JP2001098105A - Method for manufacturing expanded product having biodegradability - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for molding, capable of transporting expandable particles made of polylactic acid composition having biodegradability to post processors in the state as it is and to improve foaming in post processing and flexibility and cushioning characteristics of post processing products thereof. SOLUTION: This method comprises molding expanded products mainly containing polylactic acid of L-isomer and D-isomer at a ratio (95:5) to (60:40) and is characterized by previously providing expanded particles mainly comprising polylactic acid, compounding a biodegradable resin having <=40 deg.C glass transition point to the expanded particles and molding the resultant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a biodegradable composition,
An object of the present invention is to provide a method for producing a foamed molded product mainly used as a packaging material by using lactic acid that contributes to global environmental protection as a raw material.

[0002]

2. Description of the Related Art Plastic foams utilizing light weight, cushioning properties, and moldability are widely used as packaging and packing materials, and are made of petroleum-based chemical products such as polystyrene (PS) and polyolefin. It is difficult to dispose after use, and even if it is incinerated, it has a high calorie burn,
It has become a major social problem that it does not decompose even if it is damaged by incinerators or landfilled, and because it has a large volume, it occupies the space of the disposal site.

[0003] In addition, the effects of natural foams, such as rivers and oceans, caused by foams discarded without being disposed of are no longer ignored. Therefore, resins that decompose in the ecosystem and have less impact on the global environment have been developed. For example, a polyhydroxybutyrate resin synthesized in the body of a microorganism, a polyester composed of an aliphatic glycol and an aliphatic carboxylic acid, or a polyester resin containing caprolactone as a main component, etc., have been announced. Due to the production of microorganisms, the purity is low, the productivity is extremely low, and the use is limited.

The latter is certainly good in productivity because the raw material is inexpensive and available in large quantities such as petroleum and natural gas. However, since it is a crystalline resin and has a low glass transition point, it is biodegradable. The practical use of packaging materials is limited in terms of practicality, and petroleum and natural gas are used as raw materials.When decomposed, carbon dioxide is added to the existing carbon dioxide on the earth, so it is necessary to control the increase in carbon dioxide. Does not contribute. In the long term, since the raw material source is limited, it becomes difficult to obtain the material source soon, and it cannot contribute to global environmental protection in the true sense.

Further, as a biodegradable material, glycolic acid, lactic acid and the like can be obtained as a polymer by ring-opening polymerization of glycolide or lactide, and are used as a sustained-release agent for medical use or as a fiber for medical use. However, as it is, it has not been used in a large amount as a foam, as a packaging container or as a cushioning material.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide expandable particles obtained from a biodegradable polylactic acid composition to a downstream processor in the form of expandable particles in the same manner as polystyrene expandable particles. The object of the present invention is to improve the flexibility and cushioning of a molded product obtained by conveying and processing and foaming and molding.

[0007] Regarding the expandable particles and expanded particles of the polylactic acid composition, Japanese Patent Laid-Open Nos. 5-17965 and 5-1 have already been disclosed.
7966. However, as a result of a detailed examination by the present inventors, none of the proposals was expected to be effective. JP-A-5-17965 proposes foamed particles. However, even if the method detailed in the specification is faithfully reproduced, it is not possible to stably produce high-expanded foamed particles in large quantities. I could not do it. The cause is that when the polylactic acid composition treated in a water dispersion system under high temperature and high pressure is spouted into the atmosphere at high temperature, it becomes flocculent and does not become particles.

[0008] In order to pre-expand expandable beads such as expandable polystyrene beads and form the expanded particles into a form, spherical particles close to a true sphere are required. It is. In addition, the treated polylactic acid composition was
When it is cooled to around 0 ° C. and jetted, only deformed expanded particles having a low expansion ratio can be obtained, which is not endurable for forming. Furthermore, JP-A-5-17965 does not disclose any other production method, and it cannot be expected that foamed particles can be obtained by this proposal. On the other hand, JP-A-5-17966
The expandable particles proposed in the specification is described in the specification that it is manufactured by a method far from the generally adopted method is not realistic, and if the expandable particles are obtained from the expandable particles manufactured by this proposal, However, it is difficult to stably produce expanded particles having a high expansion ratio.

The present inventors have proposed a base polymer which is an essential condition as a biodegradable resin having a high foaming property.
As a result of detailed studies on an additive for increasing the molecular weight, an additive for foaming, and the like, a biodegradable resin composition having practically sufficient productivity was found, and an invention was proposed. The expandable particles obtained by impregnating the biodegradable resin composition with a foaming agent can be transported to a subsequent processor in the form of expandable particles, like the polystyrene expandable particles. However, although the foamed particles obtained by the proposal have a high expansion ratio, molded articles obtained from the foamed particles have insufficient flexibility and their applications are limited.

[0010] Japanese Patent Application Laid-Open No. 8-253617 proposes improvement of flexibility by using a copolymer of polylactic acid.
Even if foamable particles are obtained according to the proposal, the volatilization of the foaming agent is fast because the copolymer is a copolymer, and it is difficult to transport the foamable particles in the state of the present invention to a post-processing company. According to the proposal, flexible foamed particles can be produced, but the distribution of goods must be carried out by the foamed particles or a molded product thereof, which is extremely uneconomical. Also, because it is copolymerized polylactic acid,
It also has the disadvantage that the glass transition point is reduced and the deformation under load is large.

[0011]

Means for Solving the Problems The present inventors have determined that it is essential to overcome such problems in order to produce and use in large quantities, and as a result of earnest research, have arrived at the present invention. That is, according to the present invention, the weight ratio of L-form to D-form is 95/5.
When producing a foamed product mainly composed of polylactic acid in the range of 60 to 40/40, foamed particles mainly composed of polylactic acid are produced in advance, and biodegradation in which the glass transition point of the foamed particles is 40 ° C. or lower is performed. This is a method for producing a biodegradable foamed molded product, which is characterized by performing a molding process after blending a reactive resin.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A process for producing a molded article comprising expanded particles mainly composed of polylactic acid is generally as follows. First, polylactic acid is polymerized. A polylactic acid composition is prepared by adding a thickener and a foam nucleating agent thereto. Next, the polylactic acid composition is impregnated with a foaming agent and a foaming aid to form foamable particles. Further, the expandable particles are heat-treated to obtain expanded particles. Finally, foamed particles are formed. Hereinafter, the present invention will be described along the manufacturing steps.

When the weight ratio between the L-form and the D-form used in the present invention is 9
The polylactic acid in the range of 5/5 to 60/40 includes polylactic acid having a melting point but a small heat of fusion. That is, the heat of fusion (2nd sc
an @ H) is a polylactic acid of 0.1 J / g or less, corresponding to a D-form copolymerization ratio of 5 mol% or more. This is macr
omolecules 255719-5729 (199
2) It is close to X _D = 0.048 or more described. The D-form and the L-form of the polylactic acid used in the present invention must have a copolymerization ratio of 5 to 40 mol% for the D-form.
~ 20 mol% is preferably used. In particular, when expanded particles having a high expansion ratio are required, the heat of fusion (2nd sca) is required.
The D-form without n △ H) is preferably 8 to 20 mol%. If the molar ratio of the D-form is less than this range, the crystallinity is high, and the expansion ratio does not increase, or the foaming becomes nonuniform, so that it cannot be used. On the other hand, when the amount of D-form exceeds this range, heat resistance is inferior and cannot be used.

The polylactic acid used in the present invention is preferably a high molecular weight polylactic acid having a melt viscosity in the range of 1 to 10 by a melt index value (MI) according to JIS K7210 (load: 2.16 kgf). However, even if the polylactic acid is used as it is, expanded particles having a high expansion ratio cannot be obtained. In order to obtain expanded particles having a high expansion ratio, it is necessary to obtain a polylactic acid composition which has been further made to have a very high viscosity by reacting with a viscosity increasing agent such as a polyisocyanate, an acid anhydride or an epoxy compound. For example, in order to obtain expanded particles having a high expansion ratio of 10 times or more, it is desirable that the composition has a melt viscosity (MI) of 5 or less, preferably 1 or less. When the MI value is in this range, it is preferable because a foam having excellent productivity and a high expansion ratio can be obtained.

The polyisocyanate used in the present invention may be any of aromatic, alicyclic and aliphatic polyisocyanates. For example, aromatic polyisocyanates include tolylene, diphenylmethane, naphthylene, tolidine and xylene. There is a polyisocyanate having a triphenylmethane skeleton, a polyisocyanate having a hydrogenated diphenylmethane skeleton as an alicyclic polyisocyanate, and a polyisocyanate having a hexamethylene skeleton as an aliphatic polyisocyanate. Tolylene, diphenylmethane, especially diphenylmethane is preferably used from the viewpoints of handleability, weather resistance and the like.

In the polylactic acid used in the present invention, an inorganic powder such as talc, kaolin, mica, bentonite, or zeolite is used for the purpose of improving the expansion ratio, uniformity of the foam cells, and miniaturization of the foam cells. Is done. Among them, talc is most preferable, and 0.5 to 20% by weight, more preferably 2 to 10% by weight based on the polylactic acid. When the amount of talc is in this range, the flexibility of the obtained molded article is improved, and the talc has an excellent function as a packaging material, which is preferable.

The talc used in the present invention has an average particle diameter of preferably 10 μm or less, more preferably 5 μm or less, particularly preferably 3 μm or less. In many cases, the thickness of the foam cell membrane is several μm.

The method of adding and dispersing the thickener and / or talc to the polylactic acid used in the present invention is a polymerization step of obtaining polylactic acid from lactide, and melting the polylactic acid and the thickener and / or talc with a kneader or the like. Any method of kneading may be used,
In order to add and disperse talc at a high concentration, a method of melt-kneading using a twin-screw kneader is preferable.

The polylactic acid resin composition thus obtained contains
When a foaming agent and a foaming aid are impregnated and subjected to a foaming treatment, a foam having a high expansion ratio is obtained. As the foaming agent used here, hydrocarbons such as propane, n-butane, isobutane, n-pentane, isopentane, cyclopentane and hexane, and ethers such as dimethyl ether and methyl ethyl ether are used. In the case of polylactic acid, carbon number 3-4
It is preferable to use the hydrocarbon of the above. Alcohols having 1 to 4 carbon atoms, ketones, ethers and the like are mainly used as foaming assistants.

The impregnation of a foaming agent and a foaming aid can be carried out by a usual method, and can be carried out under heating and under high pressure in an aqueous dispersion or non-aqueous system. For example, a predetermined amount of the polylactic acid of the present invention, a foaming agent, and a foaming assistant are charged into an autoclave, and the internal temperature is 80 to 9;
By heating for several hours while maintaining the temperature at 0 ° C., expandable particles can be easily obtained.

By heating the obtained expandable particles under appropriate conditions with steam, expanded particles having a high expansion ratio can be easily produced. As appropriate conditions for foaming,
From the viewpoint of the expansion ratio and the secondary expandability of the expanded particles, the temperature of steam is preferably 50 to 105 ° C., and the heating time is preferably 10 to 300 seconds.

In the present invention, it is preferable to use an anti-blocking agent when obtaining expanded particles from expandable particles. As the antiblocking agent, metal salts of higher fatty acids, particularly magnesium stearate and zinc stearate are preferably used. Its preferred amount is
It is in the range of 0.01 to 0.1% by weight based on the expandable particles.

The molded article obtained by molding the thus obtained expanded particles of the present invention simply by using a conventional foam molding machine is inferior in flexibility to an expanded polystyrene molded article having the same density. Even if the molding conditions such as steam pressure, time, and cracking are variously changed, it is impossible to improve flexibility.

Therefore, in the present invention, a molding process is performed after a biodegradable resin having a glass transition point of 40 ° C. or less is added to the foamed particles during molding. Thereby, the obtained molded product is greatly improved in flexibility, which is equivalent to that of the expanded polystyrene molded product.

The glass transition point of the biodegradable resin of 40 ° C. or lower is a glass transition point in a dry state. or,
The biodegradable resin needs to be a resin having a crystal part. The reason is that amorphous biodegradable polyester resin or biodegradable polyurethane resin obtained from aliphatic dicarboxylic acid and aliphatic glycol and / or hydroxy carboxylic acid cannot be used because of poor solvent resistance, heat resistance and the like. . Even if a resin having a glass transition point exceeding 40 ° C. is added, the flexibility of the molded product is not improved.

The biodegradable resin having a glass transition point of 40 ° C. or lower used in the present invention includes malonic acid, succinic acid, adipic acid and sebacic acid as aliphatic dicarboxylic acids and ethylene glycol propylene as aliphatic glycol. There are glycol, butylene glycol, hexanediol and the like, and a resin having a glass transition point of 40 ° C. or lower is selected from resins of these combinations. Among these, a resin mainly composed of polybutylene succinate is preferably used. In addition, polycaprolactone is preferred as the resin from hydroxycarboxylic acid or lactone.
Further, as the biodegradable polyurethane resin, a resin composed of polybutylene adipate as a soft segment, diphenylmethane diisocyanate as a hard segment, and a resin composed of butanediol as a chain extender is preferably used.

The compounding amount of the biodegradable resin with respect to the expanded particles is 1 to 50% by weight, preferably 3 to 20% by weight.
When the compounding amount is in this range, a molded article having a high expansion ratio and excellent flexibility is obtained, which is preferable.

The method of blending the biodegradable resin with the foamed particles may be any of pellets, powders, and mixing with a solution. Among them, powder mixing is preferably used from the viewpoint of reduction in the amount used and simplicity. Is done. The smaller the particle diameter of the powder is, the better, but 1 mm or less, and further preferably 0.2 mm or less is preferable from the viewpoint of the adsorptivity to the surface of the foamed particles.

In the present invention, other additives can be appropriately added to the foamed particles according to the purpose. Examples of the additives include a heat stabilizer, an antioxidant, a flame retardant, an ultraviolet absorber, and a plasticizer. is there. However, the flame retardant or the like is often a halide such as chlorine, and is preferably minimized from the viewpoint of biodegradability and generation of harmful substances during incineration.

The molded product obtained by the present invention can be used for various applications by utilizing its excellent flexibility and cushioning property, and has a very high economic value.

[0031]

The present invention will be described more specifically with reference to the following examples and comparative examples. In addition, evaluation was performed by the following method.

ΔH: DSC7 manufactured by PerkinElmer was used. After the first scan of 10 mg of the sample heated to 200 ° C. at 10 ° C./min, it was quenched and brought to 0 ° C., and the second scan heated to 200 ° C. at 10 ° C./min.
Measured with n. The melting point and glass transition point were measured in the same manner.

Polylactic acid MI: Measured by a method according to JIS K7210. (Measurement temperature 190 ° C, orifice diameter 2mm, 2.16kg load condition)

MI of polylactic acid composition: JIS K721
Measured according to method 0. (Measurement temperature 190 ° C, orifice diameter 2 mm, load of 21.6 kg)

Expansion ratio: The volume of the expandable particles before expansion and the volume of the expanded particles were measured using a measuring cylinder, and the expansion ratio was determined by the following equation. Expansion ratio (times) = volume of pre-expanded particles / volume of pellets impregnated with blowing agent

Evaluation of molded article Tensile strength: Measured according to JIS K-6767. Sample: Prepared by cutting out a molded product of 300 × 300 × 30 mm.

Flexibility evaluation: Bending stress: Measured according to JIS K-7221. Specimen: 300 × 300 × 30 mm molded product, length 15
It is made by cutting out a shape object of 0 mm, width 25 mm and height 20 mm. Measurement: Using a Tensilon tester, 100 mm between two supports
By pressing and bending the central part between the supports at 10 mm / min,
The 10% strain stress (kgf / cm ² ) was measured.

Compressive stress: Measured according to JIS K-7220. Specimen: 300 × 300 × 60 mm molded product to length 10
It is made by cutting out a shape object of 0 mm, width 100 mm and height 50 mm. Measurement: Using a Tensilon tester, compression was performed at a compression speed of 10 mm / min, and a 10% strain stress (kgf / cm ² ) was measured.

Buffering property: The dynamic buffering coefficient was measured. Specimen: 300 × 300 × 60 mm molded product to length 10
It is made by cutting out a shape object of 0 mm, width 100 mm and thickness 50 mm. Measurement: Using a CST320 type tester manufactured by Yoshida Seiki Co., Ltd., measuring the impact load, thickness displacement, and maximum acceleration while changing the falling weight with a falling height of 35 cm and obtaining the minimum acceleration from the load-maximum acceleration diagram. The dynamic buffer coefficient was calculated by the following equation. Buffer coefficient = minimum acceleration × ｛(fall height + compression displacement) /
Sample thickness｝

Chemical resistance: 30 × 30 × 3 from the above molded product
A test piece of 0 mm was cut out, immersed in ethyl alcohol at 25 ° C., and after 24 hours, the condition of the test piece was visually evaluated.

Production Example 1: Production Example of Polylactic Acid Commercially available L-lactide and D-lactide were each purified by recrystallization using ethyl acetate. Purified L-lactide, D-lactide and tin octylate as a catalyst were added as a catalyst in an amount of 10 ppm as tin, charged into an autoclave with a stirrer so as to have the composition shown in Table 1, degassed under reduced pressure, and N2
Under an atmosphere, the mixture was heated to a polymerization temperature of 170 ° C to 190 ° C for 2 hours to perform ring-opening polymerization. After completion of the reaction, the polymer was taken out of the autoclave, and the melt viscosity (MI) was measured.
A polymer having an I of 3 to 5 was obtained.

Production Example 2: Production Example of Polylactic Acid Composition Next, the polymer was dried until the water content became 1000 ppm or less, and then 3% by weight of talc based on the polymer was used. After blending 1% by weight of 8 equivalents / mol of diphenylmethane polyisocyanate, the mixture is fed to a twin-screw kneader under the conditions of a rotation speed of 100 rpm, a melting temperature of 180 ° C., a residence time of 3 to 5 minutes, and a discharge rate of 10 kg / hour. The reaction was kneaded. The resulting polylactic acid composition was cut to obtain particles having a diameter of about 1.5 mm. After aging, the melt viscosity (MI) was measured to obtain a polylactic acid resin composition having an MI of 3 or less. The results are shown in Table 1.

[0043]

[Table 1]

Production Example 3: Production Example of Expandable Particles 1000 parts of the polylactic acid composition exemplified in Production Example 2, 300 parts of isopentane, and 50 parts of methanol were charged into a rotary autoclave at a temperature of 80 to 90 ° C., a rotation number of 3 rpm, and 2 rpm. After holding for a time, the mixture was cooled to obtain expandable particles having an impregnation ratio of 8 to 15%.

Production Example 4: Production Example of Expanded Particles A mixture obtained by previously blending the expandable particles and 0.05% by weight of magnesium stearate as an antiblocking agent was mixed with a prefoaming machine (DYHL-30, Daisen Industries Co., Ltd.).
0) and about 30 kg with steam at 80-90 ° C.
Hold for seconds to 1 minute. After the obtained expanded particles were air-dried, expanded particles having an expansion ratio of 2 to 40 times were obtained.

Production Example 5: Production Example of Molded Product After the foamed particles exemplified in Production Example 4 were aged for 24 hours, the foamed particles and the specific biodegradable resin had an average particle size of 0.1%.
A mixture obtained by blending a predetermined amount of 1 mm powder into
A foam molding machine (Daisen Industries Co., Ltd. DS-30) equipped with a 300 × 30 mm or 300 × 300 × 60 mm mold.
0L-MC), steam pressure 0.3kgf / cm
^2. Processed for 10 to 30 seconds and molded to obtain a molded product.

Examples 1 to 4 and Comparative Examples 1 to 3 The polylactic acid compositions P1 to P6 produced by the methods exemplified in Production Examples 1 and 2 and the polystyrene particles as a control were treated by the method exemplified in Production Example 3. Thus, expandable particles having an impregnation ratio of 8 to 12% by weight were obtained. Then, the expandable particles were prepared in Production Example 4
The foamed particles were obtained by the treatment under the conditions of a steam temperature of 85 ° C. and a treatment time of 45 seconds according to the method exemplified in (1). The control polystyrene particles were foamed at a steam temperature of 95 ° C. for 60 seconds. The obtained expanded particles were treated with polybutylene succinate particles by the method exemplified in Production Example 5 for 10 minutes to the expanded particles.
% By weight and molding was performed to obtain each molded product, and the physical properties of these molded products were evaluated.

[0048]

[Table 2]

Evaluation Result P1 has high crystallinity and high crystallinity, and therefore has an extremely low expansion ratio and cannot be used as a foam. P2 to P5
The preferred results of the present invention were almost the same as those of the polystyrene foam molded article having the same flexibility and cushioning coefficient as represented by the bending stress and the compressive stress, which are the objects of the present invention.

Examples 2, 5 to 8, Comparative Examples 3 to 5 The polylactic acid composition P3 produced by the method exemplified in Production Examples 1 and 2 and the polystin particles as a control were treated by the method exemplified in Production Example 3. Thus, expandable particles having an impregnation ratio of 9 to 12% by weight were obtained. Next, the expandable particles were treated under the conditions of a steam temperature of 85 ° C. and a treatment time of 45 seconds by the method exemplified in Production Example 4 to obtain expanded particles. The control polystyrene particles were foamed at a steam temperature of 95 ° C. for 60 seconds.
To the obtained foamed particles, the biodegradable resin shown in Table 3 was added in a manner as exemplified in Production Example 5 by 10% by weight based on the foamed particles.
Mixing and molding were performed to obtain respective molded products, and the physical properties of these molded products were evaluated.

[0051]

[Table 3]

Evaluation Results In Comparative Example 4 in which a polybutylene adipate / succinate copolymer was used as the mixed biodegradable resin, the improvement of flexibility and buffering properties, which were the main objects of the present invention, was recognized, but non-crystalline properties were obtained. Because of this, the chemical resistance is poor and the heat resistance is also poor, so it is not suitable as a packaging material. Comparative Example 5, which used polylactic acid as the mixed biodegradable resin, was also a crystalline polymer and had good chemical resistance, but the flexibility and cushioning properties due to the high glass transition point were insufficient, and the packaging material was poor. Is ineligible. Examples 2 to 5 to 8 in which a thermoplastic polyurethane in which polybutylene adipate, polybutylene succinate, polycaprolactone, polyhydroxybutyrate, and polybutylene adipate were used for the soft segment were used as the mixed biodegradable resin were all used in bending stress. The flexibility represented by compressive stress and the cushioning property were greatly improved, and reached the same level as the molded article of expanded polystyrene.

Examples 2, 9 to 14, Comparative Examples 3, 6 to 7 The polylactic acid composition P3 produced by the method exemplified in Production Examples 1 and 2 and the polystin particles as a control were prepared by the method exemplified in Production Example 3. To obtain expandable particles having an impregnation ratio of 11% by weight. Next, the expandable particles were treated under the conditions of a steam temperature of 85 ° C. and a treatment time of 45 seconds by the method exemplified in Production Example 4 to obtain expanded particles. The control polystyrene particles are as follows:
The foaming treatment was performed at a steam temperature of 95 ° C. for 60 seconds. Production Example 5 of polybrylene succinate on the obtained expanded particles
In the method exemplified in the above, a predetermined amount is mixed with the expanded particles,
Molding was performed to obtain each molded product, and the physical properties of these molded products were evaluated.

[0054]

[Table 4]

Evaluation Results Comparative Example 6, in which no polybutylene succinate was added to the expanded particles, had poor flexibility and buffering properties typified by bending stress and compressive stress, whereas polybutylene succinate did not. The molded article mixed with 1% by weight greatly improved both flexibility and cushioning property. This improvement tendency increases with the amount of polybutylene succinate added, but if it exceeds 20% by weight, the effect of the properties of the resin gradually increases. The mixing amount is 5
If the content exceeds 0% by weight, both the flexibility and the buffering property are reduced, deviating from the object of the present invention, resulting in unfavorable results. From these results, the proper mixing amount was 1 to 50% by weight. Among these, a preferred range is 3 to 20% by weight, and a molded product in this range has the same level of flexibility and cushioning properties as a foamed polystyrene molded product.

[0056]

As described above, the biodegradable foamed particles of the present invention and the molded product thereof have a sufficient function as a packaging material, and have been used for foaming, heat resistance and mechanical properties. Polystyrene (PS) can be obtained at a high production efficiency and contributes to global environmental protection.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08L 67:02) (C08L 67/04 (C08L 67/04 75:06) 75:06) B29K 67:00 B29K 67:00 75:00 75:00 105: 04 105: 04 B65D 1/00 A (72) Inventor Seiji Yoshimoto 4-1 Kanebocho, Hofu City, Yamaguchi Prefecture Inside Kanebo Goden Co., Ltd. (72) Inventor Yama Masahiro 4-1 Kanebo-cho, Hofu-shi, Yamaguchi Prefecture Kanebo Gosen Co., Ltd. (72) Inventor Tsunahiro Nakae 516 F-term at 276 Osaki, Ofu-shi, Yamaguchi Prefecture (Reference) 3E033 AA20 BA13 BB01 CA20 4F074 AA66 AA68 AA81 AA98 AC32 AD13 AG20 BA31 BA39 BA73 CA23 CA30 CA34 CA39 CA49 CA53 CC04Y CC04Z CC07Z CC22Z CC29Z CC47 DA24 DA33 4F212 AA24 AA31 AG20 UA05 UB01 UF01 4J002 CF032 CF181 CF182 CK032 GG02

Claims (6)

[Claims] 1. The weight ratio of L-form to D-form is 95/5 to 60
When producing a foamed product mainly composed of polylactic acid in the range of / 40, foamed particles mainly composed of polylactic acid are produced in advance, and a biodegradable resin having a glass transition point of 40 ° C. or lower is added to the foamed particles. A process for producing a biodegradable foamed molded product, which comprises molding after mixing. 2. The weight ratio of L-form to D-form is 92/8 to 80.
The method for producing a molded product according to claim 1, wherein a polylactic acid in the range of / 20 is used. 3. The biodegradable resin having a glass transition point of 40 ° C. or lower is composed of an aliphatic dicarboxylic acid, an aliphatic glycol and / or
The method for producing a molded article according to claim 1, wherein the molded article mainly comprises hydroxycarboxylic acid. 4. The biodegradable resin having a glass transition point of 40 ° C. or lower is polybutylene succinate, polycaprolactone or a mixture thereof.
The method for producing a molded article according to the above. 5. The method according to claim 1, wherein the biodegradable resin having a glass transition point of 40 ° C. or lower is a thermoplastic polyurethane containing polybutylene adipate as a main component. 6. The molded article according to claim 1, wherein the amount of the biodegradable resin having a glass transition point of 40 ° C. or lower is in the range of 3 to 20% by weight based on the expanded particles. Manufacturing method.