Foam manufacturing method, and foam manufactured thereby

Abstract

It is an object of the present invention to provide a method for manufacturing a high-quality foam that can be produced stably on an industrial scale and that affords excellent thermal insulation as a foam with thin cell membranes, which method ensures uniform molten mixture fluidity, which is an essential condition for achieving consistent foam quality, in the manufacture of a foam by mixing starch as one molten polymer compound with another polymer compound having a different melt viscosity, and to provide a foam manufactured by this method. Water is added to and mixed with a plant-derived fibrous material and starch to manufacture a foam of a plastic resin containing as compositional components starch and a plant-derived fibrous material such as pulverized paper, pulverized wood, or the like. A foam is manufactured by a method comprising a step of producing pellets in which starch molecular spheres are agglomerated to each other or to the plant-derived fibrous material without the starch undergoing agglutination, and the step of foaming the pellets by mixing them with a plastic resin, and included in between these two steps is a step of drying the pellets at a temperature not higher than the starch agglutination temperature.

1 - 20 . (canceled)  
     
     
         21 . A foam, manufactured by the foam manufacturing method, for manufacturing a foam of a plastic resin containing, as compositional components, starch and a plant-derived fibrous material such as pulverized paper, pulverized wood or the like, comprising the steps of: 
 adding water to the plant-derived fibrous material and starch and mixing the components to produce pellets in which starch molecular spheres are agglomerated to each other or to the plant-derived fibrous material without the starch undergoing agglutination; and    foaming said pellets by mixing the pellets with a plastic resin, and the method further comprising, between these two steps, a step of drying the pellets at a temperature not higher than the starch agglutination temperature, wherein the plant-derived fibrous material component accounts for 20 to 80 wt %, the starch component for 10 to 30 wt %, and the plastic resin component for 10 to 50 wt %.    
     
     
         22 . A foam, manufactured by the foam manufacturing method, for manufacturing a foam of a plastic resin containing, as compositional components, starch and a plant-derived fibrous material such as pulverized paper, pulverized wood or the like, comprising the steps of: 
 adding water to the plant-derived fibrous material and starch and mixing the components to produce pellets in which starch molecular spheres are agglomerated to each other or to the plant-derived fibrous material without the starch undergoing agglutination; and    foaming said pellets by mixing them with a plastic resin, and    the method further comprising, between these two steps, a step of drying the pellets at a temperature not higher than the starch agglutination temperature, the pellets being dried for a relatively long time at a low temperature of 50° C. or lower, wherein the plant-derived fibrous material component accounts for 20 to 80 wt %, the starch component for 10 to 30 wt %, and the plastic resin component for 10 to 50 wt %.    
     
     
         23 . A foam, manufactured by the foam manufacturing method, for manufacturing a foam of a plastic resin containing, as compositional components, starch and a plant-derived fibrous material such as pulverized paper, pulverized wood or the like, comprising the steps of: 
 adding water to the plant-derived fibrous material and starch and mixing the components to produce pellets in which starch molecular spheres are agglomerated to each other or to the plant-derived fibrous material without the starch undergoing agglutination; and    foaming said pellets by mixing them with a plastic resin, and    the method further comprising, between these two steps, a step of drying the pellets at a temperature not higher than the starch agglutination temperature, the plant-derived fibrous material comprising pulverized paper as a compositional component, and the plastic resin comprising a polyolefin resin such as a polypropylene resin or polyethylene resin as a compositional component, wherein the plant-derived fibrous material component accounts for 20 to 80 wt %, the starch component for 10 to 30 wt %, and the plastic resin component for 10 to 50 wt %.    
     
     
         24 . A foam, manufactured by the foam manufacturing method, for manufacturing a foam of a plastic resin containing, as compositional components, starch and a plant-derived fibrous material such as pulverized paper, pulverized wood or the like, comprising the steps of: 
 adding water to the plant-derived fibrous material and starch and mixing the components to produce pellets in which starch molecular spheres are agglomerated to each other or to the plant-derived fibrous material without the starch undergoing agglutination; and    foaming said pellets by mixing them with a plastic resin, and    the method further comprising, between these two steps, a step of drying the pellets at a temperature not higher than the starch agglutination temperature, the pellets being dried for a relatively long time at a low temperature of 50° C. or lower, the plant-derived fibrous material comprising pulverized paper as a compositional component, and the plastic resin comprising a polyolefin resin such as a polypropylene resin or polyethylene resin as a compositional component, wherein the plant-derived fibrous material component accounts for 20 to 80 wt %, the starch component for 10 to 30 wt %, and the plastic resin component for 10 to 50 wt %.    
     
     
         25 . A foam, manufactured by the foam manufacturing method, for manufacturing a foam of a plastic resin containing, as compositional components, starch and a plant-derived fibrous material such as pulverized paper, pulverized wood or the like, comprising the steps of: 
 adding water to the plant-derived fibrous material and starch and mixing the components to produce pellets in which starch molecular spheres are agglomerated to each other or to the plant-derived fibrous material without the starch undergoing agglutination; and    foaming said pellets by mixing them with a plastic resin, and    the method further comprising, between these two steps, a step of drying the pellets at a temperature not higher than the starch agglutination temperature, the plant-derived fibrous material comprising pulverized paper as a compositional component, and the plastic resin comprising a polyolefin resin such as a polypropylene resin or polyethylene resin as a compositional component, wherein the pulverized paper is made from high-grade waste paper, or from printing scraps or waste of postal cards, stamps such as postage stamps, currency, and so forth, wherein the plant-derived fibrous material component accounts for 20 to 80 wt %, the starch component for 10 to 30 wt %, and the plastic resin component for 10 to 50 wt %.    
     
     
         26 . A foam, manufactured by the foam manufacturing method, for manufacturing a foam of a plastic resin containing, as compositional components, starch and a plant-derived fibrous material such as pulverized paper, pulverized wood or the like, comprising the steps of: 
 adding water to the plant-derived fibrous material and starch and mixing the components to produce pellets in which starch molecular spheres are agglomerated to each other or to the plant-derived fibrous material without the starch undergoing agglutination; and    foaming said pellets by mixing them with a plastic resin, and    the method further comprising, between these two steps, a step of drying the pellets at a temperature not higher than the starch agglutination temperature, the pellets being dried for a relatively long time at a low temperature of 50° C. or lower, the plant-derived fibrous material comprising pulverized paper as a compositional component, and the plastic resin comprising a polyolefin resin such as a polypropylene resin or polyethylene resin as a compositional component, wherein the pulverized paper is made from high-grade waste paper, or from printing scraps or waste of postal cards, stamps such as postage stamps, currency, and so forth, wherein the plant-derived fibrous material component accounts for 20 to 80 wt %, the starch component for 10 to 30 wt %, and the plastic resin component for 10 to 50 wt %.    
     
     
         27 . A foam, manufactured by the foam manufacturing method, for manufacturing a foam of a plastic resin containing, as compositional components, starch and a plant-derived fibrous material such as pulverized paper, pulverized wood or the like, comprising the steps of: 
 adding water to the plant-derived fibrous material and starch and mixing the components to produce pellets in which starch molecular spheres are agglomerated to each other or to the plant-derived fibrous material without the starch undergoing agglutination; and    foaming said pellets by mixing them with a plastic resin, and    the method further comprising, between these two steps, a step of drying the pellets at a temperature not higher than the starch agglutination temperature, the plant-derived fibrous material comprising pulverized wood as a compositional component, and the plastic resin comprising a polyolefin resin such as a polypropylene resin or polyethylene resin as a compositional component, wherein the plant-derived fibrous material component accounts for 20 to 80 wt %, the starch component for 10 to 30 wt %, and the plastic resin component for 10 to 50 wt %.    
     
     
         28 . A foam, manufactured by the foam manufacturing method, for manufacturing a foam of a plastic resin containing, as compositional components, starch and a plant-derived fibrous material such as pulverized paper, pulverized wood or the like, comprising the steps of: 
 adding water to the plant-derived fibrous material and starch and mixing the components to produce pellets in which starch molecular spheres are agglomerated to each other or to the plant-derived fibrous material without the starch undergoing agglutination; and    foaming said pellets by mixing them with a plastic resin, and    the method further comprising, between these two steps, a step of drying the pellets at a temperature not higher than the starch agglutination temperature, the pellets being dried for a relatively long time at a low temperature of 50° C. or lower, the plant-derived fibrous material comprising pulverized wood as a compositional component, and the plastic resin comprising a polyolefin resin such as a polypropylene resin or polyethylene resin as a compositional component, wherein the plant-derived fibrous material component accounts for 20 to 80 wt %, the starch component for 10 to 30 wt %, and the plastic resin component for 10 to 50 wt %.    
     
     
         29 . A foam, manufactured by the foam manufacturing method, for manufacturing a foam of a plastic resin containing, as compositional components, starch and a plant-derived fibrous material such as pulverized paper, pulverized wood or the like, comprising the steps of: 
 adding water to the plant-derived fibrous material and starch and mixing the components to produce pellets in which starch molecular spheres are agglomerated to each other or to the plant-derived fibrous material without the starch undergoing agglutination; and    foaming said pellets by mixing them with a plastic resin, and    the method further comprising, between these two steps, a step of drying the pellets at a temperature not higher than the starch agglutination temperature, the plant-derived fibrous material comprising pulverized wood as a compositional component, and the plastic resin comprising a polyolefin resin such as a polypropylene resin or polyethylene resin as a compositional component, wherein the pulverized wood is of reed or the like, wherein the plant-derived fibrous material component accounts for 20 to 80 wt %, the starch component for 10 to 30 wt %, and the plastic resin component for 10 to 50 wt %.    
     
     
         30 . A foam, manufactured by the foam manufacturing method, for manufacturing a foam of a plastic resin containing, as compositional components, starch and a plant-derived fibrous material such as pulverized paper, pulverized wood or the like, comprising the steps of: 
 adding water to the plant-derived fibrous material and starch and mixing the components to produce pellets in which starch molecular spheres are agglomerated to each other or to the plant-derived fibrous material without the starch undergoing agglutination; and    foaming said pellets by mixing them with a plastic resin, and    the method further comprising, between these two steps, a step of drying the pellets at a temperature not higher than the starch agglutination temperature, the pellets being dried for a relatively long time at a low temperature of 50° C. or lower, the plant-derived fibrous material comprising pulverized wood as a compositional component, and the plastic resin comprising a polyolefin resin such as a polypropylene resin or polyethylene resin as a compositional component, wherein the pulverized wood is of reed or the like, wherein the plant-derived fibrous material component accounts for 20 to 80 wt %, the starch component for 10 to 30 wt %, and the plastic resin component for 10 to 50 wt %.