Method for making a biodegradable fibrous material composition

1. Field of the Invention

This invention relates to a method for making a biodegradable fibrous material composition, more particularly to a method involving stirring a mixture of bamboo powder and water at a speed ranging from 1000-1800 rps/min.

2. Description of the Related Art

U.S. Pat. No. 7,132,463 discloses a conventional biodegradable composition containing 30-50 parts by weight of a fibrous powder, such as fibers derived from bamboo, wood, straw, sugarcane, woody stem, etc., and 5-50 parts by weight of acrylate copolymer. A biodegradable article, such as a food container, made from the conventional biodegradable composition is capable of improving water resistance and durability. However, when the bamboo fiber is used as the material for the fibrous powder in the biodegradable composition, problems, such as poor mixing with other materials, poor flowability, and undesired carbonization, occur.

Therefore, an object of the present invention is to provide a method for making a biodegradable fibrous material composition that can overcome the aforesaid drawbacks associated with the prior art.

According to the present invention, a method for making a biodegradable fibrous material composition comprises: (a) grinding raw bamboo into coarse raw bamboo particulates; (b) drying the raw bamboo particulates; (c) grinding the raw bamboo particulates into fine bamboo powder; (d) mixing the bamboo powder with water to result in a mixture; (e) stirring the mixture at a speed ranging from 1000 to 1800 rpm/min so as to soften fibers of the bamboo powder, which leads to formation of softened bamboo fibers; and (f) stirring a mixture of the softened bamboo fibers, a binder, a solidifying agent, a water repellent, starch and water at a speed ranging from 1000 to 1800 rpm/min so as to form the biodegradable fibrous material composition.

The preferred embodiment of the biodegradable fibrous material composition according to this invention includes: 35-55 wt % of a bamboo fiber; 25-50 wt % of a binder; 0.4-0.8 wt % of a solidifying agent; 0.2-0.6 wt % of a water repellent; 10-20 wt % of starch; and 0.5-1.5 wt % of water.

Preferably, the solidifying agent is selected from the group consisting of polyamide, epoxy chloropropane, a thermosetting resin, and combinations thereof. In this embodiment, the solidifying agent is a cationic intensifier, which is a thermosetting resin.

Preferably, the water repellent is selected from the group consisting of a cationic neutral sizing agent, and an acrylate polymer.

Preferably, the binder contains one of polyvinyl alcohol and polyvinyl acetate.

In this embodiment, the binder is made from a mixture of polyvinyl acetate and water. Alternatively, the binder can be made from a mixture of polyvinyl alcohol, water, starch and pulp.