A process for producing a polyacetal copolymer, the process making catalyst deactivation easy and efficient. Trioxane as a major monomer is copolymerized with one or more comonomers that are a cyclic ether and/or cyclic formal having at least one carbon-carbon bond, using a nonvolatile protonic acid as a polymerization catalyst at 100 C. or lower until the conversion reaches 50% and thereafter at a polymerization environment temperature of 115 C. to 140 C. This process includes: a crushing step in which a dry-process crusher is used to obtain a crude polyacetal copolymer crushed to such a degree that when the crude copolymer is screened with a sieve having an opening size of 11.2 mm, 90 parts by weight or more thereof passes therethrough; and a deactivation step in which a basic compound (e) is added to the crude copolymer and the mixture is melt-kneaded to thereby deactivate the polymerization catalyst.

A production method for a polyacetal copolymer that makes deactivation of a catalyst simple and efficient and that achieves a high polymerization yield and high quality using equipment that does not require a cleaning step and a process that involves a simple operation technique. The production method for a polyacetal copolymer uses trioxane as a main monomer and a cyclic ether and/or a cyclic formal having at least one carbon-carbon bond as a comonomer. In the production method, a predetermined heteropoly acid is used as a polymerization catalyst to perform copolymerization, a predetermined salt is added to the reaction product, melt kneading processing is performed, and the polymerization catalyst is deactivated.

A production method for a polyacetal copolymer that makes deactivation of a catalyst simple and efficient and that achieves a high polymerization yield and high quality using equipment that does not require a cleaning step and a process that involves a simple operation technique. The production method for a polyacetal copolymer uses trioxane as a main monomer and a cyclic ether and/or a cyclic formal having at least one carbon-carbon bond as a comonomer. In the production method, a predetermined heteropoly acid is used as a polymerization catalyst to perform copolymerization, a predetermined salt is added to the reaction product, melt kneading processing is performed, and the polymerization catalyst is deactivated.

A high-quality polyacetal produced by a process including supplying a raw material comprising trioxane, a comonomer capable of copolymerizing with trioxane and a non-volatile protonic acid to a reactor of a continuous stirring/mixing machine type; carrying out a polymerization reaction of the raw material to produce a reaction mixture; vaporizing an unreacted monomer to separate the unreacted monomer from the reaction mixture and supplying the unreacted monomer to the raw material supplying; collecting a polyacetal copolymer from the reaction mixture into a collection unit which is arranged downstream from a discharge port and is adjusted to have a gauge pressure of 0.2 kPa or more; and adding a basic compound to the collected polyacetal and then subjecting the resultant mixture to a melt-kneading treatment to deactivate the non-volatile protonic acid.

A high-quality polyacetal produced by a process including supplying a raw material comprising trioxane, a comonomer capable of copolymerizing with trioxane and a non-volatile protonic acid to a reactor of a continuous stirring/mixing machine type; carrying out a polymerization reaction of the raw material to produce a reaction mixture; vaporizing an unreacted monomer to separate the unreacted monomer from the reaction mixture and supplying the unreacted monomer to the raw material supplying; collecting a polyacetal copolymer from the reaction mixture into a collection unit which is arranged downstream from a discharge port and is adjusted to have a gauge pressure of 0.2 kPa or more; and adding a basic compound to the collected polyacetal and then subjecting the resultant mixture to a melt-kneading treatment to deactivate the non-volatile protonic acid.

A process for producing a polyacetal copolymer, the process making catalyst deactivation easy and efficient. Trioxane as a major monomer is copolymerized with one or more comonomers that are a cyclic ether and/or cyclic formal having at least one carbon-carbon bond, using a nonvolatile protonic acid as a polymerization catalyst at 100 C. or lower until the conversion reaches 50% and thereafter at a polymerization environment temperature of 115 C. to 140 C. This process includes: a crushing step in which a dry-process crusher is used to obtain a crude polyacetal copolymer crushed to such a degree that when the crude copolymer is screened with a sieve having an opening size of 11.2 mm, 90 parts by weight or more thereof passes therethrough; and a deactivation step in which a basic compound (e) is added to the crude copolymer and the mixture is melt-kneaded to thereby deactivate the polymerization catalyst.

A process for producing a polyacetal copolymer, the process making catalyst deactivation easy and efficient. Trioxane as a major monomer is copolymerized with one or more comonomers that are a cyclic ether and/or cyclic formal having at least one carbon-carbon bond, using a nonvolatile protonic acid as a polymerization catalyst at 100 C. or lower until the conversion reaches 50% and thereafter at a polymerization environment temperature of 115 C. to 140 C. This process includes: a crushing step in which a dry-process crusher is used to obtain a crude polyacetal copolymer crushed to such a degree that when the crude copolymer is screened with a sieve having an opening size of 11.2 mm, 90 parts by weight or more thereof passes therethrough; and a deactivation step in which a basic compound (e) is added to the crude copolymer and the mixture is melt-kneaded to thereby deactivate the polymerization catalyst.

A high-quality polyacetal copolymer produced by a simple process and in an economical manner. The method includes supplying a raw material including trioxane or the like to a reaction device; obtaining a reaction mixture by carrying out a polymerization reaction of the raw material in the state where the rotating shafts are inclined by 1 to 6 upwards with respect to the horizontal direction H from the introduction opening towards a polyacetal copolymer recovery portion; vaporizing and separating an unreacted monomer from the reaction mixture using a vaporization and separation portion; re-supplying the unreacted monomer to the reaction device; and recovering the polyacetal copolymer from the reaction using a polyacetal copolymer recovery portion.

A high-quality polyacetal copolymer produced by a simple process and in an economical manner. The method includes supplying a raw material including trioxane or the like to a reaction device; obtaining a reaction mixture by carrying out a polymerization reaction of the raw material in the state where the rotating shafts are inclined by 1 to 6 upwards with respect to the horizontal direction H from the introduction opening towards a polyacetal copolymer recovery portion; vaporizing and separating an unreacted monomer from the reaction mixture using a vaporization and separation portion; re-supplying the unreacted monomer to the reaction device; and recovering the polyacetal copolymer from the reaction using a polyacetal copolymer recovery portion.

A high-quality polyacetal copolymer produced by a simple process in an economical manner. The process includes supplying a raw material including trioxane and the like to a reaction device; setting the polymerization environmental temperature to no more than 100 C. until the reaction device conversion rate becomes 0.5, and then carrying out further polymerization; vaporizing and separating unreacted monomers from the reaction mixture at an environmental temperature of at least 115 C. and less than 140 C.; supplying the separated monomers to the raw material supply; and recovering the polyacetal copolymer from the reaction mixture.