Low-density, open-cell, soft, flexible, thermoplastic absorbent foam and method of making foam

Abstract

A soft, flexible, low-density, open-cell, thermoplastic, absorbent foam formed from a foam polymer formula including a balanced amount of a plasticizing agent and a surfactant in combination with a base resin. Thermoplastic elastomers can be added to the foam polymer formula to improve softness, flexibility, elasticity, and resiliency of the resulting foam. The surfactant may be either a single surfactant or a multi-surfactant system. The foam possesses a number of qualities, such as softness and strength, which render the foam particularly suitable for use in a variety of personal care products, medical products, and the like.

1 - 39 . (canceled) 
     
     
         40 . A thermoplastic absorbent foam, comprising:
 a base resin;   a surfactant;   about 5% to about 50% by weight of a thermoplastic elastomer, wherein the thermoplastic elastomer is selected from the group consisting of styrene-isoprene-styrene (SIS), styrene-butadiene-styrene (SBS), styrene-isoprene-butadiene-styrene (SIBS), styrene-ethylene/butylene-styrene (SEBS), styrene-ethylene/propylene-styrene (SEPS), hydrogenated butadiene-isoprene-butadiene block copolymers, stereoblock polypropylenes; ethylene-propylene-diene terpolymer (EPDM), ethylene-propylene random copolymers (EPM), ethylene propylene rubbers (EPR), thermoplastic polyether ester elastomers, polyamide thermoplastic elastomers; thermoplastic polyurethanes; and combinations thereof; and   about 0.5% to about 10% by weight of a plasticizing agent;   the foam having an open cell content of 50% or greater.   
     
     
         41 . The thermoplastic absorbent foam of  claim 40 , wherein the base resin comprises at least one of the group consisting of polystyrene, styrene copolymers, polyolefins, polyesters, and combinations thereof. 
     
     
         42 . The thermoplastic absorbent foam of  claim 40 , wherein the surfactant comprises an anionic surfactant. 
     
     
         43 . The thermoplastic absorbent foam of  claim 40 , wherein the plasticizing agent comprises at least one of the group consisting of polyethylene; ethylene vinyl acetate; mineral oil, palm oil, waxes, naphthalene oil, paraffin oil, acetyl tributyl citrate; acetyl triethyl citrate; p-tertbutylphenyl salicylate; butyl stearate; butylphthalyl butyl glycolate; dibutyl sebacate; di-(2-ethylhexyl) phthalate; diethyl phthalate; diisobutyl adipate; diisooctyl phthalate; diphenyl-2-ethylhexyl phosphate; epoxidized soybean oil; ethylphthalyl ethyl glycolate; glycerol monooleate; monoisopropyl citrate; mono-, di-, and tristearyl citrate; triacetin (glycerol triacetate); triethyl citrate; 3-(2-xenoyl)-1,2-epoxypropane; and combinations thereof. 
     
     
         44 . The thermoplastic absorbent foam of  claim 40 , wherein the plasticizing agent comprises a thermoplastic elastomer. 
     
     
         45 . The thermoplastic absorbent foam of  claim 40 , wherein the foam has a fluid intake flux of about 0.15 ml/sec/cm 2  or greater upon the first insult, about 0.15 ml/sec/cm 2  or greater upon the second insult, and about 0.15 ml/sec/cm 2  or greater upon the third insult. 
     
     
         46 . The thermoplastic absorbent foam of  claim 40 , wherein the foam has a cross-direction trap tear strength of about 200 grams or greater and a machine-direction trap tear strength of about 400 grams or greater. 
     
     
         47 . The thermoplastic absorbent foam of  claim 40 , wherein the foam has a peak load edge compression of about 1000 grams or less. 
     
     
         48 . The thermoplastic absorbent foam of  claim 40 , wherein the foam has a compression resistance of about 20% compression set or less. 
     
     
         49 . The thermoplastic absorbent foam of  claim 40 , wherein the foam has a vertical wicking height of about 5 cm or greater. 
     
     
         50 . The thermoplastic absorbent foam of  claim 40 , wherein the bending modulus is less than about 4000 KPa at 1 mm deflection. 
     
     
         51 . The thermoplastic absorbent foam of  claim 40 , wherein the bending modulus is less than about 2000 KPa at 1 mm deflection. 
     
     
         52 . An absorbent article comprising the thermoplastic absorbent foam of  claim 40 . 
     
     
         53 . The absorbent article of  claim 52 , wherein the article is selected from the group consisting of personal care articles, household/industrial articles and health/medical articles. 
     
     
         54 . A roll product comprising a foam sheet wound into a roll, wherein the foam sheet comprises the thermoplastic absorbent foam of  claim 40 . 
     
     
         55 . A thermoplastic absorbent foam, comprising:
 a base resin;   a multi-surfactant system; and   a thermoplastic elastomer selected from the group consisting of styrene-isoprene-styrene (SIS), styrene-butadiene-styrene (SBS), styrene-isoprene-butadiene-styrene (SIBS), styrene-ethylene/butylene-styrene (SEBS), styrene-ethylene/propylene-styrene (SEPS), hydrogenated butadiene-isoprene-butadiene block copolymers, stereoblock polypropylenes; ethylene-propylene-diene terpolymer (EPDM), ethylene-propylene random copolymers (EPM), ethylene propylene rubbers (EPR), thermoplastic polyether ester elastomers, polyamide thermoplastic elastomers; thermoplastic polyurethanes; and combinations thereof;   the foam having an open cell content of 50% or greater.   
     
     
         56 . The thermoplastic absorbent foam of  claim 55 , wherein the base resin comprises at least one of the group consisting of polystyrene, styrene copolymers, polyolefins, polyesters, and combinations thereof. 
     
     
         57 . The thermoplastic absorbent foam of  claim 55 , wherein the multi-surfactant system comprises an anionic surfactant. 
     
     
         58 . The thermoplastic absorbent foam of  claim 55  further comprising a plasticizing agent selected from at least one of the group consisting of polyethylene; ethylene vinyl acetate; mineral oil, palm oil, waxes, naphthalene oil, paraffin oil, acetyl tributyl citrate; acetyl triethyl citrate; p-tertbutylphenyl salicylate; butyl stearate; butylphthalyl butyl glycolate; dibutyl sebacate; di-(2-ethylhexyl) phthalate; diethyl phthalate; diisobutyl adipate; diisooctyl phthalate; diphenyl-2-ethylhexyl phosphate; epoxidized soybean oil; ethylphthalyl ethyl glycolate; glycerol monooleate; monoisopropyl citrate; mono-, di-, and tristearyl citrate; triacetin (glycerol triacetate); triethyl citrate; 3-(2-xenoyl)-1,2-epoxypropane; and combinations thereof. 
     
     
         59 . A thermoplastic absorbent foam, comprising:
 a base resin;   a multi-surfactant system;   about 5% to about 50% by weight of a thermoplastic elastomer, wherein the thermoplastic elastomer is selected from the group consisting of styrene-isoprene-styrene (SIS), styrene-butadiene-styrene (SBS), styrene-isoprene-butadiene-styrene (SIBS), styrene-ethylene/butylene-styrene (SEBS), styrene-ethylene/propylene-styrene (SEPS), hydrogenated butadiene-isoprene-butadiene block copolymers, stereoblock polypropylenes; ethylene-propylene-diene terpolymer (EPDM), ethylene-propylene random copolymers (EPM), ethylene propylene rubbers (EPR), thermoplastic polyether ester elastomers, polyamide thermoplastic elastomers; thermoplastic polyurethanes; and combinations thereof; and   about 0.5% to about 10% by weight of a plasticizing agent;   the foam having an open cell content of 50% or greater.