Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Patent
1996-12-12
1998-12-22
Cain, Edward J.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
525399, 525400, C08L 6102
Patent
active
058521356
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to a resin composition comprising a modified polyacetal, which has improved affinities for polymers and is useful for obtaining a polymer alloy, and to a method of producing the resin composition.
BACKGROUND TECHNOLOGY
A polyacetal has excellent mechanical strength, slidability, heat resistance, chemical resistance, moldability (formability) and electrical characteristics (electrical properties), and hence is generally employed as an engineering plastic in various fields. Such polyacetal is, however, not always satisfactory in acid resistance, adhesion (adhesive properties), painting quality, printing quality, dye affinity, weather resistance or other properties.
Therefore, such compositions have been expected as produced by alloying the polyacetal with other thermo-plastic resin for supplying disadvantages of the polyacetal and for imparting the excellent characteristics of the polyacetal to the counter resin of the alloying and hence to effectively exhibit advantages of the both resins. The polyacetal is, however, extremely poor in affinities and compatibilities (miscibilities) with respect to other materials. Accordingly, when the polyacetal is blended with other thermoplastic resin, the characteristics of the both resins do not exhibit with validity, and the resultant composition only provides remarkably low weld strength and weld elongation. In particular, such significantly low weld strength and weld elongation seriously interfere with commercial production of an alloy of the polyacetal and other thermoplastic resin.
For the purpose of improving affinities of the polyacetal, it is effective to introduce an adequate modifying group into the polyacetal for modification, and various technologies for modification of the polyacetal Japanese Patent Publication No. 23467/1968 (JP-B-43-23467), Japanese Patent Publication No. 19425/1972 (JP-B-47-19425), Japanese Patent Application Laid-open No. 21618/1991 (JP-A-3-21618), Japanese Patent Application Laid-open No. 21619/1991 (JP-A-3-21619), etc.!.
These technologies, however, are technologies in which a modifying group is directly introduced into a polyacetal in polymerization step by copolymerizing formaldehyde or trioxane with a comonomer having a variety of a modifying group as a substituent (e.g. a cyclic ether or cyclic acetal each having aminoaldehyde, a nitro group, a nitrile group, a carboxyl group or an amide group). Therefore, according to these technologies, polymerization reactivity is sacrificed and hence a copolymer with a high molecular weight can not be obtained in a high yield.
Further, a process for producing a reinforcing agent-containing resin composition which comprises adding a reactive compound having a variety of modifying group to a polyacetal resin as produced previously by polymerization, and melting and kneading the resultant mixture in the presence of a filler and a free-radical initiator has been proposed, for the purpose of enhancing reinforcing effects by means of the reinforcing Japanese Patent Publication No 6969/1985 (JP-B-60-6969)!.
According to these technologies, however, introduction efficiency of the modifying group is extremely low and the polyacetal is decomposed and degraded in melting and kneading step, and hence these technologies will not be effective modifying processes. Moreover, resultant compositions obtained by these technologies beforehand contain specific reinforcing agents so that they can not be applied to various polymer alloys in a broad range which comprise two or more species of resins being immiscible (incompatible) with each other, and hence the resin composition needs to be prepared for every application, respectively. In particular, when two or more species of thermoplastic resins immiscible (incompatible) with each other are employed, they are hardly molten and mixed homogeneously, so that homogeneous modification and polymer alloying can not be expected according to the above mentioned technologies.
Moreover, when the free-radical initiator and the polyac
REFERENCES:
patent: 5183860 (1993-02-01), Kashihara
Kanai Hiroyuki
Matsushima Mitsunori
Serizawa Hajime
Cain Edward J.
Polyplastics Co. Ltd.
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