JPH08134348A - Polyamide resin composition - Google Patents

Abstract

PURPOSE: To obtain a polyamide resin composition containing a nylon 46 resin, a silicate-based powdery inorganic filler and ultrahigh molecular weight polyethylene resin powder at a specific ratio, not exhibiting large abrasion to a flexible non-iron metal in sliding and excellent in sliding characteristics and useful for bearing components, etc. CONSTITUTION: This composition is composed of (A) 30-90wt.% of a nylon 46 resin, (B) 6-60wt.% of a silicate-based powdery inorganic filler such as baked kaolin and (C) 4-10wt.% of ultrahigh molecular polyethylene resin powder having >=10dl/g intrinsic viscosity 9146/28}η] measured in decalin solvent heated to 135 deg.C and capable of substantially passing all amount of the powder through 100 mesh sieve and passing through 350 mesh sieve in an amount of >=20% and having <=80μm average particle diameter.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyamide resin composition, and more particularly to a polyamide resin which has excellent sliding properties and which does not cause a large amount of wear particularly on a soft non-ferrous metal when sliding.

[0002]

BACKGROUND OF THE INVENTION Nylon 46 resin has excellent heat resistance and mechanical properties such as tensile strength and bending strength, and also has excellent fluidity and the like, and its value in use as a useful engineering plastic has attracted great attention. . In particular, it is used for sliding parts such as bearing parts, gear parts, and bearing retainers because it has excellent sliding characteristics such as wear resistance. However, in conventional sliding parts, the mating material that slides on the nylon 46 resin is limited to steel. This is because the nylon 46 resin reinforced with a silicate-based powdery inorganic filler or the like shows remarkable wear and wear (aggressiveness) when a soft non-ferrous metal material is used as a mating material during sliding. The term "aggressiveness" as used herein means a phenomenon in which a mating material is greatly worn during sliding. Also,
The soft non-ferrous metal means simple substances such as aluminum, copper, magnesium, zinc, lead, tin, gold and silver, and alloys of these metals.

[0003]

The present invention has been made in view of the above circumstances, and its purpose is nylon 4
While maintaining the excellent mechanical properties and heat resistance of 6 resin,
Its purpose is to reduce its sliding characteristics, particularly the aggressiveness to soft non-ferrous metal materials.

[0004]

Means for Solving the Problems The present inventors finally conducted the present invention as a result of intensive research and study for solving the above problems.

That is, the present invention relates to (A) nylon 46
Resin 30 to 90% by weight, (B) Silicate powdered inorganic filler
A polyamide resin composition comprising 6 to 60% by weight and (C) 4 to 10% by weight of an ultrahigh molecular weight polyethylene resin powder.

The present invention will be described in detail below.

The component (A) nylon 46 resin used in the present invention is obtained by condensation reaction using adipic acid or its functional derivative as the acid component and tetramethylenediamine or its functional derivative as the amine component. Although the main object is polyamide, it may be one in which a part of the adipic acid component or tetramethylenediamine component is replaced with another copolymer component.

Preferred embodiments of nylon 46 resin are JP-A-56-149430 and JP-A-56-14943.
No. 1 publication.

The nylon 46 resin used in the present invention is
It is desirable that the intrinsic viscosity measured with m-cresol at 35 ° C. is in the range of 0.80 to 1.90, and more preferably 0.90 to 1.50.

Nylon 46 with an intrinsic viscosity of more than 1.90
The use of is not preferable because not only the fluidity at the time of molding is poor, the gloss of the appearance of the obtained molded product is lost, but also the dispersion of the mechanical properties and thermal properties becomes large. On the other hand, if the intrinsic viscosity is lower than 0.80, the mechanical strength of the molded product will be reduced.

The silicate powdery inorganic filler as the component (B) used in the present invention includes calcined kaolin, talc,
Examples thereof include wollastonite and mica. Among them, calcined kaolin and talc are preferable. Further, it is preferable that these powdery fillers are surface-treated with a coupling agent mainly containing a silane compound such as aminosilane.

[0012] The compounding amount of the silicate type powdery filler is from 6 to
It is 60% by weight, preferably 10 to 50% by weight. If the blending amount is less than 6% by weight, mechanical properties such as mechanical strength and elastic modulus are poor. On the other hand, if it exceeds 60% by weight, the fluidity of the composition in the molten state is remarkably inferior, the appearance of the resulting molded article is inferior, and the mechanical strength is reduced.

The (C) ultra high molecular weight polyethylene (hereinafter abbreviated as UHPE) used in the present invention is a homopolymer of ethylene or a small amount of other α-olefin such as propylene, 1-butene, 1-hexene, It is a copolymer with 1-octene, 4-methyl-1-pentene, etc., and has an intrinsic viscosity [η] of 10d in a decalin solvent at 135 ° C.
It is in the range of 1 / g or more, preferably 15 to 30 dl / g. When [η] is less than 10 dl / g, the molecular weight is insufficient and the effect of improving wear resistance is small.

The ultrahigh molecular weight polyethylene powder used in the present invention has a specific particle size and shape. That is,
Its particle size is such that substantially all of it passes through a 100-mesh screen and at least 20% by weight, preferably 50% by weight or more, through a 350-mesh screen, and an average particle size of 80 μm or less, preferably 3 to 60 μm, more preferably It is in the range of 3 to 40 μm. If a powder having a large particle size that remains on the 100-mesh screen exists, even if the powder is melt-kneaded with the nylon 46 resin (A), the powder has a large particle size and a large sea-island structure, resulting in a poor dispersion state.
It is not preferable because it is inferior in impact resistance and mechanical properties.

The ultra high molecular weight polyethylene powder used in the present invention has at least 2 components that pass through a 350 mesh sieve.
Since it is 0% by weight or more and the average particle size is within the above range, a composition having good dispersibility in nylon 46 resin (A) and excellent in abrasion resistance, impact resistance and mechanical properties can be obtained. . When the average particle size exceeds 80 μm, the dispersibility is poor and the above properties are not improved. On the other hand, the lower limit of the average particle size is not particularly limited, but with a fine powder having a particle size of less than 3 μm, it is difficult to handle the powder because the bulk specific gravity is low, and it is difficult to uniformly mix it with the nylon 46 resin (A). There is a case.

The shape of the ultra high molecular weight polyethylene powder (C) used in the present invention is not particularly limited, and it may be spherical, oblate spherical,
Alternatively, any shape such as a fan-shaped shape in which small balls are associated can be used.

When at least one polar group consisting of an acid, an ester, an amide, an acid anhydride, and an epoxide group is introduced into the ultrahigh molecular weight polyethylene powder used in the present invention or a part thereof and modified. , Nylon 46 resin (A) has improved affinity and mechanical properties are further improved, which is preferable. As a method for introducing the polar group, for example, a modification method in which a graft monomer having a polar group is graft-copolymerized with the ultrahigh molecular weight polyethylene powder can be adopted.

The ultra high molecular weight polyethylene powder used in the present invention is preferably 4 to 10% by weight. If the blending amount is less than 4% by weight, the abrasion resistance is not sufficiently improved, and further 10
If the content exceeds 5% by weight, the melt fluidity decreases, injection molding becomes difficult, and the original characteristics of the nylon 46 resin (A) are greatly impaired.

A pigment or other compounding agent may be added to the resin composition of the present invention in an expression amount, if necessary. Such compounding agents include fillers other than silicate powder fillers, such as glass fibers, aramid fibers, carbon fibers, steel fibers, ceramic fibers, potassium titanate whiskers, fibrous substances such as boron whiskers, carbonic acid. calcium,
Examples include powdery, granular, or plate-like inorganic fillers such as barium sulfate, glass beads, and glass flakes.

These fillers are usually blended as a reinforcing material, a surface modifier, or for the purpose of modifying electrical and thermal characteristics, etc. It should be blended within a range that does not lose the excellent properties inherent to the product and the advantages in molding.

Further, for the purpose of improving the heat resistance, an antioxidant or a heat stabilizer such as a copper compound such as copper iodide, a hindered phenol compound, an aromatic amine compound, an organic phosphorus compound or a sulfur compound may be added. . Various epoxy compounds, oxazoline compounds and the like may be added for the purpose of improving melt viscosity stability and hydrolysis resistance. As the epoxy compound, for example, bisphenol-
Bisphenol-A type epoxy compound obtained by reacting A with epichlorohydrin, aliphatic glycidyl ether obtained from reaction of various glycols or glycerol with epichlorohydrin, novolac type epoxy compound,
Aromatic or aliphatic carboxylic acid type epoxy compounds, alicyclic compound type epoxy compounds and the like are preferable, and as the oxazoline compound, aromatic or aliphatic bisoxazoline,
Especially 2,2'-bis (2-oxazoline), 2,2'-
m-Phenylenebis (2-oxazoline) is preferred.

Other stabilizers, colorants, lubricants, UV absorbers and antistatic agents can also be added.

Furthermore, other thermoplastic resins such as other polyamide resins, polyester resins, polyphenylene sulfide resins, polyphenylene ether resins, polycarbonate resins, phenoxy resins, polystyrene and their copolymers, acrylic resins and acrylics in small proportions. You may mix | blend type | system | group copolymer, polyamide elastomer, polyester elastomer, and thermosetting resin, for example, phenol resin, melamine resin, unsaturated polyester resin, silicone resin etc.

Known compounding methods can be used to obtain the resin composition of the present invention.

Usually, it is preferable to disperse these compounding components more uniformly, and a method of mixing all or a part of them simultaneously or separately with a mixer such as a blender, a kneader, a roll or an extruder to homogenize them, or It is possible to use a method in which a part of the mixing portion is mixed simultaneously or separately with, for example, a blender, a kneader, a roll, an extruder, etc., and the remaining components are mixed with these mixers or an extruder to homogenize. Further, there is a method in which a composition dry-blended in advance is melt-kneaded by a heated extruder to homogenize it, then extruded into a wire shape, and then cut into a desired length and granulated.

The molding composition produced in this way is
Usually, it is kept in a sufficiently dried state and put into a hopper of a molding machine and used for molding such as injection molding. Further, it is also possible to dry-blend the constituent raw materials of the composition and directly put them in the hopper of the molding machine and melt-knead them in the molding machine.

[0027]

EXAMPLES The present invention will be described in detail below with reference to examples.

Nylon 46 resin (STANYL, manufactured by DSM, Netherlands), calcined kaolin (Translink 44
5, manufactured by Engelhard Co., Ltd., an ultrahigh molecular weight polyethylene having a number average molecular weight of about 2 million (Miperon XM-220, manufactured by Mitsui Petrochemical Industry Co., Ltd.) with a composition shown in Table 1 and a twin screw extruder with a vent (manufactured by Japan Steel Works). , TEX44) 280-310
Extruded at ℃, to obtain pellets. Prior to compounding, all polyamides were dried at 110 ° C. under a reduced pressure of 10 Torr for 8 hours or more to have a water content of 0.1% or less.

The molding conditions, the shape of the molded article, and various properties in the examples were measured according to the following methods. (1) Molding conditions Molding machine: Toshiba IS75E Cylinder temperature: 280-300 ° C Mold temperature: 120 ° C (2) Mechanical properties Tensile strength: Compliant with ASTM D638. Bending test: According to ASTM D790. (3) Sliding test According to JIS K 7218 (a) method, against aluminum material (1050) Specific wear amount and dynamic friction coefficient are sliding conditions v = 15cm / sec, p
= 40kgf, t = 1800sec.

[0030]

[Table 1]

[Comparative Examples 1 to 4 and Examples 1 and 2] Comparative Examples 1 and 2 are examples in which calcined kaolin is added to nylon 46 resin, but the aggressiveness to aluminum during sliding is high. High, large amount of specific wear.

Comparative Examples 3 and 4 are examples in which calcined kaolin was added to nylon 46 resin, and ultra-high molecular weight polyethylene powder was added, but the amount of ultra-high molecular weight polyethylene powder was not sufficient and sliding Highly aggressive to aluminum.

Examples 1 and 2 are examples of polyamide resin compositions having significantly reduced aggressiveness to aluminum and extremely low aggressiveness to soft non-ferrous metals.

[0034]

Industrial Applicability According to the present invention, it is possible to obtain a polyamide resin having extremely excellent sliding characteristics, which does not cause a large amount of wear to a soft non-ferrous metal during sliding.

Claims (1)

[Claims] 1. (A) Nylon 46 resin 30 to 90% by weight,
A polyamide resin composition comprising (B) 6 to 60% by weight of a silicate powdered inorganic filler and (C) 4 to 10% by weight of an ultrahigh molecular weight polyethylene resin powder. However, ultra-high molecular weight polyethylene powder means that the intrinsic viscosity [η] measured in a decalin solvent at 135 ° C. is 10 dl / g or more, substantially all of the 100-mesh sieve passes, and the 350-mesh sieve has at least 20 weight. %, And the average particle size is 80 μm or less.