JPH06170978A - Production of fluoroplastic laminate - Google Patents

Abstract

PURPOSE:To enhance the bonding strength with glass cloth and to uniformize the thickness of a laminate by extruding molten fluoroplastic on the glass cloth from an extruder to integrate with the glass cloth under pressure. CONSTITUTION:When a plurality of glass cloths are used, weighed molten fluoroplastic is extruded on the glass cloth positioned at the central part and glass cloths and separately prepared fluoroplastic films are alternately arranged on the central glass cloth. A metal foil is arranged to the upper surface and/or rear surface of the outermost part as necessary to perfomt integrating processing. As fluoroplastic to be used, one not capable of flowing without being thermally decomposed at the time of melting under heating is suitable and, as a concrete example, there is a tetrafluoroethylene/perfluoroalkylvinyl ether copolymer. As a concrete example of glass cloth, there is electric alkali free glass cloth or high strength glass cloth and the structure of the glass cloth is formed by plain weaving, twill or satin weave.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a fluororesin laminate, and more particularly to electrical equipment, electronic equipment, communication equipment,
The present invention relates to a method for producing a fluororesin laminate suitable for chemical equipment, building materials and the like.

[0002]

Fluorine resin is used in a wide range of fields because it is excellent in heat resistance, chemical resistance, electric insulation and water repellency. However, since the fluorine resin itself is soft, it is reinforced with an inorganic filler to compensate for this property. Among the inorganic fillers, glass cloth is inexpensive and therefore is often used, and the laminated body reinforced with glass cloth has excellent electrical characteristics, and is therefore particularly often used in the electrical field. Furthermore, it is also used as a large-scale construction sheet by coating the surface of glass cloth with fluorine resin.

Conventionally, for these laminated bodies, a method of impregnating glass cloth with a fluorine resin liquid and then sintering at a high temperature of 350 to 400 ° C. is used. According to this method, a high temperature firing apparatus is used. However, there is a problem that a thin glass cloth is used to impregnate the resin liquid, and a large number of these are laminated and sintered by the batch method to be integrated.

Further, a method is known in which a fluorine resin film and a glass cloth are alternately laminated and molded under high temperature heating and pressing, but the processing cost is high, and the thicker the laminated body, the more the laminated body. There was a problem that the thickness of the inside glass cloth became uneven. Further, a method is known in which a fluorine resin film and a glass cloth are continuously processed by using a double belt press molding machine having endless belts which are paired up and down (for example, JP-A-1-137727). However, this method melts the fluorine resin film by heat conduction from the heated belt and integrates it with the glass cloth.However, this method melts the fluorine resin film by heat conduction, so It was not possible to raise the speed and the efficiency of energy consumption was poor, making it difficult to put it to practical use on an industrial scale.

[0005]

In view of such a situation, the present invention is directed to the production of a fluororesin laminate having a high adhesive strength with a glass cloth and capable of efficiently obtaining a laminate having a uniform thickness. The purpose is to provide the law.

[0006]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that when a continuous integrated processing method such as a double belt press molding machine is used, heat melting from an extruder is performed. Fluorine resin is extruded on a glass cloth,
The inventors have found that the above problems can be solved by continuously performing an integrated treatment under pressure with a heating belt, and arrived at the present invention.

That is, according to the present invention, a molten fluororesin is extruded from an extruder onto a glass cloth, and the glass cloth and the fluororesin are integrated under pressure to produce a fluororesin laminate. The law is the gist.

The present invention will be described in detail below. First, in the present invention, as the fluorine resin, a resin that can flow without being thermally decomposed during thermal melting is used. As such a fluorine resin, one having a melting point of 250 ° C. or higher is preferable, and for example, a tetrafluoroethylene-perfluoroalkylvinylether copolymer (hereinafter referred to as PFA) or a tetrafluoroethylene-hexafluoropropylene copolymer (hereinafter referred to as FEP). ,), Tetrafluoroethylene-hexafluoropropylene-perfluoroalkyl vinyl ether copolymer (hereinafter referred to as EPE), and the like. As such a fluorocarbon resin, a fluorocarbon resin having a melt viscosity at 350 ° C. of 10 ⁴ to 10 ⁷ poise is preferable.

Next, as the glass cloth, E glass (alkali-free glass for electricity), S glass (high-strength glass), D glass, quartz glass, silica glass (low dielectric glass), C glass (chemical alkali-containing glass) Examples of the glass cloth include glass).

Further, the single fiber diameter of the glass fiber constituting the glass cloth used in the present invention is preferably 3 to 15 μm. If the diameter of the single yarn is smaller than 3 μm, it tends to be broken and the handling tends to be difficult. On the other hand, when it exceeds 15 μm, the surface smoothness of the obtained laminate may be deteriorated. The thickness of the glass cloth is preferably 20 to 250 μm. When the thickness of the glass cloth becomes thinner than 20 μm, the strength of the glass cloth becomes weaker and the surface treatment,
It tends to be difficult to handle in the molding process. On the other hand, when the thickness of the glass cloth exceeds 250 μm, it is necessary to use a glass fiber having a large fiber diameter in order to secure the thickness, so that the surface smoothness of the obtained laminate tends to be deteriorated and the coupling agent treatment At this time, it tends to be difficult for the glass fiber to be impregnated, and when the fluorine resin and the glass cloth are integrated, the molten fluorine resin may not easily enter the glass cloth.

The structure of the glass cloth is not particularly limited, such as plain weave, twill weave, satin weave, triaxial weave, and knit,
A plain weave is particularly preferable from the viewpoint of dimensional stability.

In the present invention, the molten fluorocarbon resin is extruded from the extruder onto the glass cloth, and the glass cloth and the fluorocarbon resin are integrated under pressure. A method of continuously treating using a double belt press molding machine having a function of heating compression and cooling compression is preferable. At this time, when the number of glass cloths sent to the double belt is one, the molten fluororesin resin measured from the extruder adjacent to the glass cloth is supplied, and further, if necessary, to the upper surface and / or the lower surface. A metal foil or the like is placed and integrated processing is performed.

When a plurality of glass cloths are used, the weighed molten fluorine resin is extruded on the glass cloth located at the center, and the glass cloth and a separately prepared fluorine resin film are alternated outside thereof. And further, a metal foil or the like is arranged on the uppermost surface and / or the lowermost surface of the outermost part to perform integration processing. In this case, by extruding the molten fluorocarbon resin to the central part, the heat from the heated double belt and the latent heat of the hot-melt resin in the central part
A more uniform and rapid thermal compression integration process becomes possible.

The heating and pressurizing condition of the double belt is 300 to
It is preferably 10 to 50 kg / cm ² at 400 ° C. for 1 to 10 minutes.

The laminate thus obtained is preferably used for various purposes. In addition, by arranging this laminated body and metal foil as required, heat bonding and heat treatment are performed using a multi-stage press, a double belt, a mold, etc., and a higher-order laminated body having various functions and various shapes are provided. It is possible to make a laminated body such as a component, a thick laminated plate or the like.

[0016]

EXAMPLES The present invention will be specifically described below with reference to examples.

Example 1 A so-called heat cleaning glass cloth (116T, manufactured by Unitika Ltd.) obtained by heat-treating a spinning paste and a warp paste.
Single yarn diameter: 7 μm, Weaving density: 60 warps / 25 mm, weft 5
Coupling agent (manufactured by Toray Silicone Co., Ltd., 8 pieces / 25 mm) containing N-β- (N-vinylbenzylaminoethyl) -γ-aminopropyltrimethoxysilane as an active ingredient.
SZ6032) to obtain a surface-treated glass cloth (thickness 100 μm). FEP resin (melt viscosity 1 × 10 ⁵ poise) melted at a temperature of 350 ° C by a melt extruder is sent from a slit nozzle to a double belt press molding machine (belt speed 1 m / min.) Heated to a temperature of 290 ° C. The glass cloth was metered and supplied so as to have a thickness of 250 μm. Pressure between double belts 20kg / cm ²
It was hot-pressed for 2 minutes and then cooled by a double-belt press controlled to room temperature to obtain a laminate having a thickness of 0.3 mm.

Example 2 In Example 1, copper foil having a thickness of 18 μm was supplied to the heated double belt press, glass cloth was placed on the copper foil, and FEP melted to a thickness of 250 μm was formed on the glass cloth. And a copper-clad laminate (thickness: 0.33 mm) were obtained in the same manner as in Example 1.

Example 3 In Example 2, copper foil, glass cloth and molten FEP were used.
In addition, a glass cloth and one FEP resin film each having a thickness of 250 μm are arranged, the double belt temperature is set to 330 ° C., and the others are the same as in Example 1 and the copper-clad laminate (having a thickness of 0.6) is used.
mm).

Comparative Example 1 The surface-treated glass cloth of Example 1 and a thickness of 250 μm
m FEP resin film was fed to a double belt press machine (speed 1 m / min.) heated to a temperature of 290 ° C., and heat-compressed between the double belts at a pressure of 20 kg / cm ² for 2 minutes, and subsequently controlled to room temperature. It was tried to obtain a laminate having a thickness of 0.3 mm by cooling with a double belt press, but the glass laminate and the FEP resin film were peeled off, and the intended laminate could not be obtained.

Comparative Example 2 The surface-treated glass cloth of Example 1 was applied to a thickness of 125 μm.
Sandwiched between 2 sheets of FEP resin film, and supplied to a double belt press machine (speed 0.1 m / min.) Heated to a temperature of 350 ° C., and heat-compressed between the double belts at a pressure of 20 kg / cm ² for 10 minutes, Then, it cooled with the double belt press machine controlled to room temperature, and obtained the laminated body (thickness 0.3mm).

COMPARATIVE EXAMPLE 3 In Example 2, glass cloth and F having a thickness of 250 μm were used.
Each 2 sheets of EP resin film are laminated alternately, and further, a copper foil of 18 μm is placed on the outermost layer of the laminated body, and a double belt press machine (speed 1 m / min.) Heated to a temperature of 350 ° C. is used between the double belts. At 20 kg / cm ² for 2 minutes, followed by cooling with a double belt press controlled at room temperature to obtain a copper-clad laminate (thickness 0.6 mm).

Table 1 shows the evaluation results of the obtained laminate. The method for evaluating the characteristics of the laminate is as follows. (1) Water absorption rate Accurately measure the weight of the laminate before and after the moisture absorption treatment (Prestiac Kutzker test, temperature 121 ° C, 1 hour) to 1 mg with a direct reading balance L-200SM type (manufactured by Shimadzu Corporation). Weighed and calculated from the weight difference. (2) Solder heat resistance After the laminate was subjected to a moisture absorption treatment (Prestiac Kutker test, temperature: 121 ° C, 1 hour), it was immersed in a solder bath at 260 ° C for 30 seconds, and the presence or absence of blistering was visually evaluated. ○: No abnormality △: Partially blistered ×: Blistered entirely

(3) Energy cost index = heating dowel belt temperature (° C.) / Resin melting point (270 ° C.) × heating double belt processing time (minutes) / reference processing time (1 minute)

[0025]

[Table 1]

[0026]

According to the present invention, it is possible to efficiently obtain a uniform fluororesin laminate having a high adhesive force with a glass cloth.

Claims (1)

[Claims] 1. A method for producing a fluororesin laminate, which comprises extruding a molten fluororesin onto a glass cloth from an extruder and integrating the glass cloth and the fluororesin under pressure.