JP2884363B2 - Seal member in scroll compressor or vacuum pump - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improved seal member in a scroll compressor or a vacuum pump.

[Prior Art] A scroll compressor is arranged such that a pair of scroll members are engaged with each other, and one of the scroll members is fixed and the other does not rotate, but revolves at a constant radius, and is surrounded by both scroll members. The compressed gas is compressed while moving the space to the center. The scroll type vacuum pump has a relative rotation between the fixed and movable scrolls which is opposite to that of the compressor. Usually, the material of these scroll members is
In each case, a metal material such as an aluminum alloy or steel is 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 the two scroll members, and the seal members are fitted into the end surfaces of the two scroll members.

Therefore, the performance required of such a sealing member includes not only the sealing property but also the sliding property such as abrasion resistance, as well as the heat resistance, creep resistance, chemical resistance and the like. In other words, extremely harsh conditions are required as normal sliding conditions.

Here, conventionally, as such a sealing member, a member obtained by adding various fillers to an ethylene tetrafluoride resin has been mainly used. For example, JP-A-63-158362 discloses a method for improving the wear resistance and creep resistance of an ethylene tetrafluoride resin by adding an organic filler and an injection-moldable fluorine resin to the ethylene tetrafluoride resin. It has been disclosed. However, a composition containing a tetrafluoroethylene resin as a main component cannot be injection-molded, so that a desired product is obtained by a method such as punching out a compression-molded flat plate, resulting in poor productivity and, of course, a low product cost. It is undesirably high.

To solve this problem, Japanese Patent Application Laid-Open No. 62-223488 discloses an injection-moldable sealing member containing an aromatic polyetherketone resin, a polyarylene sulfide resin, and a polyetherimide resin as main components. JP-A-63-158362 discloses an injection-moldable seal material mainly composed of an aromatic polyetherketone resin.

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

The spiral seal member of the scroll compressor or the vacuum pump has a small cross-sectional area as shown in FIG.
In addition, since the product length is long, there is a problem that the fluidity of the resin is not sufficient to perform injection molding with the conventional resin, and it is difficult to mold.

 Further, the slidability was insufficient.

[Problems to be Solved by the Invention] An object of the present invention is to solve the above-mentioned problems of the prior art. In particular, it is possible to perform injection molding excellent in heat resistance and Freon gas resistance and to achieve good productivity. An object of the present invention is to provide a seal member in a scroll compressor or a vacuum pump.

[Means for Solving the Problems] The present invention relates to a seal member to be fitted to the end surfaces of a pair of scroll members arranged so as to mesh with each other in a scroll compressor or a vacuum pump, wherein the seal member has at least the following: Thermotropic liquid crystal polymer (a) containing a monomer unit represented by the formula:
10 to 50% by weight of spherical glassy carbon (b) having a weight loss of not more than 5% by weight when held at 350 ° C. for 30 minutes in air, characterized in that the weight% and the particle fracture surface have a glassy gloss % Of the composition.

The details of the present invention are 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 a polymer exhibiting optical anisotropy at the time of melting has a property that polymer molecular chains take a regular parallel arrangement in a molten state. The properties of the optically anisotropic molten phase are
It can be confirmed by a normal polarization inspection method using an orthogonal polarizer.

Thermotropic liquid crystal polymers are generally made from monomers that are elongated, flattened, and have a plurality of chain extension bonds in either a coaxial or parallel relationship that are rigid along the long chain of the molecule.

The thermotropic liquid crystal polymer used in the present invention includes:
A polymer in which a part of one polymer chain is composed of a segment of a polymer forming an anisotropic molten phase and the remaining part is composed of a segment of a thermoplastic resin not forming an anisotropic molten phase is also included. Further, a composite of a plurality of thermotropic liquid crystal polymers is also included.

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

More preferred among the above (co) polymers are wholly aromatic polyesters containing an oxybenzoyl group.

The constituent components of the wholly aromatic polyester forming the optically anisotropic molten phase as described above include (A) at least one kind of aromatic dicarboxylic acid and alicyclic dicarboxylic acid compound, and (B) aromatic hydroxycarboxylic acid. (C) at least one of aromatic diols, alicyclic diols, and aliphatic diol compounds; (D) aromatic dithiols, aromatic thiophenols, and aromatic thiol carboxylic acid compounds; At least one kind, (E) at least one kind of an aromatic hydroxyamine, an aromatic diamine-based compound, and the like. These may be composed independently, but in many cases (A) and (C),
(A) and (D), (A) (B) and (C), (A) (B)
And (E) or (A) (B) (C) and (E).

Examples of the (A1) aromatic dicarboxylic acid compound include terephthalic acid, 4,4'-diphenyldicarboxylic acid, and 4,4'-
Triphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, diphenylether 4,4'-dicarboxylic acid, diphenoxyethane-4,4'dicarboxylic acid, diphenyl Phenoxybutane-4,4'-dicarboxylic acid, diphenylethane-4,4'-dicarboxylic acid, isophthalic acid, diphenylether 3,3'-dicarboxylic acid, diphenoxyethane-
3,3'-dicarboxylic acid, diphenylethane-3,3'-dicarboxylic acid, aromatic dicarboxylic acid such as 1,6-naphthalenedicarboxylic acid or chloroterephthalic acid, dichloroterephthalic acid, bromoterephthalic acid, methylterephthalic acid,
Alkyl, alkoxy or halogen-substituted aromatic dicarboxylic acids such as dimethyl terephthalic acid, ethyl terephthalic acid, methoxy terephthalic acid, ethoxy terephthalic acid and the like.

(A2) As the alicyclic dicarboxylic acid, trans-1,4
An alicyclic dicarboxylic acid such as cyclohexanedicarboxylic acid, cis-1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid or trans-1,4- (2
-Methyl) cyclohexanedicarboxylic acid, trans-1,
Alkyl, alkoxy or halogen-substituted products of the above alicyclic dicarboxylic acids such as 4- (2-chloro) cyclohexanedicarboxylic acid.

(B) Examples of the aromatic hydroxycarboxylic acid-based compound include aromatic hydroxycarboxylic acids such as 4-hydroxybenzoic acid, 3-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, and 6-hydroxy-1-naphthoic acid; 3-methyl-4-hydroxybenzoic acid, 3,5-dimethyl-4-hydroxybenzoic 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-hydroxybenzoic acid, 2,3-dichloro-4-hydroxybenzoic acid,
3,5-dichloro-4-hydroxybenzoic acid, 2,5-dichloro-4-hydroxybenzoic acid, 3-bromo-4-hydroxybenzoic acid, 6-hydroxy-5-chloro-2-naphthoic acid, 6-hydroxy -7-chloro-2-naphthoic acid,
Alkyl, alkoxy or halogen-substituted aromatic hydroxycarboxylic acids such as 6-hydroxy-5,7-dichloro-2-naphthoic acid.

(C1) As aromatic diols, 4,4'-dihydroxydiphenyl, 3,3'-dihydroxydiphenyl, 4,4 '
-Dihydroxytriphenyl, hydroquinone, resorcinol, 2,6-naphthalenediol, 4,4'-dihydroxydiphenylether, bis (4-hydroxyphenoxy) ethane, 3,3'-dihydroxydiphenylether, 1,6-naphthalenediol, Aromatic diols such as 2-bis (4-hydroxyphenyl) propane and bis (4-hydroxyphenyl) methane or chlorohydroquinone, methylhydroquinone, t-butylhydroquinone, phenylhydroquinone, methoxyhydroquinone, phenoxyhydroquinone, 4-chlororesorcinol, Alkyl, alkoxy or halogen-substituted aromatic diols such as 4-methylresorcin.

(C2) As the alicyclic diol, trans-1,4-cyclohexanediol, cis-1,4-cyclohexanediol, trans-1,4-cyclohexanedimethanol, cis-1,4-cyclohexanedimethanol, trans- Alicyclic diols such as 1,3-cyclohexanediol, cis-1,2-cyclohexanediol, trans-1,3-cyclohexanedimethanol or trans-1,2
Alkyl, alkoxy or halogen-substituted alicyclic diols such as 4- (2-methyl) cyclohexanediol and trans-1,4- (2-chloro) cyclohexanediol can be mentioned.

(C3) Examples of the alicyclic diol include linear or branched aliphatic diols such as ethylene glycol, 1,3-propanediol, 1,4-butanediol, and neopentyl glycol.

(D1) As the aromatic dithiol, benzene-1,4-
Examples thereof include dithiol, benzene-1,3-dithiol, 2,6-naphthalene-dithiol, and 2,7-naphthalene-dithiol.

(D2) Examples of the aromatic thiophenol include 4-mercaptophenol, 3-mercaptophenol, and 6-mercaptophenol.

(D3) Examples of the aromatic thiolcarboxylic acid include 4-mercaptobenzoic acid, 3-mercaptobenzoic acid, 6-mercapto-2-naphthoic acid, and 7-mercapto-2-naphthoic acid.

(E) Examples of aromatic hydroxyamine and aromatic diamine-based compounds include 4-aminophenol and N-methyl-4.
-Aminophenol, 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'-hydroxydiphenylsulfide, 4,4'-diaminophenylsulfide (thiodianiline), 4,4'diaminodiphenylsulfone, 2,5-diaminotoluene, 4,4'-ethylenedianiline, 4,4'-diaminodiphenoxyethane, 4,4'-diaminodiphenylmethane (methylenedianiline), 4,4'-diaminodiphenylether (oxydianiline) and the like.

Incidentally, a wholly aromatic polyester generally indicates a polyester substantially obtained from an aromatic carboxylic acid and an aromatic alcohol, but the wholly aromatic polyester of the present invention includes:
The above-mentioned segment portion which does not form the anisotropic molten phase also includes those formed of an ester with an aliphatic or alicyclic acid or alcohol. Further, the polyester itself or the segment forming the anisotropic molten phase also includes those composed of an ester with an aliphatic or alicyclic acid or alcohol as long as they form the anisotropic molten phase. You.

As a specific wholly aromatic polyester, Etc.

Further, the glassy carbon in the present invention has a turbostratic structure having an extremely small crystal size as a basic structure, and has a non-oriented structure as a fine structure, and a phenol resin,
Furan resin, epoxy resin, unsaturated polyester resin,
It is produced by carbonizing a thermosetting resin such as a urea resin, a melamine resin, an alkyd resin, or a xylene resin at a high temperature.

This vitreous carbon is characterized in that its fracture surface has a vitreous luster. In addition, the diffraction angle (2θ) of the spectrum in a normal X-ray diffraction method is 23 to 24.
It is also confirmed by having a broad peak near the degree. In addition, the X-ray diffraction method is measured by Cu-Kα ray (double ray) according to an ordinary method.

A conventional carbon material such as graphite does not have such a wide peak, but shows a sharp _d002 peak due to crystallinity at another diffraction angle (2θ = 26.4 °). As the glassy carbon of the present invention, those having substantially no peak characteristic of graphite are preferred. In addition, the organic carbonized material simply fired at a low temperature does not have a glassy luster in its fracture surface,
Of course, in the X-ray diffraction spectrum, the glassy carbon does not have a specific diffraction angle peak characteristic of graphite, of course.

By the way, this glassy carbon may include an incomplete carbonized product or an uncarbonized product due to being produced by carbonizing a thermosetting resin such as a phenol resin as described above.

That is, even if the fracture surface has been confirmed to have a glassy gloss or to have a broad peak at a specific diffraction angle in the X-ray diffraction spectrum, the glassy carbon is incomplete carbon Or non-carbonized compounds.

When the glassy carbon is blended with the thermoplastic resin, the presence of the incomplete carbonized product or the uncarbonized product as described above may not be a problem in the molding process of the thermoplastic resin or the molded product itself. Many. That is, these incompletely carbonized products or uncarbonized products are considered to be the thermosetting resin itself, which is a raw material resin for glassy carbon, or a thermally decomposed low polymer thereof.

On the other hand, the forming temperature of the thermotropic liquid crystal polymer is extremely high because one of its features is a high melting point which can be said to be abnormal among polymers. In such a case, the above-mentioned incomplete carbonized material or uncarbonized material contained in the glassy carbon is decomposed and easily causes gas generation. At high temperatures, especially in molding under high pressure, such as compression or injection molding, the generation of gas, even in trace amounts, can be a fatal defect in the working process or in the molding. For example, in an extreme case, the molding itself is difficult due to gas generation, or blisters and flow marks are observed on the surface of the molded article, and the commercial value of the molded article is lost.

Here, even if the fracture surface is glassy carbon characterized by having a glassy gloss, the type of raw material resin, its adjustment method, raw material particle shape, carbonization temperature, carbonization time, atmosphere gas type, carbon Products with different properties are produced depending on the pressure at the time of formation and other conditions. That is, the content and properties of the incompletely carbonized or uncarbonized material in the produced glassy carbon are different.

In the present invention, it is important to use a spherical glassy carbon having a weight loss of 5% by weight or less under the conditions specific to the liquid crystal polymer in view of the fact that the compound is mixed with the thermotropic liquid crystal polymer having a high melting point as described above. It is.

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

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

Glassy carbon having a weight loss of more than 5% by weight under the above conditions generates gas due to heating at the time of molding in combination with thermotropic liquid crystal polymer having a high melting point in the present invention, making molding difficult. Or blisters or flow marks on molded products, resulting in reduced productivity and commercial value.

On the other hand, the shape is preferably spherical, and more preferably close to a true sphere. A non-spherical shape such as an irregular shape is not preferable because, for example, a metal or resin of a mating material used for a sliding portion is worn.

The addition amount of spherical glassy carbon is 10 to 50% by weight.
And preferably 25 to 40% by weight. In this range, the abrasion resistance and the like are sufficient, and the effects of the present invention can be exhibited.

If the amount of the spherical glassy carbon is less than 10% by weight, the wear resistance is insufficient. Even if the amount exceeds 50% by weight, no further improvement in the wear resistance can be expected, and the moldability is not improved. Getting worse. Further, the strength of the obtained molded article is also reduced.

Here, the temperature inside the compressor and the vacuum pump rises to around 200 ° C due to frictional heat generated by the rotation of the scroll or heat generated by gas compression, but for a thermotropic liquid crystal polymer exhibiting excellent heat resistance, This temperature is not a problem.

In addition, in many cases, lubricating oil or the like is used as a lubricant in a sliding portion, and these are inactive at normal temperature, but may show unexpectedly corrosiveness to a contact member at a high temperature due to frictional heat. . In addition, since the compressor is exposed to chemicals such as chlorofluorocarbon, resistance to these chemicals is also a problem. However, the resin composition comprising the thermotropic liquid crystal polymer and the spherical glassy carbon in the present invention has sufficient chemical resistance at high temperatures, and therefore can be lubricated even in a high temperature atmosphere when lubricating oil is used for the sliding portion. It is not affected by oils or other drugs.

Further, the thermotropic liquid crystal polymer gives a shearing force at the time of melting, so that the molecular chains are oriented in the shearing direction and exhibit extremely good fluidity. Therefore, as in the sealing member of the present invention, the product has a small cross-sectional area and a long product length. Injection molding is sufficiently possible for molded products.

And since it already shows a crystalline state at the time of melt flow, there is very little change in structure and change in specific volume during cooling and solidification in the mold, and as a result, molding shrinkage is small and precision molding can be easily performed. .

Further, since the molecules are highly oriented and form a rigid molecular chain, the coefficient of linear expansion is small, and the processing accuracy can be maintained over a wide temperature range.

Here, various additives can also be blended in the composition of the present invention.

Additives include inorganic fillers, organic fillers, stabilizers, UV absorbers, pigments, dyes, modifiers, and the like. Of these, inorganic fillers are particularly important, and are often used for improving workability, physical properties, and the like.

As inorganic fillers, graphite, molybdenum disulfide, bronze, talc, mica, clay, sericite, calcium carbonate, calcium silicate, silica, alumina, aluminum hydroxide, calcium hydroxide, graphite fluoride, potassium titanate, glass Fiber, carbon fiber, various whiskers, and the like.

Among them, the use of one or more of graphite, molybdenum disulfide, glass fiber, and carbon fiber is effective in improving wear resistance.

In addition, various thermoplastic and thermosetting resins can be used as the organic filler. In particular, a fluorine-based resin typified by an ethylene tetrafluoride resin is effective in improving the slidability.

For example, when black smoke is added to the composition of the present invention, the thermotropic liquid crystal polymer (a) is used in an amount of 87 to 30% by weight,
10 to 50% by weight of the glassy carbon (b) and 3 to 40% of graphite
% By weight (the sum of a, b and c is 100% by weight).

If the amount of graphite is less than 3% by weight, the effect of preventing the wear of the mating material cannot be obtained, while if it exceeds 40% by weight, there is no further improvement effect and the mechanical strength is lowered. The preferred amount of graphite is 3 to 20% by weight of graphite (c).

When a fluororesin is blended in 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 100% by weight) is preferred.

If the content of the fluororesin is less than 3%, there is no effect of preventing the wear of the mating material, while if it exceeds 20% by weight, there is no further improvement effect. In addition, the mechanical strength of the molded product is reduced.

The method of mixing the thermotropic liquid crystal polymer with the spherical glassy carbon or the additive added thereto is not particularly limited, and various means can be applied.

For example, they may be separately supplied to an extruder and melt-mixed, or may be preliminarily mixed by 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 be added during the polymerization of the thermotropic liquid crystal polymer.
Even in the case of a thermotropic liquid crystal polymer composition in which glassy carbon is blended at the time of polymerization as described above, naturally, when a processed product is produced therefrom, that is, the composition is formed by molding such as injection molding or compression molding. When molding, a thermotropic liquid crystal polymer is melt-molded and exposed to a high temperature. Therefore, even in such a case, the predetermined effect of the present invention is achieved.

The composition of the present invention thus obtained is molded by a method such as injection, compression, or extrusion.In the case of compression molding, each of the compositions may be dry-blended in powder form and molded. .

[Effect of the Invention] The seal member according to the present invention has the following specific effects. That is, (1) it is strong against friction and wear, and
Excellent chemical resistance to lubricating oil.

(2) It has excellent heat resistance even in a high-temperature atmosphere during operation of a compressor or a vacuum pump, so that good sealing properties are maintained.

(3) Since injection molding is possible, it is excellent in productivity, and since it has good fluidity, it can be easily molded.

[Examples] The present invention will be described in more detail with reference to examples. However, these examples do not limit the scope of the present invention, but show preferred embodiments of the present invention.

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

Thermotropic liquid crystal polymer terephthalic acid, 4-hydroxybenzoic acid, and 4,
A wholly aromatic copolyester composed of 4'-dihydroxydiphenyl (trade name: Zyder, manufactured by Amoco Performance Products, USA).

Polyarylene sulfide resin PPS resin (manufactured by Philip Spetroleum International of the United States: Ryton P-4) Aromatic polyetherketone resin PEEK resin (manufactured by ICI UK: Victrex PE)
EK450G) Glassy carbons A to C are commercially available spherical glassy carbons, but it has been confirmed that the fracture surface of each carbon particle has a clear glassy luster, and is measured by Cu-Kα (double line). The X-ray diffraction spectrum also had a clearly broad peak around the diffraction angle (2θ) of 23 to 24 degrees, and a sharp peak unique to graphite was not substantially observed.

A: Univex GCP-50 (H) (trade name), made by Unitika Ltd. Weight loss 0.5% by weight B: Bellpearl C-800 (H) (trade name) Made by Kanebo Ltd., weight loss 1.2% by weight C: Univex GCP -50 (L) (trade name) manufactured by Unitika Ltd. Weight loss 5.1% by weight Weight loss: The temperature is raised from room temperature to 350 ° C. at a rate of 10 ° C./min.
Weight loss when held at this temperature for 30 minutes. (Measured with a thermobalance SSC-5020 TG / DTA200 manufactured by Seiko Denshi Kogyo KK) Graphite ACP (trade name) flaky graphite manufactured by Nippon Graphite Co., Ltd. Average particle size
10 micron meter tetrafluoroethylene resin (Lubron manufactured by Daikin)
L5 (trade name) particle size 5 micrometer Examples 1 to 4 After mixing the above-mentioned raw materials in the ratios shown in Table 1 and mixing them with a Henschel mixer, a twin-screw extruder (PCM- manufactured by Ikeigai Iron Works Co., Ltd.) The mixture was melt-kneaded (temperature: 420 ° C., screw rotation speed: 200 rpm) and granulated into pellets.

Next, the pellets are injected into an injection molding machine (TOSHIBA MACHINE: IS80E
PN-3Y type), cylinder temperature 410 ° C, injection pressure 1000kg
A disk having a diameter of 5 cm and a thickness of 3 mm was formed under the conditions of f / cm ² and a mold temperature of 180 ° C. The obtained test piece was subjected to a wear coefficient test using a Suzuki-type friction and wear tester under the conditions of a pressure of 6 kg f / cm ² and a speed of 120 m / min. It was measured.

Further, using the injection molding machine described above, a bending test piece was molded under the same conditions, and ASTM D-790 was obtained using the obtained test piece.
, The bending strength was measured. At the same time, the appearance of ten continuously obtained test pieces was observed, and the number of blisters and flow marks generated was recorded.

Further, the same test piece was put in a 500 cc pressure-resistant container together with 150 ml of Suniso 4G oil and sealed, and then 500 g of Freon gas S-3 was injected while cooling. 165 ℃
Was immersed in silicone oil for 48 hours, cooled for 4 hours, then gas was released, a sample was taken out, and a dimensional change and a weight change in a length direction were measured.

Next, the tip seal member shown in FIG. 1 was subjected to an injection molding machine (Sumitomo Heavy Industries, Ltd .: Nestal SG25 type) using a cylinder temperature of 400 ° C., an injection pressure of 1500 kg f / cm ² , and a mold temperature of 150 ° C.
Thus, injection molding was performed from the position 2 with a pinpoint gate having a diameter of 0.4 mm, and the moldability was examined.

 The above results are summarized in Table 1.

In addition, the spiral seal member of FIG.
As shown in FIGS. 2 and 3, the scroll member is fitted into both scroll member end faces of the aluminum alloy scroll type compressor to complete the scroll type compressor, and lubricating oil (trade name: SUNISO After operating for 6 months using Freon gas S-3 as a compressed gas while using 4G oil), the member was taken out and its surface condition was examined, but no particular change was observed.

Also, a spiral seal member similar to that shown in FIG. 1 is fitted into both scroll member end surfaces of a scroll vacuum pump in which the scroll is made of an aluminum alloy, thereby producing a scroll vacuum pump. After operating the same for 6 months using a trade name: Suniso 4G oil), the member was taken out and its surface condition was examined, but no particular change was observed.

Comparative Examples 1 to 3 The above raw materials were blended at the ratios shown in Table 2, and pelletized granulation, bending test pieces, disks and chip seal members were formed and evaluated in the same manner as in the examples. The results are shown in Table 2.

Comparative Examples 4 and 5 The same evaluation was performed using a polyarylene sulfide resin and an aromatic polyether ketone resin in place of the thermotropic liquid crystal polymer. However, kneading and injection molding with glassy carbon using a twin screw extruder were performed at 320 ° C. for polyarylene sulfide resin and 360 ° C. for aromatic polyether ketone resin.

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

Here, when Examples 1 to 4 are compared with Comparative Examples 1 to 6, Examples 1 to 4 show that the ratio of the thermotropic liquid crystal polymer to glassy carbon and the weight loss of glassy carbon in air at 350 ° C for 30 minutes are as follows. Since all are within the desired ranges, both the wear coefficient and the injection moldability are excellent.

On the other hand, in Comparative Example 1, the wear coefficient was large due to the small amount of glassy carbon, and in Comparative Example 2, the injection moldability and product strength were poor because it exceeded 50% by weight.

Further, in Comparative Example 3, glassy carbon in air at 350 ° C.
When the weight loss in 0 minutes is out of the desired range, it indicates that the injection moldability and the appearance of the molded product cannot be satisfied.

Further, in Comparative Examples 4 and 5, the conventionally used polyarylene sulfide resin (PPS) and aromatic polyetherketone resin (PEEK) were used instead of the thermotropic liquid crystal polymer. In the case of injection molding, the desired shot was not obtained because the shot was not completely filled in the entire mold due to the short shot.

[Brief description of the drawings]

FIG. 1 is an example of a seal member used in a scroll compressor or a vacuum pump according to the present invention. FIG. 2 shows an example in which the seal member according to the present invention is incorporated in a scroll member. FIG. 3 is a cross-sectional view taken along the plane AB in FIG. 1 ... seal member, 2 ... gate position at the time of injection molding,
3 scroll member 4 end surface

Claims (3)

(57) [Claims] 1. A seal member fitted to end surfaces of a pair of scroll members arranged to engage with each other in a scroll compressor or a vacuum pump, wherein the seal member includes at least a monomer unit represented by the following formula: Thermotropic liquid crystal polymer (a) 90 to 50% by weight and a spherical shape characterized by a particle-breaking surface having a glassy luster and a weight loss of 5% by weight or less when held at 350 ° C. for 30 minutes in air. A scroll-type compressor formed of a polymer composition comprising 10 to 50% by weight of glassy carbon (b) (the sum of a and b is 100% by weight) as an essential component. Or a sealing member in a vacuum pump. formula 2. The seal member in a scroll compressor or a vacuum pump according to claim 1, wherein the thermotropic liquid crystal polymer is a wholly aromatic polyester. 3. The seal member in a scroll compressor or a vacuum pump according to claim 1, wherein the glassy carbon is obtained by carbonizing a thermosetting resin.