KR20190101938A - Surface-protective film and optical component attached with the same - Google Patents

Abstract

Provided are a surface protection film, capable of being attached to an optical film having an uneven surface, causing only a little pollution on an attached object, preventing the low pollution property on the object from changing over time, preventing temporal deterioration and having excellent exfoliation electrification prevention performance, and an optical component using the same. The surface protection film (5) comprises: a release agent layer (2) formed on one side of a base film (1) made of transparent resin; and an adhesive layer (4) formed on the other side of the base film (1). The release agent layer (2) contains a silicon-based release agent and an electrification prevention agent (3) made of alkali metallic salt. The components of the electrification prevention agent (3) made of the alkali metallic salt and included in the release agent layer (2) exist only on the surface of the adhesive layer (4).

Description

SURFACE-PROTECTIVE FILM AND OPTICAL COMPONENT ATTACHED WITH THE SAME}

This invention relates to the surface protection film bonded together on the surface of an optical component (henceforth an optical film). More specifically, it is related with providing the surface protection film which has little contamination with a to-be-adhered body, and whose contamination with respect to a to-be-adhered body does not change over time, and the optical component using the same. Moreover, this invention peels at the time of peeling a surface protection film even if the structural member of the polarizing plate which is an optical component is replaced (change from TAC film to acrylic film or polyester film, or from water-based adhesive to UV-curable adhesive). It is providing the surface protection film which suppressed the low voltage, and the optical component with which it was bonded.

Here, the optical component in this invention refers to a polarizing plate, a phase difference plate, the lens film for a display, etc.

When manufacturing and conveying optical products such as polarizing plates, retardation plates, lens films for displays, antireflection films, hard coat films, transparent conductive films for touch panels, and displays using the same, the surface of the optical films The surface protection film is bonded together to the surface to prevent contamination and scratches on the surface in a later step. The external appearance inspection of the optical film which is a product may be performed in the state which bonded the surface protection film to the optical film, in order to reduce the effort of peeling and rebonding the surface protection film and to raise work efficiency.

DESCRIPTION OF RELATED ART Conventionally, the surface protection film which provided the adhesive layer in one side of the base film is generally used in order to prevent a stick | wound or a contamination | pollution in the manufacturing process of an optical product. The surface protection film is bonded to the optical film via the adhesive layer of a non-adhesive force. The non-adhesive force of the pressure-sensitive adhesive layer can be easily peeled off when the used surface protection film is peeled off and removed from the surface of the optical film so that the pressure-sensitive adhesive does not remain attached to the optical film of the product which is the adherend. (So as to prevent the occurrence of pressure-sensitive adhesive residues).

In recent years, in the production process of a liquid crystal display panel, circuit components, such as a driver IC for controlling the display screen of a liquid crystal display, by the peeling charge voltage which arises when peeling and removing the surface protection film bonded on the optical film, The occurrence of breakage or damage to the orientation of the liquid crystal molecules is small but occurs.

In addition, in order to reduce the power consumption of the liquid crystal display panel, the driving voltage of the liquid crystal material is lowered, and with this, the breakdown voltage of the driver IC is also lowered. In recent years, it is required to make peeling electrification voltage into the range of +0.7 kV--0.7 kV.

In addition, in the conventional polarizing plate, a triacetyl cellulose film (TAC film) was bonded to both sides of a polarizer made of polyvinyl alcohol (PVA) impregnated with iodine with a water-based adhesive in order to protect the polarizer. Instead of the TAC film, a polarizing plate using an acrylic film, a cyclic polyolefin film or a polyester film, or a polarizing plate using an ultraviolet curable adhesive instead of an aqueous adhesive is also used. As the constituent material of the polarizing plate changes, the problem that the peeling electrification voltage which arises when peeling and removing a surface protection film becomes higher than when using the polarizing plate of a conventional structure is also raised.

In recent years, with the spread of 3D displays (stereoscopic displays), some FPR (Film Patterned Retarder) films are bonded to the surface of optical films such as polarizing plates. An FPR film is bonded together after peeling off the surface protection film bonded to the surface of optical films, such as a polarizing plate. However, when the surface of optical films, such as a polarizing plate, is contaminated with the adhesive or antistatic agent used for a surface protection film, there exists a problem that a FPR film is hard to adhere | attach. For this reason, the surface protection film used for the said use is calculated | required that the contamination with respect to a to-be-adhered body is small.

On the other hand, in several liquid crystal panel makers, the surface protection film bonded to optical films, such as a polarizing plate, was peeled once and re-bonded in the state which mixed bubbles as a method of evaluation of the contamination property to the adherend of a surface protection film. After heat-processing on predetermined conditions, the method of peeling a surface protection film and observing the surface of a to-be-adhered body is employ | adopted. In such an evaluation method, even if the surface contamination of the adherend is very small, if there is a difference between the surface contamination of the adherend in the portion where the bubble is mixed with the adhesive of the surface protective film, the trace of the bubble may be referred to as bubble stain. Remains as). For this reason, it becomes a very strict evaluation method as an evaluation method of the contamination property to the surface of a to-be-adhered body. In recent years, the surface protection film which has very little contamination with the surface of a to-be-adhered body which can pass the judgment by such a strict evaluation method is calculated | required.

After bonding a surface protection film to the optical film which is a to-be-adhered body, in order to prevent the problem by which the peeling electrification voltage which arises when peeling a surface protection film from a to-be-adhered body is high, the antistatic agent for suppressing peeling electrification voltage is low. The surface protection film using the adhesive layer containing is proposed.

For example, Patent Literature 1 discloses a surface protective film using an adhesive made of an alkyltrimethylammonium salt, a hydroxyl group-containing acrylic polymer, and a polyisocyanate.

In addition, Patent Literature 2 discloses an adhesive composition composed of an ionic liquid and an acrylic polymer having an acid value of 1.0 or less, and adhesive sheets using the same.

In addition, Patent Document 3 discloses an adhesive composition composed of an alkali metal salt treated with an acrylic polymer, a polyether polyol compound, an anion adsorbent compound, and a surface protective film using the same.

In addition, Patent Document 4 discloses an adhesive composition composed of an ionic liquid, an alkali metal salt, a polymer having a glass transition temperature of 0 ° C. or less, and a surface protective film using the same.

Japanese Laid-Open Patent Publication 2005-131957 Japanese Laid-Open Patent Publication 2005-330464 Japanese Laid-Open Patent Publication 2005-314476 Japanese Laid-Open Patent Publication No. 2006-152235

In the surface protection films of the said patent documents 1-4, the antistatic agent is added in the inside of an adhesive layer. Therefore, as the thickness of the pressure-sensitive adhesive layer becomes thicker, and as the elapsed time after the bonding to the adherend passes, the amount of the antistatic agent transferred from the pressure-sensitive adhesive layer to the adherend with respect to the adherend to which the surface protective film is bonded. This tended to increase. Moreover, when the quantity of the antistatic agent which transfers to a to-be-adhered body increases, the external appearance quality of the optical film which is a to-be-adhered body may fall, or the adhesiveness of an FPR film may fall when bonding an FPR film.

Thus, when the thickness of an adhesive layer is made thin in order to reduce the time-lapse change of the antistatic agent which transfers from an adhesive layer to a to-be-adhered body, another problem arises. For example, when used for an optical film having irregularities on the surface, such as a polarizing plate that is anti-glare for preventing glare, the adhesive layer cannot follow the unevenness on the surface of the optical film and bubbles are mixed or optical As the adhesion area of the film and the pressure-sensitive adhesive layer is reduced, there is a problem that the adhesive force is lowered and the surface protective film floats or peels off during use.

In addition, when the amount of the antistatic agent added to the adhesive layer is reduced in order to reduce the aging change of the antistatic agent transferred from the adhesive layer to the adherend, the peeling electrification voltage generated when the surface protective film is peeled off and removed from the adherend becomes high. There is a risk that a phenomenon in which circuit components such as a driver IC is destroyed, or a phenomenon in which the orientation of liquid crystal molecules is damaged, may occur.

This invention is made | formed in view of the said situation, As a surface protection film bonded to the surface of an optical film, it can be bonded also to the optical film with an unevenness | corrugation on the surface, very little contamination to a to-be-adhered body, and time It is an object of the present invention to provide a surface protection film and an optical component using the same, in which low contamination of the adherend does not change even if this passes.

Moreover, this invention peels at the time of peeling a surface protection film even if the structural member of the polarizing plate which is an optical component is replaced (change from TAC film to acrylic film or polyester film, or from water-based adhesive to UV-curable adhesive). An object of the present invention is to provide a surface protective film having a low voltage suppressed and an optical component using the same.

The present inventors earnestly examined in order to solve these problems. In order to reduce the contamination of the adherend and to reduce the change of the contaminant with time, it is necessary to reduce the content of the antistatic agent that is supposed to be the cause of contaminating the adherend. However, when content of an antistatic agent is reduced, the peeling electrification voltage at the time of peeling a surface protection film from a to-be-adhered body becomes high.

The present inventors examined the method of suppressing the peeling electrification voltage at the time of peeling a surface protection film from a to-be-adhered body, without increasing content of an antistatic agent.

MEANS TO SOLVE THE PROBLEM First, the present inventors apply | coat and dry the adhesive composition which does not contain an antistatic agent to one side of a base material, laminate an adhesive layer, and produce the surface protection film which laminated the release agent layer containing an antistatic agent on the other side of a base material. It was. Thereafter, the surface protection film is wound so that the pressure-sensitive adhesive layer is inward to form a roll so that the antistatic agent component contained in the release agent layer is transferred to the surface of the pressure-sensitive adhesive layer and exists only on the surface of the pressure-sensitive adhesive layer. Became. After bonding this surface protection film to the optical film which is a to-be-adhered body, it discovered that peeling electrification voltage at the time of peeling off from a to-be-adhered body is suppressed low, and it is hard to contaminate a to-be-adhered body, and completed this invention.

The surface protection film of this invention coats and dries the adhesive composition which does not contain an antistatic agent on one side of a base material, laminates an adhesive layer, and after laminating the release agent layer containing an antistatic agent on the other side of a base material, By winding a surface protection film so that an adhesive layer may become inner, and making it into roll shape, the antistatic agent component contained in the said peeling agent layer is transferred to the surface of the said adhesive layer. In the present invention, when the surface protective film of the state wound in the roll shape is wound from the roll shape and bonded to the adherend, the contamination to the adherend is suppressed to be low, and the surface protective film can be peeled off from the optical film that is the adherend. It is a technical idea to suppress the peeling electrification voltage at the time of low.

In order to solve the said subject, this invention is a surface protection film by which the peeling agent layer is formed in one surface of the base film which consists of resin which has transparency, and the adhesive layer is formed in the other surface of the said base film, The said release agent layer contains the antistatic agent which consists of alkali metal salts, and a silicone type release agent, and the antistatic agent component which consists of the said alkali metal salt contained in the said release agent layer exists only in the surface of the said adhesive layer, The surface protection film characterized by the above-mentioned. To provide.

Moreover, it is preferable that the said adhesive layer is an acrylic adhesive layer containing the (meth) acrylate copolymer bridge | crosslinked.

Moreover, it is preferable that surface potential at the time of peeling the said adhesive layer in the optical film which is a to-be-adhered body is +0.7 kPa--0.7 kPa.

Moreover, it is preferable that the said base film is wound by roll shape with the said adhesive layer inward so that the said peeling agent layer and the said adhesive layer may contact.

Moreover, this invention provides the optical component by which the said surface protection film is bonded together through the said adhesive layer.

The surface protection film of this invention is a surface protection film bonded together to the surface of the optical film, and can also bond together the optical film with an unevenness | corrugation on the surface.

Moreover, according to this invention, the surface protection film and the optical component using the same can be provided which has very little contamination with a to-be-adhered body, and whose contamination with respect to a to-be-adhered body does not change even over time.

Moreover, according to this invention, even if the structural member of the polarizing plate which is an optical component changes (change from ATC film to an acrylic film, a cyclic polyolefin film, or a polyester film, or changes from an aqueous adhesive to an ultraviolet curable adhesive), surface protection The surface protection film which suppressed the peeling electrification voltage at the time of peeling a film, and the optical component using the same can be provided.

Moreover, the surface protection film wound by the roll shape of this invention is a surface protection film wound by roll shape with the said adhesive layer inward so that a peeling agent layer and an adhesive layer may contact a base film, The antistatic agent which consists of the said alkali metal salt The component is transferred from the release agent layer to the surface of the pressure-sensitive adhesive layer and exists only on the surface of the pressure-sensitive adhesive layer.

That is, in this invention, after bonding the surface protection film rewound from the surface protection film wound by roll shape to a to-be-adhered body, the peeling electrification voltage at the time of peeling a surface protection film from a to-be-adhered body is reduced, and peeling antistatic performance It is characterized by the fact that the change over time and the contamination of the adherend are small, so that the productivity and yield of the optical component as the adherend can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS It is conceptual sectional drawing which shows the surface protection film of the state wound by the roll shape of this invention.
It is conceptual sectional drawing which showed the state which the peeling agent layer and the adhesive layer contacted in the state which wound the surface protection film of this invention in roll shape.
It is sectional drawing which shows one of the Example which bonded the surface protection film of this invention to the optical component.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail based on embodiment.

1 is a conceptual cross-sectional view showing the surface protection film 10 in a state wound in a roll shape of the present invention. The surface protection film 10 of the state wound by the roll shape shown to the right side of FIG. 1 wound the surface protection film 5 which concerns on this invention to roll shape with the adhesive layer 4 inside (surface protection film) Roll body of (5)). In addition, the left side of FIG. 1 is a conceptual sectional drawing which expands and shows the surface protection film 5 rewound from roll shape in the arrow direction in the thickness direction.

This surface protection film 5 has the peeling agent layer 2 containing the antistatic agent 3 which consists of alkali metal salts on one surface of the transparent base film 1, and is an adhesive on the other surface of the base film 1 Layer 4 is formed. The surface protection film 5 which has the peeling agent layer 2 in one surface of the base film 1, and has the adhesive layer 4 in the other surface of a base film, removes the release agent layer 2 and the adhesive layer 4 By contacting with this, the adhesive layer 4 is rolled inward in a roll shape, so that the antistatic agent 3 component contained in the release agent layer 2 is transferred to the surface of the adhesive layer 4, thereby The surface protection film 10 of the state wound by roll shape which exists only in the surface is obtained.

As the base film 1 used for the surface protection film 5 which concerns on this invention, the base film which consists of resin which has transparency and flexibility is used. Thereby, the external appearance inspection of an optical component can be performed in the state which bonded the surface protection film 5 to the optical component which is a to-be-adhered body. As a film which consists of resin which has transparency used as the base film 1, Preferably, polyester films, such as polyethylene terephthalate, polyethylene naphthalate, polyethylene isophthalate, and polybutylene terephthalate, are used. In addition to the polyester film, a film made of other resin can be used as long as it has the required strength and has optical aptitude. The base film 1 may be a non-stretched film, or may be a film uniaxially or biaxially stretched. In addition, you may control the draw ratio of a stretched film, and the oriented angle of the axial direction formed with crystallization of a stretched film to a specific value.

Although the thickness of the base film 1 used for the surface protection film 5 which concerns on this invention is not specifically limited, For example, the thickness of about 12-100 micrometers is preferable, and if it is a thickness of about 20-75 micrometers, it will handle. It is easy to do it and is more preferable.

In addition, you may perform an adhesion | attachment process, such as surface modification by corona discharge, application | coating of an anchor coat agent, on the surface of the base film 1 as needed.

In addition, the release agent layer 2 formed in the surface protection film 5 which concerns on this invention is formed using the release agent containing the antistatic agent 3 which consists of alkali metal salts. As the release agent, a silicone release agent is preferably used.

Examples of the silicone release agent include known silicone release agents such as addition reaction type, condensation reaction type, cationic polymerization type and radical polymerization type. As a product marketed as an addition reaction type silicone type | system | group release agent, KS-776A, KS-847T, KS-779H, KS-837, KS-778, KS-830 (made by Shin-Etsu Chemical Co., Ltd.), SRX- 211, SRX-345, SRX-357, SD7333, SD7220, SD7223, LTC-300B, LTC-350G, LTC-310 (made by Toray Dow Corning). As a product marketed as a condensation reaction type, SRX-290, SYLOFF-23 (made by Toray Dow Corning Co., Ltd.), etc. are mentioned, for example. As a product commercially available as a cation polymerization type, TPR-6501, TPR-6500, UV9300, UV9315, UV9430 (made by Momentive Performance Materials), X62-7622 (made by Shin-Etsu Chemical Co., Ltd.) etc. Can be mentioned. As a product commercially available as a radical polymerization type, X62-7205 (made by Shin-Etsu Chemical Co., Ltd.) etc. is mentioned, for example.

As the antistatic agent 3 contained in the releasing agent layer 2, it is preferable that dispersibility is favorable with respect to a silicone releasing agent solution, and that it does not inhibit hardening of a silicone releasing agent. Moreover, the antistatic agent 3 component contained in the releasing agent layer 2 is transferred to the surface of the adhesive layer 4 in contact with the releasing agent layer 2 to impart an antistatic function to the surface of the adhesive layer 4. In order to do this, an antistatic agent that does not react with the silicone-based release agent is preferable. As such an antistatic agent, an alkali metal salt is preferable.

As an alkali metal salt, the metal salt which consists of lithium, sodium, and potassium is mentioned. Specifically, for example, Li ^+, Na ^+, with a cation selected from ^{K +, Cl -, Br -} , I -, BF 4 -, PF 6 -, SCN -, ClO 4 -, CF 3 SO 3 _{^{-, (CF 3 SO 2)}} 2 N -, (C 2 F 5 SO 2) 2 N -, (CF 3 SO 2) 3 C - a metal salt consisting of an anion selected from is preferably used. Among them, LiBr, LiI, LiBF ₄ , LiPF ₆ , LiSCN, LiClO ₄ , LiCF ₃ SO ₃ , Li (CF ₃ SO ₂ ) ₂ N, Li (C ₂ F ₅ SO ₂ ) ₂ N, Li (CF ₃ SO ₂₎ is a lithium salt, such as ₃ C are preferably used. These alkali metal salts may be used alone, or may be used by mixing two or more kinds. In order to stabilize an ionic substance, you may add the compound containing a polyoxyalkylene structure.

The amount of the antistatic agent added to the silicone release agent varies depending on the type of the antistatic agent and the degree of affinity with the silicone release agent, but the desired peeling electrification voltage when peeling the surface protective film from the adherend, contamination to the adherend, and adhesive properties It may be set in consideration of the like. The mixing ratio (weight ratio) of the silicone-based peeling agent and the antistatic agent is, for example, preferably a ratio of 5 to 100 as the solid content of the solid content 100 of the silicone-based peeling agent, and the ratio of 5 to 60. More preferred. When the addition amount of the solid content conversion of the antistatic agent is less than the ratio of 5 with respect to the solid content 100 of the silicone-based peeling agent, the transfer amount of the antistatic agent to the surface of the pressure-sensitive adhesive layer also decreases, and the antistatic function is hardly exerted on the pressure-sensitive adhesive. Moreover, when the addition amount of solid content conversion of an antistatic agent exceeds 100 ratio with respect to solid content 100 of a silicone type peeling agent, since a silicone type peeling agent component is also transferred to the surface of an adhesive layer with antistatic agent, there exists a possibility that the adhesive characteristic of an adhesive may be reduced. .

The release agent layer 2 consists of at least a silicone type release agent and an antistatic agent which does not react with the release agent. The mixing method of a silicone type peeling agent and an antistatic agent is not specifically limited. Method of adding and mixing an antistatic agent to the silicone release agent and mixing, adding and mixing the catalyst for curing the release agent, dilution of the silicone release agent with an organic solvent in advance, and then adding and mixing the antistatic agent and the catalyst for curing the release agent, silicone release agent After dilution with an organic solvent in advance, any method, such as a method of adding and mixing a catalyst and then adding and mixing an antistatic agent, may be used. In addition, the peeling agent layer 2 is a material which assists antistatic effect, such as a adhesion improving agent, such as a silane coupling agent, a compound containing a polyoxyalkylene group, a printing agent, such as a cellulose compound, as needed, You may contain the material etc. which adjust a slipperiness | lubricacy.

What is necessary is just to form the release agent layer 2 in the surface of the base film 1 by a well-known method. Specifically, well-known coating methods, such as gravure coating, Mayer bar coating, and air knife coating, can be used.

In the adhesive layer 4 formed in the surface protection film 5 which concerns on this invention, the antistatic agent 3 component contained in the peeling agent layer 2 exists in the inside (other than the surface) of the adhesive layer 4. Instead, it exists only on the surface of the adhesive layer 4. For this reason, the time-dependent change of the peeling antistatic performance of the surface protection film 5 and the contamination to a to-be-adhered body can be suppressed.

The pressure-sensitive adhesive layer 4 formed on the surface protective film 5 according to the present invention is adhered to the surface of the adherend and can be easily peeled off after use, and the pressure-sensitive adhesive layer hardly contaminates the adherend. It is not specifically limited. Considering that the durability after bonding the surface protective film 5 which concerns on this invention to the optical film is calculated | required, etc., it is preferable that it is an acrylic adhesive layer formed by bridge | crosslinking a (meth) acrylate copolymer.

As a (meth) acrylate copolymer, Main monomers, such as n-butyl acrylate, 2-ethylhexyl acrylate, isooctyl acrylate, and isononyl acrylate, acrylonitrile, vinyl acetate, methyl methacrylate, ethyl A copolymer obtained by copolymerizing functional monomers such as comonomers such as acrylate, acrylic acid, methacrylic acid, hydroxyethyl acrylate, hydroxybutyl acrylate, glycidyl methacrylate and N-methylol methacrylamide Can be mentioned. As for the (meth) acrylate copolymer, all the main monomer and other monomers may be (meth) acrylate, and as monomers other than a main monomer, you may contain 1 type (s) or 2 or more types of monomers other than (meth) acrylate.

Moreover, you may copolymerize or mix the compound containing a polyoxyalkylene group in the (meth) acrylate copolymer. Examples of the compound containing a polyoxyalkylene group copolymerizable include polyethylene glycol (400) monoacrylate ester, polyethylene glycol (400) monomethacrylate ester, methoxy polyethylene glycol (400) acrylate, and methoxy polyethylene glycol (400). Methacrylate, polypropylene glycol (400) monoacrylate ester, polypropylene glycol (400) monomethacrylate ester, methoxy polypropylene glycol (400) acrylate, methoxy polypropylene glycol (400) methacrylate, and the like. Can be mentioned. By copolymerizing the monomer containing these polyoxyalkylene groups with the main monomer and functional monomer of the said (meth) acrylate copolymer, the adhesive which consists of a copolymer containing a polyoxyalkylene group can be obtained.

As a compound containing the polyoxyalkylene group which can be mixed with a (meth) acrylate copolymer, the (meth) acrylate copolymer containing a polyoxyalkylene group is preferable, and the (meth) acrylic type containing a polyoxyalkylene group The polymer of a monomer is more preferable, For example, polyethyleneglycol (400) monoacrylic acid ester, polyethyleneglycol (400) monomethacrylic acid ester, methoxy polyethyleneglycol (400) acrylate, methoxy polyethyleneglycol (400) meta Polymers, such as a acrylate, polypropylene glycol (400) monoacrylic acid ester, polypropylene glycol (400) monomethacrylic acid ester, methoxy polypropylene glycol (400) acrylate, and methoxy polypropylene glycol (400) methacrylate Can be mentioned. By mixing the compound containing these polyoxyalkylene groups with the said (meth) acrylate copolymer, the adhesive in which the compound containing a polyoxyalkylene group was added can be obtained.

As a hardening | curing agent added to the adhesive layer 4, an isocyanate compound, an epoxy compound, a melamine compound, a metal chelate compound, etc. are mentioned as a crosslinking agent which crosslinks a (meth) acrylate copolymer. Examples of the tackifier include rosin, coumarone indene, terpene, petroleum, phenol and the like.

Although the thickness of the adhesive layer 4 formed in the surface protection film 5 which concerns on this invention is not specifically limited, For example, the thickness of about 5-40 micrometers is preferable, and the thickness of about 10-30 micrometers is More preferred. The operability at the time of peeling a surface protection film from a to-be-adhered body is that it is the adhesive layer 4 which has a non-adhesive force with respect to the surface of the to-be-adhered body of a surface protection film being 0.03-0.3 N / 25 mm. It is preferable at the point which is excellent.

The method of forming the adhesive layer 4 in the base film 1 of the surface protection film 5 which concerns on this invention should just be performed by a well-known method, It does not specifically limit. Specifically, known coating methods such as reverse coating, comma coating, gravure coating, slot die coating, Meyer bar coating and air knife coating can be used.

In the surface protection film 5 which concerns on this invention which has the said structure, it is preferable that the surface potential at the time of peeling the adhesive layer 4 from the optical film which is a to-be-adhered body is +0.7 kPa--0.7 kPa. Moreover, it is more preferable that surface potentials are +0.5 kV--0.5 kV, and it is especially preferable that surface potentials are +0.2 kV--0.2 kV. This surface potential can be adjusted by adding or subtracting the kind, addition amount, etc. of the antistatic agent 3 contained in the peeling agent layer 2. What is necessary is just to adjust the kind and addition amount of the antistatic agent 3 of the releasing agent layer 2 in consideration of the surface contamination of the optical film which is a to-be-adhered body after peeling the surface protection film 5 from the optical film which is a to-be-adhered body.

FIG. 2 is a conceptual cross-sectional view showing a state in which the release agent layer 2 and the pressure-sensitive adhesive layer 4 are in contact with the surface protective film 5 of the present invention wound in a roll shape. Adhesive layer which does not contain antistatic agent 3 in the other surface of the base film 1, and is formed by the release agent layer 2 containing the antistatic agent 3 in one surface of the base film 1 When the surface protection film 5 in which the (4) is formed is made into the surface protection film 10 of the state wound up in roll shape with the adhesive layer 4 inside, the release agent layer 2 and the radial direction of a roll body are carried out. It will be in the state which the adhesive layer 4 contacted. For this reason, a part of the antistatic agent (symbol 3) component contained in the peeling agent layer 2 is transferred to the surface of the adhesive layer 4. 3 shows the state which bonded together the optical component 6 the surface protection film 5 unwound from the surface protection film 10 of the state wound by the roll shape obtained in this way. The antistatic agent 3 component is transferred from the release agent layer 2 to the surface of the pressure sensitive adhesive layer 4, thereby avoiding the surface protective film 5 in comparison with the pressure sensitive adhesive layer 4 before transferring the antistatic agent 3 component. After bonding to a complex, the peeling electrification voltage at the time of peeling the surface protection film 5 from a to-be-adhered body reduces. Here, the peeling electrification voltage at the time of peeling the surface protection film 5 of FIG. 1 from a to-be-adhered body can be measured by a well-known method. For example, after bonding the surface protection film 5 to adherends, such as a polarizing plate, a to-be-adhered body peels off the surface protection film 5 at a peeling speed of 40 m per minute using a high-speed peeling tester (Tester industry make). The maximum value of the absolute value of surface potential when the surface potential of the surface is measured every 10 ms using a surface electrometer (manufactured by Keyence Co., Ltd.) is measured as the peeling electrification voltage.

In the surface protection film 10 of the state wound by roll shape which concerns on this invention, when bonding the surface protection film 5 rewound from roll shape to a to-be-adhered body, the antistatic agent transferred to the surface of this adhesive layer 4 is carried out. (3) contacts the surface of the adherend. For this reason, the peeling electrification voltage at the time of peeling the surface protection film 5 from a to-be-adhered body can be restrained low. In addition, in the surface protection film 10 of the state wound by the roll shape which concerns on this invention, since the release agent layer 2 is the outer side and the adhesive layer 4 is inside, the surface of the adhesive layer 4 in a roll state is carried out. It is protected without exposure. Since the release agent layer 2 is integrated with the base film 1 even after rewinding the surface protection film 5 from a roll shape, the removal and disposal of the release agent layer 2 is unnecessary.

3 is a cross-sectional view showing an optical component 7 having a surface protective film formed thereon as one of the embodiments in which the surface protective film 5 of the present invention is bonded to the optical component. The optical component 7 in which the surface protection film was formed releases the surface protection film 5 of this invention from the surface protection film 10 of the state wound by roll shape, and is an adherend through the adhesive layer 4 It is obtained by bonding to the optical component 6. As the optical component 6, optical films, such as a polarizing plate, a retardation plate, a lens film, a polarizing plate combined with a retardation plate, and a polarizing plate combining a lens film, are mentioned. Such an optical component is used as a structural member of liquid crystal display devices, such as a liquid crystal display panel, and optical system devices of various instruments. Moreover, optical films, such as an antireflection film, a hard-coat film, and a transparent conductive film for touch panels, are mentioned as an optical component.

After unwinding from the surface protection film 10 of the state which wound the surface protection film 5 of this invention in roll shape, and bonding to the optical component (film for optics) which is a to-be-adhered body, the surface protection film 5 to a to-be-adhered body. When peeling off, the peeling electrification voltage can be suppressed low enough. For this reason, there is no possibility of destroying circuit components, such as a driver IC, a TFT element, and a gate line drive circuit, and can raise the production efficiency in the process of manufacturing a liquid crystal display panel, etc., and can maintain the reliability of a production process.

Example

Next, the present invention will be described in more detail with reference to Examples.

(Example 1)

(Production of surface protection film)

5 parts by weight of addition reaction type silicone (manufactured by Toray Dow Corning, Inc., SRX-345), 0.75 parts by weight of lithium bis (fluorosulfonyl) imide, 95 parts by weight of a 1: 1 mixed solvent of toluene and ethyl acetate And 0.05 weight part of platinum catalyst (Toray Dow Corning Co., Ltd. product name: SRX-212) were mixed, stirred, and mixed, and the coating material which forms the peeling agent layer of Example 1 was prepared.

On the other hand, 100 parts by weight of a 40% ethyl acetate solution of the pressure-sensitive adhesive consisting of a copolymer of 90 parts by weight of 2-ethylhexyl acrylate, 7 parts by weight of methoxy polyethylene glycol (400) methacrylate, and 3 parts by weight of 2-hydroxyethyl acrylate. 2 parts by weight of an isocyanate-based curing agent (Coronate® HX manufactured by Tosoh Corporation) was stirred and mixed to prepare an adhesive composition of Example 1.

On the surface of the polyethylene terephthalate film having a thickness of 38 µm, the paint forming the release agent layer of Example 1 was applied so that the thickness after drying was 0.2 µm, and dried in a hot air circulation oven at 120 ° C. for 1 minute. A release agent layer was formed. Next, after apply | coating the prepared adhesive composition so that the thickness after drying may be set to 20 micrometers on the surface where the release agent layer of a polyethylene terephthalate film is not formed, it dries for 2 minutes in 100 degreeC hot-air circulation type oven, and forms an adhesive layer. It was. Then, the release agent layer was formed in one surface of the obtained base film, and the adhesive layer was wound inside in roll shape so that a release agent layer and an adhesive layer might contact the film in which the adhesive layer was formed in the other surface. The pressure-sensitive adhesive film wound in the obtained roll shape was kept in an environment at 40 ° C for 5 days to cure the pressure-sensitive adhesive layer, thereby obtaining a surface protective film in the state of being wound in the roll shape of Example 1.

(Example 2)

Except having made thickness after drying of the coating material which forms the release agent layer of Example 1 into 0.1 micrometer, it carried out similarly to Example 1, and obtained the surface protection film of the state wound by the roll shape of Example 2.

(Example 3)

The addition reaction type silicone of Example 1 was manufactured by Toray Dow Corning Co., Ltd., product name: SRX-211, and substituted with lithium bis (trifluoromethanesulfonyl) imide instead of lithium bis (fluorosulfonyl) imide. Except the one, it carried out similarly to Example 1, and obtained the surface protection film of the state wound by the roll shape of Example 3.

(Comparative Example 1)

Except not adding lithium bis (fluorosulfonyl) imide which is an antistatic agent, it carried out similarly to Example 1, and obtained the surface protection film of the state wound by the roll shape of the comparative example 1.

(Comparative Example 2)

Instead of adding lithium bis (fluorosulfonyl) imide to the release agent, except for adding 0.67 parts by weight of lithium bis (fluorosulfonyl) imide to 100 parts by weight of 40% ethyl acetate solution on the pressure-sensitive adhesive side It carried out similarly to 1, and obtained the surface protection film of the state wound by the roll shape of the comparative example 2.

Hereinafter, it shows about the method and the result of an evaluation test.

<Measurement method of development force of surface protection film>

The sample of the surface protection film rewound from the surface protection film of the state wound by roll shape is cut | disconnected in the state which two layers overlapped, and is cut out in width 50mm and length 150mm. In the test environment of 23 ° C. × 50% RH, the strength at the time of peeling in the 180 ° direction at a peel rate of 300 mm / min using a tensile tester was measured, and this was determined as the development force (N / 50 mm) of the surface protective film. It was.

(Surface resistivity of release agent layer and pressure-sensitive adhesive layer)

The surface resistivity (Ω / □) of the release agent layer and the adhesive layer of the sample of the surface protection film rewound from the roll shape using a high-performance high resistivity meter (Hyrestar (registered trademark) -UP manufactured by Mitsubishi Chemical Analyzer Co., Ltd.), It measured on the conditions of 100 V of applied voltages and 30 second of measurement time.

<Measurement method of adhesive force of surface protection film>

The polarizing plate (AG-LR polarizing plate) which carried out the anti-glare low reflection process which bonded the acrylic film to the polarizer (polyvinyl alcohol film containing iodine) using the ultraviolet curable adhesive was made into an adherend. This polarizing plate was bonded together by the double-sided adhesive tape using the bonding machine on the surface of a glass plate. Then, after bonding the surface protection film cut | disconnected to width 25mm on the acrylic film of the polarizing plate surface, it stored for 1 day in 23 degreeC x 50% RH test environment. Then, the intensity | strength at the time of peeling a surface protection film in 180 degree direction at the peeling speed of 300 mm / min using a tensile tester was measured, and this was made into adhesive force (N / 25mm).

<Measurement method of peeling electrification voltage of surface protection film>

The polarizing plate (AG-LR polarizing plate) which carried out the anti-glare low reflection process which bonded the acrylic film to the polarizer (polyvinyl alcohol film containing iodine) using the ultraviolet curable adhesive was made into an adherend. This polarizing plate was bonded together by the double-sided adhesive tape using the bonding machine on the surface of a glass plate. Then, after bonding the surface protection film cut | disconnected to width 25mm on the acrylic film of the polarizing plate surface, it stored for 1 day in 23 degreeC x 50% RH test environment. Thereafter, the surface potential of the surface of the polarizing plate was measured every 10 ms using a surface electrometer (manufactured by Keyence Co., Ltd.) while the surface protective film was peeled off at a peel rate of 40 m per minute using a high speed peel tester (manufactured by Tester Industry). The maximum value of the absolute value of the surface potential at the time was made into peeling electrification voltage.

<Confirmation method of surface contamination of surface protection film>

The polarizing plate (AG-LR polarizing plate) which carried out the anti-glare low reflection process which bonded the acrylic film to the polarizer (polyvinyl alcohol film containing iodine) using the ultraviolet curable adhesive was made into an adherend. This polarizing plate was bonded together by the double-sided adhesive tape using the bonding machine on the surface of a glass plate. Then, after bonding the surface protection film cut | disconnected to width 25mm on the acrylic film of the polarizing plate surface, it stored for 3 days and 30 days in 23 degreeC x 50% RH test environment. Thereafter, the surface protective film was peeled off and the presence or absence of contamination on the surface of the polarizing plate was visually observed to confirm surface contamination. As a criterion for determining surface contamination, the case where no migration of contamination was made on the polarizing plate was set as (circle), and the case where contamination transfer was confirmed on the polarizing plate was set as (×).

Table 1 shows the measurement result measured about the surface protection film of the state wound in the roll shape of obtained Examples 1-3 and Comparative Examples 1-2. "2EHA" is 2-ethylhexyl acrylate, "HEA" is 2-hydroxyethyl acrylate, "# 400G" is methoxy polyethylene glycol (400) methacrylate, and "AS agent (1)" Lithium bis (fluorosulfonyl) imide, "AS agent (2)" is lithium bis (trifluoromethanesulfonyl) imide, "SRX-345" is SRX-345, "SRX-211" Is SRX-211, and "SRX212" means platinum catalyst SRX-212, respectively. In addition, "4.2E11" of surface resistivity means 4.2x10 <^11> , "overrange" means exceeding the measurement limit of a measuring instrument, and means 1.0x10 <^{13> (} ohm) / square or more.

From the measurement result shown in Table 1, the following is understood.

When the surface protection film of the state wound by the roll shape of Examples 1-3 which concerns on this invention rewinds from roll shape and uses, it has moderate adhesive force and there is no contamination with the surface of a to-be-adhered body. Moreover, even if a to-be-adhered body is a polarizing plate using an acrylic film, the peeling electrification voltage at the time of peeling off from a to-be-adhered body is low, after bonding a surface protection film to a to-be-adhered body once.

On the other hand, the surface protection film of the state wound in the roll shape of the comparative example 1 which did not add an antistatic agent to a peeling agent layer, after bonding the surface protection film rewound from roll shape to a to-be-adhered body once, when peeling off from a to-be-adhered body, Peeling electrification voltage became high. In addition, instead of containing an antistatic agent in a releasing agent layer, the surface protection film of the state wound up to the roll shape of the comparative example 2 which contained the antistatic agent in the adhesive layer once bonded the surface protection film rewound from the roll shape to the to-be-adhered body. Then, although the peeling electrification voltage at the time of peeling from a to-be-adhered body is favorable, the contamination with respect to the to-be-adhered body after peeling off a surface protection film increased.

That is, it is difficult for the surface protection film of the state wound in the roll shape of Comparative Examples 1-2 to make reduction of peeling electrification voltage and low pollution property to a to-be-adhered body. On the other hand, the surface protection film of the rolled-up state of Examples 1-3 which added the antistatic agent to the peeling agent layer, and transferred the antistatic agent component only to the surface of an adhesive layer, reduces the peeling electrification voltage and is low with respect to a to-be-adhered body. The compatibility of contaminants was good.

The surface protection film of this invention is a said optical film in production processes, such as optical films, such as a polarizing plate, a phase difference plate, a lens film, an antireflection film, a hard coat film, a transparent conductive film, and other various optical components, for example. It can be used to protect the surface by bonding to a surface such as a part. Moreover, after bonding the surface protection film of this invention to the optical component (optical film) which is a to-be-adhered body, the peeling electrification voltage which arises when peeling a surface protection film from a to-be-adhered body can be suppressed low, and also the peeling antistatic performance It is of great industrial value because it has little change over time and contamination of adherends and can improve the yield of production process.

One… Base film, 2... Release agent layer, 3... Antistatic agent, 4... Pressure-sensitive adhesive layer, 5... Surface protection film, 6... Optical component (optical film), 7... Optical part with surface protection film formed, 10... Surface protection film of the state wound in roll shape.

Claims (3)

A release agent layer is formed over the whole surface of one surface of the base film which consists of resin which has transparency,
As a surface protection film in which an adhesive layer is formed in the other surface of the said base film,
The pressure-sensitive adhesive layer is an acrylic pressure-sensitive adhesive layer containing a (meth) acrylate copolymer crosslinked,
The release agent layer contains an antistatic agent made of an alkali metal salt and a silicone release agent,
The antistatic agent component which consists of the said alkali metal salt contained in the said peeling agent layer exists only in the surface in the said adhesive layer,
The adhesive force with respect to the surface of the to-be-adhered body of the said surface protection film measured by the measuring method of the adhesive force of the following surface protection film is 0.03-0.3 N / 25mm,
The pressure-sensitive adhesive layer does not contain a metal chelate compound,
The surface resistivity of the said adhesive layer of the surface protection film rewound from roll shape is 3.7x10 <^{10> (} ohm) / (square) -6.5 * 10 <^{10> (} ohm) / (square), The surface protection film characterized by the above-mentioned:
-Measurement method of adhesive force of surface protection film: The said polarizing plate (AG-LR polarizing plate) which carried out the anti-glare low reflection process which bonded the acrylic film to the polarizer (polyvinyl alcohol film containing iodine) using an ultraviolet curable adhesive agent is adhered to the said Sieve, the polarizing plate was bonded to the surface of the glass plate with a double-sided adhesive tape using a bonding machine, and then bonded to the surface protective film cut to a width of 25 mm on the acrylic film on the surface of the polarizing plate, and then 23 It stored for 1 day in the test environment of ° C x 50% RH, and then measured the strength when the surface protective film was peeled off in the 180 ° direction at a peel rate of 300 mm / min using a tensile tester, and this was the adhesive force. It is set to (N / 25mm). The method of claim 1,
The said base film is wound in roll shape with the said adhesive layer inward so that the said peeling agent layer and the said adhesive layer may contact, The surface protection film characterized by the above-mentioned. The optical component of Claim 1 or 2 with which the surface protection film is bonded together through the said adhesive layer.

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