E.i. Dupont De Nemours and Company

Delrin Usa, LLC

Dupont Polymers, Inc.

Ramabhadra Ratnagiri

Henry Keith Chenault

Lech Wilczek

Xiyun (Serene) Fan

Described herein are polyoxymethylene (POM) compositions comprising polyoxymethylene and styrene maleic anhydride (SMA) copolymers or modified SMA copolymers, said POM compositions exhibiting improved physical properties such as heat deflection temperatures compared to POM compositions which do not comprise SMA copolymers.

Polyoxymethylene compositions

Polyoxymethylene compositions, articles comprising these compositions, and processes of making the compositions, comprising: a) at least one polyoxymethylene polymer; b) about 0.1 to about 5 wt. % of poly alpha-1,3-glucan having a d90 particle size of 50 microns or less; c) optionally, at least one additive selected from the group consisting of nucleating agents, waxes, ultraviolet stabilizers, colorants, antioxidants, formaldehyde scavengers, lubricants, and mixtures of these; wherein an article molded from said polyoxymethylene composition exhibits a formaldehyde emission of 1 weight percent or less when measured according to TEF test method.

Polyoxymethylene compositions with polyoxymethylene polymers polymer/polyol additives having a core-link-arm structure. Upon molding, these compositions exhibit stable melt viscosity and simultaneous improvement in notched Izod impact strength and/or decreased relative apparent capillary melt viscosity, and/or increased elongation at break, relative to polyoxymethylene compositions lacking such core-link-arm structure additives.

Polyoxymethylene compositions with branched polymers

Compositions comprising polyoxymethylene polymers and at least one organopolysiloxane polymer. Adding organopolysiloxane polymers to polyoxymethylene polymers provides compositions that exhibit at least a 50 percent reduction in melt viscosity compared to the melt viscosity of an identical, melted composition lacking the organopolysiloxane polymer, and promote easier molding of the compositions into complex article shapes.

Processes for improving melt flow properties of molten compositions with polyoxymethylene polymers and polymer/polyol additives having a certain core-link-arm structure, which include: obtaining melt viscosity stability while improving notched Izod, decreasing relative apparent capillary melt viscosity, and increasing elongation at break relative to molten compositions of polyoxymethylene polymers without the polymer/polyol additives.

Obtaining melt viscosity stability of polyoxymethylene compositions

Described herein are compositions comprising (a) 92 to 99 weight percent, of polyoxymethylene with number average molecular weight from 65,000 to 250,000 g/mole; and (b) 1 to 8 weight percent of an imidized acrylic resin obtained by treating an acrylic polymer with a monoalkyl amine, wherein the weight percents of a and b are based on their combined weight, and monoalkyl group has from one to five carbon atoms, the degree of imidization is 20% to 100% and the acid level is from 0 to about 2 weight percent of the imidized acrylic resin. The composition has significantly higher heat deflection temperature than the neat polyoxymethylene. Processes of increasing heat deflection temperature of POM compositions are described herein by blending (a) and (b), wherein the resultant melt-mixed composition has a 200% increase or greater in time to 5% creep strain relative to the same melt-mixed composition lacking (b).

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Wilmington, DE, United States of America

Ramabhadra Ratnagiri