JPS6140346A - Ultra-high-molecular weight polyethylene resin composition having antistatic activity - Google Patents

Abstract

PURPOSE:To provide the titled composition having low charge generation by friction, etc. independent of the environmental conditions, having excellent appearance, and suitable as a sliding part to be kept from electrostatic charge, by mixing specific amounts of an electrically conductive metal oxide and an antistatic agent to a polyethylene resin. CONSTITUTION:The objective composition can be prepared by compounding (A) 100pts.(wt.) of an ultra-high-molecular weight polyethylene powder having an average molecular weight of >=1,000,000 by viscosity method and >=3,000,000 by light-scattering method with (B) 3-30pts., preferably 5-10pts. of an electrically conductive metal oxide powder [e.g. titanium oxide (IV) modified with niobium oxide (V), etc.] and (C) 0.1-5pts., preferably 0.2-3pts. of an antistatic agent (e.g. liquid or powdery nonionic surfactant).

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to an ultra-high molecular weight polyethylene resin composition having an antistatic function. <(This article also relates to an ultra-high molecular weight polyethylene resin composition that has a good appearance and provides an antistatic function suitable for use mainly in sliding parts that dislike static electricity.

(Prior art) Ultra-high molecular weight polyethylene, which has an average molecular weight of 1 million or more by the viscosity method and 3 million or more by the light scattering method, has excellent wear resistance,
It has characteristics such as excellent impact resistance and low coefficient of friction.

For this reason, lining materials for hoppers, chutes, etc.
It is used for bearings, gears, rollers, guide rails, etc., but because it has a high electrical resistance and is easily charged, there is a high risk of attracting dust, etc. To solve this,
Filling with carbon black, metal powder, etc. was considered, but
These methods have problems such as unsightly appearance and contamination or damage to the friction partner material, which limits the scope of their use. In addition, a method of using an ordinary kneaded-in type or surface-applied type antistatic agent has been proposed, but in this case, the effect is lost due to friction on the resin surface and washing with water, and it is also affected by the operating temperature and temperature/humidity. This caused problems such as large fluctuations in effectiveness.

, (Problems to be Solved by the Invention) The present invention improves these points, and has a structure that has less electrification due to friction, etc., has electrical characteristics that are not affected by friction, water washing, etc., and has a more beautiful appearance. An ultra-high molecular weight polyethylene resin composition is provided.

(Means for solving the problem) That is, the feature of the present invention is that ultra-high molecular weight polyethylene powder having an average molecular weight of 1 million or more according to the viscosity method and 3 million or more according to the light scattering method, The present invention is an ultra-high molecular weight polyethylene resin composition having an antistatic function, containing a metal oxide and a liquid or powder antistatic agent.

The conductive metal oxides mentioned here include titanium oxide (■) modified with niobium (V) oxide, zinc oxide modified with aluminum oxide, and tin oxide modified with antimony oxide, which are electrically conductive or semiconducting. The compounding amount is 3 to 30 parts by weight, preferably 5 to 10 parts by weight, per 100 parts by weight of ultra-high molecular weight polyethylene powder.

If it is more than 30 parts by weight, the mechanical properties such as impact strength and quality will be deteriorated, and if it is less than 3 parts by weight, the desired antistatic function cannot be obtained particularly under low humidity or after friction washing.

Furthermore, the antistatic agent referred to here is a liquid or powdered nonionic surfactant that is generally kneaded into polyolefin resin, and its amount is based on 100 parts by weight of ultra-high molecular weight polyethylene powder. The amount is 1 to 5 parts by weight, preferably 2 to 3 parts by weight. If it is more than 5 parts by weight, the antistatic agent will migrate to the resin surface and cause a bleed phenomenon, which tends to cause stickiness, and the improvement in electrical properties will be reduced. On the other hand, if it is less than 1 part by weight, the electrical properties will not be sufficiently improved.

The present invention imparts an antistatic function to an ultra-high molecular weight polyethylene resin by filling it with a conductive metal oxide and an antistatic agent as described above, but it also improves the appearance by adding a pigment, etc. to this composition. In particular, it is possible to improve the abrasion resistance by crosslinking with organic peroxides, and to impart various properties by adding other fillers.

Furthermore, when molding this powdered ultra-high molecular weight polyethylene resin composition, it can be molded into plates, rods, pipes, and irregularly shaped products by compression molding, ram extrusion molding, injection molding, etc. in the same way as the usual molding methods for ultra-high molecular weight polyethylene powder. etc. can be manufactured.

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 to these examples.

(Example) Ultra-high molecular weight polyethylene powder [Hoechst Ho5t]
alen G U R412] and aluminum oxide modified zinc oxide [manufactured by Honjo Chemi A-RU] as a conductive metal oxide.
conductive zinc white] or niobium oxide-modified titanium oxide [Neocon NO, 8 White, manufactured by Dainichiseika Chemical Industry Co., Ltd.], liquid antistatic agent [Electro Stripper EA manufactured by Kao Soap@], or powdered antistatic agent [Flower]. Electro Stripper TS-21 manufactured by Oiseki 111a■ was added at the mixing ratio shown in Table 1, and mixed for 15 minutes at 80 rpm in a Henschel mixer. Next, 80g of this blended powder was weighed out, and a temporary mold (inner surface 12
5mm x 210mm) and press to 100kg.
f/ csA x 5 molecules After compression, press the hot plate at 23
Set at 0℃, heated for 45 minutes with a surface pressure of 40kgf/el11, and further cooled for 30 minutes with a surface pressure of 100kgf/laa to form a plate with a thickness of 3mm.
A test piece for measuring electrical properties was prepared, measuring m×100 mm in length.

Further, 350 g of the above blended powder was weighed out and molded into a 13 mm thick plate using the same method as for the 3 mm plate (however, the heating time was 80 minutes), from which an Izod impact test piece was prepared.

As for electrical properties, surface resistance and charging voltage were measured. The surface resistance was measured using the above test piece at 20°C, humidity 6.
Yokogawa Hurent Paso Card @43 under 5% atmosphere
298 HIGHRESISTANCBMETER and 160088 RESISTIVITY C1l! Ll,
Measured using. The charging voltage was determined by rubbing the test piece with a paper towel 20 times in an atmosphere of 20°C and 65% humidity, and the value after 10 seconds was calculated as 5HISH100&CO,,L.
Measurement was performed using 5TATIRON TYPE-3 manufactured by TD.

The impact strength is 1 width from the above 13mm thick plate.
A test piece of 2.7mm x thickness 12.7mm x length 63.5mm with a notch depth of 2.54mm was machined, and the test piece was 92.0mm thick.
Measurement was performed according to JIS K7110 using a gf/cm hammer. These results are shown in Table 2.

Table 1 (2) Quantity Table 2 From Tables and 2, the compositions of the present invention (Examples 1 to 5) have relatively low surface resistance and charging voltage, and the test pieces did not break in the Izot impact test and were resistant to impact. I know it's strong.

In contrast, those containing no antistatic agent (Comparative Examples 1 to
It can be seen that in case 3), the charging voltage is high and charging is easy. In order to solve this problem, when the amount of conductive metal oxide blended is increased (Comparative Example 4), the impact strength decreases. Furthermore, when only an antistatic agent is added (Comparative Examples 5.6), the surface resistance and charging voltage after washing with water increase significantly, and there is a problem in the durability of the antistatic effect. Furthermore, with this formulation, it is expected that the charging voltage will be high under low humidity conditions.

(Effects of the Invention) As described above, the composition of the present invention contains both a conductive metal oxide and an antistatic agent, so that it is less likely to be charged by friction, etc., and this property does not change easily when washed with water.
It also has high impact strength. In addition, it has a beautiful appearance because it is white to light gray and can be easily colored, and it can be said that it is particularly suitable for applications in sliding parts that are sensitive to static electricity.

Claims (1)

[Claims] 1. Ultra-high molecular weight polyethylene powder having an average molecular weight of 1 million or more by the viscosity method and 3 million or more by the light scattering method, mixed with a powdery conductive metal oxide and liquid or powder. An ultra-high molecular weight polyethylene resin composition having an antistatic function, characterized in that it contains an antistatic agent. 2. The charging according to claim 1, wherein 3 to 30 parts by weight of a conductive metal oxide powder and 0.1 to 5 parts by weight of an antistatic agent are blended with 100 parts by weight of the ultra-high molecular weight polyethylene powder. Ultra-high molecular weight polyethylene resin composition with preventive function.