JPH045492A - Seal member in scroll compressor or vacuum pump - Google Patents

Abstract

PURPOSE:To improve the heat resistance, fleon gas resistance and productivity of seal member by using thermotropic liquid crystal polymer including a predetermined monomer unit and glass carbon having a predetermined weight loss property in air for essential components. CONSTITUTION:A seal member 1 engaged in an end surface of a scroll member 3 is formed of a polymer composition consisting of essential components of 90-50wt.% thermotropic liquid crystal polymer and 10-50wt.% glass carbon. The thermotropic liquid crystal polymer includes at least a monomer unit expressed by an expression I. For the glass carbon, a broken-cut surface of the particle has a gloss like glass, and its weight loss is less than 5wt.% when it is kept in air at 350 deg.C. The heat resistance and fleon-gas resistance thus become good, and the productivity is improved because it can be injection moulded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improved sealing member for a scroll-type pressure machine or vacuum pump.

[Prior art] A scroll-type pressure machine has a pair of scroll members arranged so as to mesh with each other, one scroll is fixed, the other does not rotate, but revolves at a constant radius, and is surrounded by both scroll members. This compresses the gas by moving the empty space to the center and shrinking it. Furthermore, in a scroll-type vacuum pump, the relative rotation between the fixed and movable scrolls is opposite to that of a compressor.Normally, the materials of these scroll members are aluminum alloy, steel, etc. metal materials are used.

That is, in a scroll compressor or a vacuum pump, it is extremely important to improve the sealing performance of the sliding portion between both scroll members, and seal members are fitted into the end faces of both scroll members.

Therefore, the performance required of such a sealing member includes not only sealing performance but also slidability such as wear resistance, heat resistance, creep resistance, chemical resistance, etc. In other words, extremely harsh conditions are required for normal sliding conditions.

Conventionally, such sealing members have mainly been made of polytetrafluoroethylene resin with various fillers added thereto. For example, JP-A No. 63-158362 describes a method for improving the abrasion resistance and creep resistance of tetrafluoroethylene resin by adding organic fillers and injection moldable fluorocarbon resin to tetrafluoroethylene resin. Disclosed. However, injection molding is not possible for compositions whose main component is tetrafluoroethylene resin, and the desired product must be obtained by punching out a compression-molded flat plate, resulting in poor productivity and, of course, high product costs. It's expensive and undesirable.

In order to solve this problem, JP-A No. 62-223488 discloses an injection moldable sealing member whose main components are aromatic polyetherketone resin, polyarylene sulfide resin, and polyetherimide resin. 63-15
Japanese Patent No. 8362 proposes an injection moldable sealing material containing an aromatic polyetherketone resin as a main component.

However, these resins are still insufficient in terms of heat resistance at high temperatures during operation of a compressor or vacuum pump, or resistance to fluorocarbon gas of the refrigerant used in the compressor.

In addition, the spiral sealing member of a scroll compressor or vacuum pump has a small cross-sectional area and a long product length, as shown in Figure 1, so it is difficult to perform injection molding with conventional resin due to its fluidity. There was a problem that it was not sufficient and difficult to mold.

Furthermore, the sliding property was also insufficient.

[Problems to be solved by the invention] The purpose of the present invention is to solve the above-mentioned problems of the prior art. An object of the present invention is to provide a sealing member for a scroll compressor or a vacuum pump.

[Means for Solving the Problems] The present invention provides a seal member that is fitted into the end faces of a pair of scroll members disposed so as to mesh with each other in a scroll compressor or a vacuum pump, the seal member having at least the following features: Thermotropic liquid crystal polymer (a) containing one monomer unit represented by the formula 90-5
3 at 350° C. in air, characterized by 0% by weight and a glassy luster on the particle fracture surface.
It is characterized by being formed by a composition comprising 10 to 50% by weight of spherical glass-like carbon (b) whose weight loss when held for 0 minutes is 5% by weight or less.

The details of the present invention will be described below.

The thermotropic liquid crystal polymer referred to in the present invention is a thermoplastic meltable polymer that exhibits optical anisotropy when melted. Such polymers exhibiting optical anisotropy when melted have a property in which polymer molecular chains are regularly arranged in parallel in the melted state.

The nature of the optically anisotropic melt phase can be confirmed by conventional polarization testing using crossed polarizers.

Thermotropic liquid crystal polymers are generally made from monomers that are elongated, flat, and have multiple chain extension bonds in either rigid, coaxial or parallel relationships along the long chains of the molecules.

The thermotropic liquid crystal polymer used in the present invention includes a polymer chain in which part of one polymer chain is composed of polymer segments that form an anisotropic melt phase, and the remaining part is a thermoplastic resin that does not form an anisotropic melt phase. Also included are polymers composed of segments.

Also included are composites of multiple thermotropic liquid crystal polymers.

In the present invention, a polymer or copolymer containing an oxybenzoyl group represented by the above formula as a monomer unit among thermotropic liquid crystal polymers is used. This material has particularly high heat resistance and is preferred as a sliding material.

Among the above (co)polymers, fully aromatic polyesters containing oxybenzoyl groups are more preferred.

The components of the wholly aromatic polyester that forms the optically anisotropic melt phase as described above include (A) at least one of aromatic dicarboxylic acids and alicyclic dicarboxylic acid compounds, and (B) aromatic hydroxycarboxylic acid. At least one acid compound; (C) At least one aromatic diol, alicyclic diol, or aliphatic diol compound; (D) At least one aromatic dithiol, aromatic thiophenol, or aromatic thiol carboxylic acid compound; (E) At least one of aromatic hydroxyamines and aromatic diamine compounds.

These may be composed alone, but in most cases (A)
and (C), (A) and (D), (A) CB) and (C), (
A) (B) and (E), or (A) (B) (C) and (
E) etc.

Examples of the aromatic dicarboxylic acid compound (A1) include terephthalic acid, 4.4'-diphenyldicarphonic acid, 4.
4'-triphenyldicarboxylic acid, 2,6-naphthalene dicarboxylic acid, 1,4-naphthalene dicarboxylic acid, 2,
7-naphthalene dicarboxylic acid, diphenyl ether 4.
4'-dicarboxylic acid, diphenoxyethane-4,4'-dicarboxylic acid, diphenoxybutane-4,4'-dicarboxylic acid, diphenylethane-4,4'-dicarboxylic acid, isophthalic acid, diphenyl ether 3,3'-dicarboxylic acid acids, aromatic dicarboxylic acids such as diphenoxyethane-3,3'-dicarboxylic acid, diphenylethane-3,3'-dicarboxylic acid, 1,6-naphthalene dicarboxylic acid or chloroterephthalic acid, dichloroterephthalic acid, bromoterephthalic acid, Examples include alkyl, alkoxy or halogen substituted products of the above aromatic dicarboxylic acids, such as methyl terephthalic acid, dimethyl terephthalic acid, ethyl terephthalic acid, methoxyterephthalic acid, and ethoxyterephthalic acid.

(A2) As the alicyclic dicarboxylic acid, trans-1,
Alicyclic dicarboxylic acids such as 4-cyclohexanedicarboxylic acid, cis-14-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid or trans-1,4
-(2-methyl)cyclohexanedicarboxylic acid, trans-1,4-(2-chloro)cyclohexanedicarboxylic acid, and alkyl, alkoxy or halogen substituted products of the above alicyclic dicarboxylic acids.

(B) Aromatic hydroxycarboxylic acid compounds include 4-hydroxybenzoic acid, 3-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, and 6-hydroxybenzoic acid.
Aromatic human O-oxycarboxylic acids such as 1-naphthoic acid or 3-methyl-4-hydroxybenzoic acid, 3.5-dimethyl-4-droxybenzoic acid, 2.6-dimethyl-4-
Hydroxybenzoic acid, 3-methoxy-4-hydroxybenzoic acid, 3,5-dimethoxy-4-hydroxybenzoic acid, 6-hydroxy-5-methyl-2-naphthoic acid, 6-
Hydroxy-5-methoxy-2-naphthoic acid, 2-chloro-4-hydroxybenzoic acid, 3-chloro-4-droxybenzoic acid, 2,3-dichloro-4-droxybenzoic acid, 3,5-dicrower 4-hydroxybenzoic acid, 2
．． 5-Dichloro-4-hydroxybenzoic acid, 3-bromo-4-hydroxybenzoic acid, 6-hydroxy-5-chloro-2-naphthoic acid, 6-dichloro-7-chloro-2-naphthoic acid, 6-hydroxy-57- Examples include alkyl, alkoxy or halogen substituted aromatic hydroxycarboxylic acids such as dichloro-2-naphthoic acid.

(C1) Aromatic diols include 4,4'dihydroxydiphenyl, 3,3'-dihydroxydiphenyl, 4
．． 4'-dihydroxytriphenyl, hydroquinone,
Resorcinol, 2,6-naphthalenediol, 4,4'-
Dihydroxydiphenyl ether, bis(4-hydroxyphenoxy)ethane, 3,3'-dihydroxydiphenyl ether, 1,6-naphthalenediol, 2,2-
Bis(4-hydroxyphenyl)propane, bis(4-
Alkyl, alkoxy of aromatic diols such as chlorohydroquinone, methylhydroquinone, t-butylhydroquinone, phenylhydroquinone, methoxyhydroquinone, phenoxyhydroquinone, 4-chlororesorcinol, 4-methylresorcinol, etc. Or a halogen substituted product can be mentioned.

(C2) Alicyclic diols include trans-1,4-cyclohexanediol, cis-1,4-cyclohexanediol, trans-1,4-cyclohexanediol, methanol, cis-1,4-cyclohexane dimetatool, trans-1 ,3cyclohexanediol, cis-1,2-
Alicyclic diols such as cyclohexanediol, trans-1,3-cyclohexane dimetatool or trans-1,4-(2-methyl)cyclohexanediol, trans-1,4-(2-chloro)cyclohexanediol Examples include alkyl, alkoxy or halogen of alicyclic diol.

(C3) Alicyclic diols include ethylene glycol, 1.3-propanediol, 1.4-butanediol,
Examples include linear or branched aliphatic diols such as neopentyl glycol.

(Dl) Aromatic dithiols include benzene 14-dithiol, benzene-1,3-dithiol, 2,6-naphthalene-dithiol, 27-naphthalene-dithiol, etc. 6(D2) aromatic thiophenols include: Examples include 4-mercaptophenol, 3-mercaptophenol, and 6-mercaptophenol.

(D3) Aromatic thiol carboxylic acids include 4-mercaptobenzoic acid, 3-mercaptobenzoic acid, 59 aromatic acid, 6-mercapto-2-naphthoic acid, 7-mercapto-2-naphthoic acid, and the like.

(B) Aromatic droxamine and aromatic diamine compounds include 4-aminophenol, N-methyl-
4-aminephenol, 1,4-phenylenediamine,
N-methyl-1,4-phenylenediamine, N,N'-
Dimethyl-1,4-phenylenediamine, 3-aminophenol, 3-methyl-4-aminophenol, 2-chloro-4-aminophenol, 4-amino-1-naphthol, 4-amino-4'-hydroxydiphenyl, 4-
Amino-4'-hydroxydiphenyl ether, 4-amino-4'-hydroxydiphenylmethane, 4-amino-4'-hydroxydiphenyl sulfide, 4.4'-
Diaminophenyl sulfide (thiodianiline), 4.
4'-diaminodiphenyl sulfone, 2,5-diaminotoluene, 44'-ethylene dianiline, 4,4'-diaminodiphenoxyethane, 4,4'-diaminodiphenylmethane (methylene dianiline), 44' diaminodiphenyl sulfone enyl ether (oxydianiline) and the like.

In addition, the wholly aromatic polyester generally refers to a polyester substantially obtained from an aromatic carboxylic acid and an aromatic alcohol, or the wholly aromatic polyester of the present invention refers to a segment that does not form the above-mentioned anisotropic melt phase. Moieties comprised of esters of aliphatic or cycloaliphatic acids or alcohols are also included. Additionally, in the polyester itself or in segments forming an anisotropic melt phase,
Those consisting of esters with aliphatic or alicyclic acids or alcohols are also included as long as they form an anisotropic melt phase.

Specific examples of wholly aromatic polyester include the following.

Furthermore, the glassy carbon in the present invention basically has a turbostratic structure with extremely small crystal size! It has an I4 structure and has a non-oriented microstructure, and is suitable for thermosetting materials such as phenolic resin, furan resin, epoxy resin, unsaturated polyester resin, urea resin, melamine resin, alkyd resin, and xylene resin. Manufactured by carbonizing resin at high temperatures.

This glass-like carbon is characterized by its fractured surface having a glass-like luster, and is also characterized by the fact that its fractured surface has a glass-like luster.
Diffraction angle (2θ) of spectrum in line diffraction method 23~2
This is also confirmed by the fact that it has a broad peak around 4 degrees. In addition, the X-ray diffraction method follows the usual method and α-rays (
double line).

Conventional carbon materials such as graphite do not have such a broad peak, but have sharp peaks at other diffraction angles (2θ=26.4°) due to crystallinity. The o2 peak is shown.

The glassy carbon of the present invention is preferably one having substantially no peaks characteristic of graphite. In addition, it is possible to simply bake at a low temperature! The carbonized product does not have a glass-like luster on its fractured surface, and of course, in its X-ray diffraction spectrum, it does not have a peak at a specific diffraction angle that is characteristic of not only the glass-like carbon but also graphite.

By the way, since this glassy carbon is produced by carbonizing a thermosetting resin such as a phenol resin as described above, it may contain incompletely carbonized products or uncarbonized products.

In other words, even if the glassy carbon has been confirmed to have a glassy luster on its fracture surface or a broad peak at a specific diffraction angle in the X-ray diffraction spectrum, the glassy carbon is incomplete carbon. It may contain carbonized or uncarbonized substances.

When glassy carbon is blended into a thermoplastic resin, the presence of incompletely carbonized or uncarbonized materials as described above does not pose a problem in the molding process of the thermoplastic resin or in the molded product itself. This is because these incompletely carbonized or uncarbonized products are thought to be the thermosetting resin itself, which is the raw material resin for glassy carbon, or its thermally decomposed low polymer.

On the other hand, one of the characteristics of the thermotropic liquid crystal polymer is that it has a high melting point, which can be said to be unusual among polymers, so its molding temperature is extremely high. In such a case, the two sets of incompletely carbonized or uncarbonized substances contained in the glass-like carbon are likely to decompose and cause the generation of scum. At high temperatures, especially during molding under high pressure such as compression or injection molding, the generation of scum, even in a small amount, can be a fatal defect in the processing process or molded product.

For example, in extreme cases, molding itself may be difficult due to gas generation, or blisters may appear on the surface of the molded product.
If flow marks are observed to occur, the commercial value of the molded product will be lost.

Here, even if the glass-like carbon is characterized by having a glass-like luster on the fractured surface, the type of raw material resin,
Its adjustment method, raw material particle shape, carbonization temperature, carbonization time,
Products with different properties are manufactured depending on the type of atmosphere, the pressure during carbonization, and other conditions. That is, the content of incompletely carbonized OI or uncarbonized substances in the produced glassy carbon and its properties are also different.

In the present invention, considering that it is blended into a thermotropic liquid crystal polymer with a high melting point as mentioned above, it is important to use spherical glass-like carbon whose weight loss is 5% by weight or less under the conditions specific to the liquid crystal polymer. It is.

Here, the weight loss is defined as the weight loss when heating from room temperature to 350° C. at a heating rate of 10° C./minute and holding at that temperature for 30 minutes using, for example, a thermobalance as a measuring device.

Usually, if the carbonization temperature exceeds 800°C, it falls within the range of the above-mentioned weight loss.

When glassy carbon whose weight loss under the above conditions is more than 5% by weight is combined with the thermotropic liquid crystal polymer having a high melting point in the present invention, gas is generated by heating during molding, making molding difficult. It also causes blisters and flow marks on molded products, reducing productivity and product value.

On the other hand, a spherical shape is preferable, and a non-spherical shape such as an amorphous shape, which is more preferably close to a true sphere, is not preferable because it will wear out the metal or resin of the mating material used in the sliding part, for example.

Further, the amount of spherical glass-like carbon added is 10 to 50% by weight, preferably 25 to 40% by weight. Within this range, wear resistance etc. are sufficient and the effects of the present invention can be exhibited.

If the amount of spherical glass-like carbon added is less than 10% by weight, the wear resistance will be insufficient, and if it is added in an amount exceeding 50% by weight, no further improvement in wear resistance can be expected, and the moldability will also deteriorate. Getting worse. Furthermore, the strength of the molded product obtained also decreases.

Here, the inside of the compressor and vacuum pump is caused by friction heat due to the rotation of the scroll or heat generated due to the compression of gas.
Although the temperature rises to around 200° C., this temperature poses no problem for thermotropic liquid crystal polymers that exhibit excellent heat resistance.

In addition, lubricating oil is often used as a lubricant for sliding parts, and although these are inert at room temperature, they can surprisingly become corrosive to contact members at high temperatures due to frictional heat. . In addition, since compressors are also exposed to chemicals such as fluorocarbon gas, resistance to these chemicals is a problem. However, the resin composition made of the thermotropic liquid crystal polymer and spherical glassy carbon in the present invention has sufficient chemical resistance at high temperatures, so it can lubricate even under high temperature atmospheres when lubricating oil is used for sliding parts. oil,
It is not affected by other drugs.

Furthermore, when a thermotropic liquid crystal polymer is melted by applying shearing force, its molecular chains are oriented in the shearing direction and exhibits extremely good fluidity. Injection molding is also fully possible for molded products.

Since it is already in a crystalline state when it melts and flows, there is very little structural change or change in specific volume when it cools and solidifies in the mold, resulting in low molding shrinkage and easy precision molding. .

In addition, because the molecules are highly oriented and form regular molecular chains, the coefficient of linear expansion is small and processing accuracy can be maintained over a wide temperature range.

Here, various additives may be blended into the composition of the present invention6.Additives include inorganic fillers, organic fillers, stabilizers, ultraviolet absorbers, pigments, dyes, modifiers, etc. It can be opened. Among these, inorganic fillers are particularly important and are often used to improve processability, physical properties, etc.

Inorganic fillers include graphite, molybdenum disulfide, bronze, talc, mica, clay, sericite, calcium carbonate, calcium silicate, silica, alumina, aluminum hydroxide, calcium hydroxide, graphite fluoride, potassium titanate, glass. There are fibers, carbon fibers, various whiskers, etc.

Among these, using one or more types of graphite, molybdenum disulfide, glass fiber, and carbon fiber is effective in improving wear resistance.

Furthermore, various thermoplastic and thermosetting resins can be used as organic fillers, and fluororesins such as tetrafluoroethylene resin are particularly effective in improving activity.

For example, when black smoke is blended into the composition of the present invention, 87 to 30% by weight of the thermotropic liquid crystal polymer (a)
, 10 to 50% by weight of the glassy carbon (b) and 3 to 40% by weight of graphite (the sum of a, b and C is 100% by weight).

If the graphite content is less than 3% by weight, the effect of preventing wear of the mating material will not be obtained, while if it exceeds 40% by weight, there will be no further improvement effect and the mechanical strength will decrease.The preferred content of black ship is graphite. (C) 3 to 20% by weight.

When blending a fluororesin into the composition of the present invention, 87 to 40% by weight of the thermotropic liquid crystal polymer (a),
10 to 50% by weight of the glassy carbon (b) and 3 to 20% by weight of the fluororesin (C) (the sum of a, b and C is 1% by weight)
00% by weight) is preferable.

If the amount of fluororesin added is less than 3%, it will not be effective in preventing wear of the mating material, while if it exceeds 20% by weight, there will be no further improvement effect, and the mechanical strength of the molded product will decrease.

Thermotropic liquid crystal polymer and spherical glass-like carbon,
Alternatively, the method of mixing the above additives added to this is:
Various means can be applied without particular limitation.

For example, they may be supplied separately to an extruder and melt-mixed, or they may be premixed in a mixer such as a Henschel mixer or a tumbler, and then supplied to the extruder.

In addition, the glassy carbon particles of the present invention can also be added during polymerization of the thermotropic liquid crystal polymer. Even if a thermotropic liquid crystal polymer composition is blended with glass-like carbon during polymerization, when manufacturing processed products from it, the composition must be processed by injection molding or compression molding. When molding products, thermotropic liquid crystal polymers are melt-molded and exposed to high temperatures. Therefore, even in such a case, the predetermined effects of the present invention can be achieved.

The composition of the present invention thus obtained may be triblended in powder form and molded in the case of force compression molding, which is performed by injection, compression, extrusion, or other methods. .

U Effects of the Invention J The sealing member according to the present invention has the following unique effects. That is, (1) It is strong against friction and wear, and has excellent chemical resistance against fluorocarbon gas and lubricating oil.

(2) It has excellent heat resistance and maintains good sealing performance even under high temperature atmospheres when operating pressure AAI or vacuum pumps.

(3) Since it can be injection molded, it has excellent productivity and has good fluidity, so it can be easily molded.

"Examples" The present invention will be explained in more detail with reference to Examples, but these Examples do not limit the scope of the present invention.
This figure shows a preferred embodiment of the present invention.

First, the raw materials used in the Examples and Comparative Examples are collectively shown.

■ Thermotropic liquid crystal polymers terephthalic acid, 4-droxybenzoic acid, and 4.4
Fully aromatic copolyester consisting of '-dihydroxydiphenyl (trade name: Cyter, manufactured by Amoco Performance Products, Inc., USA).

■ Polyarylene sulfide m fat PP5v! J resin (manufactured by Philips Vetroleum International in the United States: Ryton P-4) ■ Aromatic polyethergetone resin PEEK resin (manufactured by ICI in the United Kingdom: Pictrex PEEK450G> ■ Glassy carbon A to C are commercially available spherical glass It was confirmed that the fractured surfaces of the carbon particles clearly had a glass-like luster, and the X-ray diffraction spectrum measured using α (double line) for Cu- had a diffraction angle (2θ) of 23 ~ around 24 degrees,
Similarly, it had clearly broad peaks, and the sharp peaks characteristic of graphite were not substantially observed.

A: Unipex GCP-50 (H) (Product name) Manufactured by Unitika ■ Weight loss 0.5% by weight B: Bell Pearl C-800 (H) (Product name)
Manufactured by Kanebo ■ Weight loss 1.2% by weight C: Unipex GCP-50 (L) (Product name) Manufactured by Unitika ■ Weight loss 5.1% by weight Reduced Jl: Temperature raised from room temperature to 350℃ at a rate of 10℃/min and the weight loss when held at this temperature for 30 minutes.

(Thermal balance 5SC-5020TG manufactured by Seiko Electronics Industries, Ltd.
/-Measurement was performed using DTA200. ) ■ Graphite manufactured by Nippon Graphite Co., Ltd. ACP (product name) flaky graphite average particle size
10 micrometer ■ Tetrafluoroethylene resin (Daikin Lubron)
L5 (trade name) Particle size: 5 micrometers Examples 1 to 4 The above raw materials were blended in the proportions shown in Table 1, mixed in a Henschel mixer, and then transferred to a twin screw extruder (manufactured by Ikegai Iron Works: PCM- The mixture was melt-kneaded using a 45 type (Model 45) at a temperature of 420°C and a screw rotation speed of 20 OrDI) to form pellets.

Next, this pellet is injection molded (manufactured by Toshiba Machine Co., Ltd.: I
580EPN-3Y type), cylinder temperature 410℃
, injection pressure 1000 krf/c+1, mold temperature 180
A disk with a diameter of 51 mm and a thickness of 3 mm was molded under conditions of .degree. The obtained test piece was subjected to a pressure of 6 kgf using a precious wood type friction and wear tester.
/aa, at a speed of 120 m/min, the outer diameter of the mating material is 26 mm.
The wear coefficient was measured using a ring-shaped 345C steel with an inner diameter of 20 mm.

Furthermore, using the injection molding machine described above, a bending test piece was molded under the same conditions, and the obtained test piece was used to perform ASTM D-
790, the bending strength was measured.

At the same time, the appearance of the 10 test pieces obtained in succession was observed, and the number of test pieces with blisters and flow marks was recorded.

In addition, the same test piece was placed in a 500CC pressure container with Suniso 4
It was put together with 150 ml of G oil and sealed, and 500 g of Freon gas S-3 was injected while cooling. This pressure-resistant container was immersed in silicone oil at 165°C for 48 hours,
After cooling for 4 hours, the gas was removed, the sample was taken out, and dimensional changes in the length direction and weight changes were measured.

Next, the chip seal member shown in Fig. 1 was molded using an injection molding machine (Nestal 5G25 type manufactured by Sumitomo Heavy Industries, Ltd.) at a cylinder temperature of 400°C and an injection pressure of 1500 kif/c.
d, mold temperature 150℃, diameter 0.41m from position 2
Injection molding was performed using a pinpoint gate, and its moldability was examined.

The above results are summarized in Table 1.

The spiral seal member molded above as shown in Fig. 1 is fitted into the end faces of both scroll members of a scroll type compressor whose scroll members are made of aluminum alloy as shown in Figs. 2 and 3 to form a scroll type compressor. After completing the compressor and operating it for 6 months using lubricating oil (product name: Suniso 4G oil) on the sliding parts and using Froncus S-3 as compressed gas, the parts were taken out and their surfaces I checked the condition, but found no particular changes.

In addition, a scroll-type vacuum pump was manufactured by fitting spiral-shaped seal members similar to those shown in FIG. After operating it for 6 months using Suniso 4G oil (trade name), the member was taken out and its surface condition was examined, and no particular changes were observed.

Comparative Examples 1 to 3 The above-mentioned raw materials were blended in the proportions shown in Table 2, and evaluated by pelletizing and molding bending test pieces, discs, and chip seal members in the same manner as in the examples. The results are shown in Table 2.

Comparative Examples 4 to 5 Similar evaluations were conducted using polyarylene sulfide resin and aromatic polyetherketone resin instead of the thermotropic liquid crystal polymer.

However, kneading and injection molding with glass-like carbon using a twin-screw extruder is carried out at 320°C for polyarylene sulfide resin and at 320°C for aromatic polyethergetone resin.
It was carried out at 60°C.

Other conditions are the same. The results are also shown in Table 2.

Comparing Examples 1 to 4 and Comparative Examples 1 to 6, Example 1
~4 is the ratio of the thermotropic liquid crystal polymer to the glassy carbon, and the weight loss of the glassy carbon in air at 350°C for 30 minutes are all within desirable ranges, so the wear coefficient,
Excellent injection moldability.

On the other hand, in Comparative Example 1, the wear coefficient becomes large due to the small amount of glass-like carbon, and in Comparative Example 2, the amount exceeds 50% by weight, resulting in poor injection moldability and product strength.

Furthermore, in Comparative Example 3, glassy carbon was heated at 350°C in air;
If the weight loss in 30 minutes is out of the desired range, this indicates that the injection moldability and appearance of the molded product cannot be satisfied.

Furthermore, in Comparative Examples 4 and 5, conventionally used polyarylene sulfide resin (PPS) and aromatic polyether ketone resin (PEEK) were used instead of thermotropic liquid crystal polymer, but they were inferior in chemical resistance and chip sealing was poor. During injection molding, the entire mold was not completely filled with a short shot, and the desired molded product could not be obtained.

[Brief explanation of drawings]

FIG. 1 is an example of a seal member used in a scroll compressor or vacuum pump according to the present invention. FIG. 2 shows an example in which the seal member according to the present invention is incorporated into a scroll member. FIG. 3 is a sectional view taken along plane A-8 in FIG. 2. 1...Seal member, 2...Gate position during injection molding, 3...Scroll member, 4...Engraving of end drawing (no change in content) Figure 1 Procedure amendment (method) % Formula % Display of one case 1990 Patent Application No. 105274: Name of invention/relationship with the person making the amendment Case Patent applicant name Nippon Petrochemical Co., Ltd.

Claims (3)

[Claims] (1) A sealing member that is fitted into the end faces of a pair of scroll members that are arranged to mesh with each other in a scroll compressor or a vacuum pump, the sealing member being a thermoplastic resin containing at least one unit of a monomer represented by the following formula. A spherical tropic liquid crystal polymer (a) characterized by 90 to 50% by weight and a particle fracture surface having a glassy luster and having a weight loss of 5% by weight or less when held in air at 350°C for 30 minutes. Glassy carbon (b) 10 to 50% by weight (the sum of a and b is 1
1. A sealing member for a scroll compressor or vacuum pump, characterized in that the sealing member is formed of a polymer composition containing 00% by weight) as an essential component. ▲Contains mathematical formulas, chemical formulas, tables, etc.▼ (2) The sealing member for a scroll compressor or vacuum pump according to claim (1), wherein the thermotropic liquid crystal polymer is a wholly aromatic polyester. (3) The sealing member for a scroll compressor or vacuum pump according to claim (1), wherein the glassy carbon is obtained by carbonizing a thermosetting resin.