Mass polymerization process for ABS polyblends

Claim 2

A continuous mass polymerization process for preparing an ABS polymer having a matrix phase comprising a copolymer of a monoalkenyl aromatic monomer and an ethylenically unsaturated nitrile monomer and a dispersed phase comprising rubber particles having a weight average particle size of from about 0.1 to 10 microns, which process comprises: (i) continuously charging a feed stream of a monoalkenylaromatic monomer having. dissolved therein from 3 to 33% by weight of a diene rubber to a stirred reactor; (ii) simultaneously and continuously charging a separate feed stream of an ethylenically unsaturated nitrile monomer to the stirred reactor; (iii) both said feed streams being charged to a polymerizing...mixture having a polymer solids level above that at which phase inversion occurs and up to about 70% by weight polymer solids based on the weight of the polymerization mixture; (iv) continuously polymerizing the mixture while maintaining stirring such that the polymerizing mixture has a substantially uniform composition and such that the rubber is dispersed in the polymerizing mixture as rubber particles having a weight average particle size of about 0.1 to 10 microns; and (v) continuously separating an ABS polymer from the partially polymerized mixture from step (iv).

Claim 3

A process according to Claim . l,in which the monomer mixture in the reactor comprises 15 to 60% by weight of the ethylenically unsaturated nitrile monomer.

Claim 4

A process according to Claim 2, in which the monomer mixture in the reactor comprises 25 to 60% by weight of acrylonitrile.

Claim 5

A process according to any of Claims 1 to 3, in which the rubber in (i) is added in sufficient quantities to provide an ABS polymer in which the rubber provides from 14 to 25% of the weight of the polymer.

Claim 6

A process according to any of Claims 1 to 4, in which the rubber in (i) has a viscosity average molecular weight of from 5,000 to 50,000.

Claim 7

A process according to any of Claims 1 to 5, in which the rubber is dispersed in the reactor as particles with a weight average particle size of from 0.2 to 0.5 micron.

Claim 8

A process according to any of Claims 1 to 6, in'which the reactor is charged with a solution which comprises styrene and a diene rubber with a viscosity average molecular weight of from 5,000 to 50,000, said solution comprising from 10 to 30% by weight of the rubber, and with a separate stream of acrylonitrile so as to provide a polymerizing mixture with a substantially uniform composition comprising from 25 to 60% of acrylonitrile (based on the weight of monomers present) in which the rubber is dispersed as particles with a weight average particle size of from 0.2 to 0.5 micron.

Claim 9

A process according to any of Claims 1 to 7, in which the polymerization is performed in a single reactor operating at a monomer to polymer conversion of 30 to 99%.

Claim 10

A process according to any of Claims 1 to 7, in which the polymerization is carried out in two reactors in which a first reactor operates at a polymer solids content of from 35 to 55% and continually feeds a partially polymerized mixture to a second.reactor in which the polymerization is advanced to the desired level.

Claim 11

A process according to any of Claims 1 to 7, in which: A. the rubber and monomers are fed to a polymerization mixture with a polymer solids level of 35 to 55%, in a first reactor which is stirred to provide a substantially uniform composition, said monomers and rubber being fed along with from 10 to 30% based on the monomers charged of a diluent, and an effective amount of an initiator selected from tert-butyl perbenzoate, tert-butyl peroxy isopropyl carbonate, tert-butyl peroctoate, tert-butyl peroxy isononoate and tert-butyl, 2-ethylhexyl monoperoxy carbonate; B . a first partially polymerized stream.from the first .reactor is further polymerized in the second reactor operated continuously with a substantially uniform composition throughout to produce a second partially polymerized stream with up to 70% polymer solids content; and C . an ABS polymer is separated from the second partially polymerized stream using a wiped film devolatilizer.

Claim 12

An ABS polymer comprising from 27 to 40% by weight of acrylonitrile and a diene rubber content of from 14 to 25%.

Claim 13

An ABS polymer comprising from 27 to 40% by weight of acrylonitrile and a diene rubber content of from 14 to 25%.

Claim 14

An ABS polymer according to Claim 11, prepared by a process according to any of Claims 1 to 13.

Claim 15

A continuous mass polymerization process for preparing an ABS polymeric polyblend having a matrix phase copolymer of monoalkenyl aromatic and alkenyl nitrile monomers and dispersed conjugated diene rubber phase grafted with said monomers, the steps comprising: A. continuously charging a solution of a monoalkenyl aromatic monomer having about 3 to 18% by weight of a diene rubber dissolved therein simultaneously with a separate feed-stream of alkenyl nitrile monomer to a first back mixed reaction zone, said first zone operating at about 20 to 50% steady state conversion of said monomer, said rubber being dispersed as rubber particles having a particle size of about 0.1 to 10 microns, said particles having present about 0.4 to 5 parts of said monomers, wherein, at least a portion of said monomers is present as occluded and grafted copolymer of said monomers, forming a first partially polymerized mixture, B . continuously withdrawing and charging said first partially polymerized mixture to a second reaction zone, said first mixture being polymerized in said second reaction zone forming a second partially polymerized mixture continuing 50 to 99% of ABS polyblend solids, C . continuously withdrawing said second mixture from said second reaction zone and separating said ABS polyblend solids from said partially polymerized mixture as said ABS polyblend having a matrix phase copolymer of said monomers with a dispersed diene rubber phase as rubber particles having present grafted and occluded copolymer of said monomers in an amount of about 0.4 to 5 parts per part of rubber, said rubber particles having an average particle size of about 0.1 to 10 microns.

Claim 16

A continuous mass polymerization process for preparing an ABS polymeric polyblend having a matrix phase copolymer of monoalkenyl aromatic and alkenyl nitrile monomers and dispersed conjugated diene rubber phase grafted with said monomers, the steps comprising: A. continuously charging a solution of a monoalkenyl aromatic monomer having about 3 to 18% by weight of a diene rubber dissolved therein simultaneously with a separate feed-stream of alkenyl nitrile monomer to a first back mixed reaction zone, said first zone operating at about 20 to 50% steady state conversion of said monomer, said rubber being dispersed as rubber particles having a particle size of about 0.1 to 10 microns, said particles having present about 0.4 to 5 parts of said monomers, wherein, at least a portion of said monomers is present as occluded and grafted copolymer of said monomers, forming a first partially polymerized mixture, B . continuously withdrawing and charging said first partially polymerized mixture to a second reaction zone, said first mixture being polymerized in said second reaction zone forming a second partially polymerized mixture continuing 50 to 99% of ABS polyblend solids, C . continuously withdrawing said second mixture from said second reaction zone and separating said ABS polyblend solids from said partially polymerized mixture as said ABS polyblend having a matrix phase copolymer of said monomers with a dispersed diene rubber phase as rubber particles having present grafted and occluded copolymer of said monomers in an amount of about 0.4 to 5 parts per part of rubber, said rubber particles having an average particle size of about 0.1 to 10 microns.