JPS6345049A - Sheet material - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of the Invention The present invention relates to gasket materials used in connection parts of chemical piping, etc., which require pressure resistance, heat resistance, and chemical resistance.
Alternatively, the present invention relates to an asbestos-free sheet material that can be used for wind flue duct joints and other industrial applications.

(b) Background of the Invention Conventionally, materials made of a single fluororesin have been used as sheet materials such as gasket materials, but this fluororesin has low pressure resistance and tends to creep when subjected to high loads for long periods of time. This phenomenon (a phenomenon in which strain increases over time for a given stress) causes stress relaxation, which has the disadvantage that, for example, in the case of gaskets, sealing performance deteriorates.

In order to compensate for this drawback, inorganic fibers and carbon powder are filled, but there is a limit to the improvement of properties, and stress relaxation due to the creep phenomenon is unavoidable in areas that are subjected to long-term high loads, so they cannot be used for general purposes. I could not do it.

(c) Purpose of the invention This invention not only has excellent pressure resistance and penetration leakage resistance, but also has excellent heat resistance, chemical resistance, and solvent resistance, and is applicable not only to gasket materials but also to duct joints for flue pipes. The objective is to provide a basic asbestos-free sheet material that can be used as bellows, stringing material, packing material, etc.

(d) Structure of the invention This invention comprises about 70% by weight of phenolic BA fibers and
A sheet material formed by impregnating a base fabric made of a blended fiber with 0% by weight of aromatic polyamide fibers with a fluororesin dispersion, and firing and pressurizing the base fabric at a temperature equal to or higher than the melting point of the fluororesin. It is characterized by

(E) Effects of the Invention According to this invention, the phenolic fibers that make up the base fabric described above do not emit flames or burn out, and the parts that receive heat turn into carbon fibers and create a black stain. It has excellent properties such as not only does not ash, but also does not melt at all, retains its strength even at high temperatures, and does not decompose and generate harmful gases. ing.

In addition, the aromatic polyamide fibers that make up the base fabric are heated to 500°C.
It does not scorch, has self-extinguishing properties, and does not melt.
Furthermore, it has excellent properties such as high tensile strength at high temperatures.

Therefore, the tensile strength and low elongation of the base fabric of the sheet material further enhances the pressure resistance of the fluororesin and increases the mechanical strength of the fluororesin, which reduces the degree of creep of the fluororesin under high loads. When used as a gasket, it maintains stable sealing performance over a long period of time without relaxation.

Furthermore, the heat resistance (flame resistance) of the base fabric and the heat resistance of the fluororesin combine to create an asbestos-free sheet material with even better heat resistance.

In particular, aromatic polyamide fibers become slightly softened during firing and pressurization at temperatures above the melting point of the fluororesin, and the ice version of the fluororesin fills the spaces in the phenolic fiber bundles that are not impregnated and prevents leakage paths. Since it is sealed, seepage leakage of the sheet material is greatly reduced.

Furthermore, by firing and pressurizing, the carbon content of the base fabric becomes 80% or more, and chemical resistance is improved, and an asbestos-free sheet material with excellent chemical resistance can be obtained.

Next, referring to the blending ratio of phenolic 1aIi and aromatic polyamide fiber, when impregnating a blended base fabric with a fluororesin dispersion, the phenolic fiber has non-compatibility (repulsion), and the aromatic polyamide Since these fibers have affinity, it is necessary to increase the amount of aromatic polyamide fibers in order to completely fill the base fabric with the above dispersion.

On the other hand, phenolic 1-fiber has ri1 benign properties and chemical resistance, and carbonizes when fired, so the surface! It is an excellent material with a low coefficient of friction, and in order to make use of this property, it is better to use as little amount of the above-mentioned aromatic polyamide fiber as possible.

From the above points, the appropriate blending range for gaskets and other sheet materials is 60 to 80% phenolic fiber, 140 to 20% aromatic polyamide, and the optimal blending value is approximately 70% by weight 8R% phenolic fiber, 140% to 20% aromatic polyamide. Approximately 30% by weight of polyamide fibers.

(f) Examples of the invention An embodiment of the present invention will be described in detail below based on the drawings.

In FIG. 1, a sheet material 1 is a woven fabric 2 made by d-spinning of 70% by weight phenolic fibers and 30% by weight aromatic polyamide fibers, and a dispersion of fluororesin 3 (an aqueous dispersion of fluororesin). A plurality of impregnated single component materials 4 are laminated and then baked and pressed at a temperature higher than the free rotation temperature of the fluororesin 3 to form an integral structure.

The phenolic fibers that make up 70% of the above-mentioned woven fabric 2 have flame retardant properties, such as not emitting flames but not burning out, and parts that receive heat turning into carbon fibers, producing black burnt marks but not turning into ash. It has excellent properties such as not melting at all, maintaining high strength even at high temperatures, and not decomposing and producing harmful gases.

In addition, the aromatic polyamide fibers that make up 30% of the woven fabric 2 do not burn up to 500 degrees Celsius, have self-extinguishing properties that do not propagate combustion, do not melt, and have high tensile strength at high temperatures. It has excellent properties.

Therefore, the tensile strength and low elongation of the woven fabric in the sheet material further enhances the pressure resistance of the fluororesin 3 and increases the mechanical strength of the fluororesin, which reduces the degree of creep of the fluororesin 3 under high loads. When used as a gasket, there is no relaxation and maintains stable sealing performance over a long period of time.

Furthermore, the heat resistance (flame resistance) of the woven fabric 2 and the heat resistance of the fluororesin combine to provide an asbestos-free sheet material with even higher heat resistance.

In particular, aromatic polyamide fibers become slightly softened during firing and pressurization at a temperature higher than the melting point of the fluororesin 3, and the fluororesin dispersion fills the spaces in the phenolic fiber bundles that are not impregnated, resulting in leakage paths. Since we will block the
Significantly reduces seepage leakage of sheet materials.

Furthermore, by firing and pressurizing, the carbon content of the woven fabric was reduced to 8.
The chemical resistance has been improved to 0% or more, making it an asbestos-free sheet material with excellent chemical resistance.

Next, an example of the manufacturing process for the above-mentioned sheet material will be explained based on FIG. 2.

The strip-shaped woven fabric 2 wound around the roll A is pulled out and passed through an impregnating tank B containing a fluororesin dispersion to be impregnated with the fluororesin dispersion, and then placed in an electric furnace C heated to about 300°C. to carbonize the woven fabric 2.

This results in a single component material.

This single constituent material is cut to desired dimensions as needed,
Several sheets of this single constituent material were laminated and heated at 350°C and 30K.
9/C! Firing and pressurization may be performed under the conditions of i.

In the above examples, a woven fabric made of warm spun yarn of phenolic fibers and aromatic polyamide fibers was used as the base fabric.
As shown in Figure 3, it is phenolic! It is also possible to use a non-woven fabric 5 such as felt made of 1-fiber and aromatic polyamide-based 1fi-rich.

The single component material 4 may be formed into a sheet material by simply firing it as a single component without layering it.

Furthermore, as shown in FIG. 4, as the half-layer constituent material 4 to be laminated, there are two types: one using a woven fabric 2 made of phenolic fibers and aromatic polyamide fibers as a base fabric, and the other using a non-woven fabric 5 as a base fabric. A sheet material may be formed by laminating alternately and integrally firing and pressing the layers.

Note that when forming the sheet material shown in the above examples, by laminating fluororesin sheets, a sheet material with even better chemical resistance and solvent resistance can be obtained.

As shown in the examples above, the sheet material of the present invention is produced by impregnating a base fabric made of a blended fiber of 70% phenolic fiber and 30% aromatic polyamide fiber with a dispersion of a fluororesin. Because it is formed by firing and pressurizing at temperatures above the melting point, the base fabric made of a blend of phenolic fibers and aromatic polyamide fibers and the fluororesin are integrated, and the base fabric increases the pressure resistance of the fluororesin. It is possible to improve properties, reduce creep caused by compression, prevent stress relaxation when compressed, and obtain stable sealing performance over a long period of time.

Moreover, the phenolic fibers and aromatic polyamide fibers that make up the base fabric have flame retardant properties, and together with the heat resistance of fluororesin, they have excellent heat resistance. This is an asbestos-free sheet material that can be used as a basic material for industrial applications.

In particular, in the present invention, a fabric made of a blend of phenolic m1It and aromatic polyamide fibers is used as the base fabric, and when the base fabric is fired and pressurized, the aromatic polyamide fibers are slightly softened and the phenolic Since it fills the spaces within the fiber bundles, an asbestos-free sheet material with significantly reduced percolation leakage can be obtained.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, FIG. 1 is a sectional view of a sheet material, FIG. 2 is a manufacturing process diagram of the sheet material, FIG. 3 is a sectional view of a sheet material showing another embodiment, and FIG. 4 is a sectional view of the sheet material. The figure is a sectional view of a sheet material showing still another embodiment.

Claims (1)

[Claims] 1. A base fabric made of a blend of about 70% by weight phenolic fibers and about 30% by weight aromatic polyamide fibers is impregnated with a fluororesin dispersion, and the base fabric is fired at a temperature equal to or higher than the melting point temperature of the fluororesin. A sheet material characterized by being formed under pressure.