JP5019893B2 - Re-peelable pressure-sensitive adhesive sheet and coating film protection method - Google Patents

Description

The present invention relates to a re-peelable pressure-sensitive adhesive sheet and a method for protecting a coating film. More specifically, the present invention relates to a method for protecting a coating film applied to a plastic or metal part or the like without changing or changing the color of the coating film for a long time. The present invention relates to a re-peelable pressure-sensitive adhesive sheet excellent in peelability and a method for protecting an incompletely cured coating film.
The re-peelable pressure-sensitive adhesive sheet of the present invention is a re-peelable pressure-sensitive adhesive sheet that can be applied to a curable coating film that is insufficiently dried and a trace amount of solvent remains or is insufficiently cured after drying. It is a re-peelable pressure-sensitive adhesive sheet useful as a re-peelable pressure-sensitive adhesive sheet for protecting plastic parts coated with urethane-based paints such as bumpers.

When transporting automobiles, there are inconveniences such as dust and dirt, floating objects such as rain and pollen, collision objects such as sand, and contact with workers and the coating on the body and parts may be blurred, discolored, or damaged. . In order to prevent such an inconvenience, a wax-based material has been applied to a coating film of a car body or a part of an automobile, or a protective releasable pressure-sensitive adhesive sheet has been applied.
However, when a coating film applied to a vehicle body or a part is heat-cured, the curing reaction of the coating film may not sufficiently proceed even after passing through a drying furnace.
Above all, in order to reduce the weight of bumpers, which are one of the parts of automobiles, synthetic resin bumpers have been used instead of conventional metal ones. It is usually painted to make it easier. This synthetic resin bumper is also pasted with a protective re-peelable pressure-sensitive adhesive sheet in order to prevent the above disadvantages.
However, when the coating film applied to the bumper made of synthetic resin is heat-cured, the curing temperature cannot be increased in order to prevent adverse effects such as deterioration and deformation of the resin. For this reason, even after the coated resin bumper passes through the drying furnace, the coating film may not be sufficiently dried and a trace amount of solvent may remain or the curing reaction may not proceed sufficiently.
When a protective re-peelable adhesive sheet is applied to the coating film in such a state, “stepped (when the protective re-releasable adhesive sheet is applied, small wrinkles generated on the sheet and deformation due to lifting are transferred to the coating film. "Phenomenon in which the coating film is deformed)", "White blurring (Phenomenon in which the composition of the coating film is biased due to compatibility with the adhesive layer of the sheet, and the coating film appears white when the sheet is peeled off)", " A problem such as “adhesive residue (a phenomenon in which a part of the pressure-sensitive adhesive layer moves to a coating film when the sheet is peeled)” occurs.
The re-peelable pressure-sensitive adhesive sheet for coating film protection comprises a polyisobutylene-based pressure-sensitive adhesive layer provided on a support substrate (for example, Patent Document 1), butyl rubber or styrene-ethylene / butylene copolymer-styrene. An adhesive layer provided on a supporting substrate (for example, Patent Document 2), a polyisobutylene-based adhesive mixed with a small amount of an acrylic adhesive on a supporting substrate (for example, , Patent Document 3), an acrylic adhesive having a composition layer in which a polyfunctional isocyanate compound is blended, and a support substrate (for example, Patent Document 4), an ethylene-vinyl acetate-glycidyl methacrylate copolymer And a resin mainly composed of an ionomer in which molecules of an ethylene-methacrylic acid copolymer are bonded with metal ions (for example, Patent Document 5). Those in which a pressure-sensitive adhesive layer was cured to a supporting substrate (e.g., Patent Document 6) have been proposed.
However, the performance of the re-peelable pressure-sensitive adhesive sheet for protecting an automobile urethane-based coating film having the pressure-sensitive adhesive layer as described above is not yet sufficient.
In recent years, it has been proposed to use a pressure-sensitive adhesive or adhesive mainly composed of various silicone compounds (for example, Patent Documents 7 to 10). However, none of the documents discloses a re-peelable pressure-sensitive adhesive sheet for applying to an incompletely cured coating film.

Japanese Patent No. 2701020 Japanese Patent No. 3668322 Japanese Patent No. 2832565 Japanese Patent No. 3342777 JP-A-10-121022 JP 10-121010 A Japanese Patent No. 3751186 JP 2004-190013 A JP 2006-28311 A JP 2006-193598 A

  Under such circumstances, an object of the present invention is to solve the above-mentioned problems by using a specific silicone-based pressure-sensitive adhesive as a pressure-sensitive adhesive component.

  As a result of various researches, the present inventor has found that when a specific compound such as an ultraviolet absorber or a light stabilizer is contained in a base material or a primer applied to the base material, a silicone-based pressure-sensitive adhesive is used. In particular, the inventors found that the above-mentioned problems can be achieved by using a peroxide-curable silicone-based pressure-sensitive adhesive, and completed the present invention.

That is, the present invention provides the following (1) to (9),
(1) A re-peelable pressure-sensitive adhesive sheet for an incompletely cured coating film provided with a pressure-sensitive adhesive layer on a base sheet, wherein the pressure-sensitive adhesive layer is made of a peroxide-curable silicone pressure-sensitive adhesive. Re-peelable adhesive sheet,
(2) The re-peelable pressure-sensitive adhesive sheet according to (1), wherein the peroxide-curable silicone pressure-sensitive adhesive further contains a curing agent,
(3) The re-peelable pressure-sensitive adhesive sheet according to (2), wherein the curing agent is benzoyl peroxide,
(4) The releasable pressure-sensitive adhesive sheet according to any one of (1) to (3), wherein the base sheet is a polyethylene terephthalate sheet,
(5) The re-peelable pressure-sensitive adhesive sheet according to (4), wherein the polyethylene terephthalate sheet contains a weathering assistant,
(6) The releasable pressure-sensitive adhesive sheet according to any one of the above (1) to (5), wherein the pressure-sensitive adhesive layer is provided on a base material sheet via a primer layer.
(7) The releasable adhesive sheet according to any one of the above (1) to (6), which is a protective sheet for resin products,
(8) The re-peelable pressure-sensitive adhesive sheet according to any one of the above (1) to (7), which is wound in a roll shape, and (9) a peroxide-curable silicone pressure-sensitive adhesive on the base material sheet A method for protecting a coating film, comprising sticking a re-peelable pressure-sensitive adhesive sheet provided with a pressure-sensitive adhesive layer to an incompletely cured coating film.

  According to the present invention, it is possible to provide a re-peelable pressure-sensitive adhesive sheet that is not easily altered or discolored, particularly on a car body or a part of an automobile, and has excellent peelability after being applied for a long time. The re-peelable pressure-sensitive adhesive sheet of the present invention is used for protecting a coating film in which a trace amount of solvent remains or curing is insufficient due to insufficient drying immediately after drying, particularly in plastic parts such as painted automobile bumpers. It is useful as a re-peelable pressure-sensitive adhesive sheet.

Hereinafter, the peroxide curable silicone pressure-sensitive adhesive provided on the re-peelable pressure-sensitive adhesive sheet of the present invention will be described.
The peroxide-curing silicone pressure-sensitive adhesive is formed of a silicone rubber that is a long-chain polymer of polydimethylsiloxane and a silicone resin having a three-dimensional structure. In order to crosslink the base resin, an organic peroxide such as benzoyl peroxide is used.
Some silicone-based pressure-sensitive adhesives are of addition reaction type, and this is based on a mixture of a silicone resin component and a silicone rubber component, an alkenyl group-containing main agent and a hydrosilyl group (SiH group) -containing crosslinking agent, and platinum. It consists of a system curing catalyst.
In the peroxide curable silicone pressure-sensitive adhesive used in the present invention, radicals generated from the organic peroxide draw hydrogen of Si-CH ₃ groups of the silicone rubber, and the generated SiCH ₂ radicals are bonded to each other. The crosslinking reaction proceeds.
When an addition-reaction type silicone adhesive is used, for example, compounds such as amine compounds, organic tin compounds, organic sulfur compounds, phosphorus compounds, and organic peroxides are included in the material that the adhesive such as the substrate or primer comes into contact with. If this is the case, it will cause curing inhibition due to the catalyst poison for the platinum-based catalyst that is always used, and it turns out that “residue residue (removability)” cannot be solved in the above problems. did.
Therefore, in the present invention, it is essential to use a peroxide-curing type silicone-based pressure-sensitive adhesive, and the pressure-sensitive adhesive layer is applied to the base sheet through the primer layer containing the above compound. The present invention is effective when it is applied or when the above-mentioned compound is contained in the substrate sheet. In the present invention, the primer layer is formed for the purpose of improving the weather resistance of the base material and the pressure-sensitive adhesive layer and improving the adhesion between the base material and the pressure-sensitive adhesive layer. The primer layer has a weather resistance such as an ultraviolet absorber or a light stabilizer. Auxiliaries can be included.
As UV absorbers, benzophenone, benzotriazole,
A triazine-based or cyanoacrylate-based one or a polymer type ultraviolet absorber obtained by polymerizing a (meth) acryloyl group present in these side chains can be contained.
As the light stabilizer, a hindered amine-based HALS or a hindered phenol-based one can be contained.
Incidentally, in addition to hindered amine light stabilizers, amine compounds react with triazine ultraviolet absorbers, cyanoacrylate ultraviolet absorbers, benzotriazole ultraviolet absorbers, melamine flame retardants, polyurethane adhesives, etc., and organotin compounds react. The organic sulfur compound is derived from the sulfur heat-resistant stabilizer and the like, and the organic peroxide is derived from the radical initiator and the like.

Peroxide-curing silicone adhesives are (1) diorganopolysiloxanes such as polydimethylsiloxane and (2) silicone resins that are polyorganosiloxanes containing trifunctional or tetrafunctional siloxane units in the molecule. In the crosslinking reaction, radicals generated by organic peroxides such as benzoyl peroxide (1) extracted Si-CH ₃ group hydrogen in diorganopolysiloxane and formed Si. It is a pressure-sensitive adhesive that proceeds by bonding —CH ₂ .
Commercially available peroxide-curing silicone pressure sensitive adhesives include GE Toshiba Silicone YR3340, Toray Dow Corning SE4200, SH4280, Shin-Etsu Chemical KR-100, KR-101-10 (toluene) Solvent type), KR-120, KR-130, and X-40-3287 (isoparaffin solvent type).

As the peroxide, an organic peroxide is used. Examples of organic peroxides include benzoyl peroxides (t-butylbenzoate peroxide, 2,5-dimethyl-2,5-diperoxybenzoylhexane, dibenzoyl peroxide, 4,4′-dimethyldibenzoyl peroxide. 3,3′-dimethyldibenzoyl peroxide, 2,2′-dimethyldibenzoyl peroxide, 2,2 ′, 4,4′-tetrachlorodibenzoyl peroxide, 2,4-dichlorobenzoyl peroxide), Cumyl peroxide, t-butyl cumyl peroxide, t-butyl peroxide, t-butyl isobutyrate peroxide, t-butyl-2-ethylhexanoate peroxide, 2,2-bis t-butyloctane peroxide, Examples include 1,1-bis peroxide t-butylcyclohexane.
Benzoyl peroxides are preferably used from the viewpoint that the adhesive properties can be adjusted by changing the addition amount.

  The usage-amount of an organic peroxide is 0.01-10 mass parts normally with respect to 100 mass parts of peroxide hardening type silicone adhesives, Preferably, it is 0.1-5 mass parts. By setting it as 0.01 mass part or more, desired adhesive force is obtained, and setting it as 10 mass parts or less prevents that hardening reaction advances too much and desired adhesive force is no longer obtained.

  The above peroxide-curing silicone pressure-sensitive adhesive is usually marketed as an organic solvent solution of about 30 to 70% by weight such as hexane-like paraffinic or aromatic-like toluene. The organic peroxide is dissolved so as to have the concentration as described above and used as a coating solution.

In order to form the pressure-sensitive adhesive layer, the coating liquid is applied to the release agent layer of the release sheet (the release sheet will be briefly described in the following paragraph), the solvent is evaporated, and the adhesive layer is heated and cured. Then, it may be transferred to the base sheet by laminating it, or the coating liquid is directly applied to the base sheet to evaporate the solvent, followed by heat curing to form an adhesive layer, and then peeling. Sheets may be bonded together. Furthermore, an adhesive may be applied to one side of the base sheet and a release agent may be applied to the other side. When a pressure-sensitive adhesive is applied to one side of the substrate sheet and a release agent is applied to the other side, the re-peelable pressure-sensitive adhesive sheet is used in a form wound in a laminate or a roll.
Heat curing is usually performed at about 130 to 200 ° C., preferably 140 to 180 ° C. for 1 to 15 minutes, preferably about 3 to 7 minutes.
By heating at 130 ° C. or higher, the adhesive strength due to insufficient curing is prevented from becoming insufficient, and by heating at 200 ° C. or lower, heat shrinkage occurs in the base sheet, or deterioration or discoloration occurs. Can be prevented.

As the base sheet, polyethylene terephthalate sheet, polyethylene naphthalate sheet, polybutylene terephthalate sheet, polyimide sheet, polyetherimide sheet, polyaramid sheet, polyether ketone sheet, polyether ether ketone sheet, polyphenylene sulfide sheet, poly ( 4-methylpentene-1) sheets, polyolefin sheets having heat resistance, or sheets added with other resins or additives for imparting heat resistance to these, etc. are used, but heat resistance, dimensional stability, economic efficiency From this viewpoint, a polyethylene terephthalate sheet is preferable.
The thickness of the base sheet varies somewhat depending on the material used, but is usually about 5 to 300 μm, and preferably about 10 to 100 μm. In the case of a polyethylene terephthalate sheet which is one of the preferred base sheets, the thickness is preferably about 10 to 50 μm.
Various additives added to the primer layer as described above may be added to the base material sheet. In the re-peelable pressure-sensitive adhesive sheet of the present invention using a peroxide-curable silicone pressure-sensitive adhesive, They are not adversely affected by these additives.
Examples of the polyethylene terephthalate sheet or film to which the ultraviolet absorber is added include PET25 Q37 manufactured by Toray Industries, Inc. and Tetron film HB manufactured by Teijin DuPont Films. Moreover, you may apply | coat the primer to which the above ultraviolet absorbers were added with respect to the base material sheet | seat which has not added the ultraviolet absorber like Toray Co., Ltd. PET25 T60.

  To apply the adhesive to the release sheet or base sheet, the usual gravure coating method, bar coating method, spray coating method, spin coating method, roll coating method, die coating method, knife coating method, air knife coating Method, curtain coating method, etc.

  The thickness of the pressure-sensitive adhesive layer formed on the release sheet or base sheet after drying is usually about 1 to 50 μm, preferably about 5 to 40 μm. By setting the thickness of the pressure-sensitive adhesive layer to 1 μm or more, it is possible to ensure the adhesive force and cohesive force (holding force) required for the re-peelable pressure-sensitive adhesive sheet for protecting the coating film, and by setting it to 50 μm or less. In addition to preventing cost increase, the adhesive layer is prevented from protruding from the end.

  From the viewpoint of preventing the “glue residue” phenomenon in which a part of the adhesive layer moves to the coating film when the re-peelable pressure-sensitive adhesive sheet of the present invention is peeled off from the painted surface of the car body or parts of the automobile, In order to enhance adhesion to the base sheet, corona discharge treatment and / or ozone is applied to the base sheet before bonding the base sheet to the adhesive layer surface applied to the release sheet or before applying the adhesive. It is preferable to process.

  As a release sheet for protecting the adhesive layer, a fluororesin, a silicone resin, a resin film such as polyethylene terephthalate, polyethylene, and polypropylene coated with a release agent such as a long chain alkyl group-containing carbamate, fine paper, glassine paper, A release sheet obtained by coating the release agent on a paper substrate such as laminate paper can be used. The thickness of the release sheet varies somewhat depending on the material used, but is usually 10 to 250 μm, preferably 20 to 200 μm. The thickness of the release agent layer is usually about 0.1 to 5 μm, preferably about 0.5 to 2 μm.

The present invention also provides a method for protecting a coating film, characterized in that the re-peelable pressure-sensitive adhesive sheet is attached to an incompletely cured coating film.
The adherend to which the coating film protection method of the present invention is applied is incompletely formed with plastics, in particular, plastic bumpers for automobiles and plastic parts for home appliances, usually formed with urethane-based paints. It is a cured coating film.
Since the coating film formed on the surface of these plastics cannot be cured at high temperatures like the coating film formed on the metal surface from the viewpoint of heat resistance, the curing is usually incomplete or in the coating film. A trace amount of solvent remains.
In this way, when the conventional re-peelable pressure-sensitive adhesive sheet is applied to a coating film in which curing is incomplete or a trace amount of solvent remains, and after leaving for a long period of time, the used sheet is peeled off. As described above, problems such as “stepping”, “white blur”, and “glue residue” occur. If the re-peelable pressure-sensitive adhesive sheet of the present invention is used, the coating film can be protected without any such problems.

  EXAMPLES Next, although an Example and a comparative example demonstrate this invention further in detail, this invention is not limited at all by these examples.

[Example 1]
A 25 μm thick polyethylene terephthalate film “PET25T70 manufactured by Toray Industries, Inc.” is used as a substrate sheet for the releasable adhesive sheet, and a 38 μm thick polyethylene terephthalate film coated with a fluororesin [Lintec SP-PET38YSD] manufactured by the same company was used.
SE4200 manufactured by Toray Dow Corning Co., Ltd., which is a peroxide curable silicone pressure-sensitive adhesive (having a methyl group as a reactive site and a mixed skeleton derived from polydimethylsiloxane and resin as a basic skeleton. Solid content 60 (Mass% toluene solution) A solution in which a mixture of 100 parts by mass and 0.6 parts by mass of benzoyl peroxide was dissolved in 100 parts by mass of toluene was used.
The above solution was coated on the surface of the base sheet using a knife coating method so that the thickness after drying was 30 μm, preliminarily dried at 90 ° C. for 2 minutes, and then heated and dried at 150 ° C. for 5 minutes. .
Then, the releasable pressure-sensitive adhesive sheet of the present invention was produced by pasting together with the fluororesin-coated surface of the release sheet.

[Example 2]
Except for using a polyethylene terephthalate film [PET25 Q37 manufactured by Toray Industries, Inc.] with a thickness of 25 μm containing Tinuvin P (manufactured by Ciba Specialty Chemicals, Inc.), which is a benzotriazole-based UV absorber, as a base sheet. It carried out similarly to Example 1 and produced the releasable adhesive sheet of this invention.

Example 3
A polyethylene terephthalate film “PET25T70 manufactured by Toray Industries, Inc.” having a thickness of 25 μm was used as a base sheet for the re-peelable pressure-sensitive adhesive sheet. On this base sheet, 10 parts by mass of a benzotriazole UV absorber (Tinuvin P) and 100 parts by mass of a methyl acrylate-ethyl acrylate copolymer (methyl acrylate / ethyl acrylate molar ratio 9/1) were dissolved in toluene. Then, a solution (primer) prepared so as to have a solid content of 10% by mass was coated with a Mayer bar coat so as to have a dry thickness of 5 μm.
The same adhesive as that used in Example 1 was applied to the coated surface after drying, an adhesive layer was formed in the same manner as in Example 1, and the same release sheet as that used in Example 1 was used as the adhesive. The re-peelable pressure-sensitive adhesive sheet of the present invention was prepared by sticking to the layer.

Example 4
Methyl silicone adhesive YR3340 manufactured by GE Toshiba Silicones Co., Ltd., which is a peroxide-curing silicone adhesive (having a methyl group as a reactive site and having a mixed skeleton derived from polydimethylsiloxane and resin as a basic skeleton) This was carried out in the same manner as in Example 1 except that a solution prepared by dissolving 100 parts by mass of a toluene solution having a solid content of 40% by mass and 0.8 parts by mass of benzoyl peroxide in 100 parts by mass of toluene was used. A re-peelable pressure-sensitive adhesive sheet was prepared.

Example 5
A polyethylene terephthalate film [PET25 Q37 manufactured by Toray Industries, Inc.] with a thickness of 25 μm containing a benzotriazole-based ultraviolet absorber (Tinuvin P) was prepared as a base sheet for a re-peelable pressure-sensitive adhesive sheet. A solution obtained by dissolving fluorosilicone (X-70-201) manufactured by Co., Ltd. in toluene so as to be 2% by mass was applied using a bar coater, and heat-cured at 150 ° C. for 2 minutes. A release layer of 0.0 μm was formed.
Next, the same pressure-sensitive adhesive as in Example 1 is applied to the surface of the sheet opposite to the release agent layer to form a pressure-sensitive adhesive layer under the same conditions as in Example 1, and wound around a paper tube. A re-peelable pressure-sensitive adhesive sheet was prepared.

[Comparative Example 1]
A polyethylene terephthalate film with a thickness of 25 μm, which is a 25 μm thick polyethylene terephthalate film “PET25T70, manufactured by Toray Industries, Inc.” and a fluororesin-coated polyethylene terephthalate film as a release sheet, is used as a base sheet for a re-peelable adhesive sheet for comparison. “SP-PET38YSD manufactured by Lintec Corporation” was used.
100 parts by mass of an acrylic pressure-sensitive adhesive obtained by diluting a butyl acrylate-2-ethylhexyl acrylate-acrylic acid copolymer (molar ratio: 5/4/1) having a polymerization average molecular weight of 600,000 as an adhesive with 30% by mass of ethyl acetate, A solution prepared by mixing 5 parts by mass of a 5 part by mass ethyl acetate solution of 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane was used as a crosslinking agent. The solution was applied to the surface of the base sheet using a knife coating method so that the thickness after drying was 30 μm, and heat-dried at 90 ° C. for 2 minutes. Then, it bonded with the fluororesin surface of the said peeling sheet, and created the adhesive sheet for a comparison.

[Comparative Example 2]
A polyethylene terephthalate film “PET25T70 manufactured by Toray Industries, Inc.” having a thickness of 25 μm was used as the base sheet. To improve the weather resistance, 10 parts by mass of benzotriazole UV absorber Tinuvin P is mixed with 100 parts by mass of methyl acrylate / ethyl acrylate copolymer (molar ratio 9/1) on the base material, and 10% The coating solution diluted with toluene was applied with a Mayer bar coat to a dry thickness of 5 μm.
Addition-type silicone-based adhesive “SD-4585PSA (addition-reactive silicone containing a cross-linking agent) 100 parts by mass produced by Toray Dow Corning Co., Ltd., platinum-based curing catalyst produced by Toray Dow Corning Co., Ltd. A solution obtained by diluting a mixed solution consisting of 1 part by mass of SRX-212 with 100 parts by mass of toluene was used.
The pressure-sensitive adhesive was applied to the coated surface of the base material sheet using a knife coating method so that the thickness after drying was 30 μm, and heat-dried at 130 ° C. for 2 minutes. Subsequently, it was bonded to the fluororesin-coated surface of the release sheet to prepare a comparative adhesive sheet.

  The following tests were conducted using the re-peelable pressure-sensitive adhesive sheets of the present invention and comparative re-peelable pressure-sensitive adhesive sheets obtained in the above Examples and Comparative Examples, and the results obtained are shown in Table 1.

<Evaluation items and evaluation methods>
Two-component polyurethane topcoat paint for automobiles (100 parts by weight of Quartz Clear Z, manufactured by Kansai Paint Co., Ltd.) and 40 parts by weight of multi-curing agent on polyolefin thermoplastic elastomer plate coated with electrodeposition primer and intermediate coating Were mixed so that the thickness after drying was 20 μm, dried at 60 ° C. for 30 minutes, and then allowed to stand at room temperature for 30 minutes to form an incompletely cured coating film.
Next, the re-peelable pressure-sensitive adhesive sheet obtained in each example was affixed to the incompletely cured coating film, and after standing for 24 hours at room temperature, the state of the coating film immediately after peeling was visually observed. Each characteristic was measured using [Surface shape analyzer SURFTEST SV-3000 manufactured by Mitutoyo Corporation] and evaluated according to the following criteria.
(1) Step of wrinkle portion ○: A step cannot be confirmed.
X: A level | step difference can be confirmed and the level difference of a level | step difference is more than 1 micrometer.
(2) Boundary between sheet pasting part and non-sticking part ○: The boundary cannot be confirmed.
X: A boundary can be clearly confirmed.
(3) White blur on glue contact surface ○: White blur cannot be confirmed.
X: White blur can be confirmed, and can be confirmed after being left outdoors for one week.
(4) Adhesive residue (removability)
○: No adhesive residue can be confirmed on the painted surface.
X: Adhesive residue on the coated surface is remarkable, peeling is heavy, and peeling is not easy.

  As is clear from Table 1, it can be seen that the re-peelable pressure-sensitive adhesive sheet of the present invention obtained in the examples is superior to that of the re-peelable pressure-sensitive adhesive sheet obtained in the comparative example with respect to any property.

Claims (9)

  A re-peelable pressure-sensitive adhesive sheet for an incompletely cured coating film provided with a pressure-sensitive adhesive layer on a base sheet, wherein the pressure-sensitive adhesive layer is made of a peroxide-curable silicone pressure-sensitive adhesive. Mold adhesive sheet.   The re-peelable pressure-sensitive adhesive sheet according to claim 1, wherein the peroxide-curable silicone pressure-sensitive adhesive further contains a curing agent.   The re-peelable pressure-sensitive adhesive sheet according to claim 2, wherein the curing agent is benzoyl peroxide.   The re-peelable pressure-sensitive adhesive sheet according to claim 1, wherein the base sheet is a polyethylene terephthalate sheet.   The re-peelable pressure-sensitive adhesive sheet according to claim 4, wherein the polyethylene terephthalate sheet contains a weather resistance assistant.   The re-peelable pressure-sensitive adhesive sheet according to any one of claims 1 to 5, wherein the pressure-sensitive adhesive layer is provided on a substrate sheet via a primer layer.   The re-peelable pressure-sensitive adhesive sheet according to any one of claims 1 to 6, which is a protective sheet for resin products.   The re-peelable pressure-sensitive adhesive sheet according to any one of claims 1 to 7, which is wound in a roll shape.   A method for protecting a coating film, comprising: attaching a re-peelable pressure-sensitive adhesive sheet provided with a pressure-sensitive adhesive layer made of a peroxide-curable silicone pressure-sensitive adhesive to a base sheet to an incompletely cured coating film.