Vapor-permeable, substantially water-impermeable, corrosion- inhibiting composites and methods of making the same
Vapor-permeable, substantially water-impermeable, corrosion-inhibiting composites are disclosed herein. For instance, disclosed herein are composites comprising a first layer comprising a first nonwoven; and a second layer adjacent to and mechanically integrated with the first layer, the second layer comprising a polymer having a melt flow index of about 10 g/10 mins to about 200 g/10 mins, and a corrosion inhibitor, wherein the composite has a moisture vapor transmission rate of from about 25 g/m 2 /day to about 1000 g/m 2 /day when measured at about 23° C. and about 50% relative humidity. Also disclosed herein are methods of making and using the same.
1. A method of producing a composite, the method comprising extruding a corrosion-inhibiting mixture comprising an elastomer having a melt flow index of about 10 g/10 mins to about 300 g/10 mins and a corrosion inhibitor onto a surface of a first nonwoven at an extrusion temperature of from about 170° C. to about 320° C. to form a film layer on the first nonwoven;
wherein the film layer is vapor-permeable and substantially water-impemable, and wherein the combination of the elastomer and the corrosion inhibitor impart corrosion protection and breathability to the composite.
2. The method of claim 1 , further comprising the step of mixing the elastomer with a corrosion inhibitor to product the corrosion-inhibiting mixture.
3. The method of claim 1 , further comprising the step of applying a second nonwoven to the film layer, wherein the film layer is located between the first nonwoven and the second nonwoven.
4. The method of claim 3 , wherein the second nonwoven is added to the film layer while the film layer is molten.
5. The method of claim 3 , further comprising treating a surface of one of more of the first nonwoven and second nonwoven, independently, with a hydrophilic coating or a hydrophobic coating.
6. The method of claim 1 , wherein the elastomer in the film layer comprises a propylene-ethylene copolymer.
7. The method of claim 1 , wherein the corrosion inhibitor is present in an amount of about 0.5% to about 3%, by weight of the corrosion-inhibiting mixture.
8. The method of claim 1 , wherein the corrosion inhibitor comprises morpholine.
9. The method of claim 1 , wherein the composite has a moisture vapor transmission rate of from about 25 g/m 2 /day to about 1000 g/m 2 /day when measured at about 23° C. and about 50 RH %.
10. The method of claim 1 , wherein the first nonwoven comprises a spunbond layer.
11. The method of claim 1 , wherein the elastomer is present in the film layer in an amount of at least about 50% to about 99%, by weight of the film layer.
12. The method of claim 1 , wherein the film layer further comprises a carrier for the corrosion inhibitor.
13. The method of claim 12 , wherein the carrier for the corrosion inhibitor comprises silica.
14. The method of claim 1 , wherein the composite has a hydrostatic head of from about 20 cm to about 200 cm.
15. The method of claim 1 , further comprising subjecting the surface of the first nonwoven to corona treatment or plasma treatment prior to extruding the corrosion- inhibiting mixture onto the surface.
16. The method of claim 1 , further comprising a step of incrementally stretching the composite.
17. The method of claim 16 , wherein the step of incrementally stretching the composite is performed at an elevated temperature from 50° C. to 110° C.
18. The method of claim 1 , wherein the composite has a basis weight from 45 gsm to 290 gsm.
19. The method of claim 1 , wherein the composite has an elongation of at least about 110% and/or at most about 150% in the machine direction as determined according to ASTM D5034.
20. The method of claim 1 , wherein the composite has an elongation of at least about 120% and/or at most about 200% in the cross-machine direction as determined according to ASTM D5034.