JP2003335966A - Plastic material imparted with biodegradability - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plastic material having a combination of long-term reliability with biodegradability, and to provide a molded product comprising the plastic material. <P>SOLUTION: The plastic material is obtained by incorporating a plastic degradation promoting factor in a non-biodegradable plastic material. The plastic molded product is obtained by molding the plastic material. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a plastic material obtained by imparting biodegradability to a non-biodegradable plastic, a molded article containing the plastic material, and a method for producing the same.

[0002]

2. Description of the Related Art Plastics have now spread to all fields of life and industry, and the annual production of plastics has reached 100 million tons. Most of them are discarded after use, which has been recognized as one of the causes of disturbing the global environment. Currently, the most noticeable solutions are plastic recycling and the use of biodegradable polymers. Regarding plastic recycling, the Home Appliance Recycling Law is 2 to recycle used electrical products.
Although it started in April 001, it has not collected and recycled waste products except four large electric appliances such as TV, refrigerator, cooler and washing machine.
There are no legal restrictions. Therefore, most electric products are thrown away as non-combustible waste at the time of disposal. Even if the shape is small, if a large number of units are sold, a large amount of waste is generated as a whole. This is a serious problem nowadays due to the lack of waste disposal sites. Further, as a method of treating wastes which is frequently performed at present, there is a method of shreddering the wastes. However, this shredder treatment only reduces the volume of waste, and if it is landfilled, the waste remains as it is for decades or hundreds of years, and is not a basic solution. Even if the shredder dust is material-recycled, since all parts are finely crushed, for example, valuable materials such as copper are also mixed with other low-value materials, resulting in decreased purity and recovery. There are problems such as deterioration of efficiency.

On the other hand, the use of biodegradable polymers is as follows.
It is considered that there are two advantages as follows. The first point is that the casing and the structure portion that occupy most of the volume of the electric product are made of biodegradable materials, and these portions and non-biodegradable portions such as electronic parts or substrates are If it is a structure that can be easily divided, such as a stopper or a fitting structure,
With a simple dismantling process, the part to be recycled and the biodegradable part that can be discarded as it is can be processed separately, so it is expected that recovery efficiency will increase. The second point is, for example, that the outermost surface of the casing of a radio, a microphone, a neck TV, a keyboard, a walkman, a mobile phone, a radio-cassette, an earphone, etc. is made of a naturally disintegrating resin centering on a biodegradable material. . By making the parts that frequently come into contact with the human body with natural degradable resins centered on biodegradable materials, it is more safe for the human body and the environment than ordinary synthetic resins. Electrical appliances can be provided.

However, while biodegradable polymers are highly likely to provide materials that are highly compatible with the environment,
The problem is that the cost is high, and many of them are inferior to the current general-purpose plastics in terms of performance. For example, an aliphatic polyester resin, which is a typical example of a biodegradable polymer, generally has a low melting point and has insufficient physical properties (particularly heat resistance and impact resistance) suitable for practical molded articles. Therefore, various studies such as addition of inorganic filler, improvement of crystallization rate by addition of crystal nucleating agent, blending with biodegradable resin exhibiting rubber-like property with low glass transition point, etc. have been conducted. Several patent applications have already been filed regarding molded articles using such plastics (Japanese Patent Laid-Open Nos. 3-290461 and 4-1469).
52, JP-A-4-325526, etc.).

When the biodegradable polymer is applied to housings of electric products, electronic devices, etc., heat resistance and long-term reliability (durability under constant temperature and humidity conditions) are required. Electric products and electronic devices have a variety of product lives, but it is necessary for small audio products to maintain their physical properties for 3 to 7 years under the conditions of 30 ° C. and 80% relative humidity. However, in the above-mentioned previously known inventions, it is the current situation that long-term reliability has not been sufficiently ensured. Therefore, at the present time, biodegradable polymers are mainly used for aliphatic polyester resins, materials for agriculture, forestry and fisheries (films, planting pots, fishing lines, fishnets, etc.),
It is only used for applications that do not require long-term reliability, such as civil engineering materials (water retaining sheets, plant nets, sandbags, etc.), packaging / container fields (things such as soil and food that are difficult to recycle) .

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to impart biodegradability to a plastic that can secure long-term reliability but does not have biodegradability, and reduce the environmental load at the time of disposal. It is the one to try. That is, the present invention is
It is an object to provide a plastic material having both long-term reliability and biodegradability, a molded article containing the plastic material, and a method for producing the same.

[0007]

Means for Solving the Problems As a result of intensive studies on the biodegradability of a plastic material used as a casing material for electric appliances or electronic devices, the present inventors have found that
It has been found that biodegradability can be imparted to a general-purpose plastic material by including a factor that promotes decomposition in the plastic material. More specifically, for a plastic material that can secure long-term reliability but does not have biodegradability, by intentionally including a factor that promotes biodegradability such as bacteria, biodegradation of the plastic material is possible. Properties to reduce the environmental load when disposing after use.

That is, the present invention provides (1) a plastic material containing a biodegradable plastic and a plastic degradation promoting factor, (2)
The plastic material according to (1) above, wherein the plastic decomposition promoting factor is a bacterium.
(3) The plastic decomposition promoting factor is a bacterial assimilation substance, and contains the plastic material according to (1) above, (4) a non-biodegradable plastic, and a plastic decomposition promoting factor. (5) The molded product according to (4) above, which is a housing of an electric product or an electronic device.

The present invention also provides (6) the use of a plastic decomposition accelerating factor for the decomposition of a plastic having no biodegradability, (7) a plastic having no biodegradability before being melted A method for producing a plastic molded product, which comprises molding after adding or mixing a plastic decomposition accelerating factor at time or after melting, (8) wherein the plastic decomposition accelerating factor is a bacterium (7) A method for producing a plastic molded article according to
(9) The method for producing a plastic molded article according to (7) above, wherein the plastic decomposition accelerating factor is a bacterial assimilation substance, and (10) molding is performed by film molding, extrusion molding or injection molding. The method for producing a plastic molded article according to (7) above.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The non-biodegradable plastic used in the present invention is a plastic which does not decompose into low molecular weight compounds and finally water and carbon dioxide by the involvement of microorganisms in the natural world even after use. Commonly recognized plastics are mentioned. Above all, a plastic having long-term reliability, which is less susceptible to quality deterioration due to aging, is preferable. Furthermore, a plastic having excellent impact resistance and heat resistance is more preferable. Examples of such plastics include polystyrene, which is often used as a housing for electric appliances or electronic devices, acrylonitrile-butadiene-styrene (ABS), polycarbonate, acrylic resin, polyester represented by polyethylene terephthalate (PET), and the like. Examples thereof include epoxy resin, melamine resin, urea resin, acrylic resin, phenol resin, polyimide resin, polyamide resin, polyester resin, Teflon (registered trademark) resin, nylon resin, and cellulose resin.

The plastic decomposition promoting factor used in the present invention is not particularly limited as long as it promotes the decomposition of the above-mentioned non-biodegradable plastic. As the plastic decomposition promoting factor, bacteria (fungi) are firstly mentioned. The type of the bacterium is not particularly limited as long as it can accelerate the degradation of the plastic having no biodegradability. Among them, (a) low toxicity to human body and ecosystem, preferably harmless, (b)
Being able to assimilate the above non-biodegradable plastics, (c) be able to take a dormant state by forming spores according to the environmental conditions surrounding bacteria, and (d) be able to survive even in a high temperature environment. Bacteria having at least one or more properties capable of producing are preferred.
Of these, bacteria having at least the property (a), such as Bacillus natto and lactic acid bacteria, are more preferable. Further, a bacterium having at least the two properties of (a) and (b) or a bacterium having at least the two properties of (a) and {(c) or (d)} is preferable. In particular, bacteria having three properties (a), (b), and {(c) or (d)} are preferable.

Bacteria capable of assimilating the above non-biodegradable plastics are not particularly limited, but include, for example, Flavobacterium bacteria, Shademonas species, Aciinobacter species, Methanocaucus species, and Microkerchaus species. , Bacterium species, mycobacterial species, achromobacter species, and erythomoonas species. These bacteria may be used alone or in combination of two or more. In addition, the bacterium as described above is not limited to the bacterium described as the above specific example, and can be easily obtained by a known method. For example, a non-biodegradable plastic contained in the plastic material of the present invention is made into a fine powder, thinly applied to the surface layer of an agar medium, and the manner in which the plastic is decomposed is observed. A microorganism that assimilates the plastic can be isolated by a known method such as repeating subculture. Further, as a method for obtaining bacteria capable of assimilating plastics having no biodegradability, Japanese Patent Laid-Open No. 10-24
The method described in 8595 or the like may be used.

Examples of the spore-forming bacteria include aerobic bacteria of the genus Bacillus and anaerobic bacteria of the genus Clostridium. The bacteria are spores when they are exposed to physical or chemical stimuli such as heat, chemical treatment such as disinfectant, ultraviolet rays and irradiation, or when carbon and nitrogen sources are deficient and nutritional conditions are not established. Form almost all of its metabolism, such as respiration, and almost completely stop its biological activity. Then, when the environment changes to a condition advantageous for the growth of the bacterium, the germination starts again and the growth starts. Utilizing such a property has an advantage that the killing of the bacteria, which is a plastic decomposition accelerating factor, can be reduced when the bacteria are mixed with the non-biodegradable plastic. That is, when other components are mixed with the plastic, the plastic is melted, and at that time, the temperature becomes relatively high, which may kill bacteria. However, the spore-forming bacterium can form spores in a high-temperature environment and can withstand heat, and thus killing of bacteria can be avoided as much as possible. Furthermore, when using a molded article using the plastic material according to the present invention, the bacteria are put into a dormant state such as forming spores, and germinated by subjecting them to a known treatment at the time of disposal, or in the soil at the time of disposal, Place the molded product in an atmosphere in which bacteria are activated in river water, seawater, or in compost to accelerate the decomposition of the non-biodegradable plastic by bacteria only after discarding the molded product. You can also

Bacteria that can survive in a high temperature environment include microorganisms called thermophiles.
When a bacterium having such a property is used, when the bacterium which is a plastic decomposition accelerating factor is mixed with the non-biodegradable plastic for the same reason as described in the spore-forming bacterium, the bacterium of There is an advantage that death can be reduced. The thermophilic bacterium is roughly classified into an extremely thermophilic bacterium that can survive even in an environment of 75 ° C. or higher and a medium thermophilic bacterium that can survive in an environment of 55 ° C. to 75 ° C. In the present invention, May be used, but it is preferable to use an extreme thermophile. The thermophile may be a facultative thermophile that can survive at 37 ° C or lower, or an obligate thermophile that cannot survive at 37 ° C or lower, but the facultative thermophile is preferable. .

Secondly, examples of the plastic decomposition promoting factor used in the present invention include bacterial assimilation substances. The bacterium-utilizing substance is not particularly limited as long as the bacterium can assimilate. Specific examples include carbohydrates (sugars), fats (fatty acids), proteins (amino acids), and the like. The bacterium-assimilating substance is preferably in a form in which bacteria can be efficiently ingested, and it is possible to combine a plurality of types. Examples of the bacteria referred to herein include bacteria that grow in the environment in which the molded product using the plastic material according to the present invention is placed at the time of disposal. Further, the bacterium referred to herein may be the bacterium described above as a plastic decomposition promoting factor contained in the plastic material of the present invention. That is, as the plastic decomposition accelerating factor used in the present invention, the above-mentioned bacteria and a substance which can be assimilated by the bacteria may be combined.

In the plastic material according to the present invention, in addition to the above-mentioned factors for promoting plastic decomposition, a reinforcing material, an inorganic filler, an antioxidant, a heat stabilizer, an ultraviolet absorber, a lubricant, a wax, a coloring agent or Additives such as a crystallization accelerator may be contained. As the reinforcing material,
Examples thereof include glass microbeads, carbon fibers, chalk, quartz such as novoculite, asbestos, feldspar, mica, talc, silicates such as wollastonite, kaolin and the like. The reinforcing material is 1
The seeds may be used alone or in combination of two or more. Examples of the inorganic filler include carbon or silicon dioxide, fine particles of metal oxides such as alumina, silica, magnesia or ferrite; silicates such as talc, mica, kaolin or zeolite; barium sulfate, calcium carbonate or fullerene. And the like. Of these, silicates, carbon or silicon dioxide are preferable. The said inorganic filler may be used individually by 1 type, and may be used in mixture of 2 or more type. The function of the inorganic filler is not particularly limited, but it may be used as the above-mentioned reinforcing material. Moreover, silicates as inorganic fillers function as flame retardants. As silicates suitable as such an inorganic filler, silicates having a silicon dioxide content of about 50% or more are more preferable. This is because substances other than silicates (eg MgO, CaO,
This is because Fe ₂ O ₃ , Al ₂ O _3, etc.) is contained to some extent. However, it is preferable that the effect as an inorganic filler for flame retardancy is not hindered by impurities. Further, the content of the inorganic filler may be appropriately selected according to its type, and cannot be generally stated. For example, when the inorganic filler is a silicate, its content is preferably about 5 to 30% by weight based on the whole biodegradable plastic material according to the present invention.

Examples of the antioxidants include phenol-based, amine-based, phosphorus-based, sulfur-based, hydroquinone-based,
Alternatively, quinoline-based antioxidants and the like can be mentioned. Examples of the phenolic antioxidant include hindered phenols such as 2,6-di-t-butyl-p-cresol, 1,3,5-trimethyl-2,4,6-tris (3,5- Di-t-butyl-4-hydroxybenzyl)
Benzene, 2,2'-methylenebis (4-methyl-6-
t-butylphenol), 4,4'-methylenebis (2,6-di-t-butylphenol), 4,4'-butylidenebis (3-methyl-6-t-butylphenol), 1,6-hexanediol-bis [ 3- (3,5
-Di-t-butyl-4-hydroxyphenyl) propionate] and the like C _2-10 alkylenediol-bis [3-
(3,5-di-branched C _3-6 alkyl-4-hydroxyphenyl) propionate]; eg triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-)
Hydroxyphenyl) propionate] or the like di- or trioxy C _2-4 alkylenediol-bis [3- (3,3
5-di-branched C _3-6 alkyl-4-hydroxyphenyl) propionate]; for example glycerin tris [3-
(3,5-di-t-butyl-4-hydroxyphenyl)
C _3-8 alkanetriol-bis [3- (3,5-di-branched C _3-6 alkyl-4-hydroxyphenyl) propionate] such as propionate]; for example pentaerythritol tetrakis [3- (3,5-di -T-butyl-
4-hydroxyphenyl) propionate] and the like C _4-8
Alkanetetraol tetrakis [3- (3,5-di-
Branched C _3-6 alkyl-4-hydroxyphenyl) propionate]; for example, n-octadecyl-3- (4 ′,
5'-di-t-butylphenol) propionate, n
-Octadecyl-3- (4'-hydroxy-3 ', 5'
-Di-t-butylphenol) propionate, stearyl-2- (3,5-di-t-butyl-4-hydroxyphenol) propionate, distearyl-3,5-
Di-t-butyl-4-hydroxybenzylphosphonate, 2-t-butyl-6- (3-t-butyl-5-methyl-2-hydroxybenzyl) -4-methylphenyl acrylate, N, N'-hexamethylene Screw (3,5-
Di-t-butyl-4-hydroxy-hydrocinnamide), 3,9-bis {2- [3- (3-t-butyl-4)
-Hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl} -2,4,8,10-
Tetraoxaspiro [5,5] undecane, 4,4'-
Thiobis (3-methyl-6-t-butylphenol),
Alternatively, 1,1,3-tris (2-methyl-4-hydroxy-5-t-butylphenol) butane and the like can be mentioned.

Examples of the amine-based antioxidant include phenyl-1-naphthylamine, phenyl-2-naphthylamine, N, N'-diphenyl-1,4-phenylenediamine, or N-phenyl-N'-cyclohexyl-. 1,4-phenylenediamine and the like can be mentioned.

Examples of the phosphorus-based antioxidant include:
Triisodecylphosphite, triphenylphosphite, trisnonylphenylphosphite, diphenylisodecylphosphite, phenyldiisodecylphosphite, 2,2-methylenebis (4,6-di-t-butylphenyl) octylphosphite, 4 , 4'-butylidene bis (3-methyl-6-t-butylphenyl) ditridecyl phosphite, tris (2,4-di-t-butylphenyl) phosphite, tris (2-t-butyl-4)
-Methylphenyl) phosphite, tris (2,4-di-t-amylphenyl) phosphite, tris (2-t
-Butylphenyl) phosphite, bis (2-t-butylphenyl) phenylphosphite, tris [2-
(1,1-Dimethylpropyl) -phenyl] phosphite, tris [2,4- (1,1-dimethylpropyl)-
Phenyl] phosphite, tris (2-cyclohexylphenyl) phosphite, tris (2-t-butyl-4)
-Phenylphenyl) phosphite and other phosphite compounds; triethylphosphine, tripropylphosphine, tributylphosphine, tricyclohexylphosphine, diphenylvinylphosphine, allyldiphenylphosphine, triphenylphosphine, methylphenyl-p-anisylphosphine, p-anis Sildiphenylphosphine, p-tolyldiphenylphosphine, di-p-
Anisylphenylphosphine, di-p-tolylphenylphosphine, tri-m-aminophenylphosphine, tri-2,4-dimethylphenylphosphine, tri-2,
4,6-trimethylphenylphosphine, tri-o-tolylphosphine, tri-m-tolylphosphine, tri-
Examples thereof include phosphine compounds such as p-tolylphosphine, tri-o-anisylphosphine, tri-p-anisylphosphine, and 1,4-bis (diphenylphosphino) butane.

Examples of the hydroquinone type antioxidant include
Examples include 2,5-di-t-butylhydroquinone and the like, and examples of the quinoline-based antioxidant include 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline and the like, Examples of the sulfur-based antioxidant include dilauryl thiodipropionate and distearyl thiodipropionate. Among them, preferred antioxidants include phenolic antioxidants (particularly, hindered phenols), and more preferably polyol-poly [(branched C _3-6 alkyl group and hydroxy group-substituted phenyl) propionate]. Etc. The antioxidants may be used alone or in combination of two or more.

Examples of the heat stabilizer include nitrogen-containing compounds (basic nitrogen-containing compounds such as polyamide, poly-β-alanine copolymer, polyacrylamide, polyurethane, melamine, cyanoguanidine, and melamine-formaldehyde condensate). , Alkali or alkaline earth metal-containing compounds [in particular, organic carboxylic acid metal salts (calcium stearate, 12-hydroxy calcium stearate, etc.), metal oxides (magnesium oxide, calcium oxide, aluminum oxide, etc.), metal hydroxides (water Magnesium oxide, calcium hydroxide, aluminum hydroxide, etc.), metal carbonates, etc.], zeolite, hydrotalcite, etc. In particular, an alkali or alkaline earth metal-containing compound (particularly an alkaline earth metal-containing compound such as a magnesium compound or a calcium compound), zeolite, or hydrotalcite is preferable. The heat stabilizers may be used alone or in combination of two or more.

Examples of the ultraviolet absorber include conventionally known benzophenone-based, benzotriazole-based, cyanoacrylate-based, salicylate-based, oxalic acid anilide-based and the like. For example, [2-hydroxy-4- (methacryloyloxyethoxy) benzophenone] -methyl methacrylate copolymer, [2-hydroxy-4- (methacryloyloxymethoxy) benzophenone] -methyl methacrylate copolymer, [2-hydroxy -4- (methacryloyloxyoctoxy) benzophenone] -methyl methacrylate copolymer, [2-hydroxy-4- (methacryloyloxidedecyloxy) benzophenone]-
Methyl methacrylate copolymer, [2-hydroxy-4-
(Methacryloyloxybenzyloxy) benzophenone] -methyl methacrylate copolymer, [2,2′-dihydroxy-4- (methacryloyloxyethoxy) benzophenone] -methyl methacrylate copolymer, [2,2
2'-dihydroxy-4- (methacryloyloxymethoxy) benzophenone] -methyl methacrylate copolymer, [2,2'-dihydroxy-4- (methacryloyloxyoctoxybenzophenone) -methyl methacrylate copolymer and the like can be mentioned. To be The ultraviolet absorbers may be used alone or in combination of two or more.

Examples of the lubricant include petroleum-based lubricating oils such as liquid paraffin; synthetic lubricating oils such as halogenated hydrocarbons, diester oils, silicone oils and fluorosilicones; various modified silicone oils (epoxy modified, amino modified, alkyl). Modified, polyether modified, etc.); silicon-based lubricating substances such as copolymers of organic compounds such as polyoxyalkylene glycol and silicon; silicone copolymers; various fluorosurfactants such as fluoroalkyl compounds; trifluoro Fluorine-based lubricating substances such as low-polymerized methylene chloride; higher aliphatic alcohols; higher aliphatic amides; higher fatty acid esters; higher fatty acid salts; or molybdenum disulfide. Among these, a silicon copolymer is particularly preferable. The silicone copolymer, acrylic resin, polystyrene resin, polynitrile resin, polyamide resin, polyolefin resin, epoxy resin, polybutyral resin, melamine resin, vinyl chloride resin,
A resin obtained by block- or graft-polymerizing silicone with a resin such as a polyurethane resin or a polyvinyl ether resin is more preferable. These lubricating substances may be used alone or in combination of two or more.

Examples of the above waxes include olefin wax such as polypropylene wax or polyethylene wax, paraffin wax, Fischer-Tropsch wax, microcrystalline wax, montan wax, fatty acid amide wax, higher aliphatic alcohol wax, and higher wax. Fatty acid wax,
Examples thereof include fatty acid ester wax, carnauba wax, rice wax and the like. The function of the wax is not particularly limited, but it may be used as the above-mentioned lubricant. These waxes may be used alone or in combination of two or more.

Examples of the colorant include inorganic pigments, organic pigments and dyes. Examples of the inorganic pigment include chrome pigments, cadmium pigments, iron pigments, cobalt pigments, ultramarine blue, and dark blue. Specific examples of organic pigments and dyes include carbon black; phthalocyanine pigments such as phthalocyanine copper; quinacridone pigments such as quinacridone magenta and quinacridone red; hansa yellow, for example.
Examples thereof include azo pigments such as disazo yellow, permanent yellow, permanent red, and naphthol red; for example, spirit black SB, nigrosine base, nigrosine dye such as oil black BW, oil blue, and alkali blue. The colorants may be used alone or in combination of two or more.

Examples of the crystallization accelerator include p-
sodium t-butylbenzoate, sodium montanate, calcium montanate, sodium palmitate,
Organic acid salts such as calcium stearate; inorganic salts such as calcium carbonate, calcium silicate, magnesium silicate, calcium sulfate, barium sulfate, and talc; metal oxides such as zinc oxide, magnesium oxide, and titanium oxide. These crystallization accelerators may be used alone or in combination of two or more.

Further, the plastic material according to the present invention may contain a biodegradable resin. By including the biodegradable resin, the biodegradability of the plastic material according to the present invention can be improved. However, the content of the biodegradable resin is preferably within a range that does not impair the long-term reliability of the plastic material according to the present invention. Specifically, it is about 50% by weight or less of the plastic component of the plastic material according to the present invention. Preferably there is.

As the above-mentioned biodegradable resin, after use, a low molecular weight compound is involved in microorganisms in the natural world, and finally decomposed into water and carbon dioxide (Biodegradable Plastics Research Group, ISO / TC-207 / If it is SC3), there is no particular limitation. Specifically, it has biodegradability, for example, any one of polysaccharides, peptides, aliphatic polyesters, polyamino acids, polyvinyl alcohols, polyamides, polyalkylene glycols, etc., or at least one of the above compounds. Examples thereof include copolymers. Among them, the aliphatic polyester is preferable as the biodegradable resin used in the present invention because it has excellent mixing properties and mass productivity.

Specifically, the aliphatic polyester is preferably polylactic acid such as poly-L-lactic acid (PLLA), a random copolymer of L-lactic acid and D-lactic acid, or a derivative thereof. Of course, classified into other polyesters, for example, polycaprolactone, polyhydroxybutyric acid, polyhydroxyvaleric acid, polyethylene succinate, polybutylene succinate, polybutylene adipate, polymalic acid, polyglycolic acid, polysuccinic acid ester, polyoxalic acid ester. , Butyrene polydiglycolate, polydioxanone, microbial synthetic polyester, etc. can also be used. Here, as the microbial synthetic polyester, 3-hydroxybutyrate (3HB), 3-
Examples thereof include hydroxyvalerate (3HV) and copolymers thereof. As the above-mentioned polysaccharide, cellulose,
Mention may be made of starch, chitosan, dextran or any of their derivatives or copolymers containing one of them. As the peptide, collagen,
Examples include casein, fibrin, gelatin and the like. Examples of the polyamide include nylon 4 and nylon 2 /
Examples thereof include nylon 6 copolymer.

The plastic material according to the present invention can be obtained by mixing a non-biodegradable plastic, a plastic decomposition accelerating factor and, if desired, the above-mentioned other components. The mixing method is not particularly limited, but a polymer component such as a plastic having no biodegradability and, if desired, another plastic or resin (in this section, referred to as “plastic component”) is melted,
There may be mentioned a method in which a component other than that including a plastic culture promoting factor (referred to as "non-plastic component" in this section) is added to the melt. After the addition, stirring may be performed by a known method. The order of addition is not particularly limited, and two or more kinds of non-plastic components may be added at the same time, or may be added one by one. Further, a non-plastic component may be added before or at the time of melting the above-mentioned plastic component. Further, a part of the non-plastic component may be added before or during melting of the plastic component, and the rest of the non-plastic component may be added after melting of the plastic. That is, if the non-plastic component is contained in the plastic component, the timing of addition is not limited.

By molding the plastic material according to the present invention obtained as described above, the plastic molded article according to the present invention can be obtained. The plastic molded product is not particularly limited and may have various shapes and structures. Specifically, the molded product according to the present invention is preferably, for example, a radio, a microphone, a TV, a keyboard, a portable music player, a personal computer, or other electrical product or a housing of an electronic device.

As a method for molding the plastic material according to the present invention when the molded article according to the present invention is manufactured, known means may be used and can be appropriately selected depending on the type of the molded article. As a concrete molding method, for example,
Film molding, extrusion molding, injection molding, etc. can be mentioned,
Of these, injection molding is particularly preferable. More specifically, extrusion molding can be performed using an extrusion molding machine such as a single-screw extruder, a multi-screw extruder, a tandem extruder, and the injection molding,
For example, it can be performed with an injection molding machine such as an in-line screw type injection molding machine, a multi-layer injection molding machine, or a double-headed injection molding machine. As a preferred method for producing the molded article according to the present invention, a plastic having no biodegradability and a plastic decomposition accelerating factor and, if desired, other components are added in an amount of about 20.
The mixture is mixed for about 2 minutes at about 500 rpm with an H. Henschel mixer of about L, and then melt-kneaded with a twin-screw extruder to obtain pellets, and the pellets are used to manufacture, for example, a casing of an electric appliance according to a conventional method. There is a method of doing.

The molded article according to the present invention is characterized by long-term reliability as well as biodegradability. As an index of the long-term reliability, the molded product according to the present invention shows a decrease in physical properties such as impact resistance of about 20 even when aged for 48 hours under constant temperature and constant humidity conditions of temperature 80 ° C. and relative humidity 80%. It is preferably within%.

[0034]

The plastic material of the present invention has biodegradability and long-term reliability. Therefore, by using the plastic material of the present invention, it is possible to impart biodegradability to a molded product that requires long-term reliability, such as a case of an electric product or an electronic device, and the environment at the time of discarding the molded product. The load is reduced. Furthermore, according to the present invention, after the storage stability period has elapsed, the biodegradability due to a decomposition accelerating factor such as bacteria is exerted so that the plastic material of the present invention can be used in a culture solution containing microorganisms or in soil. Decomposition can also proceed. As a result, the volume of waste can be reduced. Further, the plastic material of the present invention and a molded article containing the plastic material of the present invention,
Since the raw material is cheaper than biodegradable plastic and can be manufactured by a simple operation, it is extremely useful from the viewpoint of manufacturing cost.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Tsutomu Noguchi             6-735 Kita-Shinagawa, Shinagawa-ku, Tokyo Soni             -Inside the corporation (72) Inventor Yutaka Oki             6-735 Kita-Shinagawa, Shinagawa-ku, Tokyo Soni             -Inside the corporation F-term (reference) 4F071 AA08 AA12 AA22 AA31 AA34                       AA42 AA46 AA50 AA70 AA71                       AA75 AC02 AE22 AF52 BA01                       BB05 BB06 BC01 BC03 BC07                 4J002 AB011 AB042 AD002 BC031                       BG001 BN151 CC181 CD001                       CD031 CF001 CF061 CG001                       CK011 CL001 CN041 EF006                       EF056 FD202 FD206                 4J200 AA04 AA05 AA08 AA13 BA02                       BA03 BA05 BA07 BA09 BA23                       BA28 BA32 BA34 BA38 EA11                       EA21

Claims (10)

[Claims] 1. A plastic material containing a non-biodegradable plastic and a plastic decomposition promoting factor. 2. The plastic material according to claim 1, wherein the plastic decomposition promoting factor is a bacterium. 3. The plastic material according to claim 1, wherein the plastic decomposition promoting factor is a bacterial assimilation substance. 4. A molded article containing a plastic material containing a biodegradable plastic and a plastic degradation promoting factor. 5. The molded product according to claim 4, which is a housing for an electric product or an electronic device. 6. Use of a plastic decomposition accelerating factor for the decomposition of non-biodegradable plastics. 7. A method for producing a plastic molded article, which comprises adding a plastic decomposition accelerating factor to a non-biodegradable plastic before, during or after melting, mixing and molding. 8. The method for producing a plastic molded article according to claim 7, wherein the plastic decomposition accelerating factor is a bacterium. 9. The method for producing a plastic molded product according to claim 7, wherein the plastic decomposition accelerating factor is a bacterial assimilation substance. 10. The method for producing a plastic molded product according to claim 7, wherein the molding is performed by film molding, extrusion molding or injection molding.