Cushion material formed of spring-structured resin-molded product, manufacturing method for the cushion material, and mold used for the manufacturing method

Abstract

There is provided a method for producing a cushion material composed of a resin molded article with a spring structure which is so moldable as to allow the mold take any shape and size, is cheap, and resistant to collapsing, does not cause fatigue even after prolonged use, and has high shock absorbing capability and load capacity, and thus suitably used as a material of any supports on which one can sit, rest or mount such as seats of automotive vehicles, motor cycles, bicycles, electric trains, and aircraft, saddles for horse riding, chairs, sofas and beds, and a method for producing a cushion material requiring only a low cost for its disposal.

1 . A method for producing a cushion material composed of a resin molded article having a spring structure, comprising the steps of: 
 forming a three-dimensional structure with voids at a predetermined bulk density by contacting, entwining, and gathering ad] acent ones of random loops or curls of solid and/or hollow continuous filaments and/or short filaments made from a thermoplastic resin;    heating a male die or a female die, or a female die and/or the three-dimensional structure to a temperature sufficiently high to soften the three-dimensional structure;    allowing the male die to intimately contact with the female die so as to tightly compress the three-dimensional structure; and    hardening the three-dimensional structure by cooling.    
     
     
         2 . A method as described in  claim 1  for producing a cushion material composed of a resin molded article having a spring structure wherein: 
 superfluous edges protruded from the three-dimensional structure into the stroke between the two mating dies are cut with a heat cutter so that the edges are cut out and open ends of edge filaments are fused together.    
     
     
         3 . A method as described in  claim 1  for producing a cushion material composed of a resin molded article having a spring structure wherein: 
 a base to which the resin molded article with a spring structure is attached serves as a male die, and the male die is allowed to intimately contact with a female die so as to tightly compress the three-dimensional structure; and    the three-dimensional structure is hardened by cooling.    
     
     
         4 . A cushion material composed of a resin molded article having a spring structure obtained by overlapping two or more layers of sheets each comprising a three-dimensional structure having a same or different spring property, wherein: 
 the three-dimensional structure is formed by contacting, entwining, and gathering adjacent ones of random loops or curls of solid and/or hollow continuous filaments and/or short filaments made from a thermoplastic resin; and    the three-dimensional structure is heated in a male die or in a female die to a temperature sufficiently high to soften it, compressed via closure of the two mating dies, and allowed to harden by cooling.    
     
     
         5 . A cushion material as described in  claim 4  composed of a resin molded article having a spring structure wherein the spring property is determined by the density, material and/or filament diameter of the three-dimensional structure.  
     
     
         6 . A cushion material as described in  claim 1  composed of a resin molded article having a spring structure wherein the volume of the resin molded article with a spring structure can be altered by adjusting stroke of the male die when the female die has a deeply set receptive base.  
     
     
         7 . A cushion material as described in  claim 1  composed of a resin molded article having a spring structure wherein, out of the two mating dies, at least the female die is made from concrete.  
     
     
         8 . A concrete-made female die used for molding a resin molded article with a spring structure which is obtained by preparing a framework according to a master female die effective for molding a resin molded article with a spring structure, pouring concrete paste into the space within the framework, and allowing the concrete paste to harden.  
     
     
         9 . A cushion material as described in  claim 1  composed of a resin molded article having a spring structure wherein the vertical movement of at least one of the two mating dies is achieved by a pantograph jack.  
     
     
         10 . A cushion material composed of a resin molded article having a spring structure comprising a three-dimensional structure, wherein: 
 the three-dimensional structure is formed by contacting, entwining, and gathering adjacent ones of random loops or curls of solid and/or hollow continuous filaments and/or short filaments made from a thermoplastic resin; and    the three-dimensional structure has, on both its top and bottom surfaces, two or more bulges formed on predetermined linear areas by stitching the boundaries of each area using a thread of a thermoplastic resin, and shortening the thread by pressure.    
     
     
         11 . A method for producing a cushion material composed of a resin molded article having a spring structure, comprising the steps of: 
 extruding a melt of a thermoplastic resin into filaments and contacting, entwining, and gathering adjacent ones of random loops or curls of continuous filaments, thereby forming a three-dimensional structure containing voids at a predetermined bulk density;    cutting the periphery of the three-dimensional structure or a resin molded article with a spring structure to give a U- or V-shaped profile, and stitching the thus formed edges with a thread of a thermoplastic resin; and    stitching with a thread of a thermoplastic resin the boundaries of predetermined linear areas on the top and bottom surfaces of the three-dimensional structure, and shortening the thread by pressure.    
     
     
         12 . A method as described in  claim 11  for producing a cushion material composed of a resin molded article having a spring structure, comprising the steps of: 
 placing the three-dimensional structure on a female die;    heating the female die and/or the three-dimensional structure to a temperature sufficiently high to soften the three-dimensional structure;    allowing a male die to intimately contact with the female die so as to tightly compress the three-dimensional structure;    cooling the three-dimensional structure to confer a constant spring property thereto; and    stitching with a thread of a thermoplastic resin the boundaries of predetermined linear areas on the top and bottom surfaces of the three-dimensional structure, and shortening the thread by pressure.