JP2010126707A - Protect film for optical member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a protect film for optical members, of which the composition of an acrylic polymer (A) and the composition of an acrylic polymer (B) have identity and which is excellent in antistatic properties, has high transparency, and is hardly contaminated. <P>SOLUTION: The protect film for optical members is formed by laminating a pressure-sensitive adhesive layer to a base film. The pressure-sensitive adhesive layer comprises 100 pts.wt. of an acrylic polymer (A) formed by copolymerizing an alkyl (meth)acrylate with a functional group-containing monomer copolymerizable therewith and 2-10 pts.wt. of an acrylic polymer (B) having a quaternary ammonium group at its side chain and a weight average molecular weight of 500-3,000. The acrylic polymer (B) contains repeating units having quaternary ammonium groups at its side chains, the content of the repeating units being 7-30 wt.% of the total amount of the acrylic polymer (B). In the total monomers constituting the allylic polymer (B), at least one of an alkyl acrylate, being the same as an alkyl acrylate used for copolymerization for forming an acrylic polymer (A), and at least one of a functional group-containing monomer, being the same as the functional group-containing monomer, are contained, the sum amount of the alkyl acrylate and the functional group-containing monomer being 70-90 wt.%. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a protect film used for protecting an optical member such as a liquid crystal element. More specifically, the present invention relates to a protective film that protects an optical member such as a liquid crystal element, and relates to a protective film that has excellent antistatic properties and excellent properties such as transparency.

In recent years, thin display devices such as liquid crystal display devices and plasma displays have been widely used in place of CRTs and the like.
Such a thin display device has a multi-layered structure of thin films having various functions when viewed in cross section. In order to prevent damage in the manufacturing process, a protective film is attached to the surface of the display device having a thin film multilayer structure having various functions.

At the same time, since the display device manufactured in this way is easily charged in the manufacturing process, it is necessary to remove static electricity accumulated in the display device charged in this way.
Conventionally, a protective film is adhered to the surface of a thin display device so that the device is protected and static electricity is not accumulated.

This protective film has a configuration in which an adhesive layer containing a conductive substance is laid on one surface of a transparent film. Here, in consideration of transparency, a surfactant type conductive material having ionicity is often used as the conductive material. However, the surfactant-type conductive material thus pressed is not dissolved in the pressure-sensitive adhesive used as the base material of the pressure-sensitive adhesive layer, but is present in a finely dispersed form. In addition, the conductive material sometimes bleeds onto the surface of the pressure-sensitive adhesive layer, thereby contaminating the display device as the adherend. In addition, as the conductive material moves, the charging characteristics may change with time. For example, Patent Document 1 (Japanese Patent Laid-Open No. 2007-297446) states that “an acrylic copolymer having a SP value of 8.80 to 9.00, which is a mixture of acrylic copolymers having different amounts of reactive hydroxyl groups. Copolymer mixture (A), isocyanate compound (B) and methyl ethyl ketone (MEK)
An acrylic pressure-sensitive adhesive containing a quaternary ammonium salt (C) that is soluble in 2) and has 2 or 3 molecules in the molecule. Is disclosed. However, as described in paragraph [0016] of Patent Document 1, in the pressure-sensitive adhesive described in Patent Document 1, the antistatic component bleeds from a crosslinked structure formed by a hydroxyl group and an isocyanate compound. Thus, the antistatic property is expressed. By bleeding the antistatic component in this way, this pressure-sensitive adhesive can be given antistatic performance. However, fine dust or the like may adhere to the bleed antistatic component, resulting in contamination of the display device. It may lead to

By the way, regarding the problem caused by bleeding of the antistatic component, “(A) flexible polymer 99.5-50” described in claim 1 of Patent Document 2 (Japanese Patent Laid-Open No. 9-111129).
Parts by weight, (B) an α-olefin structural unit represented by the following specific general formula (I) and / or a (meth) acrylate structural unit represented by the following specific general formula (II):
65 mol% and one kind of quaternary cation selected from the group represented by (III), (IV), (V), (VI), (VII) and (VIII) represented by a specific general formula 0.5 to 50 parts by weight of a quaternary cation group-containing polymer having a weight average molecular weight of 1000 to 300,000 consisting of 90 to 35 mol% of salt structural units, and (C) having a weight average molecular weight of 500 to 1,000,000. A thermoplastic polymer composition comprising 0 to 20 parts by weight of polyethylene glycol. In the invention, the monomer containing a quaternary cation group can be prevented by being combined with a specific (meth) acryl structural unit (II) and contained in a thermoplastic polymer composition. Yes.

  In Patent Document 2, a copolymer of a quaternary cation salt structural unit and a (meth) acrylate structural unit represented by a specific general formula (II) is blended in the thermoplastic polymer (A). The copolymer having a quaternary cation salt structure is very incompatible with a base polymer such as the thermoplastic polymer (A). Therefore, paragraph [0069] of Patent Document 2 describes that the quaternary cation salt-containing polymer to be used is selected depending on the type of the thermoplastic polymer to be used. As an example, the thermoplastic polymer is styrene. In the case of a resin, it is described that it is preferable to use a quaternary cation salt-containing polymer having a styrene structural unit. That is, Patent Document 2 describes that an ammonium polymer can be added as an antistatic agent to a thermoplastic resin such as an acrylic polymer, and the relationship between the thermoplastic resin used at this time and the ammonium polymer. Is only disclosed that they are preferably the same polymer species.

  As described in Patent Document 2, by making the thermoplastic resin and the ammonium polymer into the same polymer species, that is, for example, by making both of them an acrylic polymer or a styrene polymer, mutual dissolution of both polymers Although the solubility is improved, the solubility of the ammonium polymer in the thermoplastic resin which is the base polymer is still not good, and the ammonium polymer cannot be uniformly dissolved in the thermosetting resin.

For this reason, in the resin composition obtained by patent document 2, transparency may fall, and also there exists a problem that antistatic performance is not constant.
JP 2007-297446 A Japanese Patent Laid-Open No. 9-111129

  An object of the present invention is to provide a protective film for electronic parts that has excellent antistatic performance, high transparency, and is hardly contaminated.

The protective film for optical members of the present invention is an acrylic polymer (A) formed by copolymerizing a (meth) acrylic acid alkyl ester and a functional group-containing monomer copolymerizable therewith, with respect to 100 parts by weight. Acrylic polymer (B) having a quaternary ammonium group in the side chain and having a weight average molecular weight of 500 to 3000: an adhesive layer composed of 2 to 10 parts by weight is laminated on a base film,
The acrylic polymer (B) is
An acrylic polymer containing 7 to 30% by weight of a repeating unit having a quaternary ammonium group in the side chain in the whole acrylic polymer (B) and constituting the allyl polymer (B). 70-90% by weight in total of one or more kinds of alkyl acrylates identical to the alkyl acrylate copolymerized in (A) and one or more kinds of functional group-containing monomers identical to the functional group-containing monomers It is characterized by being a copolymer copolymerized in proportion.

Thus, in the protective film for an optical member of the present invention, the polymer skeleton forming the basic skeleton of the acrylic polymer (B) containing an ammonium group is the same as the composition of the acrylic polymer (A) serving as the base material. Therefore, the acrylic polymer (B) containing an ammonium group exhibits very good solubility in the acrylic polymer (A) as a base material. This acrylic polymer (A) containing an acrylic polymer (B) containing an ammonium group forms an adhesive layer of a protective film for an optical member, and contains an acrylic polymer (B) containing an ammonium group. Is well dispersed in the acrylic polymer (A), the protective film for optical members of the present invention is not unevenly distributed in antistatic performance, and specifically, the peel voltage is 0.0 V over the entire film. As described above, since the protective film for optical members of the present invention has excellent antistatic performance, the surrounding dust is not attracted by static electricity, and the glass transition temperature of the pressure-sensitive adhesive layer is set to be somewhat high. Therefore, the protective film for optical members of the present invention or the display device as the adherend is hardly contaminated by surrounding dust or the like. The transparency of the anti-blocking agent is high, and the optical protective film of the present invention has good transparency.

  As described above, the protective film for an optical member of the present invention has a basic skeleton other than the structural unit having an ammonium group that constitutes the acrylic polymer (B) containing a quaternary ammonium group that is deeply involved in antistatic properties. The main component of the adhesive has almost the same structure as the basic skeleton of the acrylic polymer (A). For this reason, since the main skeleton of the acrylic polymer (B) is composed of the same component units as those constituting the main skeleton of the acrylic polymer (A) which is the main agent of the pressure-sensitive adhesive, the acrylic polymer ( The main skeletons of A) and the acrylic polymer (B) are almost the same, and both have extremely high compatibility. That is, it becomes extremely difficult to distinguish the acrylic polymer (A) from the acrylic polymer (B) at the main skeleton. As a result, even if the quaternary ammonium group is introduced into the side chain of the acrylic polymer (B), the acrylic polymer (A) and the acrylic polymer (B) having the same main chain structure are mixed. As a result, a highly uniform pressure-sensitive adhesive composition is formed.

  And the composition which consists of this acrylic polymer (A) and acrylic polymer (B) has the ammonium group for preventing electrification uniformly distributed over the whole, and has very excellent antistatic performance . Further, since the film is not charged by the antistatic action, the film or the display device is not contaminated by dust or the like.

  Moreover, since the compatibility of the acrylic polymer (A) and the acrylic polymer (B) is good, the adhesive layer of the protective film for optical members is also transparent, so that the transparency of the entire film is not impaired.

Next, the protective film for optical members of the present invention will be specifically described.
The protect film for optical members of the present invention is a laminate having a structure in which an adhesive layer is laminated on at least a base film.

Since the base film used here is light transmissive and has a function of protecting the optical member, a transparent resin film is usually used. Examples of such transparent resin films include (meth) acrylic resin films, polyalkylene terephthalate films such as polyethylene terephthalate, polycarbonate films, and α-olefin (co) polymer films.

The thickness of such a base film can be appropriately set according to the optical member to be protected, but is usually within the range of 10 to 150 μm, preferably 20 to 40 μm. A film having a thickness below the lower limit of the thickness is not suitable for the purpose of the present invention to protect the optical member because it is difficult to say that it has sufficient strength. In addition, the upper limit of the film does not need to be set in particular in terms of protecting the optical member. However, a film exceeding the above range often does not have sufficient flexibility, and is intended to be protected. It may not be possible to follow the change in the shape of the optical member.

  The protective film for optical parts of the present invention is usually colorless and transparent. However, when the optical member is actually used, the optical member protective film is temporarily adhered to the optical member for protection. In applications where it is necessary to clarify the presence of the protective film, such as when the protective film is peeled off, a colored film can be used as the base film. In some cases, the visible light transmittance of the substrate film may be lower than the above range.

  The protective film for optical parts according to the present invention comprises an acrylic polymer (A) on at least one surface, usually one surface of the base film as described above, and an acrylic polymer having a specific ammonium group in the side chain. An adhesive layer comprising (B) is formed.

The acrylic polymer (A) is generally formed from a (meth) acrylic acid alkyl ester and a polymerizable monomer having a functional group such as a hydroxyl group or a carboxyl group.
The (meth) acrylic acid alkyl ester used here has an alkyl group having 1 to 18 carbon atoms, preferably 1 to 8 carbon atoms. This alkyl group may be linear or branched.

Examples of such (meth) acrylic acid alkyl esters include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, and n-butyl (meth) acrylate. N-pentyl (meth) acrylate, n-hexyl (meth) acrylate, n-octyl (meth) acrylate, n-nonyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, and styryl (meth) ) (Meth) acrylates having linear alkyl groups such as acrylates;
Branches such as iso-propyl (meth) acrylate, iso-butyl (meth) acrylate, tert-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, and t-butyl (meth) acrylate (Meth) acrylic acid alkyl ester having an alkyl group;
Examples include isobornyl (meth) acrylate and (meth) acrylic acid alkyl ester having a cyclic alkyl group such as cyclohexyl (meth) acrylate. These can be used alone or in combination.

Examples of the hydroxyl group-containing monomer that forms the acrylic polymer (A) that is a functional group-containing monomer used in the present invention together with the (meth) acrylic monomer as described above include 2-hydroxyethyl (meth) acrylate, (Meth) acrylic acid-2-hydroxypropyl, (meth) acrylic acid-4-hydroxydibutyl, monoester of (meth) acrylic acid and polypropylene glycol or polyethylene glycol, and lactones and (meth) acrylic acid-2 Mention may be made of hydroxyl group-containing vinyl compounds such as adducts with -hydroxyethyl. These can be used alone or in combination.

  Furthermore, examples of the carboxyl group-containing polymer that forms an acrylic polymer that is a functional group-containing monomer used in the present invention together with the (meth) acrylic monomer as described above include (meth) acrylic acid, itaconic acid, and crotonic acid. , Maleic acid, and fumaric acid. These can be used alone or in combination.

The acrylic polymer (A) as described above has (meth) acrylic acid when the total copolymerization amount of the (meth) acrylic acid alkyl ester and the polymerizable monomer having a functional group is 100 parts by weight. The copolymerization is carried out so that the copolymerization amount of the alkyl ester is usually in the range of 60 to 99 parts by weight, preferably 70 to 98 parts by weight. Therefore, the polymerization amount of the polymerizable monomer having a functional group copolymerized in the acrylic polymer (A) is usually 40 to 0.1 parts by weight, preferably 30 to 2 parts by weight.

  Further, when a hydroxyl group-containing polymerizable monomer and a carboxyl group-containing polymerizable monomer are used as the polymerizable monomer having a functional group, the hydroxyl group-containing polymerizable monomer and the carboxyl group-containing polymerizable monomer are used. The body is used in a weight ratio, usually in an amount in the range of 70:30 to 99.5: 0.5, preferably in a ratio in the range of 90:10 to 99: 1.

  The acrylic polymer (A) used in the present invention is basically a copolymer of monomers as described above, but within the range not impairing the properties of the acrylic polymer (A). In addition, a part of the alkyl (meth) acrylate, specifically, usually 40% by weight or less, preferably 30% by weight or less of the amount of the (meth) acrylic acid alkyl ester may be replaced with other monomers. . Examples of other monomers that can be used in place of the acrylic polymer (A) are alkylene glycol alkoxyalkyl acrylates such as ethoxydiethylene glycol acrylate; and methoxy acrylate and ethoxy acrylate. Mention may be made of alkoxy acrylates. Even if the acrylic polymer (A) used in the present invention is copolymerized with the component unit derived from the above compound in an amount within the above-mentioned range, there is no significant variation in the properties of the acrylic polymer (A). These can be regarded as equivalent to the (meth) acrylic acid alkyl ester constituting the acrylic polymer (A) used here.

  The weight average molecular weight measured using gel permeation chromatography (GPC) of the acrylic polymer (A) having the above-described configuration is usually in the range of 100,000 to 2,000,000, preferably 200,000 to 1,500,000. It is in the range. The glass transition temperature (Tg) of the acrylic polymer (A) is usually in the range of −70 to less than + 30 ° C., preferably in the range of −70 to 0 ° C.

  The acrylic polymer (A) as described above can be produced by a method such as a solution polymerization method, a bulk polymerization method, an emulsion polymerization method or a seed polymerization method. In the present invention, the acrylic polymer (A) is particularly produced by a solution polymerization method. It is preferable.

  When the acrylic polymer (A) is produced by a solution polymerization method, generally, a reaction vessel provided with at least a stirring device, a reflux device, and a sealing means capable of replacing the air inside with an inert gas is used. After replacing the air in the reaction vessel with an inert gas such as nitrogen gas, the reaction components are added to the reaction solvent filled in the reaction vessel and stirred under heating. Next, while continuing stirring, a polymerization initiator is added to the reaction solution little by little, and the reaction is performed at a predetermined temperature. The reaction as described above is usually an exothermic reaction, and the reaction proceeds with the addition of a polymerization initiator and the temperature of the reaction solution increases. Therefore, the reaction solution is cooled or heated so that the reaction temperature becomes constant. In addition, since the weight average molecular weight of the obtained resin varies depending on the reaction temperature, the weight average molecular weight of the resin to be obtained often varies depending on the boiling point of the reaction solvent used.

  In the present invention, the weight average molecular weight of the acrylic polymer (A) is usually in the range of 100,000 to 2,000,000, preferably 200,000 to 1,500,000 as described above, and the weight of the acrylic polymer (A). In order to bring the average molecular weight into the above range, it is preferable to use an organic solvent having a boiling point in the range of 40 to 120 ° C.

Examples of such organic solvents include aromatic carbonization such as benzene, toluene, ethylbenzene, N-propylbenzene, t-butylbenzene, o-xylene, m-xylene, p-xylene, tetralin, decalin and aromatic naphtha. Hydrogens;
Aliphatic or alicyclic hydrocarbons such as N-hexane, N-heptane, N-octane, i-octane, N-decane, dipentene, petroleum spirit, petroleum naphtha and turpentine oil;
Esters such as ethyl acetate, N-butyl acetate, N-amyl acetate, 2-hydroxyethyl acetate, 2-butoxyethyl acetate, 3-methoxybutyl acetate and methyl benzoate;
Ketones such as acetone, methyl ethyl ketone, methyl-i-butyl ketone, isophorone, cyclohexanone and methylcyclohexanone;
Glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether and diethylene glycol monobutyl ether;
Examples include alcohols such as methyl alcohol, ethyl alcohol, N-propyl alcohol, i-propyl alcohol, N-butyl alcohol, i-butyl alcohol, s-butyl alcohol and t-butyl alcohol. These can be used alone or in combination.

  Among these reaction solvents, in order to produce the acrylic polymer (A), it is preferable to use an organic solvent that does not easily cause chain transfer during the polymerization reaction, for example, esters and ketones. From the viewpoint of the solubility of the polymer (A) and the ease of the polymerization reaction, use of ethyl acetate, methyl ethyl ketone, acetone or the like is preferable.

  The amount of the reaction solvent used can be appropriately set in consideration of the viscosity of the solution or dispersion in which the resulting acrylic polymer (A) is dissolved or dispersed. Usually, however, the obtained acrylic polymer ( By setting the amount in the range of 30 to 300 parts by weight with respect to 100 parts by weight of the solid content of A), uniform stirring can be performed.

  Moreover, as a polymerization initiator used in preparation of said acrylic polymer (A), the polymerization initiators used by normal solution polymerization methods, such as an organic peroxide and an azo compound, can be used. .

Specific examples of such polymerization initiators include t-butyl hydroperoxide, cumene hydroxide, dicumyl peroxide, benzoyl peroxide, lauroyl peroxide, caproyl peroxide, di-i-propyl peroxide. Dicarbonate, di-2-ethylhexyl-peroxydicarbonate, t-butyl peroxybivalate, 2,2-bis (4,4-di-t-butylperoxycyclohexyl) propane, 2,2-bis (4 , 4-Di-t-amylperoxycyclohexyl) propane, 2,2-bis (4,4-di-t-octylpa-oxycyclohexyl) propane, 2,2-bis (4,4-di-α-cumylpa) -Oxycyclohexyl) propane, 2,2-bis (4,4-di-t-butylperoxycyclohexyl) Sill) butane and 2,2-bis (4,4-di -t- octylperoxycarbonyl cyclohexyl) organic peroxides, such as butane;
Listed are azo compounds such as 2,2′-azobis-i-butyronitrile, 2,2′-azobis-2,4-dimethylvaleronitrile and 2,2′-azobis-4-methoxy-2,4-dimethylvaleronitrile. be able to.

  Such a polymerization initiator is usually 0.01 to 2.0 parts by weight, preferably 0.1 to 1.0 parts by weight with respect to 100 parts by weight of the total monomer components used. use. Moreover, since the uniformity of the acrylic polymer (A) obtained when these polymerization initiators are added over a long time may be impaired, it is preferable to add them quickly. In this case, the polymerization initiator is preferably dissolved or dispersed in the reaction solvent used in the reaction system to be added to prepare an organic solvent solution of the polymerization initiator, and this organic solvent solution is added. Is preferred.

  In the present invention, the reaction temperature of the acrylic polymer (A) is usually set in the range of 30 to 100 ° C., preferably 60 to 90 ° C. Under such conditions, the reaction time is usually 3 to 15 hours, preferably It is set within a range of 5 to 10 hours.

In the present invention, it is not necessary to use a chain transfer agent when producing the acrylic polymer (A), but a chain transfer agent can also be used if necessary. Examples of chain transfer agents that can be used in the present invention include n-dodecyl mercaptan,
Mention may be made of 2-mercaptoethanol. Such a chain transfer agent is usually in the range of 0 to 1 part by weight, preferably 0.01 to 0.10 part by weight, based on the components to be reacted.

  For example, the acrylic polymer (A) prepared as described above can be used by precipitating the product by adding a poor solvent and separating it from the reaction solution, but without separating it from the reaction solvent. It is advantageous to use it as it is in the next step.

  The protective film for optical members of the present invention comprises the above acrylic polymer (A) and an acrylic polymer (B) having a specific quaternary ammonium group in the side chain. And in this invention, the component which comprises the acrylic polymer (B) used as (B) component is the above-mentioned acrylic polymer (A) except the component unit which forms the quaternary amimonium group of a side chain. And almost the same composition.

That is, the acrylic polymer (B) used in the present invention is a copolymer having a quaternary ammonium group in the side chain and a quaternary ammonium group having a weight average molecular weight of 500 to 3000. The polymer (B) contains a repeating unit having a quaternary ammonium group in the side chain in an amount of 7 to 30% by weight of the entire acrylic polymer (B), and all monomers constituting the acrylic polymer (B) Among them, at least one kind of alkyl acrylate that is the same as the alkyl alkyl acrylate used in the acrylic polymer (A) and one or more kinds of the same functional group-containing monomer as the functional group-containing monomer are 70 to 90. It is a polymer copolymerized in a proportion by weight.

  In the present invention, for the acrylic polymer (B) having a quaternary ammonium group in the side chain, the same monomer as that for producing the acrylic polymer (A) and a monomer for introducing a tertiary amine group are used as usual. It can be produced by polymerizing by a method, preferably a solution polymerization method, and then quaternizing the tertiary amine group in the side chain using a quaternizing agent.

  Thus, since the acrylic polymer (B) has component units derived from monomers having almost the same composition as the acrylic polymer (A), the acrylic polymer (B) is dissolved in the acrylic polymer (A). The property becomes very good. Furthermore, the weight average molecular weight of the acrylic polymer (B) having a quaternary ammonium group in the side chain is in the range of 500 to 3000, preferably in the range of 800 to 2000, whereby the quaternary ammonium group is added to the side chain. The acrylic polymer (B) it has does not move in the pressure-sensitive adhesive and exists stably in the pressure-sensitive adhesive layer.

  As a method for forming such an acrylic polymer (B), there are a method of copolymerizing a monomer having a quaternary ammonium group and a method of adding a quaternizing agent after copolymerizing a tertiary amine monomer. In the present invention, a method of adding a quaternizing agent after copolymerizing a tertiary amine monomer is preferable from the viewpoint of good copolymerization and easy production.

Examples of monomers that introduce a tertiary amino group into the side chain include 2- (dimethylamino) ethyl (meth) acrylate and dimethylaminopropane (meth) acrylamide. These can be used alone or in combination.

The copolymerization amount of such a tertiary amine group-containing monomer is usually in the range of 7 to 30% by weight, preferably 15 to 25% by weight.
The quaternizing agent used in the present invention is preferably a quaternizing agent having an alkyl group with a total carbon number of 2 or more. Examples of such a quaternizing agent include dimethyl sulfate, diethyl Examples thereof include dialkyl sulfuric acid such as sulfuric acid; alkylbenzyl chloride, benzyl chloride, ethyl chloride, propyl chloride, butyl chloride, ethyl bromide, butyl bromide, ethyl iodide, butyl iodide, and α-chloroparaxylene. These quaternizing agents are usually used alone, but can also be used in combination.

Such a quaternizing agent is usually added in an amount of 0. 1 mol per 1 mol of the tertiary amine group-containing monomer.
It is used in an amount in the range of 5 to 2.0 mol, preferably in an amount in the range of 0.7 to 1.0 mol.

As the organic solvent and polymerization initiator used here, those used in the production of the above-mentioned acrylic polymer (A) can be used, but the weight average molecular weight of the acrylic polymer (B) is 500 to 3000. Since the molecular weight is relatively low, preferably 800 to 2000, it is preferable to adjust the molecular weight by adding a chain transfer agent. In the present invention, a polymer having a desired molecular weight can be produced by using a chain transfer agent when producing the acrylic polymer (B). Examples of chain transfer agents that can be used in the present invention include n-dodecyl mercaptan and 2-mercaptoethanol. Such a chain transfer agent is usually used in an amount within the range of 1 to 40 parts by weight, preferably 20 to 30 parts by weight, based on the components to be reacted.
Other conditions are the same as the manufacturing conditions of the acrylic polymer (A).

  After forming a copolymer having a tertiary amine group in the side chain in this way, the tertiary amine group is quaternized. In addition, since the quaternization reaction is also performed in an organic solvent, it is preferable to transfer the obtained copolymer as it is to the next step without separation from the reaction solution.

In the quaternization reaction, a copolymer having a tertiary amine group in the side chain produced as described above is dissolved or dispersed in an organic solvent, and air in the reaction vessel is nitrogen gas to avoid coloring. After substituting with an inert gas such as, the temperature of the reaction solution is usually adjusted to a range of 30 to 80 ° C., and then a quaternizing agent is added. Depending on the amount of quaternizing agent to be added, the amount of quaternized ammonium groups to be generated differs, but the amount of quaternized ammonium groups generated is the total number of remaining tertiary amine groups (number) and generated quaternary ammonium groups (number). The ratio to the number of ammonium groups (number of quaternary ammonium groups / (number of tertiary amine groups + number of quaternary ammonium groups)) is usually in the range of 0.7 to 1.0, preferably 0.8 to 1.0. By reacting the quaternizing agent so as to be within the range of the above, it is possible to develop a very excellent antistatic property, and the remaining tertiary amine is added when the crosslinking agent (C) described later is added. In addition, since it has an effect of accelerating the reaction, it is not preferable to leave a large amount of tertiary amine groups, and it is desirable to adjust the amount of remaining tertiary amine as described above.

  For the acrylic polymer (B) having a quaternary ammonium group in the side chain thus obtained, the weight average molecular weight measured using gel permeation chromatography (GPC) is usually in the range of 500 to 3000. , Preferably in the range of 800-2000. The glass transition temperature (Tg) of the acrylic polymer (A) is usually in the range of -70 to + 30 ° C, preferably in the range of -70 to 0 ° C.

  The protective film for an optical member of the present invention comprises the acrylic polymer (A) and the acrylic polymer (B) as described above. The acrylic polymer (B) needs to be blended in an amount within the range of 2 to 10 parts by weight with respect to 100 parts by weight of the acrylic polymer (A), and further within the range of 2 to 8 parts by weight. It is preferable to mix | blend in the quantity in the inside. By blending the acrylic polymer (B) in such an amount, good antistatic properties can be expressed, and the protective film for optical members of the present invention can be prevented from being soiled. The protective film for optical members of the invention comes to have high transparency.

  The protective film for an optical member of the present invention can be produced by mixing the acrylic polymer (A) produced as described above and the acrylic polymer (B). The acrylic polymer (A) and the acrylic polymer (B) may be dissolved or dispersed in the reaction solvent when produced by a solution polymerization method. In the present invention, the polymer is separated from the reaction solvent. Without mixing with the solution. In this case, the type of solvent may be different. Furthermore, a crosslinking agent (C) can be added to improve the collection of the pressure-sensitive adhesive and prevent bleeding of the acrylic polymer (B).

  As a crosslinking agent used here, an isocyanate crosslinking agent, an epoxy crosslinking agent, and a metal chelate crosslinking agent can be mentioned. When these crosslinking agents are used, the amount of the crosslinking agent used is usually 0.5 to 10 parts by weight with respect to 100 parts by weight of the total amount of the acrylic polymer (A) and the acrylic polymer (B). Preferably it exists in the range of 1-7 weight part.

  The protective film for optical members of the present invention can be obtained by forming a pressure-sensitive adhesive layer on at least one surface of the aforementioned base film using the solution obtained as described above.

  The pressure-sensitive adhesive layer can be formed by applying the coating solution directly on the surface of the base film, but usually after applying the coating solution on the surface of the cover film that has been subjected to the release treatment and removing the solvent. The pressure-sensitive adhesive formed on the surface of the cover film can be transferred to the surface of the base film to form a pressure-sensitive adhesive layer. A uniform pressure-sensitive adhesive layer can be formed by transferring the pressure-sensitive adhesive layer to the surface of the base film after the pressure-sensitive adhesive is applied to the surface of the cover film that has been once peeled. In addition, after transferring the pressure-sensitive adhesive layer, the surface of the pressure-sensitive adhesive is protected by the cover film by not removing this cover film until just before use, and the surface of the pressure-sensitive adhesive of the protective film for optical members of the present invention Can be prevented from being contaminated.

  The thickness of the pressure-sensitive adhesive of the protective film for optical members thus formed is usually in the range of 5 to 50 μm, preferably 10 to 30 μm, and the thickness of the base film is usually 10 to 50 μm, Since it is preferably 20 to 40 μm, the total thickness of the protective film for optical members of the present invention is usually in the range of 15 to 100 μm, preferably 30 to 80 μm.

  The protective film for an optical member according to the present invention peels off and attaches the cover film to the surface of an optical display device such as a liquid crystal display device, a plasma display, or an SED display, thereby attaching the surface of the optical display device as described above. Can be protected. In addition to such display devices, these optical components are adhered to the surfaces of components constituting display devices such as polarizing plates, retardation plates, liquid crystal cell plates, and transparent electrode plates constituting such display devices. Can protect the surface.

  Next, the protective film for optical members of the present invention will be described in detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

[Production example]
[Production Example 1 Production of Acrylic Polymer (A)]
<Production of acrylic polymer (A-1)>
A 1-liter separable flask equipped with a thermometer, a stirrer, and a condenser was charged with 360 parts by weight of ethyl acetate (EtAc), and 383.2 parts by weight of 2-ethylhexyl acrylate (2EHA), 2-hydroxy 12.8 parts by weight of ethyl acrylate (2HEA) and 4 parts by weight of acrylic acid (AA) were added and stirred at 70 ° C.

Next, a solution prepared by dissolving 0.4 parts by weight of azobisisobutylnitrile (AIBN) as a reaction initiator in 4 parts by weight of ethyl acetate (EtAc) was quickly added, and the reaction was continued at 70 ° C. for 1 hour.
Thereafter, 1 hour and 2 hours after the start of the reaction, a solution prepared by dissolving 0.4 parts by weight of the initiator azobisisobutylnitrile (AIBN) in 4 parts by weight of ethyl acetate (EtAc) was quickly added.
The reaction was continued for a total of 6 hours.

After 6 hours, the temperature of the reaction solution was returned to room temperature to obtain a reaction solution of the resulting acrylic polymer. The nonvolatile content of the acrylic polymer in this reaction solution was 50%, and the weight average molecular weight was 700,000.
When the glass transition temperature of the acrylic polymer (A-1) was calculated according to the FOX formula, the glass transition temperature (Tg) of the acrylic polymer (A-1) was -68 ° C.

<Production of acrylic polymer (A-2)>
A 1-liter separable flask equipped with a thermometer, stirrer, dropping funnel and condenser and purged with nitrogen was charged with 500 parts by weight of ethyl acetate, to which 280 parts by weight of 2-ethylhexyl acrylate (2EHA), ethoxydi Elene glycol acrylate (EDA
) 103.2 parts by weight, 2-hydroxyethyl acrylate (2HEA) 12.8 parts by weight and acrylic acid (AA) 4 parts by weight were added and stirred at 70 ° C.

  Next, a solution prepared by dissolving 0.4 parts by weight of azobisisobutyronitrile (AIBN) as a reaction initiator in 4 parts by weight of ethyl acetate was quickly added dropwise from a separatory funnel, and the temperature was 70 ° C. for 6 hours. Stirring was continued.

  After 6 hours, the temperature of the reaction solution was returned to room temperature, a part of the reaction product was taken out, and the weight average molecular weight was measured by GPC. The weight average of the obtained acrylic polymer (A-2) The molecular weight (Mw) was 800,000.

  Moreover, when the glass transition temperature of this acrylic polymer (A-2) was computed according to the formula of FOX, the glass transition temperature (Tg) of this acrylic polymer (A-2) was -68 degreeC.

[Production Example 2 Production of Acrylic Polymer (B)]
<Production of acrylic polymer (B-1)>
A 11.8 liter separable flask equipped with a thermometer, stirrer, dropping funnel and condenser was charged with 121.8 parts by weight of methyl ethyl ketone (MEK), and 75.8 parts by weight of 2-ethylhexyl acrylate (2EHA) was added thereto. Further, 20 parts by weight of dimethylaminoethyl acrylate (DMAEA) and 30 parts by weight of n-dodesulmercaptan (NDM) as a chain transfer agent were added and stirred.

Next, a solution prepared by dissolving 0.1 part by weight of azobisisobutyronitrile (AIBN) as a reaction initiator in 1 part by weight of methyl ethyl ketone (MEK) was quickly added, and the reaction was continued at 70 ° C. for 1 hour.

Thereafter, a solution in which 0.1 part by weight of azobisisobutylnitrile (AIBN) as a reaction initiator was dissolved in 1 part by weight of methyl ethyl ketone (MEK) immediately after 30 minutes, one hour and one and a half hours after the start of the reaction. In addition, azobisisobutyronitrile (AIBN) 0 2 hours after addition of reaction initiator
. A solution obtained by dissolving 1 part by weight in 1 part by weight of methyl ethyl ketone (MEK), 3.2 parts by weight of 2-hydroxyethyl acrylate (2HEA) and 1 part by weight of acrylic acid (AA) were added, and the reaction was continued for a total of 6 hours. .

After 6 hours, the temperature of the reaction solution was returned to room temperature. The non-volatile content of the tertiary amine polymer in the obtained reaction solution was 50%, and the weight average molecular weight was 1300. When the glass transition temperature of this acrylic polymer was calculated according to the FOX formula, The glass transition temperature (Tg) was -54 ° C.

  A tertiary amine polymer produced as described above was placed in a 1-liter separable flask equipped with a thermometer, a stirrer, a dropping funnel and a condenser and purged with nitrogen, and stirred at 40 ° C.

Subsequently, 17.6 parts by weight of dimethyl sulfate and 17.6 parts by weight of 17.5 parts by weight of methyl ethyl ketone (MEK) were placed in the dropping funnel and dropped over 30 minutes.
After completion of the dropwise addition, the reaction was maintained for 5 and a half hours, and the reaction was continued for a total of 6 hours.

After 6 hours, the reaction solution was returned to room temperature, and the resulting acrylic polymer (B-1) having a quaternary ammonium group was obtained. The non-volatile content in the obtained reaction liquid was 50%.
When the weight average molecular weight of the acrylic polymer (B-1) containing a quaternary ammonium group was measured in the same manner as the acrylic polymer (A-1), the weight average of the obtained acrylic polymer (B-1) was measured. The molecular weight (Mw) was 1300.

<Manufacture of acrylic polymer (B-2)>
A 11.8 liter separable flask equipped with a thermometer, stirrer, dropping funnel and condenser was charged with 121.8 parts by weight of methyl ethyl ketone (MEK), and 75.8 parts by weight of 2-ethylhexyl acrylate (2EHA) was added thereto. Further, 20 parts by weight of dimethylaminoethyl acrylate (DMAEA) and 30 parts by weight of n-dodesulmercaptan (NDM) as a chain transfer agent were added and stirred.

Next, a solution prepared by dissolving 0.1 part by weight of azobisisobutyronitrile (AIBN) as a reaction initiator in 1 part by weight of methyl ethyl ketone (MEK) was quickly added, and the reaction was continued at 70 ° C. for 1 hour.

Thereafter, a solution in which 0.1 part by weight of azobisisobutylnitrile (AIBN) as a reaction initiator was dissolved in 1 part by weight of methyl ethyl ketone (MEK) immediately after 30 minutes, one hour and one and a half hours after the start of the reaction. In addition, azobisisobutyronitrile (AIBN) 0 2 hours after addition of reaction initiator
. A solution obtained by dissolving 1 part by weight in 1 part by weight of methyl ethyl ketone (MEK), 3.2 parts by weight of 2-hydroxyethyl acrylate (2HEA) and 1 part by weight of acrylic acid (AA) were added, and the reaction was continued for a total of 6 hours. .

After 6 hours, the temperature of the reaction solution was returned to room temperature. The non-volatile content of the tertiary amine polymer in the obtained reaction solution was 50%, and the weight average molecular weight was 1300.
Moreover, when the glass transition temperature of this acrylic polymer was calculated according to the formula of FOX, the glass transition temperature (Tg) of this acrylic polymer was -54 ° C.

  A tertiary amine polymer synthesized as described above was placed in a 1-liter separable flask equipped with a thermometer, stirrer, dropping funnel and condenser and purged with nitrogen, and stirred at 40 ° C.

Next, a solution obtained by dissolving 21.5 parts by weight of diethyl sulfate in 21.5 parts by weight of methyl ethyl ketone (MEK) was placed in the dropping funnel and added dropwise over 30 minutes.
After completion of the dropwise addition, the reaction solution was continued for 5 and a half hours, and the reaction was continued for a total of 6 hours.

After 6 hours, the temperature of the reaction solution was returned to room temperature. The non-volatile content in the obtained reaction liquid was 50%.
When the weight average molecular weight was measured in the same manner as in the acrylic polymer (A-1), the weight average molecular weight (Mw) of the resulting tertiary amine polymer was 1300, and the glass transition temperature (Tg) calculated in the same manner. Was -54 ° C.

After 6 hours, the reaction solution was returned to room temperature, and the resulting acrylic polymer (B-2) having a quaternary ammonium group was obtained. The non-volatile content in the obtained reaction liquid was 50%.
When the weight average molecular weight of the acrylic polymer (B-2) containing a quaternary ammonium group was measured in the same manner as the acrylic polymer (A-1), the weight average of the obtained acrylic polymer (B-2) was measured. The molecular weight (Mw) was 1400.

<Production of acrylic polymer (B-3)>
In the production of the acrylic polymer (B-1), 20 parts by weight of dimethylmethacrylamide (DM) is used instead of 20 parts by weight of dimethylaminoethyl acrylate (DMAEA), and dimethyl sulfate (DM ₂ SO ₄ ) is used. The same operation was performed except that the amount was changed from 17.6 parts by weight to 16.0 parts by weight and MEK from 17.5 parts by weight to 16.0 parts by weight.

  When the weight average molecular weight was measured in the same manner as in the acrylic polymer (A-1), the weight average molecular weight (Mw) of the resulting tertiary amine polymer was 1300, and the glass transition temperature (Tg) calculated in the same manner. Was -54 ° C.

After 6 hours, the reaction solution was returned to room temperature, and the resulting acrylic polymer (B-3) having a quaternary ammonium group was obtained. The non-volatile content in the obtained reaction liquid was 50%.
When the weight average molecular weight of the acrylic polymer (B-3) containing a quaternary ammonium group was measured in the same manner as the acrylic polymer (A-1), the weight average of the obtained acrylic polymer (B-3) was measured. The molecular weight (Mw) was 1300.

<Production of acrylic polymer (B-4)>
In the production of the acrylic polymer (B-1), 20 parts by weight of dimethylmethacrylamide (DM) is used instead of 20 parts by weight of dimethylaminoethyl acrylate (DMAEA), and dimethyl sulfate (DM ₂ SO ₄ ) is used. The same operation was performed except that 19.5 parts by weight of diethyl sulfate (DE ₂ SO ₄ ) and 19.5 parts by weight of MEK were used instead of 17.5 parts by weight.

  When the weight average molecular weight was measured in the same manner as the acrylic polymer (A-1), the weight average molecular weight (Mw) of the obtained acrylic polymer (B-4) was 1300, and the glass transition calculated in the same manner. The temperature (Tg) was -54 ° C.

After 6 hours, the reaction solution was returned to room temperature, and the resulting acrylic polymer (B-4) having a quaternary ammonium group was obtained. The non-volatile content in the obtained reaction liquid was 50%.
When the weight average molecular weight of the acrylic polymer (B-4) containing a quaternary ammonium group was measured in the same manner as the acrylic polymer (A-1), the weight average of the obtained acrylic polymer (B-1) was measured. The molecular weight (Mw) was 1400.

<Production of acrylic polymer (B-5)>
In the production of the acrylic polymer (B-1), dimethylaminopropyl acrylamide (DMAP) was used instead of 20 parts by weight of dimethylaminoethyl acrylate (DMAEA).
The same operation was performed except that 20 parts by weight of AA) was used.

  When the weight average molecular weight was measured in the same manner as in the acrylic polymer (A-1), the weight average molecular weight (Mw) of the resulting tertiary amine polymer was 1300, and the glass transition temperature (Tg) calculated in the same manner. Was -44 ° C.

After 6 hours, the reaction solution was returned to room temperature, and the resulting acrylic polymer (B-5) having a quaternary ammonium group was obtained. The non-volatile content in the obtained reaction liquid was 50%.
When the weight average molecular weight of the acrylic polymer (B-5) containing a quaternary ammonium group was measured in the same manner as the acrylic polymer (A-1), the weight average of the obtained acrylic polymer (B-5) was measured. The molecular weight (Mw) was 1300.

<Production of acrylic polymer (B-6)>
In the production of the acrylic polymer (B-1), the same operation was performed except that methyl paratoluenesulfonate (PTSM) was changed to 26.0 parts by weight instead of DM ₂ SO ₄ .

  When the weight average molecular weight was measured in the same manner as in the acrylic polymer (A-1), the weight average molecular weight (Mw) of the resulting tertiary amine polymer was 1300, and the glass transition temperature (Tg) calculated in the same manner. Was -54 ° C.

After 6 hours, the reaction solution was returned to room temperature, and the resulting acrylic polymer (B-6) having a quaternary ammonium group was obtained. The non-volatile content in the obtained reaction liquid was 50%.
When the weight average molecular weight of the acrylic polymer (B-6) containing a quaternary ammonium group was measured in the same manner as the acrylic polymer (A-1), the weight average of the obtained acrylic polymer (B-6) was measured. The molecular weight (Mw) was 1400.

<Production of acrylic polymer (B-7)>
In the production of the acrylic polymer (B-1), the same operation was performed except that 75.8 parts by weight of butyl acrylate (BA) was used instead of 2EHA.

  When the weight average molecular weight was measured in the same manner as in the acrylic polymer (A-1), the weight average molecular weight (Mw) of the obtained tertiary amine polymer was 1300, and the glass transition temperature (Tg) calculated in the same manner. Was -54 ° C.

After 6 hours, the reaction solution was returned to room temperature, and the resulting acrylic polymer (B-7) having a quaternary ammonium group was obtained. The non-volatile content in the obtained reaction liquid was 50%.
When the weight average molecular weight of the acrylic polymer (B-7) containing a quaternary ammonium group was measured in the same manner as the acrylic polymer (A-1), the weight average of the obtained acrylic polymer (B-7) was measured. The molecular weight (Mw) was 1300.

<Production of acrylic polymer (B-8)>
In the production of the acrylic polymer (B-1), the same operation was performed except that the reaction conditions were changed, that is, the reaction solvent was specifically changed to ethyl acetate (EtAc).

  When the weight average molecular weight was measured in the same manner as for the acrylic polymer (A-1), the weight average molecular weight (Mw) of the resulting tertiary amine polymer was 8000, and the glass transition temperature (Tg) calculated in the same manner. Was −34 ° C.

After 6 hours, the reaction solution was returned to room temperature, and the resulting acrylic polymer (B-8) having a quaternary ammonium group was obtained. The non-volatile content in the obtained reaction liquid was 50%.
When the weight average molecular weight of the acrylic polymer (B-8) containing a quaternary ammonium group was measured in the same manner as the acrylic polymer (A-1), the weight average of the obtained acrylic polymer (B-8) was measured. The molecular weight (Mw) was 8000.

<Production of acrylic polymer (B-9)>
In the production of the acrylic polymer (B-1), the same operation was performed except that 2HEA and AA copolymerized with 2EHA were not used.

  When the weight average molecular weight was measured in the same manner as in the acrylic polymer (A-1), the weight average molecular weight (Mw) of the obtained tertiary amine polymer was 1300, and the glass transition temperature (Tg) calculated in the same manner. Was −57 ° C.

After 6 hours, the reaction solution was returned to room temperature, and the resulting acrylic polymer (B-9) having a quaternary ammonium group was obtained. The non-volatile content in the obtained reaction liquid was 50%.
When the weight average molecular weight of the acrylic polymer (B-9) containing a quaternary ammonium group was measured in the same manner as the acrylic polymer (A-1), the weight average of the obtained acrylic polymer (B-9) was measured. The molecular weight (Mw) was 1300.

<Production of acrylic polymer B-10>
Same as the acrylic polymer (B-1) except that the amount of 2EHA used was changed to 90.8 parts by weight and the amount of DMAEA used was changed to 5 parts by weight in the production of the acrylic polymer (B-1). Thus, an acrylic polymer (B-10) was produced.

  When the weight average molecular weight was measured in the same manner as in the acrylic polymer (A-1), the weight average molecular weight (Mw) of the resulting tertiary amine polymer was 1300, and the glass transition temperature (Tg) calculated in the same manner. Was −52 ° C.

After 6 hours, the reaction solution was returned to room temperature, and the resulting acrylic polymer (B-8) having a quaternary ammonium group was obtained. The non-volatile content in the obtained reaction liquid was 50%.
When the weight average molecular weight of the acrylic polymer (B-10) containing a quaternary ammonium group was measured in the same manner as the acrylic polymer (A-1), the weight average of the obtained acrylic polymer (B-8) was measured. The molecular weight (Mw) was 1300.

<Production of acrylic polymer B-11>
In the production of the acrylic polymer (B-1), the same as the acrylic polymer (B-1) except that the amount of 2EHA used was changed to 55.8 parts by weight and the amount of DMAEA used was changed to 40 parts by weight. Thus, an acrylic polymer (B-11) was produced.

  When the weight average molecular weight was measured in the same manner as in the acrylic polymer (A-1), the weight average molecular weight (Mw) of the obtained tertiary amine polymer was 1300, and the glass transition temperature (Tg) calculated in the same manner. Was −39 ° C.

After 6 hours, the reaction solution was returned to room temperature, and the resulting acrylic polymer (B-11) having a quaternary ammonium group was obtained. The non-volatile content in the obtained reaction liquid was 50%.
When the weight average molecular weight of the acrylic polymer (B-11) containing a quaternary ammonium group was measured in the same manner as the acrylic polymer (A-1), the weight average of the obtained acrylic polymer (B-11) was measured. The molecular weight (Mw) was 1300.

[Example 1]
100 parts by weight of the acrylic polymer (A-1) obtained by the production of the acrylic polymer (A) of Production Example 1 above, and the acrylic polymer obtained by the production of the acrylic polymer (B) of Production Example 2 ( B-1) 4.0 parts by weight and, as a crosslinking agent (C), an isocyanate crosslinking agent L-45 (
A pressure-sensitive adhesive composition solution was produced by mixing 5 parts by weight of Soken Chemical Co., Ltd.

This pressure-sensitive adhesive composition solution was applied to a release film that had been subjected to a release treatment in advance so that the dry thickness was 20 μm, and the solvent was removed.
Next, this release film was attached to the surface of a base film made of polyethylene terephthalate (PET) having a thickness of 38 μm and left at 23 ° C. for 7 days.

The release film is removed from the three-layered film thus obtained (the film having the release film attached to the surface of the adhesive film of the protective film for optical members) and attached to a glass substrate to give a release voltage and contamination. And transparency were measured.
The results are shown in Table 1.

[Example 2]
In Example 1, instead of 4.0 parts by weight of the acrylic polymer (B-1) obtained in the production of the acrylic polymer (B) in Production Example 2, production of the acrylic polymer (B) in Production Example 2 A protective film for an optical member was produced in the same manner except that 4.0 parts by weight of the acrylic polymer (B-2) obtained in the above was used, and its peeling voltage, contamination, and transparency were measured.
The results are shown in Table 1.

Example 3
In Example 1, instead of 4.0 parts by weight of the acrylic polymer (B-1) obtained in the production of the acrylic polymer (B) in Production Example 2, production of the acrylic polymer (B) in Production Example 2 A protective film for an optical member was produced in the same manner except that 4.0 parts by weight of the acrylic polymer (B-3) obtained in the above was used, and its peeling voltage, contamination, and transparency were measured.
The results are shown in Table 1.

Example 4
In Example 1, instead of 4.0 parts by weight of the acrylic polymer (B-1) obtained in the production of the acrylic polymer (B) in Production Example 2, production of the acrylic polymer (B) in Production Example 2 A protective film for an optical member was produced in the same manner except that 4.0 parts by weight of the acrylic polymer (B-4) obtained in the above was used, and its peeling voltage, contamination, and transparency were measured.
The results are shown in Table 1.

Example 5
In Example 1, instead of 100 parts by weight of the acrylic polymer (A-1) obtained in the production of the acrylic polymer (A) in Production Example 1, it was obtained in the production of the acrylic polymer (A) in Production Example 1. A protective film for an optical member was produced in the same manner except that 100 parts by weight of the resulting acrylic polymer (A-2) was used, and its peeling voltage, contamination, and transparency were measured.
The results are shown in Table 1.

Example 6
In Example 2, instead of 100 parts by weight of the acrylic polymer (A-1) obtained by the production of the acrylic polymer (A) of Production Example 1, it was obtained by the production of the acrylic polymer (A) of Production Example 1. A protective film for an optical member was produced in the same manner except that 100 parts by weight of the resulting acrylic polymer (A-2) was used, and its peeling voltage, contamination, and transparency were measured.
The results are shown in Table 1.

Example 7
In Example 3, instead of 100 parts by weight of the acrylic polymer (A-1) obtained by the production of the acrylic polymer (A) of Production Example 1, it was obtained by the production of the acrylic polymer (A) of Production Example 1. A protective film for an optical member was produced in the same manner except that 100 parts by weight of the resulting acrylic polymer (A-2) was used, and its peeling voltage, contamination, and transparency were measured.
The results are shown in Table 1.

Example 8
In Example 4, instead of 100 parts by weight of the acrylic polymer (A-1) obtained by the production of the acrylic polymer (A) of Production Example 1, it was obtained by the production of the acrylic polymer (A) of Production Example 1. A protective film for an optical member was produced in the same manner except that 100 parts by weight of the resulting acrylic polymer (A-2) was used, and its peeling voltage, contamination, and transparency were measured.
The results are shown in Table 1.

[Comparative Example 1]
In Example 1, instead of 4.0 parts by weight of the acrylic polymer (B-1) obtained in the production of the acrylic polymer (B) in Production Example 2, production of the acrylic polymer (B) in Production Example 2 A protective film for an optical member was produced in the same manner except that 4.0 parts by weight of the acrylic polymer (B-5) obtained in the above was used, and its release voltage, contamination, and transparency were measured.
The results are shown in Table 1.

[Comparative Example 2]
In Example 1, instead of 4.0 parts by weight of the acrylic polymer (B-1) obtained in the production of the acrylic polymer (B) in Production Example 2, production of the acrylic polymer (B) in Production Example 2 A protective film for an optical member was produced in the same manner except that 4.0 parts by weight of the acrylic polymer (B-6) obtained in the above was used, and its peeling voltage, contamination, and transparency were measured.
The results are shown in Table 1.

[Comparative Example 3]
In Example 1, instead of 4.0 parts by weight of the acrylic polymer (B-1) obtained in the production of the acrylic polymer (B) in Production Example 2, production of the acrylic polymer (B) in Production Example 2 A protective film for an optical member was produced in the same manner except that 4.0 parts by weight of the acrylic polymer (B-7) obtained in the above was used, and its release voltage, contamination, and transparency were measured.
The results are shown in Table 1.

[Comparative Example 4]
In Example 1, instead of 4.0 parts by weight of the acrylic polymer (B-1) obtained in the production of the acrylic polymer (B) in Production Example 2, production of the acrylic polymer (B) in Production Example 2 A protective film for an optical member was produced in the same manner except that 4.0 parts by weight of the acrylic polymer (B-8) obtained in the above was used, and its peeling voltage, contamination, and transparency were measured.
The results are shown in Table 1.

[Comparative Example 5]
In Example 1, instead of 4.0 parts by weight of the acrylic polymer (B-1) obtained in the production of the acrylic polymer (B) in Production Example 2, production of the acrylic polymer (B) in Production Example 2 A protective film for an optical member was produced in the same manner except that 4.0 parts by weight of the acrylic polymer (B-9) obtained in the above was used, and its peeling voltage, contamination, and transparency were measured.
The results are shown in Table 1.

[Comparative Example 6]
In Example 1, a protective film for an optical member was produced in the same manner except that the amount of the acrylic polymer (B-1) used in Production Example 2 was changed to 1 part by weight, and the stripping voltage, contamination, and transparency were produced. Was measured.
The results are shown in Table 1.

[Comparative Example 7]
In Example 1, a protective film for an optical member was produced in the same manner except that the amount of the acrylic polymer (B-1) used in Production Example 2 was changed to 15 parts by weight, and the stripping voltage, contamination, and transparency were produced. Was measured.
The results are shown in Table 1.

註）表１において、
「2EHA」は、2-エチルヘキシルアクリレート、
「EDA」は、エトキシジエチレングリコールアクリレート、
「2HEA」は、2-ヒドロキシエチルアクリレート、
「AA」は、アクリル酸、
「DMAEA」は、ジメチルアミノエチルアクリレート
「ＤＭ」は、ジメチルアミノエチルメタクリレート、
「DMAPAA」は、ジメチルアミノプロピルアクリルアミド
「DM₂SO₄」は、硫酸ジメチル、
「DE₂SO₄」は、硫酸ジエチル、
「PTSM」は、パラトルエンスルホン酸メチル、
「Ｌ−４５」は、イソシアネート系架橋剤（綜研化学（株）製：Ｌ-４５）
「ＮＤＭ」は、ｎ−ドデシルメルカプタンを表す。

I) In Table 1,
"2EHA" is 2-ethylhexyl acrylate,
"EDA" is ethoxydiethylene glycol acrylate,
"2HEA" is 2-hydroxyethyl acrylate,
"AA" is acrylic acid,
“DMAEA” is dimethylaminoethyl acrylate “DM” is dimethylaminoethyl methacrylate,
`` DMAPAA '' is dimethylaminopropyl acrylamide `` DM ₂ SO ₄ '' is dimethyl sulfate,
“DE ₂ SO ₄ ” is diethyl sulfate,
“PTSM” is methyl paratoluenesulfonate,
“L-45” is an isocyanate crosslinking agent (manufactured by Soken Chemical Co., Ltd .: L-45).
“NDM” represents n-dodecyl mercaptan.

  In addition, [number of quaternary ammonium groups / (number of tertiary amines + number of quaternary ammonium groups)] in the pressure-sensitive adhesive layer of the protective film for optical members shown in Table 1 was all 1.

As described above, in the protective film for optical members of the present invention, the component unit for imparting antistatic properties blended in the adhesive and the component unit of the adhesive constituting the adhesive are the same. Therefore, the components blended for imparting antistatic properties are well dispersed with respect to the main components of the pressure-sensitive adhesive. Therefore, the static electricity accumulated in the electronic component can be efficiently discharged by sticking the protective film for optical members of the present invention. Furthermore, in the protective film for optical members of the present invention, the component for imparting antistatic properties and the pressure-sensitive adhesive are uniform, and the component for imparting antistatic properties does not ooze out on the pressure-sensitive adhesive surface. Protect film is not easily contaminated. Moreover, since the compatibility of the component to be blended to impart antistatic properties and the main component of the adhesive is good, the transparency of the protective film for optical members of the present invention is
High transparency is exhibited without being damaged by the components blended for imparting charging properties.

Claims (10)

Acrylic polymer (A) formed by copolymerization of (meth) acrylic acid alkyl ester and a functional group-containing monomer copolymerizable therewith: 100 parts by weight of a quaternary ammonium group in the side chain Acrylic polymer (B) having an average molecular weight of 500 to 3000: a pressure-sensitive adhesive layer composed of 2 to 10 parts by weight is laminated on a base film,
The acrylic polymer (B) is
The acrylic polymer contains 7 to 30% by weight of the repeating unit having a quaternary ammonium group in the side chain of the entire acrylic polymer (B) and is included in all monomers constituting the acrylic polymer (B). 70-90% by weight in total of one or more kinds of alkyl acrylates identical to the alkyl acrylate copolymerized in (A) and one or more kinds of functional group-containing monomers identical to the functional group-containing monomers A protective film for optical members, which is a copolymer copolymerized at a ratio. The acrylic polymer (B) is characterized in that an acrylic polymer having a tertiary amine in the side chain is quaternized using a quaternizing agent having a total number of alkyl groups of 2 or more. The protective film for an optical member according to claim 1.   The protective film for an optical member according to claim 2, wherein the quaternizing agent is dimethyl sulfate and / or diethyl sulfate. Monomers that form an acrylic polymer having a tertiary amine in the side chain are 2- (dimethylamino) ethyl (meth) acrylate, dimethylaminopropyl (meth) acrylamide, N, N, -dimethylaminoethyl acrylate, and 3. The protected film for an optical member according to claim 2, wherein the protected film is at least one monomer selected from the group consisting of N, N-dimethylaminoethyl methacrylate.   The base film of the protective film for an optical member is at least one film selected from the group consisting of an acrylic film, a polyester film, a polyethylene terephthalate film, and a polycarbonate film. The protective film for an optical member according to item 1.   The thickness of the said adhesive layer exists in the range of 5-50 micrometers, The protective film for optical members of Claim 1 characterized by the above-mentioned. The acrylic polymer (B) comprises (b-1) an acrylic monomer having the same composition as the acrylic polymer (A): 70 to 90% by weight, and (b-2) a monomer having a tertiary amine group. 2. The protective film for an optical member according to claim 1, wherein the protective film can be obtained by performing a quaternization reaction using a quaternizing agent after polymerization.   The (meth) acrylic acid alkyl ester has an alkyl group having 2 to 8 carbon atoms, and the functional group-containing monomer of at least one of a hydroxyl group-containing monomer and a carboxyl group-containing monomer is combined with the alkyl acrylate ester. 2. The protective film for an optical member according to claim 1, wherein the protective film is polymerized.   The ratio of the tertiary amine group to the quaternary ammonium group in the acrylic polymer (B) [number of quaternary ammonium groups / (number of tertiary amine groups + number of quaternary ammonium groups)] is 0.7 to 1.0. The protective film for an optical member according to claim 2, wherein the protective film is within the range. The glass transition temperature (Tg) of the acrylic polymer (A) is in the range of −70 to less than 30 ° C., and the glass transition temperature (Tg) of the acrylic polymer (B) is in the range of −70 to 30 ° C. The protective film for optical members according to claim 1, wherein the protective film is for optical members.