds, isocyanurates of hexamethylene diisocyanate, isocyanurates of isophorone diisocyanate, adducts of hexamethylene diisocyanate, adducts of isophorone diisocyanate, adducts of hexamethylene diisocyanate, buret of hexamethylene diisocyanate, isophorone diisocyanate Bullet body, isocyanurate of tolylene diisocyanate compound, isocyanurate of xylylene diisocyanate compound, hydrogenated Isocyanurate of Siri diisocyanate compound, adduct of tolylene diisocyanate compound, adduct of xylylene diisocyanate compounds, adducts of hydrogenated xylylene diisocyanate compound, it is preferably made of.

  Moreover, it is preferable that the said adhesive composition contains (H) polyether modified siloxane compound whose HLB value is 7-15.

  Moreover, it is preferable that the silicone type compound in the said release agent layer is polyether modified silicone.

  Further, the antistatic agent in the release agent layer is preferably an alkali metal salt.

  Moreover, in order to solve said subject, the carbon number of the (A) alkyl group is a C4-C18 (meth) acrylic acid ester monomer on the single side | surface of the base film which consists of resin which has transparency. (B) A copolymerizable monomer containing a hydroxyl group, and (C) a nitrogen containing no hydroxyl group, which does not contain at least one copolymerizable monomer containing a carboxyl group as a copolymerizable monomer group Acrylics comprising a copolymer obtained by copolymerizing at least one selected from the group of copolymerizable monomers consisting of a vinyl-containing monomer or an alkoxy group-containing alkyl (meth) acrylate monomer not containing a hydroxyl group A polymer, (D) an isocyanate compound having two or more functional groups, (E) a crosslinking accelerator, and (F) a keto enol tautomer compound And a pressure-sensitive adhesive layer formed by crosslinking a pressure-sensitive adhesive composition, and a release film in which a release agent layer containing an antistatic agent is laminated on one surface of a resin film on the surface of the pressure-sensitive adhesive layer. A resin composition comprising: a release agent layer, and the release agent layer containing a release agent containing dimethylpolysiloxane as a main component, a silicone compound which is liquid at 20 ° C., and an antistatic agent. The silicone-based compound and the antistatic agent of the release layer are transferred only to the surface of the pressure-sensitive adhesive layer, and the (E) keto-enol The antistatic surface protection film is characterized in that the weight ratio of (E) :( F) is 1:80 to 1: 500 as a ratio of the mutant compound.

  Moreover, it is preferable that the (G) polyalkylene glycol mono (meth) acrylic acid ester monomer is further contained as said copolymerizable monomer group.

  Moreover, it is preferable that the silicone type compound in the said release agent layer is polyether modified silicone.

  Further, the antistatic agent in the release agent layer is preferably an alkali metal salt.

  The present invention also provides an optical film formed by laminating the above-described antistatic surface protective film.

  The present invention also provides an optical component formed by laminating the above-described antistatic surface protective film.

The antistatic surface protective film of the present invention causes little contamination to the adherend, and the low contamination to the adherend does not change with time. Further, according to the present invention, even when the surface of an adherend such as an LR polarizing plate or an AG-LR polarizing plate is an anti-pollution film treated with a silicone compound or a fluorine compound, etc. It is possible to suppress the peeling charging voltage generated when peeling the surface protective film from the adherend to a low level, and to provide an antistatic surface protective film having excellent peeling antistatic performance without deterioration with time.
According to the antistatic surface protective film of the present invention, since the surface of the optical film can be protected with certainty, productivity and yield can be improved.

It is sectional drawing which showed the concept of the antistatic surface protective film of this invention. It is sectional drawing which shows the state which peeled off the peeling film from the antistatic surface protective film of this invention. FIG. 2 is a cross-sectional view of one of the embodiments of the optical component of the present invention.

Hereinafter, the present invention will be described in detail based on the embodiments.
FIG. 1 is a cross-sectional view showing the concept of the antistatic surface protective film of the present invention. In the antistatic surface protective film 10, an adhesive layer 2 is formed on the surface of one side of a transparent base film 1. The release film 5 in which the release agent layer 4 is formed on the surface of the resin film 3 is bonded to the surface of the pressure-sensitive adhesive layer 2.

As the base film 1 used for the antistatic surface protection film 10 according to the present invention, a base film made of a resin having transparency and flexibility is used. Thereby, the appearance inspection of an optical component can be performed in the state which bonded the antistatic surface protection film to the optical component which is a to-be-adhered body. The film made of a resin having transparency used as the base film 1 is preferably a polyester film of polyethylene terephthalate, polyethylene naphthalate, polyethylene isophthalate, polybutylene terephthalate or the like. Besides polyester films, films made of other resins may be used as long as they have the required strength and optical suitability. The base film 1 may be a non-oriented film or a uniaxially or biaxially stretched film. In addition, the draw ratio of the drawn film or the orientation angle of the axial method formed along with the crystallization of the drawn film may be controlled to a specific value.
The thickness of the base film 1 used for the antistatic surface protective film 10 according to the present invention is not particularly limited, but for example, a thickness of about 12 to 100 μm is preferable, and a thickness of about 20 to 50 μm is easy to handle , More preferred.
In addition, on the surface of the base film 1 opposite to the surface on which the pressure-sensitive adhesive layer 2 is formed, an antifouling layer for preventing surface contamination, an antistatic layer, a scratch-resistant hard coat layer, etc. may be used. It can be provided. In addition, the surface of the base film 1 may be subjected to easy adhesion treatment such as surface modification by corona discharge and application of an anchor coating agent.

  In addition, the pressure-sensitive adhesive layer 2 used in the antistatic surface protective film 10 according to the present invention adheres to the surface of the adherend, can be easily peeled off after use, and does not easily contaminate the adherend. It is not particularly limited as long as it is, but in consideration of durability after bonding to an optical film, it is common to use an acrylic pressure-sensitive adhesive formed by crosslinking a (meth) acrylate copolymer. .

In particular, the main agent of the acrylic adhesive contains a carboxyl group as a monomer group copolymerizable with at least one of (A) alkyl group (C4 to C18) (meth) acrylic acid ester monomer A copolymer comprising (B) a hydroxyl group-containing copolymerizable monomer which does not contain a polymerizable monomer, and (C) a hydroxyl group-free nitrogen-containing vinyl monomer or an alkoxy group-containing alkyl (meth) acrylate monomer An adhesive layer comprising an acrylic polymer of a copolymer of at least one selected from the group of possible monomers is preferred.
As the above-mentioned copolymerizable monomer group, (G) polyalkylene glycol mono (meth) acrylic acid ester monomer can be further included.
Furthermore, an adhesion comprising an adhesive composition comprising (D) a bifunctional or higher functional isocyanate compound, (E) a crosslinking accelerator, and (F) a ketoenol tautomer compound in addition to the acrylic polymer. Agent layer is preferred.

(A) As the (meth) acrylic acid ester monomer having a C4 to C18 carbon number of the alkyl group, butyl (meth) acrylate, isobutyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate (Meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl Meta) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadedecyl (Meth) acrylate, octadecyl (meth) acrylate, myristyl (meth) acrylate, isomyristyl (meth) acrylate, cetyl (meth) acrylate, isocetyl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, etc. Can be mentioned.
When the total amount of the acrylic polymer of the copolymer is 100 parts by weight, the (A) alkyl group contains 50 to 95 parts by weight of (meth) acrylic acid ester monomer having C4 to C18 carbon number Is preferred.

(B) As a copolymerizable monomer containing a hydroxyl group, 8-hydroxyoctyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate And hydroxy-containing (meth) acrylamides such as N-hydroxy (meth) acrylamide, N-hydroxymethyl (meth) acrylamide, N-hydroxyethyl (meth) acrylamide and the like.
8-hydroxyoctyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, N-hydroxy (meth) acrylamide, N-hydroxymethyl (meth) It is preferable that it is at least 1 type or more selected from the compound group which consists of acrylamide and N-hydroxyethyl (meth) acrylamide.
When the total amount of the acrylic polymer of the copolymer is 100 parts by weight, it is preferable that the copolymerizable monomer having a hydroxyl group (B) is contained in a ratio of 0.1 to 10 parts by weight.

  It is preferable that the said acryl-type polymer contains at least 1 or more types of the nitrogen-containing vinyl monomer which does not contain the (C) hydroxyl group, or the alkoxy-group containing alkyl (meth) acrylate monomer as said copolymerizable monomer group.

  Among (C), as the (C-1) nitrogen-containing vinyl monomer, a vinyl monomer containing an amide bond, a vinyl monomer containing an amino group, a vinyl monomer having a nitrogen-containing heterocyclic structure and the like can be mentioned. More specifically, N-vinyl-2-pyrrolidone, N-vinyl pyrrolidone, methyl vinyl pyrrolidone, N-vinyl pyridine, N-vinyl piperidone, N-vinyl pyrimidine, N-vinyl piperazine, N-vinyl pyrazine, N-vinyl Cyclic nitrogen vinyl compounds having an N-vinyl-substituted heterocyclic structure such as pyrrole, N-vinylimidazole, N-vinyloxazole, N-vinylmorpholine, N-vinylcaprolactam, N-vinyl lauryl lactam; Meth) acryloyl morpholine, N- (meth) acryloyl piperazine, N- (meth) acryloyl aziridine, N- (meth) acryloyl azetidine, N- (meth) acryloyl pyrrolidine, N- (meth) acryloyl piperidine, N- (meth) ) Acryloyl azepane, N-(Meta) a Cyclic nitrogen vinyl compounds having an N- (meth) acryloyl-substituted heterocyclic structure such as lyoylazocan; and heterocyclic rings having a nitrogen atom and an ethylenically unsaturated bond such as N-cyclohexyl maleimide, N-phenyl maleimide, etc. in the ring Cyclic nitrogen vinyl compounds having a formula structure; unsubstituted or monoalkyl-substituted (meth) acrylamides such as (meth) acrylamide, N-methyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N-t-butyl (meth) acrylamide ) Acrylamide; N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N, N-dipropyl acrylamide, N, N-diisopropyl (meth) acrylamide, N, N-dibutyl (meth) acrylamide , N-ethyl-N-methyl (meth) group N-methyl-N-propyl (meth) acrylamide, N-methyl-N-isopropyl (meth) acrylamide and like dialkyl substituted (meth) acrylamides; N, N-dimethylaminomethyl (meth) acrylate, N, N- Dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, N, N-dimethylaminoisopropyl (meth) acrylate, N, N-dimethylaminobutyl (meth) acrylate, N, N-diethylaminomethyl (Meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N-ethyl-N-methylaminoethyl (meth) acrylate, N-methyl-N-propylaminoethyl (meth) acrylate, N-methyl-N- Isopropylaminoethyl Ta) Dialkylamino (meth) acrylates such as acrylate, N, N-dibutylaminoethyl (meth) acrylate, t-butylaminoethyl (meth) acrylate, etc .; N, N-dimethylaminopropyl (meth) acrylamide, N, N- Diethylaminopropyl (meth) acrylamide, N, N-dipropylaminopropyl (meth) acrylamide, N, N-diisopropylaminopropyl (meth) acrylamide, N-ethyl-N-methylaminopropyl (meth) acrylamide, N-methyl- N, N-dialkyl substituted aminopropyl (meth) acrylamides such as N-propylaminopropyl (meth) acrylamide, N-methyl-N-isopropylaminopropyl (meth) acrylamide and the like; N-vinylformamide, N-vinylaceto , N-vinylcarboxylic acid amides such as N-vinyl-N-methylacetamide; N-methoxymethyl (meth) acrylamide, N-ethoxyethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, diacetone acrylamide And (meth) acrylamides such as N, N-methylenebis (meth) acrylamide; unsaturated carboxylic acid nitriles such as (meth) acrylonitrile; and the like.

  As the (C-1) nitrogen-containing vinyl monomer, one not containing a hydroxyl group is preferable, and one containing no hydroxyl group and a carboxyl group is more preferable. As such a monomer, monomers exemplified above, for example, acrylic monomers containing N, N-dialkyl-substituted amino group or N, N-dialkyl-substituted amido group; N-vinyl-2-pyrrolidone, N-vinyl N-vinyl-substituted lactams such as caprolactam and N-vinyl-2-piperidone; N- (meth) acryloyl-substituted cyclic amines such as N- (meth) acryloyl morpholine and N- (meth) acryloyl pyrrolidine are preferable.

Among (C), as the (C-2) alkoxy group-containing alkyl (meth) acrylate monomer, 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2-propoxyethyl (meth) acrylate, 2-isopropoxyethyl (meth) acrylate, 2-butoxyethyl (meth) acrylate, 2-methoxypropyl (meth) acrylate, 2-ethoxypropyl (meth) acrylate, 2-propoxypropyl (meth) acrylate, 2-isopropoxy Propyl (meth) acrylate, 2-butoxypropyl (meth) acrylate, 3-methoxypropyl (meth) acrylate, 3-ethoxypropyl (meth) acrylate, 3-propoxypropyl (meth) acrylate, 3-isopropoxypropyl Meta) acrylate, 3-butoxypropyl (meth) acrylate, 4-methoxybutyl (meth) acrylate, 4-ethoxybutyl (meth) acrylate, 4-propoxybutyl (meth) acrylate, 4-isopropoxybutyl (meth) acrylate, 4-butoxybutyl (meth) acrylate etc. are mentioned.
These alkoxy group-containing alkyl (meth) acrylate monomers have a structure in which an atom of the alkyl group in the alkyl (meth) acrylate is substituted with an alkoxy group.

  When the total amount of the acrylic polymer of the copolymer is 100 parts by weight, 0 to 20 weight of the (C-1) hydroxyl group-free nitrogen-containing vinyl monomer or the (C-2) alkoxy group-containing alkyl (meth) acrylate monomer It is preferable to contain in the ratio of part. The nitrogen-containing vinyl monomer (C-1) having no hydroxyl group and the (C-2) alkoxy group-containing alkyl (meth) acrylate monomer may be used alone or in combination of two or more. In the pressure-sensitive adhesive layer according to the present invention, the pressure-sensitive adhesive composition may not contain (C) a hydroxyl group-free nitrogen-containing vinyl monomer or an alkoxy group-containing alkyl (meth) acrylate monomer.

(D) The bifunctional or higher functional isocyanate compound may be at least one or more selected from polyisocyanate compounds having at least two or more isocyanate (NCO) groups in one molecule. The polyisocyanate compounds may be classified into aliphatic isocyanates, aromatic isocyanates, acyclic isocyanates, alicyclic isocyanates and the like, but any of them may be used. Specific examples of the polyisocyanate compound include aliphatic isocyanate compounds such as hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), trimethylhexamethylene diisocyanate (TMDI), diphenylmethane diisocyanate (MDI), xylylene diisocyanate (XDI) And aromatic isocyanate compounds such as hydrogenated xylylene diisocyanate (H6XDI), dimethyldiphenylene diisocyanate (TOID) and tolylene diisocyanate (TDI).
The trifunctional or higher isocyanate compound is a biuret-modified or isocyanurate-modified product of a bifunctional isocyanate compound (a compound having two NCO groups in one molecule), and a trivalent or higher such as trimethylolpropane (TMP) or glycerin. And adducts thereof (polyol-modified products) with the above-mentioned polyols (compounds having at least 3 or more OH groups in one molecule).
It is also possible to use only the (D-1) trifunctional isocyanate compound or the (D-2) bifunctional isocyanate compound as the (D) bifunctional or higher functional isocyanate compound. Moreover, it is also possible to use together (D-1) trifunctional isocyanate compound and (D-2) bifunctional isocyanate compound.

  Furthermore, as the (D-1) trifunctional isocyanate compound used in the present invention, isocyanurate of hexamethylene diisocyanate compound, isocyanurate of isophorone diisocyanate compound, adduct of hexamethylene diisocyanate compound, adduct of isophorone diisocyanate compound, (D-1-1) At least one or more selected from the first aliphatic isocyanate compound group consisting of a biuret of hexamethylene diisocyanate compound and a biuret of isophorone diisocyanate compound, and tolylene diisocyanate compound Of isocyanurate, isocyanurate of xylylene diisocyanate compound, isocyanurate of hydrogenated xylylene diisocyanate compound, tolylene diisocyanate (D-1-2) A second aromatic isocyanate compound group comprising an adduct of a compound, an adduct of a xylylene diisocyanate compound, and an adduct of a hydrogenated xylylene diisocyanate compound; It is preferable to include at least one or more. It is preferable to use the (D-1-1) first aliphatic isocyanate compound group and the (D-1-2) second aromatic isocyanate compound group in combination. In the present invention, as the (D-1) trifunctional isocyanate compound, at least one or more selected from (D-1-1) first aliphatic isocyanate compounds, (D-1-2) The adhesion balance of the low-speed peeling area and the high-speed peeling area can be further improved by using at least one or more selected from the second aromatic isocyanate compound group in combination.

  In addition, the (D-1) trifunctional isocyanate compound is at least one or more selected from the (D-1-1) first aliphatic isocyanate compound group, and the above (D-1-2) ) Containing at least one or more selected from the second aromatic isocyanate compounds, and including 0.5 to 5.0 parts by weight in total with respect to 100 parts by weight of the copolymer Is preferred. Further, among the (D-1-2) first aliphatic isocyanate compounds and at least one or more selected from the (D-1-2) second aromatic isocyanates. (D-1-1) :( D-1-2) is in the range of 10%: 90% to 90%: 10% by weight ratio as the mixing ratio with at least one or more selected from Is preferred.

Furthermore, the (D-2) bifunctional isocyanate compound used in the present invention is preferably a compound produced by reacting a diisocyanate compound and a diol compound with an acyclic aliphatic isocyanate compound.
For example, a diisocyanate compound having the general formula "O = CCN-X-N = C = O" (where X is a divalent group), and a general formula "HO-Y-OH" (where Y is a divalent group) As a compound produced | generated by making a diisocyanate compound and a diol compound react when it represents a diol compound, the compound represented by the following general formula Z is mentioned, for example.

[General formula Z]
O = C = N-X- (NH-CO-O-Y-O-CO-NH-X) _n- N = C = O

  Here, n is an integer of 0 or more. When n is 0, the general formula Z represents "O = C = N-X-N = C = O". Although a bifunctional acyclic aliphatic isocyanate compound may contain a compound of general formula Z where n is 0 (diisocyanate compound unreacted with respect to the diol compound), a compound in which n is an integer of 1 or more is an essential component. Is preferably contained. The difunctional acyclic aliphatic isocyanate compound may be a mixture of a plurality of compounds in which n in the general formula Z is different.

  The diisocyanate compound represented by the general formula "O = C = N-X-N = C = O" is an aliphatic diisocyanate. It is preferable that X is acyclic and aliphatic divalent group. The aliphatic diisocyanate preferably comprises one or more selected from the group consisting of tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, and lysine diisocyanate.

  The diol compound represented by the general formula "HO-Y-OH" is an aliphatic diol. Y is preferably an acyclic and aliphatic divalent group. Examples of the diol compound include 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 2-methyl-2-propyl-1,3-propanediol, and 2-ethyl-2 -Compounds selected from the group consisting of -butyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2,2-dimethyl-1,3-propanediol monohydroxypivalate, polyethylene glycol and polypropylene glycol It is preferable to consist of one or two or more selected.

  The weight ratio (D-1 / D-2) of the (D-1) trifunctional isocyanate compound to the (D-2) bifunctional isocyanate compound is preferably 1 to 90. It is preferable that the said (D) bifunctional or more than trifunctional isocyanate compound is 0.1-10 weight part with respect to 100 weight part of said acrylic polymers.

  (E) The crosslinking accelerator may be a substance that functions as a catalyst for the reaction (crosslinking reaction) between the copolymer and the crosslinking agent when using a polyisocyanate compound as the crosslinking agent, and a tertiary amine And organic metal compounds such as metal chelate compounds, organic tin compounds, organic lead compounds, organic zinc compounds and the like. In the present invention, metal chelate compounds and organic tin compounds are preferable as the crosslinking accelerator.

The metal chelate compound is a compound in which one or more polydentate ligands L are bonded to a central metal atom M. The metal chelate compound may or may not have one or more monodentate ligands X bonded to the metal atom M. For example, when a metal chelate compound having one metal atom M is represented by M (L) _m (X) _n , m ≧ 1 and n ≧ 0. When m is 2 or more, m L may be the same ligand or different ligands. When n is 2 or more, n X may be the same ligand or different ligands.

Examples of the metal atom M include Fe, Ni, Mn, Cr, V, Ti, Ru, Zn, Al, Zr, Sn and the like.
As polydentate ligand L, β-keto esters such as methyl acetoacetate, ethyl acetoacetate, octyl acetoacetate, oleyl acetoacetate, lauryl acetoacetate, stearyl acetoacetate, and acetylacetone (also known as 2,4-pentanedione), Examples include β-diketones such as 2,4-hexanedione and benzoylacetone. These are keto-enol tautomeric compounds and in the case of polydentate ligands L may be enolates (eg acetylacetonate) in which the enol is deprotonated.
Examples of the monodentate ligand X include halogen atoms such as chlorine atom and bromine atom, pentanoyl group, hexanoyl group, 2-ethylhexanoyl group, octanoyl group, nonanoyl group, decanoyl group, dodecanoyl group, octadecanoyl group, etc. And alkoxy groups such as methoxy group, ethoxy group, n-propoxy group, isopropoxy group and butoxy group.

  Specific examples of metal chelate compounds include tris (2,4-pentanedionato) iron (III), iron trisacetylacetonate, titanium trisacetylacetonate, ruthenium trisacetylacetonate, zinc bis acetylacetonate, aluminum tris Acetylacetonate, zirconium tetrakis acetylacetonate, tris (2,4-hexanedionato) iron (III), bis (2,4-hexanedionato) zinc, tris (2,4-hexanedionato) titanium, tris Examples include (2,4-hexanedionato) aluminum, tetrakis (2,4-hexanedionato) zirconium and the like.

Examples of the organic tin compound include dialkyl tin oxide, fatty acid salts of dialkyl tin, and fatty acid salts of stannous tin. Conventionally, dibutyltin compounds have been widely used, but in recent years, the problem of toxicity of organotin compounds has been pointed out, and in particular, tributyltin (TBT) contained in dibutyltin compounds is also concerned as an endocrine disrupting substance. From the viewpoint of safety, long-chain alkyl tin compounds such as dioctyl tin compounds are preferred. Specific examples of organotin compounds include dioctyltin oxide and dioctyltin dilaurate. Although Sn compounds can also be used tentatively, in view of the trend where the use of more safe substances is required in the future, Al, Ti, Fe, etc. are safer than Sn. It is preferred to use metal chelate compounds.
The (E) crosslinking accelerator in the pressure-sensitive adhesive composition according to the present invention is preferably at least one selected from the group consisting of an aluminum chelate compound, a titanium chelate compound, and an iron chelate compound.
The amount of the crosslinking accelerator (E) is preferably 0.001 to 0.5 parts by weight with respect to 100 parts by weight of the copolymer.

(F) As the keto-enol tautomer compound, β-keto esters such as methyl acetoacetate, ethyl acetoacetate, octyl acetoacetate, oleyl acetoacetate, lauryl acetoacetate, stearyl acetoacetate, acetylacetone, 2,4-hexanedione And β-diketones such as benzoylacetone. In the pressure-sensitive adhesive composition having a polyisocyanate compound as a crosslinking agent, these block the isocyanate group possessed by the crosslinking agent to suppress an excessive increase in viscosity and gelation of the pressure-sensitive adhesive composition after blending of the crosslinking agent. The pot life of the pressure-sensitive adhesive composition can be extended.
The keto-enol tautomer compound (F) is preferably contained in an amount of 0.1 to 200 parts by weight with respect to 100 parts by weight of the copolymer.

  (F) The ratio of (F) keto enol tautomer compound to (E) crosslinking accelerator because (F) keto enol tautomer compound has the effect of suppressing crosslinking in contrast to (E) crosslinking accelerator Is preferably set appropriately. In order to prolong the pot life of the pressure-sensitive adhesive composition and improve the storage stability, the weight ratio of (E) :( F) is preferably in the range of 1: 1 to 1: 500, and more preferably 1:30 to 1: 500, and most preferably 1:80 to 1: 500.

The acrylic polymer can optionally further contain (G) a polyalkylene glycol mono (meth) acrylic acid ester monomer as the copolymerizable monomer group. (G) The polyalkylene glycol mono (meth) acrylic acid ester monomer may be a compound in which one hydroxyl group is esterified as a (meth) acrylic acid ester among a plurality of hydroxyl groups possessed by the polyalkylene glycol. Since the (meth) acrylic ester group becomes a polymerizable group, it can be copolymerized with the main agent polymer. The other hydroxyl group may be OH as it is, and may be an alkyl ether such as methyl ether or ethyl ether, or a saturated carboxylic acid ester such as acetic acid ester.
As an alkylene group which polyalkylene glycol has, although an ethylene group, a propylene group, a butylene group etc. are mentioned, it is not limited to these. The polyalkylene glycol may be a copolymer of two or more polyalkylene glycols such as polyethylene glycol, polypropylene glycol and polybutylene glycol. Examples of the polyalkylene glycol copolymer include polyethylene glycol-polypropylene glycol, polyethylene glycol-polybutylene glycol, polypropylene glycol-polybutylene glycol, polyethylene glycol-polypropylene glycol-polybutylene glycol and the like, and the copolymer is It may be a block copolymer or a random copolymer.
(G) It is preferable that the average repetition number of the alkylene oxide which a polyalkylene glycol mono (meth) acrylic acid ester monomer comprises a polyalkylene glycol chain is 3-14. The “average number of repetitions of alkylene oxide” is the average number of repeating alkylene oxide units in the “polyalkylene glycol chain” portion included in the molecular structure of (G) polyalkylene glycol mono (meth) acrylic acid ester monomer is there.

(G) The polyalkylene glycol mono (meth) acrylate monomer is selected from polyalkylene glycol mono (meth) acrylates, methoxypolyalkylene glycol (meth) acrylates, and ethoxy polyalkylene glycol (meth) acrylates. It is preferable that it is at least one or more.
More specifically, polyethylene glycol-mono (meth) acrylate, polypropylene glycol-mono (meth) acrylate, polybutylene glycol-mono (meth) acrylate, polyethylene glycol-polypropylene glycol-mono (meth) acrylate, polyethylene glycol-poly Butylene glycol-mono (meth) acrylate, polypropylene glycol-polybutylene glycol-mono (meth) acrylate, polyethylene glycol-polypropylene glycol-polybutylene glycol-mono (meth) acrylate; methoxypolyethylene glycol- (meth) acrylate, methoxypolypropylene glycol -(Meth) acrylate, methoxy polybutylene glycol-(meth) acrylate, methoxy Polyethylene glycol-polypropylene glycol- (meth) acrylate, methoxy-polyethylene glycol-polybutylene glycol- (meth) acrylate, methoxy-polypropylene glycol-polybutylene glycol- (meth) acrylate, methoxy-polyethylene glycol-polypropylene glycol-polybutylene glycol -(Meth) acrylate; ethoxy polyethylene glycol-(meth) acrylate, ethoxy polypropylene glycol (meth) acrylate, ethoxy polybutylene glycol (meth) acrylate, ethoxy-polyethylene glycol-polypropylene glycol-(meth) acrylate, ethoxy-polyethylene Glycol-polybutylene glycol- (meth) acrylate Ethoxy - polypropylene glycol - polybutylene glycol - (meth) acrylate, ethoxy - polyethylene glycol - polypropylene glycol - polybutylene glycol - such as (meth) acrylate.
When the total amount of the acrylic polymer of the copolymer is 100 parts by weight, it is preferable that the (G) polyalkylene glycol mono (meth) acrylic acid ester monomer is contained in a ratio of 0 to 50 parts by weight. In the pressure-sensitive adhesive layer according to the present invention, the pressure-sensitive adhesive composition may not contain the (G) polyalkylene glycol mono (meth) acrylic acid ester monomer.

The pressure-sensitive adhesive composition can optionally contain (H) a polyether-modified siloxane compound. (H) a polyether-modified siloxane compound is a siloxane compound having a polyether group, in addition to the normal siloxane units [-SiR ¹ ₂ -O-], siloxane units having polyether groups [-SiR ¹ (R having _{^{2 O (R 3 O) n}} R 4) -O- ]. Here, R ¹ represents one or more alkyl groups or aryl groups, R ² and R ³ represent one or more alkylene groups, R ⁴ represents one or more alkyl groups or an acyl group Etc. (terminal group). Polyether group includes polyoxyalkylene groups such as polyoxyethylene group [(C ₂ H ₄ O) _n ] and polyoxypropylene group [(C ₃ H ₆ O) _n ].

The (H) polyether modified siloxane compound is preferably a polyether modified siloxane compound having an HLB value of 7 to 15. Further, it is preferable that 0.01 to 1.0 parts by weight of the (H) polyether-modified siloxane compound is contained with respect to 100 parts by weight of the copolymer. More preferably, it is 0.1 to 0.5 parts by weight.
HLB is, for example, a hydrophilic / lipophilic balance (hydrophilic / lipophilic ratio) defined in JIS K 3211 (term of surfactant) or the like.

(H) The polyether-modified siloxane compound can be obtained, for example, by grafting an organic compound having an unsaturated bond and a polyoxyalkylene group to a polyorganosiloxane main chain having a silicon hydride group by a hydrosilylation reaction. it can. Specifically, dimethylsiloxane methyl (polyoxyethylene) siloxane copolymer, dimethylsiloxane methyl (polyoxyethylene) siloxane methyl (polyoxypropylene) siloxane copolymer, dimethylsiloxane methyl (polyoxypropylene) A siloxane polymer etc. are mentioned.
The adhesion and rework performance of the pressure-sensitive adhesive can be improved by incorporating the (H) polyether-modified siloxane compound into the pressure-sensitive adhesive composition. If the pressure-sensitive adhesive composition does not contain a polyether-modified siloxane compound, the cost is lower.

  Furthermore, copolymerizable (meth) acrylic monomers containing alkylene oxide, (meth) acrylamide monomers, dialkyl substituted acrylamide monomers, surfactants, curing accelerators, plasticizers, fillers, curing retarders, and the like as other components Well-known additives such as processing aids, anti-aging agents and antioxidants can be appropriately blended. These may be used alone or in combination of two or more.

The main component copolymer used in the pressure-sensitive adhesive composition of the present invention has, as a monomer group copolymerizable with (A) an alkyl group, at least one of (C) -C18 (meth) acrylic acid ester monomers Selected from a group of copolymerizable monomers consisting of (B) a copolymerizable monomer containing a hydroxyl group, and (C) a nitrogen-containing vinyl monomer or an alkoxy group-containing alkyl (meth) acrylate monomer not containing a hydroxyl group It can synthesize | combine by copolymerizing at least 1 type and. As the copolymerizable monomer group, (G) a polyalkylene glycol mono (meth) acrylic acid ester monomer may be further included. The polymerization method of the copolymer is not particularly limited, and appropriate polymerization methods such as solution polymerization and emulsion polymerization can be used.
The pressure-sensitive adhesive composition of the present invention comprises the copolymer described above, (D) an isocyanate compound having two or more functional groups, (E) a crosslinking accelerator, and (F) a ketoenol tautomer compound, and further optionally any additive. It can be prepared by blending

It is preferable that the said copolymer is an acryl-type polymer, and it is preferable that 50-100 weight% of acryl-type monomers, such as a (meth) acrylic acid ester monomer and (meth) acrylic acid, (meth) acrylamides, are included.
When the acrylic polymer does not contain a copolymerizable monomer containing a carboxyl group as a copolymerizable monomer group, it is effective in improving the crosslinking speed and stabilizing the adhesive force. As a monomer which reacts with the (D) bifunctional or higher isocyanate compound used as a crosslinking agent, it is preferable to use a copolymerizable monomer containing a (B) hydroxyl group. As a preferable monomer composition of the said copolymer, 1 or more types respectively from said (A) and said (B), 1 type or more each from said (A), said (B), and said (C), One or more of each of A), (B), and (G), and one or more of each of (A), (B), (C), and (G) may be mentioned.

  The pressure-sensitive adhesive layer formed by crosslinking the pressure-sensitive adhesive composition has a tackiness of 0.05 to 0.1 N / 25 mm at a low peeling rate of 0.3 m / min and a high peeling rate of 30 m / min. The adhesive strength is preferably 1.0 N / 25 mm or less. This makes it possible to obtain a performance in which the adhesive strength is less changed even by the peeling speed, and it is possible to peel rapidly even by high-speed peeling. In addition, even when the surface protective film is once peeled off for re-sticking, it does not require an excessive force and is easily peeled off from the adherend.

The surface resistivity of the pressure-sensitive adhesive layer formed by crosslinking the pressure-sensitive adhesive composition is preferably 5.0 × 10 ⁺¹² Ω / □ or less, and the peeling voltage is preferably “± 0.6 kV or less”. In the present invention, “± 0.6 kV or less” means 0 to −0.6 kV and 0 to +0.6 kV, that is, −0.6 to +0.6 kV. If the surface resistivity is high, the ability to release static electricity generated by charging during peeling is inferior, so by making the surface resistivity sufficiently small, peeling caused by static electricity generated when the adherend peels off the pressure-sensitive adhesive layer The charged voltage is reduced, and it is possible to suppress the influence on the electric control circuit and the like of the adherend.

  The gel fraction of the pressure-sensitive adhesive layer (pressure-sensitive adhesive after crosslinking) formed by crosslinking the pressure-sensitive adhesive composition of the present invention is preferably 95 to 100%. Thus, by virtue of the high gel fraction, the adhesion does not become excessive at a low peeling speed, and the elution of unpolymerized monomers or oligomers from the copolymer is reduced, and reworkability and high temperature / high humidity are achieved. Durability is improved, and contamination of the adherend can be suppressed.

  The pressure-sensitive adhesive film of the present invention is obtained by forming a pressure-sensitive adhesive layer formed by crosslinking the pressure-sensitive adhesive composition of the present invention on one side or both sides of a resin film. Moreover, the surface protection film of this invention is a surface protection film formed by forming the adhesive layer formed by bridge | crosslinking the adhesive composition of this invention on the single side | surface of a resin film. The pressure-sensitive adhesive composition of the present invention has excellent antistatic performance since each of the components (A) to (F) is blended in a well-balanced manner, and at a low peeling speed and a high peeling speed, Excellent balance of adhesive strength, and also excellent in durability and rework performance (that there is no transfer of contamination on the adherend after tracing with a ballpoint pen on the surface protection film through the adhesive layer). Become. For this reason, it can be conveniently used as a use of the surface protection film of a polarizing plate.

  The thickness of the pressure-sensitive adhesive layer 2 used in the antistatic surface protective film 10 according to the present invention is not particularly limited, but preferably about 5 to 40 μm, more preferably about 10 to 30 μm. From the adherend, it is the pressure-sensitive adhesive layer 2 having a slight adhesive strength, in which the peel strength (adhesive force) of the antistatic surface protective film to the surface of the adherend is about 0.03 to 0.3 N / 25 mm. It is preferable from the thing which is excellent in the operativity at the time of peeling off antistatic surface protection film. Moreover, since it is excellent in the operativity at the time of peeling off the peeling film 5 from the antistatic surface protective film 10, it is preferable that the peeling force from the adhesive layer 2 of the peeling film 5 is 0.2 N / 50 mm or less.

  Further, the release film 5 used for the antistatic surface protective film 10 according to the present invention has a release agent containing dimethylpolysiloxane as a main component and a silicone compound which is liquid at 20 ° C. on one side of the resin film 3. A release agent layer 4 is formed using a resin composition containing an antistatic agent.

The resin film 3 may, for example, be a polyester film, a polyamide film, a polyethylene film, a polypropylene film or a polyimide film, but a polyester film is particularly preferable because of its excellent transparency and relatively low price. . The resin film may be a non-oriented film or a uniaxially or biaxially oriented film. In addition, the draw ratio of the drawn film or the orientation angle of the axial method formed along with the crystallization of the drawn film may be controlled to a specific value.
Although the thickness of the resin film 3 is not particularly limited, for example, a thickness of about 12 to 100 μm is preferable, and a thickness of about 20 to 50 μm is easy to handle and more preferable.
In addition, if necessary, the surface of the resin film 3 may be subjected to an easy adhesion treatment such as surface modification by corona discharge or application of an anchor coating agent.

  Examples of the release agent containing dimethylpolysiloxane as the main component of the release agent layer 4 include known silicone-based release agents such as addition reaction type, condensation reaction type, cationic polymerization type, and radical polymerization type. Products commercially available as addition reaction type silicone release agents include, for example, KS-776A, KS-847T, KS-779H, KS-837, KS-778, KS-830 (manufactured by Shin-Etsu Chemical Co., Ltd.) SRX-211, SRX-345, SRX-357, SD7333, SD7220, SD7223, LTC-300B, LTC-350G, LTC-310 (manufactured by Toray Dow Corning Co., Ltd.), and the like. As a product marketed as a condensation reaction type, SRX-290, SYLOFF-23 (Toray Dow Corning Co., Ltd. product) etc. are mentioned, for example. Products commercially available as cationic polymerization types include, for example, TPR-6501, TPR-6500, UV9300, VU9315, UV9430 (manufactured by Momentive Performance Materials), X62-7622 (manufactured by Shin-Etsu Chemical Co., Ltd.) And the like. As a product marketed as a radical polymerization type, X62-7205 (made by Shin-Etsu Chemical Co., Ltd.) etc. are mentioned, for example.

Examples of silicone-based compounds that are liquid at 20 ° C. that constitute the release agent layer 4 include polyether-modified silicones, alkyl-modified silicones and carbinol higher fatty acid ester-modified silicones. In the present invention, in order to improve the antistatic property of the surface of the pressure-sensitive adhesive layer, a silicone compound which is liquid at 20 ° C. in a compatible state is used in the release agent layer containing dimethylpolysiloxane as a main component. Be Among the modified silicone compounds, polyether modified silicones are preferred for use in the present invention. The polyether chain in the polyether modified silicone is composed of ethylene oxide, propylene oxide, etc. For example, by selecting the molecular weight of polyethylene oxide used for the side chain, physical properties such as compatibility with a silicone release agent, antistatic effect, etc. Is adjusted.
Further, products commercially available as polyether modified silicone include, for example, KF-351A, KF-352A, KF-353, KF-354L, KF-355A, KF-642 (manufactured by Shin-Etsu Chemical Co., Ltd.), SH8400, SH8700, SF8410 (manufactured by Toray Dow Corning Co., Ltd.), TSF-4440, TSF-4441, TSF-4445, TSF-4446, TSF-4450 (manufactured by Momentive Performance Materials), BYK-300, BYK -306, BYK-307, BYK-320, BYK-325, BYK-330 (manufactured by Bick Chemie), and the like.
The addition amount of the silicone compound liquid at 20 ° C. with respect to the release agent containing dimethylpolysiloxane as the main component varies depending on the type of silicone compound and the degree of compatibility with the release agent, but the antistatic surface protection film is adhered It may be set in consideration of the desired peeling charge voltage, the contamination property to the adherend, the adhesive property and the like when peeling from the above.

  The antistatic agent constituting the releasing agent layer 4 has good dispersibility in a releasing agent solution containing dimethylpolysiloxane as a main component, and inhibits the curing of the releasing agent containing dimethylpolysiloxane as a main component It is preferable not to An alkali metal salt is suitable as such an antistatic agent.

Examples of the alkali metal salt include metal salts consisting of lithium, sodium and potassium, and more specifically, for example, cations consisting of Li ⁺ , Na ⁺ and K ⁺ , Cl ⁻ , Br ⁻ , I ⁻ and BF ₄ ⁻ , PF ₆ ⁻ , SCN ⁻ , ClO ₄ ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , (C ₂ F ₅ SO ₂ ) ₂ N ⁻ , (CF ₃ SO ₂ ) ₃ C ⁻ Metal salts composed of anions are preferably used. Among them, LiBr, LiI, LiBF ₄ , LiPF ₆ , LiSCN, LiClO ₄ , LiCF ₃ SO ₃ , Li (CF ₃ SO ₂ ) ₂ N, Li (C ₂ F ₅ SO ₂ ) ₂ N, Li (CF _3). Lithium salts such as SO ₂ ) ₃ C are preferably used. These alkali metal salts may be used alone or in combination of two or more. In order to stabilize the ionic substance, a compound containing a polyoxyalkylene structure may be added.
The amount of the antistatic agent added to the release agent containing dimethylpolysiloxane as a main component varies depending on the type of the antistatic agent and the degree of affinity with the release agent, but when the antistatic surface protective film is peeled from the adherend It may be set in consideration of the desired peeling charge voltage, the contamination property to the adherend, the adhesive property and the like.

  There is no particular limitation on the method of mixing the release agent containing dimethylpolysiloxane as a main component, the polyether modified silicone and the antistatic agent. A method of adding a polyether-modified silicone and an antistatic agent to a release agent containing dimethylpolysiloxane as a main component, mixing and then adding and mixing a catalyst for curing the release agent, Peeling containing dimethylpolysiloxane as a main component Method of diluting an agent with an organic solvent in advance, adding and mixing a polyether-modified silicone and an antistatic agent and a catalyst for curing the release agent, diluting the release agent containing a siloxane as a main component with the organic solvent in advance, the catalyst May be added, mixed, and then added and mixed with polyether modified silicone and an antistatic agent. Moreover, you may add the material which assists the antistatic effect, such as a close_contact | adherence improvement agent, such as a silane coupling agent, and a compound containing a polyoxyalkylene group, as needed.

  The mixing ratio of the release agent containing dimethylpolysiloxane as the main component to the polyether-modified silicone and the antistatic agent is not particularly limited, but based on the solid content 100 of the release agent containing dimethylpolysiloxane as the main component, The ratio of about 5 to 100 is preferable in solid content of the polyether-modified silicone and the antistatic agent. When the addition amount in terms of solid content of the polyether-modified silicone and the antistatic agent is less than a ratio of 5 with respect to the solid content 100 of the release agent containing dimethylpolysiloxane as a main component, antistatic on the surface of the pressure-sensitive adhesive layer The amount of transfer of the agent also decreases, and the pressure-sensitive adhesive is less likely to exhibit the antistatic function. In addition, when the addition amount in terms of solid content of the polyether-modified silicone and the antistatic agent exceeds a ratio of 100 to the solid content of the release agent containing dimethylpolysiloxane as the main component, the polyether-modified silicone and the antistatic Since the release agent containing dimethylpolysiloxane as a main component together with the agent is also transferred to the surface of the pressure-sensitive adhesive layer, the pressure-sensitive adhesive properties of the pressure-sensitive adhesive may be deteriorated.

  The method for forming the pressure-sensitive adhesive layer 2 and the method for bonding the release film 5 to the base film 1 of the antistatic surface protective film 10 according to the present invention may be performed by a known method, and is not particularly limited. Specifically, (1) A method of bonding the release film 5 after applying the resin composition for forming the pressure-sensitive adhesive layer 2 on one side of the base film 1, drying it to form the pressure-sensitive adhesive layer, (2) The method of bonding the base film 1 may be mentioned after the resin composition for forming the pressure-sensitive adhesive layer 2 is applied to the surface of the release film 5 and dried to form the pressure-sensitive adhesive layer, Either method may be used.

  The pressure-sensitive adhesive layer 2 may be formed on the surface of the base film 1 by a known method. Specifically, known coating methods such as reverse coating, comma coating, gravure coating, slot die coating, Mayer bar coating, air knife coating and the like can be used.

  Similarly, the release agent layer 4 may be formed on the resin film 3 by a known method. Specifically, known coating methods such as gravure coating, mayer bar coating, air knife coating and the like can be used.

FIG. 2 is a cross-sectional view showing a state in which the release film is peeled off from the antistatic surface protective film of the present invention.
Of the silicone compound and antistatic agent (symbol 7) liquid at 20 ° C. contained in the release agent layer 4 of the release film 5 by removing the release film 5 from the antistatic surface protective film 10 shown in FIG. A part is transferred (adhered) to the surface of the pressure-sensitive adhesive layer 2 of the antistatic surface protective film 10. Therefore, in FIG. 2, the silicone compound and the antistatic agent which are liquid at 20 ° C. transferred to the surface of the pressure-sensitive adhesive layer 2 of the antistatic surface protective film are schematically shown by spots of reference numeral 7.
In the antistatic surface protective film according to the present invention, the antistatic surface protective film 11 in a state in which the release film shown in FIG. 2 is peeled off is transferred to the surface of the pressure-sensitive adhesive layer 2 when pasting the adherend. At 20 ° C., the silicone compound and the antistatic agent which are liquid come in contact with the surface of the adherend. As a result, when the antistatic surface protective film is peeled again from the adherend, it is possible to suppress the peeling charging voltage low.

FIG. 3 is a cross-sectional view showing an embodiment of the optical component of the present invention.
The release film 5 is peeled off from the antistatic surface protection film 10 of the present invention, and in a state where the pressure-sensitive adhesive layer 2 is exposed, it is bonded to the optical component 8 as an adherend via the pressure-sensitive adhesive layer 2 Ru.
That is, FIG. 3 shows an optical component 20 to which the antistatic surface protective film 10 of the present invention is bonded. Examples of optical components include optical films such as a polarizing plate, a retardation plate, a lens film, a polarizing plate also serving as a retardation plate, and a polarizing plate used as a lens film. Such an optical component is used as a component of a liquid crystal display device such as a liquid crystal display panel or an optical system device of various instruments. Moreover, as an optical component, films for optics, such as an antireflection film, a hard coat film, and a transparent conductive film for touch panels, are also mentioned. In particular, protection of optical films such as low reflection treated polarizing plates (LR polarizing plates) and antiglare low reflection treated polarizing plates (AG-LR polarizing plates) whose surfaces are treated with a silicone compound or fluorine compound to prevent contamination It can be suitably used as an antistatic surface protective film to be bonded to a surface that has been subjected to a stain treatment.
According to the optical component of the present invention, when the antistatic surface protective film 10 is peeled and removed from the optical component (film for optics) which is an adherend, the peeling voltage can be suppressed sufficiently low. There is no fear of destroying circuit parts such as IC, TFT elements, gate line drive circuits, etc., and the production efficiency in the process of manufacturing a liquid crystal display panel etc. can be enhanced, and the reliability of the production process can be maintained.

  The invention will now be further described by way of examples.

<Production of Pressure-Sensitive Adhesive Composition>
Example 1
Nitrogen gas was introduced into a reactor equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen inlet tube to replace air in the reactor with nitrogen gas. Thereafter, 100 parts by weight of 2-ethylhexyl acrylate and 5.0 parts by weight of 8-hydroxyoctyl acrylate were added to the reaction apparatus, and 60 parts by weight of a solvent (ethyl acetate) was added. Thereafter, 0.1 parts by weight of azobisisobutyronitrile as a polymerization initiator is dropped over 2 hours, and the mixture is reacted at 65 ° C. for 6 hours to obtain an acrylic copolymer solution of Example 1 having a weight average molecular weight of 500,000. Obtained. To this acrylic copolymer solution, 8.5 parts by weight of acetylacetone is added and stirred, then 2.0 parts by weight of Coronate HX (isocyanurate of hexamethylene diisocyanate compound) and 0.1 parts by weight of titanium trisacetylacetonate Parts were added and stirred and mixed to obtain a pressure-sensitive adhesive composition of Example 1.

[Examples 2 to 6 and Comparative Examples 1 to 3]
Pressure-sensitive adhesive compositions of Examples 2 to 6 and Comparative Examples 1 to 3 in the same manner as Example 1, except that the composition of the pressure-sensitive adhesive composition of Example 1 was changed as described in Table 1 and Table 2, respectively. I got a thing. In Tables 1 and 2, the monomers (copolymerized) contained in the acrylic copolymer are (A), (B), (C), (G), and a "carboxyl group-containing monomer".

  Table 1 and Table 2 divide the integral table which shows the compounding ratio of each component into two, and all enclose the numerical value of the weight part calculated | required as the sum total of (A) group as 100 weight part in a parenthesis Indicated. In addition, the compound names of the abbreviations of the respective components used in Tables 1 and 2 are shown in Tables 3 and 4. In addition, Coronate (registered trademark) HX, HL and L are trade names of Nippon Polyurethane Industry Co., Ltd., Takenate (registered trademark) D-140N, D-127N and D-110N are trade names of Mitsui Chemical Co., Ltd. It is.

<Synthesis of Bifunctional Isocyanate Compound>
The bifunctional isocyanate compound of Synthesis Examples 1 and 2 was synthesized by the following method. As shown in Tables 5 and 6, a diisocyanate and a diol compound are mixed in a molar ratio: NCO / OH = 16 ratio, reacted at 120 ° C. for 3 hours, and then under reduced pressure using a thin film evaporator. Unreacted diisocyanate was removed to obtain the desired bifunctional isocyanate compound.

<Preparation of antistatic surface protection film>
Example 1
Addition reaction type silicone (Toray Dow Corning, product name: SRX-345) 5 parts by weight, polyether-modified silicone (Toray Dow Corning product, product name: SH8400) 0.15 parts by weight, perchloric acid 5 parts by weight of lithium 10% ethyl acetate solution, 95 parts by weight of a 1: 1 mixed solvent of toluene and ethyl acetate, and 0.05 parts by weight of a platinum catalyst (manufactured by Toray Dow Corning Co., Ltd., product name: SRX-212 catalyst) Were mixed and stirred and mixed to prepare a paint for forming the release agent layer of Example 1. The paint for forming the release agent layer of Example 1 is coated on the surface of a polyethylene terephthalate film having a thickness of 38 μm with a Mayer to a dry thickness of 0.2 μm, and a hot air circulating oven at 120 ° C. The resultant was dried for 1 minute to obtain a release film of Example 1.
The pressure-sensitive adhesive composition of Example 1 is applied to the surface of a 38 μm thick polyethylene terephthalate film to a dry thickness of 20 μm, and then dried for 2 minutes in a hot air circulating oven at 100 ° C. The pressure-sensitive adhesive layer was formed. Then, the release agent layer (silicone-treated surface) of the release film of Example 1 produced above was bonded to the surface of the pressure-sensitive adhesive layer. The obtained pressure-sensitive adhesive film was kept at a temperature of 40 ° C. for 5 days to cure the pressure-sensitive adhesive, whereby an antistatic surface protective film of Example 1 was obtained.

[Examples 2 to 6]
An antistatic surface protective film of Examples 2 to 6 was obtained in the same manner as Example 1 except that the pressure-sensitive adhesive compositions of Example 1 were changed to the adhesive compositions of Examples 2 to 6, respectively.

Comparative Example 1
5 parts by weight of an addition reaction type silicone (made by Toray Dow Corning, product name: SRX-345), 95 parts by weight of a 1: 1 mixed solvent of toluene and ethyl acetate, and a platinum catalyst (made by Toray Dow Corning) Product name: SRX-212 catalyst) 0.05 parts by weight were mixed, stirred and mixed to prepare a paint for forming the release agent layer of Comparative Example 1. The paint for forming the release agent layer of Comparative Example 1 is coated on the surface of a polyethylene terephthalate film having a thickness of 38 μm with a Mayer to a dry thickness of 0.2 μm, and a hot air circulating oven at 120 ° C. The resultant was dried for 1 minute to obtain a release film of Comparative Example 1.
The pressure-sensitive adhesive composition of Comparative Example 1 is applied to the surface of a 38 μm thick polyethylene terephthalate film so that the thickness after drying is 20 μm, and then dried in a hot air circulating oven at 100 ° C. for 2 minutes. The pressure-sensitive adhesive layer was formed. Thereafter, the release agent layer (silicone-treated surface) of the release film of Comparative Example 1 prepared above was bonded to the surface of the pressure-sensitive adhesive layer. The obtained pressure-sensitive adhesive film was kept at 40 ° C. for 5 days to cure the pressure-sensitive adhesive, whereby an antistatic surface protective film of Comparative Example 1 was obtained.

Comparative Example 2
An antistatic surface protective film of Comparative Example 2 was obtained in the same manner as in Comparative Example 1 except that the pressure-sensitive adhesive composition of Comparative Example 1 was changed to the pressure-sensitive adhesive composition of Comparative Example 2.

Comparative Example 3
An antistatic surface protective film of Comparative Example 3 was obtained in the same manner as in Example 1 except that the pressure-sensitive adhesive composition of Example 1 was changed to the adhesive composition of Comparative Example 3.

  Table 7 shows the composition and thickness of the release agent layer in the antistatic surface protective films of Examples 1 to 6 and Comparative Examples 1 to 3.

<Test method and evaluation>
The surface protective films in Examples 1 to 6 and Comparative Examples 1 to 3 are aged for 7 days in an atmosphere of 23 ° C. and 50% RH, and then the release film (PET film coated with silicone resin) is peeled off to cause adhesion What exposed the agent layer was made into the measurement sample of surface resistivity.
Furthermore, the surface protection film in which the pressure-sensitive adhesive layer is exposed is attached to the surface of the polarizing plate attached to the liquid crystal cell through the pressure-sensitive adhesive layer, and left for 1 day. A sample subjected to an autoclave treatment and left at room temperature for a further 12 hours was used as a measurement sample of the adhesive strength, the peel voltage and reworkability.

<Adhesiveness>
Low-speed peeling speed (0.3 m / min) and high speed using a tensile tester in the direction of 180 ° with the measurement sample obtained above (the 25 mm wide surface protective film attached to the surface of the polarizing plate) It peeled off at the peeling speed of (30 m / min), and made the measured peeling strength adhesive.

<Surface resistivity>
After aging, before bonding to a polarizing plate, the release film (PET film coated with silicone resin) is peeled off to expose an adhesive layer, and using a resistivity meter HIRESTA UP-HT450 (manufactured by Mitsubishi Chemical Analytech Co., Ltd.) The surface resistivity of the pressure-sensitive adhesive layer was measured.

<Peeling voltage>
The voltage (charging voltage) generated when the polarizing plate is charged when the measurement sample obtained above is peeled at 180 ° at a tensile speed of 30 m / min is defined as the high accuracy electrostatic sensor SK-035, SK-200 (stock It measured using the company Keyence make, and made the maximum value of the measured value the peeling zone voltage.

<Reworkability>
After tracing the surface protection film of the measurement sample obtained above with a ballpoint pen (load 500 g, 3 reciprocations), the surface protection film is peeled off from the polarizing plate and the surface of the polarizing plate is observed to contaminate the polarizing plate I confirmed that there was no transition. The evaluation target criteria are: "○" when there is no contamination transfer on the polarizing plate, "△" when contamination transfer is confirmed at least partially along the locus traced with a ballpoint pen, along the locus traced with a ballpoint pen The case where the contamination transfer was confirmed and the detachment of the adhesive was also confirmed from the adhesive surface was evaluated as "x".

Table 8 shows the evaluation results. The surface resistivity is represented by a method in which “m × 10 ^{+ n} ” is “mE + n” (where, m is an arbitrary real number and n is a positive integer).

From the measurement results shown in Table 8, the following can be understood.
The antistatic surface protective films of Examples 1 to 6 according to the present invention have adequate adhesion, no contamination to the surface of the adherend, and when the antistatic surface protective film is peeled from the adherend Peeling voltage is low.
On the other hand, the antistatic surface protective film of Comparative Example 1 in which the silicone compound and the antistatic agent are added to the pressure-sensitive adhesive layer has a low surface resistivity of the pressure-sensitive adhesive layer and is good. It was expensive and inferior to reworkability. Moreover, in Comparative Example 2, the pressure sensitive adhesive gelled and could not be applied, probably because the amount of the crosslinking accelerator added was large. Moreover, in the comparative example 3, since the monomer containing a carboxyl group was included, adhesive force was large and rework property was somewhat inferior.
That is, in Comparative Examples 1 and 2 in which a silicone compound and an antistatic agent are mixed in a pressure-sensitive adhesive, it is difficult to simultaneously achieve reduction in the release voltage and contamination with respect to the adherend. On the other hand, after adding the silicone compound and the antistatic agent to the release agent layer, in Examples 1 to 6 in which the silicone compound and the antistatic agent are transferred to the surface of the adhesive layer, the release voltage is small with a small amount. As a result, there was no contamination on the adherend, and a good antistatic surface protective film was obtained.

The antistatic surface protective film of the present invention is, for example, a surface of the optical component etc. in the production process of optical films such as a polarizing plate, a retardation plate, a lens film for display, etc., other various optical components etc. Can be used to protect In particular, when used as an antistatic surface protective film for an optical film such as an LR polarizing plate or an AG-LR polarizing plate, the surface of which has been treated to prevent contamination with a silicone compound or a fluorine compound, peeling from the adherend At the same time, the amount of static electricity generated can be reduced.
The antistatic surface protective film of the present invention can improve the yield of the production process because it has excellent anti-peeling antistatic performance with little contamination to the adherend and further without deterioration with time, which is an industrial application value Is large.

DESCRIPTION OF SYMBOLS 1 ... base film, 2 ... adhesive layer, 3 ... resin film, 4 ... release agent layer, 5 ... release film, 7 ... silicone compound and antistatic agent liquid at 20 ° C, 8 ... adherend (optical Parts), 10: Antistatic surface protective film, 11: Antistatic surface protective film from which the peeling film is peeled, 20: Optical component pasted with the antistatic surface protective film.

Claims (1)

A method for producing an antistatic surface protective film, wherein an adhesive layer is formed on one side of a base film made of a resin having transparency, and an antistatic agent is transferred to the surface of the adhesive layer, ,
The pressure-sensitive adhesive layer cross-links a pressure-sensitive adhesive composition containing an acrylic polymer, (D) a bifunctional or higher isocyanate compound, (E) a crosslinking accelerator, and (F) a ketoenol tautomeric compound. The pressure-sensitive adhesive layer
The said acryl-type polymer is a copolymerization in which the carbon number of the (A) alkyl group contains (B) a hydroxyl group as a monomer group which can be copolymerized with at least 1 sort (s) of C4 to C18 (meth) acrylic acid ester monomer And / or (C) at least one selected from the group of copolymerizable monomers consisting of (C) a hydroxyl group-free nitrogen-containing vinyl monomer or an alkoxy group-containing alkyl (meth) acrylate monomer Acrylic polymer, which is
The weight ratio of (E) :( F) is 1:80 to 1: 500 as a ratio of the (F) ketoenol tautomer compound to the (E) crosslinking accelerator,
A release agent layer containing an antistatic agent is laminated on one side of the resin film, and the release agent layer comprises a release agent mainly composed of dimethylpolysiloxane, a silicone compound which is liquid at 20 ° C., and After laminating a release film formed of a resin composition containing an inhibitor with the surface of the pressure-sensitive adhesive layer through the release agent layer, the release film is peeled off from the surface of the pressure-sensitive adhesive layer, A method of producing an antistatic surface protection film, comprising transferring the silicone compound of the release agent layer and the antistatic agent only to the surface of the pressure-sensitive adhesive layer.

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