JPH11116788A - Polylactic acid resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a resin compsn. which has both softness and heat resistance by compounding a high-molecular component comprising polylactic acid and a biodegradable aliph. polyester in a specified ratio with a specified amt. of a biodegradable plasticizer. SOLUTION: This compsn. contains 100 pts.wt. polymer component comprising 90-50 wt.% polylactic acid and 10-50 wt.% biodegradable polyester having an m.p. of 80-250 deg.C, 5-25 pts.wt. biodegradable plasticizer, and if necessary an inorg. filler (e.g. silica), a lubricant (e.g. an aliph. carboxamide), an antioxidant, a heat stabilizer, an ultraviolet absorber, etc., can be formed into a film having a thickness of 5-1,000 μm, and has an elastic modulus of 2,000-10,000 kgf/cm<2> and a heat resistance temp. of 60-120 deg.C. The biodegradable aliph. polyester has a wt. average mol.wt. of 10,000-1,000,000, and its examples are polyethylene oxalate and polybutylene succinate. The biodegradable plasticizer is selected from among triacetylene, acetyltributyl citrate, dibutyl sebacate, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a lactic acid-based resin composition and a molded product thereof. More flexibility,
The present invention relates to a lactic acid-based resin composition having excellent heat resistance and further having excellent decomposability in compost after use, and a molded product thereof.

[0002]

2. Description of the Related Art In general, resins having excellent flexibility, heat resistance and water resistance include resins such as polyethylene, polypropylene, soft polyvinyl chloride, and polyethylene terephthalate, and are used for garbage bags, packaging bags, and the like. Have been. However, when these resins are discarded after use,
In addition to increasing the amount of garbage, it is hardly decomposed in the natural environment, so it remains semi-permanently even when buried.
In addition, abandoned plastics have caused problems such as spoiling the landscape and destroying the living environment of marine life.

On the other hand, as a biodegradable polymer of a thermoplastic resin, polylactic acid, a copolymer of lactic acid with another aliphatic hydroxycarboxylic acid, an aliphatic polyhydric alcohol and an aliphatic polycarboxylic acid are used. Polyester and the like have been developed.

Some of these polymers are 100% biodegradable within a few months to a year in animals or, when placed in soil or seawater, begin to degrade within weeks in moist environments. Disappears in about one to several years. Furthermore, the decomposition products have the property of becoming lactic acid, carbon dioxide, and water that are harmless to the human body.

[0005] In particular, polylactic acid, in particular, has recently been able to produce L-lactic acid as a raw material in large quantities and inexpensively by a fermentation method, has a high decomposition rate in compost, has resistance to mold, and has a high resistance to food. Due to its excellent characteristics such as odor resistance and coloring resistance, it is expected that its field of use will be expanded.

[0006] However, polylactic acid has high rigidity and cannot be said to be a suitable resin for applications requiring flexibility such as films and packaging materials. Generally, as a technique for softening a resin, methods such as addition of a plasticizer, copolymerization, and blending of a soft polymer are known. However,
In the method described above, even if sufficient flexibility can be imparted, the glass transition temperature of the resin composition decreases, and as a result,
In the case of the method of adding a plasticizer, a change in physical properties such as crystallization and hardening is caused by the normal environmental temperature, and further a problem such as bleeding of the plasticizer occurs. There are problems.

In one method, considering the biodegradability which is one of the problems, the resin to be blended is limited to a biodegradable resin having flexibility. Such resins include, for example, polybutylene succinate, polyethylene succinate, polycaprolactone, etc., as already disclosed in JP-A-8-245866 and JP-A-9-11.
No. 1107 is disclosed. However, in this method, the polylactic acid-based resin composition has sufficient flexibility (having an elastic modulus of 1).
000 kgf / cm ² or less, a large amount (for example, in the case of polybutylene succinate, 60 w
t% or more), and as a result, the characteristics of polylactic acid as described above are impaired. As described above, it has been impossible to impart flexibility and heat resistance without deteriorating the characteristics of polylactic acid by using the conventional technology.

[0008]

One of the problems to be solved by the present invention is to provide a polylactic acid-based resin composition characterized by having both flexibility and heat resistance.
One of the problems to be solved by the present invention is to provide a molded product made of a polylactic acid-based resin composition having both flexibility and heat resistance. One of the problems to be solved by the present invention is to provide a film or sheet comprising a polylactic acid-based resin composition characterized by having both flexibility and heat resistance. An object of the present invention is to develop a polylactic acid-based resin composition having flexibility and heat resistance without impairing the characteristics of polylactic acid, and a molded article obtained therefrom. More specifically, the flexibility (elasticity is 2000) such as polypropylene, polyethylene and polyvinyl chloride used for garbage bags and packaging materials.
〜１０10000 kgf / cm ² ) and heat resistance (heat resistance temperature is 6
0 to 120 ° C.) and a biodegradable polylactic acid-based resin composition, and a film and a sheet made of the same.

[0009]

Means for Solving the Problems As a result of intensive studies on polylactic acid, the present inventors have found that a specific soft biodegradable resin and a mixture of polylactic acid and biodegradable resin are not compatible with each other. By mixing a good specific plasticizer, a polylactic acid-based resin composition that satisfies the above problem was found, and the present invention was completed. That is, the present invention provides the following [1] to
It is specified by the items described in [8].

[1] Polylactic acid (a1) having a melting point of 80
Aliphatic polyester (a)
A polylactic acid-based resin composition comprising a polymer component (A) containing 2) and a biodegradable plasticizer (B), wherein the polylactic acid (a1) and the aliphatic polyester (a2) ) Based on the total weight of the polylactic acid (a
1) contains 90 to 50% by weight, and the aliphatic polyester (a2) contains 10 to 50% by weight, and the composition ratio of the plasticizer (B) is 100 parts by weight of the polymer component (A). A polylactic acid-based resin composition having flexibility and heat resistance, wherein the plasticizer (B) is equivalent to 5 to 25 parts by weight.

[2] The aliphatic polyester (a2) is
The polybutylene succinate described in [1],
A polylactic acid-based resin composition having both flexibility and heat resistance.

[3] The plasticizer (B) is at least one selected from the group consisting of aliphatic polybasic acid esters, aliphatic polyhydric alcohol esters, and oxyacid esters. The polylactic acid-based resin composition described above, which has both flexibility and heat resistance.

[4] The plasticizer (B) according to [1] or [2], wherein the plasticizer (B) is at least one selected from the group consisting of acetyltributylcitrate, triacetin, dibutylsebacate, and triethyleneglycol diacetate. A polylactic acid-based resin composition characterized by having both flexibility and heat resistance.

[5] The flexibility and the elastic modulus are from 2000 to 2000.
It is equivalent to 10,000 kgf / cm ² .
The polylactic acid-based resin composition according to any one of [1] to [4], having both flexibility and heat resistance.

[6] Heat resistance, heat resistance temperature is 60 to 1
The polylactic acid-based resin composition according to any one of [1] to [5], which is equivalent to a temperature of 20 ° C., characterized by having both flexibility and heat resistance.

[7] A molded product comprising a polylactic acid-based resin composition according to any one of [1] to [6], having both flexibility and heat resistance.

[8] A film having a thickness of 5 to 1000 μm, comprising a polylactic acid resin composition having both flexibility and heat resistance described in any one of [1] to [6]. Sheet.

[9] A blown film of 5 to 1000 μm comprising a polylactic acid resin composition according to any one of [1] to [6], characterized by having both flexibility and heat resistance. Or an inflation sheet.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. [Polylactic acid (a1)] In the present invention, polylactic acid (a)
Specific examples of lactic acid as a raw material of 1) include L-lactic acid and D-lactic acid.
-Lactic acid, DL-lactic acid or a mixture thereof, or lactide which is a cyclic dimer of lactic acid. However, when the obtained polylactic acid is used by mixing L-lactic acid and D-lactic acid, it is necessary that either L-lactic acid or D-lactic acid is 75% by weight or more. Specific examples of the method for producing polylactic acid (a1) used in the present invention include:
For example, a method of performing direct dehydration polycondensation using lactic acid or a mixture of lactic acid and an aliphatic hydroxycarboxylic acid as a raw material (for example, U.S. Pat.
SP 5,310,865), a ring-opening polymerization method for melt-polymerizing a cyclic dimer of lactic acid (lactide) (for example, a production method disclosed in US Pat. No. 2,758,987). Method), cyclic dimer of lactic acid and aliphatic hydroxycarboxylic acid,
For example, a ring-opening polymerization method in which lactide or glycolide and ε-caprolactone are melt-polymerized in the presence of a catalyst (for example, a production method disclosed in US Pat. No. 4,057,537), lactic acid, aliphatic divalent A method of directly dehydrating and polycondensing a mixture of an alcohol and an aliphatic dibasic acid (for example, a production method disclosed in US Pat. No. 5,428,126);
5) A method of condensing a polymer of polylactic acid, an aliphatic dihydric alcohol and an aliphatic dibasic acid in the presence of an organic solvent (for example, a production method disclosed in European Patent Publication 0712880 A2) and the like. However, the production method is not particularly limited. Further, a small amount of an aliphatic polyhydric alcohol such as glycerin, an aliphatic polybasic acid such as butanetetracarboxylic acid, and a polyhydric alcohol such as a polysaccharide may coexist and may be copolymerized. The molecular weight may be increased by using a binder (polymer chain extender) such as a diisocyanate compound.

[Aliphatic polyester (a2)] The aliphatic polyester (a2) in the present invention has a biodegradability that can be produced by variously combining an aliphatic hydroxycarboxylic acid, an aliphatic dihydric alcohol and an aliphatic dibasic acid. It is a polymer. As a method for producing the aliphatic polyester (a2), a method similar to the method for producing the polylactic acid (a1) can be used, but it is not limited thereto.

[Aliphatic hydroxycarboxylic acid] Specific examples of the aliphatic hydroxycarboxylic acid include glycolic acid,
Examples thereof include 3-hydroxybutyric acid, 4-hydroxybutyric acid, 3-hydroxyvaleric acid, 4-hydroxyvaleric acid, and 6-hydroxycaproic acid. Further, cyclic esters of aliphatic hydroxycarboxylic acids, for example, glycolic acid Examples include glycolide which is a dimer and ε-caprolactone which is a cyclic ester of 6-hydroxycaproic acid. These can be used alone or in combination of two or more.

[Aliphatic dihydric alcohol] Specific examples of the aliphatic dihydric alcohol include ethylene glycol, diethylene glycol, triethylene glycol, and the like.
Polyethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol, 1,4
-Butanediol, 3-methyl-1,5-pentaneddiol, 1,6-hexanediol, 1,9-nonanediol, neopentyl glycol, polytetramethylene glycol, 1,4-cyclohexanedimethanol, 1,
4-benzenedimethanol and the like. They are,
They can be used alone or in combination of two or more.

[Aliphatic dibasic acid] Specific examples of the aliphatic dibasic acid include succinic acid, oxalic acid, malonic acid, and the like.
Glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecandioic acid, dodecandioic acid, phenylsuccinic acid, 1,4-phenylenediacetic acid, and the like. These can be used alone or in combination of two or more. In the present invention, the aliphatic polyester (a2) has a melting point of 80 ° C to 250 ° C, which can be produced by variously combining the above-mentioned aliphatic hydroxycarboxylic acid, aliphatic dihydric alcohol and aliphatic dibasic acid, and is biodegradable. There is no limitation as long as it is an aliphatic polyester having Particularly, a soft aliphatic polyester having crystallinity is preferable. Melting point of aliphatic polyester is 80 ℃
When it is lower, the heat resistance of the obtained polylactic acid-based resin composition is reduced, and conversely, when the temperature is higher than 250 ° C., the melting temperature at the time of pelletization is increased, so that the polylactic acid component is deteriorated,
It is not preferable because it tends to be colored. Preferred aliphatic polyesters include polyethylene oxalate, polybutylene oxalate, polyneopentyl glycol oxalate, polyethylene succinate, polybutylene succinate, polyhydroxybutyric acid, and a copolymer of β-hydroxybutyric acid and β-hydroxyvaleric acid. And polyethylene succinate and polybutylene succinate are particularly preferred. Further, these aliphatic polyesters may have a polymer chain extended by a binder such as diisocyanate, a small amount of an aliphatic polyhydric alcohol such as glycerin, and a small amount of fatty acid such as butanetetracarboxylic acid. Copolymerization may be carried out in the presence of polyhydric alcohols such as group polybasic acids and polysaccharides.
The weight average molecular weight (Mw) and the molecular weight distribution of the polylactic acid (a1) and the aliphatic polyester (a2) are not particularly limited as long as they can be molded. The weight average molecular weight of the polylactic acid (a1) and the aliphatic polyester (a2) used in the present invention is not particularly limited as long as they exhibit substantially sufficient mechanical properties. Mw), preferably from 1 to 1,000,000, more preferably from 3 to 500,000, even more preferably from 50 to 300,000. Generally, when the weight average molecular weight (Mw) is less than 10,000,
If the mechanical properties are not sufficient or the molecular weight exceeds 1,000,000, handling may be difficult or uneconomical.

[Polymer Component (A)] In the present invention, an aliphatic polyester (a2) is added to the polylactic acid (a1) for the purpose of imparting softness, particularly heat resistance. Therefore, an aliphatic polyester having crystallinity and having soft biodegradability is preferable. The mixing amount is preferably 90 to 50 parts by weight of polylactic acid (a1) / 10 to 50 parts by weight of the aliphatic polyester (a2), and more preferably 85 to 55 parts by weight / 100 parts by weight of the polymer component (A). 15 to 45 parts by weight, more preferably 80 to 60 parts by weight / 20 to 40 parts by weight. If the polylactic acid component exceeds 90 parts by weight, the flexibility may be insufficient. On the other hand, even if a method of softening with a plasticizer described later is used, a large amount of a plasticizer is required,
As a result, the heat resistance of the composition may be lowered, or problems such as bleeding of the plasticizer or blocking between films may occur. Conversely, when the polylactic acid component is less than 50 parts by weight, the polylactic acid tends to have a low decomposability and mold resistance in the compost having the polylactic acid. May not be used.

[Plasticizer (B)] In the present invention, the desired flexibility (elastic modulus of 10,000 kgf /
cm ² or less), it is necessary to further add a plasticizer. Plasticizer (B) used in the present invention
Is required to have biodegradability and to have good compatibility with the polymer component (A). Such plasticizers include
Examples thereof include an aliphatic polycarboxylic acid ester, an aliphatic polyhydric alcohol ester, and an oxyacid ester. Examples of the aliphatic polybasic acid ester include dimethyl adipate, di-2-ethylhexyl adipate, diisobutyl adipate, dibutyl adipate, diisodecyl adipate, dibutyl diglycol adipate, di-2-ethylhexyl adipate, dibutyl sebacate, and di-2-sebacate.
Ethylhexyl sebacate and the like.

As the aliphatic polyhydric alcohol ester,
For example, diethylene glycol dibenzoate, diethylene glycol monomethyl ether, diethylene glycol dimethyl ether, diethylene glycol monoethyl ether, diethylene glycol diethyl ether,
Diethylene glycol monobutyl ether, diethylene glycol dibutyl ether, diethylene glycol monohexyl ether, polydiethylene glycol monooleyl ether, triethylene glycol diacetate, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, polydiethylene glycol monooleyl ether, triacetin, glycerin tripropionate And the like.

Examples of the oxyacid esters include methyl acetyl ricinoleate, butyl acetyl ricinoleate, and acetyl tributyl citric acid. In particular, triacetin, acetyl tributyl citric acid, dibutyl sebacate, and triethylene glycol diacetate are preferably used because of their excellent compatibility with the polymer component (A). These can be used as one kind or as a mixture of two or more kinds.

The amount of the plasticizer (B) to be added is 5 to 25 parts by weight, preferably 7 to 20 parts by weight, more preferably 10 to 18 parts by weight, based on 100 parts by weight of the polymer component (A). If the amount of the plasticizer is less than 5 parts by weight, the plasticizing effect may be insufficient and the desired flexibility may not be provided. Conversely, if the amount is more than 25 parts by weight, the heat resistance of the composition may be poor, or the plasticizer may be inferior. Bleed-out may occur.

The polylactic acid resin composition according to the present invention comprises:
Various additives (antioxidants, ultraviolet absorbers, heat stabilizers, flame retardants, internal mold release agents, inorganic additives, antistatic agents) depending on the purpose (for example, improvement in tensile strength, heat resistance, weather resistance, etc.) , A surface wetting improving agent, an incineration aid, a lubricant such as a pigment) and the like. For example, in inflation molding and T-die extrusion molding, it is recommended to add an inorganic additive or a lubricant (aliphatic carboxylic acid amide) in order to prevent blocking and improve slippage of a film or sheet.

Examples of the inorganic additives include silica, calcium carbonate, talc, kaolin, kaolinite, zinc oxide and the like, and silica is particularly preferred. These can be used as one kind or as a mixture of two or more kinds. In general, the amount of the inorganic additive to be added is generally 100 parts by weight of the polymer component (A).
It is 0.05 to 15% by weight, preferably 0.5 to 10% by weight, and more preferably 1 to 5% by weight based on part by weight. The amount of addition is appropriately selected from the optimum amounts that provide good moldability during the desired T-die extrusion molding or inflation molding, good blocking resistance of the obtained film, and good slipperiness of the film.

[Lubricant (aliphatic carboxylic acid amide)] Aliphatic carboxylic acid amides include "10889 chemical products (1
989, Kagaku Kogyo Nippo, Nihonbashi-hama-cho, Chuo-ku, Tokyo) on page 389, right column to page 391, left column. All the descriptions are incorporated as a part of the disclosure of the specification of the present application by explicitly citing the cited documents and the cited range, and by referring to the explicitly cited ranges, the matters or disclosures described in the specification of the present application are all Items that can be directly and unambiguously derived by the trader are disclosed.

Specific examples of the aliphatic carboxylic acid amide include, for example, oleic acid amide, stearic acid amide,
Erucamide, behenic amide, N-oleyl palmitamide, N-stearyl erucamide, N, N '
Monoethylene bis (stearamide), N, N'-methylene bis (stearamide), methylol stearamide, ethylene bisoleic acid amide, ethylene bisbehenic acid amide, ethylene bis stearic acid amide,
Ethylene bislaurate amide, hexamethylene bisoleate amide, hexamethylene bisstearate amide, butylene bisstearate amide, N,
N'-dioleyl sebacic amide, N, N'-dioleyl adipamide, N, N'-distearyl adipamide, N, N'-distearyl sebacamide, m-xylylene bis stearamide , N, N '
-Distearyl isophthalamide, N, N'-distearyl terephthalamide, N-oleyl oleamide, N-stearyl oleamide, N-stearyl erucamide, N-oleyl stearamide,
N-stearyl stearamide, N-butyl-N '
Stearyl urea, N-propyl-N 'stearyl urea,
N-allyl-N 'stearyl urea, N-phenyl-N'
Examples include stearyl urea, N-stearyl-N 'stearyl urea, dimethitol oil amide, dimethyl laurate amide, dimethyl stearate amide and the like.
In particular, oleic acid amide, stearic acid amide, erucic acid amide, behenic acid amide, N-oleyl palmitamide, and N-stearyl erucic acid amide are preferably used. These may be one kind or a mixture of two or more kinds.

[Addition amount of lubricant (aliphatic carboxylic acid amide)] The addition amount of the aliphatic carboxylic acid amide is 0.05 to 10 parts by weight based on 100 parts by weight of the polymer component (A).
Preferably, 0. The amount is preferably 1 to 7.0 parts by weight, more preferably 0.3 to 5.00, and most preferably 0.5 to 3 parts by weight. As with the case of the inorganic additive, the amount of the additive is the optimum amount at which the desired moldability at the time of T-die extrusion molding or inflation molding, and the obtained film / sheet has good blocking resistance and good slipperiness. It is selected as appropriate.

[Polylactic acid-based resin composition] The method for producing the lactic acid-based resin composition is as follows: a polymer component (A) comprising polylactic acid (a1) and an aliphatic polyester (a2); and a plasticizer (B). Depending on the method, a method in which other additives are uniformly mixed using a high-speed stirrer or a low-speed stirrer and then melt-kneaded with a single-screw or multi-screw extruder having a sufficient kneading ability can be adopted. In general, the shape of the resin composition according to the present invention is preferably a pellet, a rod, a powder, or the like.

[Production and Film Production of Film and Sheet] The polylactic acid-based resin composition according to the present invention is a material suitable for production of a film or sheet. Examples of the method for forming a film, sheet, or plate-like molded body according to the present invention include inflation molding, T-die molding, and thermoforming, but the method is not particularly limited. The films and sheets of the present invention include, for example, films and sheets obtained by known and publicly-known molding methods, and there are no restrictions on the shape, size, thickness, design, and the like.

Production Technology Films and sheets comprising the resin composition according to the present invention are:
It can be manufactured by a known or publicly used extrusion method, coextrusion method, calender method, hot press method, solvent casting method, inflation method, balloon method, tenter method and the like.

Methodology of extrusion method or coextrusion method In the extrusion method or coextrusion method, a T-die, an inflation die (circular die), a flat die, a feed block / single manifold die or a single manifold die combining several feed blocks. Known or public dies can be used. In the coextrusion method, a multilayer film can be produced by using a plurality of the polymers having different properties and / or other kinds of polymers.

When the inflation method or the balloon method is adopted, biaxial simultaneous stretching can be performed, production can be performed at a relatively low cost with higher productivity, and the shape is a bag-like (seamless) shape. It is suitable for the production of bags and bags such as take-away bags, bags for preventing dew condensation on low-temperature food packs such as frozen foods and meat, and so on, and compost bags. By combining with a coextrusion method, a multilayer film can be manufactured with high productivity using a plurality of resin compositions and / or other kinds of polymers according to the present invention having different properties.

The inflation method or the balloon method can be combined with the coextrusion method. The film or sheet made of the resin composition according to the present invention can be manufactured in a roll shape, a tape shape, a cut sheet shape, a plate shape, a bag shape (seamless shape) by setting the process conditions according to the purpose. it can.

Secondary Processing The film or sheet made of the resin composition according to the present invention can be further subjected to secondary processing for imparting a two-dimensional or three-dimensional shape such as stretching, blow processing, vacuum forming and the like. Is also a suitable material.

Specific Examples of Uses Films or sheets made of the resin composition according to the present invention include shopping bags, garbage bags, compost bags,
Food and confectionery packaging film, food wrap film, cosmetic / cosmetic wrap film, pharmaceutical wrap film, herbal medicine wrap film Surgical patch wrap film applied to shoulder stiffness, sprain, etc., agricultural / horticultural film Wrap film for agricultural chemicals, film for greenhouse, bag for fertilizer, film for magnetic tape cassette products such as video and audio, film for floppy disk packaging, film for plate making, adhesive tape, tape, waterproof sheet, bag for sandbags, And the like.

The film or sheet, which is one embodiment of the molded article of the present invention, can be suitably used particularly in applications requiring degradability by utilizing its properties. By using a film or sheet, which is one embodiment of the molded article according to the present invention, as a packaging material as a food / confectionery bag, at the time of sealing the food / confectionery, by putting an oxygen absorber in the bag. In addition, the storage period and the shelf life can be greatly extended.

[0043]

The present invention will be described in detail with reference to the following examples, but it should not be construed that the present invention is limited thereto without departing from the technical scope of the present invention. The weight average molecular weight (Mw) of the polymer component (A), flexibility, heat resistance, mold resistance and biodegradability in the examples were measured by the following methods. Weight average molecular weight (Mw) Measured by gel permeation chromatography (GPC) using polystyrene as a standard, at a column temperature of 40 ° C. and a chloroform solvent. Flexibility The modulus of elasticity of the film obtained in the examples is JIS K67.
32. The flexible film described in the present invention means that the elastic modulus is 2,000 to 10,000 kgf / cm ^2.
Is shown. Heat resistance (blocking resistance) The inflation film obtained in the example was subjected to JIS Z02.
According to No. 19, the state of the film when kept under the conditions of 80 ° C./500 g load was observed. The heat-resistant film shown in the present invention means that even under the above conditions, bleeding of the plasticizer and the accompanying blocking of the films do not occur. Evaluation method Bleed of plasticizer ○ ・ ・ ・ No bleed × ・ ・ ・ Bleed Film blocking ○ ・ ・ ・ No blocking △ ・ ・ ・ Slightly blocking × ・ ・ ・ Blocking

Mold resistance A test piece of 5 cm × 5 cm was placed on a medium previously sterilized and solidified, and sprayed with a spore suspension of the following test bacterium.
After culturing for 6 months in a container at 0 ° C., the growth state of the mold was observed and evaluated. Test bacteria Aspergillus niger Rhizopusoryzae Penicillium citrinium Cladosporium cladosporoid
es Chaetomiumglobosum medium Inorganic salt agar medium (adjusted according to JIS Z-2911) Ammonium nitrate 3.0 g Potassium phosphate 1.0 g Magnesium sulfate 0.5 g Potassium chloride 0.25 g Ferrous sulfate 0.002 g Agar 25 g Evaluation method ○: Mold No growth is observed. Δ: Mold growth area is less than 1/3 ×: Mold growth area is larger than 1/3

Biodegradability A 10 cm × 10 cm press film having a thickness of 100 μm was prepared, buried in a compost having a temperature of 58 ° C. and a water content of 60%, and observed with time. Evaluation method ◎: Elimination within 7 days ○: Elimination within 8 to 14 days △: Elimination within 15 to 25 days ×: Elimination within 26 to 40 days

Production Example 1 400 g of L-latatatide and stannous octoate 0.1 g
04 g and lauryl alcohol 0.12 g were sealed in a thick cylindrical stainless steel polymerization vessel equipped with a stirrer and degassed under vacuum for 2 hours. After replacing with nitrogen gas, 200 ℃
The mixture was heated and stirred at / 10 mmHg for 2 hours. After completion of the reaction, a melt of polylactic acid was extracted from the lower outlet, air-cooled, and cut with a pelletizer. The resulting polylactic acid had a yield of 340 g, a yield of 85%, and a weight average molecular weight (M
w) 138,000.

Production Example 2 9 was added to a reactor equipped with a Dien-Stark trap.
10 kg of 0% L-lactic acid and 45 g of tin powder are charged, and 150 ° C.
After distilling water while stirring at / 50 mmHg for 3 hours, the mixture was stirred at 150 ° C / 30 mmHg for 2 hours to oligomerize. 21.1 kg of diphenyl ether was added to this oligomer, and an azeotropic dehydration reaction at 150 ° C./35 mmHg was performed. The distilled water and the solvent were separated by a water separator, and only the solvent was returned to the reactor. Two hours later, the organic solvent to be returned to the reactor was passed through a column packed with 4.6 kg of molecular sieve 3A, and then returned to the reactor.
The reaction was carried out at 17 mmHg for 20 hours to obtain a polylactic acid solution having a weight average molecular weight (Mw) of 150,000. 44 kg of dehydrated diphenyl ether was added to this solution to dilute it, and then cooled to 40 ° C., and the precipitated crystals were filtered. 12 kg of 0.5 N HCl and 12 k of ethanol
g, and the mixture was stirred at 35 ° C. for 1 hour, and then filtered.
5. Dry at 50 mmHg, polylactic acid powder 1 kg (85% yield) was obtained. This powder was melted and pelletized by an extruder to obtain polylactic acid. The weight average molecular weight (Mw) of this polymer was 1470,000.

Production Example 3 In a reactor equipped with a Dien-Stark trap,
50.5 kg of 1,4-butanediol and succinic acid
After 5 kg of tin powder and 45 g of tin powder were charged, water was distilled off while stirring at 100 ° C. for 3 hours, and the mixture was further stirred at 150 ° C./50 mmHg for 2 hours to oligomerize. 385 kg of diphenyl ether is added to this oligomer,
An azeotropic dehydration reaction of 5 mmHg was performed, and the distilled water and the solvent were separated by a water separator, and only the solvent was returned to the reactor. Two hours later, the organic solvent to be returned to the reactor was passed through a column filled with 50 kg of molecular sheep 3A, and then returned to the reactor. The reaction was carried out at 130 ° C./17 mmHg for 15 hours, and the weight average molecular weight (Mw) was obtained. 14,000 polybutylene succinate (hereinafter abbreviated as PSB-1) solution was obtained. After 180 kg of dehydrated diphenyl ether was added to this solution for dilution, the solution was cooled to 40 ° C., and the precipitated crystals were filtered. To this powder were added 200 kg of 0.5 N HCl and 200 kg of ethanol, and the mixture was stirred at 25 ° C. for 1 hour, filtered, dried at 60 ° C./50 mmHg, and dried with PSB-19.
1.5 kg (94.8% yield) were obtained. This PSB-1
Had a weight average molecular weight (Mw) of 138,000.

Examples 1 to 7 Production Examples 1 to 3 were used as aliphatic polyester (a1) components.
As the aliphatic polyester (a2) component, polybutylene succinate (PSB-1) or Bionore # 3001 (PSB-
2) was mixed with a plasticizer and an inorganic additive at a ratio shown in Table 1 [Table 1] using a Henschel mixer, and then pelletized under the conditions of an extruder cylinder set temperature of 160 to 210 ° C.
After drying the pellet at 60 ° C. for 10 hours,
With an inflation molding machine (die diameter 40 mm)
It was formed at a temperature of 160 to 170 ° C., and a 30 μm thick blown film having a folding diameter of 150 mm was formed and wound up. About the obtained film, flexibility, heat resistance, mold resistance, and biodegradability were measured. The results are shown in Table 1 [Table 1].
Shown in

Comparative Examples 1 to 12 A mixture of the polylactic acid obtained in Production Examples 1 to 3 and polybutylene succinate (PSB-1) or Bionole # 3001 (PSB-2) manufactured by Showa Polymer Co., Ltd. was added to a plasticizer. After mixing the inorganic additives in the proportions shown in Tables 2 and 3 with a Henschel mixer, an inflation film was prepared in the same manner as in the example, and various measurements were performed on the obtained film.
The results are shown in Table 2 [Table 2] and Table 3 [Table 3].

[0051]

[Table 1] [Legend of Table-1] PSB: Polybutylene succinate • PSB-1: Polybutylene succinate shown in Production Example-3 • PSB-2: Bionore # 3001 (manufactured by Showa Kogyo KK) ATBC: acetyl tributyl citrate TEDA: triethylene glycol diacetate TRAC: triacetin DBS: dibutyl sebacate

[0052]

[Table 2] [Legend of Table-2] PSB ··· Polybutylene succinate · PSB-1 ··· Polybutylene succinate shown in Production Example-3 · PSB-2 ··· Bionore # 3001 (manufactured by Showa Polymer Co., Ltd.) Plasticizer ATBC: acetyl tributyl citric acid

[0053]

[Table 3] [Legend of Table-3] * ... poor dispersion ND ... no data PSB-2 ... Bionore # 3001 (manufactured by Showa Polymer Co., Ltd.) Plasticizer LP ... liquid paraffin DOF ... dioctyl phthalate TOTM ... trimellitic acid SE ... ethyl stearate EDO ... epoxidized soybean oil PTB ... tributyl phosphate

[0054]

The polylactic acid-based resin composition according to the present invention comprises:
It is a composition having flexibility and heat resistance while maintaining easy decomposability and mold resistance in the compost of polylactic acid, and a composition suitable for T-die molding and inflation molding. The film / sheet according to the present invention has a high temperature (80
(° C), there is no bleeding of the plasticizer and no blocking of the film / sheet, and it has excellent practical heat resistance.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI // C08J 5/00 CFJ C08J 5/00 CFJ B29K 67:00 B29L 7:00 (72) Inventor Hisashi Aihara Sakae-ku, Yokohama-shi, Kanagawa 1190 Kasama-cho Mitsui Chemical Co., Ltd. (72) Inventor Tomoyuki Nakata 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Prefecture Inside Mitsui Chemical Co., Ltd. (72) Inventor Masanobu Amioka 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Mitsui Chemicals, Inc.

Claims (9)

[Claims] A polylactic acid (a1) having a melting point of 80 to 25.
A polylactic acid-based resin composition comprising a polymer component (A) containing an aliphatic polyester (a2) having biodegradability at 0 ° C. and a plasticizer (B) having biodegradability. Polylactic acid (a1) and the aliphatic polyester (a2)
The polylactic acid (a1) was 90% based on the total weight of
To 50% by weight, and the aliphatic polyester (a2)
And the composition ratio of the plasticizer (B) is equivalent to 5 to 25 parts by weight of the plasticizer (B) based on 100 parts by weight of the polymer component (A). A polylactic acid resin composition having both flexibility and heat resistance. 2. The polylactic acid-based resin composition according to claim 1, wherein the aliphatic polyester (a2) is polybutylene succinate. 3. The plasticizer according to claim 1, wherein the plasticizer (B) is at least one selected from the group consisting of aliphatic polybasic acid esters, aliphatic polyhydric alcohol esters, and oxyacid esters. A polylactic acid-based resin composition having both flexibility and heat resistance. 4. The plasticizer according to claim 1, wherein the plasticizer (B) is at least one selected from the group consisting of acetyltributylcitrate, triacetin, dibutylsebacate, and triethylene glycol diacetate. A polylactic acid-based resin composition having both heat resistance and heat resistance. 5. The softness and the elastic modulus are from 2000 to 100.
^2. It is equivalent to 00 kgf / cm ^2.
5. The polylactic acid-based resin composition according to any one of items 1 to 4, characterized by having both flexibility and heat resistance. 6. The heat resistance is 60 to 120 ° C.
The polylactic acid-based resin composition according to any one of claims 1 to 5, wherein the composition has both flexibility and heat resistance. 7. A molded product comprising the polylactic acid-based resin composition according to claim 1, which has both flexibility and heat resistance. 8. A film having a thickness of 5 to 1000 μm, comprising a polylactic acid-based resin composition having both flexibility and heat resistance according to any one of claims 1 to 6.
Or a sheet. 9. An inflation film and / or inflation sheet having a thickness of 5 to 1000 μm, comprising a polylactic acid-based resin composition having both flexibility and heat resistance according to any one of claims 1 to 6. .