JPS59176340A - Ultra-high-molecular-weight polyethylene resin composition having improved resistance to impact and wear - Google Patents

Abstract

PURPOSE:To provide the titled resin compsn. which gives moldings having a coefficient of static friction approximately equal to that of ultra-high-molecular- weight polyethylene homopolymer molding and excellent resistance to impact and wear, by blending an org. peroxide and vulcanized rubber powder in specified quantities. CONSTITUTION:0.004-0.2pts.wt. org. peroxide (A) having a half life temp. of 10hr at 90-135 deg.C, such as dicumyl peroxide, and 3-100pts.wt. vulcanized rubber powder (B), (e.g. powder having a particle size of 1mm. or below formed when rubber goods such as tire or belt are grinded) are blended with 100pts.wt. ultra- high-molecular-weight polyethylene powder (C) (viscosity-average MW: 1,000,000 or above, light scattering average MW: 3,000,000 or above).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to ultra-high molecular weight polyethylene resin compositions that have improved impact and wear properties.

Conventionally, 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 been used to produce ultra-high molecular weight polyethylene (with an average molecular weight of up to about 30,000 by the viscosity method and about 30,000 by the light scattering method). 600,000), it has excellent properties such as friction and wear resistance, low temperature properties, impact resistance, and resistance to stress and cranking.
Main uses include bearings, gears, rollers, guide rails, etc. that require self-lubricating properties, low friction coefficients, and friction and wear resistance, and non-adhesive, low friction coefficients that prevent bridging and wear resistance. It was useful for lining hoppers, chutes, etc., as required, but because of its relatively low impact abrasion resistance, large-diameter particles (gravel, ready-mixed concrete, etc.)
It has had the disadvantage of severe abrasion when used as linings for areas where objects fall. Conventionally, elastic materials such as polyurethane and rubber have been used for applications that require impact and abrasion resistance as described above. However, in this case, the coefficient of friction was the same. Therefore, the present inventors set out to obtain an ultra-high molecular weight polyethylene resin composition that had a static friction coefficient comparable to that of a molded ultra-high molecular weight polyethylene resin alone and had excellent impact and wear resistance properties. As a result of intensive study on the objective, the objective was achieved by blending vulcanized rubber powder and I-1 peroxide with ultra-high molecular weight polyethylene.

Specifically, the present invention is characterized by adding 0.004 to 0.00 parts by weight of organic peroxide to 100 parts by weight of ultra-high molecular weight polyethylene.
2 parts by weight and vulcanized comb powder.

The ultra-high molecular weight polyethylene used in the present invention refers to commercially available powdered ultra-high molecular weight polyethylene, which has an average molecular weight of 1 as determined by the viscosity method.
1,000,000 or more, or 3,000,000 or more by light scattering method.

In addition, the organic peroxide referred to in the present invention refers to dicumyl peroxide, dialkyl peroxide such as 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 1,1-bis (t-butylperoxy) 3.3.
A general term for organic peroxides, such as peroxyketals such as 5-trimethylcyclohexane, which have a 10-hour half-life temperature of 90'C to 135C and are commonly used for crosslinking polyethylene. These are preferably in powder form in consideration of dispersion in the ultra-high molecular weight polyethylene powder.

The amount of organic peroxide added is 0.004 to 0.2 parts by weight, preferably 0.02 to 0.2 parts by weight, per 100 parts by weight of the ultra-high molecular weight polyethylene powder.

If it is less than 0.004 parts by weight, the improvement in wear resistance will be small;
．． It is known that when the amount is 2 parts by weight or more, the coefficient of dynamic friction increases.

Further, the vulcanized rubber powder as used in the present invention refers to vulcanized rubber powder with a particle size of about 1 sushi or less, such as rubber powder generated when polishing rubber products such as tires and healds. The blending amount of the vulcanized rubber powder is determined from the value of the static friction coefficient shown in the figure.
3 to 100 parts by weight is preferred.

Moreover, the ultra-high molecular weight polyethylene resin composition of the present invention is
It goes without saying that in addition to the above-mentioned additives, reinforcing agents, extenders, additives, etc. that are commonly mixed into resins may also be included.

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 [manufactured by Hoechst, 11o
To stalen GUR412, dicumyl peroxide diluted to 40% with calcium carbonate [NOF 0 grade, Percmill D-401, and tire polishing rubber powder were added to Henschel Miki No. 1 at the mixing ratios shown in Table 1. The mixture was mixed for 20 minutes at 800 rpm to obtain a powdered ultra-high molecular weight polyethylene resin composition. This powdered ultra-high molecular weight polyethylene resin composition is prescribed! (370g>
Weighing and temporary production mold (inner surface 180nva x 22f)
+nm) using a 37 ton press (80-100
After compression with 10 molecules (kg/c), set the press heating plate to 230℃, apply a surface pressure of 20 to 40 kg/cffl and heat for 65 minutes, then 80 to 100 kg/cn.
Apply lO surface pressure and cool for 30 minutes, thickness 10m+nX1W1
Form a slope of 78 mm x 218 m + n, and from this slope 1
A slope measuring 00+nm x 220+Rm was cut out and used as a test piece for static friction coefficient and impact wear. The coefficient of static friction was determined by placing an iron piece (contact area 18 cJ, weight ff 1123 g) on a sample plate and measuring the angle of inclination of the sample plate when the iron piece began to slide.

If this angle of inclination is θ, then tanθ is the coefficient of static friction. The results are shown in the figure.

Next, for the impact abrasion test, each test piece was pasted inside the hot spring for fresh concrete for 1 month, 1.5 months after the start of the test.
Changes in wear were visually confirmed for 2 months and every month thereafter. In addition, the amount of fresh concrete input is 1 hatch 1.5
M is approximately 380 pa-noti/day, the particle size of the gravel contained is 0.15 to 40 mm, and the falling height is 850 mm. In addition, the approximate mixing ratio of ready-mixed concrete 1- is sand (
Particle size 0.15~5III): Gravel (particle size 5~
40 mm): cement: water - 5:1:1:2. The test results are shown in Table 2.

(Hereafter, blank space) Table 1 (parts by weight) (Note) The number in parentheses in the organic peroxide blending ratio shows the value converted to the effective organic peroxide ratio.

As is clear from the results shown in Table 2, the composition of the present invention has superior impact and wear resistance properties compared to the molded product made from ultra-high molecular weight polyethylene alone (Comparative Example 1). Furthermore, as can be seen from the figure, in a compounded composition in which the tire polishing rubber powder is 10 parts by weight or less per 100 parts by weight of ultra-high molecular weight polyethylene, the coefficient of static friction is the same as or lower than that of a molded product of ultra-high molecular weight polyethylene alone. It is fully applicable.

[Brief explanation of the drawing]

The figure relates to an example of the present invention and is a graph showing the relationship between the amount of tire polishing rubber powder added and the coefficient of static friction. Patent applicant San-Seven Star Belt Co., Ltd.

Claims (1)

[Claims] 0.004 to 0.2 parts by weight of organic peroxide and vulcanized rubber powder are blended with 100 parts by weight of ultra-high molecular weight polyethylene powder with an average molecular weight of 1 million or more by a viscosity method and an average molecular weight of 3 million or more by a light scattering method. An ultra-high molecular weight polyethylene resin composition that improves impact and wear resistance characteristics.