Sportsboard structures

Abstract

A sports board that includes an elongate, water impervious, thermoplastic foam core having an upper surface and an under surface; an upper layer covering at least a portion of the upper surface; and an under layer covering at least a portion of the under surface. The foam core is made of a foamed material having a water absorption (measured according to ASTM C-272) of less than 2 volume percent.

1 - 25 . (canceled) 
     
     
         26 . A method of making a surfboard comprising:
 a) producing interpolymer particles of a polyolefin and in situ polymerized vinyl aromatic monomers by suspending polyolefin particles and vinyl aromatic monomers in an aqueous suspension and polymerizing the monomers inside the polyolefin particles;   b) producing expandable interpolymer particles by impregnating the interpolymer particles with a blowing agent and optionally a plasticizer;   c) expanding and molding the expandable interpolymer particles into a foam core shape, having an upper surface and an under surface, by applying steam to expand the particles and cause fusion between the particles;   d) optionally applying a sealant to the upper surface or under surface; and   e) applying an upper layer covering to at least a portion of the upper surface or applying an under layer covering to at least a portion of the under surface;   wherein the interpolymer particles comprise from 20% to 80% by weight of the polyolefin and 20% to 80% by weight of the polymerized vinyl aromatic monomers.   
     
     
         27 . The method according to  claim 26 , wherein the foam core part comprises expanded and fused interpolymer particles with a skin formed on at least a portion of the upper surface or the under surface. 
     
     
         28 . The method according to  claim 26 , wherein the vinyl aromatic monomers comprise styrene. 
     
     
         29 . The method according to  claim 26 , wherein the polyolefin particles comprise polymers selected from the group consisting of polypropylene, polyethylene, ethylene vinyl acetate copolymer; ethylene/propylene copolymer; blends of polyethylene and polypropylene; blends of polyethylene and an ethylene/vinyl acetate copolymer; blends of polyethylene and an ethylene/propylene copolymer, ethylene-butyl acrylate copolymer and ethylene-methyl methacrylate copolymer. 
     
     
         30 . The method according to  claim 26 , wherein the blowing agent is selected from the group consisting of butanes, pentanes, hexanes, and halogenated hydrocarbons. 
     
     
         31 . The method according to  claim 26 , wherein the plasticizer is selected from the group consisting of benzene, toluene, limonene, linear, branched or cyclic C 5  to C 20  alkanes, white oil, linear, branched or cyclic C 1  to C 20  dialkylphthalates, styrene, oligomers of styrene, oligomers of (meth)acrylates having a glass transition temperature less than polystyrene, and combinations thereof. 
     
     
         32 . The method according to  claim 26 , comprising:
 b-1) pre-expanding the expandable interpolymer particles to form pre-expanded interpolymer particles; and   b-2) ageing the pre-expanded interpolymer particles for four to 48 hours.   
     
     
         33 . The method according to  claim 26 , wherein the expanding and molding the expandable interpolymer particles into a foam core shape is carried out in a steam molding press. 
     
     
         34 . The method according to  claim 26 , wherein the sealant agent is selected from the group consisting of ethylene-vinyl acetate copolymers, ethylene-vinyl alcohol copolymers, ethylene-acrylic acid copolymers, styrene-butadiene polymers, styrene-isoprene polymers, styrene-butadiene-styrene block polymers, styrene-isoprene-styrene block polymers, hydrogenated resins thereof, joint compound, gypsum paste, polyurethanes, polypropylene, and polyethylene. 
     
     
         35 . The method according to  claim 26 , wherein the sealant comprises a thermoplastic polyolefin; a thermoplastic styrenic polymer; and a styrenic block copolymer. 
     
     
         36 . The method according to  claim 26 , wherein the upper layer covering or under layer covering comprises fibrous mats or fibrous fabric. 
     
     
         37 . The method according to  claim 36 , wherein the fibrous mats or fibrous fabric comprise fibers selected from the group consisting of glass fibers, aramide fibers, polyamide fibers, carbon fibers, silicon carbide fibers, composite fibers, metal fibers, fiberglass, and combinations thereof. 
     
     
         38 . The method according to  claim 26 , comprising:
 e-1) applying one or more fibrous layers to the upper surface or the under surface a of the foam core shape;   e-2) applying a laminating resin to the one or more fibrous layers;   e-3) curing the laminating resin such that it is allowed to cure and harden, securing the one or more fibrous layers to the foam core shape.   
     
     
         39 . The method according to  claim 38 , wherein the laminating resin comprises a resin system, a cure catalyst, and optionally filler materials. 
     
     
         40 . The method according to  claim 39 , wherein the laminating resin comprises a resin selected from the group consisting of unsaturated polyester resins, saturated polyester resins, epoxy resins, phenol-formaldehyde resins, melamine-formaldehyde resins, urea-formaldehyde resins, unsaturated polyesteramide resins, vinyl ester resins, polyimide resins, poly amide-imide resins, unsaturated (meth)acrylic resins, and acrylic-urethane resins. 
     
     
         41 . The method according to  claim 26 , comprising:
 e-1) applying one or more fibrous layers to the upper surface or the under surface a of the foam core shape;   e-2) applying a laminating resin to the one or more fibrous layers to provide a treated foam core shape;   e-3) inserting the treated foam core shape into a lower mold segment of a mold press;   e-4) closing the mold press;   e-5) applying pressure in the mold press to cause the laminating resin to be completely distributed in the space between the foam core and the one or more fibrous layers;   e-6) curing the treated foam core shape to provide a closed fiber-reinforced shell in intimate contact with the foam core shape.   
     
     
         42 . The method according to  claim 41 , wherein the laminating resin comprises a resin system, a cure catalyst, and optionally filler materials. 
     
     
         43 . The method according to  claim 42 , wherein the laminating resin comprises a resin selected from the group consisting of unsaturated polyester resins, saturated polyester resins, epoxy resins, phenol-formaldehyde resins, melamine-formaldehyde resins, urea-formaldehyde resins, unsaturated polyesteramide resins, vinyl ester resins, polyimide resins, poly amide-imide resins, unsaturated (meth)acrylic resins, and acrylic-urethane resins. 
     
     
         44 . The method according to  claim 26 , wherein the foam core shape has a flexural strength at 5% strain of at least 60 psi at a molded density of about 2.25 lb/ft 3 . 
     
     
         45 . The method according to  claim 26 , wherein the foam core shape has a tensile strength of at least 75 psi at a molded density of about 2.25 lb/ft 3 . 
     
     
         46 . The method according to  claim 26 , wherein the upper layer covering or under layer covering comprise one or more polyolefins. 
     
     
         47 . The method according to  claim 26 , wherein the foam core shape comprises one or more axial or parabolic stringers. 
     
     
         48 . The method according to  claim 26 , wherein the surfboard comprises one or more fins secured to and extending from the under layer covering. 
     
     
         49 . The method according to  claim 26 , wherein the foam core part has a water absorption of less than 2 volume percent. 
     
     
         50 . A surfboard board made according to the method of  claim 26 .