JPH0543795A - Resin form - Google Patents

Abstract

PURPOSE:To provide the title form excellent in mechanical strength, low in coefficient of friction, producing no frictional noise, and substantially improved in critical PV value. CONSTITUTION:The objective composition can be obtained by incorporating 100 pts.wt. of a composition comprising (A) 20-95wt.% of a polyamide resin 5000-100000 in number-average molecular weight (e.g. nylon 4), (B) 3-40wt.% of a modified polyolefin resin prepared by adding to a blend of B1: 80-90wt.% of a polypropylene resin and B2: 10-20wt.% of a high-density polyethylene resin B3: 0.1-5wt.% of an acid anhydride (e.g. maleic anhydride), and (C) 1-70wt.% of a unmodified polyolefin resin (e.g. polyethylene) with (D) 5-150 (pref. 1-100) pts.wt. of an inorganic filler (e.g. glass fiber).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin molding having excellent mechanical strength, a low friction coefficient and a high limit PV value.

The thermoplastic resin molded product of the present invention is a wear-resistant molded product with less frictional noise, and is molded with sliding friction under high load such as gears, cams, chain guides and gears of automobiles. It is useful as a body.

[0003]

2. Description of the Related Art Recently, the field of application of plastic sliding members has been expanded, and bearings that are non-lubricated and are subject to severe friction under high load, bushings used under high ambient temperature conditions, and light and thin parts. The field of application is expanding to fields such as thin-walled sliding parts due to shortening and miniaturization, and performance requirements for plastic sliding members are becoming severe.

Polyamide resins are used in many fields by taking advantage of their mechanical properties, heat resistance, electrical properties and sliding properties. Recently, due to the weight reduction of automobiles and the rationalization of the assembly process, they have come to be used as automobile parts instead of metal.

However, when a polyamide resin is used for a sliding member with friction such as gears, pulleys and chain guides used in a severe environment in the engine room of an automobile, it has a higher load and sliding than metal. Softening occurs due to sliding frictional heat under velocity conditions, and the limiting PV value is
Small enough to be used for purposes. The amount of resin wear is large,
Inferior in durability when used for a long time. Coefficient of friction
Changes with friction speed, does not show stable sliding characteristics,
There were problems such as frictional noise, and it could not be used for parts that required high sliding performance.

Up to now, the mechanical strength and the limiting PV value have been improved to some extent by blending polyamide resin with carbon fiber (JP-A-49-18782), and potassium titanate fiber and high-density polyethylene have been blended. Although it is disclosed that the kinematics are improved (Japanese Patent Laid-Open No. 2-54853), there is no definite description about reduction of the friction coefficient and friction noise at low friction linear velocity, and heat resistance and mechanical strength are excellent. Further, a thermoplastic resin molded article having a low friction coefficient and no frictional noise was not known.

[0007]

DISCLOSURE OF THE INVENTION The present invention provides a resin molded product having a low coefficient of friction, a small coefficient of linear velocity dependency of the coefficient of friction, a high limit PV value, excellent mechanical strength, and no frictional noise. The purpose is that.

[0008]

Means for Solving the Problems As a result of intensive investigations by the present inventors, a composition obtained by blending a resin composition comprising a polyamide resin and a specific polyolefin with an inorganic filler lowers the friction coefficient, and further The present invention has been achieved by finding out that there is little friction noise during movement. That is, the present invention includes (A) 20 to 95% by weight of polyamide resin, (B) 80 to 90% by weight of polypropylene resin, and 10 to 10% of high-density polyethylene resin.
The acid anhydride is added to the mixture consisting of 20% by weight of 0.1 to 5.0.
Modified polyolefin resin obtained by adding 3 wt%
40% by weight, and (C) unmodified polyolefin resin 1
The present invention relates to a resin molded product composed of 100 parts by weight of a thermoplastic resin composition containing 70 to 70 parts by weight and 5 to 150 parts by weight of an inorganic filler.

The thermoplastic resin molding of the present invention is a molding obtained by melting and mixing a polyamide resin, a specific polyolefin resin and an inorganic filler. The polyamide resin (A) used in the present invention is as follows: , Nylon 4, nylon 6, nylon 8, nylon 9, nylon 10, nylon 11, nylon 12, nylon 46, nylon 66, nylon 610, nylon 612, nylon 1212 and other aliphatic polyamides and nylon 4T (T: terephthalic acid) , Nylon 4I (I: isophthalic acid), nylon 6
Examples thereof include semi-aromatic polyamides such as T, nylon 6I, nylon 12T, nylon 12I, etc., and mixtures and copolymers thereof. The method for producing the above resin can be carried out using a conventional technique. For example, solution polymerization, melt polymerization, interfacial polymerization, etc. can be illustrated. The molecular weight of the above resin is preferably 5,000 to 100,000, more preferably 1 in number average molecular weight.
It is from 0000 to 50,000. Those having a number average molecular weight of 5,000 or less have low mechanical strength,
If it is 00 or more, the fluidity during molding becomes poor.

The modified polyolefin (B) referred to in the present invention
Is obtained by adding 0.1 to 5.0% by weight of acid anhydride to a resin mixture consisting of 80 to 90% by weight of polypropylene resin and 10 to 20% of high-density polyethylene resin. Examples of the polypropylene resin used here include polypropylene, an ethylene propylene copolymer, an ethylene propylene diene copolymer, and the like.
It is preferably about 1.0 g / 10 minutes. Further, as the high-density polyethylene resin used here, MFR10
It is preferably about 25 g / 10 minutes. Examples of acid anhydrides used for modifying these polyolefins include maleic acid, succinic acid, itaconic acid, and acid anhydrides of hymic acid. Of these, maleic anhydride is preferably used. The amount of high-density polyethylene resin in the modified polyolefin resin is 10-2
The reason why the amount is limited to 0% by weight is that if the amount is less than 10% by weight, the decrease in the molecular weight upon modification with an acid anhydride is large,
This is because if it exceeds 20% by weight, the weld strength of the finally obtained molded article will be low.

The reason for setting the addition amount of the acid anhydride of the modified polyolefin resin to 0.1 to 5.0% by weight is that if it is less than 0.1%, the reactivity with the amino terminal group of the polyamide resin becomes poor and the weld strength is weakened. In addition, impact resistance is not expressed. This is because if the amount exceeds 5% by weight, not only the quantitative effect is not recognized, but also problems such as gelation and coloring occur.

The modified polyolefin resin can be produced, for example, by preliminarily determining a predetermined amount of polypropylene resin, polyethylene resin, maleic anhydride and peroxide, and mixing them with a blender or the like to melt-mix them with a twin-screw extruder. However, the method is not limited to this method.

The unmodified polyolefin (C) used in the present invention includes polyethylene, polypropylene, polybutene, polyhexene, ethylene propylene copolymer,
Ethylene propylene diene copolymer, styrene butadiene copolymer, hydride of styrene butadiene copolymer,
Examples thereof include hydrides of styrene isoprene copolymer. The components (A), (B) and (C) are mixed in proportions of 20 to 95% by weight of polyamide resin, 3 to 40% by weight of modified polyolefin resin, and 1 of unmodified polyolefin resin.
~ 70 weight. The reason why the amount of the polyamide resin is set to 20 to 95% by weight (preferably 30 to 80% by weight) is that if the compounding amount is less than the lower limit, the mechanical properties originally possessed by the polyamide resin (A) are deteriorated. The reason is that if the amount is more than the upper limit, the slidability is not improved.

Similarly, the reason why (B) is set to 3 to 40% by weight (preferably 15 to 35% by weight) is that if the compounding amount is less than the lower limit, (A) and (C) depend on the compounding of (B). This is because the effect of improving compatibility is not seen, and in particular the weld strength is reduced, and when the amount is more than the upper limit, the quantitative effect due to the addition of (B) is not recognized.

Further, the reason for setting (C) to 1 to 70% by weight (preferably 10 to 60% by weight) is that when the content is less than the lower limit, the effect of reducing the sliding performance, particularly the friction coefficient is recognized. This is because there is no heat resistance, and when the amount is more than the above upper limit, deterioration of heat resistance is recognized.

The thermoplastic resin composition of the present invention comprising the components (A), (B) and (C) is a composition in which the average dispersed particle size of the components (B) and / or (C) is 20 μm or less. .. When the average dispersed particle diameter exceeds 20 μm, not only the weld strength is significantly lowered, but also the stable friction coefficient is not exhibited. A preferable average dispersed particle size is 10 μm or less. More preferably, it is 5 μm or less.

When the inorganic filler (D) of the present invention is compounded in a resin composition composed of polyamide resin / modified polyolefin resin / unmodified polyolefin resin, not only the rigidity is improved but also the friction at a low friction speed is obtained. It is intended to reduce the coefficient, for example, glass fiber, carbon fiber, metal fiber, aramid fiber, potassium titanate,
Fibrous reinforcing agents such as asbestos, carbonized diatom, ceramic fiber, nitrided diatom, barium sulfate, calcium sulfate,
Kaolin, clay, bilophyllite, bentonite, sericite, zeolite, mica, mica, nepheline sinite, talc, atharbulite, wollastonite, PMF, ferrite, calcium silicate, calcium carbonate, magnesium carbonate, dolomite, antimony trioxide. Examples include reinforcing fillers such as zinc oxide, titanium oxide, magnesium oxide, iron oxide, molybdenum disulfide, graphite, gypsum, glass beads, glass powder, quartz, and quartz glass. The blending amount of the filler is 5 to 15
It is 0 part by weight, preferably 10 to 100 parts by weight. 15
If the amount exceeds 0 parts by weight, the workability is deteriorated, so that the surface of the molded product is significantly damaged, and if the amount is less than 5 parts by weight, the rigidity is not improved and the effect of improving the friction coefficient at low friction speed is not recognized.

Additives to be added to the thermoplastic resin of the present invention, such as heat stabilizers, light stabilizers, UV absorbers, lubricants, nucleating agents, antioxidants, dyes, pigments and interfaces. It is not particularly limited to blend an activator, a plasticizer, another polymer, etc., if necessary.

The resin molding of the present invention is prepared by a technique such as a Brabender, a kneader, a bumper mixer, a twin-screw or single-screw extruder.

The resin molding of the present invention is molded and used by techniques such as injection molding, extrusion molding and blow molding.

[0021]

EXAMPLES Examples of the present invention will be shown below, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded.

The raw materials and test methods used in the present invention are shown below.

(1) Raw material Polyamide resin Polyamide 66 resin (manufactured by Asahi Kasei Kogyo Co., Ltd., number average molecular weight of about 20,000) Polypropylene resin PP homopolymer MFR = 0.5 manufactured by Asahi Kasei Co., Ltd. High density polyethylene resin Suntech manufactured by Asahi Kasei Co., Ltd. HDPE MFR = 19 Polyolefin resin Asahi Kasei Corporation PP homopolymer MFR = 30 Maleic anhydride NOF Corporation crystal MAN Organic peroxide NOF Corporation Perhexa 25B glass fiber Asahi Fiber Glass Co., Ltd. JAFT-IIA (2) Test method Tensile test (1/8 inch) A test was conducted according to ASTM D638.

Bending test (1/8 inch) A test was conducted according to ASTM D790.

Friction and Wear Test The friction and wear tester was a Suzuki type friction and wear tester. The measurement condition is that the surface pressure of the molded product is 10 kg / cm ²
After confirming that the coefficient of friction was stable for 15 minutes, the linear velocity was changed to the next linear velocity to be measured. The friction coefficient in Table 1 shows the friction coefficient of the limit PV value. The friction coefficient in Table 2 shows the friction coefficient of the measured linear velocity.

The method for producing the modified polyolefin resin (B) used in Examples and Comparative Examples is shown below.

Production Example 1 The modified polyolefin resin (B) used in Examples 1 to 3 and Comparative Examples 5 and 7 was 85 parts by weight of polypropylene resin.
Mix 1 parts by weight of polyethylene resin to prepare mixture 1
To 100 parts by weight, 0.5 parts by weight of maleic anhydride and 0.2 parts by weight of organic peroxide were added and dry blended to obtain a 70 mmφ single screw extruder (L / D = 3.
At 0.5), the temperature of the cylinder was 180 ° C. and the number of rotations of the screw was 80 rpm. Table 1 shows the amount of maleic anhydride grafted on the modified polyolefin resin (B) thus obtained.

Production Example 2 The modified polyolefin resin (B) used in Comparative Example 3 is
Production Example 1 except that maleic anhydride was changed to 0.2 part by weight
A resin pellet was obtained by the same procedure as above. Table 1 shows the amount of maleic anhydride grafted on the modified polyolefin resin (B) thus obtained.

Production Example 3 The modified polyolefin resin (B) used in Comparative Example 4 is
Produced in the same manner as in Production Example 1, except that the polypropylene resin was 80 parts by weight and the polyethylene resin was 20 parts by weight.
Resin pellets were obtained. Table 1 shows the amount of maleic anhydride grafted on the modified polyolefin resin (B) thus obtained.
Shown in.

Example 1 65 parts by weight of polyamide resin, 25 parts by weight of modified polyolefin resin prepared in Production Example 1, polypropylene resin 1
12 parts by weight of glass fiber was added to 100 parts by weight of resin consisting of 0 parts by weight, PCM of Ikegai Tekko KK
Resin pellets obtained by melting and mixing with a -45 mmφ twin-screw extruder (L / D = 33.5) PS
Injection molding was performed by a -40E injection molding machine to prepare test pieces in each test. The results are shown in Tables 1 and 2.

Example 2 Example 1 was repeated except that the glass fiber of Example 1 was changed to 26 parts by weight. The results are shown in Tables 1 and 2.

Example 3 Example 3 was repeated except that the glass fiber of Example 1 was changed to 50 parts by weight. The results are shown in Tables 1 and 2.

Comparative Example 1 Example 1 was repeated except that 100 parts by weight of the polyamide resin was used. The results are shown in Tables 1 and 2.

Comparative Example 2 Example 1 was repeated except that 65 parts by weight of polyamide resin and 35 parts by weight of polyolefin resin were used.
The results are shown in Table 1.

Comparative Example 3 The procedure of Example 1 was repeated, except that 65 parts by weight of the polyamide resin and 35 parts by weight of the modified polyolefin resin prepared in Production Example 2 were used. The results are shown in Table 1.

Comparative Example 4 The procedure of Example 1 was repeated except that 65 parts by weight of the polyamide resin and 35 parts by weight of the modified polyolefin resin prepared in Production Example 3 were used. The results are shown in Table 1.

Comparative Example 5 The procedure of Example 1 was repeated, except that 65 parts by weight of the polyamide resin and 35 parts by weight of the modified polyolefin resin prepared in Production Example 1 were used. The results are shown in Table 1.

Comparative Example 6 The same as Example 1 except that 65 parts by weight of the polyamide resin, 10 parts by weight of the modified polyolefin resin prepared in Production Example 1 and 25 parts by weight of the polyolefin resin were used, and a 70 mmφ single screw extruder was used. Went to. The results are shown in Table 1.

Comparative Example 7 The procedure of Example 1 was repeated, except that the glass fiber of Example 1 was 0 part by weight (no addition). The results are shown in Tables 1 and 2.

[0040]

[Table 1]

[0041]

[Table 2]

[0042]

EFFECT OF THE INVENTION The resin molded product of the present invention comprising a polyamide resin, a polyolefin resin and an inorganic filler has the effect of reducing the friction coefficient of the maximum value depending on the linear velocity and eliminating frictional noise. Furthermore, since it does not lower the limit PV value, has no frictional noise and has a low friction coefficient, and has excellent mechanical strength and rigidity, it is used for automobile parts (starter motor gear, wiper motor gear, chain guide). ) And gears for industrial robots and the like.

Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location C08L 23/26 LDA 7107-4J

Claims (1)

[Claims] 1. A mixture of (A) 20 to 95% by weight of polyamide resin, (B) 80 to 90% by weight of polypropylene resin and 10 to 20% by weight of high-density polyethylene resin and 0.1 to 5% of acid anhydride. From 100 parts by weight of a thermoplastic resin composition consisting of 3 to 40% by weight of a modified polyolefin resin obtained by adding 0% by weight and (C) 1 to 70% by weight of an unmodified polyolefin resin and 5 to 150 parts by weight of an inorganic filler. Resin molded product.