JPH09300541A - Surface protecting film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a surface protecting film excellent in ultraviolet cutting off properties and thermal laminating properties by providing a coating layer based on an ultraviolet absorbing acrylic resin and a thermal adhesive resin on the surface of a plastic film. SOLUTION: This surface protecting film is obtained by providing a coating layer based on an ultraviolet absorbing acrylic resin and a thermal adhesive resin on one surface of a plastic film. As the plastic film, a polyolefine film, a polystyrene film or a composite of them is used. The layer based on the ultraviolet absorbing acrylic resin and the thermal adhesive resin is 50% by wt. of the coating layer or more. The ultraviolet absorbing acrylic resin is a copolymer resin of a reactive benzophenone compd. having ultraviolet absorbing capacity or a reactive benzotriazole compd. and an acrylic monomer having a polymerizable unsaturated group.

Description

Detailed Description of the Invention

[0001]

[0001] The present invention relates to a surface protection film. Specifically, the present invention relates to a surface protective film having excellent durability and heat laminating property.

[0002]

2. Description of the Related Art Plastic films have been widely used as surface protection films for various substrates by taking advantage of their characteristics. Among them, the surface protective film provided with a thermoadhesive resin layer on the surface of the film is excellent in productivity because adhesion can be achieved in a very short time, and is also widely known as an economically effective surface protective material. There is. However, depending on such a surface protective film, when applied to the outdoors or the like, the heat-adhesive layer is required to have an ultraviolet blocking property in order to prevent the heat-adhesive layer and the material to be protected from deterioration or discoloration due to ultraviolet rays. Further, the surface protection film is required to be easily and firmly adhered to various base materials and have excellent durability.

Therefore, as a surface protective film having such a function, a heat-adhesive resin layer containing various ultraviolet absorbers on the surface of a base film, for example, ethylene-ethyl acrylate resin, ethylene-vinyl acetate A surface protective film formed by extruding a polymer resin, a polyester copolymer resin or the like by a laminating method or a coating method is known.

[0004]

However, in the conventional surface protective film, it is difficult to combine the heat-adhesive resin and the ultraviolet absorber, and if it is erroneous, the coating layer may become clouded due to poor compatibility, There is a defect that sufficient durability cannot be obtained because the ultraviolet absorber deposits on the surface layer and scatters over time. Further, since increasing the concentration of the ultraviolet absorber in the heat-adhesive resin is likely to induce deterioration of uniform dispersibility and deterioration of transparency and heat-adhesiveness, the coating layer itself may be required to obtain sufficient UV-blocking property. Need to thicken.

[0005] The present invention solves the above problems,
It is an object of the present invention to provide a surface protective film which has excellent ultraviolet shielding properties of the surface protective film and also has excellent thermal laminating properties.

[0006]

The surface protection film of the present invention for this purpose is provided with a coating layer containing an ultraviolet absorbing acrylic resin and a heat adhesive resin as main components on at least one surface of a plastic film. It consists of

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The plastic film used in the present invention may be of any kind as long as it is a plastic film. Typical examples are polyolefin film, polystyrene film, polyester film, polycarbonate film, Triacetyl cellulose film, cellophane film, fluorine film, polyamide film, polyimide film, polyphenylene sulfide film, polyetherimide film, polyether sulfone film, polysulfone film, polyacrylonitrile film, polyvinyl acetate film, polyether ether ketone film, etc. A single substance or a complex can be used.

However, it is preferable to use a polyester film, a polypropylene film, a polyphenylene sulfide film, or a fluorine film alone or in combination from the viewpoint of mechanical properties, thermal properties, etc. Among them, fluorine is excellent in weather resistance and antifouling property. Films are particularly preferred.

The material of the fluororesin film is not particularly limited, and various kinds can be used. Typical examples are tetrafluoroethylene polymer, ethylene-4fluoroethylene copolymer, tetrafluoroethylene-6fluoropropylene copolymer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, and 2 fluoropolymer. Vinylidene chloride polymer, 3
A fluorinated ethylene polymer, a fluorinated ethylene polymer, a chlorotrifluoroethylene polymer, or the like, or a copolymer or a mixture thereof can be used. However, mechanical properties, film formability,
From the viewpoint of processability, it is preferable to use a tetrafluoroethylene-6-fluoropropylene copolymer or an ethylene-4fluoroethylene copolymer, among which an ethylene-4fluoroethylene copolymer is the main component. Is particularly preferable. In addition, the main component means a substance which is 50% or more in the resin component, more preferably 70% or more, and may appropriately contain other substances. The resin to be added is not particularly limited, and for example, a polyolefin resin, an acrylic resin, or the like can be used.

If necessary, the plastic film may contain suitable additives such as a heat stabilizer, an oxidation stabilizer, a weather stabilizer, an ultraviolet absorber, a pigment, in an amount that does not impair the effects of the present invention. Dyes, inorganic or organic fine particles, dispersants, coupling agents, fillers and the like may be added. Further, the plastic film may be used in any of unoriented, uniaxially oriented and biaxially oriented, but the oriented film is desirable when mechanical strength is required.

The thickness of the plastic film is not particularly limited, and an appropriate thickness can be set within the range of about 1 to 500 μm according to the desired characteristics. Further, the surface roughness and optical characteristics of the plastic film are not particularly limited, and may be appropriately set to desired values in consideration of required characteristics.

Further, in the present invention, the surface treatment or undercoating treatment of the surface of the plastic film improves the adhesion to the coating layer, the water resistance, the solvent resistance and the like, so that it can be more preferably used. As the surface treatment, for example, corona discharge treatment (in air, nitrogen, carbon gas, etc.), plasma treatment (high pressure, low pressure), alkali metal solution treatment, high frequency sputter etching treatment, etc. can be performed.

In the case of surface treatment, the treatment strength is not particularly limited and may be a desired value. As a measure of treatment strength, the surface leak index of the film measured according to JIS-K-6768. Is preferably 35 dyn / cm or more, and more preferably 40 dyn / cm or more.

The coating layer of the present invention is a layer containing an ultraviolet absorbing acrylic resin and a heat adhesive resin as main components. The layer containing the main component refers to a layer that itself is 50% by weight or more in the coating layer, and other substances may be added as appropriate. In the present invention, such a coating layer is provided on at least one surface of the film support.

In the present invention, the ultraviolet absorbing acrylic resin is a copolymer resin of a reactive benzophenone compound or a reactive benzotriazole compound having an ultraviolet absorbing ability and an acrylic monomer having a polymerizable unsaturated group. Is.

The reactive benzophenone-based compound or benzotriazole-based compound is a monomer having an unsaturated group capable of being copolymerized in the molecule, and examples of the reactive benzophenone-based compound include 2- Hydroxy-4-methacryloxybenzophenone, 2-
Hydroxy-4- (2-hydroxy-3-methacryloxy) propoxybenzophenone, 2-hydroxy-4
-(2-methacryloxy) ethoxybenzophenone,
2-hydroxy-4-vinyloxycarbonylmethoxybenzophenone and the like can be mentioned, and examples of the reactive benzotriazole-based compound include 2- (2'-hydroxy-
3'-tert-butyl-5'-methylphenyl) -5-
(2 "-methacryloyloxyethyl) benzotriazole, 2 (2'-hydroxy-5'-methylphenyl)
-5- (2 "-methacryloyloxyethyl) benzotriazole, 2- (2'-hydroxy-5'-methacryloxyethylphenyl) -2H-benzotriazole, 2- (2'-hydroxy-5'-methacryloxyethyl) Phenyl) -5-chloro-2H-benzotriazole and the like.

The acrylic monomer is a basic formula

Embedded image (R: hydrogen or methyl group, R'is an alkyl group having 1 to 18 carbon atoms), alkyl acrylate, alkyl methacrylate, acrylic acid, methacrylic acid, β-
Hydroxy acrylate, β-hydroxy methacrylate, β-hydroxypropyl acrylate, β-hydroxypropyl methacrylate, polyoxyethylene glycol monomethacrylate, polyethylene polytetramethylene ether glycol monomethacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, acrylamide, methacrylamide,
N-methylmethacrylamide, Nn-butoxymethylacrylamide, acid phosphooxyethyl methacrylate, 3-chloro-2-acid phosphooxypropyl methacrylate, 3-chloro-2-hydroxypropyl methacrylate, glycidyl acrylate, glycidyl methacrylate, tetrahydroflur Furyl acrylate, tetrahydrofurfuryl methacrylate, methoxy polyethylene glycol monomethacrylate, 3-acrylamido-2-methylpropane sulfonic acid, N-methylol acrylamide, N-methylol methacrylamide, polyoxyethylene glycol dimethacrylate,
1,3-butylene glycol dimethacrylate, 1,6
At least one selected from hexanediol dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, dibromoneopentyl glycol dimethacrylate, tetramethylolmethane triacrylate and the like. Among them, alkyl methacrylate and alkyl acrylate are preferable in terms of their polymerizability and coating film characteristics, and examples thereof include methyl methacrylate and ethyl acrylate. Further, it is preferable to use a carboxyl group- or methylol group-containing acrylic monomer in terms of adhesion to the substrate.

In terms of the composition of the ultraviolet absorbing acrylic resin, 2-hydroxy-4-methacryloxybenzophenone or 2-hydroxy-4- (2-methacryloxy) ethoxybenzophenone is used as the reactive benzophenone compound. As the benzotriazole compound, 2- (2'-hydroxy-5'-methacryloxyethylphenyl) -2H-benzotriazole or 2- (2'-hydroxy-5'-methacryloxyethylphenyl) -5-chloro-2H- Those having a combination of benzotriazole and methyl methacrylate as an acrylic monomer as a main component are preferable in terms of characteristics. Also,
When the acrylic monomer is contained in an amount of 20% by weight or more and 80% by weight or less, transparency and coating film characteristics are excellent, which is more preferable.

In the present invention, the ultraviolet absorbing acrylic resin preferably has a glass transition temperature (Tg1) of 30 to 90 ° C., and one having a glass transition temperature (Tg1) of 40 to 80 ° C. is easy to handle and has compatibility with a heat adhesive resin. It is more preferable in terms of heat adhesion.

The ultraviolet absorbing acrylic resin can be used as an aqueous dispersion or an organic solvent, but in the case of an organic solvent, the organic solvent is, for example, a well-known alcohol-based, carboxylic ester-based, ketone-based, or fat-based resin. Examples thereof include group hydrocarbons, alicyclic or aromatic hydrocarbons, and mixtures thereof, and it is preferable to select those which do not adversely affect the coating property and the like.

The term "thermoadhesive resin layer" as used in the present invention means a thermoplastic resin, a mixture thereof, or a resin to which a low molecular weight paraffin or the like is added, which is melted by heating and solidified by cooling. A layer composed of a resin, specifically, for example, ethylene and an ethylene-vinyl acetate copolymer resin as a copolymer thereof, an ethylene-acrylate copolymer resin or an ionomer resin, vinyl acetate and a copolymer resin thereof, a polyamide Examples of the resin include a polyester resin, a polypropylene resin, a polypropylene resin, a polyurethane resin, a vinyl chloride resin, a polymethacrylic resin, and a polyester urethane resin. Among them, in the present invention, the polyester resin and the polyester urethane resin are included. It is more preferable to use a vinyl chloride resin or a polymethacrylic resin. Here, as the polyester resin,
Preference is given to those obtained by co-condensing various components based on terephthalic acid-based polyester.

As the vinyl chloride resin, in addition to vinyl chloride alone resin, a monomer copolymerizable with vinyl chloride, for example, vinyl acetate, ethylene, propylene, acrylic acid ester, methacrylic acid ester or the like is 40% by weight or less. And a resin compatible with 100 parts by weight of the above-mentioned resin, for example, ethylene-vinyl acetate copolymer resin, vinyl chloride-vinyl acetate copolymer resin and the like.
Examples thereof include resins mixed in an amount of 0 parts by weight or less.

The polymethacrylic resin is a resin mainly composed of polymethylmethacrylate, which is (1) polymethylmethacrylate homopolymer, or (2) methacrylic acid or methacrylic acid and a fatty acid having 2 to 8 carbon atoms. A copolymer of methyl methacrylate with one or more kinds of monomers selected from an ester of a group alcohol or an acrylic acid or an ester of an acrylic acid and an aliphatic alcohol having a carbon number of 1 to 8 and methyl methacrylate being 60 mol. % Or more, preferably 85 mol% or more, or 50% by weight, preferably 25% by weight, of the copolymer of (3), (1) and (2).
Examples thereof include those mixed within the following range. Specific examples thereof include homopolymers of methacrylic acid methyl ester or copolymers thereof with acrylic acid, methacrylic acid, or ethyl esters, butyl esters, isopropyl esters of acrylic acid, methacrylic acid, and the like.

In the present invention, the heat-adhesive resin preferably has a glass transition temperature (Tg2) of 0 to 50 ° C, preferably 5 to 40 ° C.
Those in the range are particularly preferable in terms of compatibility with the ultraviolet absorbing acrylic resin, thermal adhesiveness and the like.

In the present invention, the coating layer has a laminated thickness of 1 to 20.
The thickness is preferably 0 μm, and is preferably in the range of 5 to 100 μm from the viewpoints of uniform formation of the coating layer and adhesion after laminating. Further, in the coating layer, if necessary, various additives such as antifoaming agents, coatability improvers, thickeners, plasticizers, stabilizers, flame retardants, dyes in amounts that do not impair the effects of the present invention. Etc. may be included.

Further, in the present invention, the glass transition temperature (Tg of the ultraviolet absorbing acrylic resin constituting the coating layer is
1) and the glass transition temperature (Tg2) of the heat-adhesive resin are T
It is desirable that the relationship of g1> Tg2 is satisfied in terms of transparency and blocking resistance of the coating layer.

Furthermore, in the present invention, the weight mixing ratio (A / B) of the ultraviolet absorbing acrylic resin (A) and the heat adhesive resin (B) in the coating layer is 5/95 to 80 /.
20 is preferable, and those in the range of 30/70 to 70/30 are more preferable, and if it is out of this range, the handling property, thermal adhesiveness and the like are likely to deteriorate.

In the present invention, the adhesion of the coating layer, solvent resistance,
The coating layer is preferably cross-linked in order to further improve the heat resistance. A crosslinking agent is preferably used for crosslinking.

The cross-linking agent as used in the present invention means a functional group present in an ultraviolet absorbing acrylic resin or a heat-adhesive resin,
For example, a cross-linking agent that cross-links with a hydroxyl group, a carboxyl group, a glycidyl group, an amide group, and the like to finally form a coating layer having a three-dimensional network structure. As a typical example, a methylolated or alkylolated urea is used. Examples thereof include resins, melamine resins, acrylamide resins, polyamide resins, epoxy compounds, isocyanate compounds, aziridine compounds, and the like. In the present invention, among these, it is preferable to apply an isocyanate compound in terms of adhesion to the film support, crosslinkability, and the like.

These cross-linking agents may be used alone or in combination of two or more depending on the case. The amount of the cross-linking agent to be added is appropriately selected depending on the kind of the cross-linking agent, but is usually preferably 0.01 to 50 parts by weight, more preferably 0.2 to 30 parts by weight, based on 100 parts by weight of the resin solid content. . Further, it is more preferable to use a crosslinking catalyst together with the crosslinking binder because crosslinking will proceed further. As the crosslinking catalyst, salts, inorganic substances, organic substances, acid substances, alkaline substances and the like can be used. The amount of the crosslinking catalyst added is preferably 0.001 to 10 parts by weight, more preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the resin solid matter. The coating agent containing the additive is crosslinked by heating, ultraviolet rays, electron beams, etc. after coating on the support.
Usually, the method of heating is common.

In the present invention, for example, when workability is deteriorated due to insufficient adhesion or slippage during laminating of the surface protective film of the present invention with another type of substrate, inorganic or organic fine particles are added to the coating layer. It is desirable to include it.

Here, as the inorganic particles, for example, zinc carbonate, zinc oxide, zinc sulfide, talc, carion, weight / light weight or synthetic calcium carbonate, titanium oxide, silica,
Colloidal silica, lithium fluoride, calcium fluoride, barium sulfate, alumina, alumina sol, zirconia, calcium phosphate, natural or synthetic swelling or non-swelling mica, etc. can be used, and as the organic particles, for example, polystyrene, poly Methylstyrene, polymethoxystyrene, polyvinyl chloride, polyethylene, polypropylene, polyvinylidene chloride, polymethacrylate, polymethylmethacrylate, polychloroacrylate, styrene-divinylbenzene copolymer, melamine resin, epoxy resin, phenol resin, fluororesin, etc. Can be used, and at least one selected from these can be used.
Although more than one species can be used, it is not particularly limited. Further, the fine particles may be in a hollow porous state or a non-hollow porous state. Further, the fine particles may be subjected to a treatment such as adding a functional group such as a glycidyl group or a methylol group to the surface thereof in order to improve the dispersibility in the resin.

The average particle diameter of the fine particles is 0.01 to 500 μm.
Are preferable, and those in the range of 0.1 to 50 μm are more preferable from the viewpoint of handleability, coatability and the like. The content of the fine particles in the layer is preferably 0.1 to 50% by weight,
5% by weight is more preferred. If the content is outside this range, workability is likely to be deteriorated and the adhesion of the laminated product is likely to be deteriorated.

Next, a method for producing the film of the present invention will be described, but the invention is not limited to such an example.

First, as a method of forming a coating layer by a coating method, a method in which a solution, which is adjusted to a predetermined amount in advance, is applied to a film serving as a substrate in a film forming step, and then dried,
A method of providing a coating-drying step after winding the base film as a single film can be preferably applied.

The coating method is not particularly limited, and a melt coating method or the like may be used, but a gravure coating method, a reverse coating method, a kiss coating method, a die coating method, a meta coating method, because a thin film can be coated at a high speed. The ring bar coating method is preferred. The coating material concentration and the coating film drying conditions are not particularly limited, but it is desirable that the coating film drying conditions be performed within a range that does not adversely affect various properties of the coating layer and the base film. Next, as a method of forming a coating layer by extrusion laminating method, resin pellets are supplied to an extruder and melted at a temperature above the melting temperature and below the temperature at which the resin decomposes to form on the base film surface to a predetermined lamination thickness. The method etc. can be applied preferably.

[0037]

[Method of measuring and evaluating characteristics] The characteristic value of the present invention is as follows.
According to the following measurement methods and evaluation criteria.

(1) Thermal Laminating Property A coating layer of a surface protective film and a clean galvanized steel sheet (manufactured by Toyo Steel Sheet Co., Ltd.) having a thickness of 0.5 mm preheated at 160 ° C. are overlaid and the temperature is controlled by a laminator machine. 180
After thermocompression bonding at ℃, peel speed 200 with a Shopper tester
The adhesive force per 25 mm width was determined at mm / min and a peeling angle of 180 °.

(2) Ultraviolet ray blocking property After irradiating the coating layer surface for 300 hours using a Ubucon tester (manufactured by Toyo Seiki Seisakusho, Ltd.), Hitachi 340
Using a type broadband self-recording spectrophotometer (manufactured by Hitachi, Ltd.), the spectral spectrum in the wavelength range of 300 to 400 nm was measured and judged as follows.

◯: Good (light transmittance of 20 in the wavelength range of 300 to 350 nm is 20)
%) Less: somewhat inferior (light transmittance in the wavelength range of 300 to 350 nm is 20% or more and less than 50%) x: inferior (light transmittance in the wavelength range of 300 to 350 nm is 50)
%that's all)

(3) Blocking property Surface protective films are laminated (coating layer / base material layer) 23
The blocking property after 24 hours at a temperature of 65 RH% and a load of 500 g / 12 cm ² was determined based on the following.

◯: Good (no blocking occurred) Δ: Slightly inferior (some blocking occurred) ×: Poor (blocking occurred remarkably)

(4) Durability The coating layer surface was irradiated for 300 hours using a Ubucon tester (manufactured by Toyo Seiki Seisakusho Co., Ltd.), and then cellophane tape (manufactured by Nichiban Co., Ltd.) was pressed onto the coating layer. The cellophane tape was forcibly peeled in the direction of 180 ° and the degree of peeling between the layers was observed, and the judgment was made as follows.

◎: Very good (no peeling) ○: Good (peeling area less than 5%) △: Slightly inferior (peeling area 5% or more and less than 20%) ×: Poor (peeling area 20% or more)

(5) Glass transition temperature Differential scanning calorimeter (DSC manufactured by PERKIN-ELMER)
-2 type).

[0046]

The present invention will be described with reference to the following examples and comparative examples, but the present invention is not limited to these examples.

Examples 1 and 2 Fluororesin film "TOYOFLON" ET having a thickness of 60 μm
One side of FE (manufactured by Toray Industries, Inc.) (Example 1) and a polyester resin film “Lumirror” T60 (manufactured by Toray Industries, Inc.) having a thickness of 50 μm (Example 2) was subjected to corona discharge treatment in air, and the surface Methyl ethyl ketone / methyl isobutyl ketone (mixing ratio 1: 1) was used as a diluting solvent, and an ultraviolet absorbing acrylic resin ULS-9 having a glass transition temperature of 72 ° C. was added thereto.
35LH (produced by Yatasha Yushi Kogyo Co., Ltd.) and polyester thermal adhesive resin "Vylon" 500 having a glass transition temperature of 4 ° C.
(Toyobo Co., Ltd.) was mixed at a solid content weight ratio of 50:50, and a uniform coating material having a concentration of 15% by weight was applied.
It was dried at 0 ° C. for 2 minutes to obtain a surface protective film having a coating layer with a thickness of 8 μm. As shown in Table 1, the surface protection film was excellent in each property.

Example 3 In the coating material of Example 1, the isocyanate compound "coronate" was used as a cross-linking agent for the resin solid content of the coating material.
A surface protective film was obtained in the same manner as in Example 1 except that 10 parts by weight of HX (manufactured by Nippon Polyurethane Industry Co., Ltd.) was added. As shown in Table 1, the surface protective film was excellent in each property.

Examples 4 and 5 Based on Example 1, as a coating material, an ultraviolet absorbing acrylic resin ULS-935LH having a glass transition temperature of 53 ° C. and a polyester urethane thermal adhesive resin “Vylon” having a glass transition temperature of 23 ° C. UR8200 (manufactured by Toyobo Co., Ltd.) and solid content weight ratio of 10:90 (Example 4) and 70:30.
(Example 5), and the isocyanate-based cross-linking agent "Sumijour" N-75 was added to the resin solid content.
A surface protective film was obtained in the same manner as in Example 1 except that 5 parts by weight of (Sumitomo Bayer Co., Ltd.) was added to make the concentration 15% by weight. As shown in Table 1, the surface protection film was excellent in each characteristic.

Example 6 Based on Example 1, the ultraviolet absorbing acrylic resin used in Example 4 and the polyester thermoadhesive resin "Vylon" 600 having a glass transition temperature of 46 ° C. were mixed in a solid content weight ratio of 60:
A surface protective film was obtained in the same manner as in Example 1 except that the coating material was mixed with 40 and the crosslinking agent used in Example 4 was added in the same manner to give a concentration of 20% by weight. The characteristics of the surface protection film were excellent as shown in Table 1.

Comparative Examples 1 and 2 Based on Example 1, the heat-adhesive resin used in Example 1 and the benzophenone-based ultraviolet absorber "SEESORB" 101 were used.
(Manufactured by Cypro Kasei Co., Ltd.) (Comparative Example 1) and benzotriazole-based ultraviolet absorber "SEESORB" 701 (manufactured by Cypro Kasei Co., Ltd.) (Comparative Example 2) were used in a solid content weight ratio of 8
A coating material with a concentration of 15% by weight mixed at 0:20 was used in Example 1
A surface protective film applied in the same manner as in (1) was obtained. The characteristics of the obtained surface protection film are shown in Table 1. It can be seen that the blocking property is particularly poor.

Comparative Example 3 Based on Example 1, as a heat-adhesive resin, a polyester-based heat-adhesive resin “Vylon” 20 having a glass transition temperature of 67 ° C.
0 and benzotriazole-based UV absorber "Tinuvi
n-P "(manufactured by Ciba Geigy) and solid content ratio 90:
A surface protective film was obtained in the same manner as in Example 1 except that a coating material having a concentration of 15% by weight, which was mixed with No. 10 and the cross-linking agent used in Example 3 was added in the same manner, was applied. It turns out that there is anxiety about the UV blocking property.

[0053]

[Table 1]

[0054]

According to the surface protective film of the present invention,
Since the specific coating layer was formed on the surface of the plastic film, the following excellent effects could be obtained.

First, the surface protective film of the present invention has an excellent UV blocking property without causing bleed-out and the like, and is also excellent in its durability.

Further, since the surface protective film of the present invention has excellent blocking properties and excellent thermal laminating properties, it is excellent in handleability during processing without damaging the mating base material.

Since the surface protective film of the present invention has the above-mentioned excellent properties, it can be used in various substrates (plastic,
It can be applied to overlays of glass, metal, cloth, paper, wood, inorganic materials, etc.) and overlays of printed matter such as posters and signs.

Claims (9)

[Claims] 1. A surface protective film comprising a plastic film and a coating layer containing an ultraviolet absorbing acrylic resin and a heat-adhesive resin as main components on at least one surface of the plastic film. 2. The surface protective film according to claim 1, wherein the glass transition temperature of the ultraviolet absorbing acrylic resin is in the range of 30 to 90 ° C. 3. The glass transition temperature of the heat-adhesive resin is 0-5.
The surface protection film according to claim 1 or 2, which is in the range of 0 ° C. 4. A glass transition temperature (Tg1) of an ultraviolet absorbing acrylic resin and a glass transition temperature (Tg) of a thermoadhesive resin.
The surface protection film according to any one of claims 1 to 3, wherein g2) has a relationship of Tg1> Tg2. 5. A weight mixing ratio (A /) of the ultraviolet absorbing acrylic resin (A) and the heat-adhesive resin (B) in the coating layer.
B) is the range of 5 / 95-80 / 20, The surface protection film in any one of Claims 1-4 characterized by the above-mentioned. 6. The surface protective film according to claim 1, wherein the laminated thickness of the coating layer is in the range of 1 to 200 μm. 7. The surface protective film according to claim 1, wherein the coating layer is crosslinked. 8. The surface protective film according to claim 1, wherein the plastic film is a fluororesin film. 9. The surface protective film according to claim 8, wherein the fluororesin film is composed of a composition containing an ethylene-4 fluoroethylene copolymer as a main component.