JPS60212476A - Packing material - Google Patents

Abstract

PURPOSE:To provide a packing material having excellent capability to hold a sealant irrespective of the absence of asbestos fiber, and having excellent sealing property, by blending fibers other than asbestos fiber with fibrillated aromatic polyamide fiber. CONSTITUTION:The objective packing material can be prepared by blending (A) arbitrary conventional fiber other than asbestos fiber (e.g. flame-retardant polyacrylonitrile fiber, aromatic polyamide fiber, phenolic resin fiber, etc.) with (B) fibrillated aromatic polyamide fiber (preferably mechanically or chemically fibrillated pulp having a specific surface area of >=1.0m<2>/g).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a packing material for constructing a packing that does not use asbestos, that is, an asbestos-free packing.

Conventional packing materials often use packing materials made of asbestos fibers. This is because asbestos has excellent wear resistance and thermal stability, and
Since asbestos fibers can be obtained with small fiber diameters, a packing material made of such fibers can hold packing materials such as grease or lubricating oil well, and therefore a packing material with excellent sealing properties can be obtained.

However, since asbestos tends to generate dust when handled, it is not hygienic for those involved in packing materials and packing manufacturing. In particular, asbestos dust is said to cause occupational diseases such as lung cancer, asbestos disease where asbestos dust is deposited on the lungs and skin, and mesothelioma if inhaled over a long period of time. There is also a strong demand for the development of so-called asbestos-free packing that does not use asbestos.

For this reason, it has been proposed to use packing materials made of organic fibers, and although there are some differences depending on the type of organic fibers, even if alumina fibers such as This is because the fiber diameter of machine fibers cannot be made very small.

There was a problem in that the packing material had poor retention of the filling material as described above, and the packing performance was inferior to 11J compared to when asbestos fiber T-fiber was used. In order to solve this problem, attempts have been made to make the surface of the padkin fluffy, or to use a material that has a relatively high ability to retain the eye material for part of the padkin knitting yarn. However, this is far from a fundamental solution to the above problem.

The present invention has been made in view of these circumstances, and provides a packing material that has substantially the same packing material retention properties as packing materials made of asbestos fibers, despite not using asbestos fibers. This aims to improve the sealing properties of asbestos removal hacking.

The packing material of the present invention that solves this problem is made by blending appropriate regular fibers excluding asbestos with fibrillated aromatic polyamide fibers.

That is, as the normal fibers, one or more types of fibers MFtl can be appropriately selected and used from among fibers other than asbestos m-fibers. For example, polyacrylonitrile flame-resistant fibers, aromatic polyamide fibers such as DuPont's Kevlar, phenolic resin fibers, tetrafluoroethylene resin fibers, carbon fibers, rayon, hemp, cotton, etc. Cotton-like fibers of 10 mm or more are used.

In addition, fibrillated aromatic polyamide fiber # (hereinafter referred to as "Aramid fiber #J") is a pulp-like material obtained by mechanically or chemically refining aramid fiber, and its specific surface area is 1.om'/ g or more is used.

For example, "Kevlar" pulp manufactured by DuPont is used. This is highly fibrillated, with an average fiber length of 2 mm or 4 mm, and a specific surface area of 8 to 10 g/g.

By the way, fibrillated aramid fibers are
The diameter is extremely small, and the specific surface area is extremely large (for example, 0.2 m'/g for Kevlar J Chopped-Fi made by DuPont with a fiber length of 6 mm).
Because it is a material, it can hold packing materials such as grease and lubricating oil well, but on the other hand, the fiber length is extremely short (generally 2 to 5 mm), so depending on the normal spinning method, it cannot be knitted into a packing material. Spinning it into thread is something that cannot be achieved.

In the present invention, by blending fibrillated aramid fibers, which cannot be spun alone, with one or more types of M&IT, that is, stable,
The purpose of the present invention is to provide a packing material made of a 4J co-spun two-way packing yarn that can be easily removed even in a normal spinning method.

Therefore, by blending the fibrillated aramid fiber Mt, the packing material of the present invention has an excellent [1-crystalline material retention property] that is almost the same as that of the packing material made of asbestos fiber.

The blending ratio (weight ratio) of fibrillated aramid fibers in the punkin material, that is, the blended yarn of the present invention is 15 to 90.
% is desirable. This is because when 90% fcM increases, in other words, the stable spinning rate (weight ratio 1j) increases.
When the ratio of stable spinning is less than 105, the tenacity (strength) of the blended yarn decreases and becomes less than 15%. In other words, when the stable blending ratio exceeds 8.5%, the tenacity of the 41d spun yarn increases. However, there is a problem with the meltability of the fibrillated aramid fiber ME, and excellent packing material retention cannot be obtained. This is also clear from the graph in FIG. 1, which is the result of measuring the strength of the blended yarn with respect to the mixing ratio (weight ratio) of the stable in which the blended yarn has a diameter of 1 mm. In FIG. 1, a solid line indicates a stable made of aramid fiber, a broken line indicates a stable made of rayon, and a chain line indicates a stable made of polyacrylonitrile fiber.

As described above, the packing material of the present invention has excellent packing material retention properties even though it does not use asbestos fibers. This makes it possible to provide asbestos-free packaging that has superior sole performance compared to regular packaging.

This will become clearer from the experimental examples described below.

(Experiment example) Polyacrylonitrile flame-resistant fiber (30% by weight), which is a regular fiber, and "Kevlar" pulp made by DuPont, which is a fibrillated aramid fiber (70% old IJ by weight), are blended using a regular spinning method. Using the obtained blended yarn, the surface was treated with grease and graphite, and a large number of yarns were gathered together to form a knitting yarn, which was then knitted at an angle to obtain Patsukin ■. Using only polyacrylonitrile flame-resistant #, Patsukin II was obtained in the same manner as above.

Furthermore, using only phenolic resin fibers, remove the packing ■ in the same manner as above.

Incidentally, all of the above-mentioned pankins (1) to (2) have an inner diameter of 32 mm and an outer frame of 48 mm.

Then, calculate the amount of leakage from each pankin 1 to
When the measurement was carried out under the conditions of 11 circumferential speed of 6 m/sec, the following results were obtained.

In other words, with Punkin I, the leakage amount was only 30 to 40
cc/min, had the required sealing properties, and could be adjusted for additional tightening.

On the other hand, with Patsukin II, the leakage amount is 700~
800cc/min, and 400cc/min for Pa-Nkin■
'600 cc/min. Moreover,
Grease for both Packins II and III.

The retention property was poor, and as time passed, most of it flowed out and the sealing performance was lost.

Therefore, from the results of this experiment, it can be concluded that Packin I, which uses the packing material of the present invention, can exhibit superior sealing properties compared to the conventional Asth removal packing materials II and I. will be understood.

The punching material of the present invention is suitably used not only for grease-impregnated packings but also for tetrafluoroethylene resin-impregnated packings, etc., and the surface treatment of the blended yarn is optional.

[Brief explanation of drawings]

FIG. 1 is a graph showing the relationship between the blending ratio (weight ratio) of stable and the strength of the blended yarn in the packing material according to the present invention. Patent applicant: Nippon Pillar Industries Co., Ltd. Agent: Takashi Suzue, patent attorney

Claims (1)

[Claims] A packing material made by blending appropriate ordinary fibers other than asbestos fibers with fibrillated aromatic polyamide fibers.