Method for adhesion treatment of heat-resistant sheet and pressure-sensitive adhesive sheet

【0001】

[Technical field to which the invention belongs]

The present invention relates to an adhesive tape, and more particularly to an adhesive treatment method for a heat-resistant sheet relating to an adhesive treatment agent applied between the pressure-sensitive adhesive and a base material, and an adhesive tape using the base material produced by the method.

【0002】

[Conventional technology]

Due to its simplicity, adhesive tapes have come to be used in many fields in recent years, and various products have been developed and used for many purposes. Among them, depending on the application, there are many cases where the tape once attached is peeled off and a new tape is attached to the peeled surface. In such a case, the adhesive tape is required to have not only the function of simply "sticking" but also the function of not leaving the adhesive (glue) on the adherend surface when the tape is peeled off. As for the adhesive tape having such a function, some proposals have been made so far, and some have been put into practical use. For example, by forming an adhesive after applying an undercoat layer to a base material, the adhesion between the tape base material and the pressure-sensitive adhesive layer, that is, the anchoring property between the base material and the pressure-sensitive adhesive layer is improved, and glue to the adherend is improved. Adhesive tapes with little remaining have been proposed (for example, Patent Document 1 etc.). Further, another resin layer is provided as the support (base material), the pressure-sensitive adhesive layer and the intermediate layer thereof, and the anchoring force between the support, the intermediate layer and the pressure-sensitive adhesive layer is excellent, and therefore the adhesive residue after peeling is left. Adhesive tapes that do not exist have been proposed (for example, Patent Document 2 etc.).

[Patent Document 1]

Japanese Unexamined Patent Publication No. 2000-191989 [Patent Document 2]

Japanese Unexamined Patent Publication No. 2000-63774 [0003]

[Problems to be Solved by the Invention]

However, such a conventional technique is an adhesive tape that can be realized by a combination of a specific base material, an adhesive, and an intermediate layer, and exhibits extremely excellent functions in some applications, and sufficiently satisfies the above requirements. On the other hand, as a multipurpose adhesive tape, its function may not always be utilized. Further, in the case of producing an adhesive tape composed of an adhesive, a base material, and an adhesive to be applied between them, various studies have been conducted on the adhesive, but a method for completely eliminating adhesive residue has still been found. The reality is that it has not. In particular, in applications where the operating temperature exceeds 200 ° C, there is a large amount of adhesive residue, and improvement is required.

【0004】

Therefore, an object of the present invention is to provide an adhesive treatment method for improving the anchoring force in order to solve the above-mentioned problems, and to provide an adhesive having an enhanced cohesive force on the adhesive treatment surface produced by such a method. After coating, and in some cases, an undercoating agent is applied, an adhesive is applied to supply an adhesive tape that does not leave adhesive residue.

【0005】

[Means for solving problems]

As a result of diligent research on a method for satisfying this requirement, the present inventors have found that an excellent anchoring force can be obtained by applying a predetermined adhesive treatment method to a heat-resistant sheet, and have completed the present invention. ..

【0006】

That is, it is a method of adhering a heat-resistant sheet, in which an adhesive treatment solution composed of an adhesive treatment agent and a solvent is applied to at least one surface of the heat-resistant sheet, and then the solvent in the heat-resistant sheet is rapidly evaporated to solidify. It is characterized in that pores and / or cracks in a continuous foam state are generated in the component, and the adhesive is heated to a temperature at which it is molded. By further making the surface of the adhesive layer having an adhesive effect uneven by means such as foaming and cracking, the aim is to improve the anchoring effect by entwining the adhesive with the uneven surface.

【0007】

Further, it is an adhesive tape obtained by applying an adhesive to a base material (hereinafter referred to as "intermediate") produced by such a method, and the adhesive treatment agent is empty in a continuous foam state in the solid component thereof. It is characterized in that it is molded with holes or / and cracks. By applying an adhesive with enhanced cohesive force to the intermediate having the anchoring effect as described above, and in some cases, applying an undercoating agent and then applying the adhesive, it is possible to make an adhesive tape without adhesive residue after peeling. Become.

【0008】

Further, it is preferable that the adhesive treatment solution is composed of silica particles, a fluororesin, a surfactant and water, and the solid component thereof is 5 to 80%. Under the condition of such a combination and composition of materials, a stable adhesive treatment can be performed, and an adhesive tape having uniform quality can be provided.

【0009】

As the base material of the adhesive tape, it is preferable to use a polyimide film, a polyamide sheet, a fluorine film, or an impregnated cloth in which a glass cloth is impregnated with a fluororesin. Such a base material can be applied to a wide variety of applications with adaptability to an adhesive treatment agent and an adhesive while ensuring certain characteristics of the adhesive tape such as heat resistance and strength.

【0010】

Further, when the pressure-sensitive adhesive is applied to the adhesive-treated surface, the gel content of the pressure-sensitive adhesive is preferably 20 to 60%. It was found that if the gel fraction is within the range, the cohesive force of the adhesive can be increased, and even if the tape is peeled off after use at a high temperature, an adhesive tape without adhesive residue can be obtained.

【0011】

Further, the pressure-sensitive adhesive is preferably a silicone-based pressure-sensitive adhesive. As a result, it is possible to apply it to a wide variety of applications with compatibility with an adhesive treatment agent while ensuring the characteristics of the adhesive tape such as resistance to high temperature, strength, and flexibility.

【0012】

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described.

【0013】

In the method for adhering a heat-resistant sheet of the present invention, an adhesive-treating solution consisting of an adhesive-treating agent and a solvent is applied to at least one surface of the heat-resistant sheet, and then the solvent in the adhesive-treating solution is rapidly evaporated to form a solid component. It is characterized in that pores and / or cracks in a continuous foam state are generated therein, and the adhesive treatment agent is heated to a molding temperature. The purpose is to improve the anchoring effect by entwining the adhesive with the uneven surface by further making the surface of the undercoating agent layer having an adhesive effect uneven by means such as foaming and cracking.

【0014】

Further, the intermediate produced by such a method is applied with an adhesive and used as an adhesive tape. That is, it is possible to produce an adhesive tape characterized by being molded in a state of having pores and / or cracks in a continuous foam state in the solid component in the adhesive treatment agent, and it becomes an intermediate having an excellent anchoring effect. By applying an adhesive having an enhanced cohesive force, or in some cases, applying an undercoating agent and then applying the adhesive, an adhesive tape having no adhesive residue after peeling can be obtained.

【0015】

The adhesive treatment solution used in the present invention is composed of an adhesive treatment agent and a solvent, and a cross-linking agent, a curing agent, an organic or inorganic filler can be added as needed.

【0016】

As the adhesive treatment agent, polyester resin, melamine resin, acrylic resin, silicone resin, fluororesin such as PFA, FEP, and PTFE are selected according to the composition of the tape. The amount of application in the dry state is 0.5 to 20 g / m.² , Preferably 1 ~ 10g / m² When curing is required, a curing agent such as an isocyanate-based or amine-based curing agent or a peroxide such as pennzoil peroxide is used. The coating amount is 0.5g / m² If it is less than, no pores or / or cracks in a continuous foam state will occur in the adhesive treatment agent even if it is heated, and 20 g / m.² Even if it is applied in excess of, the effect commensurate with the amount of application cannot be obtained.

【0017】

As the solvent, toluene, xylene, methyl ethyl ketone, ethyl acetate, butyl alcohol, water and the like, and mixtures thereof are used.

【0018】

As the filler, an organic resin powder such as melamine resin, evoxy resin, acrylic resin or the like or an inorganic powder such as magnesium oxide, aluminum oxide or silica is used. The amount to be added is in the range of 5 to 80%, preferably 10 to 60% of the total weight of the adhesive treatment agent.

【0019】

It is better to heat the material at a temperature (° C) or higher, which is obtained by adding 20 to the boiling point of the solvent used, and at a high temperature unless the adhesive treatment agent is molded and the material is substantially deteriorated. In the case of a mixed solvent, the heating temperature is determined based on the boiling point of the highest solvent as described above.

【0020】

Further, the adhesive treatment solution is composed of silica particles, a fluororesin, a surfactant and water, and the solid component thereof is preferably 5 to 80%, more preferably 10 to 50%. If it is less than 5%, the adhesive will not have pores or / or cracks in a continuous foam state even if it is heated, and if it exceeds 80%, the viscosity of the adhesive solution will increase and the coated surface will become rough. And the quality is not stable. Stable adhesion processing is possible under the condition of such a combination and composition of materials.

【0021】

As the base material of the adhesive tape, it is preferable to use a polyimide film, a polyamide sheet, a fluorine film, or an impregnated cloth in which a glass cloth is impregnated with a fluororesin. Such a base material is a material having excellent heat resistance, ensuring the characteristics of the adhesive tape such as strength and processability, and also having excellent adaptability to the adhesive through the adhesive treatment. In addition to the above, examples of the base material used in the present invention include papers, polyester films, metal foils, and the like.

【0022】

Further, when the pressure-sensitive adhesive is applied to the adhesive-treated surface, the gel content of the pressure-sensitive adhesive is preferably 20 to 60%. When the gel fraction of the pressure-sensitive adhesive is less than 20% as the amount of the cross-linking agent, if the pressure-sensitive adhesive tape is peeled off after use, the pressure-sensitive adhesive is coagulated and broken, causing a problem that the pressure-sensitive adhesive remains on the adherend. If the gel fraction exceeds 60%, the adhesive becomes hard and the adhesive strength decreases, which may cause a problem that the adhesive tape can be shaved during use. It was found that if the gel fraction is within the range, the cohesive force of the adhesive can be increased, and even if the tape is peeled off after use at a high temperature, an adhesive tape without adhesive residue can be obtained.

【0023】

Further, the pressure-sensitive adhesive is preferably a silicone-based pressure-sensitive adhesive. It has the properties required for adhesive tapes such as resistance to high temperature, strength, and flexibility, and is compatible with adhesive treatment agents. In addition to silicone-based adhesives, rubber-based adhesives, acrylic-based adhesives, etc. can also be used and are selected according to the application, and sulfur, melamine-based resin, isocyanate-based resin, peroxide, etc. are used as the cross-linking agent. Ru.

【0024】

The thickness of the adhesive is generally 4 to 70 μm. If it is less than 4 μm, the adhesive strength is low and it may come off during use. No particular effect is observed even if it exceeds 70 μm, and in the following heat-sealing applications, the thermal conductivity in the thickness direction of the adhesive tape decreases, which causes inconvenience.

【0025】

In the present invention, by adopting the sheet bonding treatment method as described above, it is possible to improve the anchoring force, and apply an adhesive having an enhanced cohesive force, and in some cases, apply an undercoating agent and then adhere. By applying the agent, it is possible to supply an adhesive tape that does not leave adhesive residue after peeling. When such an adhesive tape is used for masking tape, heat-sealing tape, etc., the present invention does not leave adhesive residue on the tape even when the tape is repeatedly attached and detached. It is useful as an adhesive tape that can make the best use of its excellent anchoring power and cohesive power, and satisfies the functions required for each application to the maximum extent.

【0026】

[Example]

Hereinafter, examples showing the configuration and effects of the present invention will be described. The evaluation items in each example are as follows. It should be noted that each of these examples does not limit the present invention.

【0027】

<Evaluation method> (1) Measurement was performed based on JIS C 2107 using a sample having an adhesive strength of 19 mm × 200 mm. (2) Adhere the adhesive residue sample (19 mm x 200 mm) to a stainless steel plate (SUS304BA plate) with one reciprocating 2 kg roller, leave it at room temperature for 30 minutes, leave it at a predetermined temperature for 240 hours, and then leave it at room temperature for 30 minutes. did. Next, using a Tencilon type universal tensile tester, the adhesive was peeled off at a speed of 30 mm / min and 300 mm / min in the 180 ° direction at room temperature, and the residual state of the adhesive on the SUS surface was examined. Here, the predetermined temperature means 80 ° C in the case of an acrylic adhesive and 200 ° C in the case of a silicone adhesive. (3) Gel fraction Obtained by the method described below 1) Prepare a sample of 19 mm x about 250 mm. 2) Weigh this sample. (Ag) 3) Immerse this sample in about 300 ml of toluene for 48 hours. 4) After air-drying for 30 minutes, remove toluene at 120 ° C for 2 hours. 5) Take out to room temperature and leave for 30 minutes. 6) Weigh this sample. (Bg) 7) Remove the adhesive from the sample and use only the base material. 8) Weigh the base material. (Cg) 9) Calculate the gel fraction (%) using Equation 1 below. Gel fraction (%) = (BC) / (AC) x 100 Formula 1 (4) Anchoring force On the glue surface of the sample (19 mm x 200 mm), Kapton adhesive tape (Nitto Denko: No.360, 1 mil product) Stick the glued surfaces together with a hand roll. After leaving it at room temperature for 24 hours, a test sample was prepared so that it could be peeled off between the base material of the sample and the adhesive, and this was peeled off at a speed of 300 mm / min in the 180 ° direction with a Tencilon type tensile tester. , Asked for anchoring power.

【0028】

<Example 1> Amount of a 10% toluene solution of acrylic resin (Mitsubishi Rayon: product name Acrypet VH) applied to one side of a Boliimide film (Toray DuPont: product name Kapton Film 100H) in a dry state. Is 4g / m² Apply to the above and immediately heat at 170 ° C for 5 minutes. Next, a 30% toluene solution in which 5 parts by weight of an isocyanate-based curing agent is added to 100 parts by weight of an acrylic pressure-sensitive adhesive (2 ethylhexyl acrylate / acrylic acid = 100/1: molecular weight 700,000) is added to this adhesive-treated surface in a dry state. Was applied so that the coating thickness of was 35 μm. This was allowed to stand at room temperature for 10 minutes and then heated at 130 ° C. for 5 minutes to cure to obtain an adhesive tape.

【0029】

<Example 2> 90 g / m of PTFE resin on both sides of a glass cloth (manufactured by Kanebo Co., Ltd .: trade name KS 1090)² On one side of the applied impregnated cloth, 100 parts by weight of PFA resin (manufactured by Daikin Industries, Ltd .: trade name Neoflon PFA AD-2CR), 60 parts by weight of silica (manufactured by Nissan Chemical Industries, Ltd .: trade name Snowtex N), surfactant ( Daikin Industries, Ltd .: Product name Neugen EA-137) Applying 2 parts by weight and 300 parts by weight of water of the adhesive treatment solution in a dry state is 1.5 g / m.² It was applied so that it was immediately heated at 200 ° C for 1 minute, and then at 370 ° C for 30 seconds. A 35% xylene solution of 2.5 parts by weight of benzoyl peroxide is applied to 100 parts by weight of the silicone adhesive on the surface to which the adhesive is applied so that the coating thickness in the dry state is 45 μm, and then the temperature is 80 ° C. for 3 minutes. Subsequently, it was heated at 200 ° C. for 5 minutes to obtain an adhesive tape.

【0030】

<Comparative Example 1> An adhesive tape was obtained in the same manner except that the heating temperature after coating the acrylic resin in Example 1 was changed at 80 ° C. for 10 minutes.

【0031】

<Comparative Example 2> The amount of acrylic resin applied in Example 1 was 0.2 g / m.² Adhesive tape was obtained in the same manner except that it was changed to.

【0032】

<Comparative Example 3> An adhesive tape was obtained in the same manner except that the isocyanate-based curing agent of Example 1 was changed to 1 part by weight.

【0033】

<Comparative Example 4> An adhesive tape was obtained in the same manner except that the heating temperature after applying the adhesive solution of Example 2 was changed at 100 ° C for 10 minutes.

【0034】

<Comparative Example 5> The amount of the adhesive treatment solution of Example 2 applied in a dry state is 0.1 g / m.² Adhesive tape was obtained in the same manner except that it was changed to.

【0035】

<Comparative Example 6> An adhesive tape was obtained in the same manner except that the adhesive solution of Example 2 was changed to 0.5 parts by weight of benzoyl peroxide.

【0036】

<Test results> Table 1 shows the test results of each example for the above four evaluation items.

[table 1]<img file="JP2004123769A_D0001.tif" /> 【0037】

As the results in Table 1 show, in Examples 1 and 2, there was no adhesive residue, the anchoring power was high, and appropriate results were obtained for each evaluation item. On the other hand, in all of Comparative Examples 1 to 6, adhesive residue was generated, which was an inappropriate result. In particular, in Comparative Examples 1, 2, 4 and 5, the anchoring force was very low and so-called anchoring fracture occurred, and in Comparative Examples 3 and 6, the anchoring force was high but the gel fraction was very low. So-called cohesive fracture occurred due to a decrease in cohesive force.

【0038】

[Effect of the invention]

As described above, in the method for adhering a heat-resistant sheet of the present invention, the adhesive or primer can be obtained by further making the surface of the adhesive layer having an adhesive effect uneven by means such as foaming and cracking. Entangled on uneven surfaces, the anchoring effect has been greatly improved.

【0039】

Therefore, in the case of an adhesive tape prepared by applying an adhesive having an enhanced cohesive force to an intermediate produced by such a method, and in some cases, applying an undercoating agent and then applying the adhesive, the anchoring force and the cohesive force are high. It is very excellent, and when it is peeled off, there is no adhesive residue. This eliminates the need to clean the adherend even when reattaching, and eliminates the inconvenience of having to wait for cleaning to cool to room temperature, especially when used at high temperatures. In addition, the effect of eliminating the need for an organic solvent that must be used for cleaning can be obtained. In other words, for the former, shortening the time leads to improvement in productivity, and for the latter, further improvement in hygiene and safety can be obtained, which is a more advanced technical effect.

【0040】

Further, by limiting the adhesive treatment solution to a specific material and setting the solid components thereof in a certain range, more stable adhesive treatment becomes possible, and an adhesive tape having high anchoring power and uniform quality can be provided. It will be possible.

【0041】

Similarly, when a polyimide film or the like is selected as the base material of the adhesive tape, it has compatibility with the adhesive treatment agent and the adhesive while ensuring the characteristics of the adhesive tape such as more excellent heat resistance and strength. It can be applied to a wide variety of applications.

【0042】

Further, when applying the adhesive to the adhesive-treated surface, if the gel content of the adhesive is set within a predetermined range, the cohesive force of the adhesive can be increased, and even if the tape is peeled off after use at a high temperature, the adhesive residue remains. You can get a non-adhesive tape.

【0043】

Further, when the above-mentioned pressure-sensitive adhesive is a silicone-based pressure-sensitive adhesive, it has a wide variety of adaptability to an adhesive treatment agent while ensuring the characteristics of the pressure-sensitive adhesive tape such as resistance to high temperature, strength, and flexibility. It can be applied to applications.