Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Patent
1997-09-24
1998-12-29
Short, Patricia A.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
524230, 524243, 524268, 524315, 524318, 524512, 525 64, 525101, 525154, 525405, C08L 5900
Patent
active
058543244
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a polyacetal resin composition having excellent friction resistance and abrasion resistance performances by improving the compatibility, dispersibility and interfacial adhesiveness between resins, which is obtained by blending a polyacetal resin with a specific olefinic polymer and an alkylene glycol polymer having a primary or secondary amino group optionally together with, further, a lubricant if required, and melting and kneading.
Polyacetal resins have widely been used in some fields such as automobiles, and electrical and electronic appliances since they have well-balanced mechanical properties, and are excellent in, e.g., friction resistance and abrasion resistance performances, chemical resistance, heat resistance and electrical characteristics. However, the performances required in such fields are gradually escalating, and, as one example, there has been desired to further improve the sliding performances, as well as general physical properties. Although such sliding performances include, of course, the friction coefficient and the specific abrasiveness, the sliding performances under a high surface pressure have particularly been considered as important ones.
Generally, addition of a fluororesin or a polyolefinic resin, or addition of a lubricant such as fatty acids, fatty acid esters, silicones and various mineral oils, to polyacetal resins is effected for the purpose of the improvement of the sliding performances.
The addition of a fluororesin or a polyolefinic resin improves the sliding performances to a certain extent. However, since these resins exhibit poor compatibility with polyacetal resins, the resin compositions obtained have unsatisfactory sliding performances under a high surface pressure, and they are liable to cause peeling on the surfaces of molded articles or to form a deposition on a mold.
While, the addition of a lubricant has various disadvantages such as the trouble of the processing in extrusion or molding, or the bleeding during using.
Thus, known conventional methods are not enough from the view points of the sliding performances, molding processability and other practical behaviors, and materials improved in such various properties have been desired.
The present inventors have extensively investigated to attain the above object, and, as a result, have found that a resin composition having excellent sliding performances as well as excellent general physical properties and surfaces of molded articles can be obtained by blending a polyacetal resin with a modified olefinic polymer modified with at least one member selected from the group consisting of an unsaturated carboxylic acid and an acid anhydride thereof, and their derivatives, and an alkylene glycol polymer having a primary or secondary amino group(s) and having a specific molecular weight, and melting and kneading them, since the dispersability between resin components is remarkably improved, thus completed the present invention.
Thus, the present invention provides a polyacetal resin composition prepared by melting a polyacetal resin (A), a modified olefinic polymer (B) modified with at least one member selected from the group consisting of an unsaturated carboxylic acid and an acid anhydride thereof, and their derivatives, and an alkylene glycol polymer (C) having a primary or secondary amino group(s) and having a number-average molecular weight of 400 to 500,000, and kneading them each other, wherein component (B) is contained in an amount of 1 to 100 parts by weight based on 100 parts by weight of component (A), and component (C) is contained in an amount of 0.1 to 100% by weight based on component (B); and a slide member comprising such the polyacetal resin composition.
Now, the present invention will be explained in detail.
The polyacetal resin (A) used in the present invention may be any of a polyoxymethylene homopolymer which is a polymer having, as the main constitution unit, an oxymethylene group (--CH.sub.2 O--); and a copolymer, terpolymer or block copolymer having, as the
REFERENCES:
patent: 5344875 (1994-09-01), Niino
patent: 5346737 (1994-09-01), Takahashi
patent: 5559180 (1996-09-01), Takahashi
Sano Hiroyuki
Tajima Yoshihisa
Takayama Katsunori
Polyplastics Co. Ltd.
Short Patricia A.
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