JPH07179826A - Pressure-sensitive sheet for mending fluororesin film - Google Patents

Abstract

PURPOSE:To prepare a pressure-sensitive sheet which has sufficient adhesion to a fluororesin film and excellent weatherability by continuously laminating a pressure-sensitive silicone adhesive to at least one side of a fluororesin film. CONSTITUTION:This sheet is obtained by continuously laminating a pressure- sensitive silicone adhesive to at least one side of a fluororesin film base. Examples of the adhesive include a condensation curing pressure-sensitive silicone adhesive comprising as major components a raw dimethylpolysiloxane rubber blocked with a silanol group at each end and a polysiloxane resin (a) comprising trimethylsiloxy units and SiO4/2 units, and an addition curing pressure-sensitive silicone adhesive comprising as major components a raw dimethylpolysiloxane rubber blocked with a dimethylvinylsiloxy group at each end, the resin (a), and an organopolysiloxane containing Si-bonded hydrogen atoms.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a pressure-sensitive adhesive sheet for repairing a fluororesin film.

[0002]

2. Description of the Related Art Fluororesin films are excellent in weather resistance, heat resistance and releasability, so
Garden house, pipe lining, tank lining,
Widely used in applications such as optical fiber coatings and wire coatings.

[0003]

However, this type of fluororesin film has a problem that the pressure-sensitive adhesive sheet for repair does not adhere to its surface because of its excellent releasability. When a synthetic resin film such as polyester resin is used as the base of the adhesive sheet for repair,
There has been a problem that the repaired portion is contaminated or deteriorates with time, impairing the original characteristics of the fluororesin film. The present inventor has arrived at the present invention as a result of intensive research to solve the above problems. An object of the present invention is to provide a repairing pressure-sensitive adhesive sheet that can be suitably used as a repairing sheet for a fluororesin film because it has sufficient adhesive strength to the fluororesin film and has excellent weather resistance. It is in.

[0004]

[Means for Solving the Problems and Its Action] The above-mentioned object is characterized in that a silicone adhesive is continuously laminated on at least one surface of a fluororesin film substrate, and an adhesive sheet for repairing a fluororesin film is provided. Achieved by

To explain this, the fluororesin film substrate used in the present invention may be made of a fluororesin in the form of a film, and the kind and shape thereof are not particularly limited, but repair It is preferable that the film is the same as the fluororesin film to be used or a film made of the same kind of fluororesin as the fluororesin film to be repaired. Examples of the fluororesin constituting the fluororesin film substrate include polytetrafluoroethylene resin (PTFE resin), perfluoroalkoxy resin (PFA resin), fluorinated ethylene propylene resin (FEP resin) and the like. The silicone pressure-sensitive adhesive used in the present invention is generally called a silicone pressure-sensitive adhesive or a silicone pressure-sensitive adhesive, and its type is not particularly limited.
As such a silicone adhesive, a condensation reaction cure in which a polysiloxane resin composed of a dimethylpolysiloxane raw rubber capped with silanol groups at both ends and a trimethylsiloxy unit and a SiO _4/2 unit is a main component and cured by a condensation reaction in the presence of an organotin compound Type silicone adhesive, silanol-terminated dimethylsiloxane / methylvinylsiloxane copolymer raw rubber, and organic peroxide-curable silicone adhesive containing the above polysiloxane resin as a main component and curing in the presence of an organic peroxide, both Mainly dimethylpolysiloxane raw rubber blocked with dimethylvinylsiloxy groups at the ends or dimethylsiloxane-methylvinylsiloxane copolymer raw rubber blocked with dimethylvinylsiloxy groups at both ends, the above polysiloxane resin and silicon-bonded hydrogen atom-containing organopolysiloxane As a component, there is an addition reaction-curable silicone pressure-sensitive adhesive that cures by an addition reaction in the presence of a platinum-based catalyst. Among these, in the present invention, an organic peroxide-curable silicone pressure-sensitive adhesive and an addition reaction-curable silicone pressure-sensitive adhesive are preferable, and an addition-reaction-curable silicone pressure-sensitive adhesive is particularly preferable.

The pressure-sensitive adhesive sheet of the present invention is a sheet obtained by continuously laminating the above-mentioned silicone pressure-sensitive adhesive on at least one side of the above-mentioned fluororesin film substrate, and the silicone-pressure-sensitive adhesive only on one side of the fluororesin film substrate. The agent may be laminated, or the silicone adhesive may be laminated on both surfaces of the fluororesin film substrate. here,
The continuous lamination of the silicone pressure-sensitive adhesive means a state in which the above-mentioned silicone pressure-sensitive adhesives are continuously connected and laminated. Occurs. Here, as a method of laminating the silicone adhesive, a conventionally known method such as a metering bar method, a reverse method, an air knife method can be used.

The pressure-sensitive adhesive sheet of the present invention will be described below with reference to the drawings. 1 and 2 are sectional views of the pressure-sensitive adhesive sheet of the present invention, in which 1 is a fluororesin film substrate and 2 is a silicone pressure-sensitive adhesive. In FIG. 1, a silicone adhesive 2 is laminated on one side of a fluororesin film substrate 1, and the silicone adhesive 2 is continuously laminated. Further, in FIG. 2, the silicone adhesive 2 is laminated on both sides of the fluororesin film substrate 1, and the silicone adhesive 2 is continuously laminated. Here, the thickness of the silicone pressure-sensitive adhesive layer is generally 0.5 to 100 μm.
And the range of 5 to 50 μm is preferable.

In the pressure-sensitive adhesive sheet for repairing a fluororesin film of the present invention as described above, since the silicone pressure-sensitive adhesive surface has sufficient adhesive strength to the fluororesin film and is excellent in weather resistance, It is extremely useful as an adhesive sheet for repairing resin films.

[0009]

EXAMPLES The present invention will now be described in more detail by way of examples. In the examples, "parts" means "parts by weight".

[0010]

Example 1 30 parts by weight of dimethylpolysiloxane raw rubber having both ends of a molecular chain blocked with silanol groups and (CH ₃ ) ₃
30 parts by weight of a polysiloxane resin _{composed of} SiO _1/2 units and SiO _4/2 units and having a molar ratio of 1: 1 were mixed with 40 parts by weight of toluene. To 100 parts by weight of this mixture, 1 part by weight of benzoyl peroxide was added and uniformly mixed to prepare a silicone pressure-sensitive adhesive composition. Next, this silicone pressure-sensitive adhesive composition was applied to the surface of a polytetrafluoroethylene resin film substrate (thickness 50 μm) in such an amount that the coating film thickness became 50 μm. After the toluene was volatilized with cold air, the silicone pressure-sensitive adhesive composition was cured by heating at 150 ° C. for 5 minutes. The obtained silicone pressure-sensitive adhesive laminate sheet was attached to the same polytetrafluoroethylene resin film (thickness 50 μm) as above to prepare a test body. Put this test piece in the sunshine weather meter and set it to 1.0
An exposure test of 00 hours was performed. After 1,000 hours, the test piece was taken out, and after bending the test piece, it was tried to peel off the silicone adhesive laminated sheet, but the silicone adhesive laminated sheet adhered to the polytetrafluoroethylene resin film. , I couldn't pull it off easily. When the adhesive strength at this time was measured, the value was
It was 1.4 kg / inch. For comparison, in the above,
A silicone pressure-sensitive adhesive laminated sheet was obtained in the same manner as above except that a polyester resin film [trade name: Lumirror S-10 manufactured by Toray Industries, Inc.] was used in place of the polytetrafluoroethylene resin film substrate of the silicone pressure-sensitive adhesive laminated sheet. Created. Then, using this silicone pressure-sensitive adhesive laminated sheet, a test body was prepared in the same manner as above. When the characteristics of this test body were measured in the same manner as described above, the test body after the 1,000-hour exposure test with a weather meter had cracks when it was bent. For comparison, instead of the silicone adhesive composition in the above, an acrylic rubber adhesive [Toyo Ink Co., Ltd.
Acrylic rubber-based pressure-sensitive adhesive laminated sheet was prepared in the same manner as described above except that the product name, BPS2411], was used. Next, using this acrylic rubber-based pressure-sensitive adhesive laminated sheet, a test body was prepared in the same manner as above. When the characteristics of this test body were measured in the same manner as above, the acrylic rubber-based pressure-sensitive adhesive laminated sheet was peeled off from the polytetrafluoroethylene resin film in the test body after the 1,000-hour exposure test with a weather meter. Was.

[0011]

Example 2 A polysiloxane composed of (CH ₃ ) ₃ SiO _1/2 units and SiO _4/2 units with a molar ratio of 0.7: 1.0 and a silanol group content of 0.5% by weight. Resin 55
Parts, both ends dimethylvinylsiloxy group blocked dimethylpolysiloxane raw rubber (vinyl group content 0.02% by weight) 4
5 parts, viscosity at 25 ° C., 20 centipoise, both ends trimethylsiloxy group-blocked methylhydrogenpolysiloxane (silicon atom-bonded hydrogen atom content 1.6% by weight)
0.2 parts were mixed. In this mixture, the molar ratio of silicon-bonded hydrogen atoms and vinyl groups was 9: 6. Next, 3-methyl-1 was added to this mixture as an addition reaction inhibitor.
0.2 parts of butyn-3-ol were added and dissolved in 150 parts of toluene. Then, a complex catalyst of chloroplatinic acid and divinyltetramethyldisiloxane was added thereto in an amount such that the platinum metal was 100 ppm with respect to the total amount of the above polysiloxane, and mixed to give a silicone adhesive having a nonvolatile content of 40% by weight. An agent composition was obtained. Next, this silicone pressure-sensitive adhesive composition was applied on the surface of the polytetrafluoroethylene resin film substrate (thickness 50 μm) in such an amount that the coating film thickness became 50 μm. Then, the silicone pressure-sensitive adhesive composition was cured by heating at 150 ° C. for 5 minutes. The obtained silicone pressure-sensitive adhesive laminate sheet was attached to the same polytetrafluoroethylene resin film (thickness 50 μm) as above to prepare a test body. This test body was placed in a sunshine weather meter and an exposure test was performed for 1,000 hours. After 1,000 hours, the test piece was taken out, and after bending the test piece, it was tried to peel off the silicone adhesive laminated sheet, but the silicone adhesive laminated sheet adhered to the polytetrafluoroethylene resin film. , I couldn't pull it off easily. When the adhesive strength at this time was measured, the value was 1.5 kg / inch.

[0012]

The pressure-sensitive adhesive sheet for repairing a fluororesin film according to the present invention has a silicone pressure-sensitive adhesive continuously laminated on at least one side of a fluororesin film substrate.
It has a feature that it has a sufficient adhesive force to a fluororesin film and is excellent in weather resistance.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a pressure-sensitive adhesive sheet for repair of the present invention, in which a silicone pressure-sensitive adhesive 2 is continuously laminated on one surface of a fluororesin film substrate 1.

FIG. 2 is a cross-sectional view of a pressure-sensitive adhesive sheet for repair of the present invention, in which a silicone pressure-sensitive adhesive 2 is continuously laminated on both sides of a fluororesin film substrate 1.

[Explanation of symbols]

 1 Fluororesin film base 2 Silicone adhesive

Claims (1)

[Claims] 1. A pressure-sensitive adhesive sheet for repairing a fluororesin film, wherein a silicone pressure-sensitive adhesive is continuously laminated on at least one surface of a fluororesin film substrate.