Polymer blends with improved colorability

• US 6,288,167 B1
• Filed: 05/26/1999
• Issued: 09/11/2001
• Est. Priority Date: 02/01/1995
• Status: Expired due to Term

• Current Assignee: Lanxess Deutschland GmbH (Lanxess AG)
• Original Assignee: Bayer Corporation (Bayer AG)
• Inventors: Peng, Fred Ming-sheng, Chen, Chuan-Ju
• Primary Examiner(s): Cain, Edward J.
• Application Number:
  US09/320,026
• Time in Patent Office: 839 Days
• Field of Search: 525/71, 525/84, 525/85, 525/902
• US Class Current: 525/71
• CPC Class Codes: C08F 285/00 Macromolecular compounds obtained by polymerising monomers on to preformed graft polymers
• CPC Class Codes: C08G 63/48 by unsaturated higher fatty oils or their acids; by resin acids
• CPC Class Codes: C08L 25/12 with unsaturated nitriles
• CPC Class Codes: C08L 51/00 Compositions of graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds for ABS polymers C08L55/02; Compositions of derivatives of such polymers
• CPC Class Codes: Y10S 525/902 Core-shell

Abstract

The present invention is directed to blends of two grafted rubber substrates and a matrix polymer wherein one of the grafted rubber substrates uses a core/shell rubber such as a styrene/butyl acrylate rubber in order to obtain a lower contrast ratio in the blends and better colorability as well as good impact strength.

Claims

1. A polymer blend comprising:

(1) from 30 to 50% by weight based on the total weight of the polymer blend of a first grafted rubber component comprising an acrylate rubber which is grafted with a vinyl aromatic monomer and an unsaturated nitrile monomer and wherein the acrylate rubber is a core/shell rubber comprising a core prepared from a vinyl aromatic monomer and one or more optional comonomers and an acrylate rubber shell wherein the average rubber phase particle size (RPPS) of the core/shell rubber is in the range of from 0.08 to 0.5 microns and wherein the weight of the core is in the range of 5 to 40% by weight of the total weight of the core/shell rubber;

(2) from 15 to 30% by weight based on the total weight of the polymer blend of a second grafted rubber component comprising a rubber substrate selected from the group consisting of diene, ethylene propylene and acrylate rubbers which rubber is grafted with a vinyl aromatic monomer and an unsaturated nitrile monomer wherein the average rubber phase particle size of the rubber substrate is in the range of from 0.3 to 8 microns; and

(3) from 20 to 55% by weight based on the total weight of the polymer blend of a matrix polymer formed from a vinyl aromatic monomer, an unsaturated nitrile monomer and optionally one or more compatible comonomers.

2. A polymer blend as in claim 1 wherein the total amount of rubber in the first and second grafted rubber components is in the range of 10 to 30% based on the total weight of the polymer blend.

3. A polymer blend as in claim 2 wherein the weight of the core in the first grafted rubber component is in the range of 10 to 30% by weight based on the total weight of the core/shell rubber.

4. A polymer blend as in claim 3 wherein the average rubber phase particle size of the core/shell rubber is in the range of 0.1 to 0.3 microns.

5. A polymer blend as in claim 1 wherein the rubber used in the second grafted rubber component is poly(acrylonitrile-butadiene-styrene).

6. A polymer blend as in claim 1 wherein the rubber used in the second grafted rubber component is an ethylene-propylene-diene monomer rubber.

7. A polymer blend as in claim 1 wherein the rubber used in the second grafted rubber component is a butylacrylate rubber.

8. A polymer blend comprising:

(1) from 30 to 50% by weight based on the total weight of the polymer blend of a first grafted rubber component comprising a butyl acrylate rubber which is grafted with styrene and acrylonitrile monomers and wherein the butyl acrylate rubber is a core/shell rubber comprising a core prepared from a styrene monomer and a butyl acrylate rubber shell wherein the average rubber phase particle size (RPPS) of the core/shell rubber is in the range of from 0.1 to 0.3 microns and wherein the weight of the core is in the range of 10 to 30% by weight of the total weight of the core/shell rubber;

(2) from 15 to 30% by weight based on the total weight of the polymer blend of a second grafted rubber component comprising a diene rubber substrate which is grafted with a styrene and acrylonitrile monomer wherein the average rubber phase particle size of the diene rubber substrate is less than 2 microns; and

(3) from 20 to 55% by weight based on the total weight of the polymer blend of a matrix polymer formed from styrene and acrylonitrile monomers.

9. A polymer blend as in claim 8 wherein the total amount of rubber in the first and second grafted rubber components is in the range of 10 to 30% based on the total weight of the polymer blend.

10. A core/shell rubber comprising a styrenic polymer core and a butylacrylate shell which is grafted with a vinyl aromatic monomer and an unsaturated nitrile monomer wherein the average rubber phase particle size (RPPS) of the core/shell rubber is in the range of from 0.08 to 0.5 microns and wherein the weight of the core is in the range of 5 to 40% by weight of the styrenic polymer total weight of the core/shell rubber.