JP2018109093A - Surface protective film - Google Patents

Abstract

An optical surface with a separator that can suppress the occurrence of dents caused by the separator by a separator that suppresses the peeling force to the adhesive layer of the separator, has excellent peelability and workability, and has excellent cushioning properties. Provision of protective film. An optical surface protection film having an adhesive layer on at least one surface of a base film, and an optical surface protection with a separator having a separator on the surface opposite to the surface in contact with the adhesive layer of the base film. The separator has a release layer and a polyester base, the polyester base has a cavity, and the polyester base has a thickness of 25 to 100 μm. An optical surface protective film with a separator having a 180 ° -triggering peel strength with respect to the pressure-sensitive adhesive layer of 0.7 N / 50 mm or less. An optical surface protective film with a separator, wherein the pressure-sensitive adhesive layer preferably contains a (meth) acrylic polymer. [Selection figure] None

Description

  The present invention relates to an optical surface protective film with a separator. In particular, an adhesive constituting an optical surface protective film used for protecting the surface of an optical member (for example, a polarizing plate, a wave plate, a retardation plate, an optical compensation film, a reflection sheet, a brightness enhancement film, etc. used in a liquid crystal display). By sticking (stacking) a specific separator used to protect the surface of the agent layer until actual use, it is excellent in peelability and workability, and can prevent the occurrence of dents, which is useful.

  The surface protective film generally has a configuration in which an adhesive layer is provided on a film-like base film (support). Such a surface protective film is bonded to an optical member as an adherend through the pressure-sensitive adhesive layer, and is used for the purpose of protecting the optical member from scratches and dirt on the surface during processing, transportation, inspection, and the like. It is done. For example, a panel of a liquid crystal display is formed by bonding an optical member such as a polarizing plate or a wave plate to a liquid crystal cell via an adhesive layer. Such a pressure-sensitive adhesive layer is protected and stored by a release-treated separator or the like from the necessity of protection from drying or the like before being actually attached to an optical member (Patent Document 1).

  Thereafter, when the surface of the pressure-sensitive adhesive layer of the surface protective film is actually attached to the optical member and used, the separator is peeled off and removed.

JP2012-224811

  In addition, when a separator is thick, when it peels and removes, when the peeling force (adhesive force) with respect to the adhesive layer which comprises the surface protection film of a separator becomes high, the problem inferior to peelability and workability | operativity will generate | occur | produce.

  In addition, when a thin separator is used instead of a thick separator when applying adhesive, it is caused by fine particles (for example, polyester filler) contained in the base material constituting the separator attached to the separator surface. Thus, when the pressure-sensitive adhesive layer is formed, it becomes a cause of generating dents on the surface of the pressure-sensitive adhesive layer. Furthermore, if the surface of the pressure-sensitive adhesive layer is bonded to the adherend with the dent formed, bubbles will enter the dent portion (space) between the pressure-sensitive adhesive layer and the adherend, and during inspection of the adherend There arises a problem that deteriorates the inspectability.

  In view of the above circumstances, the present inventors have intensively studied and, as a result, specified the thickness of the polyester base material constituting the separator to be laminated on the optical surface protective film, and further provided a cavity, whereby the stiffness of the separator is improved. By reducing (rigidity), it is possible to suppress the peeling force of the separator to the pressure-sensitive adhesive layer, and it is excellent in peelability and workability. An object of the present invention is to provide an optical surface protective film with a separator that can suppress generation and has excellent inspection properties.

  That is, the optical surface protective film with a separator of the present invention has an optical surface protective film having an adhesive layer on at least one side of the substrate film, and a surface opposite to the surface in contact with the adhesive layer of the substrate film. And a separator-containing optical surface protective film having a separator, wherein the separator has a release layer and a polyester-based substrate, the polyester-based substrate has a cavity, and the thickness of the polyester-based substrate However, it is 25-100 micrometers, and the 180 degree | times trigger peeling force with respect to the said adhesive layer of the said separator is 0.7 N / 50mm or less, It is characterized by the above-mentioned.

  The optical surface protective film with a separator of the present invention preferably has a porosity of 15% or more with respect to the volume of the polyester-based substrate.

  In the optical surface protective film with a separator of the present invention, the base film is preferably a polyester film.

  In the optical surface protective film with a separator of the present invention, the pressure-sensitive adhesive layer is preferably formed from a pressure-sensitive adhesive composition containing a (meth) acrylic polymer.

  This invention specifies the thickness of the polyester-type base material which comprises the separator laminated | stacked on the surface protection film for optics, and also provides the peeling force with respect to the adhesive layer which comprises the surface protection film for optics of a separator by providing a cavity. Suppressing, excellent peelability and workability, and further having a cavity, it is possible to suppress the occurrence of dents caused by the separator by the separator having excellent cushioning properties. An optical surface protective film with a separator excellent in inspectability in a bonded state can be obtained and useful.

It is a typical sectional view showing an example of 1 composition of an optical surface protection film with a separator concerning the present invention. It is typical sectional drawing which shows one structural example at the time of peeling a separator from the optical surface protection film with a separator concerning this invention.

  Hereinafter, embodiments of the present invention will be described in detail.

<Overall structure of optical surface protective film with separator>
An optical surface protective film with a separator disclosed herein (hereinafter sometimes simply referred to as “surface protective film”) is generally a pressure-sensitive adhesive layer surface in a form called an adhesive tape, an adhesive label, an adhesive film, or the like. Is protected by a separator, and in particular, surface protection that protects the surface of optical components during processing, inspection, and transportation of optical components (for example, optical components used as liquid crystal display panel components such as polarizing plates and wave plates). Suitable as a film. The pressure-sensitive adhesive layer in the surface protective film is typically formed continuously, but is not limited to such a form, and is formed in a regular or random pattern such as a spot or stripe. It may be an adhesive layer. In addition, the surface protective film disclosed herein may be in the form of a roll or a single sheet.

<Base film>
The optical surface protective film which comprises the optical surface protective film with a separator of this invention has a base film, It is characterized by the above-mentioned. In the technology disclosed herein, the resin material constituting the base film can be used without any particular limitation. For example, transparency, mechanical strength, thermal stability, moisture shielding property, isotropic property, It is preferable to use a material excellent in properties such as flexibility and dimensional stability. In particular, since the base film has flexibility, the pressure-sensitive adhesive composition can be applied by a roll coater or the like, and can be wound up into a roll shape, which is useful.

  Examples of the base film (support) include polyester polymers such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polybutylene terephthalate; cellulose polymers such as diacetyl cellulose and triacetyl cellulose; polycarbonate polymers; An acrylic polymer such as polymethyl methacrylate; and the like, a plastic film composed of a resin material having a main resin component (a main component of the resin component, typically a component occupying 50% by weight or more), It can be preferably used as a film. Other examples of the resin material include styrene polymers such as polystyrene and acrylonitrile-styrene copolymers; olefin polymers such as polyethylene, polypropylene, polyolefins having a cyclic or norbornene structure, and ethylene-propylene copolymers; Examples of the resin material include vinyl chloride polymers; amide polymers such as nylon 6, nylon 6,6, and aromatic polyamide. Still other examples of the resin material include imide polymers, sulfone polymers, polyether sulfone polymers, polyether ether ketone polymers, polyphenylene sulfide polymers, vinyl alcohol polymers, vinylidene chloride polymers, vinyl butyral polymers. , Arylate polymers, polyoxymethylene polymers, epoxy polymers and the like. A base film made of a blend of two or more of the above-described polymers may be used.

  As the base film, a plastic film made of a transparent thermoplastic resin material can be preferably used. Among the plastic films, it is more preferable to use a polyester film. Here, the polyester film includes a polyester polymer material (polyester resin) having a main skeleton based on an ester bond such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate, or the like as a main resin component. Say things. Such a polyester film has preferable characteristics as a base film for a surface protective film, such as excellent optical characteristics and dimensional stability.

  Various additives such as an antioxidant, an ultraviolet absorber, a plasticizer, and a colorant (pigment, dye, etc.) may be blended in the resin material constituting the base film, if necessary. For example, a known or conventional surface treatment such as corona discharge treatment, plasma treatment, ultraviolet irradiation treatment, acid treatment, alkali treatment, and application of a primer may be performed. Such surface treatment can be, for example, a treatment for improving the adhesion between the base film and the pressure-sensitive adhesive layer (the anchoring property of the pressure-sensitive adhesive layer).

  As the base film, it is also possible to use a plastic film that has been subjected to antistatic treatment. Use of the base film is preferable because charging of the surface protective film itself when peeled can be suppressed. In addition, the base film is a plastic film, and an antistatic treatment is performed on the plastic film, so that the surface protection film itself can be reduced in charge and can have an excellent antistatic ability on the adherend. In addition, there is no restriction | limiting in particular as a method to provide an antistatic function, A conventionally well-known method can be used, for example, antistatic resin which consists of an antistatic agent and a resin component, a conductive polymer, a conductive substance Examples thereof include a method of applying a conductive resin, a method of depositing or plating a conductive material, a method of kneading an antistatic agent, and the like.

  As thickness of the said base film, it is 5-200 micrometers normally, Preferably it is about 10-100 micrometers. When the thickness of the base film is within the above range, it is preferable because it is excellent in bonding workability to the adherend, peelability from the adherend and workability.

  The surface protective film disclosed herein can be implemented in an embodiment including other layers in addition to the base film, the pressure-sensitive adhesive layer, and the separator. Examples of the other layer include an undercoat layer (anchor layer) that improves the anchoring property of the antistatic layer and the pressure-sensitive adhesive layer.

<Adhesive layer>
The pressure-sensitive adhesive layer used in the present invention can be used without particular limitation as long as it is formed from a pressure-sensitive adhesive composition containing a pressure-sensitive adhesive polymer. Examples of the pressure-sensitive adhesive composition include acrylic pressure-sensitive adhesives, urethane-based pressure-sensitive adhesives, synthetic rubber-based pressure-sensitive adhesives, natural rubber-based pressure-sensitive adhesives, silicone-based pressure-sensitive adhesives, and polyester-based pressure-sensitive adhesives. It is preferable to use (contain) at least one selected from the group consisting of an acrylic pressure-sensitive adhesive, a urethane-based pressure-sensitive adhesive, and a silicone-based pressure-sensitive adhesive, and the (meth) acrylic polymer that is the pressure-sensitive adhesive polymer The use of the contained pressure-sensitive adhesive composition (acrylic pressure-sensitive adhesive) is a particularly preferred embodiment.

  When the pressure-sensitive adhesive layer uses an acrylic pressure-sensitive adhesive, a (meth) acrylic polymer that is a pressure-sensitive polymer constituting the acrylic pressure-sensitive adhesive is an alkyl having 1 to 14 carbon atoms as a raw material monomer constituting the same. A (meth) acrylic monomer having a group can be used as the main monomer. As said (meth) acrylic-type monomer, 1 type (s) or 2 or more types can be used. By using the (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms, it becomes easy to control the peeling force (adhesive strength) to the adherend (protected body) to be low and light peeling. A surface protective film excellent in removability and removability can be obtained. In the present invention, the (meth) acrylic polymer refers to an acrylic polymer and / or a methacrylic polymer, and the (meth) acrylate refers to acrylate and / or methacrylate.

  Specific examples of the (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms include, for example, 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-dodecyl (meth) acrylate, n-tridecyl (meth) acrylate, n-tetradecyl (meth) acrylate, etc. It is done.

  Among these, in the surface protective film of the present invention, in particular, n-butyl (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-dodecyl (meth) acrylate, n-tridecyl (meth) acrylate, n-tetradecyl (meth) ) A (meth) acrylic monomer having an alkyl group having 4 to 14 carbon atoms such as acrylate is preferred. In particular, by using a (meth) acrylic monomer having an alkyl group having 4 to 14 carbon atoms, it becomes easy to control the peel force (adhesive force) to the adherend to be low and has excellent removability. It becomes.

  In particular, it is preferable to contain 65% by weight or more of a (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms with respect to 100% by weight of the total amount of monomer components constituting the (meth) acrylic polymer. More preferably, it is 75% by weight or more, more preferably 85 to 99.9% by weight, and most preferably 90 to 99% by weight. If it is less than 50% by weight, the appropriate wettability of the pressure-sensitive adhesive composition and the cohesive strength of the pressure-sensitive adhesive layer are inferior, which is not preferable.

  In the (meth) acrylic polymer, a hydroxyl group-containing (meth) acrylic monomer can be used as a raw material monomer. As said hydroxyl group containing (meth) acrylic-type monomer, 1 type (s) or 2 or more types can be used. By using the hydroxyl group-containing (meth) acrylic monomer, it becomes easy to control the crosslinking of the pressure-sensitive adhesive composition, and as a result, balance between improvement of wettability by flow and reduction of peeling force (adhesive strength) in peeling. It becomes easier to control.

  Examples of the hydroxyl group-containing (meth) acrylic monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 6-hydroxyhexyl (meth) acrylate. , 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, (4-hydroxymethylcyclohexyl) methyl acrylate, N-methylol (meth) acrylamide, and the like. .

  The hydroxyl group-containing (meth) acrylic monomer is preferably contained in an amount of 25% by weight or less, more preferably 15% by weight or less, based on 100% by weight of the total amount of monomer components constituting the (meth) acrylic polymer. More preferably, it is 0.1 to 10% by weight. Within the above range, the balance between the wettability of the pressure-sensitive adhesive composition and the cohesive force of the resulting pressure-sensitive adhesive layer can be easily controlled, which is preferable.

  In addition, as another polymerizable monomer component, the Tg is 0 ° C. or lower (usually −100 ° C. or higher) for the reason that it is easy to balance the adhesive performance, and the glass transition temperature or peeling of the (meth) acrylic polymer. A polymerizable monomer or the like for adjusting the property can be used as long as the effects of the present invention are not impaired.

  In the (meth) acrylic polymer, a carboxyl group-containing (meth) acrylic monomer can be used as a raw material monomer. By using the carboxyl group-containing (meth) acrylic monomer, the pressure-sensitive adhesive layer (surface protective film) can be prevented from increasing in adhesive strength over time, re-peelability, adhesive strength-increasing property, and work Excellent in properties. In addition to the cohesive force of the pressure-sensitive adhesive layer, it is excellent in shearing force and is preferable.

  Examples of the carboxyl group-containing (meth) acrylic monomer include (meth) acrylic acid, carboxylethyl (meth) acrylate, carboxylpentyl (meth) acrylate, and the like.

  The carboxyl group-containing (meth) acrylic monomer is preferably 10% by weight or less, preferably 0 to 8% by weight with respect to 100% by weight of the total amount of monomer components constituting the (meth) acrylic polymer. Is more preferable, and it is still more preferable that it is 0 to 6 weight%. Within the above range, the balance between the wettability of the pressure-sensitive adhesive composition and the cohesive force of the resulting pressure-sensitive adhesive layer can be easily controlled, which is preferable.

  Furthermore, the said (meth) acrylic-type polymer can use other polymerizable monomers other than the said raw material monomer, unless it is in the range which does not impair the characteristic of this invention. For example, as the other polymerizable monomer, a cohesive force / heat resistance improving component such as a cyano group-containing monomer, vinyl ester monomer, aromatic vinyl monomer, amide group-containing monomer, imide group-containing monomer, amino group-containing monomer, epoxy A component having a functional group that functions as an improvement in peeling force (adhesive force) and a crosslinking base point such as a group-containing monomer, N-acryloylmorpholine, and vinyl ether monomer can be used as appropriate. Among these, it is preferable to use nitrogen-containing monomers such as cyano group-containing monomers, amide group-containing monomers, imide group-containing monomers, amino group-containing monomers, and N-acryloylmorpholine. Use of a nitrogen-containing monomer is useful because it can ensure an appropriate peeling force (adhesive strength) that does not cause floating or peeling, and can provide a surface protective film having excellent shearing force. These polymerizable monomers can be used alone or in combination of two or more.

  Examples of the cyano group-containing monomer include acrylonitrile and methacrylonitrile.

  Examples of the amide group-containing monomer include acrylamide, methacrylamide, diethylacrylamide, N-vinylpyrrolidone, N, N-dimethylacrylamide, N, N-dimethylmethacrylamide, N, N-diethylacrylamide, N, N-diethyl. Examples include methacrylamide, N, N′-methylenebisacrylamide, N, N-dimethylaminopropyl acrylamide, N, N-dimethylaminopropyl methacrylamide, diacetone acrylamide, and the like.

  Examples of the imide group-containing monomer include cyclohexylmaleimide, isopropylmaleimide, N-cyclohexylmaleimide, and itaconimide.

  Examples of the amino group-containing monomer include aminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, and the like.

  Examples of the vinyl ester monomer include vinyl acetate, vinyl propionate, vinyl laurate, and the like.

  Examples of the aromatic vinyl monomer include styrene, chlorostyrene, chloromethyl styrene, α-methyl styrene, and other substituted styrene.

  Examples of the epoxy group-containing monomer include glycidyl (meth) acrylate, methyl glycidyl (meth) acrylate, and allyl glycidyl ether.

  Examples of the vinyl ether monomer include methyl vinyl ether, ethyl vinyl ether, isobutyl vinyl ether, and the like.

  In the present invention, the other polymerizable monomer is preferably 0 to 30% by weight, and 0 to 10% by weight with respect to 100% by weight of the total amount of monomer components constituting the (meth) acrylic polymer. It is more preferable. The other polymerizable monomers can be appropriately adjusted in order to obtain desired characteristics.

  The (meth) acrylic polymer may further contain an alkylene oxide group-containing reactive monomer as a monomer component.

  Moreover, as an average addition mole number of the oxyalkylene unit of the said alkylene oxide group containing reactive monomer, it is preferable that it is 1-40 from a compatible viewpoint with an oxyalkylene group containing compound, and it is 3-40. Is more preferable, it is more preferable that it is 4-35, and it is especially preferable that it is 5-30. When the average added mole number is 1 or more, the effect of reducing the contamination of the adherend (protected body) tends to be obtained efficiently. Moreover, when the said average added mole number is larger than 40, since interaction with an oxyalkylene group containing compound is large and there exists a tendency for the viscosity of an adhesive composition to rise and for coating to become difficult, it is unpreferable. Note that the terminal of the oxyalkylene chain may be a hydroxyl group or may be substituted with another functional group.

  The alkylene oxide group-containing reactive monomer may be used alone or in combination of two or more, but the total content is the total amount of monomer components of the (meth) acrylic polymer. Among these, 0 to 20% by weight is preferable, and 0 to 10% by weight is more preferable. When the content of the alkylene oxide group-containing reactive monomer exceeds 20% by weight, the contamination on the adherend deteriorates, which is not preferable.

  Examples of the oxyalkylene unit of the alkylene oxide group-containing reactive monomer include those having an alkylene group having 1 to 6 carbon atoms, such as an oxymethylene group, an oxyethylene group, an oxypropylene group, and an oxybutylene group. It is done. The hydrocarbon group of the oxyalkylene chain may be linear or branched.

  The alkylene oxide group-containing reactive monomer is more preferably a reactive monomer having an ethylene oxide group. By using a reactive monomer-containing (meth) acrylic polymer having an ethylene oxide group as a base polymer, the compatibility between the base polymer and the oxyalkylene group-containing compound is improved, and bleeding to the adherend is suitably suppressed, A low-contamination pressure-sensitive adhesive composition is obtained.

  Examples of the alkylene oxide group-containing reactive monomer include (meth) acrylic acid alkylene oxide adducts and reactive surfactants having reactive substituents such as acryloyl group, methacryloyl group, and allyl group in the molecule. can give.

  Specific examples of the (meth) acrylic acid alkylene oxide adduct include, 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, methoxy polyethylene glycol (meth) acrylate, ethoxy polyethylene glycol (meth) acrylate, butoxy polyethylene glycol (meth) acrylate, octoxy polyethylene glycol (meth) acrylate, lauroxy polyethylene Glycol (meth) acrylate, stearoxy polyethylene glycol Le (meth) acrylate, phenoxy polyethylene glycol (meth) acrylate, methoxy polypropylene glycol (meth) acrylate, octoxypolyethylene glycol - polypropylene glycol (meth) acrylate.

  Specific examples of the reactive surfactant include, for example, an anionic reactive surfactant having a (meth) acryloyl group or an allyl group, a nonionic reactive surfactant, and a cationic reactive surfactant. Is given.

  The (meth) acrylic polymer preferably has a weight average molecular weight (Mw) of 100,000 to 5,000,000, more preferably 200,000 to 4,000,000, still more preferably 300,000 to 3,000,000, and most preferably 300,000 to 1,200,000. It is. When the weight average molecular weight is smaller than 100,000, the adhesive force tends to be generated due to the reduced cohesive force of the pressure-sensitive adhesive layer. On the other hand, when the weight average molecular weight exceeds 5,000,000, the fluidity of the polymer is lowered, the wetness to the adherend (for example, polarizing plate) becomes insufficient, and the adherend and the pressure-sensitive adhesive layer of the surface protective film It tends to cause blisters that occur during the period. In addition, a weight average molecular weight means what was obtained by measuring by GPC (gel permeation chromatography).

  The glass transition temperature (Tg) of the (meth) acrylic polymer is preferably 0 ° C. or lower, more preferably −10 ° C. or lower (usually −100 ° C. or higher). When the glass transition temperature is higher than 0 ° C., the polymer does not flow easily, for example, the wettability to the polarizing plate which is an optical member becomes insufficient, and the swelling generated between the polarizing plate and the pressure-sensitive adhesive layer of the surface protective film There is a tendency to cause. In particular, by setting the glass transition temperature to −70 ° C. or lower, an adhesive layer excellent in wettability to the polarizing plate and light peelability can be easily obtained. In addition, the glass transition temperature of a (meth) acrylic-type polymer can be adjusted in the said range by changing the monomer component and composition ratio to be used suitably.

  The polymerization method of the (meth) acrylic polymer is not particularly limited, and can be polymerized by known methods such as solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization, etc. From the viewpoint of characteristics such as low contamination to the adherend (protected body), solution polymerization is a more preferable embodiment. Further, the polymer obtained may be any of a random copolymer, a block copolymer, an alternating copolymer, a graft copolymer, and the like.

<Oxyalkylene group-containing compound>
The pressure-sensitive adhesive composition used in the present invention can also contain an oxyalkylene group-containing compound. By containing the oxyalkylene group-containing compound, it is possible to further develop light peelability. Examples of the oxyalkylene group-containing compound include an organopolysiloxane having an oxyalkylene chain and an oxyalkylene group-containing compound not containing an organopolysiloxane.

  As specific examples of the organopolysiloxane having an oxyalkylene chain, as specific examples of the organopolysiloxane having an oxyalkylene chain in the main chain, for example, as commercial products, the trade names are X-22-4952, X-22. -4272, X-22-6266, KF-6004, KF-889 (above, manufactured by Shin-Etsu Chemical Co., Ltd.), BY16-201, SF8427 (above, made by Toray Dow Corning), IM22 (made by Asahi Kasei Wacker), etc. Is given. Examples of the organosiloxane having an oxyalkylene chain in the side chain include, for example, commercial names KF-351A, KF-352A, KF-353, KF-354L, KF-355A, KF-615A, KF-945. , KF-640, KF-642, KF-643, KF-6022, X-22-6191, X-22-4515, KF-6011, KF-6012, KF-6015, KF-6017, X-22-2516 (Shin-Etsu Chemical Co., Ltd.) SF8428, FZ-2162, SH3749, FZ-77, L-7001, FZ-2104, FZ-2110, L-7002, FZ-2122, FZ-2164, FZ-2203, FZ -7001, SH8400, SH8700, SF8410, SF8422 (above, Toray Dowco , TSF-4440, TSF-4441, TSF-4445, TSF-4450, TSF-4446, TSF-4442, TSF-4460 (manufactured by Momentive Performance Materials), BYK-333, BYK-307, BYK -377, BYK-UV3500, BYK-UV3570 (manufactured by Big Chemie Japan) and the like. These compounds may be used alone or in combination of two or more.

  Specific examples of the oxyalkylene group-containing compound not containing the organopolysiloxane include, for example, polyoxyalkylene alkylamine, polyoxyalkylene diamine, polyoxyalkylene fatty acid ester, polyoxyalkylene sorbitan fatty acid ester, polyoxyalkylene alkyl phenyl ether. , Nonionic surfactants such as polyoxyalkylene alkyl ether, polyoxyalkylene alkyl allyl ether, polyoxyalkylene alkyl phenyl allyl ether; polyoxyalkylene alkyl ether sulfate ester salt, polyoxyalkylene alkyl ether phosphate ester salt, Oxyalkylene alkyl phenyl ether sulfate ester salt, polyoxyalkylene alkyl phenyl ether phosphate ester Anionic surfactants such as salts; other cationic surfactants having polyoxyalkylene chains (polyalkylene oxide chains), amphoteric surfactants, polyether compounds having polyoxyalkylene chains (and derivatives thereof) And acrylic compounds having a polyoxyalkylene chain (and derivatives thereof) and the like. Moreover, you may mix | blend a polyoxyalkylene chain containing monomer as a polyoxyalkylene chain containing compound. Such polyoxyalkylene chain-containing compounds may be used alone or in combination of two or more.

  Specific examples of the polyether compound (polyether component) having a polyoxyalkylene chain include a block copolymer of polypropylene glycol (PPG) -polyethylene glycol (PEG), a block copolymer of PPG-PEG-PPG, Examples thereof include a block copolymer of PEG-PPG-PEG. Examples of the derivative of the polyether compound having a polyoxyalkylene chain include an oxypropylene group-containing compound (PPG monoalkyl ether, PEG-PPG monoalkyl ether, etc.) whose terminal is etherified, and an oxypropylene whose terminal is acetylated. Group-containing compounds (terminal acetylated PPG and the like), and the like.

  Specific examples of the acrylic compound having a polyoxyalkylene chain include a (meth) acrylate polymer having an oxyalkylene group. As said oxyalkylene group, 1-50 are preferable, as for the addition mole number of an oxyalkylene unit, 2-30 are more preferable, and 2-20 are more preferable. The terminal of the oxyalkylene chain may be a hydroxyl group, or may be substituted with an alkyl group, a phenyl group or the like.

  The (meth) acrylate polymer having an oxyalkylene group is preferably a polymer containing (meth) acrylic acid alkylene oxide as a monomer component, and specific examples of the (meth) acrylic acid alkylene oxide include ethylene. Examples of the glycol group-containing (meth) acrylate include methoxy-polyethylene glycol (meth) acrylate types such as methoxy-diethylene glycol (meth) acrylate and methoxy-triethylene glycol (meth) acrylate, ethoxy-diethylene glycol (meth) acrylate, ethoxy -Ethoxy-polyethylene glycol (meth) acrylate type such as triethylene glycol (meth) acrylate, butoxy-diethylene glycol (meth) acrylate, butoxy -Butoxy-polyethylene glycol (meth) acrylate type such as triethylene glycol (meth) acrylate, phenoxy-polyethylene glycol (meth) acrylate type such as phenoxy-diethylene glycol (meth) acrylate, phenoxy-triethylene glycol (meth) acrylate, 2 -Ethylhexyl-polyethylene glycol (meth) acrylate, nonylphenol-polyethylene glycol (meth) acrylate type, methoxy-polypropylene glycol (meth) acrylate type such as methoxy-dipropylene glycol (meth) acrylate, and the like.

  Moreover, other monomer components other than the (meth) acrylic acid alkylene oxide can also be used as the monomer component. Specific examples of other monomer components include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, and 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 , Acrylate and / or methacrylate having an alkyl group having 1 to 14 carbon atoms such as isodecyl (meth) acrylate, n-dodecyl (meth) acrylate, n-tridecyl (meth) acrylate, and n-tetradecyl (meth) acrylate Door and the like.

  Furthermore, as other monomer components other than the (meth) acrylic acid alkylene oxide, carboxyl group-containing (meth) acrylate, phosphoric acid group-containing (meth) acrylate, cyano group-containing (meth) acrylate, vinyl esters, aromatic vinyl compounds , Acid anhydride group-containing (meth) acrylate, hydroxyl group-containing (meth) acrylate, amide group-containing (meth) acrylate, amino group-containing (meth) acrylate, epoxy group-containing (meth) acrylate, N-acryloylmorpholine, vinyl ethers Etc. can be used as appropriate.

  As a more preferred embodiment, the polyoxyalkylene chain-containing compound not containing the organopolysiloxane is a compound having a (poly) ethylene oxide chain at least partially. By blending the (poly) ethylene oxide chain-containing compound, compatibility with the base polymer is improved, bleeding to the adherend is suitably suppressed, and a low-staining adhesive composition is obtained. In particular, when a PPG-PEG-PPG block copolymer is used, a pressure-sensitive adhesive excellent in low contamination can be obtained. As said polyethylene oxide chain containing compound, it is preferable that the weight of the (poly) ethylene oxide chain which occupies for the whole polyoxyalkylene chain containing compound which does not contain the said organopolysiloxane is 5-90 weight%, More preferably, it is 5-85. % By weight, more preferably 5 to 80% by weight, most preferably 5 to 75% by weight.

  Moreover, as a commercial item of the polyoxyalkylene chain containing compound which does not contain the said organopolysiloxane, for example, Adekapluronic 17R-4, Adekapluronic 25R-2 (all are made by ADEKA), Latemul PD-420, LaterumPD -420, Latemul PD-450, Emulgen 120 (manufactured by Kao), Aqualon HS-10, KH-10, Neugen EA-87, EA-137, EA-157, EA-167, EA-177 (above, first Manufactured by Kogyo Seiyaku Co., Ltd.).

  As content of the said oxyalkylene group containing compound, it is 0.01-5. With respect to 100 weight part of adhesive polymers (a main polymer, for example, (meth) acrylic polymer) which comprises the said adhesive composition. 0 parts by weight is preferable, more preferably 0.02 to 2 parts by weight, still more preferably 0.03 to 1.6 parts by weight, and most preferably 0.1 to 0.8 parts by weight. When it is within the above range, it is easy to express light peelability (removability) of the pressure-sensitive adhesive layer (surface protective film) used in the present invention, which is preferable.

<Crosslinking agent>
In the surface protective film of the present invention, the pressure-sensitive adhesive composition preferably contains a crosslinking agent. Moreover, in this invention, it can be set as an adhesive layer using the said adhesive composition. For example, in the case where the pressure-sensitive adhesive composition is an acrylic pressure-sensitive adhesive containing the (meth) acrylic polymer, the constitutional unit, the structural ratio, the selection and addition ratio of the cross-linking agent, etc. are appropriately determined. By adjusting and crosslinking, a pressure-sensitive adhesive layer (surface protective film) having more excellent heat resistance can be obtained.

  As the crosslinking agent used in the present invention, an isocyanate compound, an epoxy compound, a melamine resin, an aziridine derivative, a metal chelate compound, or the like may be used. In particular, the use of an isocyanate compound or an epoxy compound is a preferred embodiment. Moreover, these compounds may be used independently and may be used in mixture of 2 or more types.

  Examples of the isocyanate compounds include aliphatic polyisocyanates such as trimethylene diisocyanate, butylene diisocyanate, hexamethylene diisocyanate (HDI), dimer acid diisocyanate, cyclopentylene diisocyanate, cyclohexylene diisocyanate, isophorone diisocyanate (IPDI), 1, Alicyclic isocyanates such as 3-bis (isocyanatomethyl) cyclohexane, aromatic isocyanates such as 2,4-tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, xylylene diisocyanate (XDI), and the isocyanate compound Allophanate bond, biuret bond, isocyanurate bond, uretdione bond, urea bond, carbodiimide bond, Reton'imin bond, polyisocynate modified products thereof obtained by modifying the like oxadiazinetrione bond. For example, as commercial products, the product names Takenate 300S, Takenate 500, Takenate 600, Takenate D165N, Takenate D178N (above, manufactured by Takeda Pharmaceutical Company Limited), Sumijoule T80, Sumijoule L, Death Module N3400 (above, Sumika Bayer Urethane) Millionate MR, Millionate MT, Coronate L, Coronate HL, Coronate HX (manufactured by Nippon Polyurethane Industry Co., Ltd.) and the like. These isocyanate compounds may be used alone, or may be used in combination of two or more, and a bifunctional isocyanate compound and a trifunctional or higher isocyanate compound may be used in combination. By using a cross-linking agent in combination, it is possible to achieve both tackiness and rebound resistance (adhesion to curved surfaces), and a pressure-sensitive adhesive layer (surface protective film) with better adhesion reliability can be obtained.

  Examples of the epoxy compound include N, N, N ′, N′-tetraglycidyl-m-xylenediamine (trade name: TETRAD-X, manufactured by Mitsubishi Gas Chemical Company) and 1,3-bis (N, N-dioxy). Glycidylaminomethyl) cyclohexane (trade name: TETRAD-C, manufactured by Mitsubishi Gas Chemical Company, Inc.).

  Examples of the melamine resin include hexamethylol melamine. Examples of the aziridine derivative include commercially available product names HDU, TAZM, TAZO (manufactured by Mutual Yakugyo Co., Ltd.) and the like.

  Examples of the metal chelate compound include aluminum, iron, tin, titanium, and nickel as metal components, and acetylene, methyl acetoacetate, and ethyl lactate as chelate components.

  The content of the crosslinking agent used in the present invention is, for example, preferably 0.01 to 20 parts by weight, and 0.1 to 15 parts by weight with respect to 100 parts by weight of the (meth) acrylic polymer. More preferred is 0.5 to 10 parts by weight, and most preferred is 1 to 8 parts by weight. When the content is less than 0.01 parts by weight, the crosslinking formation by the crosslinking agent becomes insufficient, the cohesive force of the resulting pressure-sensitive adhesive layer becomes small, and sufficient heat resistance may not be obtained, It tends to cause glue residue. On the other hand, when the content exceeds 20 parts by weight, the cohesive force of the polymer is large, the fluidity is lowered, the wettability to the adherend (for example, polarizing plate) becomes insufficient, and the adherend and the pressure-sensitive adhesive. There is a tendency to cause blisters generated between the layer (adhesive composition layer). These crosslinking agents may be used alone or in combination of two or more.

<Crosslinking catalyst>
The pressure-sensitive adhesive composition may further contain a cross-linking catalyst for causing any of the above-described cross-linking reactions to proceed more effectively. Examples of such crosslinking catalysts include tin catalysts such as dibutyltin dilaurate and dioctyltin dilaurate, tris (acetylacetonato) iron, tris (hexane-2,4-dionato) iron, tris (heptane-2,4-dionato). ) Iron, tris (heptane-3,5-dionato) iron, tris (5-methylhexane-2,4-dionato) iron, tris (octane-2,4-dionato) iron, tris (6-methylheptane-2) , 4-Dionato) iron, tris (2,6-dimethylheptane-3,5-dionato) iron, tris (nonane-2,4-dionato) iron, tris (nonane-4,6-dionato) iron, tris ( 2,2,6,6-tetramethylheptane-3,5-dionato) iron, tris (tridecan-6,8-dionato) iron, tris (1-phenylbutane-1, -Dionato) iron, tris (hexafluoroacetylacetonato) iron, tris (ethyl acetoacetate) iron, tris (acetoacetate-n-propyl) iron, tris (isopropyl acetoacetate) iron, tris (acetoacetate-n-butyl) ) Iron, Tris (acetoacetate-sec-butyl) iron, Tris (acetoacetate-tert-butyl) iron, Tris (methyl propionyl acetate) iron, Tris (ethyl propionyl acetate) iron, Tris (propionyl acetate-n-propyl) Iron, tris (propionyl acetate isopropyl) iron, tris (propionyl acetate-n-butyl) iron, tris (propionyl acetate-sec-butyl) iron, tris (propionyl acetate-tert-butyl) iron, tris (benzyl acetoacetate) iron , Tris (dimethyl malonate) iron, tris (diethyl malonate) iron, trimethoxy iron Iron-based catalysts such as triethoxy iron, triisopropoxy iron, and ferric chloride can be used. These crosslinking catalysts may be used alone or in combination of two or more.

  Although the content of the crosslinking catalyst is not particularly limited, for example, it is preferably about 0.0001 to 1 part by weight with respect to 100 parts by weight of the (meth) acrylic polymer, 0.001 to 0.5 Part by weight is more preferred. Within the above range, when the pressure-sensitive adhesive layer is formed, the speed of the cross-linking reaction is high, and the pot life of the pressure-sensitive adhesive composition is lengthened.

  Further, the pressure-sensitive adhesive composition may contain other known additives, for example, powders such as lubricants, colorants, pigments, plasticizers, tackifiers, low molecular weight polymers, surface lubrication. Agent, leveling agent, antioxidant, corrosion inhibitor, light stabilizer, UV absorber, polymerization inhibitor, silane coupling agent, antistatic agent, inorganic or organic filler, metal powder, particulate, foil It can be added as appropriate depending on the purpose of using the product.

<Optical surface protective film with separator>
The optical surface protective film with a separator (surface protective film) of the present invention is formed by forming the pressure-sensitive adhesive layer on at least one surface of a base film, and in that case, the pressure-sensitive adhesive composition is crosslinked. Although it is generally performed after application of the adhesive composition, it is also possible to transfer the adhesive layer comprising the crosslinked adhesive composition to a substrate film or the like.

  The method for forming the pressure-sensitive adhesive layer on the base film is not particularly limited. For example, the pressure-sensitive adhesive layer is formed by applying the pressure-sensitive adhesive composition (solution) to the base film and removing the polymerization solvent by drying. It is produced by forming on a base film. Thereafter, curing may be performed for the purpose of adjusting the component transfer of the pressure-sensitive adhesive layer or adjusting the crosslinking reaction. Moreover, when producing a surface protective film by applying the pressure-sensitive adhesive composition on the base film, the pressure-sensitive adhesive composition contains at least one polymerization solvent other than the polymerization solvent so that the surface protective film can be uniformly applied. A new solvent may be added.

  Moreover, as a formation method of the adhesive layer at the time of manufacturing the surface protection film of this invention, the well-known method used for manufacture of adhesive tapes is used. Specific examples include roll coating, gravure coating, reverse coating, roll brushing, spray coating, air knife coating, extrusion coating using a die coater, and the like.

  The surface protective film of the present invention is usually produced so that the pressure-sensitive adhesive layer has a thickness of 3 to 100 μm, preferably about 5 to 50 μm. It is preferable for the thickness of the pressure-sensitive adhesive layer to be within the above range because it is easy to obtain an appropriate balance between removability and adhesiveness.

  In addition, the surface protective film of the present invention preferably has a total thickness of 8 to 300 μm, more preferably 10 to 200 μm, and most preferably 20 to 100 μm. Within the above range, the adhesive properties (removability, adhesiveness, etc.), workability, and appearance properties are excellent and a preferred embodiment is obtained. In addition, the said total thickness means the sum total of the thickness containing all layers, such as a base film, an adhesive layer, a separator, and another layer.

<Separator>
The surface protective film of the present invention has a pressure-sensitive adhesive layer on at least one surface of the base film, and has a separator on the surface opposite to the surface in contact with the pressure-sensitive adhesive layer of the base film. The polyester base material has a release layer and a polyester base material, the polyester base material has a cavity, the polyester base material has a thickness of 25 to 100 μm, and 180 ° with respect to the pressure-sensitive adhesive layer of the separator. The trigger peel force is 0.7 N / 50 mm or less. For the purpose of protecting the pressure-sensitive adhesive surface of the pressure-sensitive adhesive layer, the separator is used to bond the separator to the surface of the pressure-sensitive adhesive layer. In particular, the separator has a specific thickness and a cavity, so that the stiffness of the separator itself can be increased. It can be kept low, has excellent releasability and workability when peeling the separator from the surface of the pressure-sensitive adhesive layer, and can provide cushioning due to cavities, such as glue dents that may occur after pressure-sensitive adhesive coating This is a preferred embodiment.

<Polyester base material>
The polyester-based substrate (sometimes simply referred to as “substrate”) is not particularly limited as long as it is a polyester-based film that can protect the pressure-sensitive adhesive layer and has a cavity. For example, polyethylene terephthalate film, polyethylene A naphthalate film, a polybutylene terephthalate film, etc. are mentioned.

  The thickness of the said polyester-type base material is 25-100 micrometers, Preferably it is 30-80 micrometers, More preferably, it is 40-70 micrometers. It is preferable for it to be in the above-mentioned range since it is excellent in workability for bonding to the pressure-sensitive adhesive layer, and peelability and workability for the pressure-sensitive adhesive layer. In addition, when the thickness of the base material exceeds 100 μm, the stiffness (rigidity) of the separator itself becomes strong, and the peelability and workability are inferior.

  If necessary, the polyester base material can be subjected to various surface treatments such as corona discharge treatment, or various surface treatments such as embossing. If necessary, fillers (inorganic fillers, organic fillers, etc.), anti-aging agents, antioxidants, UV absorbers, antistatic agents, lubricants, plasticizers, colorants (pigments, dyes, etc.), etc. These various additives may be blended.

  The void ratio is preferably 15% (volume%) or more, more preferably 18% or more, and still more preferably 20% or more with respect to the volume of the polyester base material. When the void ratio is 15% or more, the cushioning property of the separator is improved, and a filler (for example, polyethylene terephthalate (PET)) included in the base material film constituting the optical surface protective film or the polyester base material constituting the separator Unevenness due to the filler) can be absorbed, and the occurrence of glue marks due to the separator or the like can be suppressed. Moreover, since the stiffness (rigidity) of the separator is lowered, the peelability of the separator is improved. In view of the strength of the separator and the like, the void ratio is preferably 40% or less, and more preferably 30% or less.

  The shape of the cavity of the polyester-based substrate is spherical, elliptical, or thread-like, and preferably takes a dispersed form. The dispersion diameter is preferably 0.01 to 100 μm, and more preferably 0.05 to 30 μm. Within the above range, the separator has strength, is excellent in cushioning properties, and is excellent in peelability of the separator. The shape of the cavity can be observed from the cross section of the substrate with a scanning electron microscope.

<Release layer>
The release layer has adhesion to the polyester-based substrate and has releasability with respect to the pressure-sensitive adhesive layer, and can be formed from a release agent composition. Although it does not restrict | limit especially as said mold release agent composition, For example, long-chain alkyl type compounds, such as silicone compounds, such as a dimethylsiloxane and a diphenylsiloxane, a silicone resin, a fluororesin, an ashioresin, etc. can be used.

  Furthermore, the release agent composition may contain other known additives such as antistatic agents, powders such as colorants, pigments, surfactants, plasticizers, and tackifiers. , Low molecular weight polymers, surface lubricants, leveling agents, antioxidants, corrosion inhibitors, light stabilizers, UV absorbers, polymerization inhibitors, silane coupling agents, inorganic or organic fillers, metal powders, particulates, etc. Can be added as appropriate according to the intended use.

<Preparation of separator>
The separator is formed on the polyester base material using the release agent composition.

  The method for forming the release layer on the polyester-based substrate is not particularly limited. For example, the release agent composition solution is applied to the substrate, and the polymerization solvent is dried and removed to form the release layer. It is produced by forming on a base material. Thereafter, curing may be performed for the purpose of adjusting the component transfer of the release layer. Further, when the release agent composition is applied onto the substrate to produce a release layer, the release agent composition contains at least one polymerization solvent other than the polymerization solvent so that it can be uniformly applied onto the substrate. A new solvent may be added.

  Moreover, as a formation method of the said release layer, the well-known method used for manufacture of a release layer is used. Specific examples include roll coating, gravure coating, reverse coating, roll brushing, spray coating, air knife coating, extrusion coating using a die coater, and the like.

  The thickness of the release layer is typically 1 to 200 nm, preferably 5 to 100 nm, more preferably 10 to 50 nm. When the thickness of the release layer is too small, the release effect by the release layer is weak, and it becomes difficult to peel the separator, and therefore the work of attaching the optical surface protective film may be difficult. On the other hand, if it is too thick, it may affect the contamination of the pressure-sensitive adhesive layer of the optical surface protective film.

  Examples of commercial products of the separator include Crisper K7211-50 μm, Crisper K7211-38 μm (above, manufactured by Toyobo Co., Ltd.), PET50 (K2411) PAT1 8LK, PET50 (K2411) PAT19 9K (above, manufactured by Lintec). .

<Lamination of optical surface protective film and separator>
The optical surface protective film with a separator of the present invention has a form in which the release layer of the separator is bonded to the surface of the pressure-sensitive adhesive layer of the optical surface protective film. A known method is used for the bonding.

<Optical member>
In this invention, the optical surface protection film which peeled the said separator from the surface of the adhesive layer of the said optical surface protection film with a separator can be stuck on an optical member, and an optical member can be protected. Since the separator is excellent in cushioning properties, it is hard to generate dents and has good peelability, and the optical surface protective film is excellent in appearance quality (appearance), so that it is processed, transported and shipped. Since it can be used for surface protection applications such as time (surface protective film), it is useful for protecting the surface of the optical member (polarizing plate or the like).

  Hereinafter, several examples related to the present invention will be described, but the present invention is not intended to be limited to those shown in the specific examples. In the following description, “parts” and “%” are based on weight unless otherwise specified. Further, the blending amount (addition amount) in the table is shown.

  Each characteristic in the following description was measured or evaluated as follows.

<Measurement of porosity of polyester base material constituting separator>
After taking a photo of a cross section of the polyester base material with a scanning electron microscope, trace the cavity of the cross-sectional area on the tracing film, perform image processing on the filled figure with an image analyzer, and calculate the void ratio (%) as the area ratio. This value was expressed as the void ratio (% by volume) as it was.
Scanning electron microscope used: S-510 scanning electron microscope manufactured by Hitachi, Ltd. Image analysis processing apparatus used: Luzex IID manufactured by Nireco Corporation

<Measurement of separator thickness>
The thickness of the separator (separator thickness) is the total thickness of the polyester base material and the release layer, and was measured using R1-205 manufactured by Ozaki Mfg. Co., Ltd.

<Measurement of (meth) acrylic polymer glass transition temperature (Tg)>
The glass transition temperature (Tg) (° C.) was determined by the following formula using the following literature values as the glass transition temperature Tgn (° C.) of the homopolymer of each monomer.
Formula: 1 / (Tg + 273) = Σ [Wn / (Tgn + 273)]
(Wherein, Tg (° C.) is the glass transition temperature of the copolymer, Wn (−) is the weight fraction of each monomer, Tgn (° C.) is the glass transition temperature of the homopolymer of each monomer, and n is the type of each monomer. Represents.)
Literature values:
2-ethylhexyl acrylate (2EHA): -70 ° C
Butyl acrylate (BA): -55 ° C
2-hydroxyethyl acrylate (HEA): -15 ° C
Acrylic acid (AA): 106 ° C
In addition, as a reference value, “Synthesis / design of acrylic resin and development of new application” (published by Central Management Development Center Publishing Department) was referred.

<Measurement of weight average molecular weight (Mw) of (meth) acrylic polymer>
The weight average molecular weight (Mw) of the (meth) acrylic polymer to be used was measured using a GPC device (HLC-8220GPC) manufactured by Tosoh Corporation. The measurement conditions are as follows.
Sample concentration: 0.2% by weight (THF solution)
Sample injection volume: 10 μl
Eluent: THF
Flow rate: 0.6 ml / min
Measurement temperature: 40 ° C
column:
Sample column; TSKguardcolumn SuperHZ-H (1) + TSKgel SuperHZM-H (2)
Reference column; TSKgel SuperH-RC (1)
Detector: Differential refractometer (RI)
The weight average molecular weight was determined in terms of polystyrene.

<Presence or absence of dents on the adhesive layer surface>
Under a dark room fluorescent lamp, the separator was peeled off from the surface of the pressure-sensitive adhesive layer of the optical surface protective film, light was reflected on the surface of the pressure-sensitive adhesive layer, and it was confirmed by visual observation that there was no dent. The case where there was no dent was marked as ◯, and the case where there was a dent was marked as x.

<Measurement of separator peeling force>
As shown in FIG. 2, the glass 5 (S9213, which is obtained by cutting the optical surface protective film 3 with a separator into a size of 50 mm in width and 100 mm in length and bonding a double-sided tape 4 (Nitto Denko Corporation, No. 500). The surface of the base film 22 constituting the optical surface protective film 3 with a separator was pressure-bonded onto Matsunami Glass Industrial Co., Ltd.) at a pressure of 0.25 MPa and a speed of 0.3 m / min.
Subsequently, single-sided adhesive tape 6 (No. 720, manufactured by Nitto Denko Corporation, width 50 mm) was cut to a length of 50 mm. The pressure-sensitive adhesive surface of the single-sided pressure-sensitive adhesive tape 6 was pressure-bonded with a hand roller onto the separator 1 having a width of 50 mm of the optical surface protective film 3 with a separator so that the end portion protruded by 1 mm. This was left under conditions of 23 ° C. and 50% RH for 10 seconds. Thereafter, the maximum stress applied at the beginning of peeling when the single-sided adhesive tape 6 was peeled off at a speed of 0.3 m / min in the 180 ° direction by an autograph was used as a peeling force (N / 50 mm).

  The trigger peel force (pickup force) is 0.7 N / 50 mm or less, preferably 0.68 N / 50 mm or less, and more preferably 0.65 N / 50 mm or less. When the trigger peel force exceeds 0.7 N / 50 mm, when a thick separator is used, it takes time to peel the separator from the surface of the pressure-sensitive adhesive layer of the optical surface protective film. It is inferior in property and is not preferable. On the other hand, if the trigger peel force is too low, the surface of the pressure-sensitive adhesive layer of the optical surface protective film may not be sufficiently protected, so that it is preferably 0.2 N / 50 mm or more.

<Preparation of (meth) acrylic polymer (A)>
In a four-flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser, 100 parts by weight of 2-ethylhexyl acrylate (2EHA), 4 parts by weight of 2-hydroxyethyl acrylate (HEA), 2, Charge 2'-azobisisobutyronitrile (AIBN) 0.2 part by weight and ethyl acetate 205 part by weight, introduce nitrogen gas with gentle stirring, and keep the liquid temperature in the flask at around 63 ° C. A polymerization reaction was carried out for 4 hours to prepare a (meth) acrylic polymer (A) solution (about 35% by weight). The (meth) acrylic polymer (A) had a weight average molecular weight of 650,000 and Tg of −68 ° C.

<Preparation of (meth) acrylic polymer (B)>
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser, 95 parts by weight of butyl acrylate (BA), 5 parts by weight of acrylic acid (AA), and 2,2′-azo as a polymerization initiator Charge 0.1 parts by weight of bisisobutyronitrile and 234 parts by weight of ethyl acetate, introduce nitrogen gas while gently stirring, and perform a polymerization reaction for 6 hours while maintaining the liquid temperature in the flask at around 65 ° C. ( A (meth) acrylic polymer (B) solution (30% by weight) was prepared. The (meth) acrylic polymer (B) had a weight average molecular weight (Mw) of 1.1 million and a glass transition temperature (Tg) of −47 ° C.

[Preparation of acrylic adhesive (1) solution]
The (meth) acrylic polymer (A) solution (35% by weight) is diluted with ethyl acetate to 29% by weight, and 500 parts by weight (100 parts by weight of solid content) of this solution is used as a crosslinking agent with a trifunctional isocyanate compound. Isocyanurate of certain hexamethylene diisocyanate (Coronate HX: C / HX, manufactured by Nippon Polyurethane Co., Ltd.) 4 parts by weight (solid content 4 parts by weight), dibutyltin dilaurate as a crosslinking catalyst (“Sn” in Table 2, 1% by weight) Ethyl acetate solution) 1.5 parts by weight (solid content 0.015 parts by weight) was added, and the mixture was stirred at about 25 ° C. for about 1 minute to prepare an acrylic pressure-sensitive adhesive (1) solution.

[Preparation of acrylic adhesive (2) solution]
The (meth) acrylic polymer (B) solution (30% by weight) is diluted with ethyl acetate to 29% by weight, and 500 parts by weight (100 parts by weight of solid content) of this solution is used as a crosslinking agent. 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, epoxy equivalent: 110, number of functional groups: 4, trade name “TETRAD-C”: T / C, manufactured by Mitsubishi Gas Chemical Company) 6 parts by weight (solid 6 parts by weight) was added and mixed and stirred to prepare an acrylic pressure-sensitive adhesive (2) solution.

[Preparation of acrylic adhesive (3) solution]
The (meth) acrylic polymer (A) solution (35% by weight) is diluted to 29% by weight with ethyl acetate, and an isocyanate crosslinking agent (as a crosslinking agent) is added to 500 parts by weight (100 parts by weight of solid content) of this solution. Isocyanurate of hexamethylene diisocyanate (trade name “Coronate HX”: C / HX, manufactured by Nippon Polyurethane) 5 parts by weight (solid content 5 parts by weight), dibutyltin dilaurate (1% by weight ethyl acetate solution) as a crosslinking catalyst 3 Parts by weight (solid content: 0.03 parts by weight), polyoxyalkylene chain-containing compound (Aqualon HS-10, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) not containing the organopolysiloxane additive, 0.3 parts by weight (solid content 0) .3 parts) was added and mixed and stirred to prepare an acrylic pressure-sensitive adhesive (3) solution.

<Example 1>
[Preparation of antistatic film]
Antistatic by diluting 10 parts by weight of an antistatic agent (manufactured by Solvex, Microsolver RMd-142, mainly composed of tin oxide and polyester resin) with a mixed solvent consisting of 30 parts by weight of water and 70 parts by weight of methanol An agent solution was prepared.
The obtained antistatic agent solution was applied on a polyethylene terephthalate (PET) film (thickness: 38 μm) as a base film using a Mayer bar, and the solvent was removed by drying at 130 ° C. for 1 minute. An antistatic layer (thickness: 0.2 μm) was formed to produce an antistatic treatment film.

[Preparation of optical surface protective film with separator]
The acrylic pressure-sensitive adhesive (1) solution was applied to the surface opposite to the antistatic surface of the antistatic film and heated at 130 ° C. for 2 minutes to form a pressure-sensitive adhesive layer having a thickness of 15 μm. . Next, on the surface of the pressure-sensitive adhesive layer, Crisper K7211-50 μm (made by Toyobo Co., Ltd., specific gravity of polyester-based substrate: 1.1 g / cm ³ , porosity of polyester-based substrate). : 20%, thickness 50 μm) was used for bonding, and a surface protective film for optical use with a separator was prepared.

<Examples 2-5, Comparative Examples 1-4>
As shown in Table 2, the acrylic pressure-sensitive adhesive (1) solution used in Example 1 or, instead, the acrylic pressure-sensitive adhesive (2) solution or the acrylic pressure-sensitive adhesive (3) solution was used. An optical surface protective film with a separator was produced in the same manner as in Example 1 except that the separator described in 3 was used.

  Tables 1 to 3 show the results of the above-described blending contents, various measurements and evaluations on the optical surface protective films with separators according to the examples and comparative examples. In addition, the compounding quantity in a table | surface shows an active ingredient.

  From Table 3 above, in all examples, by making the porosity and thickness of the polyester base material constituting the separator within a desired range, it is excellent in peelability and workability, and can further prevent the occurrence of dents. It could be confirmed. Further, in the examples, since no dents are generated on the surface of the pressure-sensitive adhesive layer, when bonding to the adherend, there is no bubble, and the optical surface protective film is bonded to the adherend. It is possible to provide an optical surface protective film having excellent inspectability at the time of inspection. On the other hand, in Comparative Examples 1 to 3, since the void ratio of the polyester base material constituting the separator is not included in the desired range, the stiffness (rigidity) of the separator is strong, and the peelability and workability are poor. Comparative Example 4 Then, since the thickness of the polyester base material is not included in the desired range, the cushioning property cannot be exhibited, and the occurrence of dents due to the separator was confirmed.

  The separator-provided optical surface protective film with a separator is used at the time of production or transportation of an optical member used as a component of a liquid crystal display panel, a plasma display panel (PDP), an organic electroluminescence (EL) display, or the like. It is suitable as a surface protective film for protecting the optical member. In particular, it is useful as an optical surface protective film applied to optical members such as polarizing plates (polarizing films) for liquid crystal display panels, wave plates, retardation plates, optical compensation films, brightness enhancement films, light diffusion sheets, and reflective sheets. It is.

1: Separator 2: Optical surface protective film 3: Optical surface protective film 4 with separator: Double-sided adhesive tape 5: Glass 6: Single-sided adhesive tape 11: Polyester base material 12: Release layer 21: Adhesive layer 22: Base film

Claims (4)

An optical surface protective film having an adhesive layer on at least one surface of the base film, and an optical surface protective film with a separator having a separator on the surface opposite to the surface in contact with the adhesive layer of the base film. ,
The separator has a release layer and a polyester base material,
The polyester base material has a cavity,
The polyester base material has a thickness of 25 to 100 μm,
The optical surface protective film with a separator, wherein the separator has a 180 ° -triggered peeling force with respect to the pressure-sensitive adhesive layer of 0.7 N / 50 mm or less.   The optical surface protective film with a separator according to claim 1, wherein a void ratio is 15% or more with respect to a volume of the polyester base material.   The optical surface protective film with a separator according to claim 1 or 2, wherein the base film is a polyester film. The said adhesive layer is formed from the adhesive composition containing a (meth) acrylic-type polymer, The surface protection film for optics with a separator in any one of Claims 1-3 characterized by the above-mentioned.

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