Polyolefin-based elastic film structures, laminates and methods thereof

Patent metadata

Field	Value
Publication number	US-10967619-B2
Application number	US-201515509224-A
Country	US
Kind code	B2
Filing date	Sep 21, 2015
Priority date	Sep 25, 2014
Publication date	Apr 6, 2021
Grant date	Apr 6, 2021

Abstract

A stretch-modified elastomeric multilayer film comprising a core layer comprising a first ethylene-α-olefin block copolymer, wherein the first ethylene-α-olefin block copolymer comprises at least 50 mol. % ethylene, has a melt index (I2) from 0.5 g/10 min to 5 g/10 min, and has a density of 0.850 g/cc to 0.890 g/cc, and at least one outer layer independently comprising a second ethylene-α-olefin block copolymer and from 2.5 to 30 wt. % of an antiblock agent, wherein the second ethylene-α-olefin block copolymer comprises at least 50 mol. % ethylene, has a melt index (I2) from 0.5 g/10 min to 25 g/10 min, and has a density of 0.850 g/cc to 0.890 g/cc, wherein the density of the first ethylene-α-olefin block copolymer is equal to or greater than the density of the second ethylene-α-olefin block copolymer.

First claim

What is claimed is:

1. A stretch-modified elastomeric multilayer film comprising:
a core layer comprising a first ethylene-α-olefin block copolymer, wherein the first ethylene-α-olefin block copolymer comprises at least 50 mol. % ethylene, has a melt index (I 2 ) from 0.5 g/10 min to 5 g/10 min, and has a density of 0.850 g/cc to 0.890 g/cc; and
at least one outer layer independently comprising a second ethylene-α-olefin block copolymer and from 2.5 to 30 wt. % of an antiblock agent, wherein the second ethylene-α-olefin block copolymer comprises at least 50 mol. % ethylene, has a melt index (I 2 ) from 0.5 g/10 min to 25 g/10 min, and has a density of 0.850 g/cc to 0.890 g/cc;
wherein the density of the first ethylene-α-olefin block copolymer is equal to or greater than the density of the second ethylene-α-olefin block copolymer.

2. The film of claim 1 , wherein the first ethylene α-olefin block copolymer is different from the second ethylene-α-olefin block copolymer.

3. The film of claim 1 , wherein the film further comprises a slip agent in the at least one outer layer, and optionally, in the core layer.

4. The film of claim 1 , wherein the melt index of the first ethylene-α-olefin block copolymer is different than the melt index of the second ethylene-α-olefin block copolymer.

5. The film of claim 1 , wherein the film exhibits a reduction in permanent set as compared to an identical film that has not been stretch-modified.

6. The film of claim 1 , wherein the film exhibits a first cycle retraction force that is at least 25% greater than a first cycle retraction force of an identical film that has not been stretch-modified.

7. The film of claim 1 , wherein the film is a blown film or a cast film.

8. A laminate comprising the stretch-modified elastomeric multilayer film of claim 1 .

9. The laminate of claim 8 , further comprising at least one substrate laminated to a side of the film.

10. A process for manufacturing a stretch-modified elastomeric multilayer film, the process comprising:
providing the multilayer film of claim 1 ;
performing a first stretch of the multilayer film in at least one direction at a draw ratio of at least 1.9 to form a stretch-modified multilayer film; and
substantially relaxing the stretch-modified multilayer film in the at least one direction.

11. The process of claim 10 , wherein the process further comprises laminating the stretch-modified multilayer film to at least one substrate to form a laminate.

12. The process of claim 11 , wherein the substrate is a nonwoven.

13. The process of claim 11 , wherein the substrate is an elastic nonwoven.

14. The process of claim 13 , wherein the elastic nonwoven has a corrugated shape.

15. The process of claim 11 , wherein the laminate undergoes a second stretch in at least one direction to a draw ratio of 3.6 or less of its pre-second stretch length.

16. The process of claim 11 , wherein the laminate does not undergo a second stretch.

Assignees

• Dow Global Technologies Llc

Inventors

• Chang Andy C
• Degroot Jacquelyn A
• Brown Kate R
• Stoiljkovic Aleksandar
• Claasen Gert J
• Bonavoglia Barbara
• Ruiz Carlos E

Classifications

• B32B7/02

  Physical, chemical or physicochemical properties · CPC title

• B32B2307/514

  Oriented · CPC title

• B32B38/0012

  Mechanical treatment, e.g. roughening, deforming, stretching · CPC title

• B32B27/32 Primary

  comprising polyolefins {(comprising vinyl (co)polymers or acrylic (co)polymers B32B27/30)} · CPC title

• B32B27/18

  characterised by the use of special additives · CPC title