Polypropylene resin suitable for soft nonwoven applications

Patent metadata

Field	Value
Publication number	US-9683096-B2
Application number	US-85949910-A
Country	US
Kind code	B2
Filing date	Aug 19, 2010
Priority date	Aug 19, 2010
Publication date	Jun 20, 2017
Grant date	Jun 20, 2017

Abstract

A polypropylene impact copolymer is disclosed. The propylene impact copolymer composition comprises from 60 to 90 percent by weight of the impact copolymer composition of a matrix phase, which can be a homopolymer polypropylene or random polypropylene copolymer having from 0.1 to 7 mol percent of units derived from ethylene or C 4 -C 10 alpha olefins. The propylene impact copolymer composition also comprises from 10 to 40 percent by weight of the impact copolymer composition of a dispersed phase, which comprises a propylene/alpha-olefin copolymer having from 6 to 40 mol percent of units derived from ethylene or C 4 -C 10 alpha olefins, wherein the dispersed phase has a comonomer content which is greater than the comonomer content in the matrix phase. The propylene impact copolymer composition is further characterized by having the ratio of the dispersed phase intrinsic viscosity (IV) to the matrix phase IV being 0.95 or less. The polypropylene impact copolymers of the present invention are well suited for making spunbond fibers which can be used to make nonwoven fabrics having good haptics.

First claim

What is claimed is:

1. A polypropylene impact copolymer composition comprising:
a) from 60 to 90 percent by weight of the impact copolymer composition of a matrix phase, said matrix phase comprising a homopolymer polypropylene or random polypropylene copolymer having from 0.1 to 7 mol percent of units derived from ethylene or C 4 -C 10 alpha olefins; and
b) from 10 to 40 percent by weight of the impact copolymer composition of a dispersed phase, said dispersed phase comprising a propylene/alpha-olefin copolymer having from 6 to 40 mol percent of units derived from ethylene or C 4 -C 10 alpha olefins, wherein the dispersed phase has a comonomer content which is greater than the comonomer content in the matrix phase, wherein the impact copolymer is characterized by having a beta/alpha (β/α) ratio of 0.9 or less,
with

β
/
α

=

(

MFR
1

/

MFR
2

)

0.213

-
1

(

Fc
/
100

)

+
1

where MFR 1 is the first reactor (matrix phase only), MFR 2 is the second reactor (overall impact copolymer), and F c is the percent by weight of the dispersed phase in the impact copolymer composition,
the polypropylene impact copolymer composition further characterized as having a melt flow rate in the range of from 25 to 65 g/10 min.

2. The polypropylene impact copolymer of claim 1 wherein the matrix phase comprises from 65 to 85 percent by weight of the impact copolymer composition.

3. The polypropylene impact copolymer of claim 1 wherein the dispersed phase is partially miscible within the matrix phase.

4. The polypropylene impact copolymer of claim 1 wherein the random polypropylene copolymer has from 0.5 to 3 mol percent of units derived from ethylene or C 4 -C 10 alpha olefins.

5. The polypropylene impact copolymer of claim 1 wherein the dispersed phase comprises from 15 to 35 percent by weight of the total impact copolymer.

6. The polypropylene impact copolymer of claim 1 wherein the propylene/alpha-olefin copolymer has an alpha-olefin content ranging from 8 to 18 mol percent.

7. The polypropylene impact copolymer of claim 1 wherein the propylene/alpha-olefin copolymer is a propylene/ethylene copolymer.

8. The polypropylene impact copolymer of claim 1 wherein the impact copolymer has been peroxide cracked.

9. The polypropylene impact copolymer of claim 1 wherein the dispersed phase has a comonomer content which is at least 10 percent (absolute) greater than the comonomer content in the matrix phase.

10. The polypropylene impact copolymer of claim 1 further comprising at least one slip additive.

11. The polypropylene impact copolymer of claim 10 wherein the slip additive is erucamide and is present in an amount of from 100 ppm to 2000 ppm.

12. The polypropylene impact copolymer of claim 11 wherein the erucamide is present in an amount of from 250 ppm to 750 ppm.

13. A composition comprising at least one slip agent and a polypropylene impact copolymer composition comprising:
a) from 65 to 80 percent by weight of the impact copolymer composition of a matrix phase, said matrix phase comprising a random polypropylene copolymer having from 0.5 to 3 mol percent of units derived from ethylene or butylene; and
b) from 20 to 35 percent by weight of the impact copolymer composition of a dispersed phase, said dispersed phase comprising a propylene/alpha-olefin copolymer having from 8 to 18 mol percent of units derived from ethylene or butylene, wherein the dispersed phase has a comonomer content which is greater than the comonomer content in the matrix phase;
wherein the impact copolymer is characterized by having a beta/alpha (β/α) ratio of 0.9 or less,
with

β
/
α

=

(

MFR
1

/

MFR
2

)

0.213

-
1

(

Fc
/
100

)

+
1

where MFR 1 is the first reactor (matrix phase only), MFR 2 is the second reactor (overall impact copolymer), and F c is the percent by weight of the dispersed phase in the impact copolymer composition,
the polypropylene impact copolymer composition further characterized as having a melt flow rate in the range of from 25 to 65 g/10 min.

Assignees

• Kaarto John
• Crown Alechia
• Tau Li-Min
• Claasen Gert J
• Braskem America Inc

Inventors

• Kaarto John
• Crown Alechia
• Tau Li-Min
• Claasen Gert J

Classifications

• C08L2205/02

  containing two or more polymers of the same C08L -group · CPC title

• C08L2207/02

  Heterophasic composition · CPC title

• C08K5/20

  Carboxylic acid amides · CPC title

• C08L23/14

  Copolymers of propene (C08L23/16 takes precedence) · CPC title

• C08L23/10 Primary

  Homopolymers or copolymers of propene · CPC title