JPH10140113A - Sheet for protecting coating film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a sheet for protecting coating films which hardly exhibits spontaneous peeling and can be easily peeled off without leaving contaminants behind even after having been stuck to a coating film for a long term by forming, on a substrate, a rubbery self-adhesive layer from a compsn. prepd. by compounding a rubbery polymer with a small amt. of a terpene-modified phenol resin. SOLUTION: This sheet is prepd. by forming, on a substrate, a rubbery self-adhesive layer from a compsn. prepd. by compounding 100 pts.wt. rubbery polymer with 0.5-1 pt.wt. terpene-modified phenol resin. The compsn. may further contain other polymers and aditives such as a tackifier, a softener, a filler, a pigment, and an antioxidant. The sheet is suitable for protecting various coated surfaces, such as those of automotive bodies or parts or articles made of steel sheets, from chemicals or from the collision of minute objects; it is esp. useful in high- speed transport at low temps. wherein spontaneous peeling tends to occur or in the case when it is kept stuck to a coated surface for a long term.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a protective film for coatings which is hardly spontaneously peeled off and can be easily peeled off without leaving any contaminants after long-term bonding, and is suitable for protecting the surface of automobile bodies, parts, painted steel plates and the like. Regarding the sheet.

[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, due to suspended matters such as dust and dirt, rain and stones, or collision objects. There is a need for a means for preventing damage, gloss blurring or discoloration of the coating film.

Heretofore, as such a preventive means, a wax-based coating material having a thickness of 5 to 20 μm has been known. However, it is difficult to form a wax coating to a uniform thickness, and it is difficult to obtain a uniform coating, it is easy to become dirty and vulnerable to acid rain, and a great deal of labor is required to apply and remove the wax coating. In short, there is a problem that environmental problems such as use of a solvent and treatment of a waste liquid are easily induced.

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). The present applicant has also proposed a coating film protection sheet using a rubber-based polymer such as polyisobutylene as an adhesive (JP-A-6-73352).
According to such a sheet system, the above-mentioned problem can be overcome.

[0005] However, there is a problem that the protective sheet adhered to the coating film is spontaneously peeled off, for example, in the case of transporting at high speed by loading on a truck or the like. Such a peeling phenomenon occurs particularly frequently during transportation at a low temperature such as in winter.

[0006]

The present invention has an excellent protective function that does not peel off naturally from a coating film even during high-speed transportation at a low temperature, and can be easily peeled off without leaving contaminants even after long-term adhesion. Accordingly, an object of the present invention is to develop a sheet for protecting a coating film which does not require a cleaning operation of the coating film after peeling.

[0007]

The present invention is characterized in that a rubber-based adhesive layer containing 0.05 to 1 part by weight of a terpene-modified phenolic resin per 100 parts by weight of a rubber-based polymer is provided on a supporting substrate. A sheet for protecting a coating film is provided.

[0008]

By using a combination of a rubber-based adhesive layer and a terpene-modified phenolic resin, spontaneous peeling does not occur even in high-speed transportation under low temperatures such as in winter with a small amount of the terpene-modified phenolic resin. It is possible to obtain a sheet for protecting a coating film which can have sufficient adhesive strength and can be easily peeled off without leaving contaminants on the coating film surface even after long-term bonding. Therefore, it is possible to avoid the necessity of cleaning the coating film after the protective sheet is peeled off.

In the above, it is possible to achieve an adhesive force that does not cause spontaneous peeling by high-speed transportation at a low temperature even with a large amount of a tackifier, but in that case, peeling after long-term bonding becomes difficult, Further, it is difficult to remove the contaminants from the coating film surface without leaving any contaminants, and a practically usable coating film protection sheet cannot be obtained.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The sheet for protecting a paint film according to the present invention is coated on a supporting substrate in an amount of 0.1 to 100 parts by weight of a rubber-based polymer.
It is provided with a rubber-based pressure-sensitive adhesive layer containing 0.5 to 1 part by weight of a terpene-modified phenolic resin.

As the supporting substrate, any suitable substrate may be used. Generally, a film made of a plastic such as polyethylene, polypropylene, or polyester, a porous film having air permeability, paper, nonwoven fabric, or the like is used. The thickness of the supporting substrate is 5 to 300 μm, preferably 10 to 10
0 μm is common, but not limited to this.

For forming the rubber-based pressure-sensitive adhesive layer, for example, a pressure-sensitive adhesive using a suitable rubber-based polymer such as natural rubber, polyisobutylene, butyl rubber, or an A / B / A-type block polymer such as styrene / butadiene / styrene. Can be used. Rubber polymers that can be preferably used from the viewpoint of long-term stability of adhesive properties such as adhesive strength and releasability do not contain or have a low content of unsaturated bonds.

Examples of the rubber-based polymer which can be preferably used include polyisobutylene and butyl rubber, polystyrene block-ethylene-butylene copolymer block-polystyrene block copolymer, and polystyrene block-ethylene-propylene copolymer block. −
Styrene AB such as polystyrene block copolymer
-A-type block polymers and the like.

As the base polymer, one or more kinds of rubber-based polymers can be used, and the same kind of polymers of different grades having different molecular weights can also be used in combination. In this case, the combination system of polyisobutylene is preferably 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 of less than 100,000 in a weight ratio of 95: 5 to 50:50. Can be used.

Examples of the terpene-modified phenolic resin blended in the rubber-based pressure-sensitive adhesive layer include phenolic resins modified with an appropriate terpene such as α-pinene, β-pinene and rosin. Among them, those having a softening point of 60 to 200 ° C., particularly 80 to 150 ° C., are more preferable than points of adhesive properties such as adhesive strength and releasability.

The compounding amount of the terpene-modified phenolic resin is 0.05 to 1 per 100 parts by weight of the rubber-based polymer.
Parts by weight. If the amount is less than 0.05 part by weight, the effect of the compounding effect is poor, and if it exceeds 1 part by weight, the adhesive force is increased and the releasability is poor, and contaminants tend to remain after peeling. The compounding amount of the terpene-modified phenolic resin is preferably 0.1 parts by weight or more, particularly 0.2 parts by weight, per 100 parts by weight of the rubber-based polymer, in order to prevent spontaneous peeling and leave no contaminants and easy peelability. 0.8 parts by weight.

The sheet for protecting the coating film is formed, for example, by preparing a rubber-based polymer solution containing a terpene-modified phenolic resin using an appropriate solvent such as toluene, hexane, cyclohexane or heptane, and using the solution as a supporting base material. The method can be carried out according to a known method for forming an adhesive sheet, such as a method of applying or a method of transferring an adhesive layer formed on a separator.

The thickness of the pressure-sensitive adhesive layer to be formed may be determined as appropriate, and is generally 100 μm or less, preferably 1 to 50 μm, particularly 3 μm.
２０20 μm. If necessary, the adhesive layer is protected by temporarily attaching a separator or the like until it is practically used.

In the formation of the sheet for protecting the coating film, if necessary, the rubber-based pressure-sensitive adhesive layer may contain various kinds of additives such as polymers, tackifiers, softeners and fillers, and stabilizers such as pigments and antioxidants. Compounding agents can be added. The compounding agent is appropriately used within a range that can maintain the above-mentioned adhesive properties and the like.

Incidentally, the above-mentioned polymers include, for example, poly (meth) acrylate, polybutadiene,
Examples include polystyrene, polyisoprene, poly-α-olefin, natural rubber, polyester and polyurethane, polyacrylonitrile and polyamide.

Examples of the tackifier include rosin resin and petroleum resin. As a softener,
For example, a process oil, a petroleum-based softener, and the like can be given. Examples of the filler or pigment include calcium oxide, magnesium oxide, silica, zinc oxide, and titanium oxide.

The sheet for protecting a paint film of the present invention can be used for impact of minute objects against an adhered body such as an automobile body or parts thereof coated with various paint films, or a metal plate such as a steel plate or a molded product thereof. It is preferably used for protecting surfaces from chemicals and chemicals. In particular, it can be advantageously used in cases where spontaneous peeling is likely to occur due to high-speed transportation at a low temperature, etc., or when bonding is performed for a long period of time.

[0023]

【Example】

Example 1 A weight average molecular weight (hereinafter the same) in terms of polystyrene measured by GPC (gel permeation chromatography) is 8
90,000 (the same hereinafter) 90 parts of polyisobutylene (parts by weight,
A terpene-modified phenol resin (YS Polystar S145, manufactured by Yasuhara Yushi Kogyo Co., Ltd.) was added to a solution obtained by dissolving 10 parts of 30,000 polyisobutylene in 700 parts of toluene.
0.5 part was blended, the blended liquid was applied to a polypropylene film having a thickness of 40 μm, and dried at 80 ° C. for 3 minutes to obtain a sheet for protecting a coating film having a rubber-based adhesive layer having a thickness of 10 μm. .

Example 2 A sheet for protecting a coating film was obtained in the same manner as in Example 1 except that the amount of the terpene-modified phenol resin was changed to 0.1 part.

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 terpene-modified phenol resin was changed to 0.8 part.

Example 4 As a rubber-based pressure-sensitive adhesive, 100 parts of an A.B.A type block polymer (Clayton G-1657, manufactured by Shell Chemical Co., Ltd.) composed of a polystyrene block-ethylene / butylene copolymer block / polystyrene block; 30 parts of hydrogenated petroleum resin (Arakawa Chemical Co., Inc., Alcon P-100),
A sheet for protecting a paint film was obtained in the same manner as in Example 1 except that a mixture of 0.5 part of a terpene-modified phenol resin was used.

Example 5 As a rubber-based pressure-sensitive adhesive, an A.B.A type block polymer composed of a polystyrene block-ethylene-propylene copolymer block-polystyrene block (manufactured by Kuraray Co., Ltd.)
Septon 2023) 100 parts and Alcon P-100:
A sheet for protecting a coating film was obtained in the same manner as in Example 1 except that a mixture of 20 parts and 0.5 part of a terpene-modified phenol resin was used.

Comparative Example 1 0 parts of terpene-modified phenolic resin (no blending)
A sheet for protecting a paint film was obtained in the same manner as in Example 1 except that

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 the terpene-modified phenol resin was changed to 5 parts.

Comparative Example 3 A sheet for protecting a coating film was obtained in the same manner as in Example 1 except that a terpene resin (YS Resin PX1150, manufactured by Yasuhara Yushi Kogyo Co., Ltd.) was used instead of the terpene-modified phenol resin.

Evaluation Test The following characteristics were examined for the coating film protecting sheets obtained in Examples and Comparative Examples. Low temperature adhesiveness A sheet for protecting the coating film is adhered to a coated plate having an alkyd melamine coating film having a glass transition point of 95 ° C (the same applies hereinafter) by reciprocating a 2 kg rubber roll at 23 ° C once and stored at 0 ° C for 1 hour. Thereafter, the sheet for protecting the coating film was peeled off in an atmosphere of 0 ° C., and the adhesive strength (180 ° peel, peeling speed 300 mm / min, the same applies hereinafter) was examined.

Peelability A sheet for protecting the paint film was adhered to the coated plate by reciprocating a 2 kg rubber roll at 23 ° C. once and stored at 80 ° C. for 48 hours.
The coating film protection sheet was peeled off by leaving it at room temperature for 3 hours, and the adhesive strength and peel feeling were examined.

Stainability In the peelability test, the surface of the coating film after peeling off the protective sheet was visually observed to check for contamination.

The results are shown in Table 1.

[Table 1]

From the table, it can be seen that the sheet for protecting the paint film of the embodiment has:
It can be seen that, even at a low temperature, a suitable adhesive force that can withstand high-speed transportation and maintain an adhesive state is maintained, and that it can be easily peeled off without leaving contaminants after long-term bonding.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI C09J 161: 14) (C09J 123/22 161: 14) (C09J 153/00 161: 14) (72) Inventor Kenichi Shibata Osaka 1-1-2 Shimohozumi, Ibaraki-shi Nitto Denko Corporation (72) Inventor Mitsuru Mitsuda 1-1-2 Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation (72) Inventor Koharu Matsui Higashiratsuka, Kanagawa Prefecture 4-17-1, Yawata Kansai Paint Co., Ltd. (72) Inventor Takeshi Eda 33-1, Kanzakicho, Amagasaki City, Hyogo Prefecture Kansai Paint Co., Ltd. (72) Inventor Hiroshi Ueda 33, Kanzakicho Amagasaki City, Hyogo Prefecture No. 1 Kansai Paint Co., Ltd.

Claims (2)

[Claims] Claims: 1. An amount of 0.1% by weight per 100 parts by weight of a rubber-based polymer.
A sheet for protecting a paint film, comprising a support base material provided with a rubber-based pressure-sensitive adhesive layer containing from 0.5 to 1 part by weight of a terpene-modified phenolic resin. 2. The coating film protecting sheet according to claim 1, wherein the rubber-based pressure-sensitive adhesive layer comprises at least one of polyisobutylene and styrene-based ABA type block polymer as a base polymer.