Thermally stable polyoxymethylene compositions

Patent metadata

Field	Value
Publication number	US-10294361-B2
Application number	US-201415106079-A
Country	US
Kind code	B2
Filing date	Oct 21, 2014
Priority date	Dec 19, 2013
Publication date	May 21, 2019
Grant date	May 21, 2019

Abstract

Polyoxymethylene compositions either consisting essentially of: polyoxymethylene polymer; at least pme amine polymer selected from the group consisting of polyacrylamides, polyallylamines, polyacrylic hydrazide, polymethacrylic hydrazide, polyaminoalkyl acrylate, polyaminoalkyl methacrylate, poly vinylalkylamine, and mixtures of these; and at least pme polyimide having a melting point that ranges between 20° C. below the melting point of (a) to 20° C. above the melting point of the polyoxymethylene polymer.

First claim

What is claimed is:

1. A polyoxymethylene composition consisting essentially of:
(a) 95.85 to 99.94 weight percent polyoxymethylene polymer,
(b) 0.4 to 0.6 weight percent of an amine polymer selected from the group consisting of polyacrylamides, polyallylamines, polyacrylic hydrazide, polymethacrylic hydrazide, polyaminoalkyl acrylate, polyaminoalkyl methacrylate, poly vinylalkylamine, and mixtures of these;
(c) 0.008 to 0.08 weight percent of a polyamide having a melting point of about 140° C. to about 240° C. and wherein said melting point ranges between 40° C. below the melting point of (a) to 40° C. above the melting point of (a), and
(d) 0.01 to 4.0 weight percent of an antioxidant, wherein the polyoxymethylene composition, when molded, exhibits:
a tensile creep to 10% strain at 90° C. and 25 MPa pressure of at least 0.32 minutes, as determined according to ASTM D2990;
a time to mold deposit of at least 12 hours; and
a thermally evolved formaldehyde of less than 0.50 percent, as measured at 250° C. for a period of 0.5 hours.

2. The polyoxymethylene composition of claim 1 , wherein (c) is an aliphatic polyamide.

3. The polyoxymethylene composition of claim 2 , wherein the aliphatic polyamide (c) is polyamide 66/610/6 terpolymer.

4. The polyoxymethylene composition of claim 1 , wherein (b) is selected from the group consisting of polyacrylamides, polyallylamines, polyvinylalkylamines, and mixtures of these.

5. The polyoxymethylene composition of claim 1 , wherein the antioxidant is a hindered phenolic antioxidant.

Assignees

• Du Pont

Inventors

• Kato Makoto

Classifications

• C08L77/06

  Polyamides derived from polyamines and polycarboxylic acids (C08L77/10 takes precedence) · CPC title

• C08L33/26

  Homopolymers or copolymers of acrylamide or methacrylamide · CPC title

• C08K5/005

  Stabilisers against oxidation, heat, light, ozone · CPC title

• C08K5/13

  Phenols; Phenolates · CPC title

• C08L59/02 Primary

  Polyacetals containing polyoxymethylene sequences only · CPC title