KR102364205B1 - surface protection film - Google Patents

Abstract

In the present invention, the thickness of the polyester-based substrate constituting the separator laminated on the optical surface protection film is specified, and by providing a cavity, the peeling force of the separator to the pressure-sensitive adhesive layer is suppressed, and the peelability and workability are improved. It is excellent and provides the surface protection film for optics provided with the separator which can suppress generation|occurrence|production of the dent resulting from a separator with the separator excellent in cushioning property by having a cavity. The optical surface protection film provided with the separator of the present invention includes an optical surface protection film having a pressure-sensitive adhesive layer on at least one side of a base film, and a side opposite to the side in contact with the pressure-sensitive adhesive layer of the base film, a separator having a separator It is an optical surface protection film provided, wherein the separator has a release layer and a polyester substrate, the polyester substrate has a cavity, the thickness of the polyester substrate is 25 to 100 μm, It is characterized in that the 180° gauge peel force for the pressure-sensitive adhesive layer is 0.7N/50mm or less.

Description

surface protection film

This invention relates to the surface protection film for optics provided with a separator. In particular, an adhesive layer constituting an optical surface protection film used for protecting the surface of an optical member (eg, a polarizing plate, a wave plate, a retardation plate, an optical compensation film, a reflective sheet, a brightness enhancing film, etc. used for a liquid crystal display) By sticking (laminated) the specific separator used in order to protect the surface until the time of actual use, it is excellent in peelability and workability|operativity, and generation|occurrence|production of a dent can be prevented, and it is useful.

A surface protection film generally has the structure in which the adhesive layer was provided on the film-form base film (support body). Such a surface protection film is bonded to an optical member as an adherend through the pressure-sensitive adhesive layer, and thereby is used for the purpose of protecting the optical member from scratches or contamination on the surface in the case of processing, conveying, inspection, and the like. For example, the panel of a liquid crystal display is formed by bonding optical members, such as a polarizing plate and a wave plate, to a liquid crystal cell through an adhesive layer. Until such an adhesive layer is actually affixed to an optical member, from the necessity of protecting from drying etc., the separator etc. by which the release process was carried out are protected, and are stored (patent document 1).

After that, when the pressure-sensitive adhesive layer surface of the surface protection film is actually affixed to the optical member and used, the separator is peeled off and removed.

Japanese Patent Laid-Open No. 2012-224811

In addition, when the separator is thick, peeling occurs, and when the peeling force (adhesive force) to the pressure-sensitive adhesive layer constituting the surface protection film of the separator when removed becomes high, a problem of poor peelability and workability arises.

In addition, when a thin separator is used instead of a thick separator for adhesive coating, the adhesive layer is caused by fine particles (for example, polyester-based fillers, etc.) included in the substrate constituting the separator attached to the surface of the separator. When formed, it causes dents on the surface of the pressure-sensitive adhesive layer. In addition, when bonding to an adherend in a state where the surface of the pressure-sensitive adhesive layer has dents, air bubbles enter the dented portion (space) between the pressure-sensitive adhesive layer and the adherend, resulting in a problem that deteriorates the inspection properties at the time of inspection of the adherend. do.

Then, in view of the above circumstances, as a result of earnest research, the present inventors specify the thickness of the polyester-based substrate constituting the separator laminated on the optical surface protection film, and further provide a cavity to determine the stiffness (rigidity) of the separator. By weakening the separator, the peeling force to the pressure-sensitive adhesive layer of the separator can be suppressed, and the peelability and workability are excellent. It aims at providing the surface protection film for optics provided with the separator which is excellent in test|inspection property.

That is, the optical surface protection film provided with the separator of the present invention includes an optical surface protection film having a pressure-sensitive adhesive layer on at least one side of the base film, and a side opposite to the side in contact with the base film of the pressure-sensitive adhesive layer, a separator It is an optical surface protection film provided with a separator having, wherein the separator has a release layer and a polyester base material, the polyester base material has a cavity, and the polyester base material has a thickness of 25 to 100 µm; , characterized in that the 180° gauge peel force of the separator to the pressure-sensitive adhesive layer is 0.7N/50mm or less.

It is preferable that the void ratio of the surface protection film for optics provided with the separator of this invention is 15 % or more with respect to the volume of the said polyester-type base material.

As for the surface protection film for optics provided with the separator of this invention, it is preferable that the said base film is a polyester film.

As for the surface protection film for optics provided with the separator of this invention, it is preferable that the said adhesive layer is formed from the adhesive composition containing a (meth)acrylic-type polymer.

The present invention specifies the thickness of the polyester-based substrate constituting the separator to be laminated on the optical surface protection film, and provides a cavity, thereby suppressing the peeling force of the separator to the pressure-sensitive adhesive layer constituting the optical surface protection film and excellent in peelability and workability, and by having a cavity, by a separator excellent in cushioning property, generation of dents due to the separator can be suppressed, and the optical surface protection film is bonded to the adherend It is useful because it is possible to obtain a surface protection film for optics provided with a separator excellent in inspection properties.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic sectional drawing which shows one structural example of the surface protection film for optics provided with the separator which concerns on this invention.
It is a schematic sectional drawing which shows one structural example at the time of peeling a separator from the surface protection film for optics provided with the separator which concerns on this invention.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described in detail.

<Entire structure of the surface protection film for optics provided with a separator>

The surface protection film for optics with a separator disclosed herein (hereinafter, simply referred to as "surface protection film") is generally referred to as an adhesive tape, an adhesive label, an adhesive film, or the like, on the surface of an adhesive layer. A surface protection that protects the surface of the optical component during processing, inspection, and transportation of an optical component (for example, an optical component used as a liquid crystal display panel component such as a polarizing plate or a wave plate), which is protected by this separator It is suitable as a film. Although the pressure-sensitive adhesive layer in the surface protection film is typically formed continuously, it is not limited to such a form, For example, the pressure-sensitive adhesive layer formed in a regular or random pattern such as dots or stripes may be used. In addition, a roll type may be sufficient as the surface protection film disclosed herein, and a sheet|flesh type may be sufficient as it.

<Base film>

The surface protection film for optics which comprises the surface protection film for optics provided with the separator of this invention has a base film, It is characterized by the above-mentioned. In the technology disclosed herein, the resin material constituting the base film can be used without particular limitation, but for example, it has excellent properties such as transparency, mechanical strength, thermal stability, moisture shielding property, isotropy, flexibility, and dimensional stability. It is preferable to use In particular, when a base film has flexibility, an adhesive composition can be apply|coated by a roll coater etc., can be wound up in roll shape, and is useful.

As said base film (support body), For example, Polyester-type polymers, such as a polyethylene terephthalate (PET), a polyethylene naphthalate (PEN), and a polybutylene terephthalate; Cellulose polymers, such as a diacetyl cellulose and a triacetyl cellulose; polycarbonate-based polymers; acrylic polymers such as polymethyl methacrylate; A plastic film composed of a resin material containing the same as the main resin component (the main component in the resin component, typically a component accounting for 50 wt% or more) can be preferably used as the base film. As another example of the said resin material, Styrene-type polymers, such as polystyrene and an acrylonitrile-styrene copolymer; olefinic polymers such as polyethylene, polypropylene, polyolefin having a cyclic or norbornene structure, and an ethylene-propylene copolymer; vinyl chloride-based polymers; amide-based polymers such as nylon 6, nylon 6, 6, and aromatic polyamide; What makes a resin material etc. is mentioned. As another example of the resin material, imide-based polymer, sulfone-based polymer, polyethersulfone-based polymer, polyetheretherketone-based polymer, polyphenylenesulfide-based polymer, vinyl alcohol-based polymer, vinylidene chloride-based polymer, vinyl buty A ral-type polymer, an arylate-type polymer, a polyoxymethylene-type polymer, an epoxy-type polymer, etc. are mentioned. The base film which consists of a blend of 2 or more types of the above-mentioned polymer may be sufficient.

As said base film, the plastic film which consists of a transparent thermoplastic resin material is employable preferably. It is a more preferable aspect to use a polyester film among the said plastic film. Here, the polyester film is mainly made of a polyester-based polymer material (polyester resin) having a main skeleton based on an ester bond such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polybutylene terephthalate. It means that it is made with a resin component. Such a polyester film has characteristics preferable as a base film of a surface protection film, such as being excellent in an optical characteristic and dimensional stability.

Various additives, such as antioxidant, a ultraviolet absorber, a plasticizer, and a coloring agent (pigment, dye, etc.), may be mix|blended with the resin material which comprises the said base film as needed. For example, known or customary surface treatment such as corona discharge treatment, plasma treatment, ultraviolet irradiation treatment, acid treatment, alkali treatment, and application of a primer may be applied. Such surface treatment may be, for example, a treatment for increasing the adhesion between the base film and the pressure-sensitive adhesive layer (the anchoring property of the pressure-sensitive adhesive layer).

As the base film, it is also possible to use a plastic film subjected to an antistatic treatment. By using the said base film, since charging of surface protection film itself at the time of peeling is suppressed, it is preferable. Moreover, the base film is a plastic film, and by giving an antistatic treatment to the said plastic film, the thing excellent in the antistatic ability with respect to a to-be-adhered body by reducing the electrification of the surface protection film itself is obtained. In addition, there is no restriction|limiting in particular as a method of providing an antistatic function, A conventionally well-known method can be used, For example, the antistatic resin which consists of an antistatic agent and a resin component, a conductive polymer, or a conductive resin containing a conductive substance. and a method of coating a conductive material, a method of depositing or plating a conductive material, and a method of mixing an antistatic agent or the like.

As thickness of the said base film, it is 5-200 micrometers normally, Preferably it is about 10-100 micrometers. When the thickness of the said base film exists in the said range, since it is excellent in the bonding workability|operativity with respect to a to-be-adhered body, and peelability and workability|operativity from a to-be-adhered body, it is preferable.

The surface protection film disclosed herein may be implemented in an embodiment including another layer in addition to the base film, the pressure-sensitive adhesive layer, and the separator. As said other layer, the undercoating layer (anchor layer) etc. which improve anchoring property of an antistatic layer and an adhesive layer are mentioned.

<Adhesive layer>

The pressure-sensitive adhesive layer used in the present invention can be used without any particular limitation, as long as it is formed of a pressure-sensitive adhesive composition containing a pressure-sensitive adhesive polymer having tackiness. As the pressure-sensitive adhesive composition, for example, an acrylic pressure-sensitive adhesive, a urethane-based pressure-sensitive adhesive, a synthetic rubber-based pressure-sensitive adhesive, a natural rubber-based pressure-sensitive adhesive, a silicone pressure-sensitive adhesive, a polyester-based pressure-sensitive adhesive, etc. can be used, among them, an acrylic pressure-sensitive adhesive, a urethane pressure-sensitive adhesive, and a group consisting of a silicone pressure-sensitive adhesive It is preferable to use (contain) at least one selected from among, and it is a particularly preferable aspect to use a pressure-sensitive adhesive composition (acrylic pressure-sensitive adhesive) containing the (meth)acrylic polymer as the pressure-sensitive adhesive polymer.

When the pressure-sensitive adhesive layer uses an acrylic pressure-sensitive adhesive, the (meth)acrylic polymer, which is a pressure-sensitive adhesive polymer constituting the acrylic pressure-sensitive adhesive, is a raw material monomer constituting this, a (meth)acrylic monomer having an alkyl group having 1 to 14 carbon atoms. It can be used as a monomer. As said (meth)acrylic-type monomer, 1 type(s) or 2 or more types can be used. By using the (meth)acrylic monomer having an alkyl group having 1 to 14 carbon atoms, it is easy to control the peeling force (adhesive force) to the adherend (subject to be protected) to a low level, and a surface excellent in light peelability and re-peelability A protective film is obtained. In addition, the (meth)acrylic-type polymer in this invention means an acryl-type polymer and/or a methacrylic-type polymer, and (meth)acrylate means an acrylate and/or a methacrylate.

Specific examples of the (meth)acrylic monomer having an alkyl group having 1 to 14 carbon atoms include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, s-butyl (meth) Acrylate, t-butyl (meth) acrylate, isobutyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) ) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, n-dodecyl (meth) acrylate, n- Tridecyl (meth)acrylate, n-tetradecyl (meth)acrylate, etc. are mentioned.

Especially, in the surface protection film of this invention, n-butyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, iso Octyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, n-dodecyl (meth) acrylate and (meth)acrylic monomers having an alkyl group having 4 to 14 carbon atoms, such as , n-tridecyl (meth)acrylate and n-tetradecyl (meth)acrylate. In particular, by using the (meth)acrylic monomer having an alkyl group having 4 to 14 carbon atoms, it becomes easy to control the peeling force (adhesive force) to the adherend to be low, and it becomes excellent in re-peelability.

In particular, it is preferable to contain 65 wt% or more of a (meth)acrylic monomer having an alkyl group having 1 to 14 carbon atoms with respect to 100 wt% of the total amount of the monomer component constituting the (meth)acrylic polymer, more preferably 75 % by weight or more, more preferably from 85 to 99.9% by weight, and most preferably from 90 to 99% by weight. When it will be less than 50 weight%, the moderate wettability of an adhesive composition and the cohesive force of an adhesive layer will fall, and it is unpreferable.

In addition, the said (meth)acrylic-type polymer can use a hydroxyl-group containing (meth)acrylic-type monomer as a raw material monomer. As said hydroxyl-group containing (meth)acrylic-type monomer, 1 type(s) or 2 or more types can be used. By using the hydroxyl group-containing (meth)acrylic monomer, it is easy to control crosslinking of the pressure-sensitive adhesive composition, etc. it gets easier

Examples of the hydroxyl group-containing (meth)acrylic monomer include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 6- Hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, (4-hydroxymethylcyclo Hexyl) methyl acrylate, N-methylol (meth)acrylamide, etc. are mentioned.

It is preferable to contain 25 wt% or less of the hydroxyl group-containing (meth)acrylic monomer with respect to 100 wt% of the total amount of monomer components constituting the (meth)acrylic polymer, more preferably 15 wt% or less, further Preferably it is 0.1 to 10 weight%. When it exists in the said range, since it becomes easy to control the balance of the wettability of an adhesive composition and the cohesion force of the adhesive layer obtained, it is preferable.

In addition, as another polymerizable monomer component, the Tg is set to 0°C or lower (usually -100°C or higher) for the reason that it is easy to balance the adhesive performance, and the glass transition temperature and peelability of the (meth)acrylic polymer are The polymerizable monomer for adjustment, etc. can be used in the range which does not impair the effect of this invention.

In addition, the said (meth)acrylic-type polymer can use a carboxyl group-containing (meth)acrylic-type monomer as a raw material monomer. By using the carboxyl group-containing (meth)acrylic monomer, it is possible to suppress an increase in the adhesive force over time of the pressure-sensitive adhesive layer (surface protection film), and it is excellent in re-peelability, adhesive strength increase prevention property, and workability. Moreover, it is excellent also in shear force with the cohesive force of an adhesive layer, and it is preferable.

As said carboxyl group-containing (meth)acrylic-type monomer, (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, etc. are mentioned, for example.

With respect to 100% by weight of the total amount of the monomer component constituting the (meth)acrylic polymer, the amount of the carboxyl group-containing (meth)acrylic monomer is preferably 10% by weight or less, more preferably 0 to 8% by weight, more preferably 0 to 6 It is more preferable that it is weight %. When it exists in the said range, since it becomes easy to control the balance of the wettability of an adhesive composition and the cohesion force of the adhesive layer obtained, it is preferable.

In addition, the said (meth)acrylic-type polymer can be used without specifically limiting, as long as it exists in the range which does not impair the characteristic of this invention other polymerizable monomers other than the said raw material monomer. For example, as the other polymerizable monomers, cohesive strength and heat resistance improving components such as cyano group-containing monomers, vinyl ester monomers, and aromatic vinyl monomers, amide group-containing monomers, imide group-containing monomers, amino group-containing monomers, and epoxy group-containing monomers , N-acryloylmorpholine, vinyl ether monomer, etc. can be suitably used components having a functional group acting as a starting point of crosslinking or improving peeling force (adhesive force). Especially, it is preferable to use nitrogen-containing monomers, such as a cyano group containing monomer, an amide group containing monomer, an imide group containing monomer, an amino group containing monomer, and N-acryloylmorpholine. The use of a nitrogen-containing monomer is useful because it is possible to ensure a suitable peeling force (adhesive force) that does not cause floatation, peeling, etc., and to obtain a surface protection film excellent in shearing force. These polymerizable monomers can use 1 type or 2 or more types.

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

Examples of the amide group-containing monomer include acrylamide, methacrylamide, diethylacrylamide, N-vinylpyrrolidone, N,N-dimethylacrylamide, N,N-dimethylmethacrylamide, N,N- Diethylacrylamide, N,N-diethylmethacrylamide, N,N'-methylenebisacrylamide, N,N-dimethylaminopropylacrylamide, N,N-dimethylaminopropylmethacrylamide, diacetoneacrylamide and the like.

As said imide group containing monomer, cyclohexyl maleimide, isopropyl maleimide, N-cyclohexyl maleimide, itaconimide etc. are mentioned, for example.

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

As said vinyl ester monomer, vinyl acetate, a vinyl propionate, a vinyl laurate, etc. are mentioned, for example.

As said aromatic vinyl monomer, styrene, chlorostyrene, chloromethylstyrene, (alpha)-methylstyrene, other substituted styrene, etc. are mentioned, for example.

As said epoxy-group containing monomer, glycidyl (meth)acrylate, methylglycidyl (meth)acrylate, allyl glycidyl ether, etc. are mentioned, for example.

As said vinyl ether monomer, methyl vinyl ether, ethyl vinyl ether, isobutyl vinyl ether, etc. are mentioned, for example.

In the present invention, the amount of the other polymerizable monomer is preferably 0 to 30% by weight, more preferably 0 to 10% by weight, based on 100% by weight of the total amount of the monomer component constituting the (meth)acrylic polymer. Do. The above other polymerizable monomers can be appropriately adjusted in order to obtain desired properties.

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

In addition, the average added mole number of oxyalkylene units of the alkylene oxide group-containing reactive monomer is preferably 1 to 40, more preferably 3 to 40, from the viewpoint of compatibility with the oxyalkylene group-containing compound, It is more preferable that it is 4-35, and it is especially preferable that it is 5-30. When the said average added mole number is 1 or more, there exists a tendency for the contamination reduction effect of to-be-adhered body (to-be-protected object) to be acquired efficiently. Moreover, when the said average added mole number is larger than 40, since interaction with an oxyalkylene group containing compound is large and the viscosity of an adhesive composition rises and there exists a tendency for coating to become difficult, it is unpreferable. In addition, the terminal of an oxyalkylene chain|strand may be substituted with a hydroxyl group as it is, another functional group, etc.

The alkylene oxide group-containing reactive monomer may be used alone or in combination of two or more, but the total content is preferably 0 to 20% by weight based on the total amount of the monomer component of the (meth)acrylic polymer. And, it is more preferable that it is 0 to 10 weight%. When the content of the alkylene oxide group-containing reactive monomer exceeds 20% by weight, the staining property to the adherend is deteriorated, so it is not preferable.

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

Moreover, it is more preferable that the said alkylene oxide group containing reactive monomer is a reactive monomer which has an ethylene oxide group. By using a reactive monomer-containing (meth)acrylic polymer having an ethylene oxide group as the base polymer, compatibility between the base polymer and the oxyalkylene group-containing compound is improved, bleed to an adherend is appropriately suppressed, and a low-staining adhesive A composition is obtained.

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

Specific examples of the (meth)acrylic acid alkylene oxide adduct include, for example, polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, polyethylene glycol-polypropylene glycol (meth) acrylate, polyethylene glycol-polybutyl Ren glycol (meth) acrylate, polypropylene glycol-polybutylene glycol (meth) acrylate, methoxy polyethylene glycol (meth) acrylate, ethoxy polyethylene glycol (meth) acrylate, butoxy polyethylene glycol (meth) acrylic Rate, octoxy polyethylene glycol (meth) acrylate, lauroxy polyethylene glycol (meth) acrylate, stearoxy polyethylene glycol (meth) acrylate, phenoxy polyethylene glycol (meth) acrylate, methoxy polypropylene glycol (meth) Acrylate, octoxy polyethylene glycol- polypropylene glycol (meth)acrylate, etc. are mentioned.

Moreover, as a specific example of the said reactive surfactant, an anionic reactive surfactant, nonionic reactive surfactant, cationic reactive surfactant etc. which have a (meth)acryloyl group or an allyl group are mentioned, for example.

The (meth)acrylic polymer preferably has a weight average molecular weight (Mw) of 100,000 to 5,000,000, more preferably 200,000 to 4,000,000, still more preferably 300,000 to 3,000,000, and most preferably 300,000 to 120 million. When a weight average molecular weight is smaller than 100,000, there exists a tendency to produce adhesive residue because the cohesive force of an adhesive layer becomes small. On the other hand, when the weight average molecular weight exceeds 5 million, the fluidity of the polymer decreases, the wetting to the adherend (eg, a polarizing plate) becomes insufficient, and swelling occurring between the adherend and the pressure-sensitive adhesive layer of the surface protection film tends to be the cause of In addition, a weight average molecular weight says what was obtained by measuring by GPC (gel permeation chromatography).

Moreover, as for the glass transition temperature (Tg) of the said (meth)acrylic-type polymer, 0 degreeC or less is preferable, More preferably, it is -10 degreeC or less (usually -100 degreeC or more). When the glass transition temperature is higher than 0 ° C., the polymer is difficult to flow, for example, the wetting to the polarizing plate, which is an optical member, becomes insufficient, and it tends to cause expansion occurring between the polarizing plate and the pressure-sensitive adhesive layer of the surface protection film. . In particular, the adhesive layer excellent in the wettability with respect to a polarizing plate and light-peelability becomes easy to be obtained by making a glass transition temperature into -70 degreeC or less. In addition, the glass transition temperature of a (meth)acrylic-type polymer can be adjusted within the said range by changing suitably the monomer component and composition ratio to be used.

The polymerization method of the (meth)acrylic polymer is not particularly limited, and polymerization can be performed by known methods such as solution polymerization, emulsion polymerization, bulk polymerization, and suspension polymerization. In view of properties such as low contamination with respect to a sieve), solution polymerization is a more preferable embodiment. In addition, any of a random copolymer, a block copolymer, an alternating copolymer, a graft copolymer, etc. may be sufficient as the polymer obtained.

<Oxyalkylene group-containing compound>

The pressure-sensitive adhesive composition used in the present invention can also contain an oxyalkylene group-containing compound. By containing the oxyalkylene group-containing compound, it is possible to further express light-peelability. As an oxyalkylene group containing compound, the organopolysiloxane which has an oxyalkylene chain|strand, and the oxyalkylene group containing compound which does not contain an organopolysiloxane are mentioned.

As a specific example of the organopolysiloxane which has the said oxyalkylene chain, it is a specific example of the organopolysiloxane which has an oxyalkylene chain in a main chain, For example, as a commercial item, a brand name is X-22-4952, X-22-4272, X -22-6266, KF-6004, KF-889 (above, manufactured by Shin-Etsu Chemical Co., Ltd.), BY16-201, SF8427 (above, manufactured by Toray Dow Corning), IM22 (manufactured by Asahi Kasei Barker), etc. there is. Moreover, as an organosiloxane which has an oxyalkylene chain in a side chain, as a commercial item, for example, trade name KF-351A, KF-352A, KF-353, KF-354L, KF-355A, KF-615A, KF-945, KF- 640, KF-642, KF-643, KF-6022, X-22-6191, X-22-4515, KF-6011, KF-6012, KF-6015, KF-6017, X-22-2516 (or higher, Shin-Etsu Chemical Co., Ltd.) SF8428, FZ-2162, SH3749, FZ-77, L-7001, FZ-2104, FZ-2110, L-7002, FZ-2122, FZ-2164, FZ-2203, FZ- 7001, SH8400, SH8700, SF8410, SF8422 (above, manufactured by Toray Dow Corning), TSF-4440, TSF-4441, TSF-4445, TSF-4450, TSF-4446, TSF-4452, TSF-4460 (Momentive Performance) Materials Corporation), BYK-333, BYK-307, BYK-377, BYK-UV3500, BYK-UV3570 (by Big Chemie Japan) etc. are mentioned. These compounds may be used independently and may mix and use 2 or more types.

Specific examples of the organopolysiloxane-free oxyalkylene group-containing compound include, for example, polyoxyalkylene alkylamine, polyoxyalkylenediamine, polyoxyalkylene fatty acid ester, polyoxyalkylene sorbitan fatty acid ester, poly Nonionic surfactants, such as oxyalkylene alkylphenyl ether, polyoxyalkylene alkyl ether, polyoxyalkylene alkyl allyl ether, and polyoxyalkylene alkylphenyl allyl ether; anionic surfactants such as polyoxyalkylene alkyl ether sulfate salts, polyoxyalkylene alkyl ether phosphoric acid ester salts, polyoxyalkylene alkyl phenyl ether sulfate salts, and polyoxyalkylene alkyl phenyl ether phosphoric acid ester salts; In addition, cationic surfactants and zwitterionic surfactants having polyoxyalkylene chains (polyalkylene oxide chains), polyether-based compounds having polyoxyalkylene chains (including derivatives thereof), polyoxy and acrylic compounds having an alkylene chain (and derivatives thereof are included), and the like. Moreover, you may mix|blend a polyoxyalkylene chain containing monomer as a polyoxyalkylene chain containing compound. These polyoxyalkylene chain containing compounds may be used independently and may be used in combination of 2 or more type.

Specific examples of the polyether-based compound (polyether component) having the polyoxyalkylene chain include a block copolymer of polypropylene glycol (PPG)-polyethylene glycol (PEG), a block copolymer of PPG-PEG-PPG, and PEG-PPG. -PEG block copolymer etc. are mentioned. As the derivative of the polyether-based compound having a polyoxyalkylene chain, a terminal etherified oxypropylene group-containing compound (PPG monoalkyl ether, PEG-PPG monoalkyl ether, etc.), a terminal acetylated oxypropylene group-containing compound (Terminal acetylated PPG etc.) etc. are mentioned.

Moreover, as a specific example of the acrylic compound which has the said polyoxyalkylene chain, the (meth)acrylate polymer which has an oxyalkylene group is mentioned. As said oxyalkylene group, 1-50 are preferable, as for the added mole number of an oxyalkylene unit, 2-30 are more preferable, 2-20 are still more preferable. In addition, the terminal of the said oxyalkylene chain|strand may be substituted by the hydroxyl group as it is, an alkyl group, a phenyl group, etc.

It is preferable that the (meth)acrylate polymer which has the said oxyalkylene group is a polymer containing (meth)acrylic-acid alkylene oxide as a monomer component, As a specific example of the said (meth)acrylic-acid alkylene oxide, ethylene glycol group containing As the (meth)acrylate, for example, methoxy-polyethylene glycol (meth)acrylate type such as methoxy-diethylene glycol (meth)acrylate and methoxy-triethylene glycol (meth)acrylate, ethoxy- Ethoxy-polyethylene glycol (meth) acrylate type such as diethylene glycol (meth) acrylate, ethoxy-triethylene glycol (meth) acrylate, butoxy-diethylene glycol (meth) acrylate, butoxy-tri Butoxy-polyethylene glycol (meth)acrylate type such as ethylene glycol (meth)acrylate, phenoxy-polyethylene such as phenoxy-diethylene glycol (meth)acrylate, and phenoxy-triethylene glycol (meth)acrylate Glycol (meth) acrylate type, 2-ethylhexyl-polyethylene glycol (meth) acrylate, nonylphenol-polyethylene glycol (meth) acrylate type, methoxy-polyethylene glycol (meth) acrylate, etc. A propylene glycol (meth)acrylate type|mold etc. are mentioned.

Moreover, as said monomer component, other monomer components other than the said (meth)acrylic-acid alkylene oxide can also be used. Specific examples of the other monomer component include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, isobutyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, n-nonyl (meth) acrylate, iso Nonyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, n-dodecyl (meth) acrylate, n-tridecyl (meth) acrylate, n-tetradecyl (meth) acrylate ) acrylates and/or methacrylates having an alkyl group having 1 to 14 carbon atoms such as acrylate.

In addition, as other monomer components other than the (meth)acrylic acid alkylene oxide, carboxyl group-containing (meth)acrylate, phosphoric acid group-containing (meth)acrylate, cyano group-containing (meth)acrylate, vinyl esters, aromatic vinyl compounds, Acid anhydride group-containing (meth)acrylate, hydroxyl group-containing (meth)acrylate, amide group-containing (meth)acrylate, amino group-containing (meth)acrylate, epoxy group-containing (meth)acrylate, N-acryloyl It is also possible to use morpholine, vinyl ethers, etc. suitably.

As a more preferable aspect, the polyoxyalkylene chain containing compound which does not contain the said organopolysiloxane is a compound which has a (poly) ethylene oxide chain in at least one part. By mix|blending the said (poly) ethylene oxide chain containing compound, compatibility with a base polymer improves, bleed to a to-be-adhered body is suppressed suitably, and the low-staining adhesive composition is obtained. Especially, when the block copolymer of PPG-PEG-PPG is used especially, the adhesive excellent in low stain|contamination property is obtained. As said polyethylene oxide chain containing compound, it is preferable that the weight of the (poly) ethylene oxide chain to the whole polyoxyalkylene chain containing compound which does not contain the said organopolysiloxane is 5 to 90 weight%, More preferably, 5 to 85% by weight, more preferably 5 to 80% by weight, and most preferably 5 to 75% by weight.

Moreover, as a commercial item of the polyoxyalkylene chain containing compound which does not contain the said organopolysiloxane, For example, Adeka Pluronic 17R-4, Adeka Pluronic 25R-2 (above, all made by ADEKA Corporation), Lateml PD-420, Latemul PD-420, Latemel PD-450, Emulgen 120 (manufactured by Kaos), Aquaron HS-10, KH-10, Neugen EA-87, EA-137, EA-157, EA- 167, EA-177 (above, Daiichi Kogyo Seyaku Co., Ltd. make) etc. are mentioned.

The content of the oxyalkylene group-containing compound is preferably 0.01 to 5.0 parts by weight, more preferably 0.02 to 100 parts by weight of the pressure-sensitive adhesive polymer (main polymer, for example, (meth)acrylic polymer) constituting the pressure-sensitive adhesive composition. to 2 parts by weight, more preferably 0.03 to 1.6 parts by weight, and most preferably 0.1 to 0.8 parts by weight. When it exists in the said range, it becomes easy to express the light peelability (re-peelability) of the adhesive layer (surface protection film) used by this invention, and it is preferable.

<crosslinking agent>

As for the surface protection film of this invention, it is preferable that the said adhesive composition contains a crosslinking agent. Moreover, in this invention, it can be set as an adhesive layer using the said adhesive composition. For example, when the pressure-sensitive adhesive composition is an acrylic pressure-sensitive adhesive containing the (meth)acrylic polymer, crosslinking by appropriately adjusting the structural units, constituent ratios, selection and addition ratio of the crosslinking agent, etc. of the (meth)acrylic polymer, An adhesive layer (surface protection film) which is further excellent in heat resistance can be obtained.

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

As said isocyanate compound, For example, aliphatic polyisocyanates, such as trimethylene diisocyanate, butylene diisocyanate, hexamethylene diisocyanate (HDI), dimer acid diisocyanate, cyclopentylene diisocyanate, cyclohexylene diisocyanate, isophorone diisocyanate (IPDI), alicyclic isocyanates such as 1,3-bis(isocyanatomethyl)cyclohexane, 2,4-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate (XDI) Aromatic isocyanates, such as, modified by the said isocyanate compound by an allophanate bond, a biuret bond, an isocyanurate bond, a uretdione bond, a urea bond, a carbodiimide bond, a uretonimine bond, an oxadiazinetrione bond, etc. and modified polyisocyanates. For example, as a commercial item, Takenate 300S, Takenate 500, Takenate 600, Takenate D165N, Takenate D178N (above, Takeda Yakuhin Kogyo Co., Ltd. make), Sumidul T80, Sumidul L, Death module N3400 (above , Sumica Bayer Urethane Co., Ltd.), Milionate MR, Myllionate MT, Coronate L, Coronate HL, Coronate HX (above, manufactured by Nippon Polyurethane Kogyo Co., Ltd.), etc. are mentioned. These isocyanate compounds may be used individually, may be used in mixture of 2 or more types, and it is also possible to use them in combination with a bifunctional isocyanate compound and a trifunctional or more than trifunctional isocyanate compound. By using together and using a crosslinking agent, it becomes possible to make adhesiveness and repulsion resistance (adhesiveness with respect to a curved surface) compatible, and the adhesive layer (surface protection film) which is further excellent in adhesive reliability can be obtained.

Examples of the epoxy compound include N,N,N',N'-tetraglycidyl-m-xylenediamine (trade name TETRAD-X, manufactured by Mitsubishi Gas Chemicals) and 1,3-bis(N,N-) Diglycidylaminomethyl) cyclohexane (trade name: TETRAD-C, the Mitsubishi Gas Chemical company make) etc. are mentioned.

Hexamethylolmelamine etc. are mentioned as said melamine-type resin. As an aziridine derivative, the brand name HDU, TAZM, TAZO (above, the Sogo Corporation make) etc. as a commercial item are mentioned, for example.

As said metal chelate compound, aluminum, iron, tin, titanium, nickel etc. as a metal component, acetylene, methyl acetoacetate, ethyl lactate, etc. are mentioned as a chelate component.

The content of the crosslinking agent used in the present invention is, for example, with respect to 100 parts by weight of the (meth)acrylic polymer, preferably 0.01 to 20 parts by weight, more preferably 0.1 to 15 parts by weight, and 0.5 to 10 parts by weight. More preferably, 1 to 8 parts by weight is most preferable. When the content is less than 0.01 parts by weight, crosslinking formation by the crosslinking agent becomes insufficient, the cohesive force of the pressure-sensitive adhesive layer obtained becomes small, and sufficient heat resistance may not be obtained. On the other hand, when the content exceeds 20 parts by weight, the cohesive force of the polymer is large, the fluidity is lowered, the wetting to the adherend (eg, a polarizing plate) becomes insufficient, and between the adherend and the pressure-sensitive adhesive layer (pressure-sensitive adhesive composition layer) It tends to cause the swelling that occurs. In addition, these crosslinking agents may be used independently and may mix and use 2 or more types.

<Cross-linking catalyst>

The pressure-sensitive adhesive composition may further contain a crosslinking catalyst for further effectively advancing any of the crosslinking reactions described above. As such a crosslinking catalyst, for example, a tin-based catalyst such as dibutyltin dilaurate and dioctyltin dilaurate, tris(acetylacetonato)iron, tris(hexane-2,4-dionato)iron, tris(heptane- 2,4-Dionato)iron, tris(heptane-3,5-dionato)iron, tris(5-methylhexane-2,4-dionato)iron, tris(octane-2,4-dionato)iron , tris(6-methylheptane-2,4-dionato)iron, tris(2,6-dimethylheptane-3,5-dionato)iron, tris(nonane-2,4-dionato)iron, tris( Nonane-4,6-dionato)iron, tris(2,2,6,6-tetramethylheptane-3,5-dionato)iron, tris(tridecane-6,8-dionato)iron, tris( 1-phenylbutane-1,3-dionato)iron, tris(hexafluoroacetylacetonato)iron, tris(ethyl acetoacetate)iron, tris(acetoacetate-n-propyl)iron, tris(isopropyl acetoacetate) ) iron, tris(acetoacetate-n-butyl)iron, tris(acetoacetate-sec-butyl)iron, tris(acetoacetate-tert-butyl)iron, tris(propionylmethylacetate)iron, tris(propionylacetic acid) ethyl)iron, tris(propionylacetate-n-propyl)iron, tris(propionylisopropylacetate)iron, tris(propionylacetate-n-butyl)iron, tris(propionylacetate-sec-butyl)iron, Tris(propionylacetate-tert-butyl)iron, tris(benzylacetate)iron, tris(dimethyl malonate)iron, tris(diethylmalonate)iron, trimethoxyiron, triethoxyiron, triisopropoxy An iron-based catalyst such as iron or ferric chloride may be used. The number of these crosslinking catalysts may be one, and they may use 2 or more types together.

Although the content of the crosslinking catalyst is not particularly limited, for example, it is preferably about 0.0001 to 1 part by weight, more preferably 0.001 to 0.5 part by weight, based on 100 parts by weight of the (meth)acrylic polymer. When it exists in the said range, when an adhesive layer is formed, the speed|rate of a crosslinking reaction is quick, the pot life of an adhesive composition also becomes long, and it becomes a preferable aspect.

Further, the pressure-sensitive adhesive composition may contain other known additives, for example, lubricants, colorants, powders such as pigments, plasticizers, tackifiers, low molecular weight polymers, surface lubricants, leveling agents, antioxidants, corrosion inhibitors , a light stabilizer, an ultraviolet absorber, a polymerization inhibitor, a silane coupling agent, an antistatic agent, an inorganic or organic filler, a metal powder, a particulate or thin material, and the like can be appropriately added depending on the intended use.

<Surface protection film for optics provided with a separator>

The optical surface protection film (surface protection film) provided with the separator of the present invention is formed by forming the pressure-sensitive adhesive layer on at least one side of the base film. , it is also possible to transfer the pressure-sensitive adhesive layer made of the pressure-sensitive adhesive composition after crosslinking to a base film or the like.

In addition, the method of forming the pressure-sensitive adhesive layer on the base film is not particularly limited, but for example, the pressure-sensitive adhesive composition (solution) is applied to the base film, and the polymerization solvent is dried and removed to form the pressure-sensitive adhesive layer on the base film. do. Then, you may cure for the purpose of adjustment of the component migration of an adhesive layer, adjustment of a crosslinking reaction, etc. In addition, when the pressure-sensitive adhesive composition is applied on the base film to produce a surface protection film, one or more solvents other than the polymerization solvent may be newly added to the pressure-sensitive adhesive composition so as to be uniformly applied on the base film.

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

The surface protection film of this invention is usually 3-100 micrometers in thickness of the said adhesive layer, Preferably it is produced so that it may become about 5-50 micrometers. When the thickness of an adhesive layer exists in the said range, since it will be easy to obtain the suitable balance of re-peelability and adhesiveness, it is preferable.

Moreover, it is preferable that the total thickness of the surface protection film of this invention is 8-300 micrometers, It is more preferable that it is 10-200 micrometers, It is most preferable that it is 20-100 micrometers. If it is in the said range, it is excellent in adhesive characteristics (re-peelability, adhesiveness, etc.), workability|operativity, and an external appearance characteristic, and it becomes a preferable aspect. In addition, the said total thickness means the sum total of thickness including all layers, such as a base film, an adhesive layer, a separator, and another layer.

<Separator>

The surface protection film of the present invention has a pressure-sensitive adhesive layer on at least one side of a base film, and a separator on the opposite side to the side in contact with the base film of the pressure-sensitive adhesive layer, wherein the separator is a release layer and a polyester base material is characterized in that the polyester-based substrate has a cavity, the polyester-based substrate has a thickness of 25 to 100 μm, and the 180° gauge peel force of the separator to the pressure-sensitive adhesive layer is 0.7 N/50 mm or less. do it with The separator is to bond the separator to the surface of the pressure-sensitive adhesive layer for the purpose of protecting the pressure-sensitive adhesive surface of the pressure-sensitive adhesive layer, and in particular, by having a specific thickness and cavity, the stiffness (rigidity) of the separator itself can be suppressed low, and the pressure-sensitive adhesive layer It is excellent in peelability and workability at the time of peeling a separator from the surface, and cushioning property by a cavity can be provided, adhesive dent etc. which may occur after adhesive coating can be prevented, and it becomes a preferable aspect.

<Polyester base material>

The polyester-based substrate (which may be simply referred to as a “substrate”) is not particularly limited as long as it is a polyester film that can protect the pressure-sensitive adhesive layer and has voids, for example, polyethylene terephthalate film, polyethylene A naphthalate film, a polybutylene terephthalate film, etc. are mentioned.

The polyester-based substrate has a thickness of 25 to 100 μm, preferably 30 to 80 μm, and more preferably 40 to 70 μm. When it exists in the said range, since it is excellent in the bonding workability|operativity with respect to an adhesive layer, and the peelability and workability|operativity with respect to an adhesive layer, it is preferable. Moreover, when the thickness of a base material exceeds 100 micrometers, stiffness (rigidity) of separator itself becomes strong, peelability and workability|operativity are inferior, and it is unpreferable.

If necessary, the surface of the polyester-based substrate may be subjected to various surface treatments such as corona discharge treatment or may be subjected to various surface treatments such as embossing. Further, if necessary, various additives such as fillers (inorganic fillers, organic fillers, etc.), antioxidants, antioxidants, ultraviolet absorbers, antistatic agents, lubricants, plasticizers, colorants (pigments, dyes, etc.) may be blended.

With respect to the volume of the polyester-based substrate, the porosity is preferably 15% (vol%) or more, more preferably 18% or more, and still more preferably 20% or more. When the porosity is 15% or more, the cushioning property of the separator is improved, and the filler (eg, polyethylene terephthalate (PET)) contained in the base film constituting the optical surface protection film or the polyester base material constituting the separator. The unevenness|corrugation resulting from filler) can be absorbed, and generation|occurrence|production of adhesive dents etc. resulting from a separator etc. can be suppressed. Moreover, since stiffness (rigidity) of a separator becomes low, the peelability of a separator improves. Moreover, from a viewpoint of the intensity|strength of a separator, etc., as a void ratio, it is preferable that it is 40 % or less, and 30 % or less is more preferable.

As a shape of the cavity of the said polyester-based base material, it is a spherical shape, an elliptical spherical shape, a thread shape, etc., and it is preferable to take a dispersed form. 0.01-100 micrometers is preferable and, as for the said dispersion diameter, it is more preferable that it is 0.05-30 micrometers. If it exists in the said range, since there exists the intensity|strength of a separator, it is excellent in cushioning property, and it is excellent in the peelability of a separator, it becomes a preferable aspect. Moreover, the shape of the said cavity can be observed from the cross section of a base material with a scanning electron microscope.

<Release layer>

The release layer may have adhesion to the polyester-based substrate, and may have releasability to the pressure-sensitive adhesive layer, and may be formed of a release agent composition. Although it does not restrict|limit especially as said mold release agent composition, For example, silicone compounds, such as dimethylsiloxane and diphenylsiloxane, silicone resin, fluororesin, Long-chain alkyl compounds, such as acioresin, etc. can be used.

In addition, the release agent composition may contain other known additives, for example, antistatic agents, colorants, powders such as pigments, surfactants, plasticizers, tackifiers, low molecular weight polymers, surface lubricants, leveling agents, Antioxidant, corrosion inhibitor, light stabilizer, ultraviolet absorber, polymerization inhibitor, silane coupling agent, inorganic or organic filler, metal powder, particulate form, etc. can be added suitably according to the use used.

<Production of Separator>

The said separator is formed using the said mold release agent composition on the said polyester-based base material.

The method of forming the release layer on the polyester-based substrate is not particularly limited, but for example, a solution of the release agent composition is applied to the substrate, and the polymerization solvent is dried and removed to form the release layer on the substrate. . Then, you may cure for the purpose of adjustment etc. of component migration of a release layer. In addition, when the mold release agent composition is applied on the base material to prepare the release layer, one or more solvents other than the polymerization solvent may be newly added to the release agent composition so that the release agent composition can be uniformly applied on the base material.

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

The thickness of the said release layer is 1-200 nm typically, Preferably it is 5-100 nm, More preferably, it is 10-50 nm. When the thickness of a mold release layer is too thin, the mold release effect by a mold release layer will be weak, and it will become difficult to peel a separator, For this reason, the operation|work to bond the surface protection film for optics may become difficult. On the other hand, when too thick, the contamination property of the adhesive layer of the surface protection film for optics may be affected.

As a commercial item of the above separator, for example, CRISPA K7211-50 μm, CRISPA K7211-38 μm (above, manufactured by Toyobo), PET50 (K2411) PAT1 8LK, PET50 (K2411) PAT 19K (above, manufactured by Lintec), etc. can be heard

<Bonding of optical surface protection film and separator>

The surface protection film for optics provided with the separator of this invention is an aspect formed by bonding the release layer of the said separator to the adhesive layer surface of the said surface protection film for optics. A well-known method is used for joining.

<Optical member>

In this invention, the optical member can be protected by sticking to the optical member the surface protection film for optics which peeled the said separator from the surface of the adhesive layer of the said surface protection film for optics provided with the said separator. Since the separator has excellent cushioning properties, dents are unlikely to occur, and peelability is also good, and since the optical surface protection film is excellent in appearance quality (appearance), it protects the surface during processing, conveyance, shipment, etc. Since it can be used for a use (surface protection film), in order to protect the surface of the said optical member (polarizing plate etc.), it becomes useful.

Example

Hereinafter, some Examples related to the present invention will be described, but it is not intended to limit the present invention to those shown in these specific examples. In addition, "part" and "%" in the following description are based on weight unless there is particular notice. In addition, the compounding quantity (addition amount) in a table|surface was shown.

In addition, each characteristic in the following description was measured or evaluated as follows, respectively.

<Measurement of the porosity of the polyester-based substrate constituting the separator>

After photographing the cross section of the polyester-based substrate with a scanning electron microscope, the voids in the cross-sectional area are traced on a tracing film, and the painted picture is image-processed with an image analysis apparatus, and the void ratio (%) is the area ratio. It was calculated|required as , and this value was expressed as void percentage (volume %) as it is.

· Scanning electron microscope used: S-510 type scanning electron microscope manufactured by Hitachi Seisakusho.

・Image analysis processing device used: Luxex IID manufactured by Nireko Corporation

<Measurement of separator thickness>

The thickness of the separator (separator thickness) was the total thickness of the polyester base material and the mold release layer, and was measured using R1-205 manufactured by Ozaki Corporation.

<Measurement of (meth)acrylic polymer glass transition temperature (Tg)>

The glass transition temperature (Tg) (°C) was determined by the following formula using the following literature values as the glass transition temperature Tgn (°C) of the homopolymer of each monomer.

Formula: 1/(Tg+273)=Σ[Wn/(Tgn+273)]

(wherein, Tg(°C) is the glass transition temperature of the copolymer, Wn(−) is the weight fraction of each monomer, Tgn(°C) is the glass transition temperature of the homopolymer by each monomer, and n is the type of each monomer indicate.)

Literature value:

2-ethylhexyl acrylate (2EHA): -70°C

Butyl acrylate (BA): -55°C

2-hydroxyethyl acrylate (HEA): -15°C

Acrylic acid (AA): 106°C

In addition, "synthesis and design of acrylic resin and development of new uses" (published by the Central Management Development Center Publishing Department) was referred as a literature value.

<Measurement of weight average molecular weight (Mw) of (meth)acrylic polymer>

The weight average molecular weight (Mw) of the (meth)acrylic polymer to be used was measured using the Tosoh Corporation GPC apparatus (HLC-8220GPC). Measurement conditions are as follows.

Sample concentration: 0.2% by weight (THF solution)

Sample injection volume: 10 μl

Eluent: THF

Flow rate: 0.6ml/min

Measuring temperature: 40℃

column:

sample column; TSKguardcolumn SuperHZ-H (1 pc.) + TSKgel SuperHZM-H (2 pc.)

reference column; TSKgel SuperH-RC (1 pc.)

Detector: Differential Refractometer (RI)

In addition, the weight average molecular weight was calculated|required by polystyrene conversion value.

<Presence or absence of dents on the surface of the pressure-sensitive adhesive layer>

Under a dark room fluorescent lamp, the separator was peeled from the adhesive layer surface of the surface protection film for optics, light was reflected on the adhesive layer surface, and it confirmed visually whether there was no dent. The case where there was no dent was denoted as ○, and the case where there was dent was denoted as ×.

<Measurement of the instrument peeling force of the separator>

As shown in Fig. 2, a separator-equipped optical surface protection film 3 is cut to a size of 50 mm in width and 100 mm in length, and double-sided tape 4 (manufactured by Nitto Denko Corporation, No. 500) is bonded. The surface of the base film 22 constituting the optical surface protection film 3 provided with a separator on one glass 5 (S9213, manufactured by Matsunami Glass Kogyo Co., Ltd.) was subjected to a pressure of 0.25 MPa, 0.3 m/min. pressed at speed.

Then, the single-sided adhesive tape 6 (No. 720, the Nitto Denko company make, width 50mm) was cut to the length of 50 mm. The adhesive side of this single-sided adhesive tape 6 was crimped|bonded with the hand roller on the separator 1 of width 50mm of the surface protection film 3 for optics provided with a separator so that an edge part may protrude by 1 mm. This was left to stand for 10 second under the conditions of 23 degreeC and 50 %RH. Then, the maximum stress applied at the beginning of peeling when the single-sided adhesive tape 6 was peeled at the speed|rate of 0.3 m/min in a 180 degree direction with an autograph was made into instrument peeling force (N/50mm).

The gauge peeling force (pickup force) is 0.7N/50mm or less, preferably 0.68N/50mm or less, and more preferably 0.65N/50mm or less. If the instrument peeling force exceeds 0.7 N/50 mm, when a thick separator is used, it takes time to peel the separator from the surface of the pressure-sensitive adhesive layer of the optical surface protection film, and the peelability and workability are poor. not. On the other hand, since there exists a possibility that it may become impossible to fully protect the adhesive layer surface of the surface protection film for optics when instrument peeling force is too low, it is preferable that it is 0.2N/50mm or more.

<Preparation of (meth)acrylic polymer (A)>

100 parts by weight of 2-ethylhexyl acrylate (2EHA), 4 parts by weight of 2-hydroxyethyl acrylate (HEA), 2 as a polymerization initiator in a 4-neck flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a cooler , 0.2 parts by weight of 2'-azobisisobutyronitrile (AIBN) and 205 parts by weight of ethyl acetate were added, nitrogen gas was introduced while gently stirring, and the liquid temperature in the flask was maintained at around 63° C. for about 4 hours polymerization reaction was performed to prepare a (meth)acrylic polymer (A) solution (about 35% by weight). The weight average molecular weight of the said (meth)acrylic-type polymer (A) was 650,000, and Tg was -68 degreeC.

<Preparation of (meth)acrylic polymer (B)>

In a 4-neck flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a cooler, 95 parts by weight of butyl acrylate (BA), 5 parts by weight of acrylic acid (AA), and 2,2'-azobisisobutyro as a polymerization initiator 0.1 parts by weight of nitrile and 234 parts by weight of ethyl acetate were added, nitrogen gas was introduced while gently stirring, the liquid temperature in the flask was maintained at around 65 ° C., and polymerization reaction was performed for 6 hours, (meth) acrylic polymer (B) solution ( 30% by weight) was prepared. The weight average molecular weight (Mw) of the said (meth)acrylic-type polymer (B) was 1.1 million, and the glass transition temperature (Tg) was -47 degreeC.

[Preparation of acrylic adhesive (1) solution]

The (meth)acrylic polymer (A) solution (35% by weight) was diluted to 29% by weight with ethyl acetate, and 500 parts by weight of this solution (100 parts by weight of solid content) was added to hexamethylenedi, a trifunctional isocyanate compound, as a crosslinking agent. Isocyanurate form of isocyanate (Coronate HX: C/HX, manufactured by Nippon Polyurethane) 4 parts by weight (solid content 4 parts by weight), dibutyltin dilaurate as a crosslinking catalyst (“Sn” in Table 2, 1% by weight) Ethyl acetate solution) 1.5 weight part (0.015 weight part of solid content) was added, it kept at 25 degreeC vicinity, mixed and stirred for about 1 minute, and the acrylic adhesive (1) solution was prepared.

[Preparation of acrylic adhesive (2) solution]

The (meth)acrylic polymer (B) solution (30% by weight) was diluted to 29% by weight with ethyl acetate, and to 500 parts by weight (100 parts by weight of solid content) of this solution, an epoxy-based crosslinking agent (1,3- Bis(N,N-diglycidylaminomethyl)cyclohexane, epoxy equivalent: 110, number of functional groups: 4, trade name “TETRAD-C”: T/C, manufactured by Mitsubishi Gas Chemical Company) 6 parts by weight (solid content 6 weight) part) was added, mixing and stirring were performed, and the acrylic adhesive (2) solution was prepared.

[Preparation of acrylic adhesive (3) solution]

The (meth)acrylic polymer (A) solution (35% by weight) is diluted to 29% by weight with ethyl acetate, and to 500 parts by weight of this solution (100 parts by weight of solid content) as a crosslinking agent, an isocyanate-based crosslinking agent (hexamethylene diisocyanate) of isocyanurate (trade name "Coronate HX": C/HX, manufactured by Nippon Polyurethane) 5 parts by weight (solid content: 5 parts by weight), dibutyltin dilaurate (1% by weight ethyl acetate solution) as a crosslinking catalyst 3 Add 0.3 parts by weight (solid content: 0.03 parts by weight), polyoxyalkylene chain-containing compound that does not contain an additive organopolysiloxane (Aquaron HS-10, manufactured by Daiichi Kogyo Seyaku Co., Ltd.) 0.3 parts by weight (solid content: 0.3 parts by weight), and mix It stirred and prepared the acrylic adhesive (3) solution.

<Example 1>

[Production of antistatic treatment film]

An antistatic agent solution was prepared by diluting 10 parts by weight of an antistatic agent (manufactured by Solvex, Microsolver RMd-142, tin oxide and polyester resin as main components) with a mixed solvent consisting of 30 parts by weight of water and 70 parts by weight of methanol.

The obtained antistatic agent solution was applied on a polyethylene terephthalate (PET) film (thickness: 38 µm) as a base film using a Mayer bar, dried at 130 ° C. for 1 minute to remove the solvent, and an antistatic layer (thickness: 0.2 µm) was formed to produce an antistatic treatment film.

[Preparation of a surface protection film for optics with a separator]

The said acrylic adhesive (1) solution was apply|coated to the surface opposite to the antistatic treatment surface of the said antistatic treatment film, and it heated at 130 degreeC for 2 minutes, and formed the 15-micrometer-thick adhesive layer. Next, CRISPA K7211-50 μm, a separator that has been silicone-treated on one side of the surface of the pressure-sensitive adhesive layer (manufactured by Toyobo, the specific gravity of the polyester substrate: 1.1 g/cm 3 , the porosity of the polyester substrate: 20%, It bonded using the silicone-treated surface of 50 micrometers in thickness, and produced the surface protection film for optics provided with the separator.

<Examples 2 to 5, Comparative Examples 1 to 4>

As shown in Table 2, the acrylic pressure-sensitive adhesive (1) solution used in Example 1 or, instead, the acrylic pressure-sensitive adhesive (2) solution or the acrylic pressure-sensitive adhesive (3) solution was used, and the separator described in Table 3 was used. was the method similar to Example 1, and produced the surface protection film for optics provided with the separator.

About the surface protection film for optics provided with the separator which concerns on an Example and a comparative example, the result of having performed the compounding content mentioned above, various measurement, and evaluation was shown to Tables 1-3. In addition, the compounding quantity in a table|surface shows an active ingredient.

From Table 3 above, it can be confirmed that, in all examples, the porosity and thickness of the polyester-based substrate constituting the separator are within the desired range, so that the peelability and workability are excellent, and the occurrence of dents can also be prevented. could In addition, in the Example, since no dents occurred on the surface of the pressure-sensitive adhesive layer, there was no air bubble entering when bonding to the adherend, and at the time of inspection in a state in which the optical surface protection film was bonded to the adherend, It is possible to provide an optical surface protection film having excellent inspection properties. On the other hand, in Comparative Examples to 3, since the porosity of the polyester-based substrate constituting the separator is not included in the desired range, the stiffness (rigidity) of the separator is strong, and the peelability and workability are poor, and in Comparative Example 4, Since the thickness of a polyester base material was not contained in the desired range, cushioning property could not be expressed, but generation|occurrence|production of the dent resulting from a separator was confirmed.

The surface protection film for optics with a separator disclosed herein is a liquid crystal display panel, a plasma display panel (PDP), an organic electroluminescent (EL) display, etc. at the time of manufacture and conveyance of an optical member used as a component It is suitable as a surface protection film for protecting the said optical member etc. In particular, it is useful as a surface protection film for optics applied to optical members such as a polarizing plate (polarizing film) for a liquid crystal display panel, a wave plate, a retardation plate, an optical compensation film, a brightness improving film, a light diffusing sheet, and a reflective sheet.

1: separator
2: Optical surface protection film
3: Optical surface protection film provided with a separator
4: Double-sided adhesive tape
5: Glass
6: single-sided adhesive tape
11: polyester base material
12: release layer
21: adhesive layer
22: base film

Claims (4)

An optical surface protection film having an adhesive layer on at least one side of a base film, and a surface protection film for optics provided with a separator having a separator on the surface opposite to the surface of the pressure-sensitive adhesive layer in contact with the base film,
The separator has a polyester-based substrate and a release layer bonded to the pressure-sensitive adhesive layer,
The polyester-based substrate has a cavity,
The thickness of the polyester-based substrate is 25 to 100㎛,
An optical surface protection film with a separator, characterized in that the 180° gauge peeling force of the separator to the pressure-sensitive adhesive layer is 0.7N/50mm or less. The optical surface protection film with a separator according to claim 1, wherein the porosity is 15% or more with respect to the volume of the polyester-based substrate. The optical surface protection film with a separator according to claim 1, wherein the base film is a polyester film. The optical surface protection film with a separator according to any one of claims 1 to 3, wherein the pressure-sensitive adhesive layer is formed of a pressure-sensitive adhesive composition containing a (meth)acrylic polymer.

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