Patent ID: 7241844
Filing Date: 2007-07-10
Classification: C08F,C08J,C08K,C08L

Abstract:
1. A method for cross-linking isotactic polymer, wherein the method comprises the steps of a. introducing a cross-linking agent to an isotactic polymer and an accelerator which is tetramethyl thiuram monosulphide or tetramethyl thiuram disulphide, wherein the cross-linking agent comprises a peroxide and a sulfur, wherein the peroxide comprises an activity ranging from about 40% to about 100%, and wherein the ratio of the accelerator to sulfur or peroxide ranges from 1:4 to 1:10 depending on the activity; b. shearing the isotactic polymer in a high shear rate mixer; c. initiating cross-linking with the peroxide at a temperature of about 140 degrees Celsius while using the accelerator to inhibit partially the cross-linking of the peroxide; d. forming macro radicals during the cross-linking; and e. forming macromolecular chains of isotactic polymer with sulfur bridges without the need for high torque, wherein the accelerator ensures that the cross-linking and the formation of sulfur bridges occurs simultaneously.