Fluid repellent microporous materials

• US 7,247,369 B2
• Filed: 02/03/2005
• Issued: 07/24/2007
• Est. Priority Date: 05/29/2002
• Status: Expired due to Fees

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Jariwala, Chetan P., Mrozinski, James S.
• Primary Examiner(s): Chang; Victor S.
• Application Number:
  US11/050,507
• Publication Number:
  US 20050129922A1
• Time in Patent Office: 901 Days
• Field of Search: 428/304.4, 428/315.5, 428/315.9, 428/221, 428/357, 428/364, 428/365, 428/395, 524/95, 524/425, 524/401, 524/445, 524/449, 524/319, 524/462, 424/402, 525/165, 525/178, 525/199, 525/200
• US Class Current: 428/304.4
• CPC Class Codes: B29C 55/005 characterised by the choice of materials
• CPC Class Codes: B29K 2105/04 cellular or porous
• CPC Class Codes: B29K 2105/16 Fillers
• CPC Class Codes: B32B 5/18 characterised by features of a layer of foamed material
• CPC Class Codes: Y10T 428/249921 Web or sheet containing structurally defined element or component
• CPC Class Codes: Y10T 428/249953 Composite having voids in a component [e.g., porous, cellular, etc.]
• CPC Class Codes: Y10T 428/249978 Voids specified as micro
• CPC Class Codes: Y10T 428/24998 Composite has more than two layers
• CPC Class Codes: Y10T 428/29 Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
• CPC Class Codes: Y10T 428/2913 Rod, strand, filament or fiber
• CPC Class Codes: Y10T 428/2915 including textile, cloth or fabric
• CPC Class Codes: Y10T 428/2969 Polyamide, polyimide or polyester

Abstract

Microporous articles formed by thermally induced phase separation from a diluent in combination with a thermoplastic polymer and a fluorochemical additive providing novel fluid repellent articles. Such articles are useful in clothing, barrier membranes, optical films in electronic devices (such as light reflective and dispersive films), and protective garments.

Claims

1. A microporous article comprising:

(a) a crystallizable olefin polymer component; and

(b) a fluorochemical additive comprising a compound the formula;

2. The microporous article of claim 1 further comprising a diluent component, said diluent component being miscible with the polymer component at a temperature above the liquid-solid phase separation temperature and able to phase separate from the polymer component through crystallization separation upon cooling below the liquid-solid phase separation temperature.

3. The microporous article of claim 2 comprising:

(a) about 40 to 80 parts by weight of said crystallizable olefin polymer component;

(b) about 20 to 60 parts by weight of said diluent component; and

(c) at least about 0.5 parts by weight of said fluorochemical compound.

4. The article of claim 2 wherein said diluent is selected from the group consisting of alkyl phthalates, mineral oil;

mineral spirits;

petroleum jelly, waxes and mixtures and blends thereof.

5. The article of claim 2 comprising a first phase of polymer spherulities inconnected with polymer fibrils creating a network of interconnected micropores, and a second phase comprising the diluent component and fluorochemical additive at least partially coating said spherulites and fibrils.

6. The microporous article of claim 2 wherein said polymer and said diluent are selected from the group consisting of polypropylene with mineral oil, dioctyl phthalate, petroleum jelly, wax or mineral spirits;

polypropylene-polyethylene copolymer with mineral oil;

polyethylene with mineral oil or mineral spirits; and

mixtures and blends thereof.

7. The microporous article of claim 1 further comprising an inorganic filler.

8. The microporous article of claim 7 wherein said inorganic filler is selected from the group consisting of alkali- or alkaline earth metal carbonates and sulfates.

9. The microporous article of claim 3 comprising 35 to 60 parts by weight of diluent component.

10. The microporous article of claim 3 comprising 65 to 80 parts by weight of polymer component.

11. The microporous article of claim 3 comprising 1 to 10 parts by weight of fluorochemical additive.

12. The microporous article of claim 3, further comprising 0.05 to 5 parts by weight of a nucleating agent.

13. A method of making a microporous article of claim 1, comprising:

(a) melt blending to form a solution comprising about 40 to 80 parts by weight of a polymer component, about 20 to 60 parts by weight of an diluent component, said diluent component being miscible with the polymer component at a temperature above the liquid-solid phase separation temperature; and

at least about 0.5 parts by weight of said fluorochemical;

(b) forming a shaped article of the melt blended solution;

(c) cooling said shaped article to a temperature below the liquid-solid phase separation temperature at which phase transition occurs between the diluent component and the polymer component through crystallization precipitation of the polymer component to form a network of polymer domains;

(d) creating porosity by orienting said article at least in one direction to separate adjacent crystallized polymer domains from one another;

to provide a network of interconnected micropores therebetween.

14. The method of claim 13 wherein said article is a film.

15. The method of claim 13 further comprising the step of bonding said microporous film to an additional layer to produce a multilayer article.

16. The method of claim 15 wherein said additional layer is selected from non-woven fabrics scrims or webs, woven fabrics or scrims, porous film, and non-porous film.

17. The method of claim 15 where said bonding step is selected from heat-sealing, ultrasonic welding, heat and/or pressure lamination or adhesive bonding.

18. The method of claim 17 wherein said step of lamination comprises pressing the microporous film and said additional layer together in a nip and heating sufficiently to soften the microporous article and/or additional layer.

19. A method for preparing a multilayer microporous film according to claim 13 wherein said forming step further comprises simultaneously coextruding a melt-processible organic polymeric material to form a unified construction of at least 2 layers of organic polymeric material, wherein at least one layer comprises a microporous film layer.

20. Method of claim 13 wherein the polymer component is a polyolefin, a polyolefin copolymer, a polyolefin blend or a mixture thereof.

21. Method of claim 20, wherein the polyolefin is polypropylene, high density polyethylene, or copolymers of propylene and ethylene.

22. The method of claim 13 wherein the fluorochemical additive comprises about 1 to 10 weight percent of the article.