JPH0593141A - Biodegradable plastic - Google Patents

Abstract

PURPOSE:To provide a plastic which is readily biodegradable and from which a small-sized molding of a complicated shape can be obtained. CONSTITUTION:Fine particles 2 of a biodegradable polymer, e.g. a natural polymer, are allowed to adhere to the surface of each of particles 1 of a microbiologically stable polymer, thereby to encapsulate each of the particles 1. A powder of the resulting microcapsules 3 is molded into a predetermined shape by, e.g. hot pressing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a biodegradable plastic which can be disintegrated by microorganisms in the ground when the used plastic is disposed of in a landfill.

[0002]

2. Description of the Related Art Most of used plastic products used for kitchen utensils and electric appliances are not reused, but can be used as they are with other wastes such as wood and kitchen waste in garbage dumps and landfills. Currently, it is abandoned. However, unlike plastic and wood waste, this plastic product is not decomposed by microorganisms, so its shape has been stopped for many years, which is one of the causes of shortage of landfills and environmental problems. Met.

Therefore, in recent years, biodegradable plastic materials which can be decomposed by microorganisms have been proposed. For example, a resin composition for molding proposed in Japanese Patent Publication No. 52-21530 is a thermoplastic resin which is not decomposed by microorganisms such as polyethylene, polypropylene and polyvinyl chloride, and a nutrient of microorganisms such as starch, lactose and carboxymethylcellulose. By mixing an organic substance as a source, the molding resin composition is decomposed after being discarded by microorganisms. In addition, JP-A-48-77
In Japanese Patent No. 436, a polyhydric alcohol-starch mixed melt is mixed with a resin such as polyvinyl chloride, polystyrene, and melanin so that the molding resin composition is decomposed by a microorganism after disposal.

[0004]

By the way, in the resin compositions for molding according to Japanese Patent Publication No. 52-21530 and Japanese Patent Application Laid-Open No. 48-77436, resins which are not decomposed by microorganisms and those which can be decomposed by microorganisms are possible. When the organic substances are mixed, as shown in FIG. 4, the mixture of the resin A, which is not decomposed by microorganisms, and the organic substance B, which can be decomposed by microorganisms, is non-uniform due to the difference in their specific gravities and the cause of the mixing means. Therefore, the surface quality and strength are deteriorated, and it is difficult to disassemble into pieces. That is, the portion where the organic substance B is aggregated is decomposed by microorganisms, but the portion where the resin A is aggregated is not decomposed by microorganisms, and the organic substance B is closed by the resin A. Since the microorganism was not transmitted to the portion B, it was left without being decomposed as it was, and the shape was maintained.

Further, since the resin which is not decomposed by microorganisms and the organic substance which can be decomposed by microorganisms are mixed by a simple mixing method such as stirring, the processing method is restricted, and the product that can be molded is simple such as a washbasin. Was limited to big products. That is, the biodegradable plastic obtained by the conventional method cannot be applied to near net shape processing such as injection molding method from the viewpoint of fluidity and has a drawback that a small product having a complicated shape cannot be produced.

Therefore, the present invention has been devised in order to effectively solve these problems, and its purpose is to effectively decompose microorganisms and to produce small products having a complicated shape. It provides a biodegradable plastic that can be made.

[0007]

In order to achieve the above-mentioned object, the first invention is that the surface of mother particles made of non-degradable microorganisms that are not decomposed by microorganisms is decomposed by microorganisms such as natural polymers. A microcapsule powder obtained by adhering child particles made of a biodegradable polymer into a microcapsule, collecting the microcapsule powder, and molding the microcapsule powder into a predetermined shape by hot pressing or the like. Is on the surface of mother particles made of biodegradable polymer that is decomposed by microorganisms such as natural polymer,
The microcapsule powder is formed by adhering child particles made of a thermoplastic polymer that is not decomposed by microorganisms into microcapsule powder, and the microcapsule powder is collected and molded into a predetermined shape by hot pressing or the like.

[0008]

The present invention is constructed as described above,
In the first invention, the microbial non-degradable polymer which is not decomposed by the microorganism and the microbial degradable polymer which is decomposed by the microorganism are uniformly dispersed, so that the microbial degradable polymers which are decomposed by the microorganism are connected to each other. Good transfer of microorganisms and improved surface quality and strength. Further, since the non-biodegradable polymers that are not decomposed by the microorganisms do not harden, the biodegradable polymers are decomposed and the non-biodegradable polymers are separated. Further, in the second invention, contrary to the first invention, the surface of the mother particles composed of the microbial degradable polymer, microparticles are formed by attaching child particles composed of a thermoplastic polymer which is not decomposed by microorganisms. Therefore, even if the shape of the mother particles is uneven or needle-like, the shape of the entire microcapsule powder is formed into a substantially spherical shape by the child particles attached to the periphery thereof. In addition, since the child particles are thermoplastic, the fluidity can be improved by heating to enable injection molding, and small products with complex shapes can be made. Product quality is also improved.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is an enlarged schematic view of the microbial degradable plastic according to the first invention. As shown in the figure, this microbial-degradable plastic consists of a microbial-degradable polymer that is decomposed by a microorganism such as a natural polymer on the surface of a mother particle 1 that is a microbial-non-degradable polymer that is not degraded by underground microorganisms. The child particles 2 are adhered to form microcapsule microcapsule powder 3, and the microcapsule powder 3 is collected and molded into a predetermined shape by hot pressing or the like.

The mother particles 1 are spherical particles having a particle size of about several tens of μ and are produced, for example, by finely crushing a synthetic polymer excluding a part of vinyl polymer, polyethylene, and fatty acid polyester with a crusher or the like. Will be done.

On the other hand, the child particles 2 are made of, for example, a natural polymer such as starch, gelatin, or cellulose, or a fatty acid polyester material having a structure similar to or substantially the same as these natural polymers. Further, the child particles 2 are spherical particles having a particle size of about several μ, and like the mother particles 1, the natural polymer described above is finely crushed by a crusher or the like to be manufactured. Then, the micro-capsule powder 3 is manufactured by attaching the child particles 2 to the surface of the mother particles 1 by electrostatic adhesion, mechanochemical method or the like.

In the microbial disintegrating plastic molded as described above, a microbial degradable polymer that is decomposed by microorganisms is attached to the surface of a microbial non-degradable polymer that is not decomposed by microorganisms in the ground to form one solid. Since the microcapsule powders 3 having two kinds of functions are gathered and molded into a predetermined shape by hot pressing or the like, it becomes difficult to form a space at the boundary between them and it becomes difficult to form a space. The mixing will be uniform. Therefore, the microbial degradable polymers that are decomposed by microorganisms are connected in series, while the microbial non-degradable polymers that are not decomposed by microorganisms are in an independent state. As a result of the good transmission of the microorganisms, the decomposition by the microorganisms is also favorably carried out, the molded articles tend to fall apart, the volume is reduced, and the surface quality and strength are also improved.

Next, a modified embodiment of the present invention will be described.

FIG. 2 is a molding resin in which a non-decomposable polymer 1a which is not decomposed by microorganisms such as vinyl polymers and polyethylene and light (ultraviolet rays) and a photodegradable polymer 1b which is decomposed when exposed to light are mixed. FIG. 3 is an enlarged schematic view showing the composition, and FIG. 3 is a capsule made of capsule powder in which microparticles made of the photodegradable polymer 1b are adhered to the surface of mother particles made of the nondegradable polymer 1b to form microcapsules. It is an enlarged schematic diagram which shows powder decomposable plastic. That is, the molding resin composition shown in FIG. 2 and the photodegradable plastic shown in FIG. 3 use a photodegradable polymer that decomposes when exposed to light (ultraviolet rays) instead of the above-mentioned microbial degradable polymer. The object is to decompose the molded article by light (ultraviolet rays) instead of microorganisms.

As shown in FIG. 2, in the molding resin composition in which the non-decomposable polymer 1a and the photo-decomposable polymer 1b are simply mixed, the mixture becomes non-uniform, resulting in non-decomposition. Since the degradable polymer 1a is bound to each other, even if the photodegradable polymer 1a is decomposed, the non-degradable polymer 1a
The a is not decomposed and maintains its shape. On the other hand, in the photodegradable plastic shown in FIG. 3, since the nondegradable polymer is in an independent state as in the first embodiment, it collapses when the surrounding photodegradable polymer 1b is decomposed. As a result, they will move from that position and tend to fall apart. Therefore, the photodegradable plastic shown in FIG. 3 is decomposed by light (ultraviolet rays) as compared with the molding resin composition obtained by simply mixing the non-degradable polymer 1a and the photodegradable polymer 1b shown in FIG. Will be done well.

As described above, according to the present invention, the non-decomposable polymer which is not decomposed by microorganisms or light (ultraviolet rays) and the degradable polymer which is decomposed by microorganisms or light (ultraviolet rays) are molded by the microcapsule capsule powder 3. By doing so, it is possible to favorably disassemble the molded product, which can contribute to solving problems such as shortage of landfill. It is needless to say that the microbial-disintegrating plastic of the present invention can be applied to a functionally gradient material.

Next, an embodiment of the second invention will be described.

As shown in FIG. 5, in the present invention, contrary to the above-mentioned first invention, the microbial degradable polymer is used as the mother particle 4, and the mother particle 4 is surrounded by child particles made of the thermoplastic polymer. The microcapsule powder 6 to which 5 is attached is used. As a result, in the present invention, kneading is possible, injection molding can be used, and small products having complicated shapes such as buttons and rings can be obtained. That is, according to the present invention, as shown in FIG. 6, even if the shape of the microbial-degradable polymer to be the mother particles 4 is irregular or needle-shaped, the microparticles 6 attached to the periphery of the microcapsule powder 6 Since the whole is modified into a substantially spherical shape, the particle shape of the mother particle 4,
Particle size and particle size distribution are not restricted. Therefore, handling properties, kneading properties and mixing properties are improved, and uniform and good products can be obtained at low cost. In addition, due to the uniform mixing, the microbe-degradable polymer is connected from the surface of the product to the inside in a micro-net shape, and the microbes that have entered from the surface of the molded product do not remain and the overall biodegradability is high. Molecules can be broken down. In addition, like this,
By encapsulating a mother particle 4 made of a microbial degradable polymer with child particles 5 made of a thermoplastic polymer,
When the microorganisms are not transmitted to the mother particles 4, as shown in FIG. 7, if the child particles 5a made of a biodegradable polymer are used as a part of the child particles 5, this serves as a means for transmitting the microorganisms to the adjacent mother particles 4. , Decomposition is performed well.

Further, as another embodiment, as shown in FIG. 8, a thermosetting polymer having a relatively high strength is used for the child particles 5b, and the child particles 5b made of the thermosetting polymer are used around the child particles 5b. By using the composite microcapsule powder 8 formed by adhering the grandchild particles 7 made of a thermoplastic polymer, it is possible to obtain a small product having a complicated shape with strength.
Also in this case, of course, as in FIG. 7, a biodegradable polymer may be used for part of the child particles 5b and the grandchild particles 7.

[0021]

In summary, according to the present invention, molded articles can be decomposed satisfactorily, which can contribute to the elimination of environmental problems such as landfill shortages, and the efficiency of transporting plastic waste can be improved. It has excellent effects such as reduction of processing cost.

[Brief description of drawings]

FIG. 1 is an enlarged schematic view showing an embodiment of the first invention.

FIG. 2 is an enlarged schematic view showing another modified embodiment of the first invention.

FIG. 3 is an enlarged schematic view showing another modified embodiment of the first invention.

FIG. 4 is an enlarged schematic view showing a conventional biodegradable plastic.

FIG. 5 is an enlarged schematic view showing an example of the microcapsule powder used in the second invention.

FIG. 6 is an enlarged schematic view showing an example of the microcapsule powder used in the second invention.

FIG. 7 is an enlarged schematic view showing another embodiment of the microcapsule powder used in the second invention.

FIG. 8 is an enlarged schematic view showing an example of the composite microcapsule powder used in the second invention.

[Explanation of symbols]

 1,4 Mother particles 2,5 Child particles 3,6 Microcapsule powder

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Claims (2)

[Claims] 1. Microparticles are formed by attaching, to the surface of mother particles made of non-degradable microorganisms that are not decomposed by microorganisms, child particles made of microorganisms that are decomposed by microorganisms such as natural polymers. A microbial-disintegrating plastic, characterized in that microcapsule powder is formed, the microcapsule powder is collected, and molded into a predetermined shape by hot pressing or the like. 2. Microcapsules in which microparticles made of a thermoplastic polymer that is not decomposed by microorganisms are adhered to the surface of mother particles made of a biodegradable polymer that is decomposed by microorganisms such as natural polymers. A microbial-disintegrating plastic, characterized in that a powder is formed, the microcapsule powder is aggregated, and molded into a predetermined shape by hot pressing or the like.