JPS6018705B2 - heat resistant packing - Google Patents

Description

[Detailed description of the invention] The present invention relates to heat-resistant packing.

More specifically, the present invention relates to a heat-resistant packing formed from a sheet obtained from short fibers and pulp made of a heat-resistant aromatic polymer. Conventionally, packings made of rubber, fiber, Teflon, asbestos, etc. are often used in places where leakage prevention is required.

However, since rubber and fiber have poor heat resistance, they cannot be used in high-temperature areas. Furthermore, Teflon, asbestos, and the like have excellent heat resistance, and although Teflon has good corrosion resistance, it is difficult to use at temperatures higher than 150 qo due to its large creep property.

Although asbestos has good heat resistance, its leak-preventing effect is not very good. The inventors of the present invention have conducted intensive research to eliminate such drawbacks, and have found that by using a sheet made of pulp made of a heat-resistant aromatic polymer and short fibers, it is easy to process, has good heat resistance, and leaks. A packing with excellent sealing performance can be obtained, and the present invention has been completed.

That is, the present invention is a heat-resistant packing formed by forming a sheet obtained by making paper from short fibers and pulp made of a heat-resistant, solvent-soluble aromatic polymer, and pressurizing and heating the paper.

The heat-resistant, solvent-soluble aromatic polymer used in the present invention has a softening point of at least 15,500 or more, preferably 25,000 or more, and has a softening point of at least 15,500 or more, preferably 25,000 or more.
It is a polymer whose physical properties do not change significantly even when used in air for a long time at a temperature of 500 q or more, preferably 180 q0 or more, and at least 3% by weight or more, preferably at room temperature, with respect to any organic solvent system. It means a polymer that has a solubility of 7% by weight or more and forms a stable solution.

Aromatic polymer means a polymer in which a considerable portion of the primary mirror consists of aromatic rings, and such polymers have a specific structure,
It is not limited to the manufacturing method. 1 Aromatic Polyamide '11 An amide of a dicarboxylic acid having an aromatic ring, preferably a highly active derivative such as an acid halide, and a diamine having an aromatic ring, such as terephthalic acid, isophthalic acid, etc. as the dicarboxylic acid, and metaphenylene as the diamine. A type of dicarboxylic acid using amine, 4,4'-diaminodiphenyl enal, 4,4'-diaminodiphenylmethane, xylylene diamine, N-methyl-paraphenyl diamine, etc., and a type of homogeneous diamine. It may be a polymer, or it may be a polymeric polymer consisting of two or more compounds of either or both of a dicarboxylic acid component and a diamine component.

Typical examples include polymethaphenylene isophthalamide, polymethaxylene diamine terephthalamide, polyN-methylparaphenylene terephthalamide, or Aoi polymerization polymer of metaphenylene diamine, isophthalic acid, and terephthalic acid. . (1) A polyamide obtained by activating and condensing an aminocarboxylic acid having an aromatic ring. For example, as an aminocarboxylic acid, a homopolymer made of only one type of aminocarboxylic acid such as para- or meta-amino/benzoic acid or para-aminomethylbenzoic acid may be used. Alternatively, it may be a copolymer of two or more types of aminocarboxylic acids.

A typical example is a condensate of para-aminobenzoic acid. '31 Typical examples of polyamides obtained by copolymerizing the above (1} and '2) include polyamides obtained by condensing the three components of metaphenylene diamiso, isophthalic acid chloride, and para-amino acid chloride/benzoic acid chloride hydrochloride.

2 aromatic polyamideimide formula where x is alkylene, alkylidene, cycloalkylene or cycloalkylidene having 1 to 6 carbon atoms,
It consists of a group selected from 1○1, 1S1, 1S021, 1N=N1.

Here, R is an organic group having 1 to 10 carbon atoms, Y, Y
' may be the same or different, and each can include a hydrocarbon group having 1 to 6 carbon atoms, a halogen atom, an alkoxy group having 1 to 3 carbon atoms, an allyloxy group having 1 to 3 carbon atoms (a at least one selected from the group consisting of a carpolkoxy group having 2 to 10 carbon atoms, and an alkoxycarbonyl group having 1 to 5 carbon atoms.
It is one.

m and n may be the same or different, and are 0 to 3.

The polyamideimide of the above formula is composed of at least 70 mol%, preferably 85 mol% or more, and in particular, x is 1 CH2
1, 101, 1S○2 1, Y, and Y' are preferably a methyl group, a halogen atom, or a methoxy group, and m and n are preferably 0 or 1. The polyamideimide contains up to 30 mol%, in particular up to 15 mol%, of repeating units.

where R is an alkylene group having 2 to 15 carbon atoms,
(Y is the same as above) or.

Up to 30 mol %, in particular up to 15 mol %, of the repeating units may be polyamidebennimidazole, aromatic polyimides, the aforementioned aromatic polyamides.

In producing the pulp used in the present invention, the above polymer solution alone or a mixture of the solution and inorganic filler fine particles can be used. Various types of inorganic filler fine particles can be considered, and examples thereof include the following.

Examples include mica, asbestos, glass fiber, glass flakes, quartz powder, talc, alumina, calcium sulfate, calcium carbonate, kaolin clay, silica, feldspar powder, magnesium carbonate, and magnesium oxide.

When producing the pulp used in the present invention, a mixed solution may be used in which the inorganic filler fine particles are added to a solution in which the polymer is dissolved, or the inorganic filler fine particles may be mixed together with the raw material and the solvent. , a polymerized solution may also be used.

A method can be applied in which the polymer solution or the polymer solution containing inorganic filler fine particles is introduced into a precipitant in a high-speed rotary machine, and simultaneously subjected to a shearing or beating action while removing the solvent to form a pulp.

The solvent used in the above method is a water-soluble solvent that dissolves the polymer and does not act on the inorganic filler fine particles, such as sulfuric acid, hydrogen fluoride, fuming sulfuric acid, fluorosulfuric acid,
Inorganic solvents such as chlorosulfuric acid and polyphosphoric acid, N-methyl-2
-pyrrolidone, N・N-dimethylformamide, N・N
-Organic solvents such as dimethylacetamide, dimethylsulfoxide, hexamethylphosphoramide, tetramethylurea and the like are preferred.

It is also possible to use a solvent system in which the solubility of the polymer is increased by adding an inorganic salt such as lithium chloride or calcium chloride to the above-mentioned organic solvent.

The concentration of the polymer in the solution varies depending on the type of polymer, degree of polymerization, etc., but is preferably about 2 to 15% by weight.

In producing the pulp used in the present invention, the precipitate is preferably a liquid or solution that is miscible with the solvent of the polymer solution but is a non-solvent for the polymer. Such precipitating agents will vary depending on the type of solvent used.

When an organic solvent is used as a solvent, it may be water alone, glycerin, ethylene glycol, a monohydric glycerin mixture, ether, etc., or an aqueous solution of an organic solvent, or one or two of the salts represented by MKn. An aqueous solution containing the above may be used.

Here, M is Li, Na, K, Mg, Ca, Sr, Ba,
Sn, Zn, AI or Nj, X is CI, N03, Br
, CH3COO or SCN, n is an integer from 1 to 4.

Such salts include calcium chloride, lithium chloride, aluminum chloride, and the like. Calcium chloride-aqueous precipitates are desirable because they are easy to handle and inexpensive.
When an inorganic solvent is used as the solvent, the precipitant is preferably water alone or an aqueous solution of the inorganic solvent. In the present invention, heat-resistant fibers can be used as the fiber component to be used in paper making together with pulp particles.

The weave of such fibers is 0.5 to 10 deniers, and the fiber length is 1
~2 It is desirable that it is an enemy. Various polymers can be used to form such heat-resistant fibers, and examples include the following fibers. 1 Short fiber aromatic polyamide made of aromatic polyamide is the same as above.

2 Short fiber aromatic polyamideimide made of aromatic polyamideimide is the same as above.

3. Short fibers made of aromatic polyether Examples of the aromatic polyether include polyphenylene oxide and polyarylene oxide.

4 Short fiber aromatic polyester made of aromatic polyester: polyethylene-2.6 naphthalate and/or polyethylene-2.6 naphthalate'0} ethylene-2
- Copolymerized polyester containing 85 mol% or more of 6-naphthalate units and/or ethylene-2.7 naphthalate units.

As the English polymerization component of the English polymerization polyester, a copolymerized polyester using an aromatic dicarboxylic acid as an acid component is preferably used.

1... Polyethylene-2,6-naphthalate and/or polyethylene-2,7-naphthalate and/or (ii) Contains 85 mol% or more of ethylene-2,6-naphthalate and/or ethylene-2,7-naphthalate units A mixed polyester containing a copolymerized polyester is polyethylene terephthalate.A mixed polyester containing a copolymerized polyester containing 85 mol% or more of ethylene terephthalate units.

In this case, a copolyester using an aromatic dicarboxylic acid as a brewing component is preferably used as a polymerization component of the copolyester.

N(i} polyamide terephthalate and/or (ii
) Mixed polyester containing English polymerized polyester containing 85 mol% or more of ethylene terephthalate units 5 Short fibers made of inorganic compounds Examples of short fibers made of inorganic compounds include glass fibers, asbestos fibers, rock wool, mineral rod wire, and fused silica fibers. There are whiskers such as inorganic fibers such as , glassy silica fibers, seto fibers, kaolin fibers, porxide fibers, khanite fibers, boron fibers, potassium titanate fibers, and magnesia fibers, alumina, and silicon nitride.

6 Natural fibers As the natural fibers, cellulose fibers, regenerated fibers, and cellulose acetate fibers are preferred.

Such fibers can be used alone or in combination of two or more. In the sheet used in the present invention, the amount of pulp blended is preferably 10 to 9% by weight based on the sheet.

If the blending amount of the above-mentioned pulp is less than 1% by weight, it is not preferable because the physical properties such as strength and elongation of the sheet deteriorate.

Also, if the amount of pulp added is more than 9% by weight, the physical properties such as strength and elongation of the sheet will deteriorate, so it is not preferable.

The sheet obtained as described above can be made into an excellent sheet by heating under pressure using a hot press, a hot roll, or the like after drying.

The temperature at which the pressure is applied varies somewhat depending on the blending ratio of pulp and short fibers, etc., but it is preferably 140 to 32 mm. The pressure to be applied varies somewhat depending on the blending ratio of pulp and short fibers as well as the temperature at which it is applied, but it is preferably 200k9' or less. The heat-resistant packing material of the present invention can be used not only as a packing material to prevent liquid leakage in areas where liquids are used at high temperatures, but also as a cushion or padding paper when heat treatment and hot pressing are performed. Examples of uses include:

A method for measuring the main measured values in the present invention will be explained.

Logarithmic viscosity: Measured at 30% in 95% sulfuric acid or N-methyl-2-pyrrolidone at a concentration of 0.5/l00.

Tensile strength: Measured by the method of JISP 8113, k
9/Represented by a fence.

Tensile elongation: Measured according to the method of JISP 8132 and expressed in %.

Hereinafter, the present invention will be explained in detail with reference to Examples.

Example 1 Polyamideimide obtained from trimellitic anhydride, 4,4'-diaminodiphenylmethane, 4,4'-diphenylmethane diisocyanate (logarithmic viscosity in N-methyl-2-pyrrolidone 0.8) for 5 days and 95 days for N -Methyl-2
- A mixture of kaolin clay and kaolin clay added to a solution containing pyrrolidone was heated at high speed.
% by weight of N-methyl-2-pyrrolidone aqueous solution to obtain pulp.

After thorough washing of the pulp, a fiber obtained by wet yarning from a dispersion of 0.84 mm in water and an N-methyl-12-pyrrolidone solution of polymetaphenylene isophthalamide with a weave of e and stretching. Short fiber 0 cut into 5 lengths
．． The aqueous dispersions prepared after 24 days were mixed and spread on a stainless wire mesh to obtain a sheet.

Such a sheet was dried at 100 qo, 230 qo, 20
The physical properties of the paper heat-pressed at 0 kg' were as follows. Tensile strength: 3k9/Unfavorable tensile elongation: 6%.

When such a sheet is cut into a predetermined shape and size and extruded using the extruder shown in Fig. 1 at 270°C with a screw 1 through a breaker plate 3 and an extruder head 4, No leakage was observed even after 7 hours at pressure look 9/.

On the other hand, when a normally used asbestos packing is used, there are many processing errors during the packing manufacturing process, and even when used as a packing, the sealing is poor and nylon 6 leaks significantly, making it unusable. Furthermore, when paper made of natural cellulose was used as a packing, it leaked within 5 minutes due to its poor heat resistance, making it unusable.

Example 2 In an extruder similar to Example 1, polycarbonate was melt-extruded at a pressure of 200 k9' at a temperature of 30,000, but no leakage of the polymer was observed even after 1 hour.

Example 3 A solution containing 60% of the same polyamideimide as in Example 1 in 94% of N-methyl-2-pyrrolidone was prepared by adding 67% by weight of N-
A pulp was obtained by introducing the mixture into an aqueous solution of methyl-2-pyrrolidone.

This pulp was made into paper with polymetaphenylene-sophthalamide short fibers in the same manner as in Example 1, and a sheet obtained was hot-pressed.

This sheet is cut into a predetermined shape and size, and 270
It was used for the packing 2 of the pent part of a nylon 6 extruder at midnight, but no leakage was observed even after 6 hours at a pressure of 100 k9/m.

Example 4 A 7% by weight solution of polymetaphenylene isophthalamide in N-methyl-2-pyrrolidone was introduced into an aqueous solution of 3% by weight in N-methyl-2-pyrrolidone under a high-speed rope and precipitated to obtain pulp. .

After thoroughly washing the pulp with water, polymetaphenylene isophthalamide short fibers (weaving degree: e, fiber length: 5) and pulp 6.
The paper was made in a proportion of 4% by weight of short fibers and 4% by weight of short fibers.

After drying this sheet, it was hot pressed at 300 qo.

This sheet was cut into a predetermined shape and size, and used as the packing 2 of the pen section of the extruder of Example 1.
In this C, polyethylene terephthalate was melt extruded.

No polymer leakage was observed even after 5 hours of use at a pressure of 200k9/cm.

[Brief explanation of drawings]

FIG. 1 shows an example of an apparatus to which the heat-resistant packing of the present invention is applied. In FIG. 1, 1 is the screw of the extruder, 2 is the heat-resistant packing of the present invention, 3 is the breaker plate, and 4 is the head or tie of the extruder.

Claims (1)

[Claims] 1. A heat-resistant packing made by molding a sheet made of pulp and short fibers made of a heat-resistant, solvent-soluble aromatic polymer and heated under pressure.