Process for Preparing Membranes

Patent metadata

Field	Value
Publication number	US-10213743-B2
Application number	US-201515113516-A
Country	US
Kind code	B2
Filing date	Jan 23, 2015
Priority date	Jan 27, 2014
Publication date	Feb 26, 2019
Grant date	Feb 26, 2019

Abstract

A process for preparing an ion-exchange membrane having a textured surface profile comprising the steps (i) and (ii): (i) applying a radiation-curable composition to a membrane in a patternwise manner; and (ii) irradiating and thereby curing the radiation-curable composition present on the membrane; wherein the radiation-curable composition comprises: a) 10 to 65 wt % of curable ionic compound(s) comprising one ethylenically unsaturated group; b) 3 to 60 wt % of crosslinking agent(s) comprising at least two ethylenically unsaturated groups and having a number average molecular weight below 800; c) 0 to 70 wt % of inert solvent(s); d) 0 to 10 wt % of free-radical initiator(s); and e) 0.5 to 25 wt % of thickening agent(s).

First claim

The invention claimed is:

1. A process for preparing an ion-exchange membrane having a textured surface profile comprising the steps (i) and (ii):
(i) applying a radiation-curable composition to a membrane in a patternwise manner; and
(ii) irradiating and thereby curing the radiation-curable composition present on the membrane;
wherein the radiation-curable composition comprises:
a) 10 to 65 wt % of curable ionic compound(s) comprising one ethylenically unsaturated group;
b) 3 to 60 wt % of crosslinking agent(s) comprising at least two ethylenically unsaturated groups and having a number average molecular weight below 800;
c) 0 to 70 wt % of inert solvent(s);
d) 0 to 10 wt % of free-radical initiator(s); and
e) 0.5 to 25 wt % of thickening agent(s) comprising an inorganic filler in a form which has a BET surface area greater than 50 m 2 /g.

2. The process according to claim 1 wherein during curing some or all components of the composition polymerise to form the desired surface profile.

3. The process according to claim 1 wherein the radiation-curable composition used in step (i) has a viscosity of 30 to 1000 Pa·s at a shear rate of 0.1 s −1 and a viscosity of <20 Pa·s at a shear rate of 1000 s −1 , when measured at 20° C.

4. The process according to claim 1 wherein the ratio of the viscosity when measured at a shear rate of 0.1 s −1 at 20° C. to the viscosity when measured at a shear rate of 1000 s −1 at 20° C. is between 1.5 and 5000.

5. The process according to claim 1 wherein the textured surface profile comprises protrusions which have an average height of 5 to 500 μm.

6. The process according to claim 1 wherein step i) comprises rotary screen-printing, flatbed screen-printing or rotary-stop-cylinder screen-printing of the radiation-curable composition onto the membrane in a patternwise manner.

7. The process according to claim 1 wherein the textured surface profile comprises protrusions which have an average length to average width ratio of 10:1 to 1:10.

8. The process according to claim 1 wherein the radiation-curable composition comprises:
a) 12 to 60 wt % of curable ionic compound(s) comprising one acrylic group and one or more acidic or basic group selected from sulfo, carboxy, phosphato, quaternary amino and tertiary amino groups;
b) 4 to 45 wt % of crosslinking agent(s) comprising at least two ethylenically unsaturated groups and having a number average molecular weight below 800;
c) 5 to 50 wt % of inert solvent(s);
d) 0.01 to 10 wt % of free-radical initiator(s);
e) 1 to 15 wt % of thickening agent wherein the inorganic filler is selected from the group consisting of hydrophilic metal oxides, carbon black, clays and calcium carbonate; and
f) 1 to 15 wt % of crosslinking agent(s) comprising at least two ethylenically unsaturated groups and having a number average molecular weight of 800 to 8,000 Daltons.

9. A process for preparing an ion-exchange membrane having a textured surface profile comprising the steps (i) and (ii):
(i) applying a radiation-curable composition to a membrane in a patternwise manner; and
(ii) irradiating and thereby curing the radiation-curable composition present on the membrane;
wherein the radiation-curable composition comprises:
a) 10 to 65 wt % of curable ionic compound(s) comprising one ethylenically unsaturated group;
b) 3 to 60 wt % of crosslinking agent(s) comprising at least two ethylenically unsaturated groups and having a number average molecular weight below 800;
c) 0 to 70 wt % of inert solvent(s);
d) 0 to 10 wt % of free-radical initiator(s); and
e) 0.5 to 25 wt % of thickening agent(s)
which further comprises the preparation of the membrane used in step (i) by a process comprising the steps (A) and (B):

(A) impregnating a porous support with a radiation-curable composition;
(B) forming the membrane by irradiating and thereby curing the radiation-curable curable composition present in the porous support.

10. The process according to claim 9 wherein the radiation-curable composition used in step (i) has a higher viscosity than the radiation-curable composition used in step (A).

11. The process according to claim 1 wherein the thickening agent e) comprises a rheology modifier and/or a particulate solid.

12. The process of claim 11 wherein the particulate solid comprises an inorganic filler selected from the group consisting of crystalline and amorphous silica, carbon black, clay particles, aluminum silicate, metal oxides and metal carbonates wherein the particulate solid has a specific surface area greater than 50 m 2 /g as may be determined by the Brunauer, Emmett and Teller (BET) method of adsorption of nitrogen gas.

13. The process according to claim 1 wherein:
(a) the radiation-curable composition used in step (i) has a viscosity of 30 to 1000 Pa·s at a shear rate of 0.1 s −1 and a viscosity of <20 Pa·s at a shear rate of 1000 s −1 , when measured at 20° C.;
(b) the ratio of the viscosity when measured at a shear rate of 0.1 s −1 at 20° C. to the viscosity when measured at a shear rate of 1000 s −1 at 20° C. is between 1.5 and 5000;
(c) the textured surface profile comprises protrusions which have an average height of 5 to 500 μm; and
(d) the textured surface profile comprises protrusions which have an average length to average width ratio of 10:1 to 1:10.

14. The process of claim 1 wherein:
(a) the radiation-curable composition used in step (i) has a viscosity of 30 to 1000 Pa·s at a shear rate of 0.1 s −1 and a viscosity of <20 Pa·s at a shear rate of 1000 s −1 , when measured at 20° C.;
(b) the ratio of the viscosity when measured at a shear rate of 0.1 s −1 at 20° C. to the viscosity when measured at a shear rate of 1000 s −1 at 20° C. is between 1.5 and 5000;
(c) the textured surface profile comprises protrusions which have an average height of 5 to 500 μm; and
(d) the textured surface profile comprises protrusions which have an average length to average width ratio of 10:1 to 1:10;
wherein the radiation-curable composition comprises:
a) 12 to 60 wt % of curable ionic compound(s) comprising one acrylic group and one or more acidic or basic group selected from sulfo, carboxy, phosphato, quaternary amino and tertiary amino groups;
b) 4 to 45 wt % of crosslinking agent(s) comprising at least two ethylenically unsaturated groups and having a number average molecular weight below 800;
c) 5 to 50 wt % of inert solvent(s);
d) 0.01 to 10 wt % of free-radical initiator(s);
e) 1 to 15 wt % of thickening agent wherein the inorganic filler is selected from the group consisting of hydrophilic metal oxides, carbon black, clays and calcium carbonate; and
f) 1 to 15 wt % of crosslinking agent(s) comprising at least two ethylenically unsaturated groups and having a number average molecular weight of 800 to 8,000 Daltons.

Assignees

• Fujifilm Mfg Europe Bv

Inventors

• Van Berchum Bastiaan
• Van Engelen Johannes
• Van Baak Willem
• Batting Adam

Classifications

• C09D11/02

  Printing inks (C09D11/30 takes precedence) · CPC title

• B01D2323/34

  Use of radiation · CPC title

• B01D2325/08

  Patterned membranes · CPC title

• B01D2323/30

  Cross-linking · CPC title

• C09D4/00

  Coating compositions, e.g. paints, varnishes or lacquers, based on organic non-macromolecular compounds having at least one polymerisable carbon-to-carbon unsaturated bond {; Coating compositions, based on monomers of macromolecular compounds of groups C09D183/00 - C09D183/16} · CPC title