Process for improving the flexural toughness of moldings
AssigneeBASF SE
InventorsBERND-STEFFEN VON BERNSTORFF, Marie-Claire HERMANT, Martin BLÖMACHER
Life of this patent
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Abstract
Poly-1,3-dioxepane, poly-1,3-dioxolane, polytetrahydrofurane or mixtures thereof are used in molding materials comprising polyoxymethylene or a copolymer containing a majority of oxymethylene units, for improving the flexural toughness of moldings formed from the molding materials.
Claims21
-14. (canceled)
A process for improving the flexural toughness of moldings formed from molding materials comprising:
- incorporating poly-1,3-dioxepane, poly-1,3-dioxolane, polytetrahydrofurane or mixtures thereof into a molding material comprising polyoxymethylene or a copolymer containing a majority of oxymethylene units, for improving the flexural toughness of moldings formed from the molding materials, wherein a polyoxymethylene copolymer with a weight-average molar mass (MW) of the copolymer in the range from 20 000 to 200 000 g/mol, at least 90% by weight of which, based on the polymer, derived from trioxane and 1,3-dioxepane as monomers and butylal as regulator, with a proportion of 1,3-dioxepane, based on the polymer, in the range from 1 to 30% by weight, and a proportion of butylal, based on the polymer, in the range from 0.01 to 2.5% by weight is employed, the % by weight being based on the copolymer and the molecular weights are determined by gel permeation chromatography or size exclusion chromatography.
A process for improving the flexural toughness of moldings formed from molding materials comprising a mixture of different polyoxymethylene homo- or copolymers comprising from 10 to 90% by weight of a polyoxymethylene homo- or copolymer with a weight-average molar mass (MW) in the range from above 60 000 to 200 000 g/mol as component B1.1 and from 10 to 90% by weight of a polyoxymethylene copolymer with a weight average molar mass (MW) in the range from 10 000 to 60 000 g/mol, as component B1.2, comprising the step of incorporating poly-1,3-dioxepane, poly-1,3-dioxolane, polytetrahydrofurane or mixtures thereof in the molding material.
A molding material comprising
- A.) from 40 to 70% by volume of a sinterable pulverant metal or a sinterable pulverant metal alloy or a sinterable pulverant ceramic or mixtures thereof;
- B.) from 30 to 60% by volume of a binder comprising of the mixture of:
- B1.) from 50 to 97% by weight of one or more polyoxymethylene homopolymers or copolymers based on the total amount of the component B;
- B2.) from 2 to 35% by weight of one or more polyolefins, based on the total amount of component B;
- B3.) from 1 to 40% by weight of poly-1,3-dioxolane, poly-1,3-dioxepane or polytetrahydrofurane or mixtures thereof, based on the total amount of component B, the sum of B1.), B2.) and B3.) adding up to 100% by weight.
Dependencies are inferred from the claim text.