Novel tetrafluoroethylene resins and their preparation

Claim 1

A PARTICULATE POLYMERIC TETRAFLUOROETHYLENE RESIN, CONSISTING ESSENTIALLY OF FLUOROETHYLENE OF THE GROUP CONSISTING OF TETRAFLUOROETHYLENE, PERFLUOROALKYL TRIFLUOROETHYLENES OF 3 TO 10 CARBON ATOMS, AND OXYPERFLUOROALKYL TRIFLUOROETHYLENES OF 3 TO 10 CARBONS AS COMBINED MONOMER AND COMPRISING AT LEAST 98 WEIGHT PERCENT COMBINED TETRAFLUOROETHYLENE, PREDOMINANTLY COMPRISING SPHEROIDAL PARTICLES 0.05 TO 0.5 MICRON IN DIAMETER, HAVING AN AVERAGE PARTICLE DIAMETER IN THE RANGE OF 0.12 TO 0.35 MICRON, A STANDARD SPECIFIC GRAVITY OF LESS THAN 2.235, AND A SPECIFIC MELT VISCOSITY OF AT LESAT 1X10**9 POISES AT 380*C., SAID RESIN BEING ONE OBTANED BY SUBJECTING TETRAFLUOROETHYLENE TO POLYMERIZING CONDITIONS OF TEMPERATURE AND PRESSURE IN AN AQUEOUS MEDIUM HAVING DISSOLVED THEREIN A FREE-RADICAL POLYMERIZATION INITIATOR, A DISPERSING AGENT, AND, PRESENT AT LEAST DURING AND COEXTENSIVELY WITH THE POLYMERIZATION OF THE FINAL 30 PERCENT OF THE TETRAFLUOROETHYLENE POLYMERIZED, A MODIFIER IN AMOUNTS INEFFECTIVE TO PREVENT RESIN HAVING THE AFORESAID CHARACTERISTICS FROM BEING OBTAINED, BUT CUMULATIVELY EFFECTIVE TO MAINTAIN THE OVERALL RATE OF POLYMERIZATION AT LEAST 5 PERCENT BELOW THAT OBTAINING FOR THE POLYMERIZATION OF AN EQUAL QUANTITY OF TETRAFLUOREOTHYLENE IN AN IDENTICAL REACTION MEDIUM CONTINUOUSLY SATURATED WITH TETRAFLUOROETHYLENE AT THE SAME TEMPERATURE AND PRESSURE IN THE ABSENCE OF SAID MODIFIER, SAID MODIFIER BEING SELECTED FROM THE GROUP CONSISTING OF NON-POLYMERIZABLE CHAIN TRANSFER AGENTS CONTAINING AT LEAST ONE COVALENTLYBOUND NON-METALLIC MONOVALENT ATOM OTHER THAN FLUORINE, PERFLUOROALKYL TRIFLUOROETHYLENE OF 3 TO 10 CARBON ATOMS, AND OXPERFLUOROALKYL TRIFLUOROETHYLENES OF 3 TO 10 CARBON ATOMS.