JPS63175069A - Additive for improving low frictional properties of synthetic resin - Google Patents

Abstract

PURPOSE:To provide the titled additive capable of improving the low frictional properties of molded articles when incorporated in synthetic resins such as polyamide, also of giving molded articles of good appearance, consisting of ultra-high molecular weight polyethylene and a polyethylene with a specified range of intrinsic viscosity. CONSTITUTION:The objective additive consisting of (A) an ultra-high molecular weight polyethylene component with an intrinsic viscosity determined at 135 deg.C in the form of decalin solution (hereafter referring to 'intrinsic viscosity') >=6(pref. 6-40)dl/g, MFR pref. <=0.01g/10min, density >=0.92g/cm<3> and melting point >=115 deg.C and (B) a polyethylene component with an intrinsic viscosity 0.1-5(pref. 0.3-4)dl/g, density pref. 0.92-0.97g/cm<3> and melting point 115-145 deg.C with the weight ratio A/B=90-10/10-90 (pref. 85-15/15-85) and at least part of the component A and/or B modified with polar group.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an additive for improving the low friction properties of synthetic resins such as polyamides, polyacetals, polyesters and polycarbonates.

[Conventional technology]

Synthetic resins such as polyamide, polyacetal, polyester, and polycarbonate have excellent mechanical strength and abrasion resistance, and are used for machine parts such as bearings and gear parts by injection molding. However, compared to metal materials such as brass and copper, the limit pv value (bearing material has a constant load CP)
This is the limit value of the load at which the material will melt or seize if it exceeds the speed (V). ) is low. For this reason, it has been proposed to add high-density polyethylene powder to these synthetic resins to improve their low friction properties, thereby making them suitable as materials for bearings and the like. (Special public show 'IA-'I/da5
No. 6) According to this method, when ultra-high molecular weight polyethylene powder is added to a synthetic resin, low friction properties are improved, but the appearance of the molded product is often impaired.

This tendency is particularly strong when the particle size of the powder is large. Therefore, the applicant proposes to use a powder with a specific particle size distribution. (JP-A-1.0-/4t'1J
(No. j1) As a result, it cannot be said that the external appearance of molded products with good dispersibility is necessarily good.

On the other hand, if the molecular weight of the high-density polyethylene added is low, it may adversely affect the excellent mechanical strength of the synthetic resin that serves as the paste.

[Problem that the invention attempts to solve]

The present invention further improves the low friction properties of molded products without adversely affecting the mechanical strength and abrasion resistance of synthetic resins such as polyamide, polyacetal, polyester, and polycarbonate, and provides molded products with excellent appearance. The purpose of the present invention is to provide additives for synthetic resins that are suitable for obtaining additives for synthetic resins.

[Structure of the invention]

That is, the present invention provides an ultra-high molecular weight polyethylene component (A) having an intrinsic viscosity of tde/p or more of 90 to 10 weight 4
%, and a polyethylene component (B) having an intrinsic viscosity of [7] O0/ to 5 deAl in an amount of 10 to 10%.

Among the additives of the present invention, the intrinsic viscosity ('>);
The ultra-high molecular weight polyethylene component (A) having a molecular weight of at least p has an intrinsic viscosity ω] measured at 735 in a decalin solvent of at least 0 ty/g, preferably at least 0 y/g, more preferably from 10 to 1 y/g /i range. Such polyethylene components are also preferably melt flow ray (MFR: ASTM D/23gF) o
, o 7g710 minutes or less, density (n: AsT+1D
/sos) is O, des o g/ is one or more, the melting point (
Tm: ASTM: D 3'l/ri) is //li and above.

Such polyethylene components include homopolymers of ethylene, or ethylene and small amounts of other α-olefins, such as propylene, /-phthene, /-hexene, /~octene, goomethyl-/-pentene, etc. Copolymers containing ethylene as a main component are preferred and are crystalline resins.

Among the additives, the polyethylene component (B) has an intrinsic viscosity Q] of 0, / to sd/! measured in a decalin solvent at /3 left. /'g, preferably 0.3 to g de/g
is within the range of Such polyethylene component (B) is
Preferably, the density is θ, the water weight is θ, and the density is 077/ly.
n', preferably has a melting point in the range of /y to /y. For such polyethylene, it is preferable to use an ethylene homopolymer similar to the polyethylene component (A) or an ethylene-based copolymer consisting of ethylene and a small amount of other α-ole2yne, etc. It is a synthetic resin.

The ratio of ethylene component (A) and ethylene component (B) in the polyethylene component in the additive is (A): (B)=
90-10 10-90% by weight, preferably gs
~/Weight Section:/Yo~! r! Weight%. The component ratio is adjusted within this range depending on the application.

If the ethylene component (A) is less than 10% by weight, it will adversely affect the mechanical strength of the added synthetic resin. Furthermore, if the ethylene component (A) exceeds 90% by weight, the appearance of the molded product will not be good in many cases even if it is added to the synthetic resin.

These ethylene component (A) and/or ethylene component <B) are preferably modified by introducing a polar group into part or all of them in order to improve the affinity with the synthetic resin. Methods for introducing such polar groups include carboxylic acids, their acid halides, esters, amides, imides,
A modification method in which a graft monomer having an anhydride or an epoxy group is graft-copolymerized onto these ethylene components is preferred.

Examples of graft monomers having polar groups include acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, crotonic acid, nadic acid -2
, 3-dicarboxylic acid) or derivatives of acid halides, esters, amides, imides, anhydrides, etc., such as malenyl chloride, maleimide, acrylic amide, methacrylic amide, glycidyl methacrylate,
Examples include maleic anhydride, citraconic anhydride, monomethyl maleate, dimethyl maleate, and glycidyl maleate.

As a method for graft copolymerizing these graft monomers to the ethylene component, various conventionally known methods can be employed. For example, there is a method in which the ethylene component is suspended or dissolved in a solvent, and then the graft monomer and a radical initiator such as peroxide are added and mixed at a temperature of usually from go to io'c to carry out a graft reaction.

As a method for preparing the additive of the present invention, the polyethylene component (
There is a method in which A) and the polyethylene component (B) are prepared separately and mixed together, and a method in which multi-stage polymerization is performed during polyethylene polymerization to obtain the composition of the additive of the present invention.

The additive of the present invention is added to the synthetic resin in the form of powder, pellet, or the like. In terms of dispersibility in synthetic resins, powder form, particularly particle size 1000 to 3μ, particularly preferably 1
It is desirable to set it to 00 to 5μ. However, even in the form of pellets, the additive of the present invention has the effect of improving the low frictional resistance of synthetic resins and the appearance of molded products in a well-balanced manner.

The additives of the present invention include various stabilizers normally added to conventional polyethylene, such as heat-resistant stabilizers and weather-resistant stabilizers, as well as nucleating agents, antistatic agents,
This includes embodiments in which additives such as flame retardants, pigments, and dyes are blended.

The synthetic resins to which the additive of the present invention is blended include synthetic resins such as polyamide, polyacetal, polyester, and polycarbonate, and among them, synthetic resins called engineering plastics.

That is, polyamide contains hexamethylene diamine,
Big ethylene diamide? , dodecamethylenediamine,
aliphatic such as co, goo or co, g, ditrimethylhexamethylenediamine, eight-three or hecubis(aminomethyl)cyclohexane, bis(p-aminocyclopequinlemethane), m- or p-xylylenediamine , alicyclic and aromatic diamines and adipic acid, speric acid,
Boriaamides obtained by polycondensation with aliphatic, alicyclic, and aromatic dicarboxylic acids such as sebacic acid, cyclohexanedicarboxylic acid, terephthalic acid, and inphthalic acid; amino acids such as ε-aminocamyronic acid and //-aminoundecanoic acid; Examples include polyamides obtained by i-merization of carboxylic acids, polyamides obtained from lactams such as ε-camyrolactam and ω-laurolactam, copolyamides made of these components, and mixtures of these polyamides.

Specifically, nylon 2, nylon 66, nylon 610
1 Nylon Wa, Nylon //, Nylon/Co, Nylon 6/66, Nylon T, T, /b10゜Nylon 6//
/ etc. Among these, nylon 6 and nylon 66 are preferred because of their excellent melting point and rigidity. In addition, the molecular weight is not particularly limited5, but the relative viscosity is usually r (JXS
KAgIO.

Polyamide with a value (measured in 91% sulfuric acid) of 0.3 or more is used.
However, those with a value of 2.0 or more are preferred.

Polyacetal is also a crystalline material, which is a formaldehyde homopolymer or a copolymer of formaldehyde trimer trioxane and a small amount of ethylene oxide or a cyclic ether such as 3-dioxane, and is also called polyoxymethylene. It is a thermoplastic resin.

In addition, polyesters include aliphatic glycols such as ethylene glycol, propylene glycol, tanediol, neopentyl glycol, and hexamethylene glycol, alicyclic glycols such as cyclohexane dimetatool, and aromatic dihydroxy compounds such as bisphenol. , or a dihydroxy compound unit selected from these types or more, and terephthalic acid, inphthalic acid, 2.6-
Aromatic dicarboxylic acids such as naphthalene dicarboxylic acid, aliphatic dicarboxylic acids such as oxalic acid, succinic acid, adipic acid, sebacic acid, undecadicarboxylic acid, alicyclic dicarboxylic acids such as hexahydroterephthalic acid, or one or more of these A crystalline thermoplastic resin formed from a dicarboxylic acid unit selected from
Examples include in-7-thalate/terephthalate copolymers modified with a small amount of triol or tricarboxylic or higher polyhydroxy compounds such as tricarboxylic acid, or polycarboxylic acids.

Furthermore, polycarbonate includes polymer positional polymers synthesized from aromatic dioxy compounds (bisphenol), particularly bisphenol A, as a raw material among high molecular weight polymers having carbonate ester bonds in the molecular main chain.

The blending ratio of the additive of the present invention to the synthetic resin is generally from qg to 65% by weight of the synthetic resin, preferably from 97% to 300% by weight. Additives 2 to 3 of the present invention for A! r weight: t
%, preferably in the range 3 to 30% by weight.

When the amount of the additive of the present invention is less than 333%, there is almost no effect of improving the low friction properties of the synthetic resin. If it exceeds A, it will have an adverse effect on the melt flow characteristics of the synthetic resin.

As a method for blending additives into a synthetic resin, there is a method of melt-kneading the synthetic resin and the additives. In this case, there are no particular limitations as long as the synthetic resin and additives are kneaded at a temperature that melts them, but the resin temperature is usually -〇〇 to 3θO, preferably 200 to 270. . For kneading, a single screw extruder, a twin screw extruder, a Banbury mixer, etc. are used.

The synthetic resin composition prepared as described above may contain heat-resistant stabilizers, weather-resistant stabilizers, lubricants, nucleating agents, antistatic agents, pigments, flame retardants, inorganic or organic reinforcing materials, fillers, etc., depending on the purpose. This includes embodiments in which agents, etc. are blended.

[Function] The additive of the present invention can be added to synthetic resins such as polyamide, polyacetal, polyester, and polycarbonate to form molded products without adversely affecting the mechanical strength and abrasion resistance of these synthetic resins. It is possible to improve the low friction properties of the molded product and to make it into a molded product with excellent external appearance.

〔Example〕

Comparative Example 1-M and Examples/~ Polyacetal (trade name: Duracon M 90°, manufactured by Polyplastics ■: POM) and nylon 6 (trade name: Alamine CM-100/, manufactured by Toshi ■: NYA) were used. Also, the intrinsic viscosity ω〕(decalin, /3jυ) 2/
dt/i ultra high molecular weight polyethylene (UHMI) E)
Ultra-high molecular weight polyethylene component (h) consisting of as weight%
and equilibrium limiting viscosity I″17] (in Decalin, /Jj?)i
The additive of the present invention was used, which consisted of a polyethylene component (B) of RDTY.

A composition obtained by melting and kneading these materials was injection molded to prepare a test piece, and the physical properties were measured using the following method. Similarly, P
Physical property values were also measured for OM, NY & plain flavor.

Breaking strength: ASTM D 1.3g, however, the test piece shape was ASTM Q and the tensile speed was 50mm/m.
ix, and the tensile strength at break (TS: 1) and elongation at break (rtL: 1) were determined.

Zero impact strength (IZOD: Kp-rn/3): AST
MD 2! A. Notched, specimen thickness: 3. Two mornings.

Friction coefficient: Using a friction and wear tester model EFM-1 manufactured by Toyo Baldwin Co., Ltd., the mating material was a steel plate (5US-30 da), and the peripheral speed (V) was 0, l.
m/sea, load 7. It was calculated as zKy/1m2.

Taper wear test: JIS K AwoOko, however, the amount of wear is H-, 2, 2
The wear amount (1) g) after 10θθ rotation was determined using the following.

Limit pv value measurement test Using a friction and wear tester model EFM-1 manufactured by Toyo Baldwin Co., Ltd., the material was steel plate (5US-30g), and the peripheral speed (V) was 0.1.
m/sec constant, load (P must θ, Kg/1m2
The limit pv value (K9/1m2.m/rniyr) is determined by increasing the load in increments, and the load on the test piece begins to swell due to frictional heat.
I asked for

The results are shown in Table 1.

Claims (1)

[Claims] (1) 90 to 10% by weight of an ultra-high molecular weight polyethylene component (A) with an intrinsic viscosity [7] of 6 al/g or more; and a polyethylene component (A) with an intrinsic viscosity [7] of 0.1 to 5 dl/9.
B) An additive for improving the low friction properties of synthetic resins, characterized by comprising 10 to 90% by weight.