PLEATED COMPOSITE PERVAPORATION LAMINATE AND METHOD OF MAKING SAME

Abstract

A composite pervaporation laminate incorporates a thin hydrophilic film laminated on a formable macroporous support layer. The method for making the membrane involves solution casting a thin film on a carrier substrate and transferring the said film onto a macroporous support by hot pressing, such as by decal transfer. Ultra-thin defect-free film, such as less than 5 micrometers, are laminated using this method to achieve very high-water transmission rates and very low or zero gas permeation. The membrane can then be formed into a three-dimensional structure by pleating or corrugating to increase the surface area. The membrane can be used as spacers in an ERV application.

Claims

1. A process for making a composite pervaporation laminate comprising: a) casting a thin film moisture transfer membrane onto a carrier substrate to produce a cast thin film composite; b) transferring the thin film moisture transfer membrane of the cast thin film composite to a first porous support layer to produce a composite pervaporation laminate; wherein the thin film moisture transfer membrane has a thickness of less than 5 micrometers.

2. The process of claim 1, wherein the thin film moisture transfer membrane has a thickness of less than 5 micrometers.

3. The process of claim 1, wherein the thin film moisture transfer membrane has a thickness of less than 3 micrometers.

4. The process of claim 1, wherein the thin film moisture transfer membrane has a thickness of less than 2 micrometers.

5. The process of claim 1, wherein the thin film moisture transfer membrane comprises polyether block amide (PEBA).

6. The process of claim 1, wherein transferring the thin film moisture transfer membrane to a first porous support layer comprises heating and pressing the cast thin film composite to the first porous support layer.

7. The process of claim 1, further comprising pleating the composite pervaporation laminate to form a pleated composite pervaporation laminate having a plurality of pleats.

8. The process of claim 7, wherein the pleated composite pervaporation laminate has a surface area density of at least 1.5.

9. The process of claim 7, wherein the pleated composite pervaporation laminate has a surface area density of at least 3.0.

10. The process of claim 1, further comprising attaching a second porous support layer to the composite pervaporation laminate, opposite the first porous support layer to produce a tri-layer composite pervaporation laminate.

11. The process of claim 10, wherein attaching said second porous support layer comprises pressing and heating the composite pervaporation laminate to the second porous support layer, to produce said tri-layer composite pervaporation laminate.

12. The process of claim 10, further comprising pleating the composite pervaporation laminate to form a pleated composite pervaporation laminate having a plurality of pleats.

13. The process of claim 12, wherein the pleated composite pervaporation laminate has a surface area density of at least 1.5.

14. The process of claim 12, wherein the pleated composite pervaporation laminate has a surface area density of at least 3.0.

15. The process of any of claim 12, wherein the first support layer is a microporous support layer having a pore size of 10 micrometers or more.

16. The process of any of claim 15, wherein the first support layer is porous polyolefin.

17. The process of any of claim 15, wherein the first support layer is porous fluoropolymer.

18. The process of any of claim 12, wherein the second support layer is a macroporous support layer having a pore size of 10 micrometers or more.

19. The process of any of claim 18, wherein the second support layer is porous polyolefin.

20. The process of any of claim 18, wherein the second support layer is porous fluoropolymer.

Description

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

[0043] The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention, and together with the description serve to explain the principles of the invention.

[0044] FIG. 1 shows a cross sectional view of an exemplary formable porous support layer having pores.

[0045] FIG. 2 shows a cross sectional view of an exemplary carrier substrate.

[0046] FIG. 3 shows a cross sectional view of an exemplary carrier substrate coated with a moisture transfer polymer solution having a moisture transfer polymer therein.

[0047] FIG. 4 shows a cross sectional view of an exemplary carrier substrate coated with a thin film moisture transfer membrane.

[0048] FIG. 5 shows a cross sectional view of an exemplary composite pervaporation membrane having a thin film moisture transfer membrane attached to a porous support layer.

[0049] FIG. 6 shows a cross sectional view of an exemplary composite pervaporation membrane having a thin film moisture transfer membrane attached between two porous support layers.

[0050] FIG. 7 shows a cross sectional view of a pervaporation module having a pleated composite pervaporation laminate configured in a module frame.

[0051] FIG. 8 shows a cross sectional view of a pervaporation module having a pleated composite pervaporation laminate configured in a module frame and a cover layer configured over the thin film moisture transfer membrane.

[0052] Corresponding reference characters indicate corresponding parts throughout the several views of the figures. The figures represent an illustration of some of the embodiments of the present invention and are not to be construed as limiting the scope of the invention in any manner. Some of the figures may not show all of the features and components of the invention for ease of illustration, but it is to be understood that where possible, features and components from one figure may be included in the other figures. Further, the figures are not necessarily to scale, some features may be exaggerated to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

[0053] As used herein, the terms “comprises,” “comprising,” “includes,” “including,” “has,” “having” or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Also, use of “a” or “an” are employed to describe elements and components described herein. This is done merely for convenience and to give a general sense of the scope of the invention. This description should be read to include one or at least one and the singular also includes the plural unless it is obvious that it is meant otherwise.

[0054] Certain exemplary embodiments of the present invention are described herein and are illustrated in the accompanying figures. The embodiments described are only for purposes of illustrating the present invention and should not be interpreted as limiting the scope of the invention. Other embodiments of the invention, and certain modifications, combinations and improvements of the described embodiments, will occur to those skilled in the art and all such alternate embodiments, combinations, modifications, improvements are within the scope of the present invention.

[0055] As shown in FIG. 1, an exemplary formable porous support layer 60 has a thickness 63 from a thin film surface 62 to a back surface 64 and pores 66 therein. The pores may be macroscopic pores that are larger than 10 μm.

[0056] As shown in FIG. 2, an exemplary carrier substrate 20 has a thickness 23 from a casting surface 22 to a back surface 24.

[0057] As shown in FIG. 3, of an exemplary carrier substrate 20 is coated with a moisture transfer polymer solution 30 having a moisture transfer polymer therein 34.

[0058] As shown in FIG. 4, the exemplary carrier substrate 20 shown in FIG. 3 now has a thin film moisture transfer membrane 40 configured on the casting surface 22 from the moisture transfer polymer cast thereon. The cast thin film composite 45 includes the thin film moisture transfer moisture transfer membrane 40 on the carrier substrate 20. The thin film moisture transfer membrane 40 has a thickness 46 from a casting surface 44, couple to the carrier substrate 20, to an outside surface 48.

[0059] As shown in FIG. 5, an exemplary composite pervaporation laminate 10 has a thin film moisture transfer membrane 40 attached to a porous support layer 60 along an attached surface 54 of the film moisture transfer membrane 40. The composite pervaporation laminate 10 has a thickness 17 from a back surface 64 of the porous support layer 60 to the exposed surface 58 of the thin film moisture transfer membrane 40. The exposed surface 58 may be the casting surface 44 of the thin film moisture transfer membrane 40 after transfer from the carrier substrate to the porous support layer.

[0060] As shown in FIG. 6, an exemplary composite pervaporation laminate 10 is a tri-layer composite pervaporation laminate 85, that has a thin film moisture transfer membrane 40 attached between a porous support layer 60 and a cover layer 80, which is also a porous support layer 82 having pores 86. The composite pervaporation laminate 10 has a thickness 18 from a back surface 64 of the porous support layer 60 to the exposed surface 88 of the cover layer 80. The thin film moisture transfer membrane 40 is protected by being sandwiched between the two porous support layers.

[0061] As shown in FIG. 7, a pervaporation module 90 has a pleated composite pervaporation laminate 10 that is a pleated composite pervaporation laminate 12 having the thin film moisture transfer membrane 40 coupled to the porous support layer 20. The pleated composite pervaporation laminate 10 has a plurality of pleats 70 configured in a module frame 92. The pleats 70 enable a high surface area density and the stiffness of the porous support may enable the pleated composite pervaporation laminate to be free standing. The surface area density is increased as the length of the pleated composite pervaporation laminate, when the pleats are flattened out, is much greater than the length of the cartridge.

[0062] As shown in FIG. 8, a cover layer 80 may be configured over the thin film moisture transfer membrane 40 to protect the thin film moisture transfer membrane 40 and may be a porous material, such as a non-woven or woven material, such as shown in FIG. 6.

[0063] It will be apparent to those skilled in the art that various modifications, combinations and variations can be made in the present invention without departing from the scope of the invention. Specific embodiments, features and elements described herein may be modified, and/or combined in any suitable manner. Thus, it is intended that the present invention cover the modifications, combinations and variations of this invention provided they come within the scope of the appended claims and their equivalents.