JPH0253464B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for producing a polyamide resin composition, and more specifically to a polyamide resin with excellent screw penetration properties, injection moldability of the resulting polyamide resin composition, and friction and wear resistance. The present invention relates to a method for producing a composition. (Prior art) In general, polyamide resin has superior self-lubricating properties compared to metals, has a low coefficient of friction, good friction and wear resistance, is lightweight, and produces less noise when sliding, so it is used in bearings, gears, etc.
Extremely useful as lube-free parts such as rollers, cams, and guide rails. However, when viewed as a sliding part, there are limits.
Currently, it is limited to low-load applications because its PV value is relatively small. Note that the limit PV value here is generally determined by the constant surface pressure (Kg/cm ² ) of the bearing material and the circumferential speed V (m/cm 2 ).
Indicates the limit value of the load above which the material will melt or seize. Therefore, the larger the limit PV value, the better the friction and wear resistance characteristics, which means that the material can withstand high loads. For this reason, in order to improve the friction and wear characteristics of polyamide compositions, lubricants such as molybdenum disulfide, graphite, oil, and wax have been added to polyamide compositions. (Problems to be Solved by the Present Invention) However, if the above-mentioned lubricant is added, the screw will not penetrate into the screw during extrusion, and sufficient extrusion molding will not be possible, and even if the obtained resin composition However, there was a problem in injection moldability, that is, a part of the resin metered during injection flowed back into the cylinder, resulting in a shot shot in the molded product, and stable extrusion molding and injection molding could not be performed. Alternatively, there are problems with the surface properties of the molded product, and there is a tendency for the impact resistance to decrease, so problems remain. An object of the present invention is to solve the problems of the prior art described above, and to provide a method for producing a polyamide resin composition particularly excellent in screw penetration properties, injection moldability, and friction and wear resistance. (Means for Solving the Problems) The features of the present invention are as follows: (1) 20 to 90% by weight of polyamide resin (2) Polyamide in which 1 to 10% by weight of microcrystalline wax is uniformly dispersed in advance resin 5
~60% by weight (3) 5 to 20% by weight of ionomer By using mixed resin pellets obtained by melting and kneading the three components, resin moldings can be easily produced by injection molding, extrusion molding, and compression molding. It has excellent screw penetration properties, injection moldability, friction and wear resistance, and impact resistance. Examples of the polyamide resin used in the present invention include nylon-6, nylon-11, and nylon-12. In addition, the microcrystalline wax uniformly dispersed in the polyamide resin used in the present invention is mainly composed of isoparaffins with a melting point of 75 to 100°C and a carbon number of 40 to 50, and contains naphthenes, aromatics, and normal paraffins. Molecular weight 500-1000 including small amounts
It is a hydrocarbon mixture of Examples of commercially available products include the following. S/V2305 (mp: 75.7℃)
(manufactured by Mobil Chemical), ML-445 (mp: 76.1
°C) (manufactured by Witco Chemical), Serataku-104
(mp: 76.1℃) (manufactured by Petrolite), Smaxx
180 (mp: 82.2-87.8℃) (manufactured by Etsuso Standard), Hi-Mic1080 (mp: 83.9℃) (manufactured by Nippon Seirosha), Starwax-100 (mp: 85.0℃) (manufactured by Petrolite), Hard Wax 1561 (mp: 96.0℃) (manufactured by Rozier Reed), Hi-Mic209, 5 (mp: 96.1
℃) (manufactured by Nippon Seirosha), etc. Further, the microcrystalline wax-containing polyamide resin used in the present invention can be obtained by the method described in Japanese Patent Publication No. 52-39878. That is, alkali metals, alkaline earth metals, and alkali or alkaline earth metal hydrides, hydroxides, oxides, Microcrystalline wax is uniformly dispersed during the anionic polymerization of ε-caprolactam in the presence of an anionic polymerization catalyst consisting of alkyl compounds, aryl compounds, etc., and anionic polymerization promoters such as acyl compounds, isocyanates, triazines, carbodiimides, etc. It is made into powder, granules, or flakes to make it easier to mix with other resins. Further, the ionomer used in the present invention is a resin in which the molecules of an ethylene-methacrylic acid copolymer are cross-linked with metal ions, and examples thereof include Himilan 1554 and Himilan 1555 (manufactured by Mitsui Polychemical Co., Ltd.). A proposal to blend these ionomers with 6-nylon is published in Japanese Patent Application Laid-Open No. 61-2664, USP No.
Although it is disclosed in Japanese Patent No. 3845163, it is not intended to provide a polyamide resin composition that has excellent screw penetration properties, injection moldability, and excellent friction and wear properties, which is the objective of the present invention, but to improve impact resistance. It was intended to. The effective equivalent weight of the amount of microstalline wax (hereinafter abbreviated as MCW) added to the polyamide resin composition is preferably 0.5 to 6.0% by weight, and 6% by weight.
If it exceeds this value, the extruded resin will not penetrate into the injection molding machine or the screw surface of the extrusion molding machine or the inside of the cylinder, and there will be a strong tendency for the resin to flow back into the cylinder during injection molding.
In addition, there is a problem that mechanical strength is reduced. Further, if it is less than 0.5% by weight, sufficient friction and wear resistance properties cannot be exhibited. Further, the amount of the ionomer added is 5 to 20% by weight, and if it exceeds 20% by weight, it leads to a decrease in mechanical strength and a decrease in friction and wear resistance, which causes practical problems. Also, the weight ratio of MCW and ionomer is 1/
The ratio is preferably 3 or less; if it exceeds 1/3, for example, when the three components are melt-kneaded using a twin-screw extruder, not only will sufficient penetration into the screws not be obtained, but the molded product will suffer from delamination ( There is a strong tendency for phase separation to occur. This means that the weight ratio of MCW/ionomer is 1/
This is thought to be due to the fact that when it exceeds 3, the ionomer swells to the extent that it separates into two phases from the nylon due to the MCW. When the MCW/ionomer weight ratio is less than 1/3, the ionomer is sufficiently compatible with the nylon, and the ionomer absorbs the microcrystalline wax and reduces the tendency to bite into the screw when melt-kneading the three components. make it good,
It is also believed that the injection moldability of the obtained resin composition is improved. EXAMPLES The present invention will be described in detail below with reference to Examples, but it goes without saying that the present invention is not limited thereto. Example 1 6-nylon (Unitika FL-1) 75% by weight
and MCW (Smaxx manufactured by Etsuso Standard Co., Ltd.)
20% by weight of crushed 3-4 mm square flakes of 6-nylon dispersed with 6% by weight of 180) and 5% by weight of ionomer (Himilan 1554 manufactured by Mitsui Polychemicals).
Shake well beforehand in a polyethylene bag and dry blend, melt and knead with a twin-screw extruder (PCM-45 manufactured by Ikegai Iron Works). The resulting strands are made into pellets with a pelletizer and injected to obtain test pieces. It was subjected to molding. The test pieces obtained (tensile test piece, bending test piece, Izod test piece, Matsubara thrust test piece) all had perfect shapes. Table 1 shows the screw penetration, injection moldability, limit PV value, and Izot impact value of the twin-screw extruder. The friction and wear test was carried out using Toyo Baldwin KK's Matsubara type friction and wear tester, using cylindrical steel (S45C) as the mating material, in all non-lubricated conditions, and at a circumferential speed (V) of 15 m/min. The test was conducted by changing the surface pressure (P) every 10 minutes while keeping the pressure constant at min. The critical PV value was determined when the load became impossible to control. Example 2 In Example 1, 6-nylon (manufactured by Unitika)
A test piece was obtained in the same manner as in Example 1, except that 45% by weight of FL-1) and 10% by weight of the ionomer (Himilan 1554 manufactured by Mitsui Polychemicals) were used. All test pieces had perfect shape. 1st
The table shows the screw penetration, injection moldability, limit PV value, and Izot impact value of the twin-screw extruder. Example 3 In Example 1, 6-nylon (manufactured by Unitika)
FL-1) 60% by weight, 6% by weight of MCW (Smax 180 manufactured by Etsuo Standard Co., Ltd.) dispersed
- A test piece was obtained in the same manner as in Example 1, except that 25% by weight of crushed 3-4 mm square flakes of nylon and 15% by weight of an ionomer (Himilan 1554 manufactured by Mitsui Polychemicals) were used. All test pieces had perfect shape. Table 1 shows the screw penetration properties of the twin-screw extruder.
Shows injection moldability, limit PV value, and Izod impact value. Comparative example 1 6-nylon (Unitika FL-1) alone 2
The mixture was melt-kneaded using a screw extruder, made into pellets using a pelletizer, and used for injection molding. All the test pieces obtained had perfect shapes. Table 1 shows the screw penetration properties of the twin-screw extruder.
Shows injection moldability, limit PV value, and Izod impact value. Comparative example 2 6-nylon (Unitika FL-1) 70% by weight,
MCW (Smaxx manufactured by Etsuso Standard Co., Ltd.)
30% by weight of crushed 3-4 mm square flakes of 6-nylon dispersed with 6% by weight of 180) were dry-blended in advance in a polyethylene bag, melt-kneaded using a twin-screw extruder, and the resulting strands were processed using a pelletizer. It was made into pellets and used for injection molding to obtain test pieces. Only the Izot impact test piece was obtained in perfect shape, but all the other test pieces were shot shots. Table 1 shows the screw penetration, injection moldability, and Izod impact value of the twin-screw extruder.

【table】

[Table] (b) Shot shot (effect) As described above, according to the production method of the present invention, a predetermined amount of ionomer is mixed into the polyamide resin in which the polyamide resin and microstalline wax are uniformly dispersed, and the resulting product is transferred to the screw. As a result, the polyamide resin composition can be melted and kneaded without any resistance, and the injection and extrusion moldability of the resulting polyamide resin composition is also improved, and the friction and wear resistance of the molded product is also improved. It has the effect of

Claims (1)

[Scope of Claims] 1. 20 to 90% by weight of polyamide resin and 1 to 10% by weight of polyamide resin in advance.
Three components consisting of 5-60% by weight of polyamide resin in which % by weight of microcrystalline wax is uniformly dispersed, and 5-20% by weight of ionomer,
A method for producing a polyamide resin composition characterized by uniformly melting and kneading. 2 The amount of microcrystalline wax added in the polyamide resin composition is 1/3 that of the ionomer.
Claim 1 characterized in that:
A method for producing a polyamide resin composition as described in Section 1.