Ionomer/polyamide blends with improved flow and impact properties

• US 6,756,443 B2
• Filed: 01/25/2002
• Issued: 06/29/2004
• Est. Priority Date: 01/25/2002
• Status: Expired due to Term

• Current Assignee: Dow Global Technologies LLC (Dow, Inc.)
• Original Assignee: E. I. du Pont de Nemours and Company (Corteva, Inc.)
• Inventors: Feinberg, Stewart Carl
• Primary Examiner(s): MULLIS, JEFFREY C
• Application Number:
  US10/057,145
• Publication Number:
  US 20030149175A1
• Time in Patent Office: 886 Days
• Field of Search: 525/66, 525/191, 525/193, 525/195, 525/201, 525/240, 525/221, 525/419
• US Class Current: 525/66
• CPC Class Codes: C08L 23/00 Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
• CPC Class Codes: C08L 23/08 Copolymers of ethene C08L23/16 takes precedence
• CPC Class Codes: C08L 23/0815 Copolymers of ethene with aliphatic 1-olefins
• CPC Class Codes: C08L 23/0869 Acids or derivatives thereof
• CPC Class Codes: C08L 23/0876 Neutralised polymers, i.e. ionomers
• CPC Class Codes: C08L 23/16 Elastomeric ethene-propene or ethene-propene-diene copolymers, e.g. EPR and EPDM rubbers
• CPC Class Codes: C08L 2666/02 Organic macromolecular compounds, natural resins, waxes or and bituminous materials
• CPC Class Codes: C08L 2666/06 Homopolymers or copolymers of unsaturated hydrocarbons; Derivatives thereof
• CPC Class Codes: C08L 2666/24 Graft or block copolymers according to groups C08L51/00, C08L53/00 or C08L55/02; Derivatives thereof
• 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: C08L 51/06 grafted on to homopolymers or copolymers of aliphatic hydrocarbons containing only one carbon-to-carbon double bond
• CPC Class Codes: C08L 77/00 Compositions of polyamides obtained by reactions forming a carboxylic amide link in the main chain of polyhydrazides C08L79/06; of polyamideimides or polyamide acids C08L79/08; Compositions of derivatives of such polymers
• CPC Class Codes: C08L 77/02 Polyamides derived from omega-amino carboxylic acids or from lactams thereof C08L77/10 takes precedence
• CPC Class Codes: C08L 77/06 Polyamides derived from polyamines and polycarboxylic acids C08L77/10 takes precedence

Abstract

An ionomer/polyamide blend with improved flow (e.g., lower viscosity) can be achieved while simultaneously maintaining or improving physical properties such as low temperature Izod impact resistance by the addition of low molecular weight ethylene/acrylic acid copolymer (e.g., so-called acid wax polymer derived from copolymerizing at least 5 weight percent and preferably greater than 9 weight percent acrylic acid and/or methacrylic acid with ethylene and having a melt index, ASTM D1238, preferably greater than 900 dg/min and most preferably greater than 5,000 dg/min). Optionally, the blends can further contain additives such as very low density polyethylene (VLDPE), ethylene propylene elastomer (EPR), ethylene propylene diene monomer elastomer (EPDM), corresponding maleic anhydride grafted elastomers (MAN-g-VLDPE; MAN-g-EPR; and MAN-g-EPDM), or mixtures thereof. The blends exhibiting improved flow characteristics according to the instant invention are particularly useful in the manufacture of automotive parts, panels and the like having a “class A” surface.

Claims

1. An ionomer/polyamide alloy blend having improved flow properties comprising;

an ionomer/polyamide alloy consisting of from 40 to 60 parts by weight ionomer phase and from 60 to 40 parts by weight continuous or co-continuous semicrystalline polyamide phase and for every one hundred parts by weight of ionomer/polyamide alloy blend;

(i) from one to twenty parts by weight low molecular weight copolymer of ethylene and at least one other comonomer selected from the group consisting of acrylic acid, methacrylic acid and mixtures thereof, wherein said low molecular weight copolymer has a melt index (ASTM D1238) of greater than 350 dg/min and an acrylic acid and methacrylic acid combined comonomer content of at least 5 weight percent; and

optionally

(ii) up to twenty parts per weight of one or more additives selected from the group consisting of very low density polyethylene (VLDPE), maleic anhydride grafted VLDPE, ethylene propylene (EPR) rubber, maleic anhydride grafted EPR, ethylene propylene diene monomer (EPDM) rubber, maleic anhydride grafted EPDM and mixtures thereof.

2. An ionomer/polyamide alloy blend of claim 1 wherein said low molecular weight copolymer of ethylene and at least one other comonomer has a melt index of at least 900 dg/min.

3. An ionomer/polyamide alloy blend of claim 1 wherein said very molecular weight copolymer of ethylene and at least one other comonomer has an acrylic acid and methacrylic acid combined comonomer content of at least 9 weight percent.

4. A method of reducing the viscosity of an ionomer/polyamide alloy blend without significantly degrading low temperature impact resistance comprising the steps of blending for every one hundred parts by weight of ionomer/polyamide alloy blend

(i) from one to twenty parts by weight low molecular weight copolymer of ethylene and at least one other comonomer selected from the group consisting of acrylic acid, methacrylic acid and mixtures thereof, wherein said low molecular weight copolymer has a melt index (ASTM D1238) of greater than 350 dg/min and an acrylic acid and methacrylic acid combined comonomer content of at least 5 weight percent; and optionally

(ii) up to twenty parts per weight of one or more additives selected from the group consisting of very low density polyethylene (VLDPE), maleic anhydride grafted VLDPE, ethylene propylene (EPR) rubber, maleic anhydride grafted EPR, ethylene propylene diene monomer rubber (EPDM), maleic anhydride grafted EPDM, and mixtures thereof to produce a blend of claim 1.

5. A method of claim 4 wherein said low molecular weight copolymer of ethylene and at least one other comonomer has a melt index of at least 900 dg/min.

6. A method of claim 4 wherein said low molecular weight copolymer of ethylene and at least one other comonomer has an acrylic acid and methacrylic acid combined comonomer content of at least 9 weight percent.

7. A metallic pigmented ionomer/polyamide alloy blend having improved impact properties comprising for every one hundred parts by weight of ionomer/polyamide alloy blend:

from 2.5 to twenty parts per weight of one or more additives selected from the group consisting of very low density polyethylene (VLDPE), maleic anhydride grafted VLDPE, ethylene propylene (EPR) rubber, maleic anhydride grafted EPR, ethylene propylene diene monomer (EPDM) rubber, maleic anhydride grafted EPDM and mixtures thereof.

8. A metallic pigmented ionomer/polyamide alloy blend of claim 7 wherein said additive is a maleic anhydride grafted EPDM.

9. A method of restoring impact resistance of a metallic pigmented ionomer/polyamide alloy blend comprising the step of blending for every one hundred parts by weight of a metallic pigmented ionomer/polyamide alloy blend from 2.5 to twenty parts per weight of one or more additives selected from the group consisting of very low density polyethylene (VLDPE), maleic anhydride grafted VLDPE, ethylene propylene (EPR) rubber, maleic anhydride grafted EPR, ethylene propylene diene monomer rubber (EPDM), maleic anhydride grafted EPDM, and mixtures thereof.

10. A method of claim 9 wherein said additive is a maleic anhydride grafted EPDM.