JPS599580B2 - Highly lubricating resin composition - Google Patents

Description

Detailed Description of the Invention The present invention provides a novel resin composition with high lubricity, more specifically, a thermoplastic resin and an inorganic filler bonded in advance using a radically reactive monomer or polymer. The present invention relates to a resin composition with excellent frictional properties, which is obtained by adding an oil retaining agent and an oil retaining agent.

Until now, by adding oil to thermoplastic resin,
Many attempts have been made to improve the frictional properties and to create highly lubricating resin compositions that can be used for long periods without lubrication.

For example, a method in which a lubricating oil is directly incorporated into a polyacetal resin or a polyamide resin (Japanese Patent Publication No. 46-5321), a composition in which an ester lubricating oil is added to a polycarbonate resin (Japanese Patent Publication No. 47-41092), A composition that is supported or retained on a substance and added to a resin (
JP-A-48-22133, JP-A-49-9974
0, Japanese Unexamined Patent Publication No. 49-104941, etc.) have been proposed. However, although these compositions are quite effective in providing lubricity,
Other properties such as mechanical strength are not yet fully satisfactory. The present inventors added an inorganic filler to increase the surface hardness of highly lubricating resins, as they are often used in sliding parts such as bearings, making them hard, strong, and with excellent frictional properties. When we investigated the possibility of obtaining a resin composition with a similar structure, we found that if a thermoplastic resin that had been combined with an inorganic filler using a radically reactive monomer or polymer was used as the basic thermoplastic resin, it would be possible to simply add the inorganic filler. The present inventors have discovered the surprising fact that the friction coefficient (μ) is lower at the same time as the strength is equal to or higher than that in the conventional case, and has led to the present invention.

In general, creating some kind of chemical bond at the interface between an inorganic filler and a thermoplastic resin has the advantage of increasing strength compared to simply adding an inorganic filler; There was usually almost no change in μ). Therefore, it can be said that one feature of the composition of the present invention is an extremely unique phenomenon.

That is, the present invention provides (4) a base thermoplastic resin reinforced by bonding an inorganic filler with a radically reactive monomer or polymer. ,(
b glaze 0.1-25 weight? , (c) oil retention agent 0.1-25
% by weight, and the ratio of oil weight/oil retention agent weight is 0.3~
25 is provided. The inorganic filler used in the present invention may be of any type and is not particularly limited.

Further, the shape thereof is also arbitrary, and may be any shape such as powder, flake, needle, or fiber. Examples of inorganic fillers preferably used in the present invention include glass fiber, glass beads, carbon fiber, asbestos, alumina fiber, titanium phosphate fiber, magnesium oxide, silica, kaolin, mica, aluminum oxide,
Magnesium carbonate, calcium carbonate, barium carbonate, magnesium hydroxide, aluminum hydroxide, calcium sulfate, barium sulfate, carbon black, titanium oxide, iron oxide, zinc oxide, lead oxide, cadmium oxide, graphite, molybdenum disulfide, fluoride Examples include graphite, boron nitride, gold powder, silver powder, copper powder, aluminum powder, iron powder, etc. The base thermoplastic resin used in the present invention is a thermoplastic resin that can be combined with an inorganic filler by a radically reactive monomer or polymer, and is soluble in the oil used at room temperature. It does not swell more than ζ, and does not absorb more oil than the weight of oil absorbed by the oil retention agent under the same conditions at the molding temperature. In more detail, this base thermoplastic resin has a thickness of about 1
m! ．． When a piece of resin weighing about 19 mm is immersed in oil at room temperature for 5 days, it is preferable that the piece of resin does not dissolve in oil and does not swell after absorbing 3% by weight or more of oil. When the test piece is immersed in oil for 5 hours at the molding temperature of the base thermoplastic resin, the resin piece does not dissolve in the oil and is preferably 1/2 or more of the amount of oil absorbed by the oil retention agent measured under the same conditions.
Z or more, more preferably K. It is best to choose one that does not absorb more oil. Examples of the base thermoplastic resin preferably used in the present invention include polyacetal resin, polyamide resin, polyester resin, polycarbonate resin, polyvinyl chloride resin, polystyrene resin, acrylic resin, polyvinyl alcohol resin, cellulose resin, Examples include base resin, polyphenylene oxide resin, polyphenylene sulfide resin, polysulfone resin, polyallyl ether resin, polyallyl sulfone resin, polyether sulfone resin, and polyvinyl acetal resin.

Examples of radically reactive monomers or polymers used in the present invention include unsaturated fatty acids such as acrylic acid and methacrylic acid and their esters, derivatives such as amides, styrene, divinylbenzene, diacrylic phthalate, and vinyl acetate. Monomers or low molecular weight polymers having ethylenically unsaturated bonds such as fatty acid vinyl esters, vinyl pyridine, synchropentadiene, 1,4-hexadiene, butadiene oligomers, unsaturated polyesters, isocyanate compounds, epoxy compounds, etc. It is preferable to select one or more types appropriately depending on the inorganic filler and base thermoplastic resin used.

The oil used in the present invention is liquid at room temperature, or
Alternatively, it is an oil having a lubricating effect that becomes liquid at a temperature below the molding temperature of the base thermoplastic resin even if it is solid at room temperature, and includes any commonly used lubricating oil. Examples of oils preferably used in the present invention include paraffinic, naphthenic, and aromatic hydrocarbon oils, alkyl monoesters, alkyl diesters,
Examples include ester oils such as phosphoric acid esters. The oil retention agent used in the present invention is a thermoplastic resin that does not dissolve in oil at room temperature, but dissolves in oil at the molding temperature of the base thermoplastic resin, or has a ratio of oil weight/oil retention agent weight. It absorbs oil of 0.3 or more and swells.
In more detail about this oil retainer, it has a thickness of approximately 11L.
71. When a resin piece weighing approximately 19 mm was immersed in oil for 5 hours at room temperature, the resin piece did not dissolve in the oil, and a similar test piece was immersed in oil for 5 days at the molding temperature of the base thermoplastic resin. In this case, the resin pieces either dissolve in oil or absorb oil and swell at a ratio of oil weight/oil retention agent weight of 0.3 or more. Examples of oil retention agents preferably used in the present invention include polyolefins, polystyrene, polyvinyl chloride, etc. Examples of polyolefins include polyethylene, polypropylene, ethylene monovinyl acetate copolymers, and the like. In the present invention, it is necessary to bond the inorganic filler and the base thermoplastic resin in advance using a radically reactive monomer or polymer.

The effects of the present invention are extremely uniquely exhibited by the combination of the inorganic filler and the base thermoplastic resin. Even if an attempt is made to bind the agents, sufficient binding cannot be achieved due to the influence of the oil, making it impossible to achieve the effects of the present invention satisfactorily. The blending ratio of the inorganic filler and the base thermoplastic resin is not particularly limited, but a commonly used blending ratio of about 5 to 150 parts by weight of the inorganic filler to 100 parts by weight of the base thermoplastic resin is preferred. Further, the amount of the radically reactive monomer or polymer is not particularly limited as long as it can bond the base thermoplastic resin and the inorganic filler. Preferably it is 0.01 to 30% by weight based on the inorganic filler. There are no particular restrictions on the method of bonding using radically reactive monomers or polymers, and general methods such as adding a radical polymerization initiator and heating may be used, or special methods specific to the resin may be used. It can also be used. Furthermore, if necessary, it is also possible to use a blend of two or more types of thermoplastic resins as the base thermoplastic resin, and two or more types of inorganic fillers may be used in combination. In the present invention, the combination of the base thermoplastic resin reinforced with the above-mentioned inorganic filler, oil, and oil retention agent is also extremely important.

In other words, since the base thermoplastic resin and oil retention agent are determined by the degree of affinity with oil, the type of base thermoplastic resin and oil retention agent that can be effectively used depends on the type of oil. is somewhat different. In the present invention, the blending amounts of the base thermoplastic resin reinforced with an inorganic filler, oil, and oil retention agent are also important.

The total amount of inorganic filler and base thermoplastic resin is 99.
The amount is 8 to 50% by weight, and if it exceeds 99.8% by weight, the effect of adding the oil and oil retaining agent will not be sufficiently exhibited, and if it is less than 50% by weight, the original properties of the base thermoplastic resin will be impaired. Preferably it is 98.5 to 70% by weight, more preferably 96 to 80% by weight. It is. The amount of oil is 0
．． 1 to 25% by weight, and 0.1% by weight? If it is less than 25% by weight, the lubricity will be poor, and if it exceeds 25% by weight, the properties of the base resin will be impaired.

Preferably 1 to 20 weight? and particularly preferably from 3 to
It is 15% by weight. Is the amount of oil retention agent 0.1 to 25% by weight? And 0.1 weight? If it is less than 25% by weight, the effect as an oil retaining agent will not be sufficiently exhibited, and if it exceeds 25% by weight, the properties of the base resin will be impaired.

Preferably it is 0.5 to 10% by weight, more preferably 1 to 5% by weight. The value of oil weight/oil retention agent weight is 0
．． 3 to 25, and if this value is less than 0.3, the lubricity will be poor, and if it exceeds 25, the effect of adding the oil retaining agent will be diminished. Preferably 2 to 15, more preferably 3 to 15
It is 12. The composition of the present invention may further contain various additives, such as stabilizers, solid lubricants, colorants, antistatic agents, ultraviolet absorbers, flame retardants, etc., as necessary.

The composition of the present invention can be obtained by heating and mixing the base thermoplastic resin reinforced with an inorganic filler, oil, and oil retaining agent. Just choose appropriately.

Further, a base thermoplastic resin may be further added during mixing. Examples are shown below to further clarify the present invention, but the present invention is not limited to the following examples. Example 1 Polyacetal resin (homopolymer, M-13) 5,0
009 carbon fiber (HT type, chopped fiber length 3mw!) 1,2509 and unsaturated polyester (
A polyester consisting of phthalic anhydride, maleic anhydride, and propylene glycol, with an average degree of polymerization of about 25) 759, was lightly premixed in a tumbler, kneaded in a single-screw vent type extruder set at 200°C, and pelletized.

4450 g of the pellets thus obtained, 450 g of naphthenic oil (SUS56, 98.35C), and 1009 high density polyethylene (MI=0.04) were mixed while heating to about 130° C. using a pen shell mixer.

This was extruded into pellets using a single-screw vent extruder and molded into cylindrical test pieces using a single-screw injection molding machine. The friction coefficient of this test piece was measured using a thrust type friction and wear tester (Suzuki type) (load: 2 kg/Cd, linear velocity: 1.
2c! n/Sec. Mating material S45C) However, μ is 0.
It was 06. When the same experiment was conducted using polyacetal resin to which carbon fibers were simply added, μ was 0.
It was 12. Example 2 A test piece was prepared using Diuracon GC25 (manufactured by Polyplastics K.K., registered trade name of glass fiber reinforced polyacetal resin copolymer) 47009, dioctyl sebacate 2509, and high density polyethylene (MIl) 509 in the same manner as in Example 1. It was molded into.

When the friction coefficient was measured under the same conditions, μ was 0.11. When the same experiment was conducted using a polyacetal resin to which glass fibers were simply added, μ was 0.20. Example 3 Glass fiber (chopped strand, fiber length 61u) 2
,0009 and acrylic acid 50f! were mixed lightly in a tumbler, and this was charged into a single-screw vent type extruder set at 230°C together with 4,0009 polyamide resin (nylon 6, sulfuric acid viscosity = 2.7), kneaded, and pelletized. .

Pellet 4,0009 thus obtained and Example 1
The naphthenic oil 7509 used in
)2509 in a pen shell mixer and heat to about 130℃.
Mix while heating.

This was again kneaded and pelletized using a single-screw vent type extruder set at 230°C, and then molded into a cylindrical test piece using a single-screw injection molding machine. When the friction coefficient was measured under the same conditions, μ was 0.14.

When the same experiment was conducted using a polyamide resin to which glass fibers were simply added, μ was 0.22. Example 4 γ-glycidoxypropionic acid 809, heavy calcium carbonate 2,0009 and polyamide resin (nylon 66,
Sulfuric acid viscosity = 2.5) After lightly mixing 3,0009 with a tumbler, kneading with a single-screw vent type extruder set at 290 ° C.
Made into pellets.

The composition 4,3009 and paraffinic oil (10 cst at 37.8°C) 6009 and high density polyethylene (MI=5
) were mixed using a pen shell mixer while heating to about 130°C. This was again kneaded and pelletized using a single-screw vent type extruder set at 290°C, and molded into a cylindrical test piece using a single-screw injection molding machine. When the friction coefficient was measured under the same conditions, μ was 0.08.

When the same experiment was conducted using a polyamide resin to which calcium carbonate was simply added, μ was 0.12. Example 5 Glass fiber (chopped strand, fiber length 6m1L)
2,4009,2-methyl-5-vinylpyridine 120
An experiment similar to Example 1 was conducted using 5,6009 g and polyester resin (polybutylene terephthalate, solution viscosity = 1.2).

However, the set temperature of the extruder was 250°C both times. The friction coefficient μ of the obtained test piece was 0.09. When the same experiment was conducted using a polyester resin to which glass fibers were simply added, μ was 0.16. Example 6 In Example 5, clay was used instead of glass fiber.

Claims (1)

[Claims] 1 (a) 99.8-50% by weight of a base thermoplastic resin reinforced by bonding an inorganic filler with a radically reactive monomer or polymer, (b) 0.1-2% oil
A highly lubricating resin composition comprising 5% by weight and (c) 0.1 to 25% by weight of an oil retention agent, and having an oil weight/oil retention agent weight ratio of 0.3 to 25.