JP2002173584A - Biodegradable resin composition, packaging material, method for producing biodegradable resin composition and method for improving elastic modulus of the biodegradable resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a biodegradable resin composition having improved elastic modulus. SOLUTION: This resin is obtained by compounding polylactic acid as an aliphatic polyester resin with 5.0-20.0 wt.% natural mica, 0.5-5.0 wt.% aliphatic carboxylic acid amide as the organic nucleating agent and 0.1-2.0 wt.% carbodiimide compound as the hydrolysis suppressing agent for polylactic acid. As an example, 10 wt.% granulated mica powder having 40-50 μm particle diameter and obtained by granulating natural mica, 1 wt.% Carbodiright (R) and 1 wt.% ethylenebisstearic acid amide as the organic nucleating agent and compounded in polylactic acid (Tg: 60 deg.C); thereby the storage elastic modulus of this resin at 70-140 deg.C is much improved and, especially at about 100 deg.C to about 120 deg.C, is about 1×109. The biodegradable resin is useful as a raw material for household electric appliances and packaging materials and the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a biodegradable resin composition containing an aliphatic polyester resin as a main component and having an improved elastic modulus, a housing material comprising the biodegradable resin composition, and a biodegradable resin composition. The present invention relates to a method for producing a resin composition and a method for improving the elastic modulus of the biodegradable resin composition.

[0002]

2. Description of the Related Art The Used Electrical Appliance and Material Recycling Law is 2
Enforced in April, 2001, except for large-sized electrical products such as TVs (televisions), there is currently no collection and recycling of waste, and no legal regulations. For this reason, most electric products are discarded as non-combustible waste at the time of disposal. Even if the shape is small, a large number of sales results in a large amount of waste as a whole. This has become a serious problem in recent years when there is a shortage of waste disposal sites.

[0003] As a well-known treatment method, there is a method of shredding waste. However, this shredder treatment only reduces the volume of waste, and if it is landfilled, it will remain for decades or hundreds of years, and will not be a basic solution. It can also affect ecosystems. Even if material shredder dust is recycled, since all parts are finely crushed, for example, valuable materials (such as copper)
Is also mixed with other low-value materials, resulting in reduced purity and reduced recovery effect.

[0004] Therefore, first, a housing or a structure portion occupying a large part of the volume of an electric product is made of a biodegradable material, and the electronic component, the base and the like and the non-biodegradable portion are screwed or fitted, for example. By assembling it as an indented structure, it can be easily separated later. As a result, a part to be recycled can be separated into a part that can be discarded and a part that can be discarded as they are by a certain amount of dismantling processing, and these can be separately processed.

[0005] For example, the outermost surface of a housing of a radio, a microphone, a neck-mounted TV, a keyboard, a Walkman (registered trademark), a mobile phone, a radio-cassette, an earphone or the like is made of a biodegradable material. In this way, by preparing a portion that frequently comes into contact with the human body with a biodegradable material, it is possible to provide an electric product that is safer than a synthetic resin.

[0006] However, the biodegradable material is not limited to any kind, and a certain physical property is required for use as a housing or a structural material of an electric product.
First, under an atmosphere of 60 ° C. and 80% RH (relative humidity),
It is necessary to clear the condition that no deformation occurs even after holding for 00 hours.

At present, biodegradable plastics (biodegradable resins) can be roughly classified into three types: those having an aliphatic polyester resin in the molecular skeleton, those having a polyvinyl alcohol, and those having a polysaccharide. it can. Here, “biodegradable plastic” is defined as a plastic that is decomposed into low-molecular compounds by use of microorganisms in nature after use, and eventually decomposed into water and oxygen dioxide (biodegradable plastic). Workshop, ISO /
TC-207 / SC3).

[0008] Among these biodegradable plastics, aliphatic polyester resins (biodegradable polyester resins)
Has not been used for housings of electronic equipment and the like because it generally has a low melting point and does not have physical properties suitable for practical molded articles, particularly heat resistance. Phosphoric acid-based and sorbitol-based nucleating agents are known as crystal nucleating agents for improving the heat resistance and elastic modulus of the biodegradable resin. The effect was insufficient.

At present, biodegradable plastics are mainly made of aliphatic polyester resins, materials for agriculture, forestry and fisheries (films, plant pots, fishing lines, fish nets, etc.), civil engineering materials (water retention sheets, plant nets, etc.), packaging.・ Container field (Soil,
It is beginning to be used for foods and the like that are difficult to recycle due to adhesion.

In use, biodegradable plastics such as the above-mentioned biodegradable polyester resins have functions equivalent to those of conventional plastics, for example, strength, water resistance, moldability, heat resistance, and disposal. Sometimes they need to be rapidly degraded by microorganisms commonly found in nature.

[0011]

An aliphatic polyester resin, which is a conventional biodegradable plastic and does not contain any special additives, can be used alone for home electric appliances and housing materials in terms of mechanical properties. Adaptation is difficult. For example, polylactic acid has a glass transition temperature (Tg: a temperature at which the storage elastic modulus decreases to about 1/10 to about 1/100 at room temperature) is around 60 ° C. From about 1 × 10 ⁹ Pa to about 1 × 10 ⁷ Pa. Therefore, mechanical deformation is likely to occur.

The present invention has been made in view of the above problems, and has as its object to provide a biodegradable resin composition having an improved elastic modulus, a housing material comprising the biodegradable resin composition, and a biodegradable resin composition. An object of the present invention is to provide a method for producing a resin composition and a method for improving the elastic modulus of the biodegradable resin composition.

[0013]

The biodegradable resin composition of the present invention comprises at least an aliphatic polyester resin, an organic nucleating agent, and natural mica. 1). As the organic nucleating agent, it is desirable to select and mix one or more of aliphatic carboxylic acid amides and aliphatic carboxylic acid esters (claim 2). The mixing amount of natural mica with respect to the aliphatic polyester resin is preferably in the range of 5.0 to 20.0% by weight (Claim 3). The compounding amount of the organic nucleating agent with respect to the aliphatic polyester resin is preferably in the range of 0.5 to 5.0% by weight (Claim 4). Preferred specific examples of the aliphatic polyester resin include polylactic acid (claim 5).

In general, housings and structural materials of electrical products manufactured by directly molding a biodegradable resin by injection molding or the like have low mechanical strength. It has been difficult to manufacture a housing or the like having the shape and structure described above with good yield. Further, even if no deformation occurs at the time of machining, there is a drawback that deformation is likely to occur when stored at a high temperature or when used at a high temperature.

On the other hand, in the biodegradable resin composition of the present invention, an organic nucleating agent and natural mica are blended as a reinforcing component with the biodegradable resin. Strength (elastic modulus) is improved. As a result, the dimensional and shape stability during high-temperature storage is improved, and the casing and structural material made of this biodegradable resin material are less likely to change in warp and dimensions at high temperatures.

The biodegradable resin composition of the present invention comprises an aliphatic polyester resin, an organic nucleating agent, natural mica,
An additive which suppresses hydrolysis of the aliphatic polyester resin is contained (claim 6). The additive for suppressing the hydrolysis is preferably a carbodiimide compound (claim 7). The amount of the hydrolysis inhibiting additive is 0.1% based on the amount of the aliphatic polyester resin.
The preferred range is 1 to 2.0% by weight (claim 8).

Further, the housing material of the present invention is characterized by comprising a biodegradable resin composition containing at least an aliphatic polyester resin, an organic nucleating agent and natural mica. ). As the biodegradable resin composition in this case, the composition according to any one of claims 2 to 8 can be employed.

Further, the method for producing a biodegradable resin composition according to the present invention comprises the steps of: providing an aliphatic polyester resin; 5.0 to 20.0% by weight of natural mica with respect to the aliphatic polyester resin; An organic nucleating agent is kneaded at 150 to 200 ° C. (claim 10).

Further, the method for improving the elastic modulus of a biodegradable resin composition according to the present invention is characterized in that the biodegradable resin composition contains at least an aliphatic polyester resin, an organic nucleating agent and natural mica. The product is heated at 80 to 130 ° C. for 30 minutes.
For at least 180 seconds.
1). As the biodegradable resin composition in this case, the composition according to any one of claims 2 to 8 can be employed.

Further, the method for improving the modulus of elasticity of a biodegradable resin composition according to the present invention is characterized in that a biodegradable resin composition containing at least an aliphatic polyester resin, an organic nucleating agent and natural mica is treated with gold. Injection (for example, using an extruder) into a mold to form an injection molded product, and then heating the injection molded product in the mold at 80 to 130 ° C. for 30 to 180 seconds (claim) Item 12). As the biodegradable resin composition in this case, the composition according to any one of claims 2 to 8 can be employed.

Further, the method for improving the modulus of elasticity of a biodegradable resin composition according to the present invention comprises the step of using a biodegradable resin composition containing at least an aliphatic polyester resin, an organic nucleating agent and natural mica. The injection molding is performed by injecting the inner surface into a mold whose inner surface is heated by high-frequency induction heating, and then the injection molding in the mold is heated at 80 to 130 ° C. for 30 to 180 seconds. (Claim 13). As the biodegradable resin composition in this case, the composition according to any one of claims 2 to 8 can be employed.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. The biodegradable resin composition according to the present invention is mainly composed of an aliphatic polyester resin having excellent moldability, heat resistance and impact resistance among polyesters metabolized by microorganisms. In addition, as the natural mica, granulated mica obtained by granulating using an acrylic resin, an epoxy resin or a urethane resin as a binder is usually used.

As the aliphatic polyester resin,
Polylactic acid-based aliphatic polyester resin, specifically, lactic acid, malic acid, polymers of oxyacids such as glucose acid or copolymers thereof, especially hydroxycarboxylic acid-based aliphatic polyester resin represented by polylactic acid Can be mentioned.

The above-mentioned polylactic acid-based aliphatic polyester resin is usually produced by a method based on ring-opening polymerization of a cyclic diester lactide and the corresponding lactone, a so-called lactide method. Each can be obtained.

The catalyst for producing the polylactic acid-based aliphatic polyester resin includes tin, antimony,
Examples thereof include zinc, titanium, iron and aluminum compounds. Among them, tin catalysts and aluminum catalysts are preferable, and tin octylate and aluminum acetyl acetate are particularly preferable.

Among the above-mentioned polylactic acid-based aliphatic polyester resins, the polylactic acid-based aliphatic polyester resin obtained by lactide ring-opening polymerization is hydrolyzed by a microorganism into poly-L-lactic acid to form L-lactic acid. This L-form-lactic acid is preferable because it has been confirmed that it is safe for the human body and the like. However, the polylactic acid-based aliphatic polyester resin according to the present invention is not limited to this, and therefore, the lactide used for producing the same is not limited to the L-form.

On the other hand, nucleating agents used in the present invention include:
It has a melting point or softening point of 80-300 ° C and about 4
Organic compounds having a melting entropy of 1.84 to 418.4 J / k / mol, and specific examples thereof include aliphatic carboxylic acid amides, aliphatic carboxylic acid esters, aliphatic carboxylic acids, and aliphatic alcohols. And aliphatic carboxylic acid amides are particularly preferred.

The above-mentioned aliphatic carboxylic acid amide has a melting point or a softening point in the range of 80 to 300 ° C. and a melting entropy of about 41.84 to 418.4 J / k / mo.
There is no particular limitation as long as it is within the range of l. The aliphatic carboxylic acid amides include aliphatic amides (“10899 Chemical Products (1989, Chemical Daily Inc., p. 389)).

The aliphatic carboxylic acid amide is
It is a compound containing at least one structure in which nitrogen is bonded to carbonyl carbon. Specifically, it includes a bond usually called an amide bond, and also includes a bond usually called a urea bond. A hydrogen atom or an aliphatic group is bonded to the carbonyl carbon and the nitrogen atom bonded thereto.
Specifically, the aliphatic group to be bonded has not only an aliphatic group in a narrow sense, but also an aromatic group, a group obtained by combining them, or a structure in which these are bonded by oxygen, nitrogen, sulfur, silicon, phosphorus, or the like. It also includes a group consisting of residues, and more specifically, those described above include, for example, a hydroxyl group, an alkyl group, a cycloalkyl group, an allyl group, an alkoxyl group, a cycloalkoxyl group, an allyloxyl group, a halogen (F, Cl, B
(r etc.) also includes a group consisting of residues having a structure in which a group or the like is substituted. By appropriately selecting these substituents, the effect as a nucleating agent can be adjusted, whereby the biodegradable resin comprising an aliphatic polyester resin such as a lactic acid-based polymer according to the present invention. Various properties (heat resistance, mechanical strength, etc.) of the composition can be adjusted.

Specific examples of the aliphatic carboxylic acid amide include, for example, lauric amide, palmitic amide, stearic amide, erucic amide, behenic amide, N-stearylstearic amide, methylol stearic amide, and methylol behamide. Nitric acid amide, dimetol oil amide, dimethyl lauric amide, dimethyl stearic acid amide and the like can be mentioned. In addition, ethylene bisoleic acid amide, ethylene bis stearic acid amide, ethylene bis lauric acid amide, hexamethylene bis oleic acid amide, butylene bis stearic acid amide, m-xylylene bis stearic acid amide, m-xylylene bis-12-hydroxy stearin Acid amide,
N, N'-dioleyl adipamide, N, N'-distearyl adipamide, N, N'-distearyl isophthalamide, N, N'-distearyl terephthalamide, N-butyl-N ' Examples include stearyl urea, N-propyl-N 'stearyl urea, N-allyl-N' stearyl urea, N-stearyl-N 'stearyl urea and the like.

Among the above, ethylene bisstearic acid amide, palmitic acid amide, stearic acid amide, erucic acid amide, behenic acid amide, ethylene bisoleic acid amide, ethylene bislauric acid amide, N-stearyl stearic acid amide, m -Xylylenebisstearic acid amide and m-xylylenebis-12-hydroxystearic acid amide are particularly preferred.

The additives used in the present invention for suppressing the hydrolysis of the above-mentioned biodegradable aliphatic polyester resin include those having reactivity with carboxylic acid and hydroxyl group which are terminal functional groups of the polyester resin. Compounds having, for example, carbodiimide compounds, isocyanate compounds, oxozoline compounds and the like can be applied, in particular, carbodiimide compounds can be melt-kneaded well with polyester,
It is suitable because hydrolysis can be suppressed by adding a small amount.

As a carbodiimide compound having one or more carbodiimide groups in a molecule (including a polycarbodiimide compound), for example, an organic phosphorus compound or an organic metal compound is used as a catalyst, and various polymer isocyanates at about 70 ° C. or higher are used. Those which can be synthesized by subjecting to a decarboxylation condensation reaction in a solvent-free or inert solvent at a temperature.

Examples of the monocarbodiimide compound contained in the carbodiimide compound include dicyclohexylcarbodiimide, diisopropylcarbodiimide, dimethylcarbodiimide, diisobutylcarbodiimide, dioctylcarbodiimide, diphenylcarbodiimide, naphthylcarbodiimide and the like. From the point of easy availability,
Dicyclohexylcarbodiimide or diisopropylcarbodiimide is preferred.

The mixing (blending) of the carbodiimide compound with the biodegradable plastic can be performed by melt-kneading using an extruder. In addition, since the biodegradation rate of the biodegradable plastic of the present invention can be adjusted by the type and the amount of the carbodiimide compound to be compounded, the type and the amount of the carbodiimide compound to be compounded according to the target product. Should be determined.

[0036]

Next, examples of the present invention and comparative examples will be described. FIG. 1 and FIG. 2 show a biodegradable resin composition (Example) obtained by blending a nucleating agent, natural mica and an additive for inhibiting hydrolysis with polylactic acid containing no special additive. 4 is a graph showing the relationship between temperature and storage modulus for polylactic acid not used (Comparative Example).

First, the storage modulus and the glass transition temperature T
The method for measuring g will be described. Measuring device: Rheometric viscoelastic analyzer Sample piece: length 50 mm × width 7 mm × thickness 1 mm Frequency: 6.28 (rad / s) Measurement start temperature: 0 ° C. Measurement end temperature: 160 ° C. Heating rate: 5 ° C / min Strain: 0.05%

Comparative Example 1 In a sample piece of polylactic acid, Laissia H100J (manufactured by Mitsui Chemicals, Inc.), as shown in FIG. 1, the storage elastic modulus E ′ rapidly dropped from around the glass transition temperature Tg (60 ° C.). 1
It showed a minimum value at around 00 ° C., after which the storage modulus rapidly increased and showed a substantially constant value in the range from around 120 ° C. to 140 ° C. The storage modulus at a temperature of 70 ° C to 140 ° C was 1 × 10 ⁸ or less.

Example 1 10% by weight of granulated mica powder 41PU5 (containing 0.8% by weight of a urethane resin binder: manufactured by Yamaguchi Mica Industries Co., Ltd.) obtained by granulating natural mica having a particle size of 40 to 50 μm into Lacea H100J. Carbodilite H as an additive for inhibiting hydrolysis
1% by weight of MV-10B (manufactured by Nisshinbo) and 1% by weight of ethylene bisstearic acid amide (aliphatic carboxylic acid amide) as an organic nucleating agent were mixed and uniaxially kneaded at a set temperature of 180 ° C. The composition melt-blended by the machine was pelletized, and a plate material having a thickness of 1 mm was produced by a hot press machine at a set temperature of 170 ° C. And the storage elastic modulus of the sample piece cut out from this plate material was measured. In the sample of Example 1, as shown in FIG. 1, unlike in Comparative Example 1, a sharp decrease in the storage modulus from around Tg (60 ° C.) was not observed, and the storage at a temperature of 70 ° C. to 140 ° C. The elastic modulus is greatly improved, and especially at about 100 ° C. to about 120 ° C., about 1 ×
It was 10 ^9.

Example 2 The sample piece of Example 1 was aged at 120 ° C. for 60 seconds. As a result, as shown in FIG.
The storage elastic modulus of Example 1 was significantly improved as compared with Example 1.

Example 3 The above granulated mica powder 41PU5 was added to Laecia H100J in 1
0% by weight, 1% by weight of carbodilite HMV-10B as an additive for inhibiting hydrolysis, and 1% by weight of erucamide (aliphatic carboxylic acid amide) as an organic nucleating agent. A sample piece was prepared in the same manner as in Example 1, and the storage modulus was measured. In the sample of Example 3, as shown in FIG. 2, the storage elastic modulus was significantly improved as compared with Comparative Example 1.

Example 4 The sample piece of Example 3 was aged at 120 ° C. for 60 seconds. As a result, as shown in FIG.
The storage modulus at 0 ° C. was further improved as compared with Example 3.

Example 5 The above granulated mica powder 41PU5 was added to Laecia H100J in 1
0% by weight, 1% by weight of carbodilite HMV-10B as an additive for inhibiting hydrolysis, and 1% by weight of tributyl acetylcitrate (aliphatic carboxylate) as an organic nucleating agent. A sample piece was prepared in the same manner as in Example 1, and this was aged at 120 ° C. for 60 seconds. As a result, the storage modulus was significantly improved as compared with Comparative Example 1 (not shown).

Example 6 The above granulated mica powder 41PU5 was added to Lacia H100J in an amount of 1
0% by weight, 1% by weight of carbodilite HMV-10B as an additive for inhibiting hydrolysis, and 1% by weight of diisodecyl adipate (aliphatic carboxylate) as an organic nucleating agent. A sample piece was prepared in the same manner as in Example 1, and was aged at 120 ° C. for 60 seconds. As a result, the storage modulus was significantly improved as compared with Comparative Example 1 (not shown).

Example 7 Using the pellets obtained in Example 1, the pellets having a resin temperature of 180 ° C. were poured into a mold in which the vicinity of the mold surface was rapidly heated to 120 ° C. by high-frequency induction heating using a coil. Mold and cool slowly. By applying a high temperature of 120 ° C., aging occurred during injection molding, and an improvement in the elastic modulus was observed (not shown).

[0046]

The biodegradable resin composition according to claim 1 is
It is a mixture of an aliphatic polyester resin with an organic nucleating agent and natural mica. Therefore, the biodegradable resin composition of the present invention has improved mechanical strength, is less likely to be deformed or warped during machining, and has improved dimensional stability. For this reason, according to the biodegradable resin composition of the present invention, it is possible to provide a material having sufficient mechanical strength for manufacturing a housing for home electric appliances, electronic devices, and the like. In other words, since the biodegradable resin is an aliphatic polyester resin, it can be widely used in housings for home electric appliances and electronic devices, as well as materials for agriculture, forestry and fisheries, civil engineering materials, packaging and containers, and the like. .

In the biodegradable resin composition according to claim 2,
Since one or more selected from aliphatic carboxylic acid amides and aliphatic carboxylic acid esters are blended as the organic nucleating agent, the elastic modulus is further improved and the mechanical strength is also enhanced.

[0048] In the biodegradable resin composition according to claim 3,
Since the compounding amount of natural mica with respect to the aliphatic polyester resin is in the range of 5.0 to 20.0% by weight, a significant effect of improving the elastic modulus can be obtained. If the amount is less than 5.0% by weight, the effect of improving the elastic modulus becomes insufficient. If the amount is more than 20.0% by weight, the effect of improving the elastic modulus will level off, and it will be difficult to uniformly knead and mix natural mica. In addition, the surface of the pellet obtained from the kneaded material becomes rough, and a molded product from the pellet becomes inferior in surface smoothness.

In the biodegradable resin composition according to claim 4,
Since the compounding amount of the organic nucleating agent with respect to the aliphatic polyester resin is set to 0.5 to 5.0% by weight, the effect of greatly improving the elastic modulus can be obtained. If the amount is less than 0.5% by weight, the effect of improving the elastic modulus becomes insufficient. 5.0% by weight
When the ratio exceeds the above, the effect of improving the elastic modulus reaches a plateau, and the compatibility of the additive with the aliphatic polyester resin is reduced. As a result, the nucleating agent exudes to the surface of the biodegradable resin composition over time. Failure occurs.

In the biodegradable resin composition according to claim 5,
Since polylactic acid is used as the aliphatic polyester resin, there is an advantage that the safety of the hydrolysis product from this biodegradable resin composition is particularly high.

The biodegradable resin composition according to claim 6 comprises an aliphatic polyester resin, an organic nucleating agent, natural mica, and an additive for suppressing the hydrolysis of the aliphatic polyester resin. It contains. For this reason, it is possible to meet various demands by determining the type and amount of the above-mentioned hydrolysis-suppressing additive according to the use and characteristics of the molded article (product) using the biodegradable resin composition as a material. A molding material comprising the biodegradable resin composition thus obtained can be provided. Also, by adding an appropriate amount of the above-mentioned hydrolysis-suppressing additive, the elastic modulus at a high temperature, particularly at a temperature higher than the glass transition temperature of the biodegradable resin, is increased.

In the biodegradable resin composition according to claim 7,
As an additive for suppressing hydrolysis, a carbodiimide compound having a remarkable effect when added in a small amount is blended.
Therefore, by determining the type and the amount of the carbodiimid compound according to the use and characteristics of the molded article (product) using the biodegradable resin composition as a material, the biodegradability corresponding to various demands is determined. A molding material composed of a resin composition can be provided.

In the biodegradable resin composition according to claim 8,
The amount of the additive that suppresses the hydrolysis of the biodegradable resin is 0.1 to 2.0% by weight based on the amount of the aliphatic polyester resin. For this reason, the effect of improving the elastic modulus at a high temperature is particularly enhanced, and the chemical stability, for example, weather resistance, light resistance, and heat resistance are improved. Further, in this range, the compatibility between the biodegradable resin and the additive is improved, and the mixing state is stabilized. When the amount is less than 0.1% by weight, the effect of the additive becomes insufficient. When the amount exceeds 2.0% by weight, the effect of hydrolysis resistance does not increase.

The housing material according to the ninth aspect is made of the biodegradable resin composition of the first aspect, and thus can be used as a material for producing a housing for home electric appliances and electronic devices having sufficient mechanical strength. It is. Further, in the case made of the case material using the biodegradable resin composition according to the present invention, there are many choices of a disposal method at the time of disposal, and even if it is disposed as it is, it does not remain as long-term garbage and impairs the scenery. Nor. Further, the material may be recycled like a normal resin. further,
Since the biodegradable resin composition of the present invention does not contain harmful substances such as heavy metals and organochlorine compounds, there is no risk of generating harmful substances even when discarded or incinerated. Further, when the biodegradable resin is made from cereal resources, there is an advantage that it is not necessary to use depleted resources such as petroleum.

The method for producing a biodegradable resin composition according to claim 10 is characterized in that the aliphatic polyester resin, 5.0 to 20.0% by weight of natural mica with respect to the aliphatic polyester resin, And a system nucleating agent is kneaded at 150 to 200 ° C. Therefore, according to this production method, natural mica and the polyester resin can be uniformly kneaded, and a biodegradable resin composition having uniform properties and a significantly improved elastic modulus can be easily and easily kneaded. -It can be easily obtained by the process. By molding this biodegradable resin material by injection molding, etc., it is possible to stably produce molded products (injection molded products, extrusion molded products, etc.) with excellent characteristics. it can. If the kneading temperature is lower than 150 ° C., kneading becomes insufficient, and if the kneading temperature exceeds 200 ° C., the biodegradable resin tends to be thermally decomposed.

In the method for improving the elastic modulus of a biodegradable resin material according to claim 11, the biodegradable resin composition of claim 1 is
Since it is left (aged) for 30 to 180 seconds under the heating of up to 130 ° C., the effect of improving the elastic modulus is further enhanced as compared with the case where it is not aged.

In the method for improving the elastic modulus of a biodegradable resin material according to claim 12, the biodegradable resin composition of claim 1 is injected into a mold to form an injection molded product, and then the injection molding in the mold. The article is heated at 80 to 130 ° C. for 30 to 180 seconds, and in the method for improving elastic modulus according to claim 13,
The biodegradable resin composition of claim 1 is injected into a mold whose inner surface is heated by high-frequency induction heating to form an injection molded product, and then the injection molded product in the mold is heated to 80 to 130 ° C.
Then, since the heating is performed for 30 to 180 seconds, the method for improving the elastic modulus according to claim 11 can be implemented by a simple process.

[Brief description of the drawings]

FIG. 1 is a biodegradable resin composition according to Examples and Comparative Examples of the present invention, which is obtained by mixing an organic nucleating agent, an additive for inhibiting the hydrolysis of natural mica and polylactic acid with polylactic acid. 5 is a graph showing the relationship between temperature and storage elastic modulus of (Examples 1 and 2) and polylactic acid not containing this (Comparative Example 1).

FIG. 2 relates to Examples and Comparative Examples of the present invention, and is a biodegradable resin composition obtained by blending polylactic acid with an organic nucleating agent, an additive for suppressing the hydrolysis of natural mica and polylactic acid. 4 is a graph showing the relationship between temperature and storage elastic modulus of (Examples 3 and 4) and polylactic acid not containing this (Comparative Example 1).

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08K 3/34 C08K 3/34 5/10 5/10 5/20 5/20 5/29 5/29 / / B29K 67:00 ZBP B29K 67:00 ZBP 509: 10 509: 10 (72) Inventor Hiroyuki Mori 6-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo F-term in Sony Corporation (reference) 4F201 AA24 AB08 AB17 AB19 AK11 AR06 BA01 BA02 BA04 BA07 BC01 BC19 BC37 BD04 BK02 BK13 BK25 BL29 BL43 BN01 BR01 BR12 BR34 4F206 AA24 AB08 AB17 AB19 AK11 AR06 JA02 JB02 JE06 JN43 JW08 4J002 CF031 CF181 CF191 DJ057 EC036 EF0206 EF0206 EF0206 EF0208

Claims (13)

[Claims] 1. A biodegradable resin composition comprising at least an aliphatic polyester resin, an organic nucleating agent and natural mica. 2. The biodegradable resin composition according to claim 1, wherein the organic nucleating agent is one or more selected from aliphatic carboxylic acid amides and aliphatic carboxylic acid esters. 3. The biodegradable resin composition according to claim 1, wherein the blending amount of the natural mica with respect to the aliphatic polyester resin is 5.0 to 20.0% by weight. 4. The biodegradable resin composition according to claim 1, wherein the blending amount of the organic nucleating agent with respect to the aliphatic polyester resin is 0.5 to 5.0% by weight. 5. The biodegradable resin composition according to claim 1, wherein the aliphatic polyester resin is polylactic acid. 6. The biodegradable resin composition according to claim 1, further comprising an additive that inhibits hydrolysis. 7. The biodegradable resin composition according to claim 6, wherein the additive that inhibits hydrolysis is a carbodiimide compound. 8. The biodegradable resin composition according to claim 6, wherein the amount of the additive that inhibits hydrolysis is 0.1 to 2.0% by weight based on the amount of the aliphatic polyester resin. 9. A housing material comprising a biodegradable resin composition containing at least an aliphatic polyester resin, an organic nucleating agent, and natural mica. 10. An aliphatic polyester resin, and 5.0 to 20.0% by weight based on the aliphatic polyester resin.
Of natural mica and organic nucleating agent at 150 to 200 ° C
A method for producing a biodegradable resin composition, which comprises kneading the composition. 11. A method of leaving a biodegradable resin composition containing at least an aliphatic polyester resin, an organic nucleating agent and natural mica at a temperature of 80 to 130 ° C. for 30 to 180 seconds. A method for improving the elastic modulus of a biodegradable resin composition. 12. A biodegradable resin composition containing at least an aliphatic polyester resin, an organic nucleating agent, and natural mica, is injected into a mold to form an injection molded product, and then the injection molding is performed. The injection molded product is heated at 80 to 130 ° C. for 30 to 1
A method for improving the elastic modulus of a biodegradable resin composition, comprising heating for 80 seconds. 13. A biodegradable resin composition containing at least an aliphatic polyester resin, an organic nucleating agent and natural mica is injected into a mold whose inner surface is heated by high frequency induction heating. A method for improving the elastic modulus of the biodegradable resin composition, wherein the injection molded article in the mold is heated at 80 to 130 ° C. for 30 to 180 seconds.