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.
Claims24
A process for improving the flexural toughness of moldings formed from a molding material comprising:
- incorporating poly-1,3-dioxepane, poly-1,3-dioxolane, polytetrahydrofurane or mixtures thereof into the molding material;
- and
- forming a molding from the molding material, wherein the molding has increased elongation at break compared to a molding without the poly-1,3-dioxepane, poly-1,3-dioxolane, polytetrahydrofurane, or mixture thereof;
- the molding material comprising:
- an oxymethylene polymer mixture comprising:
- (B1.1). from 10 to 90% by weight of a polyoxymethylene homopolymer or a copolymer containing a majority of oxymethylene units, with a weight-average molar mass (Mw) in the range from above 60,000 to 200,000 g/mol, and
- (B1.2). from 10 to 90% by weight of a copolymer containing a majority of oxymethylene units, with a weight-average molar mass (Mw) in the range of 10,000 to 60,000 g/mol;
- and
- 40 to 70% by volume of sinterable pulverant metal, sinterable pulverant metal alloy, sinterable pulverant ceramic powders or mixtures thereof, based on the molding material;
- wherein, the copolymer in B1.2 is a polyoxymethylene copolymer, at least 90% by weight of which, based on the copolymer, is derived from trioxane and 1,3-dioxepane as monomers and butylal as regulator, with a proportion of 1,3-dioxepane, based on the copolymer, in the range from 1 to 30% by weight, and a proportion of butylal, based on the copolymer, in the range from 0.01 to 2.5% by weight, the % by weight being based on the copolymer and the molecular weights are determined by gel permeation chromatography or size exclusion chromatography;
- and, if B1.1 is a copolymer containing a majority of oxymethylene units, the copolymer in B1.1 is a polyoxymethylene copolymer, at least 90% by weight of which, based on the copolymer, is derived from trioxane and 1,3-dioxepane as monomers and butylal as regulator, with a proportion of 1,3-dioxepane, based on the copolymer, in the range from 1 to 30% by weight, and a proportion of butylal, based on the copolymer, in the range from 0.01 to 2.5% by weight, the % by weight being based on the copolymer and the molecular weights are determined by gel permeation chromatography or size exclusion chromatography;
- and
- wherein the copolymer in B1.2 has a polydispersity Mw/Mn in the range from 3 to 5.
A process for improving the flexural toughness of moldings comprising providing a molding formed from molding materials comprising a mixture 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:
- incorporating poly-1,3-dioxepane, poly-1,3-dioxolane, polytetrahydrofurane or mixtures thereof in the molding material;
- and
- forming a molding from the molding material;
- wherein the molding has increased elongation at break compared to moldings without the poly-1,3-dioxepane, poly-1,3-dioxolane, polytetrahydrofurane, or mixture thereof;
- wherein the molding material is filled with sinterable pulverant metal, metal alloy, ceramic powders, or mixtures thereof;
- wherein the component B1.1 has a polydispersity Mw/Mn in the range from 3 to 5.
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 the mixture of:
- B1.) from 50 to 97% by weight of a mixture, 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;
- 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;
- wherein component B1.1 has a polydispersity Mw/Mn in the range from 3 to 5.
Dependencies are inferred from the claim text.