Moisture and gas permeable non-porous ionomeric films
View Patent ↗Moisture and gas permeable ionomeric films are described. The films described herein are obtained from blends of ionomers with an organic acid salt in the amount of at least about 5 wt %, and have MVTR greater than films obtained from conventional ionomers. Particularly preferred are the potassium salts of stearic, oleic, isostearic, and isooleic acids. Films comprising a liquid-absorbent ionomer film layer and an impermeable layer are provided. The films are suitable for preparation of tubular casings and shrinkbags, in particular, casings for smoked foodstuffs.
1. A film having an oxygen transmission rate (OTR) of at least about 100 cc·mil/m 2 ·D, and a moisture vapor transmission rate (MVTR) of at least about 200 g·mil/m 2 ·D, wherein the film comprises a blend of: (i) an ethylene acid copolymer ionomer present in an amount of from about 50 wt % to about 95 wt %; and, (ii) at least about 5 wt % of an organic acid salt.
2. The film of claim 1 wherein the organic acid salt is present in an amount of at least about 10 wt %.
3. The film of claim 2 wherein the organic acid salt is present in an amount of at least about 20 wt %.
4. The film of claim 3 wherein the organic acid salt is present in an amount of at least about 30 wt %.
5. The film of claim 4 wherein the organic acid salt is present in an amount of up to about 50 wt %.
6. The film of claim 5 wherein the organic acid salt has no more than 36 carbon atoms.
7. The film of claim 6 wherein the organic acid salt has from 12 to 36 carbon atoms.
8. The film of claim 7 wherein: (1) the salt is of an acid selected from the group consisting of: caproic, caprylic, capric lauric, myristic, palmitic, stearic, oleic, linoleic, erucic and behenic acids; and isomers thereof; and (2) the counterion is at least one metal ion derived from metals in the group consisting of alkali metals, transition metals, and alkaline earth metals.
9. The film of claim 8 wherein the acid is selected from the group consisting of: isomers of caproic, caprylic, capric lauric, myristic, palmitic, stearic, oleic, linoleic, erucic and behenic acids and the metal counterion is potassium ion.
10. The film of claim 9 wherein the acid is selected from the group consisting of: isomers of stearic acid and oleic acid.
11. The film of claim 10 wherein the acid is selected from the group consisting of: branched isomers of stearic acid and oleic acid.
12. The film of claim 11 wherein the acid is isostearic acid.
13. The film of claim 12 wherein the film has an OTR of at least about 500.
14. The film of claim 13 having an OTR of at least about 1000.
15. The film of claim 14 having an OTR of at least about from about 3000 to about 25,000.
16. The film of claim 12 having an MVTR of at least about 500.
17. The film of claim 16 having an MVTR of at least about 750.
18. The film of claim 17 having an MVTR of at least about 1000.
19. The film of claim 18 having an MVTR of at least about 1200.
20. The film of claim 19 having an MVTR of at least about 1500.
21. The film of claim 20 having an MVTR of at least about 2500.
22. The film of claim 21 having an MVTR of at least about 10,000.
23. The film of claim 22 having an MVTR of from about 10,000 to about 20,000.
24. A laminate film comprising a liquid absorptive inner layer and an impermeable outer layer wherein: the absorptive layer comprises the film of claim 20 and the outer impermeable film layer is a single film layer, or a laminate or multilayer film comprising: (a) at least one polymer layer comprising a polymer selected from polymers in the group consisting of: polyamides or mixtures thereof, ethylene vinyl alcohol copolymers; polyvinylidene chloride; polyolefins; or mixtures of any of these; and (b) optionally at least one tie layer.