JP5211607B2 - Separator-less protective film - Google Patents

Description

  The present invention relates to a separatorless protective film that does not have a separator that covers an adhesive layer, and more particularly relates to a separatorless protective film in which the antistatic layer is less deteriorated when unwound from a raw fabric.

  In general, the protective film is bonded to the protected body with an adhesive layer provided on the protective film in order to prevent scratches, contamination, and the like on the protected body. For example, such a protective film is bonded to an optical member such as a polarizing plate or a retardation plate to be bonded to a liquid crystal cell via an adhesive layer in order to protect it from scratches and dirt. Then, the protective film is peeled off and removed at the stage where the surface protection is no longer necessary by bonding the optical member to the liquid crystal cell.

  As such a protective film, for example, one having a configuration in which an adhesive layer, a base film and an antistatic layer are laminated in this order is known. The adhesive layer is a layer having a function of closely adhering to the protected body, the base film is a layer having a function of holding the protective film, and the antistatic layer is formed when the protective film is peeled from the protected body. This layer has a function of preventing dust or the like from adhering to the surface of the object to be protected or destruction of the TFT element or the like of the liquid crystal cell due to generated static electricity.

  The protective film having such a layer structure can be further roughly classified into a separator holding type protective film and a separatorless type protective film. The separator holding type protective film is a type of protective film further comprising a separator that covers the adhesive layer until the protective film is used. On the other hand, the separatorless protective film is a type of protective film that does not have a separator that covers the adhesive layer. Among them, the separatorless type protective film has an advantage that the cost can be reduced because the separator is not disposed when the protective film is used.

  The separatorless type protective film is usually stored in a rolled state until the protective film is used. At this time, since the separator is not provided, the pressure-sensitive adhesive layer is in direct contact with another layer (for example, an antistatic layer). Therefore, in order to produce a more practical separatorless protective film, it is necessary to prevent the adhesive layer from being excessively adhered to other layers. Therefore, a separatorless protective film using a heat-crosslinking resin for the adhesive layer is conventionally known. For example, Patent Document 1 discloses a technique for manufacturing a separatorless protective film having an adhesive layer using a heat-crosslinking resin.

JP 2002-19039 A

  However, a separatorless protective film provided with an adhesive layer using a heat-crosslinking resin has the following problems. That is, when the separatorless protective film is wound into a roll shape, if the adhesive layer and the antistatic layer are in direct contact with each other, when the raw material is unwound, the antistatic layer There is a problem that the antistatic property is lowered.

  The present invention has been made in view of the above circumstances, and a main object of the present invention is to provide a separator-less protective film in which the antistatic layer is less deteriorated when unwound from the original fabric.

  In order to solve the above-mentioned problems, in the present invention, a base film and an adhesive layer forming material formed on one surface of the base film and containing an adhesive and an ionizing radiation cross-linking resin are cross-linked. A separatorless protective film comprising: an adhesive layer formed on the substrate film; and an antistatic layer formed on the other surface of the substrate film.

  According to the present invention, by providing an adhesive layer formed using an ionizing radiation cross-linking resin, it is possible to provide a separatorless protective film in which the antistatic layer is less deteriorated when unwound from the original fabric.

  In the said invention, it is preferable that the said ionizing radiation crosslinkable resin is electron beam crosslinkable resin or ultraviolet-ray crosslinkable resin. It is because it can be set as a separatorless type protective film with less deterioration of the antistatic layer.

In the above invention, the difference between the surface specific resistance value of the antistatic layer after unwinding from the original fabric and the surface specific resistance value of the antistatic layer before winding up to the original fabric is 3.0 × 10 It is preferably ⁸ Ω / □ or less. It is because it can be set as a separatorless type protective film with little deterioration of the antistatic layer.

  Moreover, in this invention, the separatorless type | mold protective film original fabric characterized by winding up the separatorless type | mold protective film mentioned above in roll shape is provided.

  According to the present invention, by using the separatorless protective film described above, it is possible to obtain a separatorless protective film original with little deterioration of the antistatic layer during unwinding.

  Further, in the present invention, an antistatic layer forming step for forming an antistatic layer on one surface of the base film, and an adhesive and an ionizing radiation cross-linking resin on the other surface of the base film. An adhesive layer forming step for forming an adhesive layer and a base film having the antistatic layer and the adhesive layer are wound into a roll by applying the coating liquid for forming the adhesive layer and irradiating with ionizing radiation. A separatorless type protective film raw material manufacturing method characterized by having a winding step.

  According to the present invention, by forming an adhesive layer using an ionizing radiation cross-linking resin, it is possible to obtain a separatorless type protective film original fabric with little deterioration of the antistatic layer during unwinding.

  Moreover, in this invention, it has the unwinding process which unwinds a separatorless type protective film from the separatorless type protective film original fabric obtained by the manufacturing method of the separatorless type protective film original fabric mentioned above. A method for producing a separatorless protective film is provided.

  According to the present invention, the separatorless type protection provided with the antistatic layer excellent in antistatic property by using the separatorless type protective film raw material obtained by the above-described method for producing the separatorless type protective film raw material. A film can be obtained.

  In this invention, when unwinding from an original fabric, there exists an effect that a separatorless type | mold protective film with little deterioration of an antistatic layer can be obtained.

  Hereinafter, a separatorless protective film, a separatorless protective film raw material, a method for producing a separatorless protective film raw material, and a method for producing a separatorless protective film will be described in detail.

A. Separator-less protective film First, the separator-less protective film of the present invention will be described. The separatorless protective film of the present invention is a pressure-sensitive adhesive formed by crosslinking a base film and a pressure-sensitive adhesive layer-forming material containing an adhesive and an ionizing radiation cross-linking resin, which is formed on one surface of the base film. A layer, and an antistatic layer formed on the other surface of the base film.

  According to the present invention, by providing an adhesive layer formed using an ionizing radiation cross-linking resin, it is possible to provide a separatorless protective film in which the antistatic layer is less deteriorated when unwound from the original fabric. The following can be considered as the reason why a separatorless protective film with little deterioration of the antistatic layer can be obtained. That is, when forming a pressure-sensitive adhesive layer using a conventional heat-crosslinkable resin, the heat-crosslinkable resin is crosslinked by heat treatment to form a pressure-sensitive adhesive layer, and then the separatorless protective film is wound into a roll, Next, the roll-shaped raw fabric is aged (aged). Usually, before the crosslinking reaction by heat is completed, the separatorless protective film is wound up in a roll shape. Therefore, even if it is wound into a roll and the adhesive layer and the antistatic layer are in direct contact with each other, the crosslinking reaction proceeds. As a result, a phenomenon in which the antistatic component of the antistatic layer is transferred to the antistatic layer or a phenomenon in which the adhesion between the antistatic layer and the adhesive layer becomes excessively strong occurs. Thereby, when the separatorless type protective film is unwound from the original fabric, it is considered that the antistatic property of the antistatic layer is lowered due to the adhesive layer.

  In contrast, in the present invention, the adhesive layer is formed using an ionizing radiation cross-linking resin. When the ionizing radiation cross-linking resin is used, the cross-linking reaction can be completed in a short time when the irradiation of ionizing radiation is completed. As a result, even when the separatorless type protective film is rolled up and the adhesive layer and the antistatic layer are in direct contact, the antistatic component of the antistatic layer shifts to the antistatic layer, There is an advantage that a phenomenon in which the adhesion between the antistatic layer and the adhesive layer becomes excessively strong does not occur. As a result, a separatorless protective film with little deterioration of the antistatic layer when unwound from the raw fabric can be obtained. Such a phenomenon is a phenomenon peculiar to the separatorless protective film, and more specifically, it can be said to be a phenomenon peculiar to the separatorless protective film in which the adhesive layer and the antistatic layer are in direct contact. The present invention solves such a specific problem by providing an adhesive layer using an ionizing radiation cross-linking resin.

  Next, the separatorless protective film of the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing an example of the separatorless protective film of the present invention. A separatorless protective film 10 shown in FIG. 1 is formed on a base film 1 and one surface of the base film 1 and crosslinks an adhesive layer forming material containing an adhesive and an ionizing radiation cross-linking resin. And the antistatic layer 3 formed on the other surface of the base film 1. Moreover, as shown in FIG. 2 mentioned later, in this invention, the separatorless type protective film original fabric 20 formed by winding up the separatorless type protective film 10 in roll shape is provided.

In the present invention, the “separator-less protective film” refers to a protective film that covers the surface of the adhesive layer and does not have a separator that prevents the adhesive layer from sticking to other members before the protective film is used. Say.
Hereinafter, the separatorless protective film of the present invention will be described for each configuration.

1. First, the adhesive layer used in the present invention will be described. The pressure-sensitive adhesive layer used in the present invention is formed on one surface of a substrate film, and is formed by crosslinking a pressure-sensitive adhesive layer-forming material containing a pressure-sensitive adhesive and an ionizing radiation crosslinkable resin. Hereinafter, the adhesive layer used in the present invention will be described in detail.

(1) Adhesive layer forming material The adhesive layer forming material used in the present invention contains at least an adhesive and an ionizing radiation-crosslinking resin.

(I) Pressure-sensitive adhesive The pressure-sensitive adhesive used in the present invention is not particularly limited as long as it has a desired pressure-sensitive adhesive property, and examples thereof include acrylic, urethane-based, rubber-based, and silicone-based pressure-sensitive adhesives. Can do. In the present invention, an acrylic pressure-sensitive adhesive is particularly preferable. This is because it is excellent in transparency, durability and heat resistance, and is low in cost. Examples of the acrylic pressure-sensitive adhesive include an acrylate copolymer obtained by copolymerizing an acrylate ester with another monomer.

  Examples of the acrylate ester include ethyl acrylate, acrylate-n-butyl, acrylate-2-ethylhexyl, isooctyl acrylate, isononyl acrylate, hydroxylethyl acrylate, propylene glycol acrylate, acrylamide, and glycidyl acrylate. Etc. In the present invention, ethyl acrylate, acrylate-n-butyl, acrylate-2-ethylhexyl, and the like are particularly preferable. This is because the adhesiveness to the protected object is good. Moreover, the said acrylic ester may be used independently, and multiple may be used in mixture.

  Examples of the other monomer include, for example, methyl acrylate, methyl methacrylate, styrene, acrylonitrile, vinyl acetate, acrylic acid, methacrylic acid, itaconic acid, hydroxylethyl acrylate, hydroxylethyl methacrylate, propylene glycol acrylate, Examples include acrylamide, methacrylamide, glycidyl acrylate, glycidyl methacrylate, dimethylaminoethyl methacrylate, tert-butylaminoethyl methacrylate, and n-ethylhexyl methacrylate. In the present invention, n-ethylhexyl methacrylate is particularly preferable. Moreover, the said other monomer may be used independently, and two or more may be mixed and used.

  The weight average molecular weight (Mw) of the acrylic ester copolymer used as the acrylic pressure-sensitive adhesive used in the present invention is particularly limited as long as the acrylic pressure-sensitive adhesive exhibits a desired adhesive force. However, it is preferably in the range of 200,000 to 2,500,000, and more preferably in the range of 600,000 to 2,200,000. The weight average molecular weight is a value in terms of polystyrene when measured by gel permeation chromatography (GPC).

(Ii) Ionizing radiation crosslinkable resin Next, the ionizing radiation crosslinkable resin used in the present invention will be described. The ionizing radiation crosslinking resin used in the present invention is not particularly limited as long as an adhesive layer capable of exhibiting desired adhesiveness can be obtained. For example, electron beam crosslinking resin, ultraviolet crosslinking resin, infrared crosslinking resin , A visible light crosslinkable resin, an X-ray crosslinkable resin, a γ-ray crosslinkable resin, and the like. In particular, an electron beam crosslinkable resin and an ultraviolet ray crosslinkable resin can be suitably used. Generally, the electron beam crosslinkable resin and the ultraviolet ray crosslinkable resin are the same in terms of components, except that the latter requires a photopolymerization initiator and a photosensitizer when being crosslinked. The electron beam cross-linking resin does not require a photopolymerization initiator as compared with the ultraviolet cross-linking resin, and thus has an advantage of excellent workability. The ultraviolet-crosslinking resin has an advantage that a general-purpose ultraviolet irradiation device can be used.

  Examples of the electron beam cross-linking resin include a monomer having a polymerizable functional group that undergoes a reaction that promotes an increase in molecular weight such as polymerization when irradiated with an electron beam. Among these, in the present invention, a monomer having two or more functional groups is preferable. Examples of the monomer include β-carboxyethyl acrylate, isobornyl acrylate, octyl / decyl acrylate, ethoxylated phenyl acrylate, dipropylene glycol diacrylate, 1,6-hexanediol diacrylate, tripropylene glycol diacrylate, PO-modified neo Pentyl glycol diacrylate, modified bisphenol A diacrylate, tricyclodecane dimethanol diacrylate, pentaerythritol triacrylate, trimethylolpropane triacrylate, trimethylolpropane ethoxytriacrylate, trimethylolpropane triacrylate, polyether Triacrylate, glycerin propoxytriacrylate, dipentaerythritol hexaacrylate, Taerisuto - Le tetraacrylate, pentaerythritol et list - Le tetraacrylate, mention may be made of ditrimethylolpropane tetraacrylate, among others trimethylolpropane triacrylate are preferred.

  The amount of the electron beam crosslinkable resin contained in the adhesive layer forming material varies depending on the type of the pressure sensitive adhesive and the electron beam crosslinkable resin. It is preferable to be within the range of 70 parts by weight, particularly within the range of 10 parts by weight to 60 parts by weight, and particularly within the range of 30 parts by weight to 50 parts by weight.

  As described above, as the ultraviolet crosslinkable resin, the same material as that of the electron beam crosslinkable resin can be used.

(Iii) Other components The pressure-sensitive adhesive layer-forming material used in the present invention contains at least a pressure-sensitive adhesive and an ionizing radiation-crosslinking resin. For example, when the ionizing radiation crosslinking resin is an ultraviolet crosslinking resin, the adhesive layer forming material usually further contains a photopolymerization initiator and a photosensitizer.

  Examples of the photopolymerization initiator include 1-hydroxy-cyclohexyl-phenyl-ketone 2-methyl-1 [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2-benzyl-2-dimethyl. Amino-1- (4-morpholinophenyl) -butanone-1,2,2-dimethoxy-1,2-diphenylethane-1-one, 1- [4- (2-hydroxyethoxy) -phenyl] -2- Hydroxy-2-methyl-1-propan-1-one, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, bis (η5-2,4-cyclopentadien-1-yl) -bis (2 , 6-difluoro-3- (1H-pyrrol-1-yl) -phenyl) titanium and the like, among which 1-hydroxy-cyclohexyl-sulfur Nyl-ketone, 2-methyl-1 [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone 1 is preferred. The amount of the photopolymerization initiator contained in the adhesive layer forming material is, for example, in the range of 1 to 10 parts by weight, particularly in the range of 3 to 8 parts by weight, with respect to 100 parts by weight of the UV-crosslinking resin. In particular, it is preferable to be within the range of 4 to 6 parts by weight.

  Examples of the photosensitizer include benzoin sensitizers such as benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin, and aromatic ketone sensitizers such as benzophenone, Michler's ketone, fluorenone, xanthone, and thioxanthone. Etc. The amount of the photosensitizer contained in the adhesive layer forming material is, for example, in the range of 1 to 30 parts by weight, particularly in the range of 5 to 20 parts by weight, with respect to 100 parts by weight of the UV-crosslinking resin. In particular, the content is preferably in the range of 10 to 15 parts by weight.

(2) Adhesive layer Next, the adhesive layer used in the present invention is formed by crosslinking the above-mentioned adhesive layer forming material. The thickness of the pressure-sensitive adhesive layer varies depending on the application of the separatorless protective film, but is, for example, in the range of 3 μm to 200 μm, in particular in the range of 4 μm to 100 μm, particularly in the range of 5 μm to 50 μm. preferable.

  The pressure-sensitive adhesive layer used in the present invention usually has a degree of adhesiveness that can be adhered to at least a protected body. On the other hand, it is preferable that the pressure-sensitive adhesive layer has a pressure-sensitive adhesive property capable of suppressing deterioration of the antistatic layer when the separatorless protective film is unwound from the original fabric. The adhesive strength of the adhesive layer is, for example, in the range of 0.01 N / 25 mm to 1.0 N / 25 mm, in particular in the range of 0.05 N / 25 mm to 0.5 N / 25 mm, particularly 0.1 N / 25 mm to 0.00. It is preferably within the range of 4N / 25mm. The adhesive strength is as follows. First, a strip-shaped test piece having a width of 25 mm and a length of 150 mm is cut from a separatorless protective film, and then a SUS304 made of SUS304 under the conditions in accordance with the standard of JIS Z0237. Finally, the test piece can be measured by peeling it off in the length direction of the test piece under conditions of a peeling angle of 180 °, a peeling speed of 300 mm / min, and room temperature. Further, for such 180 ° peel strength measurement, for example, a universal testing machine 5565 manufactured by Instron can be used. In the present invention, it is preferable that the pressure-sensitive adhesive layer has the above-described pressure-sensitive adhesive strength even after the separator-less protective film is unwound from the original fabric.

2. Antistatic Layer The antistatic layer used in the present invention will be described. The antistatic layer used in the present invention is formed on the surface of the base film opposite to the above-mentioned adhesive layer. The antistatic layer used in the present invention is not particularly limited as long as a desired antistatic property can be exhibited, and the same antistatic layer as that used for a general protective film can be used. In addition, the antistatic layer used in the present invention usually contains at least an antistatic agent, and optionally contains a binder.

  The antistatic agent is not particularly limited as long as it can exhibit a desired antistatic property, and examples thereof include quaternary ammonium salts, pyridium salts, primary to tertiary amino acids. Cationic antistatic agent having a cationic group such as a group; Anionic antistatic agent having an anionic group such as sulfonate group, sulfate ester base, phosphate ester base; Amphoteric charge such as amino acid and amino acid sulfate ester Surfactant type antistatic agents such as inhibitors, amino alcohol-based, glycerin-based, polyethylene glycol-based nonionic antistatic agents; Furthermore, a polymer surfactant type antistatic agent obtained by increasing the molecular weight of a monomer component containing a surfactant type antistatic agent may be used.

  Other examples of the antistatic agent include, for example, antimony indium tin oxide (ATO), indium tin oxide (ITO), organic compound fine particles surface-treated with gold and / or nickel. Can do. Furthermore, a conductive polymer such as polyacetylene, polypyrrole, polythiophene, polyaniline, polyphenylene vinylene, polyacene, or derivatives thereof may be used.

  Among these, in the present invention, a cationic antistatic agent and a conductive polymer having a quaternary ammonium salt are preferable, and a cationic antistatic agent having a quaternary ammonium salt is particularly preferable. It is because it is excellent in antistatic property and transparency. Examples of the cationic antistatic agent having a quaternary ammonium salt include fourth compounds such as dilauryl diethoxyl type quaternary ammonium salt, dicetyl diethoxyl type quaternary ammonium salt, and distearyl quaternary ammonium salt. Examples thereof include those having a quaternary ammonium salt. Specific examples of such cationic antistatic agents include Colcoat NR-121X manufactured by Colcoat Co., Ltd. On the other hand, examples of the conductive polymer include polyaniline, polypyrrole, polyacetylene, polythiophene, poly (p-phenylene), poly (p-phenylene vinylene) and the like. Specific examples of such a conductive polymer include Colcoat SP-2001 manufactured by Colcoat Co., Ltd.

  In the case of using a polymer antistatic agent such as a polymer surfactant antistatic agent and a conductive polymer, the weight average molecular weight of the polymer antistatic agent is, for example, in the range of 5,000 to 300,000. In particular, it is preferably within the range of 50,000 to 200,000. The weight average molecular weight is a value in terms of polystyrene when measured by gel permeation chromatography (GPC).

  The content of the antistatic agent in the antistatic layer varies depending on the use of the separatorless protective film, but is preferably in the range of 4 wt% to 99 wt%, for example, 10 wt% to It is preferably within the range of 80% by weight.

  The antistatic layer used in the present invention may contain a binder as necessary. The binder is not particularly limited as long as it is a resin that can stably hold the antistatic agent, and examples thereof include thermoplastic resins, thermosetting resins, and photosensitive resins. .

  Examples of the thermoplastic resin include polyacrylic acid, polymethacrylic acid, polyacrylate, polymethacrylate, polyolefin, polystyrene, polyamide, polyimide, polyvinyl chloride, polyvinyl alcohol, polyvinyl butyral, polycarbonate, polyester, polyurethane, and the like. Can be mentioned.

  As the thermosetting resin, for example, a monomer having a curing reactive functional group that can be cured by causing a large molecular weight reaction such as polymerization or crosslinking to proceed with the same functional group or another functional group by heating. , Oligomers and polymers. Specific examples include monomers, oligomers and the like having an alkoxy group, a hydroxyl group, a carboxyl group, an amino group, an epoxy group, a hydrogen bond forming group, and the like.

  The photosensitive resin has a polymerizable functional group that causes a reaction that causes a large molecule such as polymerization or dimerization, for example, directly upon receiving light irradiation or indirectly through the action of an initiator. Mention may be made of monomers, oligomers and polymers. Further, a photopolymerization initiator may be used together with the photosensitive resin. As said photosensitive resin, the radical polymerizable thing which has ethylenically unsaturated bonds, such as an acryl group, a vinyl group, and an allyl group, and the photo cationic polymerizable thing of an epoxy group containing compound can be mentioned, for example. Specifically, as the radical polymerizable compound, methyl (meth) acrylate, ethyl (meth) acrylate, ethylhexyl (meth) acrylate, styrene, methylstyrene, N-vinylpyrrolidone, polymethylolpropane tri (meth) acrylate, hexanedio- (Meth) acrylate, tripropylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,6-hexanediol Examples thereof include monofunctional monomers such as (meth) acrylate and neopentyl glycol di (meth) acrylate, and polyfunctional monomers. In addition, as a cationically polymerizable compound having an epoxy group, a compound having one epoxy group such as phenyl glycidyl ether or butyl glycidyl ether, hexanediol diglycidyl ether, tetraethylene glycol diglycidyl ether, trimethylolpropane triglycidyl ether, bisphenol Examples thereof include compounds having two or more epoxy groups such as A diglycidyl ether, bisphenol F diglycidyl ether, and novolac type epoxy compound.

  Among them, in the present invention, the binder is preferably a thermoplastic resin, and particularly preferably polyester or polyacrylate. It is because it is excellent in transparency and adhesion to the substrate film.

  The weight average molecular weight (Mw) of the binder is not particularly limited as long as it can stably hold the antistatic agent, but it is within the range of 3,000 to 300,000, for example, 5 among them. , Preferably in the range of 100,000 to 100,000. The weight average molecular weight is a value in terms of polystyrene when measured by gel permeation chromatography (GPC).

  The thickness of the antistatic layer is, for example, preferably in the range of 0.05 μm to 5.00 μm, more preferably in the range of 0.10 μm to 3.00 μm, and particularly preferably in the range of 0.50 μm to 1.50 μm. If the film thickness is too small, the desired antistatic property may not be exhibited. If the film thickness is too large, the light transmittance may be deteriorated.

The antistatic property of the antistatic layer used in the present invention can be evaluated by the surface specific resistance value of the antistatic layer. The surface resistivity of the antistatic layer is, for example, preferably 1.0 × 10 ¹¹ Ω / □ or less, more preferably 1.0 × 10 ¹⁰ Ω / □ or less, and 1.0 × 10 ⁹ Ω / □ or less. Further preferred. This is because, within the above range, sufficient antistatic properties can be exhibited. In the present invention, the surface specific resistance value is determined by measuring the surface of the antistatic layer of the separatorless protective film according to JIS K7194 using a digital insulation meter (for example, Loresta-GP MCP-T610, manufactured by Mitsubishi Chemical Corporation). It can be measured. In the present invention, it is preferable that the antistatic layer has the above-mentioned surface specific resistance value even after the separatorless protective film is unwound from the original fabric.

Further, in the present invention, the surface specific resistance value of the antistatic layer after unwinding from the original fabric is usually larger than the surface specific resistance value of the antistatic layer before winding up the original fabric. The difference between the two is preferably small, for example, 3.0 × 10 ⁸ Ω / □ or less, and more preferably 2.5 × 10 ⁸ Ω / □ or less. It is because it can be set as a separatorless type protective film with little deterioration of the antistatic layer.

3. Next, the base film used in the present invention will be described. The base film used in the present invention holds the above-described adhesive layer, antistatic layer, and the like. As a base film used for this invention, if it has desired flexibility and transparency, it will not specifically limit, The same thing as the base film used for a general protective film is used. be able to. Especially, in this invention, it is preferable that the transparency of a base film is high. This is because an optical inspection can be performed with high accuracy in a state where a separatorless protective film is attached to an object to be protected such as an optical member.

  Specific examples of the base film include olefin resins such as polyethylene, polypropylene, polyvinyl alcohol or ethylene-vinyl alcohol copolymer, polyfluorinated ethylene, polyvinylidene fluoride, or tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer. Fluorine-based resins such as polyvinyl chloride or polyvinyl chloride such as polyvinylidene chloride, acrylic resins such as polymethyl methacrylate, sulfone resins such as polyethersulfone, ketone-based resins such as polyetheretherketone And thermoplastic polyester resins such as polyethylene terephthalate and polyethylene naphthalate, polyimide resins, and polyamide resins. In the present invention, a thermoplastic polyester resin is particularly preferable, and polyethylene terephthalate is particularly preferable. It is because it is excellent in transparency.

  The base film used in the present invention has a surface treatment such as corona treatment and plasma treatment and a primer (primer) on the surface of the base film in order to improve the adhesion with the adhesive layer and / or the antistatic layer. May be applied.

  The thickness of the base film is not particularly limited as long as it can be bonded with good adhesion when bonded to a protected body and can be sufficiently protected from scratches, etc. Although it is suitably set according to the application of the separatorless type protective film, for example, it is preferably in the range of 12 μm to 100 μm, in particular in the range of 16 μm to 50 μm, particularly in the range of 25 μm to 38 μm. This is because if it is thicker than the above range, it may be difficult to bond to the protected body with good adhesion. Further, if it is thinner than the above range, it may be difficult to sufficiently protect from scratches and the like.

4). Separator-less protective film The separator-less protective film of the present invention has at least a base film, an adhesive layer, and an antistatic layer. Further, as described above, the separatorless protective film of the present invention has little deterioration of the antistatic layer when it is unwound from the original fabric.

  The separatorless protective film of the present invention is preferably excellent in light transmittance. This is because an optical inspection can be performed with high accuracy in a state where a separatorless protective film is attached to an object to be protected such as an optical member. The total light transmittance of the separatorless protective film is, for example, preferably in the range of 85% to 99%, and more preferably in the range of 90% to 99%. In the present invention, the total light transmittance can be measured with an integrating sphere turbidimeter (for example, NDH2000, manufactured by Nippon Denshoku Industries Co., Ltd.) according to JIS K-7361. On the other hand, the haze of the separatorless protective film is, for example, preferably in the range of 0.5% to 4.5%, and more preferably in the range of 0.5% to 3.0%. In the present invention, haze can be measured with an integrating sphere turbidimeter (for example, NDH2000 manufactured by Nippon Denshoku Industries Co., Ltd.) according to JIS K-7136.

  Examples of the use of the separatorless protective film of the present invention include use of optical members. That is, the separatorless protective film of the present invention is preferably used for protecting the surface of the optical member. Specific examples of the optical member include an optical member for a liquid crystal cell, an optical member for a lens, an optical member for optical nanoimprint, and the like, among which an optical member for a liquid crystal cell is preferable. This is because, in recent years, liquid crystal cells have been greatly increased in screen size and definition, and improvement in antistatic properties has been demanded. Specific examples of the optical member for a liquid crystal cell include a deflection plate and a retardation plate. Specific examples of the optical member for lenses include a microlens array. Specific examples of the optical member for optical nanoimprinting include a template for optical nanoimprinting. On the other hand, applications other than optical members include, for example, steel plate protection, window glass protection, and plastic protection (for example, a personal computer housing).

5. Method for Producing Separator-less Protective Film The method for producing the separator-less protective film of the present invention is not particularly limited as long as a desired protective film can be obtained. The manufacturing method of the separatorless protective film will be described in detail in “C. Specifically, a separatorless protective film can be obtained by performing an antistatic layer forming step and an adhesive layer forming step described later.

B. Next, the separatorless protective film original fabric of the present invention will be described. The separatorless protective film original fabric of the present invention is obtained by winding the separatorless protective film described above into a roll.

  According to the present invention, by using the separatorless protective film described above, it is possible to obtain a separatorless protective film original with little deterioration of the antistatic layer during unwinding.

  As shown in FIG. 2 described above, the separator-less type protective film raw material of the present invention includes a base film 1, an adhesive layer 2 formed on one surface of the base film 1, and a base film 1. The separator-less protective film 10 having the antistatic layer 3 formed on the other surface is wound up in a roll shape.

  About the separatorless type protective film used for this invention, since it is the same as that of the content described in said "A. separatorless type protective film", description here is abbreviate | omitted. Moreover, the separatorless type protective film original fabric of the present invention is usually wound so that the adhesive layer and the antistatic layer are in direct contact with each other.

  Although the width | variety of the separatorless type protective film original fabric of this invention changes with the magnitude | sizes etc. of a to-be-protected body, it is about 30 cm-2.0 m normally. Moreover, although the diameter of the separatorless type | mold protective film original fabric of this invention changes with uses etc. of a separatorless type | mold protective film original fabric, it is about 40 cm-2.5 m normally. Moreover, it is preferable that the separator-less type protective film original fabric of the present invention has unwinding strength described in “D. Method for producing separator-less type protective film”.

C. Next, the manufacturing method of the separatorless type protective film original fabric of the present invention will be described. The separatorless protective film raw material manufacturing method of the present invention includes an antistatic layer forming step of forming an antistatic layer on one surface of a base film, and an adhesive on the other surface of the base film. A pressure-sensitive adhesive layer forming step of forming a pressure-sensitive adhesive layer by applying a coating liquid for forming a pressure-sensitive adhesive layer containing an agent and an ionizing radiation-crosslinking resin and irradiating with ionizing radiation; and the antistatic layer and the pressure-sensitive adhesive layer And a winding step of winding the substrate film in a roll shape.

  According to the present invention, by forming an adhesive layer using an ionizing radiation cross-linking resin, it is possible to obtain a separatorless type protective film original fabric with little deterioration of the antistatic layer during unwinding.

FIG. 3 is an explanatory view for explaining a method for producing a separatorless protective film original fabric according to the present invention. In the manufacturing method of the separatorless type protective film raw material shown in FIG. 3, first, an antistatic layer-forming coating solution is applied on one surface of the base film 1 and dried to prevent antistatic. Layer 3 is formed (FIG. 3A). Next, on the other surface of the base film 2, a pressure-sensitive adhesive layer-forming coating solution containing an adhesive and an ionizing radiation cross-linking resin is applied, dried, and then irradiated with ionizing radiation 4. The adhesive layer 2 is formed (FIG. 3B). Next, the base film 1 having the antistatic layer 3 and the pressure-sensitive adhesive layer 3 is wound into a roll shape to obtain a separatorless protective film raw fabric 20 (FIG. 3C). In particular, in the present invention, it is preferable to carry out roll to roll from the supply of the base film 1 to the production of the separatorless protective film raw fabric 20.
Hereinafter, the manufacturing method of the separatorless type protective film raw material of this invention is demonstrated for every process.

1. Antistatic Layer Forming Step The antistatic layer forming step in the present invention is a step of forming an antistatic layer on one surface of the substrate film. Usually, an antistatic layer is formed by applying an antistatic layer-forming coating solution containing a material constituting the antistatic layer and applying the coating solution onto the surface of the base film and drying.

  In the present invention, either the antistatic layer forming step or the adhesive layer forming step described later may be performed first, or both steps may be performed simultaneously. Further, the antistatic agent and the base film used in the present invention are the same as the contents described in the above “A. Separator-less protective film”, and thus the description thereof is omitted here.

  The coating solution for forming an antistatic layer used in the present invention usually contains an antistatic agent and a solvent. The solvent is not particularly limited as long as it can dissolve and disperse the antistatic agent. For example, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, benzene, toluene, xylene, chlorobenzene, tetrahydrofuran , Methyl cellosolve, ethyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, ethyl acetate, 1,4-dioxane, 1,2-dichloroethane, dichloromethane, chloroform, methanol, ethanol, isopropanol Water, distilled water, ion-exchanged water, and the like.

  The solid content concentration of the coating solution for forming the antistatic layer varies depending on the kind of the antistatic agent and the like, but is, for example, 10.0% by weight or less, and particularly in the range of 0.5% to 5.0% by weight. It is preferable to be within.

  The application method of the antistatic layer forming coating solution is not particularly limited, and a known application method can be used. Specifically, roll coating method, gravure coating method, micro gravure coating method, reverse coating method, roll brush method, spray coating method, air-knife coating method, impregnation method, curtain coating method, die coating method, doctor blade method, The coat which mentions the comma coat method etc. can be performed. Examples of the drying method for the applied coating solution for forming an antistatic layer include a hot air drying method and an infrared drying method.

  In the present invention, the coating solution for forming the antistatic layer is applied so that the thickness of the antistatic layer after drying becomes the thickness of the antistatic layer described in “A. Separator-less protective film”. It is preferable to do.

2. Next, the adhesive layer forming step in the present invention will be described. In the pressure-sensitive adhesive layer forming step in the present invention, a pressure-sensitive adhesive layer-forming coating solution containing a pressure-sensitive adhesive and an ionizing radiation-crosslinking resin is applied onto the surface of the base film opposite to the above-described antistatic layer, and ionization is performed. It is a step of forming an adhesive layer by irradiating with radiation.

  The adhesive layer-forming coating liquid used in the present invention usually contains an adhesive layer-forming material containing an adhesive and an ionizing radiation cross-linking resin, and a solvent. About the adhesive layer forming material used for this invention, since it is the same as that of the content described in the said "A. separator-less type protective film", description here is abbreviate | omitted. The solvent is not particularly limited as long as it can dissolve and disperse the ionizing radiation cross-linking resin, and the same solvent as the solvent for the antistatic layer forming coating solution described above may be used. it can.

  The solid content concentration of the coating liquid for forming the adhesive layer varies depending on the type of ionizing radiation cross-linking resin, but is within the range of 10 wt% to 40 wt%, for example, and 15 wt% to 30 wt%. % Is preferable.

  The method for applying the coating liquid for forming the adhesive layer is not particularly limited, and a known coating method can be used. Specifically, roll coating method, gravure coating method, micro gravure coating method, reverse coating method, roll brush method, spray coating method, air knife coating method, impregnation method, curtain coating method, die coating method, doctor blade method In addition, a coat including a comma coat method can be used, and among them, a roll coat method, a reverse coat method, a die coat method, and a comma coat method are preferable. Examples of the method for drying the applied adhesive layer forming coating solution include a hot air drying method and an infrared drying method.

  In this invention, after apply | coating the coating liquid for adhesion layer formation to a base film and making it dry, ionizing radiation crosslinking type resin contained in the material for adhesion layer formation is bridge | crosslinked by ionizing radiation irradiation. The ionizing radiation used varies depending on the type of ionizing radiation cross-linking resin, and examples thereof include electron beams, ultraviolet rays, infrared rays, visible rays, X-rays and γ rays.

  Examples of electron beam accelerators used when irradiating an electron beam include a Cochloftwalton type, a bandegraph type, a resonant transformation type, an insulated core transformer type, a linear type, a dynamitron type, and a high frequency type. Can be mentioned. In this invention, it is preferable to irradiate an electron beam so that an adhesion layer may have the adhesive force described in said "A. separator-less type protective film". The irradiation energy is, for example, preferably within a range of 1 Mrad (megaradian) to 7 Mrad, and more preferably within a range of 3 Mrad to 5 Mrad.

Examples of the ultraviolet irradiator used when irradiating with ultraviolet rays include an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a carbon arc, a xenon arc, and a metal halide lamp. In this invention, it is preferable to irradiate an ultraviolet-ray so that an adhesion layer may have the adhesive force described in said "A. separator-less type protective film". The irradiation energy, for example in the range of ^{20mJ / cm 2 ~1,000mJ / cm 2} , preferably in the range Of these the ^{30mJ / cm 2 ~150mJ / cm 2} .

  In the present invention, when the above-described antistatic layer contains a photosensitive resin, the ionizing radiation for the antistatic layer and the ionizing radiation for the adhesive layer may be irradiated separately, or both may be irradiated simultaneously. good. In the present invention, the pressure-sensitive adhesive layer-forming coating solution is used so that the thickness of the pressure-sensitive adhesive layer after irradiation with ionizing radiation is equal to the thickness of the pressure-sensitive adhesive layer described in “A. Separator-less protective film”. It is preferable to apply.

  In addition, for example, when the substrate film does not have solvent resistance to the solvent of the coating liquid or does not have the heat resistance required for the drying treatment for removing the solvent, An adhesive layer may be formed on the film. As an example of the transfer method, for example, by forming an adhesive layer on a release film obtained by releasing the surface of a PET film with a fluorine release agent, a silicone release agent or a long-chain alkyl release agent. First, a transfer sheet is prepared, then the transfer sheet and a substrate film are laminated, and finally, a peelable film is peeled off.

3. Next, the winding process in the present invention will be described. The winding process in this invention is a process of winding up the base film which has the said antistatic layer and the said adhesion layer in roll shape. In the present invention, a separatorless type protective film original fabric is usually obtained in which the adhesive layer and the antistatic layer are in direct contact.

  About the method of winding up the base film which has an antistatic layer and an adhesion layer, the tension | tensile_strength at the time of winding, etc., it is the same as that in the case of the general protective film original fabric. In particular, in the present invention, it is preferable to carry out by roll to roll from the supply of the base film to the production of the separator-less type protective film original. Further, the obtained separatorless protective film original fabric is the same as the content described in “B. Separatorless protective film original fabric”.

D. Next, a method for producing a separatorless protective film of the present invention will be described. The method for producing a separatorless protective film of the present invention includes an unwinding step of unwinding the separatorless protective film from the separatorless protective film original obtained by the method for producing a separatorless protective film. It is characterized by.

  According to the present invention, the separatorless type protection provided with the antistatic layer excellent in antistatic property by using the separatorless type protective film raw material obtained by the above-described method for producing the separatorless type protective film raw material. A film can be obtained.

  FIG. 4 is an explanatory view for explaining the method for producing the separatorless protective film of the present invention. The separatorless protective film shown in FIG. 4 is produced from the separatorless protective film original 20 obtained by the method described in “C. Separatorless protective film original” described above. It has an unwinding step of unwinding the loess-type protective film 10.

  The unwinding strength at the time of unwinding the separatorless protective film from the raw material of the separatorless protective film is, for example, 0.20 N / 25 mm or less, and particularly within the range of 0.05 N / 25 mm to 0.13 N / 25 mm. It is preferable. This is because unwinding defects can be effectively prevented within the above range.

  The unwinding strength is a strip shape having a width of 25 mm and a length of 150 mm from the separatorless protective film original fabric, and a state in which two layers of separatorless protective films are stacked (antistatic agent layer / base Material film / adhesive layer / antistatic agent layer / base film / adhesive layer in a layered state) is cut out to form a test piece, and one separatorless protective film of the test piece is used as the other separator. It can be measured by peeling it from the loess-type protective film in the length direction of the test piece under the conditions of a peeling angle of 180 °, a peeling speed of 300 mm / min, and room temperature. Further, for such 180 ° peel strength measurement, for example, a universal testing machine 5565 manufactured by Instron can be used.

  The unwinding speed of the separatorless protective film is preferably selected as appropriate according to the characteristics of the members constituting the separatorless protective film. In the present invention, the unrolled separatorless protective film may be cut before being brought into close contact with the protected body, or may be cut after being brought into close contact with the protected body. preferable. It is because it can prevent that adhesive force falls.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.

  Hereinafter, the present invention will be described in more detail with reference to examples.

[Example 1]
(1) Formation of antistatic layer A single-sided corona-treated PET (S105 manufactured by Toray Industries, Inc.) having a thickness of 38 μm is prepared as a base film, and the coating for forming an antistatic layer having the following composition is applied to the corona-treated surface of the single-sided corona-treated PET. The coating solution was applied by a gravure printing method under a drying condition of 50 ° C. for 30 seconds so that the film thickness after drying was 1 μm, and an antistatic layer was formed on the substrate film.

(Composition of coating solution for antistatic layer formation)
・ Quaternary ammonium salt + binder (NR-121X made by Colcoat) 100 parts by weight ・ Isopropyl alcohol 2000 parts by weight

(2) Formation of pressure-sensitive adhesive layer On the surface of the base film opposite to the antistatic layer, the pressure-sensitive adhesive layer-forming coating liquid having the following composition is dried at 100 ° C. for 1 minute under a dry condition. Coating was performed by a die coating method so as to be 15 μm.

(Coating liquid for forming adhesive layer)
・ Acrylic ester-based adhesive (ATR340 manufactured by Seiden Chemical Co., Ltd.) 100 parts by weight ・ UV cross-linked resin (M-309, manufactured by Toagosei Co., Ltd.) ・ Photopolymerization initiator (Irgacure 184 manufactured by Ciba Specialty Chemicals)
2.9 parts by weight / toluene 25 parts by weight

Next, using a high pressure mercury lamp, ultraviolet irradiation of 30 mJ / cm ² was performed to crosslink the ultraviolet crosslinking resin to obtain an adhesive layer. Thereby, a separatorless type protective film was obtained.

[Example 2 and Example 3]
A separatorless protective film was obtained in the same manner as in Example 1 except that the ultraviolet irradiation energy was changed as shown in Table 1.

[Comparative Example 1]
First, in the same manner as in Example 1, an antistatic layer was formed on a base film. Next, on the surface of the base film opposite to the antistatic layer, an adhesive layer-forming coating solution having the following composition was applied by a die coating method. Thereafter, heat treatment was performed at 100 ° C. for 1 minute for thermal crosslinking, and the film was allowed to stand in an oven at 40 ° C. for 72 hours, thereby performing an aging treatment to obtain an adhesive layer having a film thickness of 15 μm. Thereby, a separatorless type protective film was obtained.

(Coating liquid for forming adhesive layer)
・ Acrylic acid ester adhesive (ATR340 manufactured by Seiden Chemical) 100 parts by weight ・ Isocyanate-based crosslinking agent (K200 manufactured by Seiden Chemical) 3.57 parts by weight ・ Metal chelating agent (M2 manufactured by Seiden Chemical) 0.06 weight Parts ・ Toluene 33 parts by weight

[Comparative Example 2]
A separatorless protective film was obtained in the same manner as in Comparative Example 1 except that the adhesive layer-forming coating solution having the following composition was used.

(Coating liquid for forming adhesive layer)
・ 100 parts by weight of acrylic ester adhesive (ATR340 manufactured by Seiden Chemical) ・ 3.57 parts by weight of isocyanate-based crosslinking agent (K200 manufactured by Seiden Chemical) ・ 0.12 by weight of metal chelating agent (M2 manufactured by Seiden Chemical) Parts ・ Toluene 33 parts by weight

[Evaluation]
About the separatorless type | mold protective film obtained in Examples 1-3 and Comparative Examples 1-2, unwinding strength evaluation, antistatic property evaluation, and peeling strength evaluation were performed.

(1) Evaluation of unwinding strength The separatorless protective film was wound up under the condition of 30 kg / m to prepare a separatorless protective film original fabric. Next, the separator-less protective film is a strip having a width of 25 mm × length of 150 mm, and two separator-less protective films are stacked (antistatic agent layer / base film / A layer of adhesive layer / antistatic agent layer / base film / adhesive layer) is cut out and used as a test piece, and one separatorless protective film of the test piece is used as the other separatorless type protection. The unwinding strength was measured by peeling the film in the length direction of the test piece under the conditions of a peeling angle of 180 °, a peeling speed of 300 mm / min, and room temperature. Note that a universal testing machine 5565 manufactured by Instron was used for the 180 ° peel strength measurement. The results are shown in Table 1.

(2) Evaluation of antistatic property Using two separatorless protective films peeled in the unwinding strength evaluation, the antistatic layer that was in direct contact with the adhesive layer and the adhesive layer that was in direct contact with the antistatic layer The surface resistivity was measured. The surface specific resistance value was measured using a digital insulation meter (Mitsubishi Chemical Corporation: Loresta-GP MCP-T610) in accordance with JIS K7194 on the surface of the antistatic layer and the adhesive layer. The results are shown in Table 1. The “initial state” in Table 1 is the surface specific resistance value of the antistatic layer and the adhesive layer in the separatorless protective film before producing the original fabric.

(3) Peel strength evaluation (adhesive strength evaluation)
A strip-shaped test piece having a width of 25 mm and a length of 150 mm is cut from the separatorless type protective film, then laminated to a SUS304 made of SUS304 under the conditions conforming to the standard of JIS Z0237, and finally tested. The peel strength (adhesive strength) was measured by peeling the piece in the length direction of the test piece under the conditions of a peel angle of 180 °, a peel speed of 300 mm / min, and room temperature. The measurement was carried out 24 hours later (room temperature and humidity), 1 week later (room temperature and humidity, temperature 50 ° C., humidity 80RH%), and 1 month later (room temperature and humidity, temperature 50 ° C., humidity 80RH). Note that a universal testing machine 5565 manufactured by Instron was used for the 180 ° peel strength measurement. The results are shown in Table 2.

  As shown in Table 1, in Examples 1 to 3, the antistatic property of the antistatic layer after peeling was substantially the same as the initial state. From this, it was confirmed that when the separatorless protective film was unwound from the raw material of the separatorless protective film, a separatorless protective film with little deterioration of the antistatic layer was obtained. In Examples 1 to 3, the unwinding strength was low as compared with Comparative Examples 1 and 2. From this, it was confirmed that a separator-less protective film original fabric having good unwinding properties was obtained.

  On the other hand, in Comparative Example 1, it was confirmed that the antistatic layer after peeling does not have antistatic properties. At the same time, considering that the peeled adhesive layer has antistatic properties, the antistatic component of the antistatic layer is in direct contact with the separatorless protective film raw material of Comparative Example 1 when unrolled. It was confirmed that it would shift to the layer. Similarly, in Comparative Example 2, it was confirmed that the antistatic layer deteriorated significantly when the separatorless protective film was unwound from the separatorless protective film original.

It is a schematic sectional drawing which shows an example of the separatorless type protective film of this invention. It is a schematic sectional drawing which shows an example of the separatorless type protective film original fabric of this invention. It is explanatory drawing explaining the manufacturing method of the separatorless type protective film original fabric of this invention. It is explanatory drawing explaining the manufacturing method of the separatorless type protective film of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Base film 2 ... Adhesive layer 3 ... Antistatic layer 4 ... Ionizing radiation 10 ... Separator-less type protective film 20 ... Separator-less type protective film original fabric

Claims (5)

A base film, an adhesive layer formed on one surface of the base film, the adhesive layer forming material containing an adhesive and an ionizing radiation crosslinkable resin being previously cross-linked, and the other of the base film A separatorless protective film original roll, which is obtained by winding a separatorless protective film having an antistatic layer formed on the surface of the film into a roll. The separatorless protective film original fabric according to claim 1, wherein the ionizing radiation crosslinking resin is an electron beam crosslinking resin or an ultraviolet crosslinking resin. The difference between the surface specific resistance value of the antistatic layer after unwinding from the original fabric and the surface specific resistance value of the antistatic layer before winding up to the original fabric is 3.0 × 10 ⁸ Ω / □ or less The separator-less type protective film original fabric according to claim 1 or 2, wherein the original film is a separatorless type protective film. An antistatic layer forming step of forming an antistatic layer on one surface of the base film;
An adhesive layer forming step of forming an adhesive layer by applying an adhesive layer forming coating solution containing an adhesive and an ionizing radiation cross-linking resin on the other surface of the base film and irradiating with ionizing radiation When,
And a winding step of winding the base film having the antistatic layer and the adhesive layer in a roll shape. A separatorless mold comprising an unwinding step of unwinding the separatorless protective film from the separatorless protective film original obtained by the method for producing a separatorless protective film according to claim 4. A method for producing a protective film.

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