JPH0474645A - Composite sheet for resin molding - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention "Industrial Application Field" The present invention is applied to the outside of the molding resin in order to maintain the vacuum between the mold or base material and the resin sheet during vacuum forming or pressure forming of the resin. Regarding the sheet material used.

[Conventional technology] Vacuum forming of resin involves forming a resin film, resin sheet, fiber-reinforced resin sheet, prepreg (e.g. glass fiber, synthetic fiber, carbon fiber, or other fiber material) with resin on the surface of a mold or base material. The resin sheet or prepreg is placed in a predetermined shape while heating, by covering the surface with a gas barrier sheet with low gas permeability and keeping the mold or base material side in a vacuum or reduced pressure state. It is something to be molded.

In addition, pressure molding employs a method of reducing the pressure from the mold or base material side and simultaneously blowing compressed air from the gas barrier sheet side.

Conventionally, polyester or nylon films or sheets have often been used as vacuum forming sheets, and some sheets have also been used consisting of silicone rubber alone.

[Problems to be Solved by the Invention] However, conventional polyester and nylon films or sheets lack heat resistance and are unsuitable for high-temperature vacuum forming or pressure forming. Furthermore, although sheets made of silicone rubber alone have heat resistance, they have poor gas permeability and cannot maintain a vacuum state for long periods of time.

SUMMARY OF THE INVENTION In order to solve the problems of the prior art, an object of the present invention is to provide a composite sheet that has high heat resistance, low gas permeability, and is excellent in vacuum forming and/or pressure forming.

[Means for Solving the Problems] In order to achieve the above object, the composite sheet for resin molding of the present invention maintains a vacuum between the mold or the base material and the resin during vacuum forming and/or pressure forming of the resin. A gas barrier sheet is used on the outside of a molding resin for the purpose of the present invention, and the surface of the sheet in contact with the molding resin is made of a silicone rubber layer, and the outside of the silicone rubber layer is provided with a fluorine rubber layer. Features.

In the configuration of the present invention, the silicone rubber layer preferably has a thickness of 0.3 to 5.0 mm, and the fluororubber layer preferably has a thickness of 0.1 to 2.0 mm.

Further, in the configuration of the present invention, it is preferable that at least one of the silicone rubber layer and the fluorine rubber layer is colored black.

Furthermore, in the configuration of the present invention, the fluororubber layer is
The elastomer is preferably an elastomer made of a polyolefin (co)polymer containing at least one component of a fluorine-containing ethylene unit or a fluorine-containing propylene unit.

Further, in the configuration of the present invention, the composite sheet is preferably one used for vacuum and/or pressure air heating molding of a fiber reinforced resin sheet or prepreg sheet.

[Function] According to the configuration of the present invention, the surface of the composite sheet that comes into contact with the molding resin is made of a silicone rubber layer, and the outside of the silicone rubber layer is provided with a fluorine rubber layer.
A composite sheet that has high heat resistance and low gas permeability and is excellent in vacuum forming or pressure forming can be obtained.

In other words, both silicone rubber and fluorine rubber have a heat resistance temperature (continuous use temperature in air) of approximately 200°C.
℃, up to about 230℃ in some cases, and has excellent heat resistance.

The gas permeability is 1 c of area per second at a pressure difference of 1 atm.
nf is the amount of gas that permeates through a 1 cm thick film (volume CC under standard conditions), and silicone rubber has an example of nitrogen 2000. Oxygen 4000. While carbon dioxide gas is 16,000, for example, fluorine rubber has 4 to 7 nitrogen and 1 oxygen.
5 to 23, carbon dioxide gas 29 to 78 [However, all units are CC'mm/d-5ec-cmHg) x 10-1
0 pieces. However, by laminating a fluorine-based rubber on a silicone rubber, a composite sheet with low gas permeability can be obtained.

Moreover, since the silicone rubber layer is disposed on the surface that comes into contact with the molding resin, good mold releasability from the resin can be maintained.

In addition, since silicone rubber and fluorine rubber are laminated, good elasticity can be maintained, and fine molding and deep drawing are possible during vacuum or pressure molding.

Next, the operation of a preferred configuration of the present invention will be explained.

First, the thickness of the silicone rubber layer is set to 0.3~5゜Qmm.
In particular, the thickness of the fluorine rubber layer is 0.5 to 1.5 mm. 1-2. The reason why it is preferable to set Qmm, particularly in the range of O03 to 1.0 mm, is to maintain better elasticity. A preferable elongation rate is 300% or more.

On the other hand, since fluororubber has little elongation, if the fluororubber layer is thick, the sheet tends to not follow a predetermined shape during vacuum forming.

Next, it is preferable that at least one of the silicone rubber layer and the fluorine rubber layer be colored black to promote heat absorption when far infrared rays or infrared rays are used as a heat source during vacuum or pressure molding. This is because heating efficiency can be improved. As the black coloring material, carbon black, other pigments, dyes, etc. can be used as appropriate.

Next, the fluorine rubber layer is preferably an elastomer made of a polyolefin (co)polymer containing at least one component of a fluorine-containing ethylene unit or a fluorine-containing propylene unit because it has particularly excellent gas permeability. . Note that as long as the elastomer is made of the polyolefin (co)polymer, it may be a homopolymer or a copolymer.

Next, it is preferable that the composite sheet of the present invention is used for vacuum and/or air pressure thermoforming of a fiber-reinforced resin sheet or prepreg sheet. This is because epoxy resins, polyester resins, nylon resins, etc. must be heat-molded at high temperatures and are suitable for such uses.

[Example] The present invention will be explained in more detail with reference to Examples below.

FIG. 1 shows a cross section of a composite sheet according to an embodiment of the present invention, and FIG. 2 shows a cross section of the same composite sheet when vacuum forming is performed.

In Fig. 1, 1 is a composite sheet, 2 is a silicone-t
For example, conventional silicone rubbers such as methyl silicone rubber, phenyl silicone rubber, vinyl silicone rubber can be used in the layer. Preferably JIS-A hardness is 20
~50° silicone rubber. 3 is a fluorine-based rubber layer, and for example, a tetrafluoroethylene-propylene copolymer elastomer (the following formula [A]), a vinylidene fluoride-hexafluoropropylene copolymer elastomer (the following formula [B]), etc. can be used.

(However, n and m indicate the number of repeating units, and may be the same number or different numbers.) The rubber of the formula [A] is manufactured by the trade name "Afros" (manufactured by Asahi Glass-Japan Synthetic Rubber Co., Ltd.). ), etc., and the rubbers of the above [B] type have the product names "Paiton" (manufactured by DuPont), "Daiel" (manufactured by Daikin),
Examples include "Florel" (3M).

Any method can be adopted as the lamination method, such as extrusion integral molding, integration using a calendar molding machine, heat vulcanization of a single sheet, or bonding with an adhesive.

FIG. 2 shows an example of vacuum forming using the composite sheet of the present invention. That is, the prepreg sheet material 4 is placed on a mold, its surface is covered with the composite sheet of the present invention, the inner surface is kept under reduced pressure by a vacuum pump (not shown), and heated to shape the prepreg into a predetermined shape. Shape. When a base material is used instead of the mold 5, the prepreg sheet material 4 is integrated with the base material.

Note that 6 is a pressure reducing cock (or valve) and 7 is a vacuum line.

This will be explained in more detail below using experimental examples.

Example 1 Methyl vinyl polysiloxane rubber (silicone rubber)
The components and the etrafluoroethylene-propylene copolymer elastomer (fluorine rubber) of the formula [A] were pulled out in sheet form from each Kander molding machine, and after bonding them together, they were heated and vulcanized to form the sheet shown in Figure 1. A composite sheet as shown was manufactured.

The silicone rubber layer had a thickness of 1.1 mm, the fluorine rubber layer had a thickness of 0.5 mm, and the total thickness was 1.6 mm.

Using the obtained composite sheet, vacuum forming was performed as shown in FIG. The temperature of vacuum forming is 180℃ in the autoclave, and the initial degree of vacuum (degree of reduced pressure) is 20mmHg (
However, the normal pressure was 760 mmHg) and the heating time was 60 minutes. Fiber reinforced resin sheet used for vacuum forming (F
RP) was a glass fiber reinforced polyester sheet. The degree of decrease in the degree of vacuum at this time was measured.

As a comparative example, a sheet (thickness: 1.6 mm) made of only a single layer of silicone rubber was used to measure the degree of decrease in the degree of vacuum.

The results are shown in Table 1.

From the results shown in Table 1, it was confirmed that the product of this example had excellent heat resistance and gas barrier properties, and good vacuum forming was possible. Moreover, the peelability from the resin was also excellent.

On the other hand, the comparative example had high gas permeability, and some corners of the molded product were raised, making it difficult to accurately mold the molded product into a predetermined shape.

Example 2 In Example 1, far infrared rays were used as the heat source for vacuum forming, and carbon black was added to both the silicone rubber component and the fluorine-based rubber to give them a black color.

As a result, heat absorption efficiency was high and heating vacuum forming could be performed in a short time.

Example 3 In Example 1, at the same time as vacuum forming from the mold side,
Compressed air at 3 atmospheres was blown from the outside of the gas barrier film.

As a result, as in Example 1, good molding was achieved.

Example 4 Vacuum forming was carried out in the same manner as in Example 1 except that the vinylidene fluoride-hexafluoropropylene copolymer elastomer of the formula [81] was used as the fluorine rubber.

As a result, as in Example 1, good molding was achieved.

Example 5 An experiment was carried out in the same manner as in Example 1, except that a prepreg sheet in which an epoxy resin was present in a carbon fiber fabric was used instead of the glass fiber reinforced polyester sheet.

As a result, as in Example 1, good molding was achieved.

Example 6 In Example 1, a base material made of a triaxial carbon fiber fabric was used instead of the mold 5, and a prepreg made of a carbon fiber fabric with a heat-resistant polyamide resin was used as the prepreg plate 4. Vacuum forming of the main body was performed.

The plane size was 2 m x 4 m, and the height of the unevenness on the surface of the base material was 4 to 5 cm. Then, when vacuum forming was performed in the same manner as in Example 1, there was no lifting of a part of the corner, and it was successfully formed into a predetermined shape.

As explained above, the composite sheet of the example of the present invention has excellent heat resistance and gas barrier properties, and also has a high elongation rate, so it can be made into a composite sheet useful for vacuum forming and pressure forming. It is particularly suitable for forming structural materials such as aircraft bodies and wings, and non-structural materials such as doors and flooring using prepreg sheets such as carbon fiber.

[Effects of the Invention] As explained above, according to the present invention, the surface of the composite sheet that comes into contact with the molding resin is made of a silicone rubber layer, and the outside of the silicone rubber layer is provided with a fluorine rubber layer. A composite sheet that has high heat resistance and low gas permeability and is excellent in vacuum forming or pressure forming can be obtained. Moreover, since the silicone rubber layer is disposed on the surface that comes into contact with the molding resin, good patternability with the resin can be maintained.

In addition, since silicone rubber and fluorine rubber are laminated, good elasticity can be maintained, and fine molding and deep drawing are possible during vacuum or pressure molding.

Next, according to a preferred configuration of the present invention, the thickness of the silicone rubber layer is 0.3 to 5.0 mm, particularly 0.5 to 1.5 mm.
mm, and the thickness of the fluorine rubber layer is 0.1 to 2.0 mm, particularly 0.3 to 1.0 mm. Since the range is Qmm, stretchability can be maintained better. The preferred elongation rate is 300
% or more.

Next, since at least one of the silicone rubber layer and the fluorine rubber layer is colored black, when far infrared rays or infrared rays are used as a heating source during vacuum or pressure molding, heat absorption is promoted and heating efficiency is increased. can be improved.

Next, since the fluorine rubber layer is an elastomer made of a polyolefin (co)polymer containing at least one component of a fluorine-containing ethylene unit or a fluorine-containing propylene unit, it has particularly excellent scum permeability.

Next, the composite sheet of the present invention is used for thermoforming a fiber-reinforced resin sheet or prepreg sheet in vacuum and/or air pressure, and is therefore useful for applications in which thermoforming is performed at high temperatures.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a composite sheet according to an embodiment of the present invention, and FIG.
The figure shows a cross-sectional view when vacuum forming the same composite sheet. 1... Composite sheet, 2... Silicone rubber layer, 3...
...Fluororubber layer, 4...Prepreg sheet material,
5...Mold, 6...Reduction cock (or valve), 7.
...Vacuum line.

Claims (5)

[Claims] (1) A gas barrier sheet used on the outside of the molding resin to maintain a vacuum between the mold or base material and the resin during vacuum molding and/or pressure molding of the resin, the sheet being 1. A composite sheet for resin molding, characterized in that a contacting surface is made of a silicone rubber layer, and a fluorine rubber layer is provided on the outside of the silicone rubber layer. (2) The composite sheet for resin molding according to claim 1, wherein the silicone rubber layer has a thickness of 0.3 to 5.0 mm, and the fluororubber layer has a thickness of 0.1 to 2.0 mm. (3) The composite sheet for resin molding according to claim 1, wherein at least one of the silicone rubber layer and the fluorine rubber layer is colored black. (4) The composite sheet for resin molding according to claim 1, wherein the fluorine rubber layer is an elastomer made of a polyolefin (co)polymer containing at least one component of a fluorine-containing ethylene unit or a fluorine-containing propylene unit. (5) The composite sheet for resin molding according to claim 1, wherein the composite sheet is used for thermoforming a fiber-reinforced resin sheet or a prepreg sheet in vacuum or under pressure.