JPH09157520A - Polyamide resin composition and sliding member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polyamide resin compsn. which hardly forms mold deposit during molding and is excellent in mechanical properties and abrasion resistance and provide a sliding member produced therefrom. SOLUTION: This resin compsn. is prepd. by incorporating 0.001-5 pts.wt. phosphorous ester, phosphoric ester, or phenol stabilizer or 0.001-5 pts.wt. sulfur thermal stabilizer into 100 pts.wt. resin mixture which comprises 90-50wt.% melt-moldable polymide resin (A) and 10-50wt.% masterbatch (B) obtd. by kneading 10-99wt.% modified polyolefin resin and 90-1wt.% resin component comprising resin A and/or a polyamide resin having an m.p. lower than that of resin A.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to molded article materials, particularly oilless bearings for OA equipment, automobiles, VTR parts, etc.
The present invention relates to a member such as a gear that is required to have abrasion resistance and a resin composition suitable for the member. More specifically, the present invention provides improved mold deposit during molding,
The generation of decomposition gas during molding is significantly suppressed,
The present invention also relates to a thermoplastic resin composition having excellent mechanical properties and friction and wear properties, and a sliding member obtained from the same.

[0002]

2. Description of the Related Art Conventionally, a resin excellent in friction and wear characteristics has a structure with little branching in terms of molecular structure, that is, a resin such as polyethylene, polytetrafluoroethylene, or polyacetal, or a heat-resistant resin depending on the purpose of use, that is, Aromatic nylon and polyphenylene sulfide,
Polyetheretherketone, polyamideimide, etc. have been used.

In recent years, the technology of polymer alloys has advanced,
Friction and wear characteristics have been improved by adding various polymers and low molecular weight compounds such as oil and metal soap. However, a polymer having good friction and wear characteristics exhibits excellent friction and wear behavior by itself, but it is OA.
Use of precision parts such as equipment is restricted due to dimensional accuracy and rigidity problems.

Polyacetal and polyethylene are widely used as gears in various precision instruments such as VTR as materials having excellent friction and wear characteristics.
At present, the use of parts is restricted for components that have low heat resistance and that require high-precision dimensions due to dimensional precision problems. On the other hand, in the improvement of friction and wear characteristics by adding oil, low molecular weight compound and the like, there are problems such as bleeding out on the surface of the molded product due to molding at high temperature during injection molding and deterioration of physical properties due to addition.

Recently, with the technology of polymer alloy,
Polyethylene or polytetrafluoroethylene is added for the purpose of further improving the friction and wear characteristics without deteriorating the physical properties of the base polymer having excellent friction and wear characteristics for these friction and wear resistant materials, and further oil and various inorganic fillers,
In some cases, a friction and wear resistant material containing a compatibilizer has been developed for the purpose of improving the interfacial strength between different resins.

However, the resins and oils added for the purpose of improving these friction and wear characteristics serve as a base.
In the temperature range of blending with so-called engineering plastic and injection molding, there is a problem that heat resistance is poor and gas is generated due to decomposition of the polymer and additives contained in the polymer to cause mold deposit.

[0007]

SUMMARY OF THE INVENTION In view of the above problems, the present invention is directed to obtaining a composition which is excellent in dimensional stability and resistance to friction and wear, and in which sliding characteristics in which mold deposit does not occur during molding are excellent.

[0008]

A masterbatch is prepared in advance using a modified polyolefin and a base polyamide resin and / or a polyamide resin having a melting point lower than that, and this is added to the base polyamide resin as a friction and wear property improving agent. By doing so, it was found that it is possible to remarkably suppress the generation of mold deposit while having the frictional wear characteristics higher than those of the conventional ones, and the present invention has been completed.

That is, the present invention provides (A) 90-50% by weight of melt-processable polyamide resin.
And (B) 10 to 99% by weight of modified polyolefin resin and 10 to 50% by weight of masterbatch resin obtained by kneading (A) polyamide resin and / or 1 to 90% by weight of polyamide resin having a melting point lower than that (A). Consists of
And

The (C) phosphite ester, phosphoric acid ester, phenol-based stabilizer or sulfur-based heat stabilizer is added in an amount of 0.001 per 100 parts by weight of the total amount of the above components (A) and (B).
A polyamide resin composition containing 5 to 5 parts by weight and a sliding member obtained by molding the same. In the present invention, the sliding member means a member that slides with another member such as a guide roll such as a tape or a gear.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the components constituting the composition of the present invention will be described in detail. The (A) polyamide resin used in the present invention is not particularly limited as long as it can be melt-processed, and commercially available products can be used.
Preferably, one having a high molecular weight is used in order to improve the friction and wear resistance. Further, in general, the melting point is 200
A polyamide having a temperature of ℃ or more is preferable, and taking the compatibility with the modified polyolefin, the processing temperature, etc. into consideration, the polyamide is preferably a crystalline polyamide such as polyamide 66, polyamide 6, semi-aromatic polyamide, or polyamide 46. Polyamide which is not subjected to a treatment such as acetylation and has a polar group such as an amino group and a carboxyl group is preferable.

The masterbatch of the modified polyolefin resin (B) used in the present invention of 10 to 99% by weight and the base polyamide resin of (A) and / or the polyamide resin having a melting point lower than that of 1 to 90% by weight means It is a component that is a feature of the present invention, and it suppresses the generation of mold deposit of thermoplastic resin and has an action as a friction and wear property improver.

The polyamide resin used in the preparation of the masterbatch may be the same as the base (A) polyamide resin, but in view of moldability, it has a lower melting point than that of the (A) base polyamide resin. It is preferable to use a polyamide having a low melting point of preferably 5 ° C or higher, more preferably 10 ° C or higher, and particularly preferably 20 ° C or higher. For example, if the (A) base polyamide is polyamide 66, polyamide 11 or polyamide 1
A soft polyamide such as 2 is preferred.

The polyamide used for preparing the masterbatch of the present invention may be an amorphous polyamide whose melting point is not observable. The modified polyolefin used in the present invention is a polyolefin such as low-density polyethylene, high-density polyethylene, polypropylene, ethylene / propylene block copolymer, or ethylene / butene-1 copolymer containing maleic anhydride, acrylic acid or glycidyl group. It is used after being modified with a modifier having a polar group or a reactive functional group such as a compound, a diene compound and an alkoxysilane.

The modification with a modifying agent can be obtained by copolymerizing an olefin and a modifying agent, in addition to the method of adding or grafting the modifying agent to the polyolefin. Among them, polyolefin modified with maleic anhydride, or
A modified polyethylene (made by Mitsubishi Kagaku Co., Ltd .: trade name: Linklon), which is easy to form a gel and has a highly reactive vinyltrimethoxysilane grafted or copolymerized, is preferable. In particular, it is possible to change the gel fraction of the active silane-modified polyethylene by changing the masterbatch preparation conditions according to the required performance of friction and wear characteristics. Further, these modified polyolefins may be used in combination with a maleic anhydride-modified or diene-containing modified polyolefin in combination with an active silane-modified polyolefin for the purpose of further improving the compatibility.

In the present invention, the mechanism by which the masterbatch contributes to the suppression of deposit generation and the improvement of abrasion resistance is not necessarily clear, but the modified site of the modified polyolefin reacts with a low molecular weight product generated at the polymer end or due to hydrolysis or the like. However, by preventing the generation of decomposition gas, or by adding modified polyolefin, gels due to intramolecular and / or intermolecular cross-linking may be generated, and the deposit generated by the gas generated during normal polyolefin decomposition may be suppressed. Inferred.

As the heat stabilizer (C) such as phosphite ester and phosphoric acid ester used in the present invention, a commercially available heat stabilizer can be used. Further, a phenol-based or sulfur-based heat stabilizer may be used. It is preferable that the decomposition temperature and the sublimation temperature are as high as possible in consideration of the molding processing temperature, but it is not particularly limited. Specifically, phosphite and phosphate are OH
An ester of phosphorous acid or phosphoric acid with a compound having an alkyl, alkylene, aryl, alkaryl, aryl, or alicyclic compound having a group can be used.

In particular, triphenyl phosphite, tetrakis (2,4-di-t-butyl-4-methylphenyl)
Pentaerythritol-diphosphite is preferred. As the phenol-based stabilizer, a compound having a hindered phenol structure is used, and specifically, triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6
-Hexanediol-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate],
2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-t-butylanilino) -1,3
5-triazine, pentaerythrityl-tetrakis [3
-(3,5-di-t-butyl-4-hydroxyphenyl) propionate], 2,2-thio-diethylenebis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], Octadecyl-3- (3,5
-Di-t-butyl-4-hydroxyphenyl) propionate, 2,2-thiobis (4-methyl-6-t-butylphenol), N, N'-hexamethylenebis (3,3
5-di-t-butyl-4-hydroxy-hydrocinnamide), 3,5-di-t-butyl-4-hydroxy-benzylphosphonate-diethyl ester, 1,3,3.
5-trimethyl-2,4,6-tris (3,5-di-t
-Butyl-4-hydroxybenzyl) benzene, tris- (3,5-di-t-butyl-4-hydroxybenzyl) -isocyanurate, N, N'-bis [3- (3,3
5-di-t-butyl-4-hydroxyphenyl) propionyl] hydrazinedibutylhydroxytoluene, 4,
4'-butylidene bis- (6-t-butyl-3-methylphenol), 2,2'-methylenebis- (4-methyl-6-t-butylphenol), 1,3,5-tris (3 ', 5') -Di-t-butyl-4'-hydroxybenzyl) -S-triazine-2,4,6 (1H, 3H, 5
H) -trione, 1,1,3-tris (2-methyl-4)
-Hydroxy-5-t-butylphenyl) butane, 4,
4'-butylidene bis (3-methyl-6-t-butylphenol), n-octadecyl-3- (4'-hydroxy-3 ', 5'-di-t-butylphenyl) propionate, tetrakis [methylene-3- ( 3 ', 5'-di-
t-butyl-4-hydroxyphenyl) propionate] methane, 2,2-thio-diethylenebis [3-
(3,5-di-t-butyl-4-hydroxyphenyl)
Propionate], 3,9-bis [1,1-dimethyl-
2 {β- (3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxyethyl] -2,4
8,10-tetraoxaspiro [5,5] undecane,
And 1,3,5-trimethyl-2,4,6 tris (3,3
Mention may be made of 5-di-t-butyl-4-hydroxybenzyl) benzene.

Further, as the sulfur-based stabilizer, 3,3'-
Thiobispropionic acid didecyl ester, 3,3'-
Thiobispropionic acid dioctadecyl ester, bis [2-methyl-4- {3-n-alkylthiopropionyloxy} -5-t-butylphenyl] sulfide, tetrakis [methylene-3- (dodecylthio) propionate] methane, ditridecyl Thiodipropionate,
Use of thioether type antioxidants such as 4,4'-thiobis- (6-t-butyl-3-methylphenol), dilaurylthiodipropionate, distearylthiodipropionate and dimyristylthiodipropionate be able to.

Further, (D) the resin composition of the present invention may be blended with various inorganic fillers such as fibrous, powdery and tabular particles depending on the purpose of use. As a fibrous filler,
Inorganic fibrous substances such as glass fiber, carbon fiber, silica fiber, silica-alumina fiber, alumina fiber, asbestos fiber, boron nitride fiber, silicon nitride fiber, boron fiber, potassium titanate and wollastonite can be used. Examples of the powdery or plate-like filler include carbon black, graphite, silica, glass beads, milled glass fiber, calcium silicate, aluminum silicate, talc, mica, iron oxide, titanium oxide, antimony trioxide, molybdenum disulfide and the like. To be These fillers can be used alone or in combination of two or more. Further, as the inorganic filler used in the present invention, those subjected to various surface treatments depending on desired physical properties can be used.

In the present invention, the composition of the resin composition is as follows. That is, (A) melt-processable polyamide resin 90 to 50% by weight, preferably 90 to 60% by weight, more preferably 90 to 70% by weight, and (B) modified polyolefin resin 10 to 99% by weight and the above (A). Polyamide resin and / or polyamide resin having a melting point lower than 1 to 90% by weight of masterbatch resin 10 to 50% by weight, preferably 10 to 40% by weight, more preferably 1
0.001 to 5 parts by weight of (C) phosphite ester, phosphoric acid ester, phenol-based and sulfur-based heat stabilizer, preferably 0.001 to 100 parts by weight of a resin component consisting of 0 to 30% by weight. To 1 part by weight, more preferably 0.00
1 to 0.3 parts by weight.

The content of the modified polyolefin in the master batch resin (B) is preferably 30 to 99% by weight, more preferably 50 to 99% by weight. The masterbatch is prepared and added in order to suppress the generation of mold deposits and improve the sliding characteristics, and there is no problem if it is within the above range, but from the viewpoint of friction and wear characteristics and physical properties, it is 10% by weight or less. The effect of improving the friction and wear characteristics is small, and if the content exceeds 50% by weight, the mechanical strength is remarkably reduced.

Further, with respect to the gel fraction of the masterbatch, if the gel fraction is less than 10% by weight, the effect of suppressing the deposit is small, and if it is more than 90% by weight, the dispersion in the resin becomes very bad and the physical properties are deteriorated. It can happen. Therefore, the gel fraction must be in the range of 10 to 90% by weight, preferably 20 to 60% by weight, more preferably 20 to 50% by weight.

To knead the components (A), (B) and (C), first, the modified polyolefin resin of the component (B) and the polyamide resin are kneaded to prepare the component (B), and this is mixed with the component (A). Knead. By thus kneading the modified polyolefin resin with the polyamide resin in two steps, a resin composition having excellent mechanical properties can be obtained.

The phosphite ester, phosphoric acid ester, phenolic stabilizer and sulfur stabilizer of component (C) are added at the time of kneading component (A) and component (B) in order to avoid thermal decomposition. In general, when a stabilizer with little decomposition is used, it may be added during preparation of the masterbatch resin. Furthermore, in the resin composition of the present invention, other thermoplastic resin is supplementarily added as a sliding component other than the masterbatch added as the friction and wear resistant component within a range not impairing the effects of the present invention. Is also good. The thermoplastic resin used in this case is not particularly limited, but examples thereof include fluororesin, ABS, and elastomer such as silicone rubber. Further, these thermoplastic resins can be used as a mixture of two or more kinds.

Further, known additives such as ultraviolet absorbers such as resorcinol, salicylate, benzotriazole and benzophenone, antistatic agents, halogen-based and phosphorus-based flame retardants, other lubricants and colorants are added to the resin composition of the present invention. The agent can also be appropriately added depending on the required performance as long as the effect of the present invention is not impaired. The present invention will be described below with reference to examples, but the present invention is not limited to the following examples.

[0027]

Example A masterbatch was prepared by kneading a modified polyolefin (B) having a composition shown in Table 1 and a polyamide having a lower melting point than that of (A) polyamide with a conventional extruder. This masterbatch was subjected to Soxhlet extraction with hot xylene for 12 hours, the extraction residue was dried at 80 ° C. for 24 hours, and the weight was measured to calculate the gel fraction.

Using this masterbatch, a JIS standard test piece having the composition shown in Table 2 was formed at a cylinder temperature of 290 ° C., and its physical properties were evaluated. Also, using a mold for manufacturing gears, the cylinder temperature is 290 ° C. and the mold temperature is 90.
Continuous production at 6 ° C for 6 hours, visually observing the mold deposit attached to the mold at that time, ◎ (none), ○
The evaluation was made in four grades: (nearly none), Δ (with adhesion), and × (strong adhesion).

The sliding characteristics were evaluated by cutting a JIS standard test piece sheet into 3 cm square pieces and using a ring-on-disk type abrasion tester. The test is 2 of SUS45C
The pin ring was performed at 750 rpm and a load of 20 kg.
The amount of wear per hour was calculated from the weight reduction of the sample after the test. The modified polyethylene of this example is a modified polyethylene containing active silane group manufactured by Mitsubishi Chemical Co., Ltd., a product name LINKRON (grade: HF700N) and a maleic anhydride modified polyethylene, and a product name MMHD (grade :), which are specially treated. Used as is. In particular, regarding the water content of wrinkle, the water content was controlled by leaving it in an atmosphere at 23 ° C. and a humidity of 50% and changing the standing time.

Polyamide 66 (grade: CM3, manufactured by Toray Industries, Inc.) is used as the polyamide resin (A) in the present embodiment.
001 N, melting point 265 ° C.) and used as such. The soft nylon used to make the masterbatch is ATO
CHEM nylon 11 (trade name: Rilsan, melting point 1
It was used as it was without any treatment at 85 ° C. The inorganic filler of this example has a diameter of 10 μm and an average fiber length of 6 m.
m manufactured by Nippon Electric Glass Co., Ltd. using an epoxy-based sizing agent was used. As the phosphite of this example, the trade name: Irgaphos 168 manufactured by Ciba-Geigy was used as it was.

[Comparative Example] The modified polyolefin of the masterbatch was prepared by using an ordinary unmodified high-density polyethylene (high-density polyethylene manufactured by Mitsubishi Chemical Co., trade name: Mitsubishi Polyethylene (grade: JY20, MFR = 9 and HY330B, MF).
The same evaluation as in the example was carried out except that R = 0.6) was changed.

[0032]

[Table 1]

[0033]

[Table 2]

Claims (4)

[Claims] 1. (A) Melt-processable polyamide resin 9
0 to 50% by weight, and (B) modified polyolefin resin 10
To 99% by weight of the above (A) polyamide resin and / or polyamide resin having a melting point lower than that (1) to 90%
Masterbatch resin 10 to 50 kneaded with
% Of (C) phosphite ester, phosphoric acid ester, phenol-based stabilizer or sulfur-based heat stabilizer with respect to 100 parts by weight of the total amount of the above components (A) and (B). A polyamide resin composition containing 5 to 5 parts by weight. 2. The masterbatch resin is thermal xylene 12
The polyamide resin composition according to claim 1, wherein the insoluble gel after time extraction is 10 to 90% by weight. 3. The components (A), (B), (C) and (D)
The thermoplastic resin composition according to claim 1, wherein an inorganic filler is added. 4. A sliding member formed by molding the polyamide resin composition according to claim 1.