Hot melt adhesive for spiral wound membrane bonding

1 . A separation apparatus including:

a first composite membrane capable of separating a first constituent from a feed fluid mixture and having a barrier layer with a barrier surface and an opposing support layer with a support surface;

a second composite membrane capable of separating the first constituent from the feed fluid mixture and having a barrier layer with a barrier surface and an opposing support layer with a support surface;

a fluid permeable permeate carrier sheet having opposing first and second surfaces;

wherein the first composite membrane and the second composite member are arranged to that the support surface of the first composite membrane is adjacent the fluid permeable permeate carrier sheet first surface and the support surface of the second composite membrane support surface is adjacent the fluid permeable permeate carrier sheet second surface; and

a thermoplastic hot melt adhesive disposed in one or more discrete areas between the first composite membrane, the fluid permeable permeate carrier sheet and the second composite membrane, the adhesive forming a fluid impermeable bonded area between a portion of the first composite membrane support surface, the fluid permeable permeate carrier sheet and a portion of the second composite membrane support surface.

2 . The separation apparatus according to claim 1 , wherein the thermoplastic hot melt adhesive comprises:

a thermoplastic homopolymer or copolymer comprising butene;

tackifier; and

optionally one or more additives.

3 . The separation apparatus according to claim 1 , wherein the thermoplastic hot melt adhesive comprises:

a thermoplastic homopolymer or copolymer comprising butene;

wax;

tackifier; and

optionally one or more additives.

4 . The separation apparatus according to claim 1 , wherein the hot melt adhesive comprises:

a thermoplastic homopolymer or copolymer comprising butene;

a thermoplastic homopolymer or copolymer free of butene;

tackifier; and

optionally one or more additives.

5 . The separation apparatus according to claim 1 , wherein the bonded area has a penetration of no more than 0.25 inches when tested using the veining test.

6 . The separation apparatus according to claim 1 , wherein the separation apparatus further comprises a third composite membrane capable of separating the first constituent from the feed fluid mixture and having a barrier layer with a barrier surface and an opposing support layer with a support surface, wherein the third membrane barrier surface is adjacent the second membrane barrier surface; and a porous feed spacer is disposed between the second composite membrane and the third composite membrane.

7 . The separation apparatus according to claim 1 , wherein at least one of the the first composite membrane and the second composite membrane comprises microporous substrate disposed between the barrier layer and the support layer.

8 . The separation apparatus according to claim 1 , wherein the first composite membrane, the second composite membrane and the fluid permeable permeate carrier sheet each comprise a plurality of peripheral edges and the thermoplastic hot melt adhesive is disposed around most of the peripheral edges forming a bonded area around most of the periphery of the first composite membrane, the second composite membrane and the fluid permeable permeate carrier sheet, wherein at least a portion of one peripheral edge of the first composite membrane, the second composite membrane and the fluid permeable permeate carrier sheet is not bonded and forms a permeate exit and the central portion of the first composite membrane, the second composite membrane and the fluid permeable permeate carrier sheet is not bonded and forms a permeate flow channel fluidly connected to the permeate exit.

9 . The separation apparatus according to claim 1 , comprising a plurality of filter packs fluidly connected to a permeate tube and wound around the permeate tube, wherein each filter pack comprises the first and the second composite membranes peripherally bonded to the fluid permeable carrier sheet with the hot melt adhesive.

10 . The separation apparatus according to claim 1 , wherein the thermoplastic hot melt adhesive comprises butene and has a viscosity at 180° C. of about 500 to about 8,000 mPas; and/or a softening point of about 55 to about 150° C.; and/or an open time of about 30 seconds or more and/or a Shore A hardness of about 50 or greater.

11 . The separation apparatus according to claim 1 , wherein the thermoplastic hot melt adhesive comprises butene and has a viscosity at 180° C. of about 800 to about 7,500 mPas; and/or a softening point of about 80 to about 105° C.; and/or an open time of about 70 seconds or more and/or a Shore A hardness of about 50 to about 95.

12 . A separation apparatus including:

a first composite membrane capable of separating a first constituent from a feed fluid mixture and having a barrier layer with a barrier surface and an opposing support layer with a support surface;

a second composite membrane capable of separating the first constituent from the feed fluid mixture and having a barrier layer with a barrier surface and an opposing support layer with a support surface;

a fluid permeable permeate carrier sheet having opposing first and second surfaces;

wherein the first composite membrane and the second composite membrane are arranged so that the support surface of the first composite membrane is adjacent the fluid permeable permeate carrier sheet first surface and the support surface of the second composite membrane is adjacent the fluid permeable permeate carrier sheet second surface; and

a thermoplastic hot melt adhesive disposed in one or more discrete areas of the first membrane layer, the carrier sheet and/or the second membrane layer.

13 . The separation apparatus according to claim 12 , wherein the thermoplastic hot melt adhesive comprises:

a thermoplastic homopolymer or copolymer comprising butene;

tackifier; and

optionally one or more additives.

14 . The separation apparatus according to claim 1 , wherein the thermoplastic hot melt adhesive comprises butene, has a viscosity at 180° C. of about 500 to about 8,000 mPas, a softening point of about 55 to about 150° C., and an open time of about 30 seconds or more.

15 . The separation apparatus according to claim 12 , wherein the thermoplastic hot melt adhesive comprises butene, has a viscosity at 180° C. of about 500 to about 8,000 mPas, a softening point of about 55 to about 150° C., and an open time of about 30 seconds or more.