JP2000119613A - Surface protection film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface protection film which inhibits generation of adhesion marks of protection films on coating surfaces, even in an outdoor environment, and exerts a good protection property on the applied surface and a high release property allowing no paste remnants which become pollutants. SOLUTION: An adhesive layer, which mainly comprises an adhesion imparting agent comprising natural resins, a polyoxyethylene alkyl ether anion salt surfactant wherein the HLB(hydrophile-lipophile balance) of the original polyoxyethylene alkyl ether is from 3 to 10 and at least one chosen from polyisobutylene, a butyl rubber and a polybutene, is formed on a polyolefin support base material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface protective film which hardly deforms a coating film and is suitable for protecting the surface of a coated steel plate or the like.

[0002]

2. Description of the Related Art Heretofore, as a surface protective film for a color steel sheet or an automobile body, the surface of which has been subjected to a coating treatment, a film provided with a rubber-based pressure-sensitive adhesive layer on a supporting base material is known. However, when the protective film is peeled off from the painted surface, there is a problem that the adhesion mark remains on the coated film as time passes. Further, when the coating film becomes soft, this adhesion mark appears remarkably and it is difficult to use. This adhesion trace is generated due to ultraviolet rays, temperature rise, acid rain, and the like due to outdoor storage and the like. For example, an adhesion trace having a depth of about 0.5 to 2.0 μm is generated in an atmosphere at 80 ° C. for one day.

[0003]

As the inventors of the present invention have intensively studied to overcome the above-mentioned problems, as a mechanism of the formation of the adhesion trace, the low molecular weight component in the coating film is protected by surface protection. It was clarified that the coating film was thinned by being absorbed and transferred to the film, and that the low molecular weight component in the protective film was absorbed by the coating film and that the coating film was swollen. This means that, for example, in the case of an incompletely cured soft coating made of a two-component urethane coating (hereinafter referred to as a soft coating), more low-molecular-weight components remain than in a normal coating, and adhesion marks become remarkable. Also match. Therefore, the present invention provides a surface protective film which is excellent in the protective property of the painted surface and the peeling property with no adhesive residue which becomes a contaminant, without the adhesion mark of the protective film being generated on the painted surface even in an outdoor environment. The purpose is to provide.

[0004]

According to the present invention, a natural resin-based tackifier and an original polyoxyethylene alkyl ether having an HLB (Hydrophile-lypophile balance) of 3 to 1 are used.
A polyoxyethylene alkyl ether-based anionic salt surfactant which is 0, polyisobutylene, butyl rubber,
The present invention relates to a surface protective film in which a pressure-sensitive adhesive layer containing at least one of polybutene as a main component is provided on a polyolefin-based support base material.

[0005] Due to the adhesive of the above composition, the low molecular weight component of the coating film can be reduced even in the outdoor environment such as dust, iron powder, acid rain, bird droppings, etc. during transportation or storage of the coated product. It is possible to prevent thinning and swelling of the coating film due to migration and migration of low molecular weight components in the protective film. In particular, in the case of a soft coating film, it is difficult to generate air bubble marks and film edge marks after the film is attached, and it can be easily peeled off without leaving adhesive on the adhesive.
A protective film for automobiles that has excellent protection against suspended matter such as sand and collision objects, can easily and uniformly protect the coating film, and maintains the advantages of a surface protective film that can be easily peeled off without causing environmental problems. can do.

The use of a polyoxyethylene alkyl ether-based anionic salt surfactant in which the original polyoxyethylene alkyl ether has an HLB of 3 to 10 is required to prevent the migration of a low molecular weight in a coating film and the protection film. The purpose is to prevent the thinning and swelling of the coating film due to the migration of the low molecular weight inside. In order to suppress the movement of the low molecular weight component, a molecular barrier of a surfactant is formed between the pressure-sensitive adhesive layer and the coating film side (more precisely, the surface of the pressure-sensitive adhesive layer) to suppress the movement of the low molecular weight component, We decided to suppress the deformation of the coating. Also,
It is necessary to use a surfactant that does not move and does not migrate to the coating film. Therefore, by adding a surfactant satisfying these conditions to the adhesive, it is possible to suppress the movement of the low molecular weight component from the coating film side and the movement from the adhesive film side, and in a severe environment, Also, the deformation of the coating film can be almost prevented.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a surfactant used as an additive is represented by the following general formula [RO- (CH2 CH2 O) n-acid] l Mm R: alkyl, alkyl allyl group, acid: Acid part,
M: metal atom, l, m, n: a polyoxyethylene alkyl ether-based anion salt represented by any integer. This HLB is 3-10, preferably 5
８8. If the HLB exceeds 10, the compatibility with the pressure-sensitive adhesive is lost, which is not preferable. If the HLB is less than 3, the water-soluble properties are almost lost, and the desired properties cannot be obtained.
The amount of addition varies depending on the degree of the effect of preventing the deformation of the coating film, the compatibility, the thickness of the formed pressure-sensitive adhesive layer, and the like, with respect to 100 parts by weight of the rubber as the main component of the pressure-sensitive adhesive, but is 1 to 5 parts by weight. If the amount is less than 1 part by weight, the expected effect of suppressing the deformation of the coating film cannot be obtained. If the amount exceeds 5 parts by weight, the decrease in adhesive strength and transfer due to the releasing effect become remarkable, which is not preferable.

[0008] HLB is an index showing the balance between hydrophilicity and lipophilicity, and a value obtained from HLB = E / 5 and E: oxyethylene content (%) from Griffin's formula was adopted. Examples of the tackifier include rosin, rosin derivative, terpene resin, terpene phenol resin, dammar, copearl, and shellac-based natural resin. In particular, terpene-based pinene and dipentene have good compatibility with polyisobutylene, which is a main component of the pressure-sensitive adhesive, and have little influence on the deformation of the coating film. The weight average molecular weight is preferably from 100 to 7000, but is not limited thereto. The amount of addition is 1 to 10 parts by weight based on 100 parts by weight of the rubber as the main component of the pressure-sensitive adhesive. If the amount is less than 1 part by weight, the effect of improving the adhesive strength cannot be obtained. If the amount exceeds 10 parts by weight, transfer to the coating film or adhesive residue due to a decrease in the cohesive force of the adhesive is not preferred.

The main components of the pressure-sensitive adhesive include polyisobutylene, butyl rubber, and polybutene. Polyisobutylene is a polymer of isobutylene. As the butyl rubber, a copolymer of isobutylene and isoprene as a main component, and a polymer obtained by polymerizing or chlorinating a monomer having a crosslinkable functional group such as a carboxyl group or a hydroxyl group can be used.
Polybutene is a copolymer of isobutylene and structural isomers such as 1-butene and n-butene. One or a mixture of these is used. Weight average molecular weight is 50-200
It is necessary to be ten thousand. If the molecular weight is less than 500,000, the cohesive strength of the adhesive force and the weather resistance are insufficient, and the amount of the moving low molecular weight component increases, so that the deformation of the coating film becomes remarkable, which is not preferable. If it exceeds 2,000,000, the adhesive strength in the low temperature range will decrease,
Undesirably, the coating film is easily deformed at the edge portion such as a bubble or a parting portion where stress is easily applied. Further, it is preferable to add a weather resistance improver for improving the weather resistance of the pressure-sensitive adhesive. Examples of the weather resistance improver include antioxidants such as amines, quinolines, hydroquinones, phenols and phosphites, antioxidants, and salicylic acid derivatives, benzophenones, benzotriazoles, and hindered amines. And benzotriazole-based ultraviolet absorbers are particularly preferred because they are excellent in improving the compatibility and weather resistance. The amount of addition is 0.1 parts with respect to 100 parts by weight of the rubber as the main component of the adhesive.
６6 parts by weight. If the amount is less than 0.1 part by weight, the effect of improving the weather resistance is not obtained, and if it exceeds 6 parts by weight, the coating film is remarkably deformed, which is not preferable.

The polyolefin film used as a supporting substrate remains in the form of a mixture of a homopolymer of propylene and ethylene, a copolymer or a mixture of a homopolymer and a copolymer. It is 40% by weight. If the ethylene content is less than 5% by weight, the cold resistance (adhesion at around -20 ° C) decreases, and if it exceeds 40% by weight, the film becomes too soft, which is not preferable. Furthermore, for modification,
-Olefins and further monomers such as vinyl acetate and methyl methacrylate may be copolymerized. Also, for the purpose of improving the weather resistance, heat resistance, workability and workability of the support base material,
Antioxidants, ultraviolet absorbers, lubricants, plasticizers and the like may be added. However, an excessively large amount affects the deformation of the coating film. The color of the supporting base material is preferably a Munsell dye-based white color of N8 or more. Colored films made of carbon black, etc., have excellent light shielding and light shielding properties.
However, since the heat rise due to absorption is large and the temperature rises to 80 ° C. or more in direct sunlight in summer, a problem such as thermal deformation tends to occur in a soft coating film having a low Tg. When the Munsell dye is N8 or more white, the temperature rise is preferably as small as 60 to 70 ° C. However, in the case of white, the weather resistance of the supporting substrate itself is insufficient due to the small light-shielding properties of the pigment, and it is necessary to add a weather resistance improving agent.

Examples of the weather resistance improver include amine-based, quinoline-based, hydroquinone-based, phenol-based and phosphite-based anti-aging agents, antioxidants, or salicylic acid derivatives, benzophenone-based, benzotriazole-based, and hindered amine-based agents. UV absorbers, light stabilizers and the like, especially hindered amine UV absorbers are compatible,
It is preferable because the effect of improving weather resistance is excellent. The addition amount is preferably 0.1 to 10 parts by weight. If the amount is less than 0.1 part by weight, the effect is not obtained. If the amount exceeds 10 parts by weight, the coating film is notably deformed, which is not preferable. As pigments, titanium oxide,
White pigments such as calcium carbonate, barium sulfate, and zinc oxide are exemplified. The coloring of the olefin-based film is performed by adding a pigment or printing on the back surface of a supporting substrate, which is usually performed. The degree of coloring is 5% in the range of 190 to 370 nm in the maximum amount of ultraviolet light for improving the weather resistance of the film.
Or less, preferably 1% or less.

The surface protective film may be produced, for example, by applying a solution of a pressure-sensitive adhesive having the above composition or a hot melt to a supporting substrate, or by transferring an adhesive layer formed on a separator to the supporting substrate. It can be performed according to a known method for forming an adhesive film. The thickness of the pressure-sensitive adhesive layer to be formed may be appropriately determined, and is generally 200 μm or less,
0 μm is preferred. This is because the lower the component in the adhesive, the lower the low molecular weight component. The surface protective film of the present invention is used for protecting metal plates such as steel plates coated with various paints, and various types of adherends having painted surfaces of molded products from impact of minute objects and surface protection from chemicals and the like. It is preferably used. In particular, it is possible to prevent coating film deformation of a coated article when the temperature rises during storage or when sticky protection is performed for a long time.

[0013]

Next, examples of the present invention will be described, but the present invention is not limited to these examples. In the following description, all parts are parts by weight. Example 1 As a surfactant, H of polyoxyethylene alkyl ether was used.
2 parts of sodium polyoxyethylene alkyl ether sulfate having an LB of 8, 5 parts of a dipentene tackifier, and 4 parts of 2-hydroxy-4-n-octoxybenzophenone as an ultraviolet absorber were mixed with 10 parts of polyisobutylene having an Mw of 800,000.
0 parts of a toluene solution of a rubber-based adhesive
The adhesive solution was added to 100 parts of polypropylene / polyethylene (weight ratio = 1/1), 10 parts of titanium oxide as a pigment,
The composition was applied to a 40 μm support substrate comprising 0.5 parts of a hindered amine light stabilizer as a weather resistance improver, and dried at 80 ° C. for 5 minutes to obtain an adhesive film having an adhesive layer having a thickness of 7 μm.

Example 2 A surface protective film was obtained in the same manner as in Example 1 except that the HLB was changed to 5.

Example 3 A surface protective film was obtained in the same manner as in Example 1 except that the amount of the surfactant was changed to 5 parts.

Comparative Example 1 A surface protective film was obtained in the same manner as in Example 1 except that HLB was set to 1.

Comparative Example 2 A surface protective film was obtained in the same manner as in Example 1 except that HLB was changed to 14.

Comparative Example 3 A surface protective film was obtained in the same manner as in Example 1 except that the amount of the surfactant was changed to 10 parts.

Comparative Example 4 A surface protective film was obtained in the same manner as in Example 1 except that no surfactant was added.

Comparative Example 5 A surface protective film was obtained according to Example 1, except that no tackifier was added.

Comparative Example 6 The supporting substrate was polypropylene / polyethylene (weight ratio = 1).
A surface protection film was obtained in the same manner as in Example 1 except that only the method of (1/1) was used.

Evaluation Test Regarding the surface protective films obtained in Examples and Comparative Examples,
The following tests were performed. At room temperature, the above-mentioned surface protection film is attached with a 5 kg roller to a plastic plate having a soft coating film used for an automobile bumper. At this time, cut the film smaller than the painted plate, insert air bubbles and paste. The test piece was treated with a SWOM (Sunshine Weather Meter) for 100 hours, left at room temperature for 4 hours, and then a parting portion and a bubble portion where the film of the coated plate was adhered were examined, and a surface shape measuring device (VF-7500, K
EYENCE), the level difference between where the film was in contact and where it was not was measured. At the same time, adhesive residue was observed. The results are shown in Table 1.

[0023]

[Table 1] Unit: μm *: Floating occurs

[0024]

As described above in detail, according to the present invention, when transporting and storing painted products, dust, iron powder, acid rain, etc.
Even in an outdoor environment such as bird droppings, the migration of low molecular weight components in the coating film and the thinning and swelling of the coating film due to the migration of low molecular weight components in the protective film can be prevented, and It is possible to provide a surface protective film which is free from adhesion marks of the protective film, has excellent protective properties on the painted surface, and has excellent releasability with no adhesive residue remaining as a pollutant.

Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat II (reference) C08L 23:04) F term (reference) 4J002 AF012 AF022 AF032 BB171 BB181 BK002 CE002 CH053 FD313 FD342 GJ01 4J004 AA04 AA05 AA07 AA17 AB01 CA04 CC02 FA04 4J040 BA192 BA202 DA131 DA141 DN072 GA03 GA05 GA07 JA09 JB09 KA26 KA38 LA06 MA03 MA11 MB03 MB05 MB09 NA12 NA16 PA42

Claims (7)

[Claims] 1. A natural resin-based tackifier, a polyoxyethylene alkyl ether-based anionic salt surfactant in which the original polyoxyethylene alkyl ether has an HLB of 3 to 10, and polyisobutylene, butyl rubber and polybutene. A surface protection film comprising a pressure-sensitive adhesive layer containing at least one as a main component and provided on a polyolefin-based support base material. 2. The surface protection according to claim 1, wherein the pressure-sensitive adhesive layer comprises 1 to 10 parts by weight of a tackifier and 1 to 5 parts by weight of a surfactant based on 100 parts by weight of the rubber-based pressure-sensitive adhesive. the film. 3. The surfactant has a weight average molecular weight Mw of 200.
The surface protective film according to claim 1, wherein the molecular weight is from 5,000 to 5,000. 4. The surface protective film according to claim 1, wherein the surfactant is a polyoxyethylene alkyl ether sulfate. 5. A tackifier having a weight average molecular weight of 100 to 7
The surface protective film according to any one of claims 1 to 4, which has a molecular weight of 000. 6. The surface protective film according to claim 1, wherein the tackifier is a pinene polymer, a dipentene polymer, or a copolymer of the two, either singly or in combination. 7. The support base material is mainly composed of polypropylene and contains a polyethylene component in an amount of 5 to 40% by weight, and a hindered amine antioxidant as a weather resistance improver is used in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the resin component. The surface protective film according to any one of claims 1 to 6, wherein the surface protective film is a polyolefin-based film having a UV transmittance of 1% or less in a range of 190 to 370 nm and a color of 8 or more in a Munsell color system.