Polyolefin based elastic compositions, methods of manufacturing thereof and articles comprising the same

Patent metadata

Field	Value
Publication number	US-11230641-B2
Application number	US-201615747917-A
Country	US
Kind code	B2
Filing date	Jul 21, 2016
Priority date	Jul 27, 2015
Publication date	Jan 25, 2022
Grant date	Jan 25, 2022

Abstract

Disclosed herein is a film comprising a polymer blend, the polymer blend comprising a first polyolefin elastomer having a weight average molecular weight of 120,000 to 350,000 grams per mole; and a second polyolefin elastomer having a weight average molecular weight of 15,000 to 75,000 grams per mole; wherein the overall melt index of the polymer blend is less than 8 g/10 minutes when measured as per ASTM D1238 at 2.16 kilograms at 190° C. Disclosed herein too is a method of manufacturing a film comprising blending a first polyolefin elastomer having a weight average molecular weight of 120,000 to 350,000 grams per mole; and a second polyolefin elastomer having a weight average molecular weight of 15,000 to 75,000 grams per mole to form a polymer blend; wherein the overall melt index of the polymer blend is less than 8 g/10 minutes when measured as per ASTM D1238 at 2.16 kilograms at 190° C.; and forming the polymer blend into a film.

First claim

What is claimed is:

1. A polymer blend comprising:
a first polyolefin elastomer having a weight average molecular weight of 120,000 to 350,000 grams per mole; and
a second polyolefin elastomer having a weight average molecular weight of 15,000 to 75,000 grams per mole; wherein the overall melt index of the polymer blend is less than 8 g/10 minutes when measured as per ASTM D1238 at 2.16 kilograms at 190° C.; wherein the first polyolefin elastomer is present in the blend in an amount of greater than 50 wt %, based on the total weight of the blend; wherein the first polyolefin elastomer and the second polyolefin elastomer each have a density in the range of 0.857 to 0.89 g/cm 3 and are each a linear olefin block copolymer which does not include styrene monomer; wherein the polymer blend has a molecular weight distribution Mw/Mn that is greater than 2.5.

2. The blend of claim 1 , wherein the first polyolefin elastomer and the second polyolefin elastomer are both propylene-based elastomers.

3. The blend of claim 1 , wherein the olefin block copolymers are propylene/a-olefin block copolymers.

4. The blend of claim 1 , wherein each olefin block copolymer is an ethylene/α-olefin block copolymer.

5. An article comprising the blend of claim 1 , wherein the article is a film.

6. The article of claim 5 , wherein the film upon being stretch modified exhibits a 2.5 to 10% reduction in permanent set when compared with an identical film that has not been stretch modified.

7. The article of claim 5 , wherein the film upon being stretch modified exhibits a first cycle force that is at least 25% greater than a first cycle retraction force of an identical film that has not been stretch modified.

8. The article of claim 5 , wherein the article is a multilayered laminate that comprises the film with at least one non-woven layer disposed on a surface of the film.

9. A method of manufacturing the film of claim 5 comprising:
blending the first polyolefin elastomer having a weight average molecular weight of 120,000 to 350,000 grams per mole; and the second polyolefin elastomer having a weight average molecular weight of 15,000 to 75,000 grams per mole to form the polymer blend; wherein the overall melt index of the polymer blend is less than 8 g/10 minutes when measured as per ASTM D1238 at 2.16 kilograms at 190° C.; wherein the polymer blend has a molecular weight distribution Mw/Mn that is greater than 2.5; and
forming the polymer blend into the film.

10. The method of claim 9 , wherein the forming comprises extrusion, molding, casting, or a combination thereof.

11. The method of claim 9 , further comprising performing a first stretch of the film in at least one direction to form a stretch-modified film and substantially relaxing the stretch-modified multilayer film in the at least one direction.

12. The method of claim 11 , further comprising laminating the film to a non-woven layer to form a laminate.

13. The method of claim 12 , further comprising laminating the stretch-modified film to a non-woven layer to form a laminate.

Assignees

• Dow Global Technologies Llc

Inventors

• Degroot Jacquelyn A
• Gardarsson Thor E
• Madenjian Lisa S

Classifications

• C08L23/0815

  with aliphatic 1-olefins containing one carbon-to-carbon double bond · CPC title

• B32B2307/738

  Thermoformability · CPC title

• B32B27/28

  comprising synthetic resins not wholly covered by any one of the sub-groups {B32B27/30 - B32B27/42} · CPC title

• B32B2307/732

  Dimensional properties · CPC title

• B32B2307/514

  Oriented · CPC title