JP2001098104A - Biodegradable expanded particles and molded products thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide foamed particles which can be decomposed by microorganisms, have little impact on the global environment even when disposed after use, have high productivity, and can withstand practical use, and molded articles thereof. . Kind Code: A1 Abstract: To obtain expanded particles from expandable particles obtained by impregnating a substantially amorphous polylactic acid comprising an L-form and a D-form with an organic compound having a low boiling point, talc is previously used as a foam nucleating agent.
-20% by weight of an amorphous polylactic acid mixed and dispersed, and the surface of the expandable particles impregnated with the organic compound is coated with 0.01% of a higher fatty acid or a compound selected from metal salts, esters and amides thereof. A foamed particle and a molded product thereof, which are obtained by blending from 1 to 1% by weight.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a biodegradable composition,
TECHNICAL FIELD The present invention relates to expandable particles used for a foamed molded article mainly used as a packaging material, a foamed particle obtained from the foamable particle, and a molded product thereof, 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 that are discarded without being disposed of have become insignificant. 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. As a packaging material, its use is limited in practicality. Further, since the raw materials are petroleum and natural gas, when decomposed, carbon dioxide is newly added to carbon dioxide existing on the earth, and thus does not contribute to suppressing an increase in carbon dioxide. 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 The present invention relates to a foamed particle having biodegradability and excellent productivity, and a molded product thereof,
An object of the present invention is to provide foamed particles which can be decomposed by microorganisms, have little impact on the global environment even when disposed after use, have high productivity, and can withstand practical use, and molded articles thereof.

[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 necessary to stably produce a large amount of foamed particles in large quantities. Could not. The reason for this is that when the polylactic acid composition treated at high temperature and high pressure in an aqueous dispersion system is spouted into the atmosphere at high temperature, it becomes flocculent and does not become particles. Pre-expanding expandable beads such as expandable polystyrene beads and forming the expanded particles into a form requires spherical particles close to a true sphere, and it is impossible to form the form with a cotton-like material. In addition, when the treated polylactic acid composition is cooled to around 100 ° C. and jetted, only deformed expanded particles having a low expansion ratio are obtained, which is not resistant to mold 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, it is described in the specification that the expandable particles proposed in Japanese Patent Application Laid-Open No. Hei 5-17966 are manufactured by a method that is far from the method generally employed, and the method is not realistic. Even if foamed particles are obtained from the expanded foamed particles, a blocking phenomenon occurs in which the foamed particles are fused to each other, and it is almost impossible to efficiently perform mold forming.

The present inventors have conducted intensive studies on high-expandable particles which can be pre-expanded with high efficiency, such as expandable polystyrene beads, and in which the expanded particles can be molded in a mold. Is what you do.

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 additives for increasing the molecular weight, additives for foaming, etc., a biodegradable resin composition having practically sufficient productivity was found, and an invention was proposed (JP-A-Hei). Was. However, although the resin composition obtained by the invention can obtain expanded particles having a high expansion ratio,
In the process of obtaining expanded particles by heat treatment from the expandable particles, it has been found that the expanded particles are fused to each other, causing a so-called blocking phenomenon, and the acquisition rate of unfused independent expanded particles is reduced. Japanese Patent Application Laid-Open No. 8-253617 proposes a blocking inhibitor, but as a result of additional tests by the present inventors, it has been found that even with this proposal, blocking cannot be sufficiently avoided. That is, when the added amount of the anti-blocking agent is small, the effect can hardly be expected, and when the added amount is increased, the anti-blocking effect is improved. However, a molded product from the obtained expanded particles, particularly a molded product having a thickness of 50 mm or more. However, it is difficult to obtain a uniform foamed molded product because of the difference in fusion between the foamed particles in the surface layer and the inner layer of the molded product. This is presumably because the glass transition point is lower than that of the expanded styrene particles, and the appropriate molding temperature range is narrow.

[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, in the present invention, when foaming particles are obtained from foaming particles obtained by impregnating a substantially amorphous polylactic acid composed of L-form and D-form with an organic compound having a low boiling point, talc is previously used as a foam nucleating agent. A compound selected from a higher fatty acid or a metal salt, an ester, or an amide thereof is used on the surface of expandable particles impregnated with the organic compound by using amorphous polylactic acid mixed and dispersed at 20% by weight. A foamed particle obtained by blending 1% by weight and a molded product thereof. The present invention has been achieved by the synergistic effect of a combination of a compound selected from metal salts, esters and amides of higher fatty acids, in which the amount of talc added exceeds the amount generally used.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The substantially amorphous polylactic acid comprising a D-form and an L-form according to the present invention includes polylactic acid having a melting point but a small heat of fusion. That is, DS
The heat of fusion (2nd scan @ H) by C measurement is 0.1
It is a polylactic acid of J / g or less and corresponds to 5 mol% or more in D-form copolymerization ratio. This is macromolecule
X _D described in s 255719-5729 (1992) =
It is close to 0.048 or more. Therefore, the copolymerization ratio of the D-form and the L-form of the polylactic acid used in the present invention needs to be 5 to 40 mol% for the D-form, and more preferably 8 to 20 mol%. In particular, when expanded particles having a high expansion ratio are required, the D-form having no heat of fusion (2nd scan @ H) is preferably 8 to 20 mol%.

If the molar ratio of the D-form is less than 5%, the crystallinity of the polylactic acid is increased, so that the expansion ratio cannot be increased or the foaming becomes uneven. On the other hand, when the molar ratio of the D-form exceeds 40%, the heat resistance is inferior and is not suitable for use.

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 react with a viscosity-increasing agent such as polyisocyanate to obtain a polylactic acid composition having an even higher viscosity. For example, 10
In order to obtain expanded particles having a high expansion ratio of 2 times or more, it is desirable that the melt viscosity (MI) of the composition is 5 or less, preferably 1 or less.

Polylactic acid having a melt viscosity of less than 1 is difficult to produce directly from commonly used lactic acid or dimer lactide, while polylactic acid having a melt viscosity of more than 10 is easily obtained. However, the expandable particles obtained by using the polylactic acid have an extremely low expansion ratio and cannot be used practically. The reason is presumed that, even when the viscosity is increased by reacting with a viscosity increasing agent such as polyisocyanate, the branch density increases, a crosslinked structure is easily formed, and the structure inhibits foaming.

The polyisocyanate that can be used in the present invention may be any of aromatic, alicyclic and aliphatic polyisocyanates. For example, as the aromatic polyisocyanate, a polyisocyanate having a skeleton of tolylene, diphenylmethane, naphthylene, tolidine, xylene, or triphenylmethane is used. Examples of the alicyclic polyisocyanate include polyisocyanates having a skeleton of isophorone or hydrogenated diphenylmethane, and examples of the aliphatic polyisocyanates include polyisocyanates having a skeleton of hexamethylene or lysine. Among them, tolylene, diphenylmethane, and especially diphenylmethane are preferably used from the viewpoint of versatility, handleability, weather resistance and the like.

Next, talc to be mixed and dispersed in the polylactic acid used in the present invention is 1 to 20% by weight based on the polylactic acid.
Is required, and more preferably, the amount is 2 to 10% by weight. In Japanese Patent Application Laid-Open No. 8-253617, the content of the inorganic powder containing talc is 1.5% by weight or less, especially 0.00%.
Generally, the amount used is 0.5% by weight or less, as described above as being desirably 5 to 1.0% by weight.

On the other hand, in order to efficiently obtain expanded particles having extremely low blocking properties, which is the object of the present invention, it is necessary to use talc in combination with a compound selected from metal salts, esters and amides of higher fatty acids described later. If the amount used is less than 1% by weight, it is insufficient, and the acquisition rate of unfused, independent foamed particles will be reduced. On the other hand, when the use amount of talc exceeds 20% by weight, the molecular weight of polylactic acid decreases, the expansion ratio decreases, and the molded product obtained from the expanded particles becomes rigid, and the function as a packaging material deteriorates, which is not 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. When the average particle size is within this range, there is a sufficient foaming starting point as a foam nucleating agent, and the stretching of the foam cell membrane is not hindered. As a result, a high foaming ratio is easily obtained. In many cases, the thickness of the foam cell membrane is several μm.

The method of adding and dispersing talc to the polylactic acid used in the present invention may be any of a polymerization step of obtaining polylactic acid from lactide and a method of melt-kneading polylactic acid and talc with a kneader or the like. In order to add and disperse talc, 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. Examples of the blowing agent used herein include propane, n-butane, isobutane, n-pentane, isopentane, cyclopentane, hydrocarbons such as hexane, methylene chloride, methyl chloride, halogenated hydrocarbons such as dichlorodifluoromethane, dimethyl ether,
Ethers such as methyl ethyl ether are used.
Alcohols having 1 to 4 carbon atoms, ketones, ether, benzene, toluene and the like are mainly used as foaming assistants.

The impregnating of the foaming agent and the foaming aid can be carried out by a usual method, and can be carried out in an aqueous dispersion or non-aqueous system under heating and under high pressure. For example, a predetermined amount of polylactic acid, a foaming agent, and a foaming aid are charged into an autoclave, and the foamed particles can be easily obtained by heating for several hours while maintaining the internal temperature at 80 to 90 ° C.

Next, in order to efficiently produce the unfused independent foamed particles, which is an object of the present invention, at a high acquisition rate, a compound selected from a higher fatty acid or a metal salt, ester, or amide thereof is mixed with the above foamable foam. 0.01 to 3% by weight on the surface of the particles,
Preferably, 0.02 to 0.1% by weight is required.

The higher fatty acid referred to in the present invention is a compound having 12 carbon atoms.
The above aliphatic carboxylic acids are meant. Similarly, metal salts of higher fatty acids are metal salts of aliphatic carboxylic acids having 12 or more carbon atoms. A carboxylic acid having less than 12 carbon atoms has an unpleasant odor,
Further, the metal salt is unsuitable because the melting point of the compound increases.

Examples of the carboxylic acids having 12 or more carbon atoms include monocarboxylic acids such as lauric acid, palmitic acid and stearic acid, and dicarboxylic acids such as dimer acid.
The metal ion of the metal salt includes aluminum, zinc, calcium, barium, and magnesium. Of these metal salts of higher fatty acids, aluminum, zinc and magnesium stearate are preferably used. As the ester of the higher fatty acid, any aliphatic alcohol may be used, but the use of an alcohol having a large number of carbon atoms is advantageous for preventing blocking. As the amide of the higher fatty acid, any aliphatic amine may be used, but it is necessary to consider the toxicity at the time of hydrolysis. In view of these, stearic amide and palmitic amide are preferable.

As described above, the amount of the higher fatty acid or a compound selected from metal salts, esters, and amides thereof is 0.01 to 1% by weight, preferably 0.02 to 0. It is necessary to add 1% by weight.
When the content is less than 0.01% by weight, no substantial effect is recognized. When the content exceeds 1% by weight, the effect of preventing blocking is sufficient. It becomes difficult to uniformly fuse the expanded particles between the layer and the inner layer.

The compound selected from the higher fatty acids or metal salts, esters and amides thereof may be added to the expandable particles of the present invention by any known method, for example, a rotary type such as a tumbler. If the mixer is used, it can be produced efficiently. It is preferable to take care not to raise the temperature of the expandable particles during mixing.

However, the object of the present invention is not attained by using talc alone or the compound selected from higher fatty acids or metal salts, esters and amides according to the above specifications. Expanded particles for the purpose of the present invention, talc of the above specifications and higher fatty acids of the above specifications or their metal salts, esters,
The purpose is achieved for the first time by a synergistic effect by using a compound selected from amides in combination.

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

[0030]

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.

(Evaluation method) MI of polylactic acid: JIS
Measured by a method according to K7210. (Measurement temperature 190
℃, orifice diameter 2mm, 2.16kg load)

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 foamed molded article Tensile strength: Measured according to JIS K-6767. Sample: Prepared by cutting out from a molded product of 300 × 300 × 30 mm. Moldability evaluation: 300 × 300 × 60 mm molded product or 3
The central part of the molded product of 00 × 300 × 30 mm was cut, and the uniformity of molding was visually evaluated. The surface layer and the inner layer are uniformly fused in the same state: ○ (good) The foamed particles are slightly inadequately fusible at the center of the inner layer: 発 泡 The foamed particles are clearly poorly fusible in the center of the inner layer:
× (impossible)

Heat resistance: 100 × 100 ×
A test piece of 30 mm was cut out and evaluated by dimensional change when treated at 60 ° C. in an oven for 2 hours. ：: No change at all 変 化: Change of 1% or less ：: Change of 1 to 5% ×: Change of 5% or more

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, stannous octoate as D- lactide and the catalyst was 10ppm added as tin, were charged into an autoclave equipped with a stirrer so that the composition of Table 1, after vacuum degassing, N ₂
Ring-opening polymerization was performed under each polymerization condition under an atmosphere. After completion of the reaction, the polymer was taken out of the autoclave to obtain a polymer.

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 a predetermined amount of talc having various average particle diameters was added. 2.8 equivalents of diphenylmethane polyisocyanate was added to the polymer at 1 equivalent.
After blending the weight%, the mixture is supplied to a twin-screw kneader, the number of rotations is 100 rpm, the melting temperature is 180 ° C, the residence time is 3 to 5 minutes,
The reaction was kneaded under the conditions of a discharge rate of 10 kg / hour. The obtained polylactic acid composition was cut to obtain particles having a diameter of about 1.5 mm. The results are shown in Table 1.

[0038]

[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 in a rotary autoclave, and the temperature was 80 to 90 ° C., the number of rotations was 3 rpm, 2
After keeping for a time, the mixture was cooled to obtain expandable particles having an impregnation ratio of 13 to 20%.

Production Example 4: Production Example of Expanded Particles A mixture obtained by preliminarily blending the expandable particles and a compound selected from a higher fatty acid or a metal salt, an ester, or an amide thereof in a predetermined amount is subjected to a prefoaming machine (DYHL Industrial Co., Ltd. DYHL). −
About 300 kg), and kept at 80 to 90 ° C. for 30 seconds to 1 minute with steam. After the obtained foamed particles were air-dried, the fused particles and the unfused independent particles were separated using a sieve having a mesh size of 5 mm, and the acquisition rate of the unfused independent particles was calculated by the following equation. Acquisition rate of independent particles (%) = (weight of independent particles / weight of treated expanded particles) × 100 Blocking property (%) = 100−acquisition rate of independent particles (%)

Production Example 5: Production Example of Molded Product Foam molding machine (DS-300L-M, Daisen Industries Co., Ltd.)
C) 300x300x30mm or 300x300x
A mold having a size of 60 mm was set, and the foamed particles exemplified in Production Example 4 were aged for 24 hours and then filled, and then steam pressure was 0.5
The mixture was treated at a rate of 10 kg / cm ² for 10 to 30 seconds and molded to obtain a molded product.

Examples 1-4, Comparative Examples 1-2 Polylactic acid compositions P1, P2, P6, P15, P16 and P17 produced by the methods exemplified in Production Examples 1 and 2 were prepared by the method exemplified in Production Example 3. The foamed particles are obtained by blending 0.05% by weight of magnesium stearate with the particles, and the respective foamed particles are obtained by the method exemplified in Production Example 4, and the expansion ratio and the blocking property are evaluated. The heat resistance of the molded product obtained by the method exemplified in Production Example 5 was evaluated.

[0043]

[Table 2]

Evaluation Results Since P1 has high crystallinity and high crystallinity, it has an extremely low expansion ratio and cannot be used as a foam. Since the crystallinity of P2 was very small as compared with that of P1, the foaming property was improved, and both the blocking property and the heat resistance were good. P6, P1
5 and P16 were completely amorphous, and thus had good foaming properties and good blocking properties and heat resistance. However, despite the fact that P17 was amorphous, the heat resistance of the resin tended to decrease slightly, the foaming property was reduced, and the blocking property was deteriorated. Further, the heat resistance of the molded product was also poor.

Examples 2 to 5 and Comparative Examples 3 to 5 The polylactic acid compositions P3 to P11 produced by the methods exemplified in Production Examples 1 and 2 were used to obtain expandable particles by the method exemplified in Production Example 3. , The particles contain magnesium stearate.
The foamed particles were blended in an amount of 0.05% by weight, and the respective foamed particles were obtained by the method exemplified in Production Example 4. The expansion ratio and the blocking property were evaluated. Was evaluated. However, in Comparative Example 5, magnesium stearate was not added.

[0046]

[Table 3]

Evaluation Results In Comparative Example 3, although the amorphous polylactic acid composition P3 was used, the blocking property was high and the production efficiency was low.
This is because the amount of talc added was as low as 0.5% by weight, and the expansion ratio also tended to be low. The blocking property decreases with the addition amount of talc, and as shown in P4 to P10, 1% by weight, especially in a range not usually used.
Above the weight%, the blocking properties were significantly improved. The expansion ratio also had the same tendency, and the evaluation of the molded product was good. . On the other hand, when the talc addition amount of P11 exceeds 20% by weight, the blocking ratio is good, but the expansion ratio decreases. Furthermore, as shown in Comparative Example 5, even if the P6 resin composition is used, the blocking property is extremely high unless magnesium stearate is added, and the product cannot be used due to poor productivity.

Examples 2, 11 to 12, Comparative Example 6 Expandable particles were obtained from the polylactic acid compositions P6, P12 to P13 produced by the methods exemplified in Production Examples 1 and 2 by the method exemplified in Production Example 3. , The particles containing zinc stearate at 0.
The foamed particles were blended in an amount of 0.05% by weight, and the respective foamed particles were obtained by the method exemplified in Production Example 4. The expansion ratio and the blocking property were evaluated. Was evaluated.

[0049]

[Table 4]

Evaluation Results Even if the particle size of talc was changed, when zinc stearate was not added, as shown in Comparative Example 6, the blocking property was poor and it could not be used.

Examples 2, 13 to 26, Comparative Examples 7 to 10 The polylactic acid composition P6 produced by the method exemplified in Production Examples 1 and 2 was used to obtain expandable particles by the method exemplified in Production Example 3. Higher fatty acids or metal salts, esters,
A predetermined amount of a compound selected from amides is blended, each expanded particle is obtained by the method exemplified in Production Example 4, the expansion ratio and the blocking property are evaluated, and the expanded particles are obtained by the method exemplified in Production Example 5. The heat resistance of the molded product was evaluated.

[0052]

[Table 5]

Evaluation Results Higher fatty acids having less than 12 carbon atoms have an unpleasant odor (Comparative Examples 7 and 8) and cannot be used as a packaging material. Higher fatty acids having 12 or more carbon atoms have almost no unpleasant odor, and those obtained by blending 0.05% by weight of these higher fatty acids are described in Example 1.
As seen in 3, 14, and 15, both the blocking expansion ratio and the molded product evaluation were good. As a result of various evaluations of fatty acid metal salts, magnesium, zinc, aluminum, and calcium salts were preferable. Examples of these stearates and a blend amount of 0.05% by weight are shown in Example 2 and Examples 21 to 23. On the other hand, as a result of examining the blending amount of the higher fatty acid metal salt, if the amount is less than 0.01% by weight, the improvement of the blocking property cannot be expected so much. It was good. However, when the blending amount exceeds 1% by weight, the blocking property is good, but the fusion property of the foamed particles at the time of molding is reduced, and a difference occurs in the fusion of the foamed particles between the molding surface and the inner layer. In particular, it was remarkable in a molded product having a thickness of 50 mm or more (Comparative Examples 9, 10 and Examples 2, 16 to 20). Further, those having a blend amount of more than 1% by weight showed a sharp decrease in mechanical strength.

[0054]

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 Continuing on the front page (72) Inventor Satoshi Yoshimoto 4-1 Kanebo-cho, Hofu-shi, Yamaguchi Prefecture Inside Kanebo Goden Co., Ltd. (72) Inventor Masahiro 4-1 4-1 Kanebo-cho, Hofu City, Yamaguchi Prefecture Kanebo God Co., Ltd. (72) Inventor Tsunadai Nakae 516 F-term at 276 Osaki, Hofu City, Yamaguchi Prefecture (Reference) 3E033 AA20 BA13 BB04 CA20 4F074 AA65 AC32 AD10 AD11 AD13 BA35 BA36 BA37 BA38 BA39 BA44 BA45 BA53 BA75 BC11 CA32 CA34 CA45 CC47 DA02 DA08 DA33

Claims (7)

[Claims] 1. A foamed particle mainly composed of substantially amorphous polylactic acid comprising an L-form and a D-form, wherein said polylactic acid is L-form.
The ratio of body to D-form is in the range of 95/5 to 60/40,
A higher fatty acid or a metal salt thereof on the surface of expandable particles obtained by impregnating a low-boiling organic compound into an amorphous polylactic acid composition in which 1 to 20% by weight of talc is previously mixed and dispersed as a thickener and a foam nucleating agent; 0.0% of a compound selected from an ester and an amide
A foamed particle obtained by mixing 1 to 1% by weight. 2. The ratio between L-form and D-form is 92/8 to 80/2.
The foamed particles according to claim 1, wherein polylactic acid in the range of 0 is used. 3. The compounding amount of talc is 2 to polylactic acid.
The foamed particle according to claim 1, wherein the content is 10% by weight. 4. The expanded particles according to claim 1, wherein the metal salt compound of a higher fatty acid is a group selected from magnesium stearate, zinc and aluminum. 5. The expanded particles according to claim 1, wherein the ester compound of a higher fatty acid is an ester with stearic acid or an aliphatic alcohol. 6. The foamed particles according to claim 1, wherein the amide compound of a higher fatty acid is stearic acid amide. 7. A molded article comprising the expanded particles according to claim 1.