Polyplastics Co., Ltd.

Hoechst Aktiengesellschaft

Toshiro Murao

Kaoru Yamamoto

Dietrich Fleischer

Yoshiharu Suzuki

Gerhard Reuschel

Hiroaki Konuma

Keiichi Kanaka

Mitsuo Wada

Makoto Kamiya

Mitsuharu Kusagaya

Nagayoshi Maeda

Michiaki Ogura

A process for efficiently producing a hollow molding or a sheet- or rod-shaped molding includes subjecting a composition containing a polyoxymethylene copolymer resin having substantially a linear molecular structure and a melt flow index (MI) value (190.degree. C., 2160 g load) of 0.1 to 2.0 g/10 min to blow -molding or extrusion-molding operations. The preferred polyoxymethylene copolymer is prepared by copolymerizing trioxane as the principle monomer with a cyclic ether or cyclic formal comonomer in the presence of 1.times.10.sup.-3 to 1.times.10.sup.-2 molar % of a boron trifluoride catalyst or a coordination compound thereof, while regulating the chain-terminating or chain-transferring impurities in the reaction system to 1.times.10.sup.-2 molar % or less, and then cooling the product obtained to a temperature of 45.degree. or below within 30 seconds so as to deactivate the catalyst.

Method of blow or extrusion molding polyoxymethylene resin

Processes for producing a polyoxymethylene copolymer includes forming a crude polyoxymethylene copolymer by subjecting a reaction system containing trioxane, a cyclic ether or cyclic formal comonomer, and a catalyst (e.g., boron trifluoride or a coordination compound thereof) to copolymerization reaction conditions. During copolymerization, both the total content of impurities and catalyst in the copolymerization reaction system are adjusted. In this regard, the impurities content (i.e., those compounds which form unstable end groups in the polyoxymethylene copolymer and/or those compounds having a chain-terminating or chain-transfer function) in the copolymerization reaction system is adjusted to 1.times.10.sup.-2 mole percent or less based on the total monomer amount, while the the content of the catalyst in the copolymerization reaction system to between 1.times.10.sup.-3 to 1.times.10.sup.-2 mole percent based on the total monomer amount. Immediately after copolymerization has been completed, the crude polyoxymethylene copolymer is quenched to a temperature of 45.degree. C. or less within 30 seconds after completion of copolymerization. Quenching of the crude polyoxymethylene copolymer is preferably simultaneously accompanied by deactivation of the catalyst by bringing the crude polyoxymethylene copolymer immediately following completion of copolymerization into contact with a cold liquid which contains a catalyst deactivator.

Process for producing polyoxymethylene copolymer having reduced amount

Novel moldable, highly stable, normally solid polyoxymethylene resin compositions and molded articles formed of the same include a stabilizing effective amount of an alkoxy-substituted phenoxy-containing compound having the formula (I) or (II):

Stabilized polyoxymethylene molding compositions and molded articles

Provided herein is a process for surface treatment of moldings of liquid-crystalline polyester resin which comprises roughening with an alkaline aqueous solution the surface of moldings of melt-processable polyester capable of forming an anisotropic molten phase. The roughened moldings are activated by contacting with an aqueous solution of an ampholytic surface active agent such as an aminocarboxylate. The process is intended to provide the moldings with surface characteristics suitable for surface decoration such as printing, painting, metallizing, and plating and also for bonding with an adhesive.

Process for surface treatment of moldings of liquid-crystalline

Three dimensional molded articles comprising liquid crystalline polyesters are recognized to be extremely difficult to finish such as by printing, painting, metallizing, plating, etc. An effective answer to this difficulty is provided by initially blending within the liquid crystalline polyester at least one particulate inorganic filler selected from the group consisting of Group II elements of the periodic table and oxides, sulfates, phosphates, silicates, and carbonates thereof, and elements of aluminum, silicon, tin, lead, antimony, and bismuth and oxides thereof, in an amount of 5 to 80 percent by weight; forming a molded article from the same; and contacting the resulting molded article with an acidic solution containing at least 80 percent by weight of sulfuric acid. The requisite surface modification for finishing to form a quality product is made possible.

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Shizuoka, Japan

Toshiro Murao