Method for continuous curing of hipe into hipe foams

• US 6,525,106 B1
• Filed: 08/07/2001
• Issued: 02/25/2003
• Est. Priority Date: 02/22/1999
• Status: Expired due to Term

• Current Assignee: The Procter & Gamble Company
• Original Assignee: The Procter & Gamble Company
• Inventors: Dyer, John Collins, Dick, Stephen Thomas, DesMarais, Thomas Allen, Shiveley, Thomas Michael, Hird, Bryn
• Primary Examiner(s): Foelak, Morton
• Application Number:
  US09/890,918
• Time in Patent Office: 567 Days
• Field of Search: 521/64, 521/63
• US Class Current: 521/64
• CPC Class Codes: C08J 2201/028 Foaming by preparing of a high internal phase emulsion
• CPC Class Codes: C08J 2333/00 Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Derivatives of such polymers
• CPC Class Codes: C08J 9/28 by elimination of a liquid phase from a macromolecular composition or article, e.g. drying of coagulum

Abstract

This application relates to flexible, microporous, open-celled polymeric foam materials with physical characteristics that make them suitable for a variety of uses. This application particularly relates to methods particularly suitable for continuously curing high internal phase emulsions to form such foams.

Claims

1. A method of continuously curing a HIPE into a HIPE foam, the method comprising the steps of:

A) continuously providing a HIPE, said HIPE comprising;

1) an oil phase comprising;

a) from about 85 to about 99% by weight of a monomer component capable of forming a copolymer having a Tg value of below about 90°

C. or lower, the monomer component comprising;

i) from about 5 to about 80% by weight of a substantially water-insoluble, monofunctional monomer capable of forming a polymer having a Tg of about 35°

C. or less;

ii) from about 0 to about 70% by weight of a substantially water-insoluble, monofunctional comonomer capable of imparting other desired properties to the foam;

iii) about 5 to about 80% by weight of at least one substantially water-insoluble, polyfunctional crosslinking agent; and

b) from about 1 to about 20% by weight of an emulsifier component which is soluble in the oil phase and which is suitable for forming a stable water-in-oil emulsion; and

2) a water phase comprising an aqueous solution containing;

(a) from about 0.2 to about 40% by weight of a water-soluble electrolyte; and

(b) an effective amount of a polymerization initiator;

wherein the emulsion has a volume to weight ratio of water phase to oil phase in the range of from about 8;

1 to about 140;

1;

B) transferring said HIPE into a curing chamber, wherein said curing chamber is provided with means to maintain said HIPE at a curing temperature, suitable for polymerizing and crosslinking said monomer, comonomer, and crosslinking agent;

C) maintaining said HIPE in said curing chamber for a residence time sufficient for at least partial curing of said HIPE into a nascent HIPE foam;

D) characterized in that said nascent HIPE foam is continuously withdrawn from said curing chamber; and

E) further processing said nascent HIPE foam into a cured HIPE foam.

2. The process of claim 1 wherein:

1) the oil phase comprises;

a) from about 90 to about 97% by weight of a monomer component capable of forming a copolymer having a Tg value from about 15°

to about 50°

C., the monomer component comprising;

i) from about 40 to about 70% by weight monomer selected from the group consisting of C₄-C₁₄ alkyl acrylates, aryl acrylates, C₆-C₁₆ alkyl methacrylates, dienes, C₄-C₁₂ alkyl styrenes and mixtures thereof;

ii) from about 15 to about 23% by weight comonomer selected from the group consisting of styrene, ethyl styrene and mixtures thereof;

iii) from about 5 to about 18% by weight divinyl benzene; and

b) from about 3 to about 10% by weight of the emulsifier component; and

2) the water phase comprises from about 1 to about 40% calcium chloride.

3. A method according to claim 2 wherein said curing chamber has a cross section selected from the group consisting of rectangular, circular, triangular, annular, oval, hourglass, dog bone, and asymmetric.

4. A method according to claim 3 wherein said curing chamber has a rectangular cross section.

5. A method according to claim 4 wherein said rectangular curing chamber has a large width:

thickness aspect ratio so as to form said HIPE into a HIPE foam having a sheet form.

6. A method according to any of the above claims wherein said curing chamber comprises an apparatus that constrains said HIPE between a curing drum and a confining web.

7. A method according to claim 1 wherein said curing temperature is greater that about 65°

.