WO1997002320B1

WO1997002320B1 - Propylene polymer compositions having improved impact strength

Info

Publication number: WO1997002320B1
Application number: PCT/US1996/011085
Authority: WO
Filing date: 1996-06-28
Publication date: 1997-02-13
Anticipated expiration: 1997-12-30

Abstract

Crystalline propylene polymer compositions having improved impact strength and improved clarity are disclosed. The composition is prepared by melt blending a propylene polymer, e.g., polypropylene, and from about 1 to 35 wt.% of an elastomeric interpolymer of a C4 to C8 isomonoolefin, e.g., isobutylene, and a para-alkystyrene comonomer, e.g., para-methylstyrene. The interpolymer preferably contains a benzylic functional group such as halogen (bromine). The composition may also contain from about 0.5 to 15 wt.% of the amide reaction product of an organic acid-grafted propylene polymer, e.g., maleic anhydride grafted polypropylene, and a polyfunctional primary amine.

Claims

AMENDED CLAIMS

[received by the International Bureau on 15 January 1997 (15.01.97);

original claims 1 and 20 amended; remaining claims unchanged (2 pages)]

1. A solid, high clarity, impact-restant thermoplastic polymer composition comprising a melt-mixed blend of:

a) a crystalline propylene polymer;

b) an interpolymer of a C₄ to C₇ isomonoolefin containing from obout 0.5 to about 20 mole% of copolymerized para- alkylstyrene, said interpolymer present in said composition at a level of from 1 to about 35 wt%, based on the polymer content of said composition.

2. The composition of claim 1 wherein said propylene polymer is selected from the group consisting of polypropylene and copolymers of propylene with up to about 20 wt% of a C₂ or C₄ - C₆ alpha-monoolefin.

3. The composition of claim 1 wherein said isomonoolefin is isobutylene and said para- alkylstyrene is para-methylstyrene.

4. The composition of claim 1 wherein said interpolymer is present in said composition at a level of from about 5 to about 30 wt%.

5. The composition of claim 1 wherein said interpolymer comprises a polymer of isobutylene containing the following aromatic monomer units randomly spaced along the polymer chain:

grafted along the polymer chain, said unsaturated compound selected from the group consisting of en unsaturated carboxylic acid, an unsaturated carboxylic acid anhydride and mixtures thereof; and

(ii) a polyfunctional primary amine having one primary amine group and at least one hydroxy, secondary amine or tertiary amine group.

20. A shaped article prepared by melt mixing the composition of claim 1, and forming and cooling the molten mixture into the shape of the article.

STATEMENT UNDER ARTICLE 19

The prior art shows blends of polyolefin with a polyolefingrafted (for compatibilization purposes) isoolefin-alkylstyrene copolymer; and dynamically vulcanized polyolefin/functionalized isoolefin-alkylstyrene copolymers. In contrast, the present invention (claims 1-9, 14-18 and 20) is a melt-mixed blend of crystalline polypropylene and isoolefin-alkylstyrene copolymer which has surprisingly improved impact strength, high clarity and processability not present or suggested by the prior art. The melt-mixed composition has a morphology and properties which are different from the prior art dynamically vulcanized compositions or compositions which employ a compatibilized (polyolefin-grafted) component

With respect to the embodiment of the invention of claims 10-13 and 19, the prior art teaches dynamically vulcanized polyolefin/functionallzed isoolefin-alkylstyrene with "any optional polymers"; and blends of polyolefin and rubber with compatibilizing polyolefin-grafted isoolefin-alkylstyrene. There is no teaching or suggestion in the prior art to blend crystalline polypropylene, isoolefin-alkylstyrene copolymer, and amine-modified, unsaturated-carboxylic-acid-grafted polypropylene as a third component with the result that the ternary blend has improved impact strength and good clarity.