JPS5828056A - Complex gasket - Google Patents

Abstract

PURPOSE:To provide a complex gasket which is excellent in sealing and has high compressive strength and tensile strength by forming a multilayer with alternately piling prepreg made of a thick basa cloth which has a low driven density (number of warps/inch) and heat-resisting property and prepreg made of a thin base cloch which has a high driven density and heat-resisting property. CONSTITUTION:An impregnant is formed by dispersing solid ratio 5-50% of FEP or PFA ultrafine powder in PTFE dispersion or by mixing the powder with PTFE dispersion. On the other hand, base clothes 3, 4 are respectively formed of a heat-resisting cloth such as glass cloth or carbon cloth, one base cloth 3 being formed with driven density changed at the ratio of 1.5-2.5 in comparison with the other base cloth 4. The base clothes 3, 4 are impregnated with the above impregnant to form prepreg. A plurality of prepreg piece of the thin base cloth 3 with high driven density and prepag piece of the thick base cloth 4 with low deiven density are alternately piled up in layers, so as to locate prepreg of the thin base cloth 3 with high driven density disposed on the outermost side.

Description

DETAILED DESCRIPTION OF THE INVENTION The wood i+ relates to a composite gas nut used for heavy-pressure gas nuts or 11-purpose gas nuts.

Generally, a prepreg is made by impregnating glass cloth or carbon cloth with PTFE dispersion or FEP dispersion alone, and then stacking them and heating them to a temperature higher than the melting temperature while applying pressure with a hot plate press. Gaskets molded into plates have been known for a long time.

However, products made from P 'I' F E dispersion alone have poor sealing properties and are unsuitable as sealing materials for gases, while products made from FEP dispersion have good sealing properties but are very expensive materials. High temperature strength is P
In the case of TFE, the disadvantage was that it was also weak.

In addition, in order to improve sealing properties, the base fabric was made extremely thin so that there was no unevenness in the impregnated Gripreg, so it was necessary to cover all the base fabrics, resulting in high costs). It was unsuitable for use in high-pressure piping 7-lunge because of its low resistance.

Therefore, the present invention alternately overlaps prepregs made of a thick heat-resistant base fabric with a low batting density and a thin heat-resistant base fabric with a high batting density (number of warp threads/inch). By laminating and integrating, it is intended to provide a composite gas terra l-' with not only excellent sealing properties but also high compressive strength and tensile strength.

An embodiment of the present invention will be described below in detail with reference to the drawings.

In the composite gasket 1 shown in the drawing, 2 is an impregnating agent, which is made by dispersing ultrafine powder of FEP or PFA in a PTFE dispersion at a chemical proportion, that is, a solid content ratio of 5 to 50 wt%, or completely mixing the dispersion. It is something.

When forming the seam, one base fabric 8 is driven into the other base fabric 4.
f (number of warp threads/inch) 'e It has a good ratio of 1.5 to 2.5, and is impregnated with a composite agent and shaped into a prepreg, and is made with a thin base fabric 8 of 1 ribleg with good implant density. Gripregs each made of thick base fabric 4 with low driving density?
M number of fabrics are alternately stacked so that the prepreg of thin base fabric 8 with low implant density is located on the outermost side.

Then, the laminated Gripreg of base fabric 8.4 is laminated and molded using a hot plate press at a temperature of 340 to 890°C (PTFE gelling temperature) and a molding specific force of 5 to 20 kg/d.

If the tensile strength or compressive strength of the thick base fabric 4 is poor, it is best to combine it with a soft material such as a thin base fabric 3-layer carbon fiber m (low crystal treated product).

A single composite gasket constructed as described above is overlaid on both sides of a thick base fabric 4 with a small implant density on a thin base fabric 81 with a high implant density, and the thin base fabric 8 allows the thick base fabric 4 to be stacked on both sides. Impregnating agent 2 completely eliminated the impregnating failure inside the fiber = 1b.
In addition, the uneven texture of the thick base fabric 4 is covered and smoothed by the thin base fabric 8, resulting in a gastite that is uniformly impregnated in various places.

Therefore, when this multiple gasket 1 is tightened with 7 lunges, uniform blood pressure can be obtained in all parts, and there is no penetration leakage or contact surface leakage.
A perfect seal can be achieved with low tightening surface pressure.

The excellent sealing properties can also be compared in the experimental results shown in FIG.

The composition of the composite gasket used in this experiment is shown in the table below.

Composition As shown in the above examples, the composite gasket of the present invention is made by impregnating a thin base fabric with an impregnating agent and then alternating I/C.
Overlapping, outermost 'ff: Prepreg made from thin base fabric, which is pressure molded at gelling temperature, so the impregnant melts at the gelling temperature and penetrates finely between the fibers of the base fabric. It can be impregnated into even the most oily voids, and the unevenness of the weave of the thick base fabric is eliminated by the thin base fabric.It can be impregnated uniformly throughout the entire track, can be constructed into a smooth shape, and can obtain uniform tightening surface pressure. Excellent sealing properties can be obtained by adding FEP or PFA to the impregnating agent.

What's more, the thick composite gasket uses a thick base fabric for pressure? The sheath has a high tensile strength and uses a heat-resistant base material, so it can be used as a gasket for temperature 1 and pressure.

In addition, since a thick base fabric is used between thin base fabrics, the number of base fabrics used can be made larger than when the entire kf4 is made of hand base fabrics. Material costs can be reduced.

[Brief explanation of the drawing]

Fig. 1 and Fig. 2 show all examples of one real element of origin j. FIG. 2 is a partially enlarged sectional view of FIG. 1. FIG. 8 is a diagram showing the sealing characteristics of the composite gasket for Himi. 2... Impregnating agent 8.4... Base fabric 2nd section 5

Claims (1)

[Claims] 1. PTFE dispersion with a solid content ratio of 5 to 5 Qwt
% of FEP or PFA ultra-fine powder bed dispersed or its dispersion completely mixed on the impregnation agent? 1.5
The prepreg is completely formed by impregnating two types of private lids, such as glass cloth or carbon cloth, with a ratio of ~2.5. Adhesive gasket F0 made by stacking layers alternately on both sides of a low base fabric and molding them at the gelling temperature of JPTFE using a hot plate press.