Process for preparing rubber-containing styrene resins

Claim 2

IN A PROCESS FOR PREPARING RUBBER-CONTAINING STYRENE RESINS, IN WHICH A SOLUTION OF (A) FROM 2 TO 20 PARTS BY WEIGHT OF BUTADIENE SYNTHETIC RUBBER, DISSOLVED IN (B) 100 PARTS BY WEIGHT OF MONOVINYL AROMATIC MONOMER OR MONOMER MIXTURE COMPRISING MONOVINYL AROMATIC MONOMER AND MONOMER COPOLYMERIZABLE THERE WITH, IS SUBJECTED TO BULK POLYMERIZATION AT LEAST UNTIL PHASE INVERSION HAS OCCURRED AND THEN IS SUBJECTED TO SUSPENSION POLYMERIZATION TO OBTAIN THE RESIN PRODUCT, IN WHICH THE BULK POLYMERIZATION IS CARRIED OUT IN A VESSEL HAVING WALL MEANS DEFINING A CIRCULATORY FLOW PATH FOR THE SOLUTION UNDERGOING POLYMERIZATION AND HAVING AN IMPELLER FOR EFFECTING CIRCULATORY FLOW OF THE SOLUTION THROUGH SAID PATH AND IMPOSING SHEAR ON THE RUBBER PARTICLES THAT FORM IN THE SOLUTION DURING BULK POLYMERIZATION AND HAVING AN IMPELLER FOR POLYMERIZATION STEP WHICH CONSISTS ESSENTIALLY OF ROTATING SAID IMPELLER BEGINING AT THE LATEST BY THE TIME WHEN PHASE INVERSION COMMENCES, AND THEREY CONTINOUSLY AND REPEATEDLY CIRCULATING THE ENTIRELY OF THE POLYMERIZATION LIQUID DURING THE REMAINDER OF THE BULK POLYMERIZATION STEP IN UNIDIRECTIONAL, NON-TURBULENT, LAMINAR FLOW THROUGH A SHEAR ZONE AT A UNIFORM RATE OF FROM 4 TO 36 CIRCULATIONS PER MINUTE OF THE ENTIRELY OF THE POLYMERIZATION LIQUID AND IN THE RANGE CALCULATED BY THE FORMULA -0.064X2+3X+6> NUMBER OF CYCLES OF CIRCULATION OF THE ENTIRE POLYMERIZATION LIQUID PER MINUTE> -0.064X2+3X-10, WHEREIN X IS THE WEIGHT OF RUBBER DISSOLVED IN 100 PARTS OF (B), SAID SHEAR ZONE BEING DEFINED BY A RADIAL FLOW TURBINE IMPELLER WHOSE BLADES EXTEND SUBSTANTIALLY TO THE WALL OF SAID PATH WHEREBY SAID SHEAR ZONE EXTENDS SUBSTANTIALLY ENTIRELY ACROSS SAID PATH SO THAT AS THE POLYMERIZATION LIQUID MOVES UNIDIRECTIONALLY THROUGH THE SHEAR ZONE ITS DIRECTION OF FLOW IS CHANGED BY SAID BLADES FROM A DIRECTION PARALLEL TO THE AXIS OF ROTATION OF SAID IMPELLER TO A DIRECTION RADIALLY THEREOF, AND SAID POLYMERIZATION LIQUID IS SIMULTANEOUSLY SUBJECTED TO A UNIFORM SHEAR FORCE AT A MEAN SHEAR RATE OF FROM 60 TO 200 SEC-1 WHEREIN MEAN SHEAR RATE =2.7 $PVGC/$ IN WHICH PV= POWER CONSUMPTION FOR OPERATING THE IMPELLER PER UNIT VOLUME OF THE POLYMERIZATION LIQUID, IN UNITS KG/SEC. M2 GC= GRAVITATION CONVERSION FACTOR, IN INITS KG. M/KG SEC2 $= VISOSITY OF POLYMERIZATION LIQUID, IN INITS KG/M. SEC THE ROTATION OF THE IMPELLER BEING CONTINUED UNTIL THE CONVERSION OF MONOMER TO POLYMER HAS INCREASED FROM 4 TO 35 PERCENT MORE THAN SAID CONVERSION AT THE TIME OF COMMENCEMENT OF PHASE INVERSION IN THE POLYMERIZATION LIQUID AND THE ENT8TIRETY OF SAID POLYMERIZATION LIQUID HAS BEEN CIRCULATED THROUGH SAID SHEAR ZONE FROM 200 TO 2200 TIMES AND IS HIGHER THAN THE VAUE CALCULATED FROM THE FORMULA

Claim 3

A process according to claim 1, wherein the monovinyl aromatic monomer is styrene.

Claim 4

A process according to claim 1, wherein the monovinyl aromatic monomer is styrene and the monomer copolymerizable with the monovinyl aromatic monomer is acrylonitrile.

Claim 5

A process according to claim 1, wherein the synthetic rubber is polybutadiene.

Claim 6

A process according to claim 1, wherein the synthetic rubber is butadiene copolymer rubber.

Claim 7

A process according to claim 1, in which the circulation and shear are effected by rotating a radial flow, flat non-pitched blade or curved non-pitched blade impeller mounted adjacent the bottom wall of the reaction vessel to direct the polymerization reaction liquid to the wall of the vessel, thence upwardly along said wall, thence toward the center of the vessel and then downwardly through an inner cylinder having substantially the same diameter as the impeller.

Claim 8

A process according to claim 1, wherein the rate of circulating the polymerization liquid is from 10 to 30 circulations/min.

Claim 9

A process according to claim 1, wherein the rate of circulating the polymerization liquid is from 15 to 25 circulations/min.