JP2766703B2 - Seal part material for scroll compressor - Google Patents

Description

The present invention relates to a seal material for a scroll compressor.

[Conventional technology]

Generally, a scroll-type compressor is provided with a pair of scroll members each having a spiral wall formed on one surface of a substrate, and by engaging the spiral walls of each scroll member with each other in an eccentric state to perform a relative orbital motion. The fluid is compressed while moving the closed space between the winding walls in the center direction, and the fluid is discharged from the central portion. For example, Japanese Patent Application Laid-Open Nos. 50-32512 and 55-81296 disclose the method. It is already well known.

FIG. 1 and FIG. 2 show a conventional scroll member 1 in which a groove 3 is formed at the tip of a spiral wall 2 and a seal material 4 is mounted in the groove 3.
FIG. 3 shows a state in which the scroll member 1 is movable and the fixed scroll member 1 'is eccentrically engaged with each other. 1, 1 'are brought into sliding contact with the bottom of the spiral groove to seal each other.

In the scroll type compressor as described above, the scroll member 1 has recently been made of a light metal such as aluminum or an aluminum alloy in order to reduce its weight, and in order to further reduce the size of the compressor body, The width and depth of the spiral grooves of the scroll members 1, 1 'have also been precisely formed.

Conventionally, a tetrafluoroethylene resin (hereinafter abbreviated as PTFE) has been used as the seal material 4, and this material is heat-resistant, chemical-resistant, flame-retardant, self-lubricating, and non-adhesive. , Has excellent performance such as low friction coefficient,
Creep resistance was not always satisfactory.

Thus, the applicants have disclosed in Japanese Patent Application No. 60-254481 that PTFE and an organic filler (eg, polyphenylene sulfide, polyimide, aromatic polyester, aromatic polyamide, polyamide, polyether ketone, etc.) and injection molding can be used. A material for a seal portion in which a suitable fluororesin powder is added and mixed is disclosed.

However, the seal material made of the above composition has a problem that injection molding is not possible, productivity is poor, and of course, the product cost is high, which is not preferable.

In order to solve the above problem, the applicant has filed Japanese Patent Application No.
Japanese Patent No. -305064 discloses a seal material in which a fluorocarbon polymer, carbon fiber and metal powder are added to an aromatic polyetherketone resin.

However, even with this seal material, the sliding characteristics and mechanical strength under high load are inferior, the mating material is damaged, the abrasion resistance is reduced when sliding for a long time, and the compressor is downsized. However, there is a problem that precise injection molding cannot be dealt with.

[Problems to be solved by the invention]

The object of the present invention is that the conventional sealing member has poor sliding characteristics under high load and poor mechanical strength as described above, easily damages a mating material, and has abrasion resistance and injection moldability during sliding. Improve the inferior point, and have good sliding characteristics even under high load, excellent mechanical strength, abrasion resistance during sliding without damaging the mating material, and a seal material that is easy to perform precise injection molding. It is in.

[Means for solving the problem]

In order to solve the above problems, in the present invention, the polyphenylene sulfide resin is 35 to 80% by weight, the fluorocarbon polymer 10 to 35% by weight, the pitch-based carbon fiber 5 to 5%.
A means is employed in which 15% by weight and 5 to 15% by weight of an organic powder which maintains a solid state at the melt molding temperature of the polyphenylene sulfide resin are added. The details are described below.

First, polyphenylene sulfide resin used in the present invention (hereinafter abbreviated as PPS) is a synthetic resin represented by the general formula Ph-S _n. Where -Ph- is Q is a halogen of F, Cl, Br or CH ₃ , and m is 1
Shows an integer of ~ 4. Of these, the most typical ones are Which is commercially available from Philips Petroleum Corp. under the trademark "Ryton" and is manufactured according to U.S. Pat. No. 3,354,129 (corresponding to Japanese Patent Publication No. 45-3368).
No.). Ryton states that N
It is produced by reacting P-dichlorobenzene with sodium disulfide in a methylpyrrolidone solvent at 160 to 250 ° C. under a pressurized condition, and partially cross-links from those having no cross-links in the resin. Since it is possible to freely produce those having various degrees of polymerization through post-heat treatment steps, it is possible to arbitrarily select and use those having a proper solvent viscosity characteristic for the target solvent blend. In addition, a linear one without a crosslinked structure can be used.

Next, the fluorocarbon polymer in the present invention includes polytetrafluoroethylene, polytetrafluoroethylene / hexafluoropropylene copolymer, polytrichlorofluoroethylene, tetrafluoroethylene / perfluoroalkylvinyl ether copolymer, and the like. PTFE is preferred. Lubricant-grade powder having an average particle size of less than 20 μm is also preferable for PTFE. Examples of commercially available powders include Fluon (trademark) L169, L170, L171, and L171 from ICI, USA, and Lubron from Daikin Industries, Ltd. (Trademark) L-2, L-5, LD-1, Teflon (trademark) TLP-10, TLP-10F-1 of DuPont, USA
And the like.

Further, pitch-based carbon fibers are used as the carbon fibers used in the present invention. This is because the use of pitch-based carbon fibers can reduce the wear of a sliding partner material, and it has been found that the use of PAN-based carbon fibers is inferior in sealing properties and flowability. Further, in order to maintain fluidity during melt molding, the length of the pitch-based carbon fiber is desirably 1 mm or less. It is preferable to use a carbon fiber whose surface is treated with a treating agent such as an epoxy resin, a polyamide resin, a polycarbonate resin, and a polyacetal resin, but the carbon fiber is not limited to these. Examples of such carbon fibers include Kureka M and Kureka C manufactured by Kureha Chemical Industry Co., Ltd.

Further, the organic powder that maintains a solid state at the melt molding temperature of the PPS used in the present invention is selected from aromatic polyesters, aromatic polyamides, polyimides, polyamideimides, polyetheretherketones, heat-infusible granular phenols, and the like. Organic powder comprising a single or a mixture of two or more of them, for example, an organic powder that maintains a solid state at a general PPS melt molding temperature of 300 to 350 ° C.

To mix the PPS, fluorocarbon polymer, pitch-based carbon fiber, and organic powder that maintains a solid state at the melting temperature of the PPS, 35 to 80% by weight of PPS, 10 to 35% by weight of fluorocarbon polymer, 5 to 15% by weight of fiber and 5 to 15% by weight of organic powder. Because the amount of PPS is 3
When the amount is less than 5% by weight, the fluidity of the resin composition is lost, and even if a molded article is obtained by injection molding, its mechanical strength becomes very low and brittle, and the fluorocarbon polymer becomes 10% by weight. If the amount is less than 35% by weight, the lubricating property is insufficient, and if the amount exceeds 35% by weight, the mechanical strength decreases. If the pitch-based carbon fiber is less than 5% by weight, the mechanical strength is insufficient. On the other hand, if it is more than 15% by weight, the soft mating agent is worn away, and good sealing properties cannot be obtained. Also worse. In the case of an organic powder consisting of a single or a mixture of two or more kinds that maintains a solid state at the melt molding temperature of PPS, when the amount is less than 5% by weight,
There is no good flowability at the time of melt molding, and conversely, even at a large amount exceeding 15% by weight, the flowability deteriorates.

Mixing of these various materials can be performed by known means such as dry blending using a Henschel mixer or the like, melt mixing using a brabender, or an extruder.

〔Example〕

The raw materials used for the resin and the comparative examples are collectively shown as follows. That is, PPS (manufactured by Phillips Petroleum Corporation, USA: Ryton P-4) fluorocarbon polymer (manufactured by Daikin Industries, Ltd .: Lubron L-5) [referred to as PTFE] Pitch-based carbon fiber (manufactured by Kureha Chemical Company: Kureha M207S fiber length) PAN-based carbon fiber (Toho Rayon Co., Ltd .: Vesfight HTA)
-C6-E, fiber length 7 to 8 µm) Oxybenzoyl polyester (Sumitomo Chemical Co., Ltd .: Econol E101M) Molybdenum disulfide (Dow Corning Co., Ltd .: Molycoat Z) Polyethylene (Mitsui Petrochemical Co., Ltd .: Hi-Zex Million 240S) Polyimide ( Ube Industries, Ltd .: Polyimide powder R type Polyetheretherketone (ICI, UK: Udel-PEEK 150P) [PEEK] Polyamide (Amoco, USA: TORON4000 [PAI] Polyetherimide (General Electric, USA) Company: ULTEM1000 [PEI] Examples 1 to 9 The above various raw materials are blended in the proportions shown in Table 1,
After thoroughly mixing with a Henschel mixer, the mixture is fed to a twin-screw extruder (PCM-30, manufactured by Ikegi Tekko Co., Ltd.), and is extruded from a strand die having a temperature of 320 ° C., a screw rotation speed of 50 rpm, and 7 holes of 2 mm in diameter and pellets. And granulated. The pellets are heated at a barrel temperature of 300 to 330 ° C, a mold temperature of 140 ° C, and an injection pressure of 1000 kg / cm.
^A predetermined test piece was produced by using an injection molding machine of No. ^{2 and} the bending strength kg / cm ² of the obtained test piece was based on ASTM-D790 and the Izod impact strength kg / cm / cm was based on ASTM-D256, and the coefficient of friction was Is 17mm inside diameter using Suzuki / Matsubara friction and wear tester,
The value under the conditions of an outer diameter of 21 mm, a ring specimen having a length of 10 mm, a pressure of 10 kg / cm ² , and a speed of 10 m per minute is further increased to a limit PV value kg / cm ²
・ The m / min was set at a constant speed V of 308 m / min using the Suzuki-Matsubara friction wear tester and a ring specimen of the same size, and the pressure P was adjusted to 5000, 6000, and 7000 in Suniso 4GS oil.
…… When the specimen starts to undergo abnormal wear accompanied by melting or the coefficient of friction becomes suddenly unstable while increasing in increments of 1000 kg / cm ² · m / min in 5 minutes. PV
Values and the actual heat resistance are shown in FIG.
(The expansion curve of a circle with a radius of 2 mm is 1.5 m in width, 1.5 mm in thickness, and deployment length is 300 mm). ,
During the test under the conditions of the operation time of 10 hours, the evaluation was made based on the time when the seal portion material 4 caused abnormal wear accompanied by melting or the wear coefficient became rapidly unstable.

Next, in the above-mentioned heat resistance test of the actual machine, the degree of damage of the mating material was determined by the mating sliding portion (made of aluminum) after an operation time of 10 hours.
When the damage depth was 0 to 5 μm, it was evaluated as ◎, when 5 to 10 μm, 10, when 10 to 15 μm, Δ, and when more than 15 μm, ×. Injection moldability was determined by creating an injection mold having a width of 1.5 mm, a thickness of 1.5 mm and a development length of 400 mm in the shape of the seal part material (expansion curve of a circle with a radius of mm) shown in FIG. The resin injection port (gate port) is provided at the outer end, the barrel temperature is 300-330 ° C, the mold temperature is 140 ° C, and the injection pressure is 1
When shaped under injection conditions of 000 kg / cm ² , the cross mark indicates that the flowable length of the resin is 200 to 250 mm, and the cross mark indicates that the length is 250 to 300 mm.
When 0 to 350 mm, it was evaluated as a circle, and when it was 350 to 400 mm, it was evaluated as a double circle. Table 2 summarizes the obtained measured values.

Comparative Examples 1 to 12: Except that the above-mentioned raw materials were blended in the proportions shown in Table 3, the same operation as in Examples 1 to 9 was carried out to prepare test pieces, and their bending strength, Izod impact strength, and coefficient of friction were prepared. ,
The critical PV value, the durability of the actual machine, the degree of damage to the partner material, and the injection moldability were measured. The results obtained are summarized in Table 4.

In Table 4, those indicated by "-" in the column of the actual machine durability and the column of the damage degree of the mating member mean that the test was impossible because the moldability was poor and a required chip seal was not obtained.

Here, comparing Examples 1 to 9 and Comparative Examples 1 to 12,
Since the compounding ratios of Examples 1 to 9 are all within the range considered to be desirable, mechanical properties, lubricating properties, and critical PV
It is excellent in all aspects such as value, actual machine durability test, damage degree of mating material, and injection moldability.

However, for relatively 1 to 12, the mixing ratio of PPS, fluorocarbon polymer, pitch-based carbon fiber, and organic powder is deviated from the desired range, and if the carbon fiber is PAN-based, or PPS is melted. An organic powder or inorganic substance that does not maintain a solid state at a temperature cannot satisfy all the characteristics described in the examples. For example, in Comparative Examples 1 and 2, when the organic powder exceeds 15% by weight or less than 5% by weight, the injection moldability is poor. In the case of Comparative Example 3, the coefficient of friction was poor because PTFE was less than 10% by weight, and in Comparative Examples 4 and 5, the mechanical strength and the critical PV value were low because the compounding ratio of the carbon fibers was outside the desired range. In Comparative Examples 7 and 8, the injection moldability was very poor because no organic powder was blended. In Comparative Examples 6 and 9, the carbon fibers
In addition to being a PAN type, the compounding ratio of the organic powder was 15% by weight, and the mating material had a poor degree of damage or was extremely poor in flowability. Furthermore, Comparative Examples 10 and 11 were obtained by adding molybdenum disulfide as an inorganic substance and polyethylene which did not maintain a solid state at the melt molding temperature of PPS, and had poor flowability. Therefore, it was necessary to keep the organic powder in a solid state at the melting temperature of PPS, and it became clear that oxybenzoyl polyester was preferred. In Comparative Example 12, polyimide was used as the organic powder, but the mixing ratio exceeded 15% by weight, so that the flowability was poor as in Comparative Example 9.

Comparative Examples 13 to 15: Specimens were prepared by exactly the same operations as in Examples 1 to 9 except that the above-mentioned raw materials were blended in the proportions shown in Table 5, and the injection moldability was examined. The results were evaluated in exactly the same manner as in Comparative Examples 1 to 3, and are also shown in Table 5.

As is clear from the measurement results in Table 5, the main raw material is PP
For resins other than S, no improvement was observed in injection moldability even when the other components and their proportions were appropriate.

〔effect〕

As is clear from the above, the seal material of the present invention is excellent in sliding characteristics under high load, mechanical strength, damage degree of a mating material, etc., and is precise with the downsizing of the scroll compressor. It is a material with good flowability that enables injection molding, and will greatly contribute to the specifications of future scroll compressors. Therefore, it can be said that the significance of the present invention is extremely large.

[Brief description of the drawings]

1 is a perspective view of a scroll member, FIG. 2 is a cross-sectional view of a main part of FIG. 1, and FIG. 3 is a cross-sectional view illustrating an internal structure of a compressor in which a scroll member is engaged. 1, 1 '... scroll member, 2 ... spiral wall, 3 ...
Groove, 4 ... Seal material.

Claims (1)

(57) [Claims] 1. A polyphenylene sulfide resin of 35 to 80% by weight, a fluorocarbon polymer of 10 to 35% by weight, a pitch-based carbon fiber of 5 to 15% by weight, and an organic powder 5 which is solid at the melt molding temperature of the polyphenylene sulfide resin.
A scroll material for a scroll type compressor, characterized by adding up to 15% by weight.