Foam cushion and method of making and using the same

Abstract

The present invention provides a foam cushion, a method of making the foam cushion, and a method of using the foam cushion. The foam cushion is formed from: (a) at least one of rubber and a resin; (b) a blowing agent; (c) a polymeric adhesion modifier; (d) a decomposition accelerating agent, and (e) a cross-linking agent.

1 . A method for manufacturing a foam cushion, the method comprising the steps of: 
 (a) contacting rubber, a resin, a blowing agent, a polymeric adhesion modifier, and a decomposition accelerating agent for about 8 minutes to about 20 minutes at about 110° C. to about 130° C. to form a first mixture;    (b) contacting the first mixture with a cross-linking agent for about 1 minute to about 5 minutes at about 110° C. to about 130° C. to form a second mixture;    (c) heating the second mixture at about 100° C. to about 120° C. until the second mixture becomes concentrated to about 20 mm thickness;    (d) spreading the second mixture to form a sheet;    (e) cooling the sheet to below about 80° C.;    (f) stacking a plurality of the sheets;    (g) contacting the plurality of sheets with a solution comprising a silicone-containing compound;    (h) pressing the plurality of the sheets for about 28 minutes to about 35 minutes at about 160° C. to about 175° C. to form a cooked stack;    (i) cutting, horizontally, a portion of the top of the cooked stack and removing that portion;    (j) cutting, horizontally, a portion of the bottom of the cooked stack and removing that portion;    (k) slicing the cooked stack into sliced pieces having a thickness of about 1 mm to about 20 mm;    (l) attaching two or more of the sliced pieces on an end-to-end basis; and    (m) rinsing, scrub washing, and drying the attached sliced pieces to provide the foam cushion.    
     
     
         2 . The method of  claim 1  wherein the rubber is synthetic rubber (SR).  
     
     
         3 . The method of  claim 2  wherein the synthetic rubber is a polybutadiene rubber (BR); a polyisoprene rubber (IR); a styrene-butadiene rubber (SBR); a nitrile rubber (NBR); a butyl rubber (IIR); an ethylene-propylene terpolymer (EPDM); a silicone rubber; a neoprene rubber; a polysulfide; a polyacrylate rubber; an epichlorohydrin rubber; a fluoroelastomer (FDM); a chloronated polyethylene (CSM); a halogenated butyl or bromobutyl (BIIR); a chlorinated polyethylene rubber (CPE); a polyurethane; a thermoplastic rubber; chlorinated natural rubber, cyclized rubber; or a combination thereof.  
     
     
         4 . The method of claim 1 wherein the rubber is natural rubber (NR).  
     
     
         5 . The method of  claim 4  wherein the natural rubber is obtained from the  Hevea brasiliensis  tree, the guayule bush  Parthenoim argentatum,  the  Sapotaceae tree,  or a combination thereof.  
     
     
         6 . The method of  claim 4  wherein the natural rubber is a latex grade.  
     
     
         7 . The method of  claim 4  wherein the natural rubber is a remilled grade.  
     
     
         8 . The method of  claim 4  wherein the natural rubber is technically-specified natural rubber (TSR), superior processing natural rubber (SP), technically classified natural rubber (TC), air-dried sheet natural rubber (ADS), skin natural rubber, deproteinized natural rubber (DPNR), oil-extended natural rubber (OENR), hevealplus MG natural rubber, epoxidized natural rubber, or a combination thereof.  
     
     
         9 . The method of  claim 4  wherein the natural rubber (NR) comprises cis-polyisoprene, trans-polyisoprene, or a combination thereof.  
     
     
         10 . The method of  claim 4  wherein the natural rubber (NR) comprises about 93 wt. % to about 95 wt. % of polyisoprene.  
     
     
         11 . The method of  claim 1  wherein the rubber is employed up to about 80 wt. % of the foam cushion.  
     
     
         12 . The method of  claim 1  wherein the rubber is employed in about 5 wt. % to about 12 wt. % of the foam cushion.  
     
     
         13 . The method of  claim 1  wherein the resin is a thermoplastic polymer, thermoplastic terpolymer, thermoplastic homopolymer, thermoplastic copolymer, or a combination thereof.  
     
     
         14 . The method of  claim 13  wherein the thermoplastic copolymer comprises an ethylene vinyl acetate (EVA), an ethylene propylene rubber, an ethylene methyl acrylate copolymer, an ethylene ethyl acrylate copolymer, an ethylene(meth)acrylate polymer, a polybutylene terephchalate (PBT) polymer, or a combination thereof.  
     
     
         15 . The method of  claim 13  wherein the thermoplastic homopolymer comprises a polyethylene, a chlorinated polyethylene, a metallocene polyethylene, a polypropylene, or a combination thereof.  
     
     
         16 . The method of  claim 13  wherein the thermoplastic terpolymer comprises a modified ethylene acrylate carbon monoxide terpolymer.  
     
     
         17 . The method of  claim 1  wherein the resin is an ethylene-vinyl acetate (EVA) copolymer.  
     
     
         18 . The method of  claim 17  wherein the ethylene-vinyl acetate copolymer comprises about 15 wt. % to about 75 wt. % vinyl acetate.  
     
     
         19 . The method of  claim 1  wherein the resin is employed up to about 95 wt. % of the foam cushion.  
     
     
         20 . The method of  claim 1  wherein the resin is employed in about 79 wt. % to about 83 wt. % of the foam cushion.  
     
     
         21 . The method of  claim 1  wherein the blowing agent is a (C 1 -C 12 )hydrocarbon, a (C 1 -C 12 )organohalogen, a (C 1 -C 12 )alcohol, a (C 1 -C 12 )ether, a (C 1 -C 12 )ester, a (C 1 -C 12 )amine, or a combination thereof.  
     
     
         22 . The method of  claim 21  wherein the (C 1 -C 12 )hydrocarbon is acetylene, propane, propene, butane, butene, butadiene, isobutane, isobutylene, cyclobutane, cyclopropane, ethane, methane, ethene, pentane, pentene, cyclopentane, pentene, pentadiene, hexane, cyclohexane, hexene, hexadiene, or a combination thereof.  
     
     
         23 . The method of  claim 1  wherein the blowing agent is ammonia, nitrogen, carbon dioxide, neon, helium, butane, isobutane, 1,1-difluoroethane, p,p′-oxybis(benzene)sulfonyl hydrazide, p-toluene sulfonyl hydrazide, p-toluene sulfonyl semicarbazide, 5-phenyltetrazole, ethyl-5-phenyltetrazole, dinitroso pentamethylenetetramine, acetone, azodicarbonamide (AC), dinitroso pentamethylene tetramine (DNPT), or a combination thereof.  
     
     
         24 . The method of  claim 1  wherein the blowing agent is azodicarbonamide.  
     
     
         25 . The method of  claim 1  wherein the blowing agent is employed in about 0.1 wt. % to about 10 wt. % of the foam cushion.  
     
     
         26 . The method of  claim 1  wherein the blowing agent is employed in about 3 wt. % to about 4.2 wt. % of the foam cushion.  
     
     
         27 . The method of  claim 1  wherein the polymeric adhesion modifier comprises an anhydride grafted polyolefin resin, a styrene maleic anhydride (SMA) copolymer, or a combination thereof.  
     
     
         28 . The method of  claim 27  wherein the anhydride is maleic anhydride.  
     
     
         29 . The method of  claim 1  wherein the polymeric adhesion modifier comprises an anhydride grafted polyolefin resin, wherein the polyolefin is selected from polyethylene, polypropylene, ethylene-propylene diene monomer, ethylene vinyl acetate (EVA), a copolymer thereof, or combinations thereof.  
     
     
         30 . The method of  claim 1  wherein the polymeric adhesion modifier is employed in about 0.5 wt. % to about 15.0 wt. % of the foam cushion.  
     
     
         31 . The method of  claim 1  wherein the polymeric adhesion modifier is employed in about 2.8 wt. % to about 3.9 wt. % of the foam cushion.  
     
     
         32 . The method of  claim 1  wherein the cross-linking agent is a radical generating species.  
     
     
         33 . The method of  claim 1  wherein the cross-linking agent is a peroxide.  
     
     
         34 . The method of  claim 33  wherein the peroxide is methylethylketone peroxide; dicumyl peroxide; 2,5-dimethyl-2,5-di(t-butylperoxy)hexane; 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane; 1,1-di-(t-butylperoxy)cyclohexane; 2,2′-bis(t-butylperoxy)diisopropylbenzene; 4,4′-bis(t-butylperoxy)butylvalerate; Ethyl 3,3-bis(t-butylperoxy)butyrate; t-butyl cumyl peroxide; di-[(t-butylperoxy)-isopropyl]benzene; t-butyl peroxide; 6,6,9,9-tetramethyl-3-methyl-3-n-butyl-1,2,4,5-tetraoxycyclononane; 6,6,9,9-tetramethyl-3-methyl-3-ethyl carbonylmethyl 1,2,4,5-tetraoxy-cyclononane; ethyl 3,3-di(t-butylperoxy)-butyrate; dibenzoyl peroxide; 2,4-dichlorobenzoyl peroxide; OO-t-butyl O-(2-ethylhexyl)mono peroxycarbonate; t-butyl cumyl peroxide; 2,5-dimethyl-2,5-di-(t-butylperoxy)-3-hexyne; or a combination thereof.  
     
     
         35 . The method of  claim 1  wherein the cross-linking agent is dicumyl peroxide.  
     
     
         36 . The method of  claim 1  wherein the cross-linking agent is employed in about 0.1 wt. % to about 2.0 wt. % of the foam cushion.  
     
     
         37 . The method of  claim 1  wherein the cross-linking agent is employed in about 0.5 wt. % to about 0.9 wt. % of the foam cushion.  
     
     
         38 . The method of  claim 1  wherein the cross-linking agent is triallyl cyanurate (TAC); triallyl isocyanurate (TAIC), triallyl phosphate (TAPA), ethylene glycol dimethacrylate; trimethylol propane trimethacrylate; allyl methacrylate; an alkoxysilanes; an oximesilane; or a combination thereof.  
     
     
         39 . The method of  claim 1  wherein the decomposition accelerating agent is at least one of an inorganic salt, a lead-containing compound, a metallic soap, a urea compound, and R 1 COOR 2 , wherein: 
 R 1  is (C 1 -C 20 )alkyl, (C 2 -C 20 )alkenyl, (C 1 -C 20 )alkynyl, aryl(C 1 -C 20 )alkyl, aryl(C 2 -C 20 )alkenyl, aryl(C 2 -C 20 )alkynyl, cycloalkyl(C 1 -C 20 )alkyl, cycloalkyl(C 2 -C 20 )alkenyl, or cycloalkyl(C 2 -C 20 )alkynyl; and p 1  R 2  is hydrogen, (C 1 -C 20 )alkyl, (C 2 -C 20 )alkenyl, (C 1 -C 20 )alkynyl, aryl(C 1 -C 20 )alkyl, aryl(C 2 -C 20 )alkenyl, aryl(C 2 -C 20 )alkynyl, cycloalkyl(C 1 -C 20 )alkyl, cycloalkyl(C 2 -C 20 )alkenyl, or cycloalkyl(C 2 -C 20 )alkynyl;    wherein any alkyl, alkenyl, alkynyl, cycloalkyl, or aryl is optionally substituted on carbon with one or more halo, nitro, cyano, (C 1 -C 20 )alkoxy, or trifluoromethyl;    or a pharmaceutically acceptable salt thereof.    
     
     
         40 . The method of  claim 1  wherein the decomposition accelerating agent is an inorganic salt.  
     
     
         41 . The method of  claim 1  wherein the decomposition accelerating agent is a carboxylic acid.  
     
     
         42 . The method of  claim 1  wherein the decomposition accelerating agent is an inorganic salt, a carboxylic acid, or a combination thereof.  
     
     
         43 . The method of  claim 1  wherein the decomposition accelerating agent is zinc oxide, tribasic lead sulfate, zinc stearate, lead stearate, stearic acid, or a combination thereof.  
     
     
         44 . The method of  claim 1  wherein the decomposition accelerating agent is a combination of zinc oxide and stearic acid.  
     
     
         45 . The method of  claim 1  wherein the decomposition accelerating agent is employed up to about 25 wt. % of the foam cushion.  
     
     
         46 . The method of  claim 1  wherein the decomposition accelerating agent is employed in about 1.5 wt. % to about 13.5 wt. % of the foam cushion.  
     
     
         47 . The method of  claim 1  further comprising adding to the first mixture or the second mixture at least one of a reinforcing agent, a filler, an extender, a placticizer, a vulcanization agent, an antioxidant, a fire retardant, an accelerator, a colorant, an electrically conductive material, and a stabilizer.  
     
     
         48 . The method of  claim 1  further comprising adding to the first mixture or the second mixture a cure retarder.  
     
     
         49 . The method of  claim 48  wherein the cure retarder is benzoic acid; phthalic anhydride; N-nitrosodiphenylamine; N-(cyclohexylthio)phthalimide, or a combination thereof.  
     
     
         50 . A method for manufacturing a foam cushion, the method comprising the steps of: 
 (a) contacting a natural rubber, an ethylene-vinyl acetate copolymer, azodicarbonamide, a polymeric adhesion modifier, and a combination of zinc oxide and stearic acid for about 8 minutes to about 20 minutes at about 110° C. to about 130° C. to form a first mixture;    (b) contacting the first mixture with dicumyl peroxide for about 1 minute to about 5 minutes at about 110° C. to about 130° C. to form a second mixture;    (c) heating the second mixture at about 100° C. to about 120° C. until the second mixture becomes concentrated to about 20 mm thickness;    (d) spreading the second mixture to form a sheet;    (e) cooling the sheet to below about 80° C.;    (f) stacking a plurality of the sheets;    (g) contacting the plurality of sheets with a solution comprising a silicone-containing compound;    (h) pressing the plurality of the sheets for about 28 minutes to about 35 minutes at about 160° C. to about 175° C. to form a cooked stack;    (i) cutting, horizontally, a portion of the top of the cooked stack and removing that portion;    (j) cutting, horizontally, a portion of the bottom of the cooked stack and removing that portion;    (k) slicing the cooked stack into sliced pieces having a thickness of about 1 mm to about 20 mm;    (l) attaching two or more of the sliced pieces on an end-to-end basis; and    (m) rinsing, scrub washing, and drying the attached sliced pieces to provide the foam cushion.    
     
     
         51 . The method of  claim 50  wherein the polymeric adhesion modifier comprises an anhydride grafted polyolefin resin, a styrene maleic anhydride copolymer, or a combination thereof.