JP2003089751A - Polyester molded product for box - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the biodegradable plastic material, especially a biodegradable polyester material, having long term reliability, and to further provide a molded product derived from the biodegradable plastic material. SOLUTION: The biodegradable plastic material is obtained by treating a biodegradable plastic material with a compound which can react with an active hydrogen in this material. A biodegradable plastic molded product is obtained form the treated material.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a biodegradable plastic material having improved durability and a biodegradable plastic molded article using the same material.

[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 started in April 2001 in order to recycle used electric products. Except for four large electric products such as TV, refrigerator, cooler, and washing machine,
There is no collection or recycling of waste products and 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.

As a treatment method which is frequently used nowadays, there is a method of shreddering waste. However, this shredder treatment only reduces the volume of waste, and if 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 housing and structure that occupy most of the volume of electrical products are made of biodegradable material, and non-biodegradable parts such as electronic parts and boards are screwed or fitted. With a structure that can be easily divided, such as a disassembly process, it is possible to separately treat the part to be recycled and the part that can be discarded as it is, and it is expected that the recovery efficiency will be improved. As a second point, for example, the outermost surface of a casing such as a radio, a microphone, a neck TV, a keyboard, a walkman, a mobile phone, a radio-cassette, an earphone is made of a biodegradable material. As described above, by making the part that has a high chance of coming into contact with the human body with a biodegradable material, it is possible to provide an electric product having higher safety than synthetic resin.

However, the biodegradable polymer used for the above-mentioned applications is not limited to any kind, and its physical properties are required for its use as a casing or a structural material for electric products. The present inventors have found that, for example, it is necessary at least that the physical properties are not deteriorated even if they are kept for 48 hours in an atmosphere having a temperature of 80 ° C. and a humidity of 80%.

Biodegradable polymers are organic materials that are decomposed and assimilated by the action of the natural world and living bodies, and have been developed as ideal environment-friendly materials. Examples of such biodegradable polymers include polysaccharide derivatives such as cellulose, starch, dextran and chitin, such as peptides such as collagen, casein, fibrin and gelatin.
Examples thereof include polyamino acids, for example, polyvinyl alcohol, polyamides such as nylon 4 and nylon 2 / nylon 6 copolymers, and aliphatic polyesters.

An aliphatic polyester resin, which is a typical example of a biodegradable polymer, generally has a low melting point, has insufficient physical properties (particularly heat resistance and impact resistance) suitable for practical molded articles, Various studies have been carried out, such as addition, improvement of crystallization rate by addition of crystal nucleating agent, blending with biodegradable resin showing rubber-like properties with low glass transition point, and such plastics were used. Regarding the molded product, some patent applications have already been filed (Japanese Patent Laid-Open No. Hei 3).
-290461, JP-A-4-146952, JP-A-4-325526). These molded products are used as films and packaging materials, and durability is not particularly required.

On the other hand, in the application of the biodegradable aliphatic polyester resin to the housing of electric products, electronic equipment, etc., heat resistance as well as 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. Considering the environment in which electric products and electronic devices are used under various temperature and humidity conditions, the current biodegradable polyester has a problem in terms of long-term reliability as described above. , It could not be used for the housing of electronic devices. At present, biodegradable polymers are mainly used for aliphatic polyester resins, materials for agriculture, forestry and fisheries (films, planting pots, fishing lines, fishnets, etc.), civil engineering materials (water retaining sheets, plant nets, sandbags, etc.), packaging, It has begun to be used in the container field (things that soil, food, etc. adhere to and are difficult to recycle).

As described above, when the biodegradable polyester resin is used for electric appliances, housings of electronic devices, etc., the physical properties are first kept under constant temperature and constant humidity (for example, 80 ° C., relative humidity 80%) for at least 48 hours. The minimum requirement is that no decline occurs. Even with the current biodegradable polyester, such as polylactic acid, which has the highest heat resistance,
When an aging test at 0 ° C. and a relative humidity of 80% is performed for 48 hours, the molecular weight is reduced by 60% due to hydrolysis (see Comparative Example 1 below), and it is difficult to apply it to housing materials for home electric appliances. As a factor causing such deterioration of physical properties, that is, hydrolysis, for example, in the case of polyester, it is known that the carboxyl group at the end of the polymer chain catalytically hydrolyzes the ester bond in the molecular chain. In order to ensure long-term reliability, the inventors of the present invention catalytically hydrolyze the main chain of active hydrogen in functional groups having active hydrogen such as carboxyl groups and hydroxyl groups in biodegradable plastic during use of the product. By not decomposing, the physical properties (eg strength, hydrolysis resistance, heat resistance) are maintained, and hydrolysis after disposal,
We also started to create a plastic material that can be decomposed by microorganisms that are commonly found in nature.

[0011]

SUMMARY OF THE INVENTION An object of the present invention is to provide a biodegradable plastic material capable of ensuring long-term reliability, particularly a biodegradable polyester material, and a molded product derived therefrom.

[0012]

Means for Solving the Problems The inventors of the present invention have conducted diligent research to ensure long-term reliability of biodegradable polyester for use as a casing material for electric products, electronic devices, etc. Long-term reliability by adding a compound that can react with active hydrogen in reactive polyesters and reacting with active hydrogen to reduce the amount of active hydrogen, especially by reducing the amount of residual fatty acid in the composition It has been found that an improvement in Further, it has been found that not only the biodegradable polyester but also the biodegradable polymer having an amide group and / or an amide bond can be treated in the same manner as the biodegradable polyester to reduce the amount of active hydrogen.
Here, active hydrogen is a compound having a bond of hydrogen with oxygen, nitrogen, etc., which is more reactive than a bond of carbon and hydrogen, and for example, a carboxyl group: —COOH, a hydroxyl group: —
OH, amino group: -NH _2, or an amide bond: -NH
CO- and the like.

More specifically, a compound capable of reacting with active hydrogen, such as a carbodiimide compound or a polyisocyanate compound, is reacted with a biodegradable plastic material to control the amount of fatty acid, that is, the acid value to a predetermined amount or less. Thus, for example, after the aging test at 80 ° C., 80% for 48 hours, a housing material having long-term reliability that does not cause deterioration of physical properties can be prepared, and further studies have been conducted to complete the present invention.

That is, according to the present invention, [1] a biodegradable plastic material treated with a compound capable of reacting with active hydrogen in the biodegradable plastic, [2] the biodegradable plastic material is a biodegradable polyester material. The biodegradable plastic material according to [1] above, characterized in that [3]
The biodegradable plastic material is a copolymer of a biodegradable polyester and a biodegradable polymer having an amino group and / or an amide bond, or a biodegradable polyester and a biodegradable polymer having an amino group and / or an amide bond. The biodegradable plastic material according to [1] above, [4] the acid value of the biodegradable plastic material treated with a compound capable of reacting with active hydrogen is 0.5 or less. The biodegradable plastic material according to the above [1], [5] a temperature of 80 ° C.,
The acid value increase is 0.2 or less and the molecular weight decrease is 10% or less even after aging for 48 hours under a constant temperature and humidity condition of a relative humidity of 80%. [1] Biodegradable plastic material, [6] The active hydrogen is derived from one or more atomic groups selected from a carboxyl group, a hydroxyl group, an amino group and an amide bond in the biodegradable plastic material. [1] the biodegradable plastic material, [7] the compound capable of reacting with active hydrogen is a crosslinking agent having a carbodiimide group, [1] the biodegradable plastic material, 8] The biodegradable plastic material according to the above [7], wherein the crosslinking agent having a carbodiimide group is dicyclohexylcarbodiimide or diisopropylcarbodiimide, [9] The biodegradable plastic material according to the above [1], which contains silicates, [10] The content of the silicates is 5 to 30% by weight based on the whole biodegradable plastic material. The biodegradable plastic material according to [9] above,
[11] A biodegradable plastic molded product obtained by molding a biodegradable plastic material treated with a compound capable of reacting with active hydrogen in the biodegradable plastic, [12] the biodegradable plastic material is a biodegradable polyester material. [13] The biodegradable plastic molded product according to [11], wherein the biodegradable plastic material is a biodegradable polyester and a biodegradable polymer having an amino group and / or an amide bond. A biodegradable plastic molded product according to the above [11], which is a mixture of a copolymer or biodegradable polyester and a biodegradable polymer having an amino group and / or an amide bond,
[14] The biodegradable plastic molded product according to the above [11], which is a housing for electric appliances, [15] the acid value of the biodegradable plastic material treated with a compound capable of reacting with active hydrogen is 0.5. The biodegradable plastic molded product according to the above [11], wherein the temperature is 80
Even when aged for 48 hours under constant temperature and humidity conditions of 80 ° C and 80% relative humidity, the increase in acid value is 0.2 or less and the decrease in molecular weight is within 10%. [11] The biodegradable plastic molded product described in [17], wherein the active hydrogen is selected from a carboxyl group, a hydroxyl group, an amino group and an amide bond in the biodegradable plastic material 1.
One or two or more atomic groups, characterized in that the biodegradable plastic molding according to the above [11], [1
8] The biodegradable plastic molded product according to [11] above, wherein the compound capable of reacting with active hydrogen is a cross-linking agent having a carbodiimide group. [19] The cross-linking agent having a carbodiimide group is dicyclohexyl. The biodegradable plastic molded product according to [18] above, which is carbodiimide or diisopropylcarbodiimide, and [20] the biodegradable product according to [11], which contains silicates. Plastic moldings,
[21] The biodegradable plastic molded product according to the above [20], wherein the content of the silicates is 5 to 30% by weight based on the whole biodegradable plastic molded product.
[22] A method for producing a biodegradable plastic molded article, which comprises adding a compound capable of reacting with active hydrogen to a biodegradable plastic material before, during or after melting, mixing and molding the material. 23] The method for producing a biodegradable plastic molded article according to [22] above, wherein the molding is performed by film molding, extrusion molding or injection molding, [24] before being melted into a biodegradable plastic material A method for producing a biodegradable plastic molded article, which comprises molding a compound capable of reacting with active hydrogen and a silicate at the time of melting or after melting, simultaneously or separately and mixing, [25] molding The method for producing a biodegradable plastic molded product according to the above [24], which is carried out by film molding, extrusion molding or injection molding.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The definition of a biodegradable plastic used in the present invention is a plastic which is decomposed into low molecular weight compounds, and finally water and carbon dioxide, by the involvement of microorganisms in the natural world after use (biodegradation). Plastics Study Group,
ISO / TC-207 / SC3). As a biodegradable polymer that is a raw material for such biodegradable plastics,
For example, polysaccharide derivatives such as cellulose, starch, dextran, chitin, peptides such as collagen, casein, fibrin, gelatin, etc., such as polyamino acids,
For example, polyvinyl alcohol, for example, polyamide such as nylon 4, nylon 2 / nylon 6 copolymer, for example, polyglycolic acid, polylactic acid, polysuccinic acid ester, polyoxalic acid ester, polyhydroxybutyric acid, butylene polydiglycolate, polycaprolactone, polydioxanone, etc. There are many kinds, and they can be used in the present invention. That is, the biodegradable polymer is an organic material that is decomposed and assimilated by the action of the natural world or a living body, is an ideal material suitable for the environment, and may be any material as long as the object of the present invention is not impaired. Absent. Of these, biodegradable polyester is particularly preferable.

The biodegradable plastic used in the present invention is a biodegradable polyester or a copolymer of a biodegradable polyester and a biodegradable polymer having an amino group and / or an amide bond, as long as the object of the present invention is not impaired. It may be a combination or a mixture of a biodegradable polyester and a biodegradable polymer having an amino group and / or an amide bond. Examples of the biodegradable polymer having an amino group and / or an amide bond include polyamino acids and biodegradable polyamides such as nylon.

The biodegradable polyester used in the present invention is a polymer having an ester bond; -CO-O- in its main chain. The biodegradable polyester used in the present invention is metabolized by, for example, a microorganism. Examples of the polyesters include aliphatic polyester resins having moldability, heat resistance, and impact resistance. Examples of the aliphatic polyester resin include polyoxalic acid ester, polysuccinic acid ester, polyhydroxybutyric acid, butylene polydiglycolate, polycaprolactone, polydioxanone, such as polymers of oxyacids such as lactic acid, malic acid or glycolic acid, or copolymers thereof. Examples thereof include hydroxycarboxylic acid-based aliphatic polyester resins such as polymers. Of these, a hydroxycarboxylic acid-based aliphatic polyester resin typified by polylactic acid is particularly preferable.

The biodegradable polyester used in the present invention can be synthesized according to a method known per se. Examples thereof include lactide method, polycondensation of polyhydric alcohol and polybasic acid, and intermolecular polycondensation of hydroxycarboxylic acid having a hydroxyl group and a carboxyl group in the molecule.

The lactide method is a method by ring-opening polymerization of cyclic diesters and corresponding lactones. Examples of such cyclic diesters include, for example, lactide,
Glycolide and the like, and examples of the lactone include ε-caprolactone, β-propiolactone, γ-butyrolactone, δ-valerolactone and the like.

Examples of the polyhydric alcohol used in the polycondensation of polyhydric alcohol and polybasic acid include, for example, ethylene glycol, diethylene glycol and triethylene glycol.
, Propylene glycol, neopentyl glycol,
1,3-butanediol, 1,4-butanediol,
Examples of the polybasic acid used therein include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid and naphthalenedicarboxylic acid, such as adipic acid and sebacic acid. , Oxalic acid, succinic acid, succinic anhydride, maleic acid,
Alienic dicarboxylic acids such as maleic anhydride, fumaric acid, and dimer acid, for example, alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid can be exemplified as a representative example, but in the present invention, it is an aliphatic polyester. It is preferable that both the polyhydric alcohol and the polybasic acid that are the raw materials,
It is preferably an aliphatic compound.

The intermolecular polycondensation of the hydroxycarboxylic acid having a hydroxyl group and a carboxyl group in the molecule can be obtained by the through-condensation dehydration condensation method of the corresponding hydroxycarboxylic acid. Examples of such a hydroxycarboxylic acid include lactic acid, 2-hydroxyacetic acid, 2-hydroxypropanoic acid, 2-hydroxybutyric acid, 2-hydroxyvaleric acid, 2-hydroxyhexanoic acid, 2-hydroxyheptanoic acid, 2-hydroxyoctane. Acid, 2-hydroxy-2-methylpropanoic acid, 2-hydroxy-2-methylbutyric acid, 2-hydroxy-2-ethylbutyric acid, 2-hydroxy-2-methylvaleric acid, 2-hydroxy-2-ethylvaleric acid, 2-hydroxy-2-propylvaleric acid, 2-
Hydroxy-2-butylvaleric acid, 2-hydroxy-2-
Methylhexanoic acid, 2-hydroxy-2-ethylhexanoic acid, 2-hydroxy-2-propylhexanoic acid, 2-
Hydroxy-2-butylhexanoic acid, 2-hydroxy-
2-pentylhexanoic acid, 2-hydroxy-2-methylheptanoic acid, 2-hydroxy-2-ethylheptanoic acid,
2-hydroxy-2-propylheptanoic acid, 2-hydroxy-2-butylheptanoic acid, 2-hydroxy-2-pentylheptanoic acid, 2-hydroxy-2-hexylheptanoic acid, 2-hydroxy-2-methyloctanoic acid, 2-
Hydroxy-2-ethyloctanoic acid, 2-hydroxy-
2-propyloctanoic acid, 2-hydroxy-2-butyloctanoic acid, 2-hydroxy-2-pentyloctanoic acid, 2-hydroxy-2-hexyloctanoic acid, 2-hydroxy-2-heptyloctanoic acid, 3-hydroxypropane Acid, 3-hydroxybutanoic acid, 3-hydroxypentanoic acid, 3-hydroxyhexanoic acid, 3-hydroxyheptanoic acid, 3-hydroxyoctanoic acid, 3-hydroxy-3-methylbutanoic acid, 3-hydroxy-3-methylpentanoic acid , 3-hydroxy-3-ethylpentanoic acid,
3-hydroxy-3-methylhexanoic acid, 3-hydroxy-3-ethylhexanoic acid, 3-hydroxy-3-propylhexanoic acid, 3-hydroxy-3-methylheptanoic acid, 3-hydroxy-3-ethylheptanoic acid, 3-hydroxy-3-propylheptanoic acid, 3-hydroxy-3
-Butylheptanoic acid, 3-hydroxy-3-methyloctanoic acid, 3-hydroxy-3-ethyloctanoic acid, 3-
Hydroxy-3-propyloctanoic acid, 3-hydroxy-3-butyloctanoic acid, 3-hydroxy-3-pentyloctanoic acid, 4-hydroxybutanoic acid, 4-hydroxypentanoic acid, 4-hydroxyhexanoic acid, 4-hydroxyheptane Acid, 4-hydroxyoctanoic acid, 4-hydroxy-4-methylpentanoic acid, 4-hydroxy-4-
Methylhexanoic acid, 4-hydroxy-4-ethylhexanoic acid, 4-hydroxy-4-methylheptanoic acid, 4-hydroxy-4-ethylheptanoic acid, 4-hydroxy-4
-Propylheptanoic acid, 4-hydroxy-4-methyloctanoic acid, 4-hydroxy-4-ethyloctanoic acid, 4
-Hydroxy-4-propyloctanoic acid, 4-hydroxy-4-butyloctanoic acid, 5-hydroxypentanoic acid, 5-hydroxyhexanoic acid, 5-hydroxyheptanoic acid, 5-hydroxyoctanoic acid, 5-hydroxy-5
-Methylhexanoic acid, 5-hydroxy-5-methylheptanoic acid, 5-hydroxy-5-ethylheptanoic acid, 5-
Hydroxy-5-methyloctanoic acid, 5-hydroxy-
5-ethyloctanoic acid, 5-hydroxy-5-propyloctanoic acid, 6-hydroxyhexanoic acid, 6-hydroxyheptanoic acid, 6-hydroxyoctanoic acid, 6-hydroxy-6-methylheptanoic acid, 6-hydroxy-6- An aliphatic hydroxycarboxylic acid such as methyloctanoic acid, 6-hydroxy-6-ethyloctanoic acid, 7-hydroxyheptanoic acid, 7-hydroxyoctanoic acid, 7-hydroxy-7-methyloctanoic acid, or 8-hydroxyoctanoic acid, and Mention may be made of oligomers derived from them.

Examples of the catalyst for producing the hydroxycarboxylic acid type aliphatic polyester resin include tin, antimony, zinc, titanium, iron and aluminum compounds. Among them, tin type catalysts and aluminum type catalysts are preferable, Tin octylate and aluminum acetylacetonate are particularly suitable.

Among the above-mentioned hydroxycarboxylic acid type aliphatic polyester resins, poly-L-lactic acid obtained by lactide ring-opening polymerization is hydrolyzed to L-lactic acid and its safety is also confirmed, which is particularly preferable. However, the hydroxycarboxylic acid-based aliphatic polyester resin used in the present invention is not limited to this, and therefore the lactide used for its production is not limited to the L form.

Examples of the compound capable of reacting with active hydrogen according to the present invention include a carboxylic acid and a hydroxyl group which are terminal functional groups of a polyester resin, or an amino group of a biodegradable polymer contained as a copolymer or a mixture, or Also, compounds having reactivity with hydrogen of amide bond, such as carbodiimide compounds, isocyanate compounds, or oxazoline compounds can be applied. Particularly, carbodiimide compounds can be melt-kneaded with polyester, and hydrolysis can be adjusted by adding a small amount. Therefore, it is preferable. Also,
These compounds capable of reacting with active hydrogen may be used alone or in combination of two or more kinds.

The carbodiimide compound is a cross-linking agent having a carbodiimide group, and is a compound (including a polycarbodiimide compound) having one or more carbodiimide bonds: -N = C = N- in the molecule. As the production method thereof, for example, an organic phosphorus compound (O, O-dimethyl-O- (3-methyl-4-nitrophenyl) phosphorothioate, O, O-dimethyl-O- (3-methyl-4-) as a catalyst is used. (Methylthio) phenyl) phosphorothioate,
O, O-diethyl-O-2-isopropyl-6-methylpyrimidin-4-yl phosphorothioate etc.) or an organometallic compound (rhodium complex, titanium complex, tungsten complex, palladium complex etc.) and various polyisocyanates of about 70 Examples thereof include those that can be synthesized by subjecting to a decarboxylation condensation reaction in a solvent-free or inert solvent (hexane, benzene, dioxane, chloroform, etc.) at a temperature of about C or higher.

Examples of the monocarbodiimide compound contained in the carbodiimide compound include dicyclohexylcarbodiimide, diisopropylcarbodiimide, dimethylcarbodiimide, diisobutylcarbodiimide, dioctylcarbodiimide, t-butylisopropylcarbodiimide, diphenylcarbodiimide, di-t-butylcarbodiimide, or di-β. Examples thereof include naphthylcarbodiimide, and among these, dicyclohexylcarbodiimide or diisopropylcarbodiimide is particularly preferable in terms of industrial availability.

Examples of the polyisocyanate compound include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate and 2,4'-diphenylmethane. Diisocyanate, 2,2'-diphenylmethane diisocyanate, 3,3'-dimethyl-4,4'-biphenylene diisocyanate, 3,3'-dimethoxy-
4,4'-biphenylene diisocyanate, 3,3'-
Dichloro-4,4'-biphenylene diisocyanate,
1,5-naphthalene diisocyanate, 1,5-tetrahydronaphthalene diisocyanate, tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, dodecamethylene diisocyanate, trimethylhexamethylene diisocyanate, 1,3-cyclohexylene diisocyanate, 1,4-cyclohexylene Diisocyanate, xylylene diisocyanate, tetramethyl xylylene diisocyanate, hydrogenated xylylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate or 3,3'-dimethyl-4,
4'-dicyclohexyl methane diisocyanate etc. are mentioned. In the present invention, a commercially available polyisocyanate compound is used in the examples, and aromatic isocyanate adducts such as coronate (manufactured by Nippon Polyurethane; hydrogenated diphenylmethane diisocyanate) or mylionate (manufactured by Nippon Polyurethane) are applicable, In the case of melt blending, it is a solid rather than a liquid, for example, a masking agent for isocyanate groups (polyhydric aliphatic alcohol, aromatic polyol, etc.)
The use of polyisocyanate compounds blocked with is preferred.

Examples of the oxazoline compound include:
2,2'-o-phenylene bis (2-oxazoline),
2,2'-m-phenylene bis (2-oxazoline),
2,2'-p-phenylene bis (2-oxazoline),
2,2'-p-phenylenebis (4-methyl-2-oxazoline), 2,2'-m-phenylenebis (4-methyl-2-oxazoline), 2,2'-p-phenylenebis (4, 4'-dimethyl-2-oxazoline), 2,
2'-m-phenylene bis (4,4'-dimethyl-2-
Oxazoline), 2,2'-ethylenebis (2-oxazoline), 2,2'-tetramethylenebis (2-oxazoline), 2,2'-hexamethylenebis (2-oxazoline), 2,2'-octa Methylenebis (2-oxazoline), 2,2'-ethylenebis (4-methyl-2-)
Oxazoline), or 2,2′-diphenylenebis (2-oxazoline).

The method of treating a biodegradable plastic with a compound capable of reacting with active hydrogen in the biodegradable plastic is usually a method of melting a compound capable of reacting with active hydrogen in the biodegradable plastic before, during or after melting. It is carried out by adding, melting and mixing. The amount of the compound capable of reacting with active hydrogen is about 0.1 of the biodegradable plastic.
It is preferably about 5% by weight. However, the long-term reliability of the biodegradable plastic material treated with the compound capable of reacting with active hydrogen of the present invention and the biodegradation rate after use are delayed depending on the type and the amount of the compound capable of reacting with the active hydrogen. The amount of the compound and the amount of the compound capable of reacting with the active hydrogen to be compounded may be determined according to the intended product. The compounds capable of reacting with active hydrogen may be used alone or in combination of two or more.

As mentioned above, the biodegradable plastic and the compound capable of reacting with active hydrogen may be mixed before, during or after the melting of the biodegradable plastic. That is, it does not matter if it is melted and sufficiently mixed with a compound capable of reacting with active hydrogen.

In order to quantify active hydrogen in the biodegradable plastic treated with a compound capable of reacting with active hydrogen, for example, a method of measuring the amount of residual fatty acid, that is, the acid value can be mentioned. In the present invention, a biodegradable polyester is mainly used as a material, and a carboxyl group and a hydroxyl group are present in the material. Measuring the acid value means quantifying the carboxyl groups in the biodegradable polyester, and thus quantifying active hydrogen for convenience. What is the acid value?
It is the number of mg of potassium hydroxide required to neutralize the free fatty acid contained in 1 g of fat such as fatty acid. Hereinafter, one preferable mode for measuring the acid value will be described.

As a reagent for measuring the acid value, 0.02
N KOH-EtOH (KOH is potassium hydroxide, EtOH is ethanol. The same applies hereinafter) solution, phenolphthalein solution and phenol red solution are used. The method for preparing each solution is described below.

As a preferred method for preparing a 0.02N KOH-EtOH solution, about 0.35 g of potassium hydroxide (KOH) is dissolved in 5 mL of deionized water and EtOH is added to make 250 mL,
Place in a container tightly closed with a glass or rubber stopper and leave for 24 hours. Immediately incline the supernatant into another shaded bottle and seal with a rubber stopper. Store tightly closed in a light-proof bottle. The reagent is then standardized with 0.02N hydrochloric acid. Accurately measure 5 mL of 0.02N hydrochloric acid, add 10 mL of deionized water,
For example, 2 drops of a phenolphthalein reagent is added as an indicator, and titrated with a prepared 0.02N KOH-EtOH solution until a pink color is obtained, and the factor is calculated.

One preferred method for preparing the phenolphthalein solution is 0.025 g of phenolphthalein.
Dissolve in 22.5 mL of EtOH (95%) and add 25 with deionized water.
The method of making it into mL is mentioned. This reagent is the pH of the solution
Is colorless at pH 8.3 or lower, and pH 8.3-10.
At 0, a red color is exhibited.

One preferred method for preparing the phenol red solution is to add 0.025 g of phenol red to EtOH (95
%) Dissolved in 5 mL and made to be 25 mL with ion-exchanged water. This reagent exhibits a yellow color when the pH of the solution is 6.8 or lower, and a red color when the pH is 8.4 or higher.

As a preferred embodiment for measuring the acid value using the prepared reagent, as a biodegradable polyester material, for example, polylactic acid (0.1 mg) is precisely weighed, dissolved in chloroform (10 mL), and benzyl alcohol (10 mL) is added. Add. Using phenol red as an indicator, 0.02
An example is a method in which the end point is the point at which the color changes from yellow to pink in the N KOH-EtOH solution. The volume at this time is VmL. Similarly, blank benzyl alcohol 10m
Also measure 10 mL of L + chloroform. The volume at this time is V ₀ mL.

The weight (mg) of KOH necessary for neutralizing the free fatty acid contained in 1 g of the sample is determined by the following formula. AV (acid value) = {(V−V ₀ ) × 0.02 × F × 56.
11} / S In the above formula, F is the factor of the 0.02N KOH-EtOH solution, and V is the volume (m of the 0.02N KOH-EtOH solution required for measuring the sample.
L) and V ₀ represent the volume (mL) of the 0.02N KOH-EtOH solution required for titration of the blank, and S represents the sample weight (g).

Another method for quantifying active hydrogen in biodegradable plastics treated with a compound capable of reacting with active hydrogen is a method of reacting with a Grignard reagent. Unlike the previous method, this method can quantify not only carboxyl groups but also hydroxyl groups, amino groups, etc., and therefore can be applied to a copolymer of polyester and polyamide or a mixture of polyester and polyamide. Active hydrogen quantitatively reacts with methylmagnesium iodide to generate methane. This reaction is carried out in a reaction vessel of an active hydrogen quantification device, the generated methane gas is collected in a gas buret, and the volume thereof is measured, whereby the active hydrogen can be quantified. Examples of the Grignard reagent include not only methylmagnesium iodide but also known Grignard reagents such as phenylmagnesium bromide, ethylmagnesium chloride, propylmagnesium chloride and butylmagnesium chloride.

The acid value of the biodegradable plastic material treated with a compound capable of reacting with active hydrogen before aging is preferably about 0.5 or less. When it is about 0.5 or less, hydrolysis of the biodegradable plastic due to active hydrogen is less likely to occur, and the biodegradable plastic that can withstand aging for 48 hours under constant temperature and humidity conditions of 80 ° C and 80%. You can get the material.

The increase in acid value after aging in the biodegradable plastic material treated with the compound capable of reacting with active hydrogen is preferably about 0.2 or less. Further, the decrease in the molecular weight is preferably within 10%. Within these ranges, long-term reliability when used in a casing of an electric product can be secured.

The biodegradable plastic material of the present invention is a reinforcing material, as long as the acid value before aging does not exceed 0.5.
In addition to inorganic or organic fillers, antioxidants, heat stabilizers, UV absorbers, etc., lubricants, waxes, colorants, crystallization accelerators, degradable organic substances such as starch, etc. may be used in combination. , And may be used alone or in combination.

As the reinforcing material, for example, glass micro beads, carbon fiber, chalk, for example, novoculite.
(novoculite) like quartz, asbestos, feldspar, mica,
Examples thereof include silicates such as talc and wollastonite, kaolin and the like. As the inorganic filler, for example, carbon, silicon dioxide, alumina, silica, magnesia,
Alternatively, metal oxide fine particles such as ferrite, for example, talc,
Mica, kaolin, silicates such as zeolite, fine particles such as barium sulfate, calcium carbonate, or fullerene, and as the organic filler, for example, epoxy resin, melamine resin, urea resin, acrylic resin, phenol resin, polyimide resin, Examples thereof include polyamide resin, polyester resin, and Teflon (registered trademark) resin. Of these, carbon and silicon dioxide are preferable. The fillers may be used alone or in combination of two or more. Silicates as an inorganic filler also function as a flame retardant. Further, the content of the reinforcing material may be appropriately selected according to the type, and cannot be generally stated. For example, when the reinforcing material is a silicate, its content is preferably about 5 to 30% by weight based on the entire biodegradable plastic material according to the present invention.

Examples of the antioxidant include phenol-based, amine-based, phosphorus-based, sulfur-based, hydroquinone-based,
Alternatively, quinoline-based antioxidants and the like can be mentioned. Phenolic antioxidants 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-
C such as hexanediol-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate]
_2-10 alkylene diol - bis [3- (3,5-di - branched C _3-6 alkyl-4-hydroxyphenyl) propionate], for example, triethylene glycol - bis [3-
(3-t-butyl-5-methyl-4-hydroxyphenyl) propionate] and other di- or trioxy C _2-4 alkylenediol-bis [3- (3,5-di-branched C _3-
6 alkyl-4-hydroxyphenyl) propionate], for example glycerin tris [3- (3,5-di-t
-Butyl-4-hydroxyphenyl) propionate]
C _3-8 alkanetriol-bis [3- (3,5-
Di-branched C _3-6 alkyl-4-hydroxyphenyl) propionate], for example, C _4-8 alkanetetra, such as pentaerythritol tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] Alltetrakis [3- (3,5-di-branched _C3-6 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 '
-Hexamethylenebis (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), or 1,1,3-tris (2-methyl-4-hydroxy-5-t-butylphenol) butane. Examples of amine-based antioxidants include phenyl-1-naphthylamine, phenyl-2-naphthylamine, N, N′-diphenyl-1,
4-phenylenediamine, or N-phenyl-N'-
Examples thereof include cyclohexyl-1,4-phenylenediamine. As the phosphorus-based antioxidant, for example, triisodecyl phosphite, triphenyl phosphite, trisnonyl phenyl phosphite, diphenyl isodecyl phosphite, phenyl diisodecyl phosphite,
2,2-methylenebis (4,6-di-t-butylphenyl) octylphosphite, 4,4'-butylidenebis (3-methyl-6-t-butylphenyl) ditridecylphosphite, 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 compounds such as phosphite and tris (2-t-butyl-4-phenylphenyl) phosphite; triethylphosphine, tripropylphosphine, tributylphosphine, tricyclohexylphosphine, diphenylvinylphosphine, allyldiphenylphosphine,
Triphenylphosphine, methylphenyl-p-anisylphosphine, p-anisyldiphenylphosphine, 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-p-tolylphosphine, tri-o-anisylphosphine, tri-p-
Examples thereof include anisylphosphine and phosphine compounds such as 1,4-bis (diphenylphosphino) butane. Examples of the hydroquinone antioxidant include 2,
5-di-t-butylhydroquinone and the like can be mentioned. Examples of the quinoline antioxidant include 6-ethoxy-2,
2,4-trimethyl-1,2-dihydroquinoline and the like can be mentioned, and examples of the sulfur-based antioxidant include dilauryl thiodipropionate, distearyl thiodipropionate and the like. Among them, preferable antioxidants include phenolic antioxidants (particularly, hindered phenols) such as polyol-poly [(branched C
_3-6 alkyl group- and hydroxy group-substituted phenyl) propionate] and the like. 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 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 methylene chloride low-polymerization products; waxes such as paraffin wax and polyethylene wax; higher aliphatic alcohols, higher aliphatic amides, higher fatty acid esters, higher fatty acid salts, and molybdenum disulfide. Among these, it is particularly preferable to use a silicon copolymer (a resin obtained by polymerizing silicon by block or graft). As the silicone copolymer, acrylic resin, polystyrene resin, polynitrile resin, polyamide resin, polyolefin resin,
Epoxy-based resin, polybutyral-based resin, melamine-based resin, vinyl chloride-based resin, polyurethane-based resin, polyvinyl ether-based resin, or the like may be obtained by block- or graft-polymerizing silicon, and a silicon-grafted copolymer is used. Is preferred. 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 and polyethylene wax, paraffin wax, Fischer-Tropsch wax, microcrystalline wax, montan wax, fatty acid amide wax, higher aliphatic alcohol wax, and higher wax. Examples thereof include fatty acid wax, fatty acid ester wax, carnauba wax, rice wax and the like. 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.

By molding the biodegradable plastic material used in the present invention, a biodegradable plastic molded product can be obtained. The biodegradable plastic molded product can be used, for example, in a housing for electric products such as a radio, a microphone, a TV, a keyboard, a portable music player, and a personal computer.

Using the biodegradable plastic material of the present invention as a raw material, for example, a casing of an electric product may be manufactured according to a manufacturing method known per se. Various known means for molding can be selected depending on the type of molded article. Examples of the molding method include film molding, extrusion molding, and injection molding. Among them, injection molding is particularly preferable. Extrusion molding or injection molding is carried out according to a conventional method, for example, an extruder such as a single-screw extruder, a multi-screw extruder, a tandem extruder, or the like known in itself, or, for example, an in-line screw-type injection molding machine, a multi-layer injection molding machine, two-headed injection molding machine. It can be performed by an injection molding machine such as a type injection molding machine, and is molded into a desired shape.

As one preferable method of molding, the biodegradable plastic and a compound capable of reacting with active hydrogen are
Approximately 500 rpm with a Henschel mixer of approximately 20 L
The mixture is mixed for about 2 minutes, and then melt-kneaded with a twin-screw extruder adjusted to about 220 ° C. to obtain pellets. Using the pellets, for example, a housing for electric appliances is manufactured according to a conventional method.

[0053]

EXAMPLE An example was actually carried out as a biodegradable polyester according to the present invention, but the present invention is not limited to this. The molecular weight in the examples is
The weight average molecular weight (polystyrene-equivalent molecular weight) was measured by gel permeation chromatography (GPC). Equipment: MILLPORE Waters600E system controller Detector: UV (Waters484) and RI (Waters410) Standard sample: Dissolve the sample in chloroform so that the polystyrene concentration becomes 0.15% by weight, and stir for about 2 hours. 0.25μ
The sample was passed through a filter of m.

[Example 1] 1% by weight of carbodiimide (trade name: Carbodilite 10B, manufactured by Nisshinbo Co., Ltd.) was added to polylactic acid (trade name: Resia H100J, manufactured by Mitsui Chemicals) as a compound capable of reacting with active hydrogen. The mixture was kneaded at a kneading temperature of 185 ° C. for 5 minutes. The acid value was reduced from 1.8 to 0.1. The kneaded product was formed into a plate having a size of 5 cm square and a thickness of 1 mm, and was aged under the conditions of 80 ° C. and 80% humidity for 48 hours. Acid value increase of 0.2 or less, and molecular weight decrease of 10
It was within%.

Example 2 In the same manner as in Example 1, the amount of carbodiimide added was changed to 0.5% by weight or 0.8% by weight and kneading was performed to prepare a test piece. Carbodiimide 0.5
The acid value was 0.8 when the weight% was added, and the acid value was 0.5 when the 0.8 weight% was added. When aged at 80 ° C. and 80% humidity for 48 hours, in the sample to which 0.8% by weight of carbodiimide was added, the increase in acid value was 0.2 or less, and the decrease in molecular weight was within 10%. On the other hand, in the case of the sample containing 0.5% by weight of carbodiimide, the acid value increased from 0.8 to 5.2 and the molecular weight decreased by 60%.

Example 3 Regarding carbodiimide (trade name: Cell Green, grade: PH, manufactured by Daicel Chemical) and polybutylene succinate (trade name: Bionore # 1000, manufactured by Showa High Polymer Co., Ltd.), 1% by weight of carbodilite 10B, manufactured by Nisshinbo Co., Ltd. was added to prepare a kneaded product in the same manner as in Example 1. The acid values of the kneaded product were 0.4 and 0.2, respectively. 80 ℃,
After aging for 48 hours at a humidity of 80%, the increase in acid value was 0.2 or less and the decrease in molecular weight was within 10% in both cases.

Example 4 In place of carbodiimide, 1% by weight of block type polyurethane (manufactured by Nippon Polyurethane Co., Ltd., Millionate MS50, amount of isocyanate group: 15%) was added, and the test piece was prepared in the same manner as in Example 1. It was made. The acid value was reduced to 0.2. Aging was carried out under the same conditions as in Example 1, but the increase in acid value was 0.2 or less, and the decrease in molecular weight was within 10%.

Example 5 With respect to the test piece of Example 1,
Humidity is kept constant at 80% and temperature is 85, 80, 75, 7
Aging was performed while changing the temperature to 0 and 65 ° C., and the acid value and the change in molecular weight were measured. At 85 ° C, no change occurred until 48 hours, but after 72 hours, the acid value increased to 0.8, and after 96 hours, the acid value increased to 5.1 and the molecular weight decreased by 60%. Therefore, at 85 ° C., the increase in acid value was 0.2 or less and the decrease in molecular weight was within 10% after aging for 3 days. Similarly, at 80 ° C for 5 days, 7
8 days at 5 ° C, 14 days at 70 ° C, 2 days at 65 ° C
The increase in acid value was 0.2 or less and the decrease in molecular weight was within 10% for 0 days.

On the basis of the results of Example 5, the increase in acid value was 0.
Time less than 2 and decrease of molecular weight within 10% (day)
FIG. 1 (a) shows a plot of temperature and temperature. Also,
It is known that the logarithm of the reaction rate is proportional to the reciprocal of temperature (1 / temperature) (Arrhenius equation), and in FIG. 1 (b), the reciprocal of temperature (1 / temperature) and time are calculated according to this law. The logarithm of and was plotted (Arrhenius plot). This plot shows a linear relationship, and from the slope and the intercept, the relational expression of the time and the temperature until the change in the acid value and the molecular weight is observed can be obtained by the following expression. t = (10 ^{5070 × (1 / 273.15 + temperature (℃))-13.664} )
/ 365 (In the formula, t is the time (year) until a change in acid value and molecular weight is observed.) From this formula, when aging at 30 ° C and 80% humidity, the acid value increases and the molecular weight decreases. It took 3.2 years to observe. Therefore, if a compound capable of reacting with active hydrogen is added to control the acid value to 0.5 or less, it is expected that the physical properties can be secured for at least 3 years in an environment of at least 30 ° C. and 80% relative humidity.

Example 6 Similar to Example 5, the same experiment was conducted by changing the addition amount of carbodiimide to 2% by weight. As in FIG. Fig. 2 (a) shows a plot of the time (day) and the temperature at which the decrease of 10% is within 10%. Further, the Arrhenius plot is shown in FIG. Similarly to the above, this plot shows a linear relationship, and from the slope and the intercept, the relational expression of the time and the temperature until the change of the acid value and the molecular weight is obtained by the following expression. t = (10 ^{5312 × (1 / 273.15 + temperature (℃))-14.065} )
/ 365 (In the formula, t is the time (year) until a change in acid value and molecular weight is observed.) From this formula, when aging at 30 ° C and 80% humidity, the acid value increases and the molecular weight decreases. It took 7.9 years to observe. Set the initial acid value to 0.5 or less,
By doubling the amount of the compound capable of reacting with active hydrogen as compared with Example 5, it is expected that the physical properties can be maintained for 8 years under the aging conditions of Example 1, and the amount of the compound capable of reacting with active hydrogen is adjusted. Therefore, it was found that the guarantee period of physical properties can be set according to the life of the product.

Regarding the sample at each temperature of Example 6, the change in acid value with time at each temperature and 80% humidity is shown in FIG. 3 (a), and the change in molecular weight is shown in FIG.
It is shown in (b). From Example 6, it was found that the guaranteed period of physical properties can be set according to the life of the product by adjusting the amount of the additive. Furthermore, from FIG. 3, after a certain holding time, hydrolysis was performed. Was accelerated and it was found to exhibit good biodegradability. Also, its hydrolyzability is
It was equivalent to the case where no compound capable of reacting with active hydrogen was contained (biodegradable polyester). That is, the physical properties are retained during the use period, and when the physical property retention period ends,
It was found that biodegradability equivalent to that of biodegradable polyester can be expressed.

Comparative Example 1 As in Example 1, two kinds of polylactic acid (manufactured by Mitsui Chemicals and Shimadzu Corporation) were aged under the same conditions as in Example 1 without adding a compound capable of reacting with active hydrogen. I went. Each acid value is 1.
It was 8. After aging, the molecular weight is 60%.
Since it was lowered and the bending strength was reduced to 1/10, it could not be used as a case at all.

Comparative Example 2 Polycaprolactone used in Example 3 (trade name: cell green, grade: PH,
Daicel Chemical Industries), polybutylene succinate (trade name: Bionole # 1000, Showa High Polymer),
A kneaded product was prepared in the same manner as in Example 1 without adding a compound capable of reacting with active hydrogen. Same conditions as in Example 1 (80 ° C.,
As a result of aging at a humidity of 80% for 48 hours), the molecular weight was reduced by 80%, so it could not be used as a case at all.

[0064]

The biodegradable plastic material of the present invention is
Biodegradable plastic that does not use fossil raw materials,
In particular, the composition ensures the storage stability of the biodegradable polyester (3 years at 30 ° C. and 80% humidity), and can be put to practical use for durable materials such as electric appliances and computer casings. This biodegradable plastic molded article shows, after the storage stability period has elapsed, substantially the same hydrolyzability as in the state in which there is no compound capable of reacting with active hydrogen, and in a culture solution containing microorganisms or in soil. Decomposes and disappears. As a result, the volume of waste can be reduced. It is also useful because it can be manufactured by a simple operation.

[Brief description of drawings]

FIG. 1 (a) is an increase in acid value of 0.2 in Example 5.
It is the figure which plotted the time (day) and the temperature (degreeC) which are below and the fall of molecular weight is 10% or less. (B) The logarithm of the time when the increase in the acid value is 0.2 or less and the decrease in the molecular weight is within 10% in Example 5 (log
(Day)) and the reciprocal of temperature (1 / temperature: 1 / K) are plotted.

2 (a) The acid value increase in Example 6 is 0.2.
It is the figure which plotted the time (day) and the temperature (degreeC) which are below and the fall of molecular weight is 10% or less. (B) Logarithm of the time when the increase in the acid value is 0.2 or less and the decrease in the molecular weight is within 10% in Example 6 (log
(Day)) and the reciprocal of temperature (1 / temperature: 1 / K) are plotted.

FIG. 3 (a) is a graph plotting the change in acid value with respect to the retention time (day) of the physical properties of the biodegradable polyester at each temperature in Example 6. In the figure, the black squares are the results of aging at 85 ° C., the open diamonds at 80 ° C., the open triangles at 75 ° C., and the open squares at 70 ° C. Relative humidity is 80
%. (B) It is the figure which plotted the weight average molecular weight reduction rate (%) with respect to the retention time (day) of the physical properties of the biodegradable polyester at each temperature in Example 6. In the figure, the black square is 85
C., the open diamonds are 80.degree. C., the open triangles are 75.degree. C., and the open squares are 70.degree. The relative humidity is 80%.

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) C08K 3/34 C08K 3/34 5/29 5/29 C08L 67/00 C08L 67/00 (72) Inventor Hiroyuki Mori Tokyo 6-735 Kita-Shinagawa, Shinagawa-ku, Sony Corporation (72) Inventor Tsutomu Noguchi 6-35-35, Kita-Shinagawa, Shinagawa-ku, Tokyo F-term (reference) 4F071 AA01 AA43 AA81 AB26 in Sony Corporation AC12 AC19 AE02 AF52 AH05 AH12 4J002 CF001 CF181 CF191 DJ007 ER006 EU226 FD206

Claims (25)

[Claims] 1. A biodegradable plastic material treated with a compound capable of reacting with active hydrogen in the biodegradable plastic. 2. The biodegradable plastic material according to claim 1, wherein the biodegradable plastic material is a biodegradable polyester material. 3. The biodegradable plastic material has a copolymer of a biodegradable polyester and a biodegradable polymer having an amino group or / and an amide bond, or a biodegradable polyester and an amino group or / and an amide bond. The biodegradable plastic material according to claim 1, which is a mixture with a biodegradable polymer. 4. The biodegradable plastic material according to claim 1, wherein the biodegradable plastic material treated with the compound capable of reacting with active hydrogen has an acid value of 0.5 or less. 5. The acid value does not increase even after aging for 48 hours under constant temperature and humidity conditions of a temperature of 80 ° C. and a relative humidity of 80%.
The biodegradable plastic material according to claim 1, wherein the biodegradable plastic material has a molecular weight of 2 or less and a decrease in molecular weight of 10% or less. 6. The active hydrogen is derived from one or more atomic groups selected from a carboxyl group, a hydroxyl group, an amino group and an amide bond in the biodegradable plastic material. Biodegradable plastic material. 7. The biodegradable plastic material according to claim 1, wherein the compound capable of reacting with active hydrogen is a crosslinking agent having a carbodiimide group. 8. The biodegradable plastic material according to claim 7, wherein the crosslinking agent having a carbodiimide group is dicyclohexylcarbodiimide or diisopropylcarbodiimide. 9. The biodegradable plastic material according to claim 1, which contains silicates. 10. The biodegradable plastic material according to claim 9, wherein the content of silicates is 5 to 30% by weight based on the whole biodegradable plastic material. 11. A biodegradable plastic molded product obtained by molding a biodegradable plastic material treated with a compound capable of reacting with active hydrogen in the biodegradable plastic. 12. The biodegradable plastic material is a biodegradable polyester material.
The biodegradable plastic molded product according to item 1. 13. A biodegradable plastic material has a copolymer of a biodegradable polyester and a biodegradable polymer having an amino group and / or an amide bond, or a biodegradable polyester and an amino group or / and an amide bond. The biodegradable plastic molded product according to claim 11, which is a mixture with a biodegradable polymer. 14. The biodegradable plastic molded product according to claim 11, which is a housing for an electric product. 15. The biodegradable plastic molded product according to claim 11, wherein the biodegradable plastic material treated with the compound capable of reacting with active hydrogen has an acid value of 0.5 or less. 16. Even when aged for 48 hours under constant temperature and humidity conditions of a temperature of 80 ° C. and a relative humidity of 80%, an increase in acid value is 0.2 or less and a decrease in molecular weight is within 10%. The biodegradable plastic molded product according to claim 11. 17. The active hydrogen is derived from one or more atomic groups selected from a carboxyl group, a hydroxyl group, an amino group and an amide bond in a biodegradable plastic material. Biodegradable plastic molding. 18. The biodegradable plastic molded product according to claim 11, wherein the compound capable of reacting with active hydrogen is a crosslinking agent having a carbodiimide group. 19. The biodegradable plastic molded product according to claim 18, wherein the crosslinking agent having a carbodiimide group is dicyclohexylcarbodiimide or diisopropylcarbodiimide. 20. The biodegradable plastic molded product according to claim 11, which contains silicates. 21. The biodegradable plastic molded product according to claim 20, wherein the content of silicates is 5 to 30% by weight based on the whole biodegradable plastic molded product. 22. A method for producing a biodegradable plastic molded article, which comprises molding a biodegradable plastic material with a compound capable of reacting with active hydrogen added before, during or after melting, and then molding. . 23. The molding is performed by film molding, extrusion molding or injection molding.
The method for producing a biodegradable plastic molded article according to 1. 24. A biodegradable plastic material, characterized in that a compound capable of reacting with active hydrogen before, during or after melting and a silicate are added simultaneously or separately and mixed, and then molded. For producing flexible plastic moldings. 25. The molding according to claim 24, wherein the molding is performed by film molding, extrusion molding or injection molding.
The method for producing a biodegradable plastic molded article according to 1.