JP5532283B2 - Adhesive, adhesive film, and surface protective film for optical member - Google Patents

Description

  The present invention mainly relates to an adhesive that can be used for a surface protective film of an optical member.

  A liquid crystal display provided in a liquid crystal display device such as a liquid crystal television is composed of various optical members including a polarizing plate. A surface protective film is usually attached to these optical members in order to prevent dust and the like from adhering to the surface and to prevent scratches during transportation.

  As the surface protective film, a film having an adhesive layer on the surface of a transparent plastic film such as polyethylene terephthalate is generally used. The surface protective film is usually affixed to the optical member in the manufacturing process of the liquid crystal display etc. in addition to the transportation of the optical member such as a polarizing plate, but until the liquid crystal display etc. is shipped as a final product, It is peeled off from the surface of the optical member and disposed of.

  However, since the optical member is generally made of a material that is easily charged, static electricity tends to be generated when the surface protective film is peeled off. As a result, there is a problem that dirt such as dust tends to adhere to the surface of the optical member. It was.

  Therefore, the protective film is required to have a very high level of antistatic property that does not charge the surface of the optical member during peeling.

  As a method of imparting excellent antistatic properties to the surface protective film, a method of using a material having antistatic properties as an adhesive constituting the film has been studied.

  As such an adhesive, for example, an adhesive composition containing an ionic liquid and a (meth) acrylic polymer having 0.1 to 100% by mass of (meth) acrylic acid alkylene oxide is excellent in antistatic properties, It is known that it can be used for manufacture of a surface protection film (for example, refer patent document 1).

  However, the pressure-sensitive adhesive composition containing the (meth) acrylic polymer having a high content of the (meth) acrylic acid alkylene oxide has a very high viscosity and poor fluidity, so that the coating workability is poor. In some cases, it is difficult to uniformly coat the substrate surface.

  On the other hand, a pressure-sensitive adhesive composition containing a (meth) acrylic polymer having a relatively small content of the (meth) acrylic acid alkylene oxide has a relatively good coating workability, but is required by the industry. In some cases, it was difficult to develop a very high level of antistatic properties.

JP 2006-63311 A

  The problem to be solved by the present invention is a pressure-sensitive adhesive having very excellent antistatic properties and excellent coating workability, a pressure-sensitive adhesive film having a pressure-sensitive adhesive layer comprising the pressure-sensitive adhesive, and surface protection for optical members Is to provide a film.

  The present inventors have studied to achieve both excellent antistatic properties and coating workability, but in order to form an adhesive layer having a very high level of antistatic properties required by the industry. Still thought that it was necessary to contain a certain amount or more of a polyalkylene oxide chain derived from (meth) acrylic acid alkylene oxide or the like.

  The inventors of the present invention have found that the increase in the amount of (meth) acrylic acid alkylene oxide increases the viscosity of the pressure-sensitive adhesive and causes the fluidity to decrease. Cause entanglement between the polymers due to mechanical and physical interactions, and increase in the amount of alkylene oxide chains, which increases the hydrophilicity of the polymer and decreases the solubility of the polymer in the solvent. I thought that.

Therefore, the alkylene oxide chain that contributes to antistatic properties is not supplied by the acrylic polymer, but is used as an isocyanate-based cross-linking agent that is mixed with the acrylic polymer immediately before the pressure-sensitive adhesive is used. The use of an isocyanate-based crosslinking agent having a chain was studied.
As a result, after mixing the acrylic polymer and the cross-linking agent, if it is within a practically sufficient time, the antistatic property is excellent without causing a decrease in fluidity due to a significant increase in viscosity of the adhesive. It came to find the adhesive which has the property and coating workability.

That is, the present invention includes a hydroxyl group-containing acrylic polymer (A), a cross-linking agent (B) having a polyalkylene oxide chain and an isocyanate group, and cation components such as an imidazolium cation, a pyridium cation, a piperidinium cation, and an ammonium cation. , A sulfonium cation or a phosphonium cation, an ionic liquid composed of Br ⁻ , NCO ₃ ⁻ , CH ₃ COO ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , perfluoroalkanesulfonate or perfluoroalkanesulfonylimide as an anion component , or And an adhesive comprising an alkali metal salt (C) having a compound containing a fluorine atom as an anionic component .

  Moreover, this invention relates to the adhesive film and the surface protection film for optical members in which the adhesion layer which consists of the said adhesive was formed in the single side | surface or both surfaces of the plastic base material.

  The present invention also provides a mixture in which the hydroxyl group-containing acrylic polymer (A) and the ionic compound (C) are dissolved or dispersed in a solvent, the polyalkylene oxide chain and a crosslinking agent (B) having an isocyanate group. The present invention relates to a method for producing a pressure-sensitive adhesive film or a surface protective film for an optical member, characterized in that the pressure-sensitive adhesive is immediately applied to a plastic substrate after curing to prepare a pressure-sensitive adhesive.

  The pressure-sensitive adhesive of the present invention is suitable for use as a surface protective film for various optical members such as polarizing plates because it is excellent in coating workability and can impart excellent antistatic properties to a substrate. Can do.

  The pressure-sensitive adhesive of the present invention comprises a hydroxyl group-containing acrylic polymer (A), a cross-linking agent (B) having a polyalkylene oxide chain and an isocyanate group, an ionic compound (C), and other additives as necessary. It is the adhesive which contains.

  The pressure-sensitive adhesive is preferably a solution in which a hydroxyl group-containing acrylic polymer (A), the cross-linking agent (B), or an ionic compound (C) is dissolved or dispersed in an organic solvent, but is dissolved or dispersed in an aqueous medium. Moreover, when using a liquid thing as an ionic compound (C) so that it may mention later, those solvents do not need to be included.

  The pressure-sensitive adhesive of the present invention provides a polyalkylene oxide chain that is considered to contribute greatly to imparting antistatic properties by the crosslinking agent (B). Therefore, an acrylic polymer having a large amount of introduced polyalkylene oxide chain is used. Compared to the pressure sensitive adhesive, it does not cause a significant increase in viscosity.

  In addition, the pressure-sensitive adhesive layer formed of the pressure-sensitive adhesive of the present invention is one in which crosslinking between the hydroxyl group-containing acrylic polymer (A) and the crosslinking agent (B) has progressed to some extent. There is a polyalkylene oxide chain in the same amount as. Therefore, the pressure-sensitive adhesive of the present invention can form a pressure-sensitive adhesive layer having a very high level of antistatic property comparable to the conventional level without deteriorating the coating workability.

  The gel fraction of the pressure-sensitive adhesive layer formed using the pressure-sensitive adhesive of the present invention is preferably 85% by mass or more by appropriately adjusting the amount of the crosslinking agent (B) used, etc. It is particularly preferable that the content is at least mass%. The pressure-sensitive adhesive layer having a gel fraction in such a range has good adhesive force and removability.

First, the hydroxyl group-containing acrylic polymer (A) used in the present invention will be described.
The hydroxyl group-containing acrylic polymer (A) constituting the pressure-sensitive adhesive can be a main component constituting the pressure-sensitive adhesive, and the same ones as conventionally used pressure-sensitive adhesives can be used.

  As the hydroxyl group-containing acrylic polymer (A), those having no polyalkylene oxide chain may be used, but the amount of polyalkylene oxide chain present in the adhesive layer is increased, and antistatic properties are increased. From the viewpoint of further improvement, it is preferable to use an acrylic polymer having a polyalkylene oxide chain.

  Although the said polyalkylene oxide chain changes also with the addition amount of alkylene oxide, it is preferable that it exists normally 1-30 mass% with respect to the whole said hydroxyl-containing acrylic polymer (A), and is 5-25 mass%. It is more preferable that it is more preferably 8 to 18% by mass in order to maintain excellent coating workability.

  The polyalkylene oxide chain may be a chain structure composed of, for example, a polyethylene oxide chain, a polypropylene oxide chain, a polybutylene oxide chain, and a copolymer thereof, but the polyethylene oxide chain is effective for antistatic performance. It is more preferable because it can be imparted.

  In addition, the polyalkylene oxide chain is preferably one having 1 to 100 moles of alkylene oxide added, more preferably 5 to 30 moles added, and 5 to 20 moles added. Particularly preferred. By using a hydroxyl group-containing acrylic polymer having a polyalkylene oxide chain in such a range, a pressure-sensitive adhesive capable of forming a pressure-sensitive adhesive layer having excellent antistatic properties can be obtained.

Moreover, the said hydroxyl-containing acrylic polymer (A) has a hydroxyl group as a functional group which reacts with the isocyanate group which the crosslinking agent (B) mentioned later has.
The hydroxyl group is preferably present in an amount of 0.05 to 2.5% by mass relative to the total amount of the acrylic polymer (A). It is preferable because it can crosslink well with B) and impart good removability.

  Moreover, it is preferable that the acid value of the said hydroxyl-containing acrylic polymer (A) is the range of 0.1-8, and it is more preferable that it is the range of 0.5-3. By using an acrylic polymer having an acid value in the above range, the crosslinking reaction can be moderately accelerated without significantly reducing the pot life after mixing with the crosslinking agent (B). The said acid value can be adjusted by using the carboxyl group-containing unsaturated monomer mentioned later as a monomer which comprises a hydroxyl-containing acrylic polymer (A).

  Moreover, since the said hydroxyl-containing acrylic polymer (A) can provide favorable adhesive force and removability, it is preferable to have a weight average molecular weight of the range of 200,000-2 million.

  The hydroxyl group-containing acrylic polymer (A) preferably has a glass transition temperature of −25 ° C. or lower because it can provide good adhesive force.

  The said hydroxyl-containing acrylic polymer (A) can be manufactured by radical polymerization resulting from the polymerizable unsaturated double bond which various acrylic monomers have.

  Examples of the acrylic monomer include polyalkylene oxide group-containing acrylic monomers, hydroxyl group-containing acrylic monomers, carboxyl group-containing acrylic monomers, alkyl group-containing acrylic monomers, and other conventionally known acrylic monomers. Various acrylic monomers can be used alone or in combination.

  The polyalkylene oxide group-containing acrylic monomer is an acrylic monomer having a polyalkylene oxide chain as described above, for example, polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, polyethylene glycol-polypropylene glycol. (Meth) acrylate, polyethylene glycol-polybutylene glycol (meth) acrylate, polypropylene glycol-polybutylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, ethoxypolyethylene glycol (meth) acrylate, butoxypolyethylene glycol (meth) acrylate , Octoxy polyethylene glycol (meth) acrylate, Lauroxy polyethylene glycol It can be used polypropylene glycol (meth) acrylate - Le (meth) acrylate, stearoxy polyethylene glycol (meth) acrylate, phenoxy polyethylene glycol (meth) acrylate, methoxy polypropylene glycol (meth) acrylate, octoxypolyethylene glycol.

  The polyalkylene oxide chain possessed by the acrylic monomer is a polymethylene oxide chain, a polyethylene oxide chain, a polypropylene oxide chain, a polybutylene oxide chain, etc., and is generally composed of an alkylene group having 1 to 6 carbon atoms. It is preferable to use it. The polyalkylene oxide chain may be linear or branched. In addition, the polyalkylene oxide chain is preferably an alkylene oxide added in an amount of 1 to 100 mol, more preferably 5 to 30 mol added, and particularly preferably 5 to 20 mol added in the same manner as described above. .

  It is preferable to use 1-35 mass% of said polyalkylene oxide chain containing acrylic monomers with respect to the whole quantity of the acrylic monomer used for manufacture of a hydroxyl-containing acrylic polymer (A). It is more preferable to use it, and it is especially preferable that it is 10-20 mass%. By using the polyalkylene oxide chain-containing acrylic monomer within the above range, an adhesive having excellent antistatic properties and good coating workability can be obtained.

  Moreover, as a hydroxyl-containing acrylic monomer which can be used for manufacture of the said hydroxyl-containing acrylic polymer (A), 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl ( (Meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxyhexyl (meth) acrylate, 6-hydroxyhexyl (meth) acryl, 8-hydroxyoctyl (meth) acrylate, 10 -Hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, etc. can be used, among which 2-hydroxyethyl acrylate, 3-hydroxypropyl (meth) acrylate, and 4-hydroxybutyl acrylate It is good adhesion, and preferred because it can impart removability to use rate.

  The hydroxyl group-containing acrylic monomer is preferably used in an amount of 0.5 to 15% by mass, based on the total amount of the acrylic monomer used for the production of the hydroxyl group-containing acrylic polymer (A). % Use is particularly preferred. By using the hydroxyl group-containing acrylic monomer within the above range, the cross-linking of the pressure-sensitive adhesive layer suitably proceeds, and when the pressure-sensitive adhesive film or surface protective film of the present invention is peeled from the surface of the substrate such as an optical member, the group It is possible to prevent a part of the pressure-sensitive adhesive from remaining on the material surface.

  Examples of the carboxyl group-containing acrylic monomer that can be used in the production of the hydroxyl group-containing acrylic polymer (A) include acrylic acid, methacrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, (anhydrous ) Itaconic acid, (anhydrous) maleic acid, fumaric acid, crotonic acid and the like can be used, and among them, acrylic acid and methacrylic acid are preferably used.

  The carboxyl group-containing acrylic monomer is preferably used in an amount of 0.01 to 1% by mass based on the total amount of the acrylic monomer used for the production of the hydroxyl group-containing acrylic polymer (A), and more preferably 0.05. It is particularly preferable to use ~ 0.5% by mass.

  Examples of the alkyl group-containing acrylic monomer that can be used for the production of the hydroxyl group-containing acrylic polymer (A) include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, s- Butyl (meth) acrylate, t-butyl (meth) acrylate, isobutyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, n- Nonyl (meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, n-undecyl (meth) acrylate, n-dodecyl (meth) acrylate, n-tridecyl (meth) acrylate, n-teto Can be used decyl (meth) acrylate, among others n- butyl acrylate, the use of 2-ethylhexyl acrylate is preferable because it can impart good adhesion.

  It is preferable to use 49-99.5 mass% of said alkyl group containing acrylic monomers with respect to the whole quantity of the acrylic monomer used for manufacture of a hydroxyl-containing acrylic polymer (A). When in this range, good adhesive strength can be imparted.

  Examples of the other acrylic monomer that can be used for the production of the hydroxyl group-containing acrylic polymer (A) include an amide group-containing acrylic monomer, an amino group-containing acrylic monomer, and an imide group-containing acrylic monomer. These nitrogen atom-containing acrylic monomers can be used.

  Examples of the amide group-containing acrylic monomer include acrylamide, methacrylamide, diethylacrylamide, N-vinylpyrrolidone, N, N-dimethylacrylamide, N, N-dimethylmethacrylamide, N, N-diethylacrylamide, and N, N. -Diethylmethacrylamide, N, N'-methylenebisacrylamide, N, N-dimethylaminopropyl acrylamide, N, N-dimethylaminopropyl methacrylamide, diacetone acrylamide and the like can be used.

  As the amino group-containing acrylic monomer, for example, aminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate and the like can be used.

  As the imide group-containing acrylic monomer, for example, cyclohexylmaleimide, isopropylmaleimide, N-cyclohexylmaleimide, itaconimide and the like can be used.

  In addition to the above, other acrylic monomers include, for example, styrene sulfonic acid, allyl sulfonic acid, 2- (meth) acrylamide-2-methylpropane sulfonic acid, (meth) acrylamide propane sulfonic acid, sulfopropyl. Sulfonic acid group-containing acrylic monomers such as (meth) acrylate, (meth) acryloyloxynaphthalene sulfonic acid, sodium vinyl sulfonate, 2-hydroxyethylacryloyl phosphate group-containing acrylic monomer, acrylonitrile, methacrylic acid Cyano group-containing monomers such as rhonitrile, glycidyl group-containing acrylic monomers such as glycidyl (meth) acrylate, methyl glycidyl (meth) acrylate, and allyl glycidyl ether, vinyl acetate, vinyl propionate, lauric acid Cycloalkenyl, styrene, chlorostyrene, chloromethylstyrene, alpha-methyl styrene, other substituted styrenes, methyl vinyl ether, ethyl vinyl ether, may be used in combination, such as isobutyl vinyl ether.

  Examples of the method for producing the hydroxyl group-containing acrylic polymer (A) using the various acrylic monomers described above include a radical polymerization method resulting from the polymerizable double bond of the acrylic monomer. Specifically, the above-mentioned various acrylic monomers, a polymerization initiator, and an organic solvent such as ethyl acetate are preferably mixed and stirred at a temperature of 40 to 90 ° C. to advance radical polymerization. It is done.

  Examples of the polymerization initiator include peroxides such as hydrogen peroxide, potassium persulfate, sodium persulfate, and ammonium persulfate, and 2,2′-azobis- (2-aminodipropane) dihydrochloride, 2,2 '-Azobis- (N, N'-dimethyleneisobutylamidine) dihydrochloride, 2,2'-azobis {2-methyl-N- [1,1-bis (hydroxymethyl) -2-hydroxyethyl] propionamide } And the like can be used. It is preferable that the usage-amount of the said polymerization initiator is 0.01-5 mass parts with respect to 100 mass parts of whole quantity of the said acrylic monomer.

Next, the crosslinking agent (B) used in the present invention will be described.
The cross-linking agent (B) is a compound having a polyalkylene oxide chain and an isocyanate group, and forms a three-dimensional cross-linking structure with the acrylic polymer (A), giving the obtained adhesive layer excellent antistatic properties. This is a necessary compound.

  The ratio of the polyalkylene oxide chain with respect to the whole crosslinking agent (B) is preferably in the range of 5 to 50% by mass because an adhesive layer having good antistatic properties can be formed, and more preferably 10 to 40% by mass. It is more preferable that it is 12-30 mass%.

  Moreover, since the ratio of the isocyanate group with respect to the whole said crosslinking agent (B) carries out a crosslinking reaction efficiently with the said acrylic polymer (A), 0.05-6 mol is preferable per 1000g of crosslinking agents (B), and 0 .1 to 5 mol is more preferable, and 0.2 to 4 mol is more preferable.

  As the crosslinking agent (B), specifically, a crosslinking agent (B1) having a structure in which a polyalkylene oxide is added to the isocyanate group-containing compound (b1) can be used.

  Moreover, as said crosslinking agent (B), the crosslinking agent (B2) which consists of a vinyl polymer which has an isocyanate group and a polyalkylene oxide chain | strand, for example can also be used.

  Even when an aqueous medium is used as the solvent for the pressure-sensitive adhesive of the present invention, both the crosslinking agents (B1) and (B2) can be used. In such a case, for example, the core layer has been conventionally known. It is also possible to use a core-shell type crosslinking agent (B3) comprising an isocyanate group-containing crosslinking agent and having a shell layer made of a vinyl polymer having an isocyanate group and a polyalkylene oxide chain.

  The amount of the crosslinking agent (B) used is the ratio between the number of moles of isocyanate groups (NCO) of the crosslinking agent (B) and the number of moles of hydroxyl groups (OH) of the hydroxyl group-containing acrylic polymer (A) [ NCO / OH] is preferably in the range of 0.2 to 1.5, and more preferably 0.25 to 1. By using the crosslinking agent obtained by reacting at the above ratio, an adhesive having excellent wettability (accommodating property) and removability to the substrate can be obtained.

First, the crosslinking agent (B1) will be described.
As the crosslinking agent (B1), a compound having a structure in which polyalkylene oxide is added to a part of the isocyanate group of the isocyanate group-containing compound (b1) can be used.

  The crosslinking agent (B1) preferably has two or more isocyanate groups from the viewpoint of improving the crosslinking density of the adhesive layer. Moreover, since the ratio of the polyalkylene oxide chain with respect to the whole crosslinking agent (B1) is in the range of 5 to 50% by mass, an adhesive layer having good antistatic properties can be formed. It is more preferable that it is mass%, and it is especially preferable that it is 12-30 mass%.

  Moreover, as a weight average molecular weight of the said whole crosslinking agent (B1), it is preferable that it is the range of 200-5000, and the range of 250-2000 is more preferable. The crosslinking agent (B1) having a weight average molecular weight within such a range is preferable because it facilitates the crosslinking reaction with the hydroxyl group-containing acrylic polymer (A).

  As said isocyanate group containing compound (b1) which can be used for manufacture of the said crosslinking agent (B1), it is preferable to use the comparatively low molecular weight compound which has a 3 or more isocyanate group, for example. Specifically, isophorone diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, xylylene diisocyanate, 1,3-bisisocyanatomethylcyclohexane, hexamethylene diisocyanate, tetramethylxylylene diisocyanate, m- Dimers such as isopropenyl-α, α-dimethylbenzyl isocyanate, methylene bis-4-phenyl isocyanate, and p-phenylene diisocyanate, and trimers such as isocyanurate ring-containing polyisocyanate compounds, and further these are biuret and What reacted with polyhydric alcohols, such as a trimethylol propane, and a polyhydric amine can be used. Among them, as the isocyanate group-containing compound (b1), it is preferable to use an aliphatic or alicyclic isocyanate in order to avoid yellowing of the adhesive layer.

  Moreover, as a polyalkylene oxide added to the said isocyanate group containing compound (b1), polyethylene glycol, polypropylene glycol, etc. can be used, for example. Among them, it is preferable to use polyethylene glycol because it can provide good antistatic performance.

  As the polyalkylene oxide, those formed by addition polymerization of alkylene oxide can be used. The amount of alkylene oxide added varies depending on the amount of alkylene oxide chain present in the pressure-sensitive adhesive layer, but it is preferably about 1 to 30 mol in order to form a pressure-sensitive adhesive layer excellent in antistatic properties, More preferably, it is 25 moles.

  Further, the weight average molecular weight of the polyalkylene oxide is preferably one having a weight average molecular weight of 130 to 4500 and 200 to 2500 in order to form an adhesive layer having excellent antistatic properties. It is more preferable that it has 300-1500.

  It is preferable that the terminal of the polyalkylene oxide chain which the said crosslinking agent (B1) has is blocked from a viewpoint of suppressing reaction between crosslinking agents (B1). For example, the hydroxyl group present at one end of the polyoxyalkylene oxide chain is preferably blocked by an alkoxy group, a substituted alkoxy group, or the like, for example, blocked by a lower alkoxy group such as a methoxy group, an ethoxy group, or a butoxy group. More preferably.

  The crosslinking agent (B1) can be produced, for example, by mixing and reacting the isocyanate group-containing compound (b1) and the polyalkylene oxide in an atmosphere such as an inert gas.

Next, a crosslinking agent (B2) is demonstrated.
The crosslinking agent (B2) is made of a vinyl polymer having an isocyanate group and a polyalkylene oxide chain. For example, the same isocyanate group-containing compound (b2) as the aforementioned isocyanate group-containing compound (b1), a polyalkylene oxide chain, and A compound obtained by reacting with a vinyl polymer (b3) having an active hydrogen-containing group can be used.

  The crosslinking agent (B2) preferably has two or more isocyanate groups from the viewpoint of improving the crosslinking density of the adhesive layer. Moreover, since the ratio of the polyalkylene oxide chain with respect to the whole said crosslinking agent (B2) is the range of 5-50 mass%, since it can form the adhesion layer which has favorable antistatic property, Furthermore, it is 10-40. It is more preferable that it is mass%, and it is especially preferable that it is 12-30 mass%.

  Moreover, as a weight average molecular weight of the said whole crosslinking agent (B2), it is preferable that it is the range of 5000-200000, and the range of 8000-70000 is more preferable. The crosslinking agent (B2) having a weight average molecular weight in such a range is preferable because it facilitates the crosslinking reaction with the hydroxyl group-containing acrylic polymer (A).

  Examples of the vinyl polymer (b3) having a polyalkylene oxide chain and an active hydrogen-containing group that can be used for the production of the crosslinking agent (B2) include an acrylic polymer, a fluoroolefin polymer, a vinyl ester polymer, Among aromatic vinyl polymers and polyolefin polymers, those having a polyalkylene oxide chain and an active hydrogen-containing group can be used. Especially, it is preferable to use an acrylic polymer from a viewpoint of improving the compatibility of a hydroxyl-containing acrylic polymer (A) and a crosslinking agent (B2).

  The vinyl polymer (b3) preferably has a weight average molecular weight of 3000 to 100,000, more preferably 5,000 to 40,000. By using a vinyl polymer having a weight average molecular weight in such a range, an adhesive having good antistatic properties and coating workability can be obtained.

  The active hydrogen-containing group of the vinyl polymer (b3) mainly reacts with the isocyanate group of the isocyanate group-containing compound (b2). Examples of the active hydrogen-containing group include hydroxyl group, carboxyl group, phosphoric acid group, phosphorous acid group, sulfonic acid group, sulfinic acid group, mercapto group, silanol group, active methylene group, carbamate group, ureido group, carboxylic acid amide group, sulfone. Examples include acid amide groups, and among them, a hydroxyl group, an amino group, a carboxyl group, and an active methylene group are preferable, and a hydroxyl group and a carboxyl group are particularly preferable in terms of ease of introduction.

  The active hydrogen-containing group of the vinyl polymer (b3) is preferably present in the range of 0.01 to 5 mol, and in the range of 0.05 to 3 mol, per 1000 g of the vinyl polymer (b3). It is more preferable that the amount is 0.1 to 2 mol.

  The polyalkylene oxide chain preferably has a weight average molecular weight of 130 to 10,000, and more preferably 200 to 2500. Furthermore, it is particularly preferable that the resin has a weight average molecular weight of 300 to 1500 because an adhesive layer having excellent antistatic properties can be formed.

  As the polyalkylene oxide, those formed by addition polymerization of alkylene oxide can be used. The amount of alkylene oxide added varies depending on the amount of alkylene oxide chain present in the pressure-sensitive adhesive layer, but it is preferably about 1 to 30 mol in order to form a pressure-sensitive adhesive layer excellent in antistatic properties, More preferably, it is 25 moles.

  The amount of the polyalkylene oxide chain based on the whole vinyl polymer (b3) is preferably in the range of 10 to 90% by mass in order to form an adhesive layer having excellent antistatic properties, and is preferably 15 to 70% by mass. It is more preferable that it is in the range of 20 to 60% by mass.

  The vinyl polymer (b3) is produced, for example, by polymerizing a vinyl monomer having an active hydrogen-containing group, a vinyl monomer having a polyalkylene oxide chain, and other vinyl monomers as necessary. can do.

  Examples of the vinyl monomer having an active hydrogen-containing group include hydroxyl group-containing vinyl monomers such as 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate, (meth) acrylic acid, 2- Carboxy group-containing vinyl monomers such as carboxyethyl acrylate and crotonic acid, 2- (N-methylamino) ethyl (meth) acrylate, 2- (N-ethylamino) ethyl (meth) acrylate, 2- (N- amino group-containing vinyl monomers such as n-butylamino) ethyl (meth) acrylate and active methylene groups such as vinylacetoacetate, 2-acetoacetoxyethyl (meth) acrylate and 2-acetoacetoxypropyl (meth) acrylate The monomer which has can be used.

  Further, as the vinyl monomer having a polyalkylene oxide chain, for example, (meth) acrylic acid ester, crotonic acid ester, itaconic acid ester, fumaric acid ester, vinyl ether or the like having a polyoxyalkylene chain may be used. it can.

  Typical examples of the (meth) acrylic acid ester having a polyoxyalkylene chain include monomethoxy polyethylene glycol, monomethoxy polypropylene glycol, or mono-ether polyether diol having both oxyethylene units and oxypropylene units. Various monoalkoxylated polyether diols such as methoxy compounds and esters of (meth) acrylic acid can be used.

  The reaction between the isocyanate group-containing compound (b2) and the polyalkylene oxide chain and the vinyl polymer (b3) having an active hydrogen atom-containing group is, for example, mixed in an inert gas atmosphere. The method of reacting (i), the method of reacting by adding the vinyl polymer (b3) solution to the isocyanate group-containing compound (b2) (ii), the method of reacting the isocyanate group-containing compound (b2) with the vinyl polymer (b3) solution Addition and reaction can be performed by the method (iii) or the like, and among these, the method (i) or (ii) is preferable.

  The reaction is preferably allowed to proceed by heating and stirring at a temperature of about 50 to 130 ° C. for about 0.5 to 20 hours. Moreover, in the case of the said reaction, various well-known and usual catalysts which can accelerate | stimulate reaction with the isocyanate group of an isocyanate group containing compound (b2) and the active hydrogen containing group of the said vinyl polymer (b3) are used. Also good.

  Moreover, reaction of the said isocyanate group containing compound (b2) and the said vinyl polymer (b3) is the said isocyanate group containing compound (b2) with respect to the molar amount of the active hydrogen containing group which the said vinyl polymer (b3) has. ) Is preferably carried out under conditions where the molar ratio of the isocyanate groups is excessive. When reacted under such conditions, the crosslinking agent (B) is a mixture of the crosslinking agent (B2) and the isocyanate group-containing compound (b2).

  The molar ratio is preferably in the range of 3 to 350, more preferably in the range of 5 to 300, and particularly preferably in the range of 10 to 250 because good removability can be imparted to the pressure-sensitive adhesive of the present invention. A range of 15-100 is most preferred. In addition, when manufacturing a vinyl polymer (b3) by methods other than the above, you may mix a vinyl polymer (b3) and an isocyanate group containing compound (b2).

As the crosslinking agent (B) used in the pressure-sensitive adhesive of the present invention, the core layer is made of a conventionally known isocyanate group-containing crosslinking agent, and the shell layer is made of a vinyl polymer having an isocyanate group and a polyalkylene oxide chain. A core-shell type crosslinking agent (B3) can be used. In particular, when the solvent constituting the pressure-sensitive adhesive of the present invention is an aqueous medium, the crosslinking agent (B3) has particularly good dispersibility with respect to the aqueous solvent, so that the crosslinking reaction proceeds efficiently and is excellent. It is preferable at the point which can provide removability.
As an isocyanate group containing crosslinking agent which forms the core layer of the said crosslinking agent (B3), the thing similar to what was illustrated as the said isocyanate group containing compound (b1), for example can be used. Moreover, as a vinyl polymer which forms the said shell layer, the thing similar to what was illustrated as said vinyl polymer (b3) can be manufactured.
The crosslinking agent (B3) is prepared by supplying and mixing the vinyl polymer (b3) produced by the same method as described above and the isocyanate group-containing compound (b1) in an aqueous medium. The group-containing compound (b1) can be produced by being emulsified with a vinyl polymer (b3) having a hydrophilic group.

  In the crosslinking agent (B3), the mass ratio of the isocyanate group-containing compound (b2) and the vinyl polymer (b3) having an alkylene oxide group and an isocyanate group is [(b2) / (b3)] = 30 / It is preferably configured in the range of 70 to 85/15, more preferably in the range of 50/50 to 80/20, and most preferably in the range of 60/40 to 80/20.

  In the crosslinking agent (B) used in the present invention, from the viewpoint of adjusting the removability of the pressure-sensitive adhesive, a conventionally known isocyanate crosslinking agent, specifically, the isocyanate group-containing compound (b1) is arbitrarily selected. It can also be used in combination in the range.

Next, the ionic compound (C) used in the present invention will be described.
The ionic compound (C) used in the present invention is an essential component for obtaining a pressure-sensitive adhesive capable of forming a pressure-sensitive adhesive layer having excellent antistatic properties.

  As the ionic compound (C), an organic ionic compound or an inorganic ionic compound can be used. These compounds may be used alone or in combination of two or more.

  As the organic ionic compound, it is preferable to use a salt that is liquid at room temperature, generally called an ionic liquid.

As the ionic liquid, one having an ionic conductivity of approximately 10 ⁻³ Scm ⁻¹ or more is preferably used in order to form an adhesive layer having excellent antistatic properties.

  As said ionic liquid, what is comprised from a cation and an anion can be used.

  As the cation component, for example, aliphatic, alicyclic, and alicyclic cations can be used. Specifically, imidazolium cation, pyridium cation, piperidinium cation, ammonium cation, sulfonium cation A phosphonium cation or the like can be used.

As the anion, Cl ⁻ , Br ⁻ , NCO ₃ ⁻ , CH ₃ COO ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , perfluoroalkanesulfonate, perfluoroalkanesulfonylimide, and the like can be used.

Among the ionic liquids described above, an imidazolium cation, a pyridium cation, a piperidinium cation as a cation component, a fluorine atom-containing imide anion as an anion component, particularly (CF ₃ SO ₂ ) ₂ N ⁻ , (C ₂ F ₅ SO _2). ) The use of a salt composed of ₂ N ⁻ prevents the adhesive from remaining on the surface of the optical member after the surface protective film of the present invention is peeled from the surface of the optical member, and provides a good antistatic property to the adhesive layer. It is preferable because it can impart the properties.

  The ionic liquid is preferably used in an amount of 0.01 to 10% by mass with respect to the total amount of the pressure-sensitive adhesive of the present invention, in order to impart good antistatic performance to the pressure-sensitive adhesive layer. It is more preferable to use in the range of ˜3 mass%.

  In addition, as the inorganic ionic compound, for example, an alkali metal salt composed of a cation and an anion can be used.

Examples of the cation constituting the alkali metal salt include alkali metals, such as Li ⁺ , Na ⁺ , K ^{+ and the} like. Among them, by using Li ⁺ as a cation component, the interaction with the alkylene oxide contained in the acrylic polymer (A) or the crosslinking agent (B) works effectively, and a good antistatic effect is exhibited. To preferred.

Examples of the anion paired with the cation include Cl ⁻ , Br ⁻ , I ⁻ , 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 - , and the like. Among these, it is preferable to use a compound containing a fluorine atom as an anion component because it does not cause adherend contamination and can impart good removability.

Among the alkali metal salts described above, the use of a salt composed of Li (CF ₃ SO ₂ ) ₂ N and Li (C ₂ F ₅ SO ₂ ) ₂ N in particular makes the surface protective film of the present invention an optical member. After peeling from the surface, the pressure-sensitive adhesive does not remain on the surface of the optical member, and good antistatic properties can be imparted to the pressure-sensitive adhesive layer, which is preferable.

  The ionic compound is preferably used in an amount of 0.01 to 10% by mass with respect to the total amount of the pressure-sensitive adhesive of the present invention, in order to impart good antistatic performance to the pressure-sensitive adhesive layer. It is more preferable to use in the range of 3 to 3% by mass.

  The pressure-sensitive adhesive of the present invention may contain other additives as necessary in addition to the above-described components.

  Examples of the additive include a crosslinking agent other than the crosslinking agent (B), specifically, an epoxy compound, a melamine resin, an aziridine compound, an isocyanate crosslinking agent having no polyalkylene oxide chain, light, heat, and the like. A monomer having two or more polymerizable unsaturated double bonds that can be polymerized can be used.

  As the additive, a crosslinking catalyst may be used for the purpose of promoting the reaction of the crosslinking agent.

  Examples of the additives include powders such as colorants, pigments, surfactants, plasticizers, tackifiers, low molecular weight polymers, surface smoothing agents, leveling agents, antioxidants, corrosion inhibitors, light Stabilizers, ultraviolet absorbers, polymerization inhibitors, silane coupling agents, inorganic or organic fillers, metal powders, particles, foils, and the like can be added as appropriate according to the intended use.

Next, the manufacturing method of the adhesive of this invention is demonstrated.
The pressure-sensitive adhesive of the present invention is prepared by, for example, mixing a mixture of a hydroxyl group-containing acrylic polymer (A) produced in the above-described method with an organic solvent solution and an ionic compound (C), and a crosslinking agent (B). It can be produced by stirring. Since the pressure-sensitive adhesive mixed with the cross-linking agent (B) proceeds with a cross-linking reaction, it is preferable to perform coating or the like immediately after the production of the pressure-sensitive adhesive.

  When the ionic compound (C) is a compound that is not liquid at normal temperature, it is preferable to use a compound that has been dissolved in advance using an organic solvent such as ethyl acetate.

  When the ionic compound (C) is the ionic liquid, the ionic liquid may be mixed into the polymer during the production of the acrylic polymer (A).

  The pressure-sensitive adhesive obtained by the above method can be used for pressure-sensitive adhesive layers constituting various pressure-sensitive adhesive films because it can form a pressure-sensitive adhesive layer having excellent antistatic properties without impairing coating workability. Can do.

  As said adhesive film, it can be used for the surface protection film for protecting the surface of optical members, such as a polarizing plate, an optical compensation film, a phase difference plate, a film for dicing, a back grind film, etc., for example. In particular, the surface protective film for the optical member is preferable because it has an adhesive layer that satisfies performance requirements from the industry.

  The adhesive film has an adhesive layer on one or both sides of a film or sheet made of plastic such as polyethylene terephthalate.

  Although there is no restriction | limiting in particular in the thickness of the adhesion layer of this adhesion film, 1-100 micrometers is preferable. When using as a surface protection film of an optical member especially, 5-30 micrometers is preferable.

  As a method for producing the pressure-sensitive adhesive film or the optical member surface protective film, for example, a mixture in which the acrylic polymer (A) and the ionic compound (C) are dissolved or dispersed in a solvent, and the crosslinking agent (B) There is a method in which the pressure-sensitive adhesive is coated on a plastic substrate and cured, immediately after the pressure-sensitive adhesive is mixed to produce the pressure-sensitive adhesive of the present invention.

  Moreover, the said adhesive film or optical member surface protective film can also be manufactured by the method of transcribe | transferring the adhesive layer produced previously to the plastic substrate surface.

  As the plastic substrate, it is preferable to use a sheet or film, for example, polyester such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyolefin, polyacrylate, polyvinyl chloride, polyethylene, polypropylene. It is preferable to use a sheet or film made of ethylene vinyl alcohol, polyurethane, polyamide, or polyimide. Although the said plastic base material changes with applications which use an adhesive film, it is preferable that it is a thickness of 10-100 micrometers in general.

  In addition, when the pressure-sensitive adhesive of the present invention is used for a surface protective film for an optical member, a higher level of antistatic property is required as the film, so that the plastic substrate is subjected to antistatic treatment. It is preferable to use it.

  Examples of the method for applying the pressure-sensitive adhesive of the present invention to one or both sides of the plastic substrate include a method using a roll coater, gravure coater, reverse coater, spray coater, air knife coater, die coater and the like.

  In addition, as a method of curing the pressure-sensitive adhesive after applying the pressure-sensitive adhesive on the plastic substrate, a method of curing for a certain period at room temperature may be used, but from the viewpoint of promoting the curing reaction, 30 ° C. You may cure in the range of -50 degreeC.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples.

[Process for surface protection film]
Each pressure-sensitive adhesive described later was applied to the surface of a 25 μm-thick polyethylene terephthalate film (release paper) that had been release-treated on the surface so that the film thickness after drying was 20 μm, and dried at 100 ° C. for 2 minutes. Thereafter, a polyethylene terephthalate film having a thickness of 38 μm was bonded to the surface made of the pressure-sensitive adhesive, and a surface protective film was obtained by aging in an environment at 23 ° C. for 7 days.

[Evaluation method of antistatic properties]
A test piece was prepared by cutting the surface protective film prepared by the above method into a size of 50 mm × 50 mm. The release paper was peeled from the test piece and left in an atmosphere of 23 ° C. × 50% RH for 1 day. The surface electrical resistivity (Ω / □) of the adhesive layer after standing is measured using an ultra-high resistance / microammeter (manufactured by Advantest Co., Ltd.). Based on this value, the antistatic performance of the adhesive is determined. evaluated. It can be said that the adhesive having a surface electrical resistivity of 1 × 10 ¹⁰ Ω / □ or more and less than 5.0 × 10 ¹⁰ Ω / □ is practically sufficient. Moreover, the adhesive which is 5.0 × 10 ¹⁰ Ω / □ or more and less than 1 × 10 ¹¹ Ω / □ is at a level that can be used practically although it is slightly inferior. It is hard to say that a material having a value of 1 × 10 ¹¹ Ω / □ or more is sufficient for practical use.

[Measurement method of adhesive strength]
The release paper was peeled from the surface protective film prepared by the above method, and the 180-degree peel strength was measured according to JIS Z-0237 for the one attached to the surface of the polarizing plate. It is practically preferable that the peel strength is approximately 0.15 N / 25 mm or less.

[Measurement method of removability]
When the surface protective film was peeled off from the polarizing plate surface according to the above [Measurement method of adhesive strength], the state of the adhesive residue on the polarizing plate surface was visually evaluated.
○: Good (no adhesive residue)
Δ: Partial adhesive residue (with adhesive residue at less than 20% of the pasted area)
×: Defect (there is adhesive residue at 20% or more of the pasted part)

[Measurement method of degree of change]
The viscosity at 23 ° C. of the pressure-sensitive adhesive of the present invention was measured using a BM viscometer manufactured by Toki Sangyo Co., Ltd. at a rotation speed of 6 rpm and 60 rpm, respectively. Using the viscosity at 6 rpm and the viscosity at 60 rpm, the wrinkle degree was determined based on the following calculation formula.
Degree of change = (6 rpm viscosity / 60 rpm viscosity)

[Coating workability evaluation method]
When the pressure-sensitive adhesive of the present invention was applied at a rate of 30 m / min onto a 25 μm-thick polyethylene terephthalate film having a thickness of 20 μm after drying using a roll coater, The smoothness of the coating surface was visually evaluated.
○: Good (smooth coated surface)
△: Partially defective (coating surface with relatively poor viscosity during coating but relatively smooth)
×: Defective (viscosity is poor at the time of coating, streaks are observed and it cannot be said that the coated surface is smooth)

[Method for Producing Acrylic Polymer (A-1)]
A reaction vessel equipped with a stirrer, reflux condenser, nitrogen inlet tube, and thermometer was charged with 907 parts by mass of 2-ethylhexyl acrylate, 90 parts by mass of 2-hydroxyethyl acrylate, 3 parts by mass of acrylic acid, and 1180 parts by mass of ethyl acetate. While stirring, the temperature was raised to 70 ° C. while blowing nitrogen. Thereafter, 20 parts by mass (solid content: 5% by mass) of an azobisisobutyronitrile solution previously dissolved in ethyl acetate was added. Then, after holding for 8 hours at 70 ° C. with stirring, the contents were cooled and filtered through a 200 mesh wire mesh. An acrylic polymer (A-1) solution having a nonvolatile content of 45.4% by mass and a viscosity of 1600 mPa · s was obtained.

[Method for producing acrylic polymer (A-2)]
In a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, and a thermometer, 720 parts by mass of 2-ethylhexyl acrylate, 70 parts by mass of n-butyl allylate, methoxyethylene glycol methacrylate (hereinafter referred to as MPEGMA-1; ethylene). About 9 mol of oxide adduct) 100 parts by mass, 110 parts by mass of 2-hydroxyethyl acrylate, and 1180 parts by mass of ethyl acetate were charged, and the temperature was raised to 70 ° C. while blowing nitrogen under stirring. Thereafter, 20 parts by mass (solid content: 5% by mass) of an azobisisobutyronitrile solution previously dissolved in ethyl acetate was added. Then, after holding for 8 hours at 70 ° C. with stirring, the contents were cooled and filtered through a 200 mesh wire mesh. An acrylic polymer (A-2) solution having a nonvolatile content of 45.2% by mass and a viscosity of 1620 mPa · s was obtained.

[Method for producing acrylic polymer (A-3)]
In a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, and a thermometer, 548 parts by mass of 2-ethylhexyl acrylate, 250 parts by mass of n-butyl allylate, 150 parts by mass of MPEGMA-1, and 50 of 4-hydroxybutyl acrylate Part by mass, 2 parts by mass of acrylic acid, and 1180 parts by mass of ethyl acetate were charged, and the temperature was raised to 70 ° C. while blowing nitrogen under stirring. Thereafter, 20 parts by mass (solid content: 5% by mass) of an azobisisobutyronitrile solution previously dissolved in ethyl acetate was added. Then, after holding for 8 hours at 70 ° C. with stirring, the contents were cooled and filtered through a 200 mesh wire mesh. An acrylic polymer (A-3) solution having a nonvolatile content of 45.0% by mass and a viscosity of 1320 mPa · s was obtained.

[Method for producing acrylic polymer (A-4)]
In a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, and a thermometer, 477 parts by mass of 2-ethylhexyl acrylate, 150 parts by mass of n-butyl allylate, 300 parts by mass of MPEGMA-1, and 70 of 2-hydroxyethyl acrylate 70 Part by mass, 3 parts by mass of acrylic acid, and 1180 parts by mass of ethyl acetate were charged, and the temperature was raised to 70 ° C. while blowing nitrogen under stirring. Thereafter, 20 parts by mass (solid content: 5% by mass) of an azobisisobutyronitrile solution previously dissolved in ethyl acetate was added. Then, after holding for 8 hours at 70 ° C. with stirring, the contents were cooled and filtered through a 200 mesh wire mesh. An acrylic polymer (A-4) solution having a nonvolatile content of 45.1% by mass and a viscosity of 1820 mPa · s was obtained.

[Method for producing acrylic polymer (A-5)]
In a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, and a thermometer, 538 parts by mass of 2-ethylhexyl acrylate, 350 parts by mass of n-butyl allylate, methoxyethylene glycol methacrylate (hereinafter referred to as MPEGMA-2, ethylene). About 23 mol of oxide adduct) 40 parts by mass, 70 parts by mass of 4-hydroxybutyl acrylate, and 1180 parts by mass of ethyl acetate were charged, and the temperature was raised to 70 ° C. while blowing nitrogen under stirring. Thereafter, 20 parts by mass (solid content: 5% by mass) of an azobisisobutyronitrile solution previously dissolved in ethyl acetate was added. Then, after holding for 8 hours at 70 ° C. with stirring, the contents were cooled and filtered through a 200 mesh wire mesh. An acrylic polymer (A-5) solution having a nonvolatile content of 45.2% by mass and a viscosity of 1120 mPa · s was obtained.

[Method for producing acrylic polymer (A-6)]
In a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, and a thermometer, 796 parts by mass of 2-ethylhexyl acrylate and 150 masses of methoxyethylene glycol methacrylate (hereinafter referred to as MPEGMA-2; about 23 mol of ethylene oxide adduct) Part, 50 parts by mass of 2-hydroxyethyl acrylate, and 1180 parts by mass of ethyl acetate, and the temperature was raised to 70 ° C. with stirring while blowing nitrogen. After 1 hour, 20 parts by mass (solid content 5% by mass) of an azobisisobutyronitrile solution previously dissolved in ethyl acetate was added. Then, after holding for 8 hours at 70 ° C. with stirring, the contents were cooled and filtered through a 200 mesh wire mesh. An acrylic polymer (A-6) solution having a nonvolatile content of 45.0% by mass and a viscosity of 2800 mPa · s was obtained.

[Method for producing acrylic polymer (A-7)]
In a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, and a thermometer, 468 parts by mass of 2-ethylhexyl acrylate, 130 parts by mass of n-butyl allylate, methoxyethylene glycol methacrylate (hereinafter referred to as MPEGMA-2, ethylene). About 23 mol of oxide adduct) 350 parts by mass, 50 parts by mass of 4-hydroxybutyl acrylate, and 1180 parts by mass of ethyl acetate were charged, and the temperature was raised to 70 ° C. while blowing nitrogen under stirring. Thereafter, 20 parts by mass (solid content: 5% by mass) of an azobisisobutyronitrile solution previously dissolved in ethyl acetate was added. Then, after holding for 8 hours at 70 ° C. with stirring, the contents were cooled and filtered through a 200 mesh wire mesh. An acrylic polymer (A-7) solution having a nonvolatile content of 45.4% by mass and a viscosity of 2220 mPa · s was obtained.

[Method for producing crosslinking agent (B1-1)]
In a reaction vessel equipped with a stirrer, reflux condenser, nitrogen inlet tube and thermometer, 13 parts by mass of diethylene glycol diethyl ether, 24 parts by mass of methoxypolyethylene glycol (containing 12 oxyethylene units on average per molecule), hexamethylene diisocyanate -Based isocyanurate type polyisocyanate "Bernock DN-980S" (Dainippon Ink & Chemicals, Inc.); isocyanate group content 21 mass%, average number of isocyanate groups present in one molecule is about 3.6, nonvolatile content 100 (Mass%) 100 mass parts was prepared, and it heated up at 90 degreeC over 30 minutes. Thereafter, the reaction is carried out at 90 ° C. for 6 hours, and the isocyanate-based crosslinking modified with methoxypolyethylene glycol having a nonvolatile content of 90% by mass, an NCO content of 14.0% by mass, and an ethylene oxide group content of 16.4% by mass. The agent (B1-1) was obtained.

[Method for producing crosslinking agent (B1-2)]
In a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, and a thermometer, 16 parts by mass of diethylene glycol diethyl ether, 50 parts by mass of methoxypolyethylene glycol (containing 35 average oxyethylene units per molecule), Bernock DN- 100 parts by mass of 980S was charged and heated to 90 ° C. over 30 minutes. Thereafter, the reaction was carried out at 90 ° C. for 6 hours, and isocyanate-based crosslinking modified with methoxypolyethylene glycol having a nonvolatile content of 90% by mass, an NCO content of 11.8% by mass, and an ethylene oxide group content of 29.4% by mass. An agent (B2-1) was obtained.

  [Method for producing crosslinking agent (B2-3)]

In a four-necked flask equipped with a stirrer, a thermometer, a cooling tube, and a nitrogen introduction tube, 429 parts by mass of diethylene glycol diethyl ether was charged, and the temperature was raised to 110 ° C. under a nitrogen stream. Thereafter, 500 parts by mass of MPEGMA-1, 300 parts by mass of methyl methacrylate, 50 parts by mass of 2-hydroxyethyl methacrylate (hereinafter abbreviated as 2-HEMA), 150 parts by mass of cyclohexyl methacrylate (hereinafter abbreviated as CHMA). Then, a mixed solution consisting of 45 parts by mass of t-butylperoxy-2-ethylhexanoate and 5 parts by mass of t-butylperoxybenzoate was added dropwise over 5 hours. After dropping, the reaction was carried out at 110 ° C. for 9 hours to obtain a solution of an active hydrogen group-containing vinyl polymer having a nonvolatile content of 70% by mass.
A 4-necked flask was charged with 200 parts by weight of Bernock DN-980S and 100 parts by weight of the active hydrogen-containing group-containing vinyl polymer solution, heated to 90 ° C. under a nitrogen stream, and then stirred at the same temperature for 6 hours. Reacted. And the non volatile matter contains 90 mass% and NCO group content rate containing the vinyl polymer (b2-1) which is the reaction material of the said Bernock DN-980S and the said containing vinyl polymer, and the said Bernock DN-980S. Of 13 mass% and an ethylene oxide group content of 19.3 mass% was obtained as a crosslinking agent (B2-3).

[Example 1]
A container is charged with 100 parts by mass of the acrylic polymer (A-1) solution and 1.125 parts by mass of 1-methyl-3-methylpyridinium trifluoromethanesulfonylimide (hereinafter referred to as ionic compound (C1-1)). , Stirred and mixed. Thereafter, 6 parts by mass of the cross-linking agent (B1-1) was added and stirred and mixed so as to be uniform. Then, the adhesive 1 was obtained by filtering with a 100 mesh metal-mesh.

[Example 2]
In a container, 100 parts by mass of the acrylic polymer (A-2) solution and 0.45 parts by mass of lithium trifluoromethanesulfonylimide (hereinafter referred to as ionic compound (C2-3)) were charged and mixed with stirring. Thereafter, 7 parts by mass of the cross-linking agent (B1-1) was added and stirred and mixed so as to be uniform. Then, the adhesive 2 was obtained by filtering with a 100 mesh metal-mesh.

[Example 3]
In a container, 100 parts by mass of the acrylic polymer (A-3) solution and 0.45 parts by mass of the ionic compound (C1-1) were charged and mixed with stirring. Thereafter, 2.5 parts by mass of the crosslinking agent (B1-1) was added and stirred and mixed so as to be uniform. Then, the adhesive 3 was obtained by filtering with a 100 mesh metal-mesh.

[Example 4]
In a container, 100 parts by mass of the acrylic polymer (A-4) solution and 0.225 parts by mass of the ionic compound (C1-1) were charged and mixed with stirring. Thereafter, 4.5 parts by mass of the cross-linking agent (B1-1) was added and stirred and mixed so as to be uniform. Then, the adhesive 4 was obtained by filtering with a 100 mesh metal-mesh.

[Example 5]
In a container, 100 parts by mass of the acrylic polymer (A-5) solution and 0.45 parts by mass of the ionic compound (C1-1) were charged and mixed with stirring. Thereafter, 3.5 parts by mass of the cross-linking agent (B1-1) was added and stirred and mixed so as to be uniform. Then, the adhesive 5 was obtained by filtering with a 100 mesh metal-mesh.

[Example 6]
In a container, 100 parts by mass of the acrylic polymer (A-6) solution and 0.675 parts by mass of the ionic compound (C2-3) were charged and mixed with stirring. Thereafter, 3.25 parts by mass of the cross-linking agent (B1-1) was added and stirred and mixed so as to be uniform. Then, the adhesive 6 was obtained by filtering with a 100 mesh metal-mesh.

[Example 7]
In a container, 100 parts by mass of the acrylic polymer (A-1) solution and 0.9 part by mass of 1-methyl-3-methylpyridinium trifluoromethanesulfonate (hereinafter referred to as ionic compound (C1-2)) are charged, Stir and mix. Thereafter, 7 parts by mass of the cross-linking agent (B1-2) was added and stirred and mixed so as to be uniform. Then, the adhesive 7 was obtained by filtering with a 100 mesh metal-mesh.

[Example 8]
In a container, 100 parts by mass of the acrylic polymer (A-3) solution and 0.9 parts by mass of the ionic compound (C2-3) were charged and mixed with stirring. Thereafter, 3 parts by mass of the cross-linking agent (B1-2) was added and stirred and mixed so as to be uniform. Then, the adhesive 8 was obtained by filtering with a 100 mesh metal-mesh.

[Example 9]
In a container, 100 parts by mass of the acrylic polymer (A-3) solution and 0.675 parts by mass of the ionic compound (C2-3) were charged and mixed with stirring. Thereafter, 3 parts by mass of the cross-linking agent (B2-3) was added and stirred and mixed so as to be uniform. Then, the adhesive 9 was obtained by filtering with a 100 mesh metal-mesh.

[Example 10]
In a container, 100 parts by mass of the acrylic polymer (A-3) solution and 0.45 parts by mass of the ionic compound (C1-1) were charged and mixed with stirring. Thereafter, 1.75 parts by mass of the cross-linking agent (B1-1) was added and stirred and mixed so as to be uniform. Then, the adhesive 10 was obtained by filtering with a 100 mesh metal-mesh.

[Comparative Example 1]
In a container, 100 parts by mass of the acrylic polymer (A-1) solution and 1.35 parts by mass of the ionic compound (C1-1) were charged and mixed with stirring. Thereafter, 3.6 parts by mass of the cross-linking agent Vernock DN-980S was added and stirred and mixed to be uniform. Then, the adhesive 11 was obtained by filtering with a 100 mesh metal-mesh.

[Comparative Example 2]
In a container, 100 parts by mass of the acrylic polymer (A-5) solution and 0.45 parts by mass of the ionic compound (C2-3) were charged and mixed with stirring. Thereafter, 2.7 parts by mass of the crosslinking agent Vernock DN-980S was added, and the mixture was stirred and mixed so as to be uniform. Then, the adhesive 12 was obtained by filtering with a 100 mesh metal-mesh.

[Comparative Example 3]
In a container, 100 parts by mass of the acrylic polymer (A-7) solution and 0.225 parts by mass of the ionic compound (C1-1) were charged and mixed with stirring. Thereafter, 2.025 parts by mass of the crosslinking agent Vernock DN-980S was added and mixed with stirring so as to be uniform. Then, the adhesive 13 was obtained by filtering with a 100 mesh metal-mesh.

The official names of the abbreviations used in Tables 1 and 2 are shown below. Moreover, the blending ratios of the acrylic polymer (A), the crosslinking agent (B), and the ionic compound (C) described in the table are all parts by mass based on the solid content not containing a solvent.
DN-980S; Bernock DN-980S (hexamethylene diisocyanate-based isocyanurate type polyisocyanate, manufactured by Dainippon Ink & Chemicals, Inc., isocyanate group content 21 mass%, average number of isocyanate groups present in one molecule is about 3 .6, 100% by mass of non-volatile content)
[NCO / OH]: molar ratio of isocyanate group (NCO) of the crosslinking agent to hydroxyl group (OH) of the acrylic polymer

Claims (7)

Hydroxyl group-containing acrylic polymer (A), cross-linking agent (B2) comprising a vinyl polymer having an isocyanate group and a polyalkylene oxide chain, and cation components such as imidazolium cation, pyridium cation, piperidium cation, ammonium cation An ionic liquid composed of a sulfonium cation or a phosphonium cation and, as an anion component, Br ⁻ , NCO ₃ ⁻ , CH ₃ COO ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , perfluoroalkanesulfonate or perfluoroalkanesulfonylimide, Or the adhesive which contains the alkali metal salt (C) which uses the compound containing a fluorine atom as an anion component. The crosslinking agent (B 2) is a crosslinking agent (B 2) adhesive of the polyalkylene oxide chains having 5 to 50 mass%, according to claim 1, wherein the total amount. Ratio [NCO / OH] of the number of moles of isocyanate group (NCO) of the crosslinking agent (B 2 ) and the number of moles of hydroxyl group (OH) of the hydroxyl group-containing acrylic polymer (A) is 0.2 to The pressure-sensitive adhesive according to claim 1, which is in the range of 1.5. The pressure-sensitive adhesive according to claim 1, wherein the hydroxyl group-containing acrylic polymer (A) has a polyalkylene oxide chain and a carboxyl group. The adhesive film in which the adhesion layer which consists of an adhesive in any one of Claims 1-4 was formed in the single side | surface or both surfaces of a plastic base material. The surface protection film for optical members in which the adhesion layer which consists of adhesion in any one of Claims 1-4 was formed in the single side | surface or both surfaces of a plastic base material. In the solvent, the hydroxyl group-containing acrylic polymer (A) and the cation component include imidazolium cation, pyridium cation, piperidinium cation, ammonium cation, sulfonium cation, or phosphonium cation, and the anion component includes Br ⁻ , NCO ₃ ⁻ , Alkali metal salts (C) containing an ionic liquid composed of CH ₃ COO ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , perfluoroalkanesulfonate or perfluoroalkanesulfonylimide, or a compound containing a fluorine atom as an anionic component A pressure-sensitive adhesive was prepared by mixing a mixture in which the polymer was dissolved or dispersed and a cross-linking agent (B2) made of a vinyl polymer having an isocyanate group and a polyalkylene oxide chain. Apply to Pressure-sensitive adhesive sheet or the optical member manufacturing method for the surface protective film, wherein the curing.