Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
2001-11-16
2003-11-25
Seidleck, James J. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
Reexamination Certificate
active
06653364
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a hydrolyzable and biodegradable resin composition in consideration of the global environment and more particularly relates to a decomposable resin composition that has a low impact on the environmental and a method of treating the resin composition for lowering the environmental impact.
2. Related Background Art
In the past, humans successively produced useful domestic and industrial materials by employing coal chemical technologies and then petrochemical technologies. In particular, polymer materials may be symbolic examples. There have been produced useful resins including plastic materials such as polyethylene, polypropylene and polyvinyl chloride and rubbers such as polyisoprene and polybutadiene. Further, recently, resin materials having particularly excellent characteristics have been developed, including polyimide resins, which have heat and impact resistance, and full-aromatic liquid crystal polymers.
However, these resins are not biodegradable and remain unchanged in the environment for long after being discarded, imposing a significant, negative burden on the global environment. The waste from industries and domestic life has become a serious social problem. Today, there is an increased expectation for materials and products to be environmentally friendly. At the same time, it is preferable that these products and materials be manufactured with a minimal possible reliance on natural resources.
For such a purpose, biodegradable polymers that are easily decomposed in the environment have been developed. A substantial object is to obtain a resin that satisfies contradicting properties such as stability during use and quick decomposition when discarded. Further, based on the purpose, the decomposition speed itself is required to be controlled.
Consequently, the purpose of the present invention is to provide a decomposable resin composition, which is stable at the time of use, quickly decomposed when discarded and whose decomposition speed can be controlled.
SUMMARY OF THE INVENTION
The inventor of the present invention conducted an extensive investigation in order to solve the problem and found that the above purpose can be achieved by mixing a compound capable of generating an acid or a base by light irradiation or heating at a desired time with a decomposable resin and then generating an acid or a base in the decomposable resin by carrying out light irradiation and/or heat treatment at the desired time so as to promote the decomposition of the resin and thus achieved the invention.
The present invention includes a resin composition comprising, in a hydrolyzable and biodegradable resin, an agent generating an acid upon exposure to light and/or an agent generating a base upon exposure to light.
Further, the present invention provides a resin composition comprising, in a hydrolyzable and biodegradable resin, an agent generating an acid upon exposure to heat and/or an agent generating a base upon exposure to heat.
Further, the present invention provides a resin composition comprising, in a hydrolyzable and biodegradable resin, an agent generating an acid upon exposure to light and/or an agent generating a base upon exposure to light together with an agent generating an acid upon exposure to heating and/or an agent generating a base by heating.
Further, the present invention provides a method of producing a resin composition comprising the steps of: providing a resin composition comprising, in a hydrolyzable and biodegradable resin, an agent generating an acid upon exposure to light and/or an agent generating a base upon exposure to light; subjecting the resin composition to light irradiation and/or heat treatment to decompose the resin composition to monomers; polymerizing the monomers to produce a decomposable resin; and mixing compounds generating an acid or a base by light irradiation or heating with the decomposable resin.
Further, the present invention provides a method of treating a resin composition comprising the steps of: providing the resin composition comprising, in a hydrolyzable and biodegradable resin, an agent generating an acid upon exposure to light and/or an agent generating a base upon exposure to light; and subjecting the resin composition to light irradiation.
Further, the present invention provides a method of treating a resin composition comprising the steps of: providing the resin composition comprising, in a hydrolyzable and biodegradable resin, an agent generating an acid upon exposure to light and/or an agent generating a base upon exposure to light; subjecting the resin composition to light irradiation; and thereafter carrying out a heat treatment.
Further, the present invention provides a method of treating a resin composition comprising the steps of: providing the resin composition comprising, in a hydrolyzable and biodegradable resin, an agent generating an acid upon exposure to heat and/or an agent generating a base upon exposure to heat; and subjecting the resin composition to a heat treatment.
Further, the present invention provides a method of treating a resin composition comprising the steps of: providing the resin composition comprising, in a hydrolyzable and biodegradable resin, an agent generating an acid upon exposure to light and/or an agent generating a base upon exposure to light together with an agent generating an acid upon exposure to heat and/or an agent generating a base upon exposure to heat; and subjecting the resin composition to light irradiation and a heat treatment.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
As the decomposable resin to be employed in the present invention, usable are a wide range of well-known biodegradable, hydrolyzable polyesters. Especially preferable are polylactic acid, polylactic acid-aliphatic polyester copolymers and copolymers of saccharides and dicarboxylic acids having a structure defined as the following formula:
(Where (Sacch) denotes the saccharide structure and R denotes an alkylene group or a divalent aromatic ring.).
Monosaccharides are usable for the saccharide structure portion in the formula, including neutral saccharides such as D-glycelaldehyde, D-dihydroxyacetone, D-xylose, D-glucose, D-fructose, D-mannose, D-galactose and L-fucose; acidic saccharides such as D-glucuronic acid and L-iduronic acid; aminosaccharides such as D-glucosamine, D-galactosamine, N-acetylglucosamine, N-acetylgalactosamine and N-acetylmuramic acid; dialuric acid such as N-acetylneuraminic acid; glycitols such as glycerol and inositol; and disaccharides such as saccharose, maltose, lactose, cellobiose and trehalose. Further polysaccharides are usable such as amylose, cellulose, chitin, chitosan, hyaluronic acid, chondoroitin hexasulfuric acid, keratosulfuric acid and heparine.
On the other hand, R in the formula may preferably be an alkylene of 1 to 12 carbons or a divalent aromatic group, for example, phenylene or naphthylene. Examples of a dicarboxylic acid containing such groups are aliphatic dicarboxylic acids, such as malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid and 1,10-didecanedicarboxylic acid; and an aromatic dicarboxylic acid, such as terephthalic acid, isophthalic acid, orthophthalic acid and naphthalenedicarboxylic acid.
Among the polymers defined by the formula, especially preferable are polyesters represented by the following formula (II), such as polyesters produced from D-glucose and aliphatic dicarboxylic acids having 5 to 10 carbons and polyesters produced from compounds derived from D-glucose by substituting a hydroxyl group with an alkyl group, a hydroxyalkyl group and the like and aliphatic dicarboxylic acids having 5 to 10 carbons:
(Where R denotes an alkylene; R1, R2 and R3 separately denote hydrogen atom, an alkyl of 1to 10 carbons, or a hydroxyalkyl.).
Especially, in the case of using D-glucose in the portion of the saccharide structure, D-glucose can be obtained by decomposition of cellulose. From a v
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
McClendon Sanza L
Seidleck James J.
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