Fire-resistant fiber-containing article and method of manufacture

Abstract

A fire resistance article comprises a bast fiber component, a thermoplastic component that acts as a binder, and a first fire retardant component, the article having a coating of a second fire retardant component, such that the article can be used in the manufacture of structures having a Class A fire resistance rating. In one method of manufacture, a fibrous mass of the bast fiber component and the thermoplastic binder has the first fire retardant dispersed therethrough, and is then heated, compressed to a desired thickness and density, and coated with the second fire retardant component.

1 . A fire-resistant article, said article comprising a fibrous mass having a fiber component and about 10-30 wt. % of a first fire retardant component mixed therein, said fiber component comprising about 1-50 weight percent thermoplastic and about 50-99 weight percent bast fiber, said fibrous mass having a coating of a second fire retardant component on the exterior surfaces thereof.  
   
   
       2 . The article of  claim 1  wherein said thermoplastic component is selected from the group consisting of polypropylene, polyethylene, polyesters, nylon, copolymers, and mixtures thereof.  
   
   
       3 . The article of  claim 2  wherein said thermoplastic is polypropylene.  
   
   
       4 . The article of  claim 1  wherein said bast fibers are selected from kenaf, jute, industrial hemp, sisal, flax, and mixtures thereof.  
   
   
       5 . The article of  claim 4  wherein said bast fibers comprise a mixture of kenaf and industrial hemp.  
   
   
       6 . The article of  claim 1  wherein said first fire retardant component is selected from the group consisting of borates, polyborates, boric acid, borax, phosphates and mixtures thereof.  
   
   
       7 . The article of  claim 6  wherein said first fire retardant component comprises sodium polyborate.  
   
   
       8 . The article of  claim 1  wherein said coating comprises sodium silicate.  
   
   
       9 . A method of making a fire-resistant article, said method comprising the steps of 
 (a) providing a fibrous mass comprising a mixture of thermoplastic material and bast fibers,    (b) dispersing a first fire retardant component in said fibrous mass,    (c) heating said fibrous mass to a temperature above the softening temperature of the thermoplastic material,    (d) compressing the mass to form a shaped article, and    (e) applying a coating of a second fire retardant component to said shaped article.    
   
   
       10 . The method of  claim 9  wherein said fibrous mass comprises about 1-50 weight present thermoplastic and about 50-99 weight percent natural fiber.  
   
   
       11 . The method of  claim 9  wherein said bast fibers are selected from kenaf, jute, industrial hemp, sisal, flax, and mixtures thereof.  
   
   
       12 . The method of  claim 11  wherein said natural fibers comprise a mixture of kenaf and industrial hemp fibers.  
   
   
       13 . The method of  claim 9  wherein said thermoplastic is in a form selected from the group consisting of fibers, bicomponent fibers, powder, and pellets.  
   
   
       14 . The method of  claim 9  wherein said thermoplastic component is selected from the group consisting of polypropylene, polyethylene, polyesters, nylon, copolymers, and mixtures thereof.  
   
   
       15 . The method of  claim 14  wherein said thermoplastic is polypropylene.  
   
   
       16 . The method of  claim 9  wherein said first fire retardant is selected from the group consisting of borates, polyborates, boric acid, borax, and phosphates.  
   
   
       17 . The method of  claim 16  wherein said first fire retardant component comprises sodium polyborate.  
   
   
       18 . The method of  claim 9  wherein said second fire retardant component is applied as a liquid composition.  
   
   
       19 . The method of  claim 9  comprising the further step of heating the article after the application of the second fire retardant component to allow said second fire retardant component to set as a coating on the article.  
   
   
       20 . The method of  claim 9  wherein said second fire retardant component comprises sodium silicate.  
   
   
       21 . A method of making a fire-resistant article, said method comprising the steps of 
 (a) providing a fibrous mass comprising a mixture of thermoplastic material and bast fibers,    (b) dispersing a first fire retardant component in said fibrous mass,    (c) applying a coating of a second fire retardant component to said fibrous mass,    (d) heating said fibrous mass, and    (e) compressing said fibrous mass to form a shaped article.    
   
   
       22 . A structure comprising the fire-resistant article of  claim 1.