Polyamide compositions

Abstract

Polyamides, such as polyamide compositions based on nylon-6 (PA 6) or nylon-6,6 (PA 66) and including melamine cyanurate, natural quartz powder, and glass fibres have improved heat resistance, flame retardancy, and isotropic shrinkage characteristics.

What is claimed is: 
     
         1 . A polyamide composition comprising:
 A) about 5% to about 96.9% by weight of polyamide;   B) about 1% to about 60% by weight of quartz powder, wherein the quartz powder is a powder of naturally occurring quartz crystals and not of quartz glass, and the powder particles have a d95 of about 5 to about 250 μm;   C) about 2% to about 8% by weight of chopped long glass fibers having a starting length of about 1 to about 50 mm;   D) about 0.1% to about 40% by weight of melamine cyanurate, and   E) about 0.01% to about 30% by weight of titanium dioxide.   
     
     
         2 . The polyamide composition according to  claim 1 , wherein the titanium dioxide has particles with a median particle size of 90 nm to 2000 nm with base structures of anatase or rutile form. 
     
     
         3 . The polyamide composition according to  claim 1 , wherein the composition does not contain ground glass. 
     
     
         4 . The composition according to  claim 1 , further comprising F) about 0.01% to 5% by weight lubricants and/or demouldlng agents. 
     
     
         5 . The composition according to any of  claim 4 , wherein the composition does not contain ground glass. 
     
     
         6 . The composition according to  claim 4 , wherein as component F) long-chain fatty acids and the ester derivatives or amide derivatives thereof are used. 
     
     
         7 . The composition according to  claim 6 , wherein the long-chain fatty acid is at least one of stearic acid, salts of stearic acid, behenic acid, and salts of behenic acid. 
     
     
         8 . The composition according to  claim 7 , wherein the long-chain fatty acid is calcium stearate or zinc stearate. 
     
     
         9 . The composition according to  claim 6 , wherein the ester derivatives or amide derivatives are ethylenebisstearylamlde, montan waxes, and low molecular weight polyethylene or polypropylene waxes. 
     
     
         10 . The composition according to  claim 1 , wherein the polyamide comprises at least one of nylon-6 and nylon-6,6. 
     
     
         11 . The composition according to  claim 1 , further comprising K) about 0.01% to about 50% by weight of the at least one filer or reinforcer other than components B) and C). 
     
     
         12 . The composition according to  claim 11 , wherein the sum total of all the percentages by weight of all the components is always 100. 
     
     
         13 . The composition according to  claim 4 , further comprising L) at least one further additive other than components D) to K). 
     
     
         14 . The composition according to  claim 13 , wherein the composition comprises about 0.01% to 20% by weight of component L), based on the overall composition, in which case amounts of the other components are reduced to such an extent that the sum total of all the percentages by weight is always 100%. 
     
     
         15 . The composition according to  claim 11 , wherein the at least one further filler and/or reinforcer comprises at least one of talc, mica, silicate, amorphous wollastonite, kaolin, amorphous silicas, nanoscale minerals, magnesium carbonate, chalk, feldspar, barium sulphate, fibrous fillers based on carbon fibers, reinforcers based on carbon fibres, and untreated, surface-modified or sized reinforcers made from glass. 
     
     
         16 . The composition according to  claim 1 , wherein the composition has a heat deflection temperature (HDT) of greater than 130° C. per DIN EN ISO 75-1,-2. 
     
     
         17 . The composition according to  claim 1 , wherein:
 the polyamide is semi-crystalline polyamide, and has a viscosity number determined in a 0.5% by weight solution in 96% by weight sulphuric acid at 25° C. to ISO 307 of 80 to 180 ml/g;   the quartz is a powder having a median particle size (d50) of about 2 μm to about 50 μm, a d95 of 10 to 150 μm, and a length to thickness ratio of less than 5;   the glass fibres have a diameter of 7 to 18 μm;   the melamine cyanurate is in the form of particles having a median diameter of 0.1 μm to 100 μm; and   the titanium dioxide has particles with a median particle size of 90 nm to 2000 nm with base structures of anatase or rutile form.   
     
     
         18 . The composition according to  claim 17 , wherein:
 the polyamide comprises at least one of nylon-6 and nylon-6,6; and   the composition does not contain ground glass.