ABS compositions having trimodal rubber particle distributions and process

Claim 2

A rubber-modified, impact resistant polymeric composition comprising: (a) a matrix including an interpolymer, said interpolymer being polymerized from a monovinylidene aromatic monomer and an ethylenically unsaturated nitrile monomer; and (b) dispersed in said matrix, in the form of discrete particles, from 6 to 40 weight percent, based on total polymeric composition weight, of elastomeric material, wherein the dispersed elastomeric material is characterized by the following three different grafted rubber components: (1) a component of small, emulsion polymerized particles, being from 10 to 90 weight percent of the total elastomeric material and having a volume average diameter from 0.05 micron to 0.25 micron; (2) a component of small, mass polymerized particles, being from 5 to 85 weight percent of the total elastomeric material, and having a volume average diameter from 0.5 micron to 3.0 microns; and (3) a component of large, mass polymerized particles, being from 5.0 to 50 weight percent of the total elastomeric material; said large mass polymerized particles having a volume average diameter greater than the volume average diameter of the small mass polymerized particles; and said large mass polymerized particles having a volume average diameter of from 1.0 microns to 10 microns.

Claim 3

A composition as claimed in Claim 1 wherein grafted rubber component (1) has a volume average diameter of from 0.08 micron to 0.2 micron and is from 20 to 80 percent by weight of the total elastomeric material; grafted rubber component (2) has a volume average diameter of 0.65 micron to 1.5 microns and is from 15 to 75 weight percent of the total elastomeric material; and grafted rubber component (3) has a volume average diameter of from 3.0 microns to 8.0 microns and is from 5 to 30 weight percent of the total elastomeric material.

Claim 4

A composition as claimed in Claim 1 or Claim 2 wherein the interpolymer of the matrix is at least 70 percent by weight of the total composition, the interpolymer including an ethylenically unsaturated nitrile monomer in an amount of from 10 to 40 weight percent and a monovinylidene aromatic monomer in an amount of from 90 to 60 weight percent based on total interpolymer weight.

Claim 5

A composition as claimed in Claim 3 wherein the monovinylidene aromatic monomer is styrene and the ethylenically unsaturated nitrile monomer is acrylonitrile.

Claim 6

A composition as claimed in any one of claims 1 to 4 wherein the interpolymer of the matrix includes styrene, acrylonitrile, and methyl methacrylate.

Claim 7

A composition as claimed in any one of claims 1 to 5, wherein the grafted rubber component (3) particles have a volume average diameter which is at least two times greater than the volume average diameters of the small mass polymerized particles.

Claim 8

A process for preparing a rubber--modified, impact resistant polymeric composition of the type including: (a) a matrix including an interpolymer, said interpolymer being polymerized from a monovinylidene aromatic monomer and an ethylenically unsaturated nitrile monomer; and (b) dispersed in said matrix, in the form of discrete particles, from about 6 to about 40 weight percent, based on total polymeric composition weight, of elastomeric material, characterized by dispersing in the interpolymer matrix elastomeric material of the following three different grafted rubber components: (1) a component of small, emulsion polymerized particles, being from 10 to 90 weight percent of the total elastomeric material and having a volume average diameter from 0.05 micron to 0.25 micron; (2) a component of small, mass polymerized particles, being from 5 to 85 weight percent of the total elastomeric material, and having a volume average diameter from 0.5 micron to 3.0 microns; and (3) a component of large, mass polymerized particles, being from 5.0 to 50 weight percent of the total elastomeric material; said large mass polymerized particles having a volume average diameter greater than the volume average diameter of the small mass polymerized particles; and said large mass polymerized particles having a volume average diameter of from 1.0 microns to 10 microns.

Claim 9

A process for preparing a rubber--modified, impact resistant polymeric composition of the type including: (a) a matrix including an interpolymer, said interpolymer being polymerized from a monovinylidene aromatic monomer and an ethylenically unsaturated nitrile monomer; and (b) dispersed in said matrix, in the form of discrete particles, from about 6 to about 40 weight percent, based on total polymeric composition weight, of elastomeric material, characterized by dispersing in the interpolymer matrix elastomeric material of the following three different grafted rubber components: (1) a component of small, emulsion polymerized particles, being from 10 to 90 weight percent of the total elastomeric material and having a volume average diameter from 0.05 micron to 0.25 micron; (2) a component of small, mass polymerized particles, being from 5 to 85 weight percent of the total elastomeric material, and having a volume average diameter from 0.5 micron to 3.0 microns; and (3) a component of large, mass polymerized particles, being from 5.0 to 50 weight percent of the total elastomeric material; said large mass polymerized particles having a volume average diameter greater than the volume average diameter of the small mass polymerized particles; and said large mass polymerized particles having a volume average diameter of from 1.0 microns to 10 microns.

Claim 10

A process as claimed in Claim 7 wherein grafted rubber component (1) has a volume average diameter of from 0.08 micron to 0.2 micron and is from 20 to 80 percent by weight of the total elastomeric material; grafted rubber component (2) has a volume average diameter of 0.65 micron to 1.5 microns and is from 15 to 75 weight percent of the total elastomeric material; and grafted rubber component (3) has a volume average diameter of from 3.0 microns to 8.0 microns and is from 5 to 30 weight percent of the total elastomeric material.

Claim 11

A process as claimed in Claim 7 or Claim 8 wherein the interpolymer of the matrix is at least 70 percent by weight of the total composition, the interpolymer comprising an ethylenically unsaturated nitrile monomer in an amount of from 10 to 40 weight percent and a monovinylidene aromatic monomer in an amount of from 90 to 60 weight percent based on total interpolymer weight.

Claim 12

A process as claimed in Claim 9 wherein the monovinylidene aromatic monomer is styrene and the ethylenically unsaturated nitrile monomer is acrylonitrile.

Claim 13

A process as claimed in any one of claims 7 to 10 wherein the interpolymer of the matrix is prepared from styrene, acrylonitrile and methyl methacrylate.

Claim 14

A process as claimed in any one of claims 7 to 11 wherein the grafted rubber component (3) particles have a volume average diameter which is at least two times greater than the volume average diameters of the small mass polymerized particles.

Claim 15

A process as claimed in any one of claims 7 to 12 wherein (1) the elastomeric material is a rubbery polymer; (2) at least some of the ungrafted interpolymer is prepared during grafting of at least one of the three types of component rubbery particles; and (3) the weight average molecular weight of the matrix ungrafted interpolymer, from all sources together, is in the range from 40,000 to 300,000.

Claim 16

A process as claimed in any one of claims 7 to 13 wherein the dispersing step is effected by compounding at elevated temperatures; and wherein the compounded product is thereafter pelletized.