JPH0457875A - Preparation of heat-resistant conductive tape with conductive pressure-sensitive adhesive - Google Patents

Abstract

PURPOSE:To obtain a heat-resistant conductive tape with a conductive pressure- sensitive adhesive, the support of which suffers no deterioration due to oxidation by coating a heat-resistant release liner with a specific conductive pressure- sensitive adhesive, crosslinking the adhesive by heating, and transferring the crosslinked conductive pressure-sensitive adhesive layer to the conductive support. CONSTITUTION:A release liner coated with a methyl silicone resin is coated with a conductive pressure-sensitive adhesive formed by blending a methylphenyl- copolymerized silicone resin with a conductive filler to obtain a conductive pressure-sensitive adhesive layer. The adhesive layer is crosslinked by heating and then transferred to a conductive support. The conductive filler may include powder of metals such as silver, nickel, copper, indium, tin or solder, and powder of carbon or graphite. The conductive support may include metallic foil including that of copper, aluminum or iron.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for manufacturing a heat-resistant conductive tape with a conductive pressure-sensitive adhesive, and more specifically, it relates to a method for manufacturing a heat-resistant conductive tape with a conductive pressure-sensitive adhesive. It is used for shielding leakage electromagnetic waves, for grounding to prevent static electricity, and for lead cables for surface heating elements and electroplating.When pasted together, the tape has a conductive effect, which increases the grounding effect. The present invention relates to a method for manufacturing a heat-resistant conductive tape that can be used in environments that require high and low temperatures and chemical resistance.

[Conventional technology]

Conventional conductive tapes with conductive pressure-sensitive adhesives use acrylic resin, a blend of acrylic resin with rosin, or rubber-based materials such as natural rubber, NBR, or butyl rubber as the adhesive component of the conductive pressure-sensitive adhesive. is used.

These conductive pressure-sensitive adhesives can be crosslinked at temperatures below 100°C that do not oxidize the conductive support, so they can be applied directly to a conductive support such as metal foil and heated together with the conductive support. A conductive tape with a conductive pressure-sensitive adhesive is produced by crosslinking the conductive pressure-sensitive adhesive layer.

[Problem that the invention seeks to solve]

These conventional conductive pressure-sensitive adhesives can be used in high-temperature environments up to a temperature of 80 to 120° C. At higher temperatures, the adhesive layer softens and the adhesive strength decreases significantly. Of course, it is impossible to use it at such high temperatures, but
The tape may later fail when exposed to such high temperature conditions. For example, if the tape is later applied through a soldering bath process, the adhesive layer of the tape will soften, causing the tape to become misaligned or the attached parts to fall off. In addition, when joining a cable to a metal that cannot be soldered, it is possible to attach a metal foil tape with conductive pressure-sensitive adhesive to the metal surface that cannot be soldered, and then solder the cable to it for grounding. However, acrylic adhesives cannot withstand the high temperatures of solder and may peel off along with the tape, making it impossible to perform grounding processes.

Furthermore, the usable temperature of acrylic pressure-sensitive adhesives in low-temperature environments is 0 to -5°C for rosin-blended quality adhesives, and about -30°C for pure acrylic adhesives. It can withstand this temperature when pasted, but
Processing and inventory of tape at such low temperatures is
This is not possible due to decreased adhesive strength.

Furthermore, conventional pressure sensitive adhesives have poor water resistance, humidity resistance, and chemical resistance, so they cannot be used in high humidity environments or immersed in water, hot water, or chemicals such as those used during plating. The adhesion properties of these pressure-sensitive adhesives were originally only 1000 to 1200 grams/25 cm width, but when a conductive filler was added to make them conductive, this The adhesive strength of the seed conductive tape decreased from 800 to 900 grams/25 am width, making it difficult to adhere.

Further, in order to solve this problem, when a heat-resistant resin is used as the adhesive, the temperature required to promote crosslinking of the resin needs to be high. This adhesive is applied to metal foil made of copper, aluminum, or iron that is easily oxidized by heat, or to a film whose surface has been treated with a metal thin film, and then passed through a high-temperature crosslinking process. The electrostatic support is oxidized by high-temperature heat, resulting in discoloration and decreased conductivity.

[Means for solving problems]

In view of the above circumstances, the inventors of the present invention have conducted intensive research to obtain a heat-resistant conductive tape that solves the above-mentioned problems. When a copolymerized silicone resin is used as an adhesive, as in the past, if this adhesive is applied directly to a conductive support and the adhesive is heated at the same time, the crosslinking temperature of the silicone resin is high. , oxidizes the conductive support. Therefore, in order to prevent the oxidation of the conductive support due to high temperatures during crosslinking of the methylphenyl copolymerized silicone resin adhesive, the present invention first applies a conductive pressure-sensitive adhesive to a heat-resistant release liner, and then cross-links it by heating. After that, the crosslinked conductive pressure-sensitive adhesive layer is transferred to a conductive support to complete a heat-resistant conductive tape with a conductive pressure-sensitive adhesive that does not deteriorate due to oxidation on the support.

That is, the present invention heat-crosslinks a conductive pressure-sensitive adhesive layer obtained by applying a conductive pressure-sensitive adhesive containing a conductive filler to a methylphenyl copolymer silicone resin to a release liner coated with a methyl-based silicone resin. This is a method for producing a heat-resistant conductive tape with a conductive pressure-sensitive adhesive, which is characterized in that the tape is then transferred to a conductive support.

In the present invention, glassine paper coated with methyl-based silicone resin or a heat-resistant inner layer of a heat-resistant film is coated with metal powder such as silver powder, nickel powder, copper powder, solder powder, or carbon powder on methylphenyl copolymer silicone resin. A conductive pressure-sensitive adhesive containing conductive filler such as powder is applied, and after cross-linking by heating at 100 to 170°C, a metal foil made of copper, aluminum, or iron, or a synthetic resin that is also insulating is applied. A heat-resistant conductive tape with a conductive pressure-sensitive adhesive is obtained by transferring the conductive pressure-sensitive adhesive layer to a conductive support that has been metallized such as a sheet or a film by metal vapor deposition.

The release liner used in the present invention is suitably a release liner coated with a methyl-based silicone resin, which is heat-resistant and is coated on glassine paper or a film that is dimensionally stable by heat.

Further, in the conductive pressure-sensitive adhesive used in the present invention, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, aminosilane, lead or tin octoate (lead or tin octylate), or the like can be used as a crosslinking catalyst.

The conductive filler used in the present invention has its particle shape, particle size, and content in accordance with the thickness of the conductive adhesive layer applied to the conductive support such as metal foil, from 10 to 80 micrometers. Establish. The types of metal powder used for conductive fillers include silver, nickel, copper, indicium, tin, and solder (alloy of lead and tin), and the particle shape is mainly dendritic or round, and the particle size ranges from 2 to 2. It is 90 micron meter. In addition to metal powder, carbon powder and graphite are used, either singly or as a mixture of multiple types. As a condition for selecting metal powder, avoid using metal types that have a large difference in ionization tendency and have a high possibility of causing electrical corrosion with the metal type used for the support. The content of the conductive filler in the adhesive is preferably 3 to 70% by weight.

The conductive tape manufactured in this way can withstand use when pasted or pasted in high- or low-temperature environments. By forming a conductor, it is possible to perform functions such as preventing leakage of electromagnetic waves. In addition, in order to supply electricity to such a large number of seedlings, this heat-resistant conductive tape with a conductive pressure-sensitive adhesive has the advantage of omitting the conventionally time-consuming and time-consuming soldering process.

〔Example〕

Next, the present invention will be explained with reference to Examples and Comparative Examples.

(Preparation of electrically conductive pressure-sensitive adhesive) Methylphenyl copolymerized silicone resin 80 parts by weight (PSA6574 manufactured by Toshiba Silicone Co., Ltd.) Nickel powder
20 parts by weight (5F300 manufactured by Kashi Metal Foil & Powder Industry Co., Ltd.), a small amount of benzoyl peroxide (BPO paste manufactured by Sansho Kako Co., Ltd.), and 30 parts by weight of solvent (toluene/xylene-1,1) were uniformly mixed and dispersed using a dispersion machine. A conductive pressure-sensitive adhesive of the present invention was prepared.

(Formation of heat-resistant conductive tape with conductive pressure-sensitive adhesive) Methyl silicone resin (X556 manufactured by Toshiba Silicone Co., Ltd.)
-701) and the solvent n-hexane at a dilution ratio of 300% by weight was applied on glassine paper so that there were no pinholes in the dried film, and the mixture was heated at 160°C for 1 hour.
The conductive pressure-sensitive adhesive described above was applied to the release liner, which had been cured for 5 seconds to form a dry film of 3 to 20 μm, in a thickness of 100 μm using a Comma Reverse coating machine. Next, the solvent contained in this adhesive is evaporated in a preheating process at 90°C for 2 minutes, and then heated at 165°C for 3 minutes to form a crosslinked conductive pressure sensitive adhesive on the release liner. did. After that, the adhesive layer was transferred to a copper foil with a thickness of 35 μm at a pressure of 2 Kgf, and the crosslinking was completed by storing it at room temperature for 3 days. I made a tape.

Next, the tape produced above and the metal foil tape with acrylic conductive pressure-sensitive adhesive that had already been applied were cut into strips with a width of 25 mm, and the DC electrical resistivity and adhesive strength were measured. A comparison was made and the results are shown in Table 1.

Table 1 *Electrical conductivity: DC electrical resistivity in the thickness direction of the tape under a load of 2 kg *Based on the test method of Adhesive Crab JIS Z-0237.

〔Effect of the invention〕

The heat-resistant conductive tape with a conductive pressure-sensitive adhesive obtained by the manufacturing method of the present invention can be obtained without discoloration due to oxidation or deterioration of conductivity due to high temperature on a conductive support such as silver foil or aluminum foil. When this tape is used for EMI shielding of signal cables of facsimiles and solar power generators, it cannot be used in high-temperature environments of 120°C or higher, or in negative environments where conventional metal foil tapes with acrylic conductive pressure-sensitive adhesives cannot be used. It is possible to process the adhesive in a low-temperature environment of 30°C or less, and the adhesive can be used without any problems in its condition.

Patent applicant Shinto Paint Co., Ltd.

Claims (1)

[Claims] A conductive pressure-sensitive adhesive layer obtained by applying a conductive pressure-sensitive adhesive containing a methylphenyl copolymerized silicone resin and a conductive filler to a release liner coated with a methyl-based silicone resin is heated. A method for producing a heat-resistant conductive tape with a conductive pressure-sensitive adhesive, which comprises transferring the tape to a conductive support after crosslinking.