Meltblown nonwoven fabrics, and composites thereof

Patent metadata

Field	Value
Publication number	US-11939712-B2
Application number	US-202017595479-A
Country	US
Kind code	B2
Filing date	Jul 20, 2020
Priority date	Jul 26, 2019
Publication date	Mar 26, 2024
Grant date	Mar 26, 2024

Abstract

A meltblown nonwoven formed from a bicomponent fiber, wherein: the bicomponent fiber has a first region and a second region, the first region is formed from a first composition comprising at least 75 wt. % of a polypropylene; the second region is formed from a second composition comprising at least 75 wt. % of an ethylene/alpha-olefin interpolymer.

First claim

We claim:

1. A meltblown nonwoven formed from a bicomponent fiber, wherein:
the bicomponent fiber has a first region and a second region,
the first region is formed from a first composition comprising at least 75 wt. % of a polypropylene;
the second region is formed from a second composition comprising at least 75 wt. % of an ethylene/alpha-olefin interpolymer having
a density of from 0.911 to 0.950 g/cc,
a Brookfield viscosity at 177° C. from 5,000 cP to 40,000 cP, and
a molecular weight distribution (Mw,cc/Mn,cc) of 1.8 to 3.5,
a highest DSC temperature crystallization peak, Tc, from 80° C. to 110° C.;
the ethylene/α-olefin interpolymer has a temperature differential between a highest DSC temperature melting peak (Tm) and a highest DSC temperature crystallization peak (Tc), (ΔTm-Tc), of less than 16° C.; and
the bicomponent fiber has a shear viscosity ratio of the first composition to the second composition of less than 2.0.

2. The meltblown nonwoven of claim 1 , wherein the ethylene/alpha-olefin interpolymer has an Mz,cc/Mn,cc of less than 3.5.

3. The meltblown nonwoven of claim 1 , wherein the ethylene/alpha-olefin interpolymer has a weight fraction (w) of molecular weight greater than 10 5 g/mole, based on the total weight of interpolymer, as determined by conventional gel permeation chromatography, of less than 2.5%, or alternatively, less than 1.0%.

4. The meltblown nonwoven of claim 1 , wherein the ethylene/alpha-olefin interpolymer has a comonomer distribution breadth index of greater than 50%.

5. The meltblown nonwoven of claim 1 , wherein the bicomponent fiber has a sheath/core structure.

6. The meltblown nonwoven of claim 5 , wherein the first region is a core region and the second region is a sheath region.

7. The meltblown nonwoven of claim 1 , wherein the meltblown nonwoven exhibits an air permeability of less than 500 l/m 2 /s at 20 gsm.

8. A composite structure comprising the meltblown nonwoven of claim 1 .

9. The composite structure of claim 8 , wherein the composite structure further comprises one or more spunbond nonwovens.

10. A composite structure having a SaMbSc configuration, wherein S is a spunbond nonwoven, M is a meltblown nonwoven of claim 1 , and a, b, and c are the number of layers and are independent integers ranging from 1 to 5.

11. The composite structure of claim 10 , wherein the spunbond nonwoven is formed from bicomponent fibers having a sheath/core structure, wherein the sheath comprises polyethylene and the core comprises polypropylene.

12. The composite structure of claim 10 , wherein the spunbond nonwoven is formed from monocomponent fibers, wherein the monocomponent fibers comprise polyethylene.

13. The meltblown nonwoven of claim 1 , wherein the bicomponent fiber has an average diameter less than 10 microns.

Assignees

• Dow Global Technologies Llc

Inventors

• Stoiljkovic Aleksandar
• Alvarez Eduardo
• Lin Yijian

Classifications

• D04H3/018 Primary

  characterised by the shape · CPC title

• A61F13/15577

  Apparatus or processes for manufacturing · CPC title

• D04H1/4291 Primary

  Olefin series · CPC title

• D04H1/4391

  characterised by the shape of the fibres · CPC title

• D04H1/724

  forming webs during fibre formation, e.g. flash-spinning · CPC title