WO2003054066A1 - Polyamide based formed article excellent in sliding property - Google Patents

Abstract

A polyamide based formed article excellent in sliding property which comprises a polyamide type resin composition comprising a polyamide type resin and a silicone compound having an OH group in a side chain thereof or a polyamide type resin and a crystalline resin having a silicone moiety grafted thereto in a side chain of the crystalline resin, wherein the article exhibits, in a repeating sliding test of a total load of 200 g and a stroke of 40 mm, an absolute value of the difference between the friction coefficient μ(1) at the first sliding and the friction coefficient μ(1000) at the 1000th sliding of 0.17 or less and both of μ(1) and μ(1000) of 0.25 or less. The polyamide based formed article is stainproof and is excellent in sliding property and further can be produced at a low cost.

Description

 Specification

 Polyamide molded body with excellent slidability

 Technical field

The present invention retains the excellent strength, impact resistance, heat resistance, and chemical resistance of a polyamide-based molded product, has extremely excellent sliding properties, and does not contaminate the surface of the molded product with a foil. The present invention relates to a polyamide-based molded article having excellent sliding properties in which the coefficient of friction does not change even after long-term repeated sliding.

 Background art

 Normally, polyamide resin has high crystallinity, so that it originally has good sliding characteristics. However, in recent years, various functions required for engineering plastics such as polyamide resins (hereinafter also referred to as engineering plastics) have become more sophisticated, and even higher sliding characteristics are required. Many studies have been made on improving the sliding properties of engineering plastics since ancient times, and solid lubricants such as molybdenum disulfide, graphite, and fluororesins, and various lubricants such as lubricating oils and silicone oils have been mainly used. It is being studied as a sliding modifier.

 Of these sliding modifiers, solid lubricants are resins that have inherently excellent sliding characteristics, such as polyamide resins.If you want to further improve the sliding characteristics, you will need to mix a large amount of solid lubricants. Yes, it significantly deteriorates the physical properties of the base such as a polyamide resin and is economically unpreferable because it contains a large amount of expensive solid lubricant.

On the other hand, liquid lubricants can impart effective sliding properties to engineering plastics and other resins with a relatively small amount, but in many cases, the compatibility with the base resin is poor, and the surface of the molded product is not lubricated with these liquid lubricants. In many cases, the use of these liquid lubricants will limit the use of resin products that have improved slidability. For example, the nylon 6 resin has a zollibilite parameter (SP value) of 12.7, and the silicone oil has a SP value of 7.3. If the SP values of the two are significantly different in this way, the compatibility is extremely poor and molded article contamination often occurs. Is not preferred.

 Disclosure of the invention

 The present invention has been made in view of the problems of the prior art, and imparts extremely excellent slidability while maintaining excellent strength, impact resistance, heat resistance, and chemical resistance of a polyamide-based molded article. It is another object of the present invention to manufacture a polyamide-based molded article excellent in sliding properties without contamination of molded articles at low cost.

 The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have finally completed the present invention.

 That is, the present invention

(1) A molded body made of a polyamide resin composition, and when the molded body and the stainless steel ball are repeatedly slid with a total load of 200 g and a stroke of 40 mm, the first sliding occurs. The absolute value of the difference between the friction coefficient (1) when moving and the friction coefficient (1000) at the time of the 1000th sliding is 0.17 or less, and both / z (l) and / (1000) 0.25 or less, a polyamide-based molded article having excellent slidability,

 (2) The polyamide-based molded article having excellent slidability described in (1) above, wherein the polyamide-based resin composition contains a polyamide-based resin and a silicone compound having an O H group in a side chain.

 (3) The polyamide-based molding having excellent slidability described in (1) above, wherein the polyamide-based resin composition contains a polyamide-based resin and a crystalline resin having a silicone compound in a side chain of 30% by weight or more by graft polymerization. Body,

 ポ リ ア ミ ド The slidable polyamide-based molded article according to ① above, wherein the polyamide-based resin composition contains a polyamide-based resin and a silicone compound having a polar group that reacts with the polyamide-based resin.

It is.

 Hereinafter, the present invention will be described specifically.

In the present invention, the polyamide resin has an acid amide bond (1-CONH-1) in the molecule. Specifically, ε-force prolactam, 6-amido Polymer or copolymer or blend obtained from nocaproic acid, ω-enantholactam, 7-aminoheptanoic acid, 11-aminoundecanoic acid, 9-aminononanoic acid, α-pyrrolidone, α-piperidone, etc. , Hexamethylene diamine, nonamethylene diamine, pendecamethylene, diamine, dodecamethylene diamine, metaxylylenediamine and other diamines and terephthalic acid, isophthalic acid, adipic acid, sebacic acid, etc. Examples include, but are not limited to, polymers, copolymers or blends obtained by polycondensation with an acid.

 In the present invention, those having a number average molecular weight of 7,000 to 30,000 are preferably used. If the number average molecular weight is 7,000 or less, the toughness decreases, which is not preferable. On the other hand, if it is more than 30,000, the fluidity decreases, which is not preferable.

 Various silicone compounds contained in the polyamide resin composition of the present invention are as follows.

 (1) Silicone compound with ΟΗ group in side chain

 One example is a silicone compound represented by the following general formula (I).

(CH ₃ ) ₃ Si () 3 no 3 (I)

(E0) _m- (P0) _n -R ² 0H

(In the general formula (I), R ¹ and R ² represent an alkyl group, EO represents ethylene oxide, and PO represents propylene oxide.) (2) Crystalline resin grafted with 30% by weight or more of a silicone compound It can be obtained by graft-polymerizing a reactive polyorganosiloxane onto a thermoplastic crystalline resin. In addition, as the crystalline resin, various types of polyethylene resin, ethylene / olefin resin, and the like are preferable, but are not limited thereto.

 (3) Silicone compound having a polar group that reacts with polyamide resinPolar groups such as amino group, hydroxyl group, hydroxyl group, acid anhydride group, and epoxy group that react with polyamide resin at both ends or one end of polyorganosiloxane. A silicone compound containing

 In the present invention, the silicone compound (1) and / or (2) is particularly preferably used.

 The amount of the silicone compound used in the present invention is 0.1 to 10 parts by weight, preferably 0.2 to 8 parts by weight, as a single silicone compound, based on 100 parts by weight of the polyamide resin.

 In the present invention, a compatibilizer may be added in order to improve the compatibility between the crystalline resin to which the silicone compound is grafted and the polyamide resin. When the crystalline resin is a polyethylene resin, it is preferable to add a maleic acid-modified polyethylene resin.

 In the present invention, reinforcing polyamides can be blended with the polyamide resin. Reinforcing inorganics are fibrous reinforcing materials such as glass fiber, carbon fiber, ceramic fiber, and various whiskers. Examples include powdered inorganic strengthening materials such as silica, alumina, talc, kaolin, quartz, powdered glass, myriki, and graphite. These reinforcing inorganic substances may be treated with a silane coupling agent as a surface treatment agent.

In addition, carbon black and copper oxide and / or halogenated alkali metal as weather resistance improvers used in ordinary polyamide resin compositions, phenol-based antioxidants as light or heat stabilizers, phosphorus compounds, Flame retardants, antistatic agents, pigments, dyes, etc. may be added as necessary. Next, as a method for producing a polyamide molded article having excellent slidability in the present invention, for example, the above-mentioned silicone compound and, if necessary, reinforcing inorganics and other additives are blended with a polyamide resin. It is obtained by melt-kneading pellets of the polyamide resin composition. Examples of the melting and kneading apparatus include a single screw extruder, a twin screw extruder, a pressure kneader, and the like, and a twin screw extruder is particularly preferable. A molded article is obtained from the pellet of the polyamide-based resin composition by using an injection molding machine or an extrusion molding machine.

 According to the present invention, while maintaining the excellent strength, impact resistance, heat resistance and chemical resistance of the polyamide-based molded article, it has extremely excellent sliding properties, and the surface of the molded article is not contaminated with oil or the like. Thus, a polyamide-based molded body whose friction coefficient does not fluctuate even after long-term repeated sliding can be obtained. BEST MODE FOR CARRYING OUT THE INVENTION

 Example

 Next, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

 In addition, each evaluation is the value measured by the following method.

 (1) Friction coefficient (): The friction coefficient () for repeated sliding was evaluated by measuring the frictional force under the following conditions and calculating by the following formula (1).

 Evaluation sample 2 mm flat plate

 Counterpart material 1/2 inch stainless steel ball

 2 0 0 g

 Sliding distance 4 O mm repeated sliding

 30 cycles / min

 Measurement temperature Room temperature (25 ° C, 65% RH)

(II) = (frictional force) / (full load) (1) (2) The presence of silicone contamination on the surface of the molded product

 Regarding the surface contamination (preed) of the polyamide molded product by the silicone compound, the evaluation sample was left in a constant temperature bath at 30 ° C and 95% RH for one week, and the surface of the sample was observed to check for contamination. It was judged with the naked eye. (Examples 1-3, Comparative Examples 1-3)

 Polyamide resins include nylon 6 (Toyobo Nylon T-800), silicone compounds having an OH group in the side chain, Paintant 54 (manufactured by Dowkoh Asia Ltd.), and crystallinity having a silicone compound in the side chain. As resin, MA-Yuichi Pellet SP-350 (crystalline resin is polyethylene, silicone compound content is 50% by weight, manufactured by Dow Corning Asia Co., Ltd.), and amorphous with silicone compound in the side chain SP-110 (amorphous resin is EVA, silicone compound content is 60% by weight, manufactured by Dowko Asia Co., Ltd.) as a water-soluble resin, and E-001 (maleic acid-modified polyethylene as a compatibilizer) Resin, manufactured by Mitsui Chemicals, Inc.), weighing each raw material at the ratios shown in Table 1, mixing them in a tumbler, kneading them at a temperature of 290 ° C with a twin-screw extruder, and After pelletizing Molding a flat plate of 2 mm in an injection molding machine to the evaluation sample. The cylinder temperature of the injection molding machine was 290 ^: the mold temperature was 80 ° C.

 Table 1 shows the above results.

 Example 1 is a case where a silicone compound having an OH group in a side chain is blended, and Examples 2 and 3 are a case where a silicone compound grafted to a crystalline resin is blended. In each case, both (1) and (1000) are small, and the difference between (1) and X (1000) is very small. In other words, it shows that it has extremely excellent slidability.

On the other hand, in Comparative Example 1, although the sliding characteristics of nylon 6 are exhibited, the initial / (l) is excellent, but the friction coefficient gradually increases as the sliding is repeated. Also, as shown in Comparative Example 3, when the silicone compound grafted to the amorphous resin ethylene / vinyl acetate (EVA) was blended, the sliding was repeated. table 1

注； ① （ ）* の数値は樹脂に含まれるシリコーン化合物の重量部 (pHr)を表す。

Note: ① The values in parentheses (*) indicate parts by weight (pHr) of the silicone compound contained in the resin.

② The difference in the coefficient of friction shows the absolute value.

It is not preferable because the coefficient of friction increases soon.

 Regarding the contamination (bleed) of the silicone compound on the surface of the polyamide molded article, there was no contamination with the silicone compound of any of the examples. This is probably because these silicone compounds have a relatively large molecular weight and improved compatibility with polyamide resins. Industrial applicability

 The polyamide molded article having excellent slidability according to the present invention can obtain an extremely stable coefficient of friction when repeatedly slid, and does not cause contamination of molded articles. In addition, since excellent sliding properties can be obtained without deteriorating the excellent properties of polyamide-based resin, various gears, guides, reels, etc. in the fields of home appliances, AV equipment, office supplies, and the automotive field It can be used in a wide range of fields, such as door-to-check levers and seat belt parts, greatly contributing to the industry.

Claims

The scope of the claims 1. A molded body made of a polyamide-based resin composition, and when the molded body and the stainless steel ball are repeatedly slid with a total load of 200 g and a stroke of 4 Omm, the first sliding occurs. The absolute value of the difference between the friction coefficient (1) at the time and the friction coefficient (1000) at the 1000th sliding is 0.17 or less, and both (l) and (1000) are 0.25. A polyamide molding having excellent slidability, characterized in that: 2. The polyamide-based molded article having excellent slidability according to claim 1, wherein the polyamide-based resin composition contains a polyamide-based resin and a silicone compound having an O H group in a side chain. 3. The polyamide-based molding having excellent slidability according to claim 1, wherein the polyamide-based resin composition contains a polyamide-based resin and a crystalline resin having a side chain of 30% or more by weight of a silicone compound by graft polymerization. body. 4. The polyamide-based molded article having excellent slidability according to claim 1, wherein the polyamide-based resin composition contains a polyamide-based resin and a silicone compound having a polar group that reacts with the polyamide-based resin.