Patent ID: 7556757
Filing Date: 2009-07-07
Classification: B29B,B29C,C08L,C09K,Y02A

Abstract:
1. A method for preparing a biodegradable composition for the preparation of table-ware, mulching film and package, the method comprising: (1) treating one or more plant wastes selected from the group consisting of sugar cane residue, peanut shell, dry pine needle, rice husk, millet bran and soybean shell soaked in a 0.2-1.0% by weight of sulfuric acid or hydrochloric acid solution for 2-10 hours to degrease and modify and to wash, and then drying the same to let it have a water content of less than 10%; mixing the obtained plant wastes with starch, sorbitol, polypropylene, and polyethylene, and pulverizing the obtained mixture to obtain a powder with a particle size of larger than 70 mesh; mixing the obtained powder with calcium carbonate, stearic acid, stearate, coupling agent, defoamer, glycerine or epoxidized soybean oil and photosensitizer homogeneously; and (2) blending the mixture obtained in step (1) in a double-screw extruder at a temperature of 160-180° C. to obtain the biodegradable composition which comprises 2-6% by weight of starch, 35-45% by weight of plant wastes, 20-30% by weight of calcium carbonate; 2-7% by weight of sorbitol, 7-13% by weight of polypropylene, 2-5% by weight of polyethylene, 2-6% by weight of coupling agent, 1-2% by weight of defoamer, 2-5% by weight of stearic acid, 2-6% by weight of stearate, 3-6% by weight of glycerine or epoxidized soybean oil, and 60-100 ppm photosensitizer.