Extrusion coated barrier film

Abstract

The present development is an extrusion coated barrier film with perforated holes for breathability and a moisture vapor barrier. More specifically, the coated barrier material comprises biaxially oriented nylon film extrusion coated with a blend of an acid copolymer and at least one block copolymer material made up of rigid polyamide blocks and soft polyether blocks. The extrusion coated barrier film can be thermally laminated to expanded polystyrene (EPS) foam boards, which can be used as housewrap, roofing underlayment, or in other construction materials.

Claims

1. A barrier film comprising a biaxially oriented nylon film extrusion coated with a polymer blend consisting essentially of ethylene-methylacrylate copolymer and at least one block copolymer, wherein the at least one block copolymer comprises rigid polyamide blocks and soft polyether blocks.

2. The barrier film of claim 1 wherein the nylon film is a 30-gauge to 60-gauge biaxially oriented film.

3. The nylon film of claim 2 wherein the nylon film has a weight of from about 13.22 grams per square meter to about 14.62 grams per square meter.

4. The nylon film of claim 3 wherein the nylon film has a weight of from about 13.88 grams per square meter to about 14.27 grams per square meter.

5. The barrier film of claim 1 wherein the barrier film has a water vapor transmission rate of greater than about 13 g/(100 in.sup.2.Math.day.Math.in Hg).

6. The barrier film of claim 5 wherein the barrier film has a water vapor transmission rate of from about 13 g/(100 in.sup.2.Math.day.Math.in Hg) to about 16.1 g/(100 in.sup.2.Math.day.Math.in Hg).

7. The barrier film of claim 1 wherein the barrier film has a weight of from about 22.19 grams per square meter to about 24.53 grams per square meter.

8. The barrier film of claim 7 wherein the barrier film has a weight of from about 22.78 grams per square meter to about 23.94 grams per square meter.

9. The barrier film of claim 1 wherein the nylon film is extrusion coated by the steps comprising: a) feeding the ethylene-methylacrylate copolymer and the at least one block copolymer into an extruder where the copolymers are heated and sheared to blend and melt the resins and form a molten polymer, and wherein the copolymer blend has a residence time in the extruder of from about one minute to about three minutes; b) forcing the molten polymer from the extruder through a slit or die set at a temperature of from about 289 C. to about 320 C.; c) applying the molten polymer directly to the nylon film along with a layer of ozone; d) allowing the coated nylon film to be nipped between a chill roll and a rubber roll to achieve a predetermined lamination bond strength.

10. A method of using the barrier film of claim 1 wherein the extrusion coated barrier film is thermally laminated to expanded polystyrene foam boards.

11. A barrier film comprising a biaxially oriented nylon film extrusion coated with a polymer blend, wherein the polymer blend consists of (a) an ethylene-methylacrylate copolymer, and (b) a block copolymer comprising rigid polyamide blocks and soft polyether blocks.

12. The barrier film of claim 11 wherein the nylon film is a 30-gauge to 60-gauge biaxially oriented film.

13. The nylon film of claim 11 wherein the nylon film has a weight of from about 13.22 grams per square meter to about 14.62 grams per square meter.

14. The barrier film of claim 11 wherein the barrier film has a water vapor transmission rate of greater than about 13 g/(100 in.sup.2.Math.day.Math.in Hg).

15. The barrier film of claim 11 wherein the barrier film has a weight of from about 22.19 grams per square meter to about 24.53 grams per square meter.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) There are no figures in the application.

DETAILED DESCRIPTION OF THE PRESENT DEVELOPMENT

(2) The following description is intended to provide the reader with a better understanding of the invention. The description is not intended to be limiting with respect to any element not otherwise limited within the text.

(3) The barrier film of the present invention is made by extrusion coating a polymer blend onto a nylon film. The nylon film is preferably a biaxially oriented nylon film (biax). More preferably, the nylon film is a 30- to 60-gauge biax film. More preferably, the nylon film is a 48-gauge biax film.

(4) The polymer blend comprises an extrusion-processed blend comprising an acid copolymer and block copolymers. The copolymers comprise rigid polyamide blocks and soft polyether blocks. Exemplary copolymers are ethylene-methylacrylate copolymers, sold under the tradename EMAC by Westlake Chemical Co. of Houston, Tex., and in particular EMAC SP 2207, EMAC SP 2403, EMAC SP 2268 and EMAC SP2409. Exemplary polyether block polyamide elastomers include those sold under the trade name Pebax by Arkema Inc. of Philadelphia Pa., such as Pebax MH 1567, Pebax MV 1074 and Pebax MV 3000.

(5) The polymer coating is produced by extrusion processing. The extrusion process allows for control of the rate of reaction by changes in the process parameters, including the extruder temperatures, melt temperature, residence time of polymers in the extruder, nip pressure, polymer blend ratios and coating weight thickness. To produce the coating, the polymer blend reactants are fed into the extruder where the material is heated and sheared to properly blend and melt the two resins. The material is then conveyed through the extruder at a rate such that the materials have a residence time in the extruder of from about one minute to about three minutes and more preferably about 1.75 minutes to about 2.75 minutes. The molten polymer is then forced from the extruder through a slit or die at from about 289 C. to about 320 C., and more preferably at from about 296.8 C. to about 312.0 C. The molten polymer is directly applied to the barrier film along with a layer of ozone. The coated barrier film is then nipped between a chill roll and rubber roll to achieve the required lamination bond strength.

(6) The resulting coated barrier film has a water vapor transmission rate of greater than about 13 g/(100 in.sup.2.Math.day.Math.in Hg), expressed as US PERMS. In a preferred embodiment, the coated barrier film has a water vapor transmission rate of from about 13 g/(100 in.sup.2.Math.day.Math.in Hg) to about 16.1 g/(100 in.sup.2.Math.day.Math.in Hg). For example:

(7) TABLE-US-00001 US PERMS SAMPLE g/(100 in.sup.2 .Math. day .Math. in Hg) Control Sample 0.633 (48 gauge polypropylene extrusion coated with 0.4 mil of resin) Inventive Sample 13.8 (nylon extrusion coated with 0.4 mil of Pebax/EMAC blend)

(8) The weight of the coated barrier film may be in the range of from about 22.19 grams per square meter to about 24.53 grams per square meter, and more preferably from about 22.78 grams per square meter to about 23.94 grams per square meter. The weight of the nylon film may be in the range of from about 13.22 grams per square meter to about 14.62 grams per square meter, and more preferably from about 13.88 grams per square meter to about 14.27 grams per square meter.

(9) Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the presently disclosed subject matter pertains. Representative methods, devices, and materials are described herein, but are not intended to be limiting unless so noted.