JP2756905B2 - Paint film protection sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet for protecting a paint film, which is hard to deform the paint film and is suitable for protecting the surface of automobile bodies and parts, painted steel plates and the like.

[0002]

2. Description of the Related Art When a painted automobile or its parts are loaded on a truck or ship and transported to a remote place such as abroad, painting with various floating matters such as dust, dust, rain or collision objects. There is a need for a means for preventing damage to the film, blurring or discoloration of the film. Heretofore, as a preventive measure, a method in which a coating material containing wax as a main component is applied in a thickness of 5 to 40 μm has been known. However, it is difficult to form a wax coating to a uniform thickness, and uniform protection cannot be obtained, it is easy to get dirty, it is susceptible to acid rain, and wax etc. penetrates into the coating film and causes discoloration. In addition, there is a problem that a great deal of labor is required for applying and removing the wax coating film, and it is easy to cause environmental problems such as use of a solvent and treatment of a waste liquid.

[0003] On the other hand, various surface protection sheets having an adhesive layer provided on a supporting substrate are known, and for an adherend having a coating film, a radiation-curable adhesive having a low glass transition point is used. There has been proposed a device provided with an agent layer (Japanese Unexamined Patent Application Publication No.
-199184). According to such a sheet system, the above-mentioned problem can be overcome. However, when such a surface protection sheet is adhered to a coating surface of an automobile or the like, whether a low molecular weight component such as a fatty acid glycerin ester in the coating film is sucked out due to a rise in temperature due to outdoor transportation or the like, or on the surface protection sheet side. This caused a problem that the coating film was thinned due to migration, and adhesion marks of the protective sheet clearly appeared on the coating film surface. Especially for low Tg type coatings, 5
At 0 ° C, about 10 hours of adhesion and depth of 0.1-0.5
The occurrence of adhesion marks of about μm is customary.

[0004]

SUMMARY OF THE INVENTION The present invention can prevent the thinning of the coating film due to the migration of low molecular weight components in the coating film and protect the surface of the coating film even when the temperature rises when the vehicle is transported outdoors, for example. An object of the present invention is to develop a sheet for protecting a coating film, which does not cause adhesion traces of the sheet for coating, and has excellent protective properties of the coating film and excellent releasability without adhesive residue which becomes a contaminant.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a sheet for protecting a paint film, wherein a rubber-based pressure-sensitive adhesive layer containing a fatty acid glycerin ester is provided on a supporting substrate.

[0006]

[Function] By using a rubber-based pressure-sensitive adhesive containing a fatty acid glycerin ester, it is possible to prevent the low molecular weight components in the coating film from migrating to the protective sheet even when the temperature rises due to transportation outdoors, and to make the coating film thin. No phenomenon occurs and no trace of adhesion of the protective sheet is formed on the coating film surface. In addition, the coating film is excellent in the protection property of the coating film in a state where the protective sheet is adhered, and can be easily peeled off without leaving glue residue as a contaminant.

[0007]

Illustrative Components of the Invention The sheet for protecting a coating film of the present invention has a rubber-based pressure-sensitive adhesive layer containing a fatty acid glycerin ester on a supporting substrate. As the supporting substrate, any suitable one may be used, and generally, a plastic film, a porous film, paper, a nonwoven fabric, or the like is used. The thickness of the supporting base material is 300 μm or less, especially 10 to 10
0 μm is common, but not limited to this.

For the formation of the pressure-sensitive adhesive layer, for example, one or more rubber-based polymers such as natural rubber, polyisobutylene, ABA type block polymer and the like are used as components. An appropriate rubber-based pressure-sensitive adhesive containing a softener can be used. It may contain appropriate additives such as a filler, a pigment, an antioxidant, and a stabilizer.

The rubber-based polymer which is preferable from the viewpoint of long-term stability of performance is a non-curable polyisobutylene-based polymer having no unsaturated bond, or an A-polymer comprising a polystyrene block-ethylene / butylene copolymer block-polystyrene block. BA type block polymer and the like. As the polyisobutylene-based polymer, a mixture of a high-molecular-weight type having a viscosity average molecular weight of 100,000 or more and a low-molecular-weight type having a viscosity average molecular weight of less than 100,000 in a weight ratio of 1: 0 to 8: 1 is particularly preferably used. sell.

The tackifier or softener which the rubber-based pressure-sensitive adhesive may contain may be any suitable one, and preferably has good compatibility with the rubber-based polymer. Typical tackifiers include, for example, hydrocarbon resins, alkylphenol resins, terpene resins, and the like.

Examples of the general softener include polyisobutylene having a low molecular weight when the rubber polymer is polyisobutylene, and paraffin oil when the rubber polymer is an ABA type block polymer. .

Examples of the fatty acid glycerin ester blended in the rubber-based pressure-sensitive adhesive layer include glycerin (mono, di, tri) caprate, glycerin (mono, di, tri) laurate, and (mono, di, tri) laurate. Examples include glycerin myristate and coconut oil, and coconut oil is particularly preferred.

The fatty acid glycerin ester is used in a state of being mixed with a rubber-based pressure-sensitive adhesive. The amount of the fatty acid glycerin ester is appropriately determined depending on the compatibility and the thickness of the pressure-sensitive adhesive layer to be formed. Based on a pressure-sensitive adhesive layer having a thickness of 15 μm, 25 parts by weight or less per 100 parts by weight of the rubber-based pressure-sensitive adhesive,
A blending of ２０20 parts by weight is preferred. If the amount exceeds 25 parts by weight, the fatty acid glycerin ester may bleed to the surface of the pressure-sensitive adhesive layer to contaminate the surface of the coating film. If the amount of the fatty acid glycerin ester is too small, the effect of the addition is poor and adhesion traces are easily generated.

The sheet for protecting the coating film is formed by, for example, a method of applying a solution of a rubber-based pressure-sensitive adhesive containing a fatty acid glycerin ester in a solvent or a hot melt to a support substrate, or transferring the pressure-sensitive adhesive layer formed on a separator. It can be performed according to a known method for forming an adhesive sheet such as a method for attaching.

The thickness of the pressure-sensitive adhesive layer to be formed may be appropriately determined, and is generally 200 μm or less, especially 5 to 50 μm. The pressure-sensitive adhesive layer is protected by a temporary attachment, if necessary, until it is put to practical use.

The sheet for protecting a paint film of the present invention is, for example, an automobile body or its parts coated with a melamine-alkyd-based, melamine-acrylic, or urethane-based paint film, or a metal plate such as a steel plate. It is preferably used for impact of minute objects on an adherend having a coating film made of the molded product or the like, surface protection from chemicals, and the like. Especially,
It can be used advantageously when the temperature rises due to outdoor transport or when it is bonded for a long time.

Example 1 A coconut oil was added to a toluene solution of a rubber-based adhesive comprising a mixture of 75 parts (parts by weight, hereinafter the same) of polyisobutylene having a viscosity average molecular weight of 1,000,000 and 25 parts of polyisobutylene having a viscosity average molecular weight of 80,000. 5 parts were blended, and the blended liquid was applied to a film of polypropylene / polyethylene (weight ratio: 9/1) having a thickness of 40 μm and dried at 80 ° C. for 2 minutes to have an adhesive layer having a thickness of 15 μm. A sheet for coating protection was obtained.

Example 2 A sheet for protecting a paint film was obtained in the same manner as in Example 1 except that the blending amount of coconut oil was changed to 10 parts.

Example 3 A sheet for protecting a paint film was obtained in the same manner as in Example 1 except that the amount of the coconut oil was changed to 20 parts.

Example 4 A sheet for protecting a paint film was obtained in the same manner as in Example 2 except that glycerin trilaurate was used instead of coconut oil.

Example 5 As a rubber-based pressure-sensitive adhesive, 100 parts of an ABA type block polymer (Clayton G-1657, manufactured by Shell Chemical Co., Ltd.) composed of a polystyrene block, an ethylene / butylene copolymer block, and a polystyrene block, A sheet for protecting a paint film was obtained in the same manner as in Example 2 except that a mixture of 40 parts of a hydrogenated petroleum resin (ALCON P-100, manufactured by Arakawa Chemical Co., Ltd.) was used.

Comparative Example 1 A sheet for protecting a paint film was obtained in the same manner as in Example 1 except that coconut oil was not blended.

Comparative Example 2 A sheet for protecting a paint film was obtained in the same manner as in Example 1 except that the blending amount of coconut oil was changed to 30 parts.

Evaluation Test The following tests were performed on the coating film protecting sheets obtained in Examples and Comparative Examples. After the sheet for protecting the coating film is bonded at room temperature to a plate having an alkyd melamine coating film having a glass transition point of 60 ° C. and containing a glycerin ester of residual fatty acid, the film is taken out in an atmosphere of 80 ° C. for 24 hours and taken out. 3
After leaving for a period of time, the sheet for protecting the paint film was peeled and removed, and the presence or absence of the adhesive residue, particularly, the presence or absence of the adhesive residue in the portion corresponding to the peripheral portion of the sheet for protecting the paint film was examined.

Adhesion marks The alkyd / melamine coating film after the above-mentioned adhesive residue test is observed, and it is visually determined whether or not there is a step in the coating film.
In particular, the presence or absence of a step at a portion corresponding to the peripheral portion of the coating film protection sheet is examined. No step (recess) due to migration of the fatty acid glycerin ester in the alkyd / melamine coating film to the coating film protection sheet is observed. The case was determined to be no, and the case recognized was determined to be present.

The results are shown in the following table.

[0027]

According to the sheet for protecting a coating film of the present invention, even when the glass transition point of the coating film is low and the temperature rises, the migration of low molecular weight components in the coating film to the protection sheet can be prevented. In addition, the thinning of the coating film can be prevented, and no trace of adhesion of the protective sheet is formed on the coating film surface. In addition, it is excellent in protection of the coating film in the bonded state, and can be easily peeled off from the coating film without leaving glue residue as a contaminant.

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Takeshi Eda 4-171-1, Higashi-Hachiman, Hiratsuka-shi, Kanagawa Prefecture Inside Kansai Paint Co., Ltd. (72) Tatsuyoshi Tatsuno 4-171-1, Higashi-Hachiman, Hiratsuka-shi, Kanagawa Kansai Paint Inside (72) Inventor Tsuyoshi Inoue 1-2-1, Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation Inside (72) Inventor Kenichi Shibata 1-2-1, Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Inside (72) Inventor Yutaka Kuwahara 1-1-2 Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation (72) Inventor Tatsuo Wada 1-2-1, Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Incorporated (58) Fields surveyed (Int.Cl. ⁶ , DB name) C09J 7/00-7 / 04,11 / 06,107 / 00-121/02

Claims (4)

(57) [Claims] 1. A sheet for protecting a coating film, comprising a support substrate provided with a rubber-based pressure-sensitive adhesive layer containing a fatty acid glycerin ester. 2. The coating film protecting sheet according to claim 1, wherein the amount of the fatty acid glycerin ester is 25 parts by weight or less per 100 parts by weight of the rubber-based pressure-sensitive adhesive. 3. The sheet according to claim 1, wherein the fatty acid glycerin ester is coconut oil. 4. The method according to claim 1, wherein the rubber-based pressure-sensitive adhesive is polyisobutylene or / and / or
And ABA comprising a polystyrene block-ethylene / butylene copolymer block-polystyrene block
The sheet for protecting a coating film according to claim 1, comprising a mold block polymer as a component.