JP3514736B2 - Resin composition, molded article and method for producing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a resin composition of a lactic acid resin, a molded product and a method for producing the same.

[0002]

2. Description of the Related Art Conventional plastics are stable in the natural environment for a long time, and when discarded in the natural environment,
It has been pointed out that problems such as spoiling the natural landscape and the living environment of wild animals and plants, and promoting the shortening of the life of landfills for wastes due to their low bulk specific gravity even when they are buried in the soil. In recent years, from the viewpoint of environmental protection, even if plastic products are dumped, they are finally required to be decomposed and disappear so as not to adversely affect the natural environment. It is known that biodegradable plastics gradually disintegrate / decompose in soil or in water due to hydrolysis or biodegradation, and finally become harmless decomposition products by the action of microorganisms. Examples of biodegradable plastics that have been put into practical use include aliphatic polyesters, modified polyvinyl alcohol (PVA), cellulose ester compounds, starch modified products, and blends thereof. Each of these biodegradable plastics has its own characteristics,
Applications can be expanded accordingly, but lactic acid-based resin, which is one of the aliphatic polyesters, is superior to other biodegradable plastics in transparency, rigidity, heat resistance, processability, etc. Therefore, hard polyvinyl chloride (PV
C), polystyrene, polyethylene terephthalate (P
Attention has been paid as a substitute material for ET). However, although a molded product obtained by injection molding a lactic acid resin is excellent in rigidity, it is poor in heat resistance, impact resistance and wet heat durability,
It could not be used as a container for food containers or home appliances. Much research has been done to improve these drawbacks of lactic acid based resins. For example, Tokuyohei 4-504
No. 731, Japanese Patent Publication No. 6-504799, Japanese Patent Laid-Open No. 4-220456, Japanese Patent Laid-Open No. 8-193165, Japanese Laid-Open Patent Publication No. 10-87976, etc., are mainly formed by promoting crystallization. It is described to improve the heat resistance and impact resistance of the body. However, it has not yet been possible to improve the wet heat durability, which is a major drawback of the lactic acid-based resin molded product, which is in line with heat resistance and impact resistance. Therefore, for example, when the resin is left in a parked car in the middle of summer or in a container of a freighter passing near the equator, the resin may have a reduced molecular weight, which may cause a problem in the molded body.

[0003]

That is, the present invention has been made to solve the above-mentioned problems, and an object of the present invention is to hardly impair the biodegradability inherent to lactic acid resins. Another object of the present invention is to provide a molded product of a lactic acid-based resin having excellent heat resistance, impact resistance and wet heat resistance, and a method for producing the same.

[0004]

The present inventors have completed the present invention as a result of earnest studies in view of the present situation. That is, the molded product of the present invention contains 50 to 9 lactic acid-based resins in which the mass ratio of L-lactic acid and D-lactic acid is 100: 0 to 90:10, or 0: 100 to 10:90.
A composition comprising 5% by mass and 5 to 50% by mass of an aliphatic polyester resin having a glass transition temperature (Tg) of 0 ° C. or less,
And, based on 100 parts by mass of the composition, 0.1 to 10 parts by mass of a hydrolysis inhibitor as a main component , and
Anti-solvent agents are layered silicates, olefinic resins and calcium
At least one selected from the group consisting of bodiimide compounds
It is characterized by being one. Here, the melting point of the aliphatic polyester may be 65 to 99 ° C. Also, the relative crystallinity of the lactic acid-based resin may be 50 to 100%. The resin composition of the present invention comprises 50 to 95 lactic acid-based resins having a mass ratio of L-lactic acid and D-lactic acid of 100: 0 to 90:10 or 0: 100 to 10:90.
%, And a composition comprising 5 to 50% by mass of an aliphatic polyester resin having a glass transition temperature (Tg) of 0 ° C. or less, and 0.1 to 10 parts by mass of water based on 100 parts by mass of the composition. The main component is a decomposition inhibitor , and the hydrolysis
Inhibitors include layered silicates, olefinic resins and carbohydrates.
At least one selected from the group consisting of diimide compounds
And characterized in that. In the method for producing a molded article of the present invention, the mass ratio of L-lactic acid and D-lactic acid is 100: 0-9.
A composition comprising 50 to 95% by mass of a lactic acid-based resin of 0:10 or 0: 100 to 10:90 and 5 to 50% by mass of an aliphatic polyester resin having a glass transition temperature (Tg) of 0 ° C. or lower. , And 100 parts by mass of the composition,
0.1 to 10 parts by mass of hydrolysis inhibitor as a main component ,
, The hydrolysis inhibitor is a layered silicate, olefin
Selected from the group consisting of resins and carbodiimide compounds
It is characterized in that it is formed by molding by using any one of injection molding, blow molding, sheet thermoforming or press molding, using at least one resin composition.
Here, the temperature of the mold used for forming the molded body is preferably 61 to 84 ° C.

DETAILED DESCRIPTION OF THE INVENTION The present invention is described in detail below. The molded product of the present invention has a mass ratio of L-lactic acid and D-lactic acid of 10 or less.
50 to 95% by mass of lactic acid-based resin having 0: 0 to 90:10, or 0: 100 to 10:90, and 5 to 5 of aliphatic polyester resin having a glass transition temperature (Tg) of 0 ° C. or less.
0.1 to 10 parts by mass of a hydrolysis inhibitor is contained as a main component based on 100 parts by mass of the composition consisting of 0% by mass.

The lactic acid-based resin used in the present invention means poly (L-lactic acid) whose structural unit is L-lactic acid, poly (D-lactic acid) whose structural unit is D-lactic acid, and structural unit L.
-Lactic acid and D-lactic acid, which means poly (DL-lactic acid) or a mixture thereof. The composition of the lactic acid-based resin needs to be D-lactic acid: L-lactic acid = 100: 0 to 90:10 or 0: 100 to 10:90, and D-lactic acid: L-lactic acid = It is preferably in the range of 100: 0 to 94: 6 or in the range of 0: 100 to 6:94. It is also possible to blend two or more kinds of lactic acid-based resins having different composition ratios of D-lactic acid and L-lactic acid.
If the ratio of D-lactic acid to L-lactic acid is outside the range of 100: 0 to 90:10 or 0: 100 to 10:90, it is difficult to obtain the desired heat resistance. A lactic acid resin containing only D-lactic acid or L-lactic acid becomes a crystalline resin, has a high melting point, and tends to have excellent heat resistance and mechanical properties.

As the method for polymerizing the lactic acid-based resin, known methods such as condensation polymerization method and ring-opening polymerization method can be adopted.
For example, in the condensation polymerization method, L-lactic acid or D-lactic acid, or a mixture thereof or the like can be directly subjected to dehydration condensation polymerization to obtain a lactic acid-based resin having an arbitrary composition. Further, in the ring-opening polymerization method (lactide method), lactide, which is a cyclic dimer of lactic acid, is used, if necessary, while using a polymerization regulator or the like.
A lactic acid resin can be obtained using a suitable catalyst.
Incidentally, lactide includes L-lactide which is a dimer of L-lactic acid, D-lactide which is a dimer of D-lactic acid, and DL-lactide which is a dimer of D-lactic acid and L-lactic acid. By mixing these as necessary and polymerizing, polylactic acid having any composition and crystallinity can be obtained.

In the present invention, it may be a copolymer with another hydroxycarboxylic acid unit such as α-hydroxycarboxylic acid or an aliphatic diol / aliphatic dicarboxylic acid. Other hydroxycarboxylic acid units copolymerized with the lactic acid-based resin include optical isomers of lactic acid (D-lactic acid for L-lactic acid and L-lactic acid for D-lactic acid).
-Lactic acid), glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 2-hydroxy-n-butyric acid, 2-hydroxy-3,3-dimethylbutyric acid, 2-hydroxy-3-methylbutyric acid, 2-methyllactic acid, Examples thereof include bifunctional aliphatic hydroxycarboxylic acids such as 2-hydroxycaproic acid and lactones such as caprolactone, butyrolactone and valerolactone. Examples of the above aliphatic diol copolymerized with the lactic acid resin include ethylene glycol, 1,4-butanediol, 1,4-cyclohexanedimethanol and the like. Examples of the aliphatic dicarboxylic acid include succinic acid, adipic acid, suberic acid, sebacic acid and dodecanedioic acid.

In the present invention, a non-aliphatic dicarboxylic acid such as terephthalic acid and /
Alternatively, a non-aliphatic diol such as an ethylene oxide adduct of bisphenol A may be used. Furthermore, a small amount of a chain extender such as a diisocyanate compound, an epoxy compound or an acid anhydride may be used for the purpose of increasing the molecular weight.

The lactic acid resin used in the present invention is
The weight average molecular weight is preferably 50,000 to 400,000,
More preferably, it is 100,000-250,000. When the molecular weight is less than 50,000, practical physical properties such as mechanical properties and heat resistance may not be exhibited, and when the molecular weight is more than 400,000, the melt viscosity may be too high and molding processability may be poor.

In the present invention, a lactic acid-based resin is mixed with an aliphatic polyester resin having a glass transition temperature (Tg) of 0 ° C. or lower, more preferably −20 ° C. or lower, to give a molded article excellent impact resistance. Can be given.
Glass transition temperature (Tg) of aliphatic polyester resin is 0
If the temperature exceeds ℃, the effect of improving impact resistance becomes poor.

Such an aliphatic polyester resin is an aliphatic polyester resin excluding lactic acid-based resins, for example, an aliphatic polyester obtained by condensing an aliphatic diol and an aliphatic dicarboxylic acid, or a ring-opening polymerization of a cyclic lactone. Examples thereof include aliphatic polyester and synthetic aliphatic polyester. The aliphatic polyester obtained by condensing the aliphatic diol and the aliphatic dicarboxylic acid is an aliphatic diol such as ethylene glycol, 1,4-butanediol, and 1,4-cyclohexanedimethanol, and the aliphatic dicarboxylic acid. It can be obtained by condensation polymerization of one or more selected from succinic acid, adipic acid, suberic acid, sebacic acid, dodecanedioic acid and the like. If desired, a desired polymer can be obtained by jumping up with an isocyanate compound or the like. Typical examples of the aliphatic polyester obtained by ring-opening polymerization of cyclic lactones include ε-caprolactone, δ-valerolactone, β-methyl-δ-valerolactone, which are cyclic monomers, and one or more selected from these. Are polymerized. Examples of synthetic aliphatic polyesters include cyclic acid anhydrides and oxiranes, for example, copolymers of succinic anhydride and ethylene oxide, propylene oxide and the like.

The glass transition temperature (T
g) the aliphatic polyester resin having a temperature of 0 ° C or lower has a melting point of 6
It is preferably 5 to 99 ° C. If the melting point is lower than 65 ° C, the molded product may adhere to the mold during molding and the release may not be successful, and the molded product may not be taken out, or the heat resistance of the lactic acid resin itself may be exhibited. However, the aliphatic polyester component may elute in a high temperature atmosphere of, for example, 60 ° C., and the surface appearance may be impaired or deformed. If the melting point is higher than 99 ° C, the aliphatic polyester itself tends to be brittle, and it may be difficult to improve the impact resistance of the molded product.

In the present invention, the weight ratio of L-lactic acid to D-lactic acid is 100: 0 to 90:10, or 0: 100.
Lactic acid resin of 10 to 90: 50 to 95% by mass,
It is important to mix the aliphatic polyester resin having a glass transition temperature (Tg) of 0 ° C. or less at a ratio of 5 to 50% by mass. When the lactic acid-based resin is less than the above range, the rigidity of the molded product is lowered, and the molded product is crushed by external pressure and is easily scratched, and further, heat resistance and wet heat durability are impaired.
Further, if the proportion of the lactic acid resin exceeds the above range, practical impact resistance cannot be exhibited.

In the present invention, with respect to 100 parts by mass of a composition comprising a lactic acid resin and an aliphatic polyester resin,
It is necessary to add the hydrolysis inhibitor within the range of 0.1 to 10 parts by mass. In the present invention, at least one kind selected from the group consisting of surface-treated inorganic filler, layered silicate, hydrophobic wax, hydrophobic plasticizer, olefin resin and carbodiimide compound is selected as the hydrolysis inhibitor.

In the present invention, the surface-treated inorganic filler refers to silica, talc, kaolin, clay, alumina, non-swelling mica, calcium carbonate, calcium sulfate, magnesium carbonate, diatomaceous earth, asbestos, glass fiber, metal powder, etc. In order to increase the hydrophobicity of the surface, it was surface-treated with higher fatty acid, higher fatty acid salt, higher fatty acid amide, higher fatty acid ester, higher fatty alcohol, higher fatty alcohol ester, organic silane coupling agent, organic titanium coupling agent, etc. Refers to something. If the surface treatment is not applied to the inorganic filler, it is difficult to improve the wet heat durability of the molded product, and the wet heat durability may be lowered. In order to improve the wet heat durability of the molded body, it is preferable to perform the surface treatment using a higher fatty acid, a higher fatty alcohol, or a derivative thereof having a total carbon number of 12 or more. As the organic silane coupling agent and the organic titanium coupling agent, those containing an alkyl group or a phenyl group are preferably used.

The layered silicate used in the present invention is formed by stacking an octahedral sheet containing an element selected from aluminum, magnesium, lithium, etc., on top and bottom of a silicic acid tetrahedral sheet to form a single plate crystal layer. Those having a 2: 1 type structure and having exchangeable cations between the plate crystal layers are preferably selected. The size of the single plate crystal layer is usually 0.05 to 0.5 μm in width and 6 to 15 Å in thickness. The cation exchange capacity of the exchangeable cation is 0.2 to 3 meq / g, and preferably the cation exchange capacity is 0.8 to 1.5 me.
q / g. Specific examples of the layered silicate preferably used in the present invention include smectite clay minerals such as montmorillonite, beidellite, nontronite, saponite, hectorite, and sauconite, vermiculite, halloysite, kanemite, kenyaite, zirconium phosphate, and titanium phosphate. Various clay minerals, Li type fluorine teniolite, Na type fluorine teniolite, Na
Examples thereof include swelling mica such as type 4 silicon-fluorine mica and Li-type tetrasilicon-fluorine mica, which may be natural or synthetic. Among these, smectite clay minerals such as montmorillonite and hectorite, and swelling synthetic mica such as Na-type tetrasilicon fluorine mica and Li-type fluorine teniolite are preferable.

In the present invention, it is preferable that the exchangeable cations existing between the layers are layered silicates exchanged with organic onium ions. As an organic onium ion,
Examples thereof include ammonium ion, phosphonium ion, and sulfonium ion. Among these, ammonium ion and phosphonium ion are preferable, and ammonium ion is particularly preferably used. The ammonium ion may be any of primary ammonium, secondary ammonium, tertiary ammonium, and quaternary ammonium. Examples of primary ammonium ions include decyl ammonium, dodecyl ammonium, octadecyl ammonium, oleyl ammonium, and benzyl ammonium. Examples of the secondary ammonium ion include methyldodecyl ammonium and methyl octadecyl ammonium. Examples of the tertiary ammonium ion include dimethyldodecyl ammonium and dimethyl octadecyl ammonium. Quaternary ammonium ions include benzyltrimethylammonium, benzyltriethylammonium, benzyltributylammonium,
Benzyl dimethyl dodecyl ammonium, benzyl trialkyl ammonium ion such as benzyl dimethyl octadecyl ammonium, trioctyl methyl ammonium, alkyl trimethyl ammonium ion such as trimethyl octyl ammonium, trimethyl dodecyl ammonium, trimethyl octadecyl ammonium, dimethyl dioctyl ammonium, dimethyl didodecyl ammonium, dimethyl Examples thereof include dimethyldialkylammonium ions such as dioctadecyl ammonium. In addition to these, it is derived from aniline, p-phenylenediamine, α-naphthylamine, p-aminodimethylaniline, benzidine, pyridine, piperidine, 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid and the like. And ammonium ion. Among these ammonium ions, trioctylmethylammonium, trimethyloctadecylammonium, benzyldimethyldodecylammonium, benzyldimethyloctadecylammonium, octadecylammonium, and ammonium derived from 12-aminododecanoic acid are preferably used.

Hydrophobic waxes include 1) hydrocarbon waxes such as liquid paraffin, natural paraffin, synthetic paraffin, microcrystalline wax, polyethylene wax and fluorocarbon wax, 2) fatty acid waxes such as higher fatty acids and oxyfatty acids, 3) ) Aliphatic amide waxes such as aliphatic amides and alkylenebisfatty acid amides, 4) fatty acid lower alcohol esters, fatty acid polyhydric alcohol ester waxes, ester waxes such as fatty acid polyglycol esters, 5) fatty alcohols, polyhydric alcohols, Examples include alcohol waxes such as polyglycerol, 6) metal soaps, and 7) mixed systems thereof. Here, 1) hydrocarbon waxes include liquid paraffin and microcrystalline wax, 2) fatty acid waxes include stearic acid and lauric acid, and 3) aliphatic amide waxes include stearamide and palmitin. Acid amides, oleic acid amides, erucic acid amides, methylene bis stearyl amides, ethylene bis stearyl amides are 4) Ester waxes are butyl stearate, hydrogenated castor oil, ethylene glycol monostearate 5) Alcohol As the wax, cetyl alcohol and stearyl alcohol are preferably used, and as the 6) metal soap, aluminum stearate and calcium stearate are preferably used in terms of effect and cost.

As the hydrophobic plasticizer, the following (1) to
It is preferable that at least one kind is selected from the compounds shown in (8). _{(1) H 5 C 3 (} OH) 3-n (OOCCH 3) n
However, 0 <n ≦ 3 This is a mono- of glycerin,
Alternatively, di- or triacetate may be used, and a mixture thereof may be used, but n is preferably close to 3. (2) Glycerin alkylate (alkyl group has 2 carbon atoms
-20, there may be a hydroxyl group residue), for example, glycerin tripropionate and glycerin tributyrate. (3) It is an ethylene glycol alkylate (the alkyl group may have 1 to 20 carbon atoms and a hydroxyl group residue may be present), and is, for example, ethylene glycol diacetate. (4) A polyethylene glycol alkylate having an ethylene repeating unit of 5 or less (the alkyl group has 1 to 2 carbon atoms).
0, a hydroxyl group residue may be present), and examples thereof include diethylene glycol monoacetate and diethylene glycol diacetate. (5) An aliphatic monocarboxylic acid alkyl ester (wherein the alkyl group has 1 to 20 carbon atoms), for example, butyl stearate. (6) Aliphatic dicarboxylic acid alkyl ester (wherein the alkyl group has 1 to 20 carbon atoms and may have a residue of a carboxyl group), and examples thereof include di (2-ethylhexyl) adipate and di (2-ethylhexyl) azelate. Is. (7) Aliphatic tricarboxylic acid alkyl ester (wherein the alkyl group has 1 to 20 carbon atoms and may have a residue of a carboxyl group), for example, citric acid trimethyl ester. (8) A low molecular weight aliphatic polyester having a weight average molecular weight of 20,000 or less, such as succinic acid and an ethylene glycol / propylene glycol condensate (Dainippon Ink and Chemicals, Inc.)
It is sold under the trade name of Polysizer). (9) Natural fats and oils and their derivatives, for example,
Soybean oil, epoxidized soybean oil, castor oil, tung oil, rapeseed oil.

As the olefin resin, mainly polyethylene and polypropylene, and their derivatives and copolymers can be widely used. For example, LDPE (low density polyethylene), LLDPE (linear low density polyethylene), VLDPE (ultra low density polyethylene), EVA
(Ethylene vinyl acetate copolymer), EVOH (Ethylene vinyl alcohol copolymer), Metallocene resin, PP
(Polypropylene), IO (ionomer), EAA
(Ethylene acrylic acid copolymer), EMMA (ethylene methyl methacrylate copolymer), EMA (ethylene methyl acrylate copolymer), EEA (ethylene ethyl acrylate copolymer), adhesive polyolefin resin and the like. Considering dispersibility with a lactic acid-based resin, a resin having a small amount of polar functional groups such as EVA and IO is preferable to a homopolymer.

Examples of the carbodiimide compound include compounds having at least one carbodiimide group in the molecule. These carbodiimide compounds may be aliphatic, alicyclic or aromatic. For example, poly (4,4′-diphenylmethanecarbodiimide), poly (p-phenylenecarbodiimide), poly (m-phenylenecarbodiimide), poly (tolylcarbodiimide), poly (diisopropylphenylenecarbodiimide), poly (methyl-diisopropylphenylenecarbodiimide) , Poly (triisopropylphenylenecarbodiimide), and the like. The carbodiimide compound is
They may be used alone or in combination of two or more.

The hydrolysis inhibitor (C) is added in a total amount of the lactic acid resin (A) and the aliphatic polyester resin (B) of 1
If it is less than 0.1 parts by mass with respect to 00 parts by mass, wet heat durability will not be exhibited, and if it exceeds 10 parts by mass, problems such as deterioration in workability and physical properties of the molded body will occur. Excessive addition of surface-treated inorganic fillers, layered silicic acid compounds and olefinic resins causes impact resistance deterioration and poor appearance, while excessive addition of hydrophobic waxes, hydrophobic plasticizers and carbodiimide compounds decreases viscosity. Causes deterioration of molding processability, deterioration of mechanical strength, bleeding on the surface of a molded product, and stickiness.

Further, within a range that does not impair the effects of the present invention,
Additives such as heat stabilizers, antioxidants, UV absorbers, light stabilizers, pigments, colorants, lubricants, nucleating agents and the like can be formulated.

Next, a method of manufacturing the molded body will be described. In the present invention, the molding method is selected from injection molding, blow molding, sheet thermoforming, press molding and the like. However, in the present invention, the relative crystallinity of the lactic acid resin is 50
It is preferably within the range of 100%. When the relative crystallinity of the lactic acid-based resin is lower than 50%, the heat resistance and wet heat resistance of the molded product are difficult to be exhibited. Therefore, in the present invention, it is preferable to adjust the resin composition, the resin temperature, the mold temperature, the cooling conditions and the like (particularly the mold temperature) so that the relative crystallinity of the lactic acid resin is within such a range. In the present invention, the relative crystallinity is calculated by the following formula.

## EQU1 ## Relative crystallinity (%) = (ΔHm-ΔHc) / Δ
Hm × 100 ΔHm: heat of fusion of lactic acid-based resin ΔHc: heat of crystallization of lactic acid-based resin The relative crystallinity varies depending on the DL ratio of the lactic acid-based resin, the type of resin composition, addition of a nucleating agent, etc. Generally, the slower the cooling rate, the higher the relative crystallinity. In the present invention, the mold temperature is preferably 61 to 84 ° C. in any molding method in order to balance the relative crystallinity and the moldability. If the temperature of the mold is lower than 61 ° C., the crystallization rate is slow and it takes too long to obtain a desired relative crystallinity. If it is higher than 84 ° C., the crystallization rate is high, but the molded body is hard to mold. Adhesion is likely to occur, the molding cycle may not be improved, and the molded body may be deformed when taken out from the mold. The contact time with the mold is 1 to 1000 seconds,
It is preferably adjusted within the range of 10 to 100 seconds. In addition,
In order to increase the crystallization speed, it is effective to add a nucleating agent such as talc, silica, rice wax, and phthalic acid ester, but any of the above-mentioned hydrolysis inhibitors is not a little crystallization nucleating agent. Also has the effect of. Therefore, depending on the type and amount of the hydrolysis inhibitor added, the relative crystallinity may fall within a predetermined range even if the mold temperature is lower.

The molded article of the present invention can be formed by any one of the above-mentioned molding methods. For example, in injection molding, the resin composition of the present invention is melted and softened and then filled in a mold. A molded product can be formed by a predetermined molding cycle, and in extrusion molding, the resin composition according to the present invention can be charged into, for example, a T-die extruder or the like for molding. Further, in vacuum molding, for example, a film or sheet formed by extrusion molding is used as a preform, and this is heated and softened, and then a vacuum forming machine is used.
It can be vacuum formed in the mold. In each molding method, the equipment used and general processing conditions are
It is not particularly limited.

Specifically, a method of directly mixing a lactic acid resin, an aliphatic polyester resin and a hydrolysis inhibitor and molding them by using an extruder, or after homogeneously compounding with an extruder having a kneading capacity in advance, for example, Examples thereof include a method of forming a compound pellet and molding using the compound pellet, a method of forming a sheet from the compound pellet and molding the sheet.

[0028]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto. In addition, the measured values shown in the examples are measured and calculated under the following conditions. (1) Moldability The adhesiveness to the mold when the molded product was taken out from the mold was evaluated in three stages according to the criteria shown below. ○ There was no adhesion to the mold and it could be taken out without resistance, and there was no deformation. △ There was slight adhesion or deformation to the mold, but there was no problem in practical use. × Adhesion to the mold occurred and it was taken out. A load was required and the load was applied, which caused a clear deformation of the compact. (2) Relative crystallinity The compact was carved into scales with a diameter of 5 mm and a weight of about 10 mg, and differential scanning was performed. Using a calorimeter (manufactured by Perkin Elmer, trade name "DSC-7"), temperature rise measurement (differential scanning calorimetry) was performed based on JIS-K7121, and calculated by the following formula.

## EQU2 ## Relative crystallinity (%) = (ΔHm-ΔHc) / Δ
Hm × 100 ΔHm: Heat of fusion of lactic acid-based resin ΔHC: Heat of crystallization of lactic acid-based resin (3) Impact resistance (Izod impact test) A molded body was directly formed into a width of 10 mm × a length of 80 mm × a thickness of 4 mm. A universal impact tester manufactured by Yasuda Seiki Seisakusho Ltd. (Model No. 258) is molded or a sample of this size is cut out from the obtained molded body and based on JIS-K7111.
Was subjected to an Izod impact test with a notch (notch type A) and edgewise. The unit is KJ / m ² . (4) The heat resistant molded body was allowed to stand in a hot air oven at 100 ° C. for 30 minutes, and then visually evaluated. The evaluation criteria are shown by the symbol “◯” when no deformation was visually observed, “Δ” when slightly deformed, and by “x” when apparently deformed. (5) Weight average molecular weight of lactic acid-based resin To gel permeation chromatography HLC-8120GPC manufactured by Tosoh Corporation, and GPC-chromatographic column Shim-Pack series manufactured by Shimadzu Corporation-
Equipped with 800CP, chloroform as the solvent,
Solution concentration 0.2wt / vol%, solution injection amount 200μ
1, the solvent flow rate was 1.0 ml / min, the solvent temperature was 40 ° C., and the weight average molecular weight of the lactic acid resin was calculated in terms of polystyrene. However, the standard polystyrene used had a weight average molecular weight of 2,000,000, 670,000, 11
30,000, 35,000, 10,000, 4,000
It is 0,600. (6) Wet-heat durability (molecular weight retention rate) The weight of the lactic acid-based resin after allowing the molded body to stand for 30 hours in a constant temperature and humidity machine LH-112 manufactured by Tabai Espec, which is adjusted to a temperature of 85 ° C. and a humidity of 85%. The average molecular weight was measured. The molecular weight retention (%) was calculated from the weight average molecular weight of the lactic acid resin before and after being placed in a thermo-hygrostat by the following formula, and evaluated based on the criteria shown below.

[Equation 3] Molecular weight retention rate (%) = (molecular weight after test / molecular weight before test) × 100 ○ Molecular weight retention rate of 75 to 100% △ Molecular weight retention rate of 50 to 74% × molecular weight retention rate Of 0 to 49%

Reference Example 1 L-lactic acid: D-lactic acid = 99: 1 lactic acid resin (A)
(Cargill Dow, product name "NatureWork"
s4031D ", weight average molecular weight 200,000), and glass transition temperature (Tg) as aliphatic polyester resin (B)
Is -45 ° C, polybutylene succinate adipate (manufactured by Showa Highpolymer Co., Ltd., trade name "Bionore 300
3 ") and octylsilane-treated silica (manufactured by Nippon Aerosil Co., Ltd., trade name" R805 ") as a hydrolysis inhibitor (C) with respect to 100 parts by mass of a composition blended in a mass ratio of 80:20. 8 parts by mass were blended, and this was blended with a Mitsubishi Heavy Industries, Ltd. small-sized same-direction twin-screw extruder for 200
A raw material pellet was prepared by compounding at ℃. The raw material pellets thus obtained are compact injection molding machine "PS40E5" manufactured by NISSEI PLASTIC INDUSTRIES CO., LTD.
"A", cylinder temperature 200 ℃, mold temperature 80
Injection molding was performed at a temperature of 60 ° C. for 60 seconds to obtain a molded body. The obtained molded body was evaluated for moldability, impact resistance, heat resistance, and wet heat durability. In addition, the obtained results were comprehensively evaluated, and when all of them were excellent, they were shown as “◯”, when they were above the practical level, as “Δ”, and when they were not practical, as “x”. These results are shown in Table 1.
Shown in.

[0030] In Comparative Example 1 Reference Example 1, except for not using an anti-hydrolyzing agent to produce a molded body in the same manner as in Reference Example 1. The same evaluation as in Reference Example 1 was performed on the obtained molded body. The results are shown in Table 1. [0031] (Examples 2, 4, 5, Reference Example 3 ) In Reference Example 1, except that the type and addition amount (unit is parts by mass) of the hydrolysis inhibitor (C) are changed as shown in Table 1. A molded body was produced in the same manner as in Reference Example 1. The same evaluation as in Reference Example 1 was performed on the obtained molded body. The results are shown in Table 1.

(Examples 2 to 5) In Example 1, the kind and addition amount of the hydrolysis inhibitor (C) (unit is parts by mass)
A molded body was produced in the same manner as in Example 1 except that the value was changed as shown in Table 1. The same evaluation as in Example 1 was performed on the obtained molded body. The results are shown in Table 1.

[0032] (Comparative Example 2-3) Reference Example 3, Reference Example except the addition amount of the (in parts by weight) was changed as shown in Table 1 of the hydrolysis inhibitor (C)
A molded body was produced in the same manner as in 3 . The same evaluation as in Reference Example 1 was performed on the obtained molded body. The results are shown in Table 1.
Shown in. It was confirmed that the molded body of Comparative Example 3 had bleeding.

[0033]

[Table 1]

(Example 6) L-lactic acid: D-lactic acid = 95: 5 lactic acid resin (A)
(Cargill Dow, product name "NatureWork"
s4050D ", weight average molecular weight 200,000), and glass transition temperature (Tg) as aliphatic polyester resin (B)
Is -45 ° C. and polybutylene succinate adipate (manufactured by Showa High Polymer Co., Ltd., trade name “Bionore 3003”) is blended in a mass ratio of 90:10.
Octylsilane-treated silica (manufactured by Nippon Aerosil Co., Ltd., trade name "R8"
05 ") was blended in an amount of 1.5 parts by mass, and this was compounded at 200 ° C. using a small-sized same-direction twin-screw extruder manufactured by Mitsubishi Heavy Industries, Ltd. to prepare raw material pellets. The obtained raw material pellets were put into a small injection molding machine "PS40E5A" manufactured by Nissei Plastic Co., Ltd. equipped with a mold having an Izod test piece shape, and the cylinder temperature was 200 ° C, the mold temperature was 110 ° C, and the molding cycle was 30 seconds. Injection molding was performed to obtain a molded body. The same evaluation as in Reference Example 1 was performed on the obtained molded body. The results are shown in Table 1.

Example 7 In Example 6, the aliphatic polyester resin (B) was changed to polybutylene succinate (manufactured by Showa Highpolymer Co., Ltd., trade name "Bionore 1003"), and the mold was used as a molding condition. A molded body was produced in the same manner as in Example 6 except that the temperature was changed to 84 ° C and the molding cycle was changed to 200 seconds. The same evaluation as in Reference Example 1 was performed on the obtained molded body. The results are shown in Table 2.

(Example 8) Example 7 was repeated except that the aliphatic polyester resin (B) was changed to polycaprolactone (manufactured by Daicel Chemical Industries, Ltd., trade name "Placcel H-7"). A molded body was prepared in the same manner. About the obtained molded body,
The same evaluation as in Reference Example 1 was performed. The results are shown in Table 2.

Comparative Example 4 Example 7 was repeated except that the aliphatic polyester resin (B) was changed to a polyhydroxybutyric acid / valeric acid copolymer (manufactured by Zeneca, trade name "Biopol"). A molded body was produced in the same manner as in. The resulting molded body, ginseng
It was evaluated in the same manner as in Example 1 considered. The results are shown in Table 2.

Comparative Example 5 In Example 6, the lactic acid resin (A) was mixed with L-lactic acid: D-
Lactic acid = 88:12 lactic acid resin (made by Cargill Dow,
Product name "NatureWorks4060D", weight average molecular weight 200,000) was changed, compounding ratio of lactic acid resin (A) and aliphatic polyester resin (B) was changed as shown in Table 2, and molding conditions were mold temperature 84. ℃, molding cycle 20
A molded product was produced in the same manner as in Example 6 except that the time was changed to 0 second. The same evaluation as in Reference Example 1 was performed on the obtained molded body. The results are shown in Table 2.

(Examples 9 to 10 and Comparative Example 6) In Example 6, the type of the lactic acid resin (A) was changed to Reference Example 1
Lactic acid resin similar to the above (manufactured by Cargill Dow, product name "N
NatureWorks 4031D ", weight average molecular weight 2
100,000), the compounding ratio of the lactic acid resin (A) and the aliphatic polyester resin (B) was changed as shown in Table 2, and the mold temperature and molding cycle were changed as shown in Table 2. A molded body was produced in the same manner as in Example 6 except for the above. The same evaluation as in Reference Example 1 was performed on the obtained molded body. The results are shown in Table 2.

[0040]

[Table 2]

(Example 11) The raw material pellets used in Reference Example 1 were charged into a single-screw extruder manufactured by Mitsubishi Heavy Industries, Ltd. equipped with a T-die, and a barrel temperature of 200.
Extrusion was carried out at ℃, and then rapidly cooled by a cast roll to obtain a sheet. The obtained sheet was clamped in a thermoforming machine (“PLAVAC-FE36PH” manufactured by Sanwa Kogyo Co., Ltd.), preheated to a sheet temperature of 100 ° C. using an infrared heater, and then plugged into the mold. It was pushed into and preformed. Then, the inside of the mold was evacuated to form a tray. However, as the molding conditions, the mold was heated to 75 ° C., and the mold contact time was 30 seconds. The tray-shaped molded product thus obtained was evaluated in the same manner as in Reference Example 1, and the relative crystallinity was 60% and the impact resistance was 4.5 KJ /
It was mm ² and was evaluated as “◯” in terms of moldability, heat resistance and wet heat durability.

[0042]

As described above in detail, according to the present invention, excellent heat resistance, impact resistance and wet heat resistance can be achieved at the same time without substantially impairing the biodegradability inherent in lactic acid resins. It is possible to provide a resin composition of the lactic acid-based resin and a molded article that are provided.

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) C08L 67/00-67/02 C08L 67/04

Claims (5)

(57) [Claims] 1. The mass ratio of L-lactic acid and D-lactic acid is 10.
50 to 95% by mass of lactic acid-based resin having 0: 0 to 90:10, or 0: 100 to 10:90, and 5 to 5 of aliphatic polyester resin having a glass transition temperature (Tg) of 0 ° C. or less.
0% by mass of the composition, and based on 100 parts by mass of the composition, 0.1 to 10 parts by mass of a hydrolysis inhibitor as a main component , and the hydrolysis inhibitor is a layered silicate, Oh
Group consisting of reffin resin and carbodiimide compound
A molded body, which is at least one selected from the group consisting of: 2. The melting point of the aliphatic polyester is 65 to 5.
It is 99 degreeC, The molded object of Claim 1 characterized by the above-mentioned. 3. The relative crystallinity of the lactic acid resin is 50 to 50.
It is 100%, The molded object of Claim 1 or 2 characterized by the above-mentioned. 4. The mass ratio of L-lactic acid and D-lactic acid is 10.
50 to 95% by mass of lactic acid-based resin having 0: 0 to 90:10, or 0: 100 to 10:90, and 5 to 5 of aliphatic polyester resin having a glass transition temperature (Tg) of 0 ° C. or less.
0% by mass of the composition, and based on 100 parts by mass of the composition, 0.1 to 10 parts by mass of a hydrolysis inhibitor as a main component , and the hydrolysis inhibitor is a layered silicate, Oh
Group consisting of reffin resin and carbodiimide compound
A resin composition comprising at least one selected from the group consisting of: 5. The mass ratio of L-lactic acid and D-lactic acid is 10.
50 to 95% by mass of lactic acid-based resin having 0: 0 to 90:10, or 0: 100 to 10:90, and 5 to 5 of aliphatic polyester resin having a glass transition temperature (Tg) of 0 ° C. or less.
0% by mass of the composition, and based on 100 parts by mass of the composition, 0.1 to 10 parts by mass of a hydrolysis inhibitor as a main component , and the hydrolysis inhibitor is a layered silicate, Oh
Group consisting of reffin resin and carbodiimide compound
A method for producing a molded article, which is formed by using at least one resin composition selected from the group consisting of injection molding, blow molding, sheet thermoforming, and press molding.