摘要:
The present invention relates to a method for refining polyoxymethylene dialkyl ethers by catalytic hydrogenation using a slurry bed, wherein, using a slurry bed reactor of refining by hydrogenation, an equilibrium system of products containing polyoxymethylene dialkyl ethers is refined by catalytic hydrogenation, so as to remove formaldehyde contained therein. The refining method by hydrogenation described in the present invention is able to remarkably increase the extracting rate of polyoxymethylene dialkyl ethers, and the polyoxymethylene dialkyl ethers obtained after subsequent rectification have purity greater than 99.5%, yield greater than 97% and atom utilization ratio close to 100%.
摘要:
A process for producing a polyacetal copolymer, the process making catalyst deactivation easy and efficient, requiring no cleaning step, merely requiring simple equipment and simple operation techniques, and rendering a high polymerization yield and high quality possible. In the invention, trioxane as a major monomer (a) is copolymerized with one or more comonomers (b) 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 (c) at a polymerization environment temperature of 100°C or lower until the conversion reaches 50% and thereafter at a polymerization environment temperature in the range 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 (d2) crushed to such a degree that when the crude copolymer (d2) 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 ingredient (d2) and the mixture is melt-kneaded to thereby deactivate the ingredient (c).
摘要:
Provided is 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 (a) and a cyclic ether and/or a cyclic formal having at least one carbon-carbon bond as a comonomer (b). In the production method, a predetermined heteropoly acid is used as a polymerization catalyst (c) to perform copolymerization, a predetermined salt (d) is added to the reaction product, melt kneading processing is performed, and the polymerization catalyst (c) is deactivated. It is preferable that the heteropoly acid be selected from among phosphomolybdic acid, phosphotungstic acid, and the like. It is preferable that the salt (d) be selected from among sodium carbonate, sodium bicarbonate, sodium formate, and the like.
摘要:
Kontinuierliches Verfahren zur Entfernung instabiler Anteile aus rohem Oxymethylencopolymerisat, das noch Katalysatoren, monomere Ausgangsstoffe und instabile Anteile enthält, durch Behandlung mit Desaktivatoren, gegebenenfalls in Anwesenheit von Hilfsmitteln in einer Druckzone und darauffolgende Entfernung von flüchtigen Anteilen in einer Entspannungszone gegebenenfalls in Anwesenheit von Stabilisatoren, bei dem das Rohpolymerisat unmittelbar nach Beendigung des Polymerisationsschrittes in Abwesenheit von Desaktivatoren und Hilfsmitteln vollständig aufgeschmolzen wird und die Desaktivatoren allein oder zusammen mit Hilfsmitteln anschließend in mindestens einer Druckzone in die erhaltene Polymerschmelze unter Druck eingearbeitet werden. Durch dieses Verfahren werden Abbauerscheinungen vermieden und deutlich bessere Eigenschaftswerte erhalten.
摘要:
A process for producing a polyacetal copolymer, the process making catalyst deactivation easy and efficient, requiring no cleaning step, merely requiring simple equipment and simple operation techniques, and rendering a high polymerization yield and high quality possible. In the invention, trioxane as a major monomer (a) is copolymerized with one or more comonomers (b) 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 (c) at a polymerization environment temperature of 100°C or lower until the conversion reaches 50% and thereafter at a polymerization environment temperature in the range 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 (d2) crushed to such a degree that when the crude copolymer (d2) 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 ingredient (d2) and the mixture is melt-kneaded to thereby deactivate the ingredient (c).
摘要:
The purpose of the present invention is to provide a high-quality polyacetal copolymer economically advantageously by a simple process. The present invention comprises: a raw material supply step (S1) of 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; a polymerization reaction step (S2) of carrying out a polymerization reaction of the raw material to produce a reaction mixture; an unreacted monomer re-supply step (S3) of vaporizing an unreacted monomer to separate the unreacted monomer from the reaction mixture and supplying the unreacted monomer to the raw material supply step; a polyacetal copolymer collection step (S4) of collecting a polyacetal copolymer from the reaction mixture into a collection unit which is arranged downstream from a discharge port and is so adjusted as to have a gauge pressure of 0.2 kPa or more; and a deactivation step (S5) of adding a basic compound to the polyacetal copolymer that has been collected in the polyacetal copolymer collection step and then subjecting the resultant mixture to a meltkneading treatment to deactivate the non-volatile protonic acid.
摘要:
Beschrieben werden Formmassen und die daraus hergestellten Formkörper enthaltend a) Polyoxymethylen, bei dem mindestens 50 % der Endgruppen Hydroxylgruppen sind, das einen Schmelzflussindex MVR von kleiner als 20 cm 3 / 10 Minuten aufweist, gemessen nach ISO 1133 bei 190 °C und 2,16 kg, und dessen Anteil an niedermolekularen Bestandteilen mit Molekulargewichten unterhalb von 10.000 Dalton weniger als 15 Gew. % beträgt, bezogen auf die Gesamtmasse des Polyoxymethylens, und b) ein thermoplastisches Elastomer. Die aus diesen Formmassen hergestellten Formkörper zeichnen sich durch eine sehr hohe Kerbschlagzähigkeit aus.