Patent ID: 6060167
Filing Date: 2000-05-09
Classification: C08L,C09D,Y10T

Abstract:
In the process of fabricating articles from a substrate having a release coating comprising thermally stable essentially non-fluorocarbon polymer and low melt viscosity fluorocarbon polymer, said coating being from a liquid dispersion, said fluorocarbon polymer consisting essentially of tetrafluoroethylene and less than 0.5 mol % of comonomer, said low melt viscosity fluorocarbon polymer being made by aqueous dispersion polymerization in the presence of initiator, dispersing agent, and chain transfer agent, with said process of fabrication resulting in waxy buildup on the fabrication equipment, the improvement comprising carrying out the aqueous dispersion polymerization to produce said low melt viscosity fluorocarbon polymer in the presence of an effective amount of at least one water soluble additive selected from the group consisting of (i) hydrocarbon carboxylic acids and salts, esters, and peroxides thereof, (ii) alkanols and esters thereof, (iii) ketones, and (iv) fluorosurfactants which contain carbon-hydrogen bonding, said fluorosurfactant being perfluoroalkyl alkane sulfonic acid, the alkyl group containing 5 to 20 carbon atoms and the alkane group containing 1 to 4 carbon atoms, to eliminate the chalking of said coating, said low melt viscosity fluorocarbon polymer having a melting (peak) temperature of at least 315.degree. C. and a melt viscosity of 50 Pa.cndot.s to 1.times.10.sup.5 Pa.cndot.s at 372.degree. C.