JP3221978B2 - Cushion material for hot press molding, method for producing the same, heat-resistant heat-sensitive adhesive sheet for cushion material for hot press molding, and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to electric, electronic, mechanical,
A heat-resistant heat-sensitive adhesive sheet that can be used as an adhesive or as a surface material for members requiring heat resistance in construction, automobiles, aircraft, and various other industries (hereinafter, the heat-resistant heat-sensitive adhesive sheet is simply called an “adhesive sheet” To be described) and a method for producing the same. In addition, the present invention
The present invention relates to a heat-resistant laminated material including a cushion material for hot press molding using such a heat-resistant adhesive sheet.

[0002]

2. Description of the Related Art For example, when a sheet-like material such as a decorative plywood or a printed board is formed by a hot press, a method of sandwiching a molding material between a hot platen and applying a constant pressure and heat is generally used. Have been. Such press molding is usually to place a metal mirror plate on the surface in direct contact with the molded object, while applying uniform pressure and heat to the entire surface of the molded object,
This is performed with a flat cushion material interposed between the hot platen and the mirror plate. Therefore, such a cushioning material is required to have excellent cushioning properties, heat resistance, durability and the like.

[0003] By the way, as such a cushioning material, a woven or nonwoven fabric layer made of organic or inorganic heat-resistant fiber such as aromatic polyamide fiber or glass fiber, a heat-resistant synthetic rubber layer, or the like is generally used. Various layers are appropriately selected in accordance with the type of the article to be molded, pressing conditions, and the like, and a laminated material obtained by combining and laminating them is used. Many types of materials having different materials and combinations are provided.

FIG. 7 shows an example of the structure of a general cushioning material for hot press molding. In the figure, (1) is a heat-resistant fiber layer, (2) is an adhesive layer, and (3) is a surface release layer. As the adhesive layer (2), a so-called glass epoxy-based heat-sensitive adhesive obtained by impregnating a glass cloth with an epoxy resin and forming a prepreg has conventionally been used.

[0005]

However, while the glass epoxy adhesive exhibits excellent properties in heat resistance and strength, it is a hard adhesive, so the shape of the adherend when subjected to compressive force. There was a problem that the glass cloth could not be followed, causing breakage of the glass cloth and peeling off early with the adherend.

On the other hand, the rubber-based adhesive is flexible and can follow the shape change, so that peeling, impact, vibration,
It is known that it has excellent durability against repeated compression and bending stress. However, those commonly used as rubber adhesives include natural rubber, SBR, NB
R, CR, IIR, reclaimed rubber, etc., all of which had the drawback of poor heat resistance.

An object of the present invention is to provide a heat-resistant heat-sensitive adhesive sheet having excellent heat resistance and having the advantages of a rubber-based adhesive, and a method for producing the same. Further, the object of the present invention is heat resistance, peeling, impact, vibration, repeated compression,
An object of the present invention is to provide a heat-resistant laminated material including a cushion material for hot press molding suitable for applications requiring durability against bending stress and the like.

[0008]

In order to achieve the above object, the present inventors have tried to use fluororubber as an adhesive, and have made repeated studies. Conventionally, fluororubber has excellent heat resistance, but it has been difficult to use it as an adhesive because of poor storage stability of a solution. That is, since it is necessary to sufficiently vulcanize in order to have an adhesive function, a vulcanizing agent and an accelerator having high activity must be blended.
Moreover, among the vulcanized rubbers, the vulcanization of a polyol vulcanization system or an amine vulcanization system, which is excellent in heat resistance, is promoted by an ionic reaction, so that methyl ethyl ketone (MEK), which is a common fluororubber solvent, is used. In such a case, vulcanization proceeds during storage or coating, and gelation occurs. As a result of repeated studies, the present inventor has found that there is a close relationship between the relative dielectric constant of the solvent and the storage stability of the fluororubber solution, and by improving the storage stability of the fluororubber solution, the present invention was improved. Was completed.

Hereinafter, means for solving the problems of the present invention will be described separately for a heat-resistant heat-sensitive adhesive sheet, a method for producing a heat-resistant heat-sensitive adhesive sheet, and a heat-resistant laminated material.

(Heat-resistant heat-sensitive adhesive sheet of cushioning material for hot press molding) The heat-resistant heat-sensitive adhesive sheet of cushioning material for hot press molding according to the present invention comprises a sheet-like base material made of a heat-resistant material and uncured on both surfaces. Fluoro rubber is applied, and a heat-resistant paint is applied on one side from above.

The substrate may be in any form as long as it is in the form of a sheet, such as a thin plate, a film, a woven fabric, a nonwoven fabric, and a paper, and the material is not particularly limited. However, in consideration of ease of operation, adhesion between the base material and the fluororubber, heat resistance, strength, shape stability, flexibility, and the like, it is most preferable to use a woven fabric of heat-resistant fibers as the base material. As such heat resistant fibers, polyamide fibers,
Aromatic polyamide fiber, polyimide fiber, polyamide imide fiber, polyester fiber, aromatic polyester fiber, polyarylate fiber, fluorine fiber, acrylic fiber,
Examples thereof include organic fibers such as polyvinyl alcohol fibers, and inorganic fibers such as glass fibers, carbon fibers, slag / rock fibers, ceramic fibers, and metal fibers.

In the heat-resistant and heat-sensitive adhesive sheet of the cushioning material for hot press molding according to the present invention, since the heat-resistant paint is applied, the heat resistance and the releasability of the surface can be improved.

Examples of the heat-resistant paint include fluorine resin, aromatic resin, phenol resin, melamine resin, epoxy resin, unsaturated polyester resin, silicone resin, polyimide resin, thermosetting acrylic resin, Organic heat-resistant paints such as hydrogenated NBR, fluoro rubber, EPM, EPDM, etc., alkali silicate, colloidal silica, acidic metal phosphate, dichromic phosphate,
Inorganic heat-resistant paints such as enamels, and alkyl silicate-based, alkyl titanate-based, organic and inorganic composite heat-resistant paints such as boron siloxane-based can be mentioned, each alone, or in a blend system, or as a copolymer Can be used.

[0014] Since fluoro rubber is expensive, it is not preferable to increase the coating amount more than necessary. However, if the coating amount is too small, sufficient adhesive strength cannot be obtained. The preferred amount of the applied fluororubber is such that the thickness when dried is 3 to 30 per side.
It is about 0 μm.

(Method for Producing Heat-Resistant Heat-Sensitive Adhesive Sheet for Cushion Material for Hot Press Molding) In the method for producing a heat-resistant heat-sensitive adhesive sheet for cushion material for hot press molding according to the present invention, the relative dielectric constant (ε) is 17
Compound 100 of unvulcanized fluoro rubber in the following solvent
After dissolving a weight part and an acid of 0.5 to 5 parts by weight, applying this solution to a sheet-like substrate made of a heat-resistant material, the fluororubber is dried without being vulcanized. More preferable solvent has a relative dielectric constant of 12 or less.

As the solvent, not only a solvent having a relative dielectric constant (ε) of 17 or less alone is used, but also a solvent having a relative dielectric constant (ε) of more than 17 alone is mixed with two or more solvents. However, it can be used if the relative dielectric constant (ε) is adjusted to 17 or less.

The relative dielectric constant (ε) of the solvent is determined by using a parallel disk type three-terminal electrode composed of a main electrode (L), a counter electrode (H), and a guard electrode (G) as shown in FIG. The electric capacity (C ′) when the space is filled with the solvent (X) is measured at 1 MHz, and can be obtained by substituting into the equation (1).

[0018]

(Equation 1)

Here, the vacuum capacity (C) of the three-terminal electrode is given by equation (2).

[0020]

(Equation 2)

The electric capacity (C ') of the three-terminal electrode
For details of the measurement, see pages 279 to 280 and 297 to 298 of "New Experimental Chemistry Course 5-Basic Technology 4 Electric" (edited by The Chemical Society of Japan, published in 1976 by Maruzen Co., Ltd.). There is an explanation.

If a solvent having a relative dielectric constant (ε) of 17 or less alone and its relative dielectric constant (ε) are exemplified, methyl n-propyl ketone (MPK; ε = 15.1), methyl n-butyl ketone ( MBK; ε = 12.2), methyl isobutyl ketone (MIBK; ε = 13.3), methyl n-amyl ketone (MAK; ε = 9.8), diethyl ketone (DE
K; ε = 17.0), methyl formate (ε = 8.5), ethyl formate (ε = 9.1), propyl formate (ε = 7.7),
Amyl formate (ε = 6.5), methyl acetate (ε = 7.
0), ethyl acetate (ε = 6.0), n-propyl acetate (ε = 5.7), n-butyl acetate (ε = 5.2), isobutyl acetate (ε = 5.2), n-acetic acid Amyl (ε = 4.
8), isoamyl acetate (ε = 4.6), tetrahydrofuran (THF; ε = 7.6) and the like.

If necessary, 0.5 to 5 parts by weight of an acid can be added to the solvent.
One that evaporates together with the solvent during drying is used. Such acids include formic acid, acetic acid, acetic anhydride, glacial acetic acid, butyric acid,
Butyric anhydride and the like.

The application of the unvulcanized fluoro rubber to the substrate can be performed by a knife coating method, a roll coating method, or dipping. When the viscosity of the fluororubber solution is low, the roll coating method or dipping is suitable.In this case, the fluororubber adheres to the surface of the base material, and the entire or partial base material is impregnated with the fluororubber. It will be. On the other hand, if it is desired to obtain a strong adhesive force between the adherend and the adhesive sheet, it is preferable to increase the solid content of the fluororubber to be adhered to the surface of the base material, so that the viscosity of the fluororubber solution is increased, It is preferable to apply by a knife coat method.

If the viscosity of the fluororubber solution is too high, it becomes difficult to apply the solution. Conversely, if it is too low, the solid content concentration is low, so the number of coatings must be increased, and the work is troublesome. Further, when a woven fabric is used as the base material, depending on the size of the weave, if the viscosity is too low, the solution passes through the weave and the coating cannot be performed well. For these reasons, the viscosity of the fluororubber solution is 300 to 4
It is preferable to keep the viscosity at 000 cp, and more preferable viscosity is 2,000 to 20,000 cp.

(Cushioning material for hot press molding) The cushioning material for hot press molding according to one aspect of the present invention comprises:
A non-vulcanized fluoroelastomer is applied to both sides of an adherend made of a heat-resistant material and having a nonwoven fabric layer on at least one surface, and a sheet-shaped substrate made of a heat-resistant material. A heat-resistant heat-sensitive adhesive sheet coated with a heat-resistant paint, the non-woven fabric layer of the adherend is brought into contact with the unvulcanized fluoro rubber of the adhesive sheet, and pressure and heat are applied to vulcanize the unvulcanized fluoro rubber. Then, the adherend and the adhesive sheet are bonded and integrated. The cushioning material for hot press molding according to another aspect of the present invention,
A first adherend made of a heat-resistant material and having a nonwoven fabric on upper and lower surfaces and a second adherend having a nonwoven fabric on the upper and lower surfaces are provided on both surfaces of a sheet-like base made of a heat-resistant material. Laminated via a first heat-resistant heat-sensitive adhesive sheet coated with unvulcanized fluoro rubber, and further, on the first adherend and the second adherend, the surface facing the adherend has an uncoated surface. Laminating the second and third heat-resistant heat-sensitive adhesive sheets coated with the vulcanized fluoro rubber,
An unvulcanized fluoro rubber is applied to the other surface of the second and third heat resistant heat-sensitive adhesive sheets, and a heat resistant paint is further applied thereon, and pressure and heat are applied to vulcanize the unvulcanized fluoro rubber. At the same time, the whole is bonded and integrated. The adherend may have a single-layer structure or a multilayer structure. (Manufacturing Method of Cushion Material for Hot Press Molding) According to the manufacturing method of the cushion material for hot press molding according to one aspect of the present invention, the unvulcanized fluoro rubber is dissolved in a solvent having a relative dielectric constant (ε) of 17 or less. After dissolving 100 parts by weight of the compound and 0.5 to 5 parts by weight of the acid and applying this solution to at least one surface of a sheet-like substrate made of a heat-resistant material, the fluororubber is dried without being vulcanized. A heat-resistant heat-sensitive adhesive sheet is prepared, and an adherend having a nonwoven fabric layer on at least one surface is brought into contact with the unvulcanized fluoro rubber of the adhesive sheet, and pressure and heat are applied to unvulcanized fluoro rubber. At the same time as vulcanization, the whole is bonded and integrated.

The adherend is made of heat-resistant fiber, heat-resistant synthetic resin,
A simple substance or a composite of various substances such as heat-resistant synthetic rubber, metal, and ceramics can be used in various forms such as a plate, a film, a woven fabric, a nonwoven fabric, and paper. At least one adherend has a nonwoven fabric layer on a surface facing the heat-resistant heat-sensitive adhesive sheet side.

The heat-resistant fibers include organic fibers such as polyamide fibers, aromatic polyamide fibers, polyimide fibers, polyamide imide fibers, polyester fibers, aromatic polyester fibers, polyarylate fibers, fluorine fibers, acrylic fibers, and polyvinyl alcohol fibers. And inorganic fibers such as glass fibers, carbon fibers, slag / rock fibers, ceramic fibers, and metal fibers.

Examples of the heat-resistant synthetic resin include a phenol resin, a melamine resin, a fluororesin, an epoxy resin, an unsaturated polyester resin, a silicone resin, a polyimide resin, a thermosetting acrylic resin, a furan resin, a urea resin,
A simple substance such as a diallyl phthalate resin and a polyurethane resin, or a blend or a copolymer may be used.

As the heat-resistant synthetic rubber, hydrogenated NB is used.
R, fluorine rubber, EPM, EPDM, and other simple or blended or copolymers.

[0031]

The fluororubber used in the present invention has a relative dielectric constant (ε) of 17 or less, preferably 12 or less.
The vulcanization reaction of the fluororubber solution can be delayed, and the storage stability of the solution is improved.

FIG. 9 shows the results of measurement on the relationship between the relative dielectric constant (ε) of the solvent and the number of days of gelation of the fluororubber solution. The composition of the fluororubber solution subjected to the measurement is as shown in Table 1.

[0033]

[Table 1]

In this measurement, a fluorine rubber compound of a polyol vulcanization type was used. Further, 1 part by weight of an acid (acetic acid) and 5 parts by weight of a vulcanization accelerator (calcium hydroxide) were added. With the above composition, various fluororubber solutions having different solvents were prepared, and a change in the viscosity of the solution was measured while keeping the temperature condition at 40 ° C. in a sealed state. The number of days until the viscosity of the solution reached 100,000 cp was defined as the number of gelation days.

From the measurement results, the relative dielectric constant (ε) of the solvent
And the number of days of gelation of the fluororubber are closely related to each other, and it is found that the storage stability of the fluororubber solution is improved by using a solvent having a relative dielectric constant (ε) of 17 or less. In particular, it is found that the storage stability is significantly improved when a solvent having a relative dielectric constant (ε) of 12 or less is used.

Next, the operation when an acid is added to the solvent will be described. By adding an acid to the solvent, the vulcanization reaction can be further delayed, and the storage stability of the fluororubber solution can be improved. Also, by adding an acid,
Experiments have shown that it also has the effect of increasing the viscosity of the solvent. When the acid is added, the amount is 0.5 to 5 parts by weight, preferably 1 to 3 parts by weight, per 100 parts by weight of the fluororubber compound. When the amount is less than 0.5 part by weight, the effect of adding the acid is not so much exhibited. If the amount is more than 5 parts, the solution viscosity becomes too high and coating becomes difficult,
Further, since the residual ratio of the acid after drying is increased, the vulcanization afterwards is adversely affected, which is not preferable.

FIG. 10 shows the measurement results of the relationship between the amount of acetic acid added and the number of gelation days and the solution viscosity of the fluororubber solution. The composition of the fluororubber solution subjected to the measurement is as shown in Table 2.

[0038]

[Table 2]

In this measurement, the solvent was methyl ethyl ketone (M
EK) was used. As the fluorine rubber compound, a polyol vulcanization type was used. Calcium hydroxide was added as a vulcanization accelerator. Then, a large number of fluororubber solutions having different amounts of acetic acid were prepared in this formulation, and the initial solution viscosity and the number of gelation days when the temperature was kept at 40 ° C. and sealed and stored were measured. The number of gelation days was the number of days until the viscosity of the solution reached 100,000 cp in the same manner as described above.

[0040]

Embodiments of the present invention will be described below.

1. (Preparation of Fluoro Rubber Compound) After kneading the fluoro rubber and each compounding agent shown in Table 3 with a kneader, an unvulcanized fluoro rubber ribbon was prepared by two rolls. Then, this was pulverized into a pellet with a pelletizer.

[0042]

[Table 3]

2. (Preparation of Fluorine Rubber Solution) An unvulcanized fluoro rubber solution was prepared using each material shown in Table 4. The solvent used here was n-butyl acetate (ε = 5.
2) and methyl isobutyl ketone (MIBK; ε = 13.
3) and three kinds of mixed solvents of methyl ethyl ketone (MEK; ε = 18.8), and the relative permittivity of the mixed solvent was ε = 11.1.

First, all of the above three types of mixed solvents were charged into a stirring tank, and then acetic acid was charged and stirred. Thereafter, the prepared fluororubber compound in the form of pellets was charged with stirring. The dissolution was carried out at a temperature of 50 ° C. or lower.

[0045]

[Table 4]

3. (Preparation of Heat-Resistant Heat-Sensitive Adhesive Sheet)
Was mixed according to the formula shown in Table 1. Then, this mixed solution was applied to a substrate by a knife coating method, the solvent was evaporated in a drying chamber, and the fluororubber was dried without being vulcanized.
Was prepared. During the coating, the viscosity of the fluororubber mixed solution was kept at 10,000 to 20,000 cp by adding toluene as needed.

[0047]

[Table 5]

Embodiment 1 FIG. 1 shows the structure of an adhesive sheet (4) according to Embodiment 1. In this embodiment, the thickness is about 1
The above mixed solution was applied three times on both surfaces of a substrate made of a 70 μm glass cloth (manufactured by Unitika Ltd .; UMG Glass H201SD) three times to obtain an adhesive sheet for double-sided bonding. The finished adhesive sheet has a configuration in which unvulcanized fluoro rubbers (6) and (6) are applied to both surfaces of a substrate (5) made of glass cloth. The adhesive sheet (4)
Had a total thickness of 210 μm.

Embodiment 2 FIG. 2 shows the structure of an adhesive sheet (7) according to Embodiment 2. In this embodiment, the first embodiment
The above mixed solution was applied three times on one side of the substrate made of the glass cloth used in the above. Then, the above mixed solution was applied only once on the other surface, and an aromatic acrylic resin liquid was further applied thereon as a heat-resistant paint once by knife coating. Thus, a surface layer adhesive sheet was obtained. The finished adhesive sheet is a substrate made of glass cloth (5)
Are coated with unvulcanized fluororubbers (6) and (6) on both sides, and an aromatic acrylic resin-based heat-resistant paint (8) is coated on one side from above. The overall thickness of the adhesive sheet (7) was 200 μm.

[Conventional Example] As a conventional example, the base material made of the glass cloth used in Example 1 was impregnated with an epoxy resin to prepare a prepreg, thereby obtaining a glass epoxy adhesive sheet for double-sided adhesion.

4. (Preparation of Heat Resistant Laminate) Example 3 FIG. 3 shows a laminated structure of a heat resistant laminate according to Example 3. In this example, the adherend A was formed in a multilayer structure and used as an inner layer. The adherend A was prepared by internally adding epoxy resin-based prepreg powder to paper made mainly of slag and rock fibers on both sides of a sheet (9) in which epoxy resin-based prepreg powder was internally added to paper made of aromatic polyamide fiber. The sheets (10) and (10) thus obtained are laminated, and the glass epoxy adhesive sheets (11) and (11) according to the above-mentioned conventional example are further laminated on both sides thereof, and aromatic polyamide fibers (Teijin Co., Ltd.) are further laminated on both sides thereof. Made by ^Conex®R )
(12), (1)
2) are laminated. Further, the adherend B is made of ethylene tetrafluoride-6-propylene copolymer resin (FE).
Fluorine resin film made of P) (manufactured by Daikin Industries, Ltd .; Neoflon ^{▲ R ▼ FEP) (13)} , (13)
Was used as a surface layer.

First, the double-sided adhesive sheets (4) and (4) of Example 1 are laminated on both surfaces of the multi-layer adherend A, and the adherends B (13) and (13) are further laminated on both surfaces. ) Were laminated and pressed at a temperature of 180 ° C. and a surface pressure of 20 kg / cm ² for 70 minutes to vulcanize the unvulcanized fluoro rubber and simultaneously bond and integrate the whole. The heat-resistant laminated material thus obtained is particularly suitable as a cushion material for hot press molding.

Fourth Embodiment FIG. 4 shows a laminated structure of a heat-resistant laminated material according to a fourth embodiment. In this embodiment, the adherend C
Aromatic polyamide fibers (manufactured by Teijin Ltd .; Conex ^{▲ R ▼)} as three of more becomes the base fabric reinforced needlepunched nonwoven (14) was used.

First, the adherends C (14), (14), (1)
4) is a double-sided adhesive sheet (4), (4) of Example 1.
, And the surface-side adhesive sheets (7) and (7) of Example 2 were further laminated on both surfaces thereof, and these were heated at a temperature of 18
The unvulcanized fluoro rubber was vulcanized by pressing at 0 ° C. and a surface pressure of 20 kg / cm ² for 70 minutes, and the whole was bonded and integrated. The heat-resistant laminated material thus obtained is particularly suitable as a cushion material for hot press molding.

Comparative Example 1 FIG. 5 shows a laminated structure of a heat-resistant laminated material according to Comparative Example 1. In Comparative Example 1, the conventional adhesive sheets (11) and (11) were used instead of the adhesive sheets (4) and (4) of Example 1 in Example 3. That is, the adhesive sheets (11) and (11) of the conventional example are laminated on both surfaces of the adherend A used in Example 3, and the adherends B (13) and ( 13) were laminated, and these were pressed at a temperature of 180 ° C. and a surface pressure of 20 kg / cm ² for 70 minutes to cure the glass epoxy prepreg and simultaneously bond and integrate.

Comparative Example 2 FIG. 6 shows a laminated structure of a heat-resistant laminated material according to Comparative Example 2. In Comparative Example 2, three adherends C (14), (14), and (14) used in Example 4 were laminated via the conventional adhesive sheets (11) and (11).
Further, the conventional adhesive sheets (11) and (11) are provided on both sides thereof.
Adherends B (13) and (13) used in Example 3 through
Are laminated at a temperature of 180 ° C. and a surface pressure of 20 kg / c.
pressed for 70 minutes at m ² was bonded and integrated at the same time curing the glass epoxy prepreg.

5. (Comparison of heat resistance) The thermal decomposition temperature of the vulcanized rubber of the fluoro rubber used for the adhesive sheets of Examples 1 and 2 and the cured product of the epoxy resin used for the conventional example were measured by a differential thermogravimetric simultaneous measuring device (Seiko Electronics Co., Ltd.). (Manufactured by Kogyo Co., Ltd .; SSC5200H). The result is shown in FIG. In FIG. 11, the horizontal axis represents temperature (° C.), and the vertical axis represents the degree of weight loss (%). From this figure, it can be seen that the fluororubbers of Examples 1 and 2 are more excellent in heat resistance of about 20 to 40 ° C. than the conventional epoxy resin.

6. (Comparison of durability) The laminated materials of Examples 3 and 4 and Comparative Examples 1 and ² were subjected to a heat press test at a heating temperature of 220 ° C and a pressure of 120 kg / cm ² for a heating time of 60 minutes and a cooling time of 15 minutes. The cycle was repeated in a press cycle, and the durability of the laminated materials was compared. Table 6 shows the results.

[0059]

[Table 6]

The laminates of Comparative Examples 1 and 2 did not show any abnormality in the inner layer, but peeled off on the surface layer after 50 times of pressing. In the laminate of Comparative Example 2, peeling occurred in the inner layer by pressing 100 times. In contrast, Examples 3 and 4
The laminated material of No. did not cause peeling of both the inner layer and the outer layer even after pressing 300 times.

[0061]

As described in detail above, the heat-resistant heat-sensitive adhesive sheet of the cushioning material for hot press molding according to the present invention uses a conventional glass-epoxy heat-resistant heat-sensitive adhesive because it uses fluorine rubber. It has excellent heat resistance even in comparison, and at the same time has excellent durability against peeling, vibration, repeated compression, bending stress and the like. In particular, since the heat-resistant paint is applied to the surface, the heat resistance and the releasability of the surface can be improved. In addition, in the production method, since the fluororubber having a relative dielectric constant (ε) of 17 or less is used, the storage stability of the fluororubber solution can be improved. In particular, in this fluoro rubber solution, the fluoro rubber compound 100
Since 0.5 to 5 parts by weight of the acid is added to the parts by weight, the storage stability of the fluororubber solution can be further improved. Since the fluororubber solution with improved storage stability can be easily applied to a base material, the fluororubber is applied to a sheet-like base material made of a heat-resistant material to produce the heat-resistant heat-sensitive adhesive sheet. It becomes easy to do. Further, in the cushioning material for hot press molding according to the present invention, the non-vulcanized fluoro rubber is brought into contact with the non-vulcanized fluoro rubber of the heat-resistant heat-sensitive adhesive sheet by bringing the non-vulcanized fluoro rubber into contact with the non-woven fabric layer on the surface of the adherend. And the adherend and the adhesive sheet are bonded and integrated. Adhesive sheets using fluoro rubber have excellent heat resistance and can follow the shape change of the non-woven fabric layer. However, good adhesion between the adherend and the adhesive sheet can be maintained for a long time, and no delamination occurs. In addition, since the adhesive sheet using fluororubber can follow the shape change of the nonwoven fabric layer, the cushioning properties of the nonwoven fabric layer can be fully utilized. Therefore, the cushioning material for hot press molding according to the present invention is excellent in cushioning property, heat resistance and durability. According to the method for producing a cushioning material for hot press molding according to the present invention, since the solvent for the fluororubber used for the adhesive sheet has a relative dielectric constant (ε) of 17 or less, the storage stability of the fluororubber solution is improved. Is improved, and it is easy to prepare a heat-resistant heat-sensitive adhesive sheet using fluororubber.Furthermore, since the nonwoven fabric layer of the adherend is bonded to the fluororubber layer of the heat-resistant heat-sensitive adhesive sheet, cushioning, heat resistance and A cushioning material for hot press molding having excellent durability can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a configuration of a heat-resistant heat-sensitive adhesive sheet according to Example 1.

FIG. 2 is a cross-sectional view illustrating a configuration of a heat-resistant heat-sensitive adhesive sheet according to Example 2.

FIG. 3 is a cross-sectional view illustrating a laminated structure of a heat-resistant laminated material according to a third embodiment.

FIG. 4 is a cross-sectional view illustrating a laminated structure of a heat-resistant laminated material according to a fourth embodiment.

FIG. 5 is a cross-sectional view illustrating a laminated structure of a heat-resistant laminated material according to Comparative Example 1.

FIG. 6 is a cross-sectional view showing a laminated structure of a heat-resistant laminated material according to Comparative Example 2.

FIG. 7 is a sectional view showing an example of the configuration of a general cushioning material for hot press molding.

FIG. 8 is a view showing a parallel disk type three-terminal electrode.

FIG. 9 is a graph showing measurement results of a relationship between the relative dielectric constant (ε) of a solvent and the number of gelling days of fluororubber.

FIG. 10 is a graph showing the results of measurement on the relationship between the amount of acetic acid added, the number of gelation days of the fluororubber solution, and the solution viscosity.

FIG. 11 is a view showing a thermal decomposition curve of a fluororubber and an epoxy resin.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Heat resistant fiber layer 2 Adhesive layer 3 Surface release layer 4 Heat resistant heat sensitive adhesive sheet (Example 1) 5 Base material: Glass cloth 6 Unvulcanized fluoro rubber 7 Heat resistant heat sensitive adhesive sheet (Example 2) 8 Heat resistance Paint 9 A sheet in which epoxy resin-based prepreg powder is internally added to paper made of aromatic polyamide fiber 10 A sheet in which epoxy resin-based prepreg powder is internally added to paper made mainly of slag / rock fiber 11 A glass epoxy adhesive sheet 12 Non-woven fabric of needle-punched reinforced needle punch 13 Fluorine resin film 14 Non-woven fabric of needle-punched non-woven fabric

Continuation of the front page (56) References JP-A-60-3131 (JP, A) JP-A-62-263272 (JP, A) JP-A-63-199785 (JP, A) JP-A-54-45386 (JP) JP-A-57-70174 (JP, A) JP-A-58-7646 (JP, U) JP-B-46-19800 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB Name) C09J 7/02 B29C 43/00 B30B 15/28 B32B 7/10 B32B 25/14

Claims (6)

(57) [Claims] An unvulcanized fluoro rubber is applied to both sides of a sheet-like substrate made of a heat-resistant material, and a heat-resistant paint is applied on one side from above. Thermal adhesive sheet. 2. The heat-resistant heat-sensitive adhesive sheet for a cushioning material for hot press molding according to claim 1, wherein the base material is a woven fabric of heat-resistant fibers. 3. A solution of 100 parts by weight of an unvulcanized fluoro rubber compound and 0.5 to 5 parts by weight of an acid in a solvent having a relative dielectric constant (ε) of 17 or less. A method for producing a heat-resistant heat-sensitive adhesive sheet for a cushioning material for hot press molding, wherein the fluororubber is dried in an unvulcanized state after being applied to the base material. 4. An unvulcanized fluoroelastomer is applied to both sides of an adherend made of a heat-resistant material and having a nonwoven fabric layer on at least one surface, and a sheet-like substrate made of a heat-resistant material. A heat-resistant heat-sensitive adhesive sheet coated with a heat-resistant paint on one side, and the non-woven fabric layer of the adherend is brought into contact with the unvulcanized fluororubber of the adhesive sheet, and pressure and heat are applied to the non-vulcanized rubber sheet. A cushioning material for hot press molding, in which an adherend and an adhesive sheet are bonded and integrated by vulcanizing fluorosulfur rubber. 5. A sheet-like sheet made of a heat-resistant material, comprising a first adherend made of a heat-resistant material and having a nonwoven fabric on upper and lower surfaces and a second adherend having a nonwoven fabric on the upper and lower surfaces. Laminated via a first heat-resistant heat-sensitive adhesive sheet formed by applying unvulcanized fluoro rubber to both surfaces of the base material, and further applied on the first adherend and the second adherend. Laminating second and third heat-resistant heat-sensitive adhesive sheets coated with unvulcanized fluoro rubber on the surface facing the body, and unvulcanized fluorine on the other surface of the second and third heat-resistant heat-sensitive adhesive sheets A rubber material for hot press molding, which is made by applying rubber, further applying a heat-resistant paint thereon, applying pressure and heat to vulcanize the unvulcanized fluoro rubber, and simultaneously bonding and integrating the whole. 6. A solvent having a relative dielectric constant (ε) of 17 or less is prepared by dissolving 100 parts by weight of an unvulcanized fluoro rubber compound and 0.5 to 5 parts by weight of an acid. After applying to at least one surface of the base material, the fluororubber is dried in an unvulcanized state to prepare a heat-resistant heat-sensitive adhesive sheet, an adherend having a nonwoven fabric layer on at least one surface, and the adhesive sheet A method for producing a cushioning material for hot press molding, in which the unvulcanized fluororubber is brought into contact with the rubber material, and pressure and heat are applied to vulcanize the unvulcanized fluororubber and simultaneously bond and integrate the whole.