FIBER-CONTAINING ARTICLE AND METHOD OF MANUFACTURE
A fire resistance or acoustical absorbing article comprises a bast fiber component, a thermoplastic material 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 may 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 10-40 wt. % of a first fire retardant component mixed therein, said fiber component comprising about 1-50 weight percent thermoplastic material and about 50-99 weight percent bast fiber, wherein the fibrous mass has a coating of a second fire retardant component on exterior surfaces of the fibrous mass.
2 . The article of claim 1 wherein the thermoplastic material is polypropylene, polyethylene, polyesters, nylon, copolymers, or mixtures thereof.
3 . The article of claim 2 wherein the thermoplastic component is polypropylene.
4 . The article of claim 1 wherein the bast fibers are kenaf, jute, industrial hemp, sisal, flax, or mixtures thereof.
5 . The article of claim 4 wherein the bast fibers comprise kenaf.
6 . The article of claim 1 wherein the first fire retardant component is borates, polyborates, boric acid, borax, phosphates or mixtures thereof.
7 . The article of claim 6 wherein the first fire retardant component comprises sodium polyborate.
8 . The article of claim 1 wherein the second fire retardant component 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 the fibrous mass;
(c) heating the 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 the shaped article.
10 . The method of claim 9 wherein the fibrous mass comprises about 1-50 weight present thermoplastic material and about 50-99 weight percent natural fiber.
11 . The method of claim 9 wherein the bast fibers are kenaf, jute, industrial hemp, sisal, flax, or mixtures thereof.
12 . The method of claim 11 wherein the natural fibers comprise kenaf.
13 . The method of claim 9 wherein the thermoplastic material is fibers, bicomponent fibers, powder, or pellets.
14 . The method of claim 9 wherein the thermoplastic material is polypropylene, polyethylene, polyesters, nylon, copolymers, or mixtures thereof.
15 . The method of claim 14 wherein the thermoplastic material is polypropylene.
16 . The method of claim 9 wherein the first fire retardant is borates, polyborates, boric acid, borax, or phosphates.
17 . The method of claim 16 wherein the first fire retardant component comprises sodium polyborate.
18 . The method of claim 9 wherein the 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 set the second fire retardant component on the article.
20 . The method of claim 9 wherein the 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 the fibrous mass;
(c) applying a coating of a second fire retardant component to the fibrous mass, heating the fibrous mass; and
(d) compressing the fibrous mass to form a shaped article.
22 . A structure comprising the fire-resistant article of claim 1 .
23 . An acoustical absorbing structure comprising the fire-resistant article of claim 1.