Heterogeneous foam materials

Claim 2

A heterogeneous polymeric foam structure of interconnected open-cells obtained from at least one water-in-oil emulsion, wherein the foam structure has at least two distinct regions that differ by at least about 20% with regard to one or more of polymer density, polymer composition, surface properties, or microcellular morphology.

Claim 3

The heterogeneous foam of claim 1 wherein the foam has an aggregate density of less than about 0.05 g/cc.

Claim 4

The heterogeneous foam of claim 1 wherein the foam comprises a) a continuous region; and b) discrete, unconnected regions dispersed in the continuous region.

Claim 5

The heterogeneous foam of claim 4 wherein the aggregate volume of the discrete regions is from about 10% to about 80% of the foam's total volume.

Claim 6

The heterogeneous foam of claim 1 wherein the foam comprises at least two discrete, continuous regions.

Claim 7

The heterogeneous foam of claim 5 wherein each continuous region comprises from about 20% to about 80% of the foam's total volume.

Claim 8

The heterogeneous foam of claim 1 wherein one distinct region has a mean cell size of not more than about 50 μm and a second distinct region has a mean cell size of from about 20 to about 200 μm, and wherein the mean cell sizes for the two regions differ by at least 20%.

Claim 9

The heterogeneous foam of claim 1, wherein one distinct region has an average hole size of from about 1 to about 7 μm and a second distinct region has an average hole size of from about 5 to about 45 μm, and wherein the average hole sizes for the two regions differ by at least about 20%.

Claim 10

An absorbent heterogeneous hydrophilic polymeric foam structure of interconnected open-cells, wherein the foam has at least two distinct regions that differ by at least about 20% with regard to one or more of polymer density, polymer composition, surface properties, or microcellular morphology.

Claim 11

An absorbent heterogeneous hydrophilic polymeric foam structure of interconnected open-cells, wherein the foam has at least two distinct regions that differ by at least about 20% with regard to one or more of polymer density, polymer composition, surface properties, or microcellular morphology.

Claim 12

The heterogeneous foam of claim 9 wherein the foam comprises a) a continuous region; and b) discrete, unconnected regions dispersed in the continuous region.

Claim 13

The heterogeneous foam of claim 10 wherein the aggregate volume of the discrete regions is from about 10% to about 80% of the foam's total volume.

Claim 14

The heterogeneous foam of claim 10 wherein the dispersed, unconnected regions are made from essentially the same material having a Tg of from about 30° C. to about 95° C., the continuous region has a Tg of less than about 50° C., and wherein the Tgs for the continuous and dispersed, unconnected regions differ by at least 20%.

Claim 15

The heterogeneous foam of claim 12 wherein the dispersed, unconnected regions have a Tg of from about 35° C. to about 75° C. and the continuous region has a Tg of less than about 30° C.

Claim 16

The heterogeneous foam of claim 10 wherein the dispersed, unconnected regions are made from essentially the same material having a Tg that is at least about 10° C. greater than the use temperature for the foam, and the continuous region has a Tg of about the same as the use temperature for the foam.

Claim 17

The heterogeneous foam of claim 10 wherein the dispersed, unconnected regions are made from essentially the same material having a Tg that is at least about 10° C. greater than the use temperature for the foam, and the continuous region has a Tg that is no higher than about 10° C. less than the use temperature for the foam.

Claim 18

The heterogeneous foam of claim 10 wherein the foam has an aggregate RTCD of about 40% or less when measured under a confining pressure of 5.1 kPa.

Claim 19

The heterogeneous foam of claim 9 wherein the foam comprises at least two discrete, continuous regions.

Claim 20

The heterogeneous foam of claim 17 wherein each continuous region comprises from about 20% to about 80% of the foam's total volume.

Claim 21

The foam of claim 17, wherein one distinct region has a capillary suction specific surface area per volume of at least about 0.025 m 2 /cc and a second distinct region has a capillary suction specific surface area per volume of from about 0.0075 to about 0.06 m 2 /cc, and wherein the capillary suction specific surface area per volume for the two regions differ by at least 20%.

Claim 22

The foam of claim 17, wherein one distinct region has a capillary suction specific surface area per volume of at least about 0.05 m 2 /cc and a second distinct region has a capillary suction specific surface area per volume of from about 0.0075 to about 0.04 m 2 /cc.

Claim 23

The foam of claim 17 having a length, width and depth, wherein one region is under, in terms of depth of the foam, the other region.

Claim 24

The foam of claim 17 having a length and width and further having three distinct continuous regions, where the regions run longitudinally such that there are two outer regions adjacent a middle region.

Claim 25

The foam of claim 22, wherein the two outer regions have about the same mean cell diameter, and wherein the middle region has a mean cell diameter that is at least about 20% greater than the mean cell diameter of each of the outer regions.

Claim 26

The foam of claim 23, wherein the middle region has a mean cell diameter that is at least about 50% greater than the mean cell diameter of each of the outer regions.

Claim 27

The foam of claim 23, wherein the two outer regions each have a mean cell diameter of not more than about 50 μm and the middle region has a mean cell diameter of from about 80 to about 180 μm.

Claim 28

The polymeric foam of claim 9, wherein the distinct regions differ in that: 1) they are not formed from the same monomer components; or 2) if formed from the same monomer components, the relative amount of at least one monomer component differs by at least about 20%.

Claim 29

The foam of claim 26, wherein if the distinct regions are formed from the same monomoer components, the relative amount of at least one monomer component differs by at least about 35%.

Claim 30

A heterogeneous polymeric foam structure of interconnected open-cells, wherein the foam structure has at least two distinct regions that differ by at least about 20% with regard to one or more of polymer density, polymer composition, surface properties, or microcellular morphology, and wherein the foam is prepared by the process comprising the steps of: A) forming a first water-in-oil emulsion from: 1) an oil phase comprising: a) from about 85 to about 98% by weight of a monomer component capable of forming a copolymer having a Tg of about 95° C. or lower, the monomer component comprising: i) from about 20 to about 70% by weight of at least one substantially water-insoluble monofunctional monomer capable of forming an atactic amorphous polymer having a Tg of about 25° C. or lower; ii) from about 10 to about 50% by weight of at least one substantially water-insoluble monofunctional comonomer capable of imparting toughness about equivalent to that provided by styrene; iii) from about 5 to about 50% by weight of a first substantially water-insoluble, polyfunctional crosslinking agent selected from divinylbenzenes, trivinylbenzenes, divinyltoluenes, divinylxylenes, divinylnaphthalenes divinylalkylbenzenes, divinylphenanthrenes, divinylbiphenyls, divinyldiphenylmethanes, divinylbenzyls, divinylphenylethers, divinyldiphenylsulfides, divinylfurans, divinylsulfide, divinylsulfone, and mixtures thereof; and iv) from 0 to about 15% by weight of a second substantially water-insoluble, polyfunctional crosslinking agent selected from polyfunctional acrylates, methacrylates, acrylamides, methacryl-amides, and mixtures thereof; and b) from about 2 to about 15% by weight of an emulsifier component which is soluble in the oil phase and which is capable of forming a stable water-in-oil emulsion, the emulsifier component comprising a primary emulsifier having at least about 40% by weight emulsifying components selected from diglycerol monoesters of branched C 16 -C 24 fatty acids, linear unsaturated C 16 -C 22 fatty acids, and linear saturated C 12 -C 4 fatty acids; sorbitan monoesters of branched C 16 -C 24 fatty acids, linear unsaturated C 16 -C 22 fatty acids, linear saturated C 12 -C 14 fatty acids; diglycerol monoaliphatic ethers of branched C 16 -C 24 alcohols, linear unsaturated C 16 -C 22 alcohols, and linear saturated C 12 -C 14 alcohols, and mixtures thereof; and 2) a water phase comprising an aqueous solution containing: (a) from about 0.2 to about 20% by weight of a water-soluble electrolyte; and (b) an effective amount of a polymerization initiator; 3) a volume to weight ratio of water phase to oil phase in the range of from about 20:1 to about 200:1; B) optionally forming a second, distinct water-in-oil emulsion which is different in at least one respect from the first emulsion; and C) either p2 1) a) combining the first and second water-in-oil emulsions in a forming vessel prior to polymerizing the monomer components in the oil phase of either of the water-in-oil emulsions; and b) polymerizing both emulsions to form a polymeric, heterogeneous foam; 2) a) partly or completely polymerizing the monomer components in the oil phase of the first water-in-oil emulsion; b) combining the material from step C)2)a) and the second water-in-oil emulsion; and c) polymerizing the second emulsion, and the first emulsion if combined when partly cured, to provide a polymeric, heterogeneous foam; or 3) making only the first water-in-oil emulsion while varying the process conditions by which it is formed in a controlled fashion, either rhythmically or continuously, using a single emulsion forming head, to form a heterogeneous foam.

Claim 31

A heterogeneous polymeric foam structure of interconnected open-cells, wherein the foam structure has at least two distinct regions that differ by at least about 20% with regard to one or more of polymer density, polymer composition, surface properties, or microcellular morphology, and wherein the foam is prepared by the process comprising the steps of: A) forming a first water-in-oil emulsion from: 1) an oil phase comprising: a) from about 85 to about 98% by weight of a monomer component capable of forming a copolymer having a Tg of about 95° C. or lower, the monomer component comprising: i) from about 20 to about 70% by weight of at least one substantially water-insoluble monofunctional monomer capable of forming an atactic amorphous polymer having a Tg of about 25° C. or lower; ii) from about 10 to about 50% by weight of at least one substantially water-insoluble monofunctional comonomer capable of imparting toughness about equivalent to that provided by styrene; iii) from about 5 to about 50% by weight of a first substantially water-insoluble, polyfunctional crosslinking agent selected from divinylbenzenes, trivinylbenzenes, divinyltoluenes, divinylxylenes, divinylnaphthalenes divinylalkylbenzenes, divinylphenanthrenes, divinylbiphenyls, divinyldiphenylmethanes, divinylbenzyls, divinylphenylethers, divinyldiphenylsulfides, divinylfurans, divinylsulfide, divinylsulfone, and mixtures thereof; and iv) from 0 to about 15% by weight of a second substantially water-insoluble, polyfunctional crosslinking agent selected from polyfunctional acrylates, methacrylates, acrylamides, methacryl-amides, and mixtures thereof; and b) from about 2 to about 15% by weight of an emulsifier component which is soluble in the oil phase and which is capable of forming a stable water-in-oil emulsion, the emulsifier component comprising a primary emulsifier having at least about 40% by weight emulsifying components selected from diglycerol monoesters of branched C 16 -C 24 fatty acids, linear unsaturated C 16 -C 22 fatty acids, and linear saturated C 12 -C 4 fatty acids; sorbitan monoesters of branched C 16 -C 24 fatty acids, linear unsaturated C 16 -C 22 fatty acids, linear saturated C 12 -C 14 fatty acids; diglycerol monoaliphatic ethers of branched C 16 -C 24 alcohols, linear unsaturated C 16 -C 22 alcohols, and linear saturated C 12 -C 14 alcohols, and mixtures thereof; and 2) a water phase comprising an aqueous solution containing: (a) from about 0.2 to about 20% by weight of a water-soluble electrolyte; and (b) an effective amount of a polymerization initiator; 3) a volume to weight ratio of water phase to oil phase in the range of from about 20:1 to about 200:1; B) optionally forming a second, distinct water-in-oil emulsion which is different in at least one respect from the first emulsion; and C) either p2 1) a) combining the first and second water-in-oil emulsions in a forming vessel prior to polymerizing the monomer components in the oil phase of either of the water-in-oil emulsions; and b) polymerizing both emulsions to form a polymeric, heterogeneous foam; 2) a) partly or completely polymerizing the monomer components in the oil phase of the first water-in-oil emulsion; b) combining the material from step C)2)a) and the second water-in-oil emulsion; and c) polymerizing the second emulsion, and the first emulsion if combined when partly cured, to provide a polymeric, heterogeneous foam; or 3) making only the first water-in-oil emulsion while varying the process conditions by which it is formed in a controlled fashion, either rhythmically or continuously, using a single emulsion forming head, to form a heterogeneous foam.

Claim 32

The heterogeneous foam of claim 28 wherein the foam comprises a) a continuous region; and b) discrete, unconnected regions dispersed in the continuous region.

Claim 33

The heterogeneous foam of claim 29 wherein the dispersed, unconnected regions comprise from about 10% to about 80% of the foam's volume and are made from essentially the same material having a Tg that is at least about 10° C. greater than the use temperature for the foam, and the continuous region has a Tg of about the same as the use temperature for the foam.

Claim 34

The heterogeneous foam of claim 28 wherein the foam comprises at least two discrete, continuous regions.

Claim 35

The heterogeneous foam of claim 31 wherein each continuous region comprises from about 20% to about 80% of the foam's total volume.

Claim 36

The foam of claim 32, wherein one distinct region has a capillary suction specific surface area per volume of at least about 0.025 m 2 /cc and a second distinct region has a capillary suction specific surface area per volume of from about 0.0075 to about 0.06 m 2 /cc, and wherein the capillary suction specific surface area per volume for the two regions differ by at least 20%.

Claim 37

The foam of claim 32, wherein the foam has a length, width and depth, wherein one region is under, in terms of depth of the foam, the other region.