JP2003335933A - Injection molded product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a biodegradable injection molded product having excellent impact, heat and hydrolytic resistances and scarcely deteriorating biodegradability essentially possessed by a lactic acid resin. <P>SOLUTION: The biodegradable injection molded product is composed of a resin composition containing the lactic acid resin and an aromatic aliphatic polyester. The mixing ratio of the lactic acid resin to the aromatic aliphatic polyester is within the range of (70:30) to (90:10) expressed in terms of mass ratio. In the resin composition, 5-30 mass% of an inorganic filler may be contained and a carbodiimide compound may further be contained. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a biodegradable injection-molded article, and more particularly to a biodegradable injection-molded article containing a lactic acid resin and an aromatic-aliphatic polyester.

[0002]

2. Description of the Related Art Due to increasing environmental problems in recent years, when plastic products are discarded, they decompose over time in the natural environment.
It is required that it disappears and ultimately does not adversely affect the natural environment. Conventional plastics are stable in the natural environment for a long period of time and have a low bulk specific gravity, so problems such as promoting the shortening of the life of waste landfills and impairing the natural landscape and living environment of wild animals and plants are pointed out. It had been. Therefore, biodegradable resin materials have attracted attention. It is known that the biodegradable resin gradually disintegrates and decomposes in soil or in water due to hydrolysis or biodegradation, and finally becomes a harmless decomposed product due to the action of microorganisms. Further, waste treatment can be easily performed by composting.

Biodegradable resins that have been put into practical use include aliphatic polyesters, modified PVA, cellulose ester compounds, starch modified products, and blends thereof. Each of these biodegradable resin materials has its own characteristic, and it can be considered to be used in accordance with this characteristic. Of these, aliphatic polyesters have begun to be widely used because of their wide range of properties and processability similar to general-purpose resins. In addition, among the aliphatic polyesters, lactic acid-based resins are excellent in transparency, rigidity, heat resistance, etc., and therefore, have attracted attention in the field of film packaging and injection molding as substitute materials for polystyrene and polyethylene terephthalate.

However, when compared with ABS used for home electric appliances, automobile parts, and other injection-molded products, the impact resistance of lactic acid-based resin is low and it is difficult to use it as a substitute material for ABS. Therefore, as disclosed in JP-A-10-87976, as a means for imparting impact resistance, polybutylene succinate, polybutylene succinate / adipate copolymer, etc. are blended as an aliphatic polyester other than a lactic acid resin. The approach is taken. In this method, the amount of the aliphatic polyester compounded must be increased in order to obtain the impact resistance improving effect, which results in softening of the molded product and deterioration of heat resistance, which is not practically sufficient. As for impact resistance, JISK-7110 is used in consideration of the performance of resins used for home electric appliances and car parts.
Impact strength (notched, 23 ° C) based on
Then, 15 kJ / m ² or more is preferable. Similarly, the heat resistance is preferably 55 ° C. or higher in terms of the deflection temperature under load (A method, edgewise) based on JISK-7191. In addition, lactic acid-based resin, compared to other aliphatic polyester,
It is about to be mass-produced industrially,
In addition, since it is advantageous in terms of price, it is possible to supply the product stably and at low cost if the lactic acid-based resin is contained in a large amount in the injection-molded article.

A molded product containing a large amount of an aliphatic polyester resin is hydrolyzed by water vapor in the air or moisture in the contents or moisture from the outside during long-term storage or long-term use, resulting in deterioration of mechanical properties. There was a big problem in practical use such as inviting. In particular, in an atmosphere of high temperature and high humidity of 60 ° C. and 60% RH or more, hydrolysis occurs in a short period of time, and the molded body may decompose in several hours to several weeks. From the viewpoint of hydrolysis resistance, it is practically preferable that the retention of molecular weight is 70% or more in a 100-hour wet heat test under an atmosphere of 85 ° C. and 80% RH.

[0006]

The object of the present invention is to provide a biodegradable injection-molded article which is excellent in heat resistance and impact resistance and has excellent hydrolysis resistance with almost no deterioration in biodegradability. Is to provide.

[0007]

DISCLOSURE OF THE INVENTION The inventors of the present invention have made intensive studies in view of the present situation as a result, and as a result, completed the invention of high effect. That is, the injection-molded article of the present invention is an injection-molded article composed of a resin composition containing a lactic acid-based resin and an aromatic aliphatic polyester, and the mixing ratio of the lactic acid-based resin and the aromatic-aliphatic polyester is a mass ratio. And is in the range of 70:30 to 90:10. Here, the resin composition may further contain 5 to 30 mass% of an inorganic filler. Also,
The resin composition may further contain a carbodiimide compound. The aromatic-aliphatic polyester may be a polybutylene adipate / terephthalate copolymer or a tetramethylene adipate / terephthalate copolymer. Further, the injection-molded article may be crystallized at a temperature within the range of 60 to 130 ° C. Further, the injection-molded product has an Izod impact strength of 15 kJ / m ² or more measured according to JIS K-7110, and a load deflection temperature of 55 ° C. or more measured in the edgewise direction according to JIS K-7191. Can be

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is described in detail below. The lactic acid-based resin used in the present invention includes poly (L-lactic acid) whose structural unit is L-lactic acid, poly (D-lactic acid) whose structural unit is D-lactic acid, L-lactic acid and D-lactic acid whose structural unit is L-lactic acid. Which is a poly (DL-lactic acid) or a mixture thereof, and further, a copolymerization weight with other hydroxycarboxylic acid units such as α-hydroxycarboxylic acid and (aliphatic) diol / (aliphatic) dicarboxylic acid. It may be a combination. However, at this time, the DL structure of the lactic acid-based resin is L body: D body = 100: 0.
~ 90: 10, or L body: D body = 0: 100 to 1
It is preferably 0:90, and L-form: D-form = 100:
0-94: 6, or L-body: D-body = 0: 100-
It is more preferably 6:94. Outside this range, the heat resistance of the component is difficult to obtain, and the application may be limited. Typical lactic acid resins include Shimadzu's Lacty series, Mitsui Chemicals Lacia series, and Cargill Dow's Nature Works series.

The lactic acid-based resin can be polymerized by condensation polymerization,
Any known method such as ring-opening polymerization method can be adopted. For example, in the condensation polymerization method, L-lactic acid or D-lactic acid,
Alternatively, a lactic acid resin having an arbitrary composition can be obtained by directly subjecting the mixture to dehydration polycondensation. In the ring-opening polymerization method, a polylactic acid-based polymer can be obtained by using lactide, which is a cyclic dimer of lactic acid, and a catalyst selected as necessary while using a polymerization regulator and the like. L-Lactide, which is a dimer of L-lactic acid, and 2 of D-lactic acid, are included in lactide.
There is D-lactide which is a monomer, and DL-lactide which is composed of L-lactic acid and D-lactic acid, and a lactic acid-based resin having an arbitrary composition and crystallinity is obtained by mixing and polymerizing these as needed. be able to.

Further, if necessary, for example, to improve the heat resistance, a small amount of a non-aliphatic dicarboxylic acid such as terephthalic acid and / or a non-aliphatic diol such as an ethylene oxide adduct of bisphenol A is used as a copolymerization component. You may use. 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 other hydroxy-carboxylic acid units copolymerized with the lactic acid-based resin are 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-hydroxyn-butyric acid, 2-hydroxy-3,3-dimethylbutyric acid, 2-hydroxy-3-methylbutyric acid, 2-methyllactic acid, 2 Examples thereof include bifunctional aliphatic hydroxycarboxylic acids such as hydroxycaproic acid and lactones such as caprolactone, butyrolactone and valerolactone.

Examples of the 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.

The weight average molecular weight of the lactic acid resin is 50,000 to 4
It is preferably in the range of 0,000, and more preferably 100,000 to 250,000. When the weight average molecular weight of the lactic acid resin is less than 50,000, practical physical properties are hardly exhibited and 4
If it is more than 0,000, the melt viscosity will be too high and the moldability will be poor.

The aromatic aliphatic polyester preferably used in the present invention is a biodegradable aromatic aliphatic polyester composed of an aromatic dicarboxylic acid component, an aliphatic dicarboxylic acid component, and an aliphatic diol component. Examples of the aromatic dicarboxylic acid component include isophthalic acid, terephthalic acid, and 2,6-naphthalenedicarboxylic acid, and examples of the aliphatic dicarboxylic acid component include succinic acid, adipic acid, suberic acid, sebacic acid, and the like.
Dodecanedioic acid and the like can be mentioned, and examples of the aliphatic diol component include ethylene glycol, 1,4-butanediol, 1,4-cyclohexanedimethanol and the like. Two or more kinds of aromatic dicarboxylic acid components, aliphatic dicarboxylic acid components or aliphatic diol components can be used. In the present invention, the most preferably used aromatic dicarboxylic acid component is terephthalic acid, the aliphatic dicarboxylic acid component is adipic acid,
The aliphatic diol component is 1,4-butanediol.

It is known that an aliphatic polyester composed of an aliphatic dicarboxylic acid and an aliphatic diol has biodegradability, but in order to exhibit biodegradability in an aromatic aliphatic polyester, it is necessary to provide a space between aromatic rings. The presence of aliphatic chains is required. Therefore, the aromatic dicarboxylic acid component of the aromatic aliphatic polyester used in the present invention is preferably 50 mol% or less. A typical example of the aromatic-aliphatic polyester is a copolymer of polybutylene adipate and terephthalate (BAS
"Ecoflex" manufactured by Company F) or a copolymer of tetramethylene adipate and terephthalate (Eastman C
"EastarBio" manufactured by chemicals, and the like.

The mass ratio of the lactic acid resin to the aromatic-aliphatic polyester is preferably in the range of 70:30 to 90:10, and more preferably in the range of 75:25 to 85:15. preferable. If the amount of the aromatic-aliphatic polyester compounded exceeds 30% by mass with respect to the total amount of the resin composition, the molded product tends to be softened and the heat resistance tends to decrease.
If it is less than 10% by mass, the effect of improving impact resistance cannot be obtained. Conventionally, as a means for improving the impact resistance of a lactic acid resin, a method of blending an aliphatic polyester other than the lactic acid resin is generally known. As the aliphatic polyester other than the lactic acid-based resin, an aliphatic polyester mainly containing an aliphatic dicarboxylic acid or its derivative and an aliphatic polyhydric alcohol is widely used. Representative examples include the Showa Polymer Co., Ltd. Bionore series.

In order to exert the impact resistance improving effect by blending the aliphatic polyester other than the lactic acid type resin, the proportion of the aliphatic polyester other than the lactic acid type resin is set to 30% by mass or more in the total amount of the resin composition. There is a need. However, when the proportion of the aliphatic polyester other than the lactic acid-based resin in the injection molded product is 30% by mass or more, the molded product is softened and the heat resistance is lowered, which causes a problem in practical use.

However, if the aromatic-aliphatic polyester is used, the lactic acid-based resin and the aromatic-aliphatic polyester are in a mass ratio of 70:30 to 90:10, and more preferably 75 :.
By mixing in the range of 25 to 85:15, the effect of improving impact resistance equal to or more than that in the case of blending 30% by mass or more of the aliphatic polyester can be obtained, so that both impact resistance and heat resistance can be achieved. It will be easier.

In order to further improve the heat resistance of the molded body obtained by injection molding, it is effective to heat the molded body to crystallize it. The heat treatment temperature is
The range of 60 to 130 ° C is preferable, and the range of 70 to 90 ° C is more preferable. If the heat treatment temperature is lower than 60 ° C., crystallization does not proceed, and if it is higher than 130 ° C., deformation or shrinkage is likely to occur when the molded body is cooled. The heating time is appropriately determined depending on the composition and the heat treatment temperature. For example, when the heating temperature is 70 ° C., it is preferable to perform the heat treatment for 15 minutes to 5 hours. If the heating temperature is 130 ° C, 10
It is preferable to perform heat treatment for seconds to 30 minutes. As a method of crystallizing, the method of raising the temperature of the mold after injection molding to crystallize in the mold, or after taking out the injection molded body from the mold in an amorphous state, hot air, steam, hot water, far infrared rays Examples thereof include a method of crystallizing with a heater or an IH heater. At this time, the injection molded body does not have to be fixed, but it is preferable to fix it with a mold, a resin mold or the like in order to prevent deformation of the molded body. Also, considering productivity,
It is preferable to perform the heat treatment in the packaged state.

In the present invention, by further adding an inorganic filler to the resin composition, the effect of preventing deformation at the time of releasing from the mold and the effect of preventing shrinkage and warpage during heating can be obtained. The addition amount of the inorganic filler is preferably in the range of 5 to 30 mass% in the total amount of the resin composition. If the amount of the inorganic filler added is less than 5% by mass, deformation may occur when the mold is released from the mold, or shrinkage during heating may increase. If the amount added exceeds 30% by mass,
This causes a decrease in strength of the molded product, which causes a practical problem.

Specific examples of the inorganic filler used in the present invention include talc, kaolin, calcium carbonate, bentonite, mica, sericite, glass flakes, graphite, magnesium hydroxide, aluminum hydroxide, antimony trioxide, barium sulfate and boro. Examples thereof include zinc acid salt, hydrous calcium borate, alumina, magnesia, wollastonite, xonotlite, sepiolite, whiskers, glass fibers, metal powder, beads, silica balloons, silas balloons, and organic balloons. Further, by treating the surface of the inorganic filler with titanic acid, a fatty acid, a silane coupling agent or the like, it is possible to improve the adhesiveness with the resin and improve the effect of the inorganic filler.

In order to impart hydrolysis resistance to the injection-molded article of the present invention, it is effective to add the carbodiimide compound within the range of 0.5 to 10 parts by mass with respect to 100 parts by mass of the resin composition. is there. If it is less than this range, the effect of improving hydrolysis resistance is not exhibited, and if it is more than this range, the appearance of the molded product due to bleeding out of the carbodiimide compound is deteriorated and mechanical properties are deteriorated due to plasticization. In addition, biodegradability and compost degradability may be impaired.

The carbodiimide compound preferably used in the present invention includes those having a basic structure represented by the following general formula. -(N = C = NR-) _n -In the formula, n represents an integer of 1 or more, and R represents an organic bond unit. Usually, n is appropriately set between 1 and 50. Examples of R include aliphatic, alicyclic and aromatic bond units.

Specifically, for example, poly (4,4'-diphenylmethanecarbodiimide), poly (p-phenylenecarbodiimide), poly (m-phenylenecarbodiimide), poly (tolylcarbodiimide), poly (diisopropylphenylenecarbodiimide), Poly (methyl-
Diisopropyl phenylene carbodiimide), poly (triisopropyl phenylene carbodiimide), etc., and these monomers are mentioned. In the present invention, the carbodiimide compounds may be used alone or in combination of two or more kinds.

In the resin composition, heat stabilizers, antioxidants, UV absorbers, light stabilizers, pigments, colorants, lubricants, nucleating agents, plasticizers, etc. may be added to the resin composition as long as the effects of the present invention are not impaired. Additives can be formulated.

Next, a method for molding an injection molded body according to the present invention will be described. The lactic acid-based resin and the aromatic-aliphatic polyester, and if necessary, the inorganic filler, the carbodiimide compound, and other additives can be mixed by putting the respective raw materials into the same injection molding machine. Injecting the raw materials into the injection molding machine, mixing them, and then injection molding from the injection molding machine as it is, or extruding the dry-blended raw materials into a strand shape using a twin-screw extruder to create pellets, then injecting again There is a method of forming an injection molded body using a molding machine.

In any of the methods, it is necessary to consider the decrease in the molecular weight due to the decomposition of the raw materials, but it is preferable to select the latter for uniform mixing. In the present invention, for example, a lactic acid-based resin and an aromatic-aliphatic polyester are sufficiently dried to remove water, then melt-mixed using a twin-screw extruder and extruded into a strand shape to form pellets. However, the lactic acid-based resin has an L-lactic acid structure and a D-lactic acid structure.
It is preferable to appropriately select the melt extrusion temperature in consideration of the fact that the melting point changes depending on the composition ratio of the lactic acid structure and the melting point of the resin composition changes depending on the mixing ratio of the aromatic-aliphatic polyester. In practice, a temperature range of 100-250 ° C is usually selected.

The pellets produced by the above method are sufficiently dried to remove water, and then injection molded. The injection molding method of the present invention is not particularly limited, but typical injection molding methods such as general injection molding method for thermoplastic resin, gas assist molding method and injection compression molding method can be adopted. . According to other purposes, in-mold molding method, gas press molding method, two-color molding method, sandwich molding method, PUSH-PULL, SCORIM other than the above methods
Etc. can also be adopted.

The injection molding apparatus includes a general injection molding machine, a gas assist molding machine, an injection compression molding machine and the like, and molding dies and auxiliary equipment used for these, a mold temperature control device, a raw material drying device and the like. Composed. The molding conditions are preferably such that the temperature of the molten resin is 170 ° C. to 210 ° C. in order to avoid thermal decomposition of the resin in the injection cylinder.

When the injection-molded body is obtained in an amorphous state, the mold temperature is set as low as possible in order to shorten the cooling time of the molding cycle (mold closing-injection-holding pressure-cooling-mold opening-unloading). Preferably. Mold temperature is generally 15
C. to 55.degree. C., and it is also preferable to use a chiller. However, it is advantageous to raise the temperature within this range in order to suppress shrinkage, warpage, and deformation of the molded body during post-crystallization.

In the case of the "inorganic filler filling system" in which an inorganic filler is added to the resin composition, flow marks are more likely to occur on the surface of the molded product as the amount of the inorganic filler filled increases. The injection speed of the inorganic filler-filled system needs to be lower than the injection speed of the "unfilled system" in which the resin composition is not filled with the inorganic filler. For example, when a resin composition containing 15% by mass of talc is injection-molded with an injection molding machine having a screw diameter of 25 mm equipped with a plate mold having a thickness of 2 mm, if the injection speed is 30 mm / sec or less, molding without flow marks I got a body. 50 mm for unfilled system
The flow mark did not occur even at / sec.

When sink marks are likely to occur, it is preferable that the holding pressure and the holding time are sufficient. For example, the holding pressure is preferably set in the range of 30 MPa to 100 MPa, and the holding time is appropriately set in the range of 1 second to 15 seconds depending on the shape and wall thickness of the molded body. When molding the plate having a wall thickness of 2 mm, the holding time is about 3 seconds.

After the molten resin is filled in the heated mold,
It can be crystallized in the mold by holding it in the mold for a certain period of time. The mold temperature is 60 ° C to 13
It is preferably 0 ° C, more preferably 70 ° C to
90 ° C. If the mold temperature is lower than 60 ° C, it takes a long time to crystallize and the cycle becomes too long. Meanwhile, 130
If it exceeds ℃, deformation may occur at the time of release.

The injection-molded article of the present invention has excellent heat resistance, impact resistance, and hydrolysis resistance, so that it can be used for household appliances.
It can be used as automobile parts and other general molded products in the same manner as conventional resins. For example, the present invention can form a calculator-type molded body. FIG. 1A is a plan view of a calculator-type molded body which is one of the embodiments of the present invention, and FIG. 1B is a front view thereof. 1 to 6 are perforated portions of the through holes, 1 is a portion to be a window portion for displaying calculation results and the like, 2 and 3 are portions to be a key portion for numbers and the like, 4, 5, 6
Is the part where the nail is applied.

[0035]

EXAMPLES The present invention will now be specifically described with reference to examples, but the present invention is not limited thereto. The measured values shown in the examples were measured and calculated under the following conditions.

(1) Impact resistance A No. 1 A test piece was prepared based on JISK-7110, and the Izod impact strength in the edgewise direction at 23 ° C. was measured. The Izod impact strength was set to 15 kJ / m ² as a practical standard.

(2) Heat resistance Based on JISK-7191, test pieces were prepared and the deflection temperature under load was measured. The measurement was performed under the conditions of edgewise direction and bending stress of 1.80 MPa applied to the test piece. The deflection temperature under load was set to 55 ° C. or higher as a practical standard.

(3) Dimensional stability Using an injection molding machine "IS50E" manufactured by Toshiba Machine Co., Ltd., a calculator type amorphous molded body shown in FIG. 1 was obtained. The molding conditions at this time are: cylinder temperature 195 ° C., mold temperature 25 ° C., injection pressure 110 MPa, injection time 1.5 sec, holding pressure 80.
MPa, holding time 3.0 seconds, back pressure 10 MPa, screw rotation number 110 rpm. After molding, the molded body was conditioned in a measurement room (temperature 23 ° C., humidity 50% RH), and then the X and Y dimensions in FIG. 1 were measured. After that, the annealing treatment was performed under the designated heating condition (temperature and time). However, a constant temperature and constant humidity oven was used for the annealing treatment, and the compact was allowed to stand still without any load. Immediately after the annealing treatment, the molded body was taken out and the condition was adjusted in the measuring chamber. After conditioning for 24 hours,
The X and Y dimensions were measured again, and the shrinkage rate due to the annealing treatment was calculated. A three-dimensional measuring machine was used for the measurement. If the contraction rates of X and Y are both less than 1.0%, the symbol "○", X
Or, if any of the shrinkage ratios of Y is 1.0 or more and less than 2.0, the symbol “Δ” indicates that the shrinkage ratios of X and Y are both 2.0.
Those having a value of% or more are indicated by the symbol "x".

(4) Weight average molecular weight of aliphatic polyester-based biodegradable resin Chloroform as solvent and concentration of solution 0.2 wt / vol using gel permeation chromatography.
%, Solution injection volume 200 μL, solvent flow rate 1.0 mL / min,
The measurement was performed at a solvent temperature of 40 ° C., and the weight average molecular weight of the lactic acid resin was calculated in terms of polystyrene. However, the weight average molecular weight of the standard polystyrene used was 200,000.
0, 430000, 110000, 35000, 100
00, 4000, 600.

(5) Hydrolysis resistance A wet heat test was carried out under the conditions of 85 ° C. and 80% RH to obtain 100
The molecular weight retention rate after the lapse of time was calculated by the following formula.
The molecular weight retention rate was set to 70% or more as a practical standard. Molecular weight retention rate (%) = {(weight average molecular weight after wet heat test) / (weight average molecular weight before wet heat test)} × 100

Example 1 Cargill as a lactic acid resin
"Nature Works 4031D" made by Dow
(L-lactic acid / D-lactic acid = 98.5 / 1.5, weight average molecular weight 200,000), BAS as aromatic aliphatic polyester
"Ecoflex" manufactured by Company F (24 mol% terephthalic acid, 26 mol% adipic acid, 5,4-butanediol 5)
0 mol%) and used in "Nature Works 403
1D, Ecoflex "was dry-blended in a mass ratio of 85:15 to obtain a resin composition. 180 mm using a 40 mmφ small-sized same-direction twin-screw extruder manufactured by Mitsubishi Heavy Industries
Compounded at 0 ° C into pellet form. The obtained pellets are L100 mm x W100 using an injection molding machine "IS50E" (screw diameter 25 mm) manufactured by Toshiba Machine Co., Ltd.
Two types of plate materials having different thicknesses of mm × t3 mm or t4 mm (hereinafter referred to as “3 mm plate” and “4 mm plate”) were injection molded. The main molding conditions are as follows. 1) Temperature condition: Cylinder temperature (195 ° C), mold temperature (20 ° C) 2) Injection condition: Injection pressure (115 MPa), holding pressure (55 MPa) 3) Measuring condition: Screw rotation speed (65 rpm), back pressure ( Next, the injection-molded body was allowed to stand in a baking tester (“DKS-5S” manufactured by Daiei Kagaku Seiki Seisakusho Co., Ltd.) and heat-treated at 70 ° C. for 3.5 hours. The Izod impact strength was evaluated using a 4 mm plate, and the deflection temperature under load was evaluated using a 3 mm plate. The results are shown in Table 1.

(Example 2) In Example 1, "Nat
ure Works 4031D "and" Ecofle
An injection-molded article was produced in the same manner as in Example 1 except that the dry blend ratio of “x” was changed to 80:20 by mass ratio. Moreover, the same evaluation as in Example 1 was performed. The results are shown in Table 1.
Shown in.

(Third Embodiment) In the first embodiment, "Nat
ure Works 4031D "and" Ecofle
An injection-molded body was prepared in the same manner as in Example 1 except that the dry blend ratio of “x” was changed to 75:25 by mass ratio. Moreover, the same evaluation as in Example 1 was performed. The results are shown in Table 1.
Shown in.

Example 4 In Example 1, as the aromatic-aliphatic polyester, Eastman Chemi was used.
"Nature Work" manufactured by Cals (EastarBio) (22 mol% terephthalic acid, 28 mol% adipic acid, 50 mol% 1,4-butanediol) was used.
An injection-molded article was prepared in the same manner as in Example 1 except that the resin composition was dry-blended with "s 4031D" and "Eastar Bio" at a mass ratio of 80:20. Moreover, it evaluated similarly to Example 1. The results are shown in Table 1.

[0045]

[Table 1]

(Example 5) "Microace L1" manufactured by Nippon Talc Co., Ltd. was used as an inorganic filler, and "Nat" was used.
ure Works 4031D "and" Ecofle
x "and" Microace L1 "in a mass ratio of 80: 1
An injection-molded article was prepared in the same manner as in Example 1 except that the resin composition was dry-blended at a ratio of 5: 5. In addition to impact resistance and heat resistance, dimensional stability was evaluated. The results are shown in Table 2.

(Embodiment 6) In the fifth embodiment, "Nat
ure Works 4031D "and" Ecofle
x "and" Microace L1 "in a mass ratio of 70: 1
An injection-molded article was prepared in the same manner as in Example 1 except that the resin composition was dry-blended at a ratio of 5:15. Moreover, the same evaluation as in Example 5 was performed. The results are shown in Table 2.
Shown in.

(Embodiment 7) In Embodiment 5, "Nat
ure Works 4031D "and" Ecofle
x "and" Microace L1 "in a mass ratio of 50: 2
An injection molded article was prepared in the same manner as in Example 1 except that the resin composition was dry blended at a ratio of 0:30. Moreover, the same evaluation as in Example 5 was performed. The results are shown in Table 2.
Shown in.

[0049]

[Table 2]

Comparative Example 1 Instead of the resin composition in Example 1, "Nature Works 4031D" was used.
An injection molded body was prepared in the same manner as in Example 1 except that was used. Moreover, the same evaluation as in Example 1 was performed. The results are shown in Table 3.

(Comparative Example 2) In Example 1, as the aliphatic polyester, "Bionole 300" manufactured by Showa High Polymer Co., Ltd.
3 "using" Nature Works 4031D "
An injection-molded article was prepared in the same manner as in Example 1, except that the resin composition was dry-blended in a mass ratio of 80:20 with “Bionole 3003”. Also,
The same evaluation as in Example 1 was performed. The results are shown in Table 3.

(Comparative Example 3) In Example 1, "Nat
ure Works 4031D "and" Bionore 30
An injection-molded article was prepared in the same manner as in Example 1 except that the resin composition was dry-blended in a mass ratio of 60:40. Moreover, the same evaluation as in Example 1 was performed. The results are shown in Table 3.

(Comparative Example 4) In Example 1, "Nat
ure Works 4031D "and" Ecofle
An injection-molded article was prepared in the same manner as in Example 1, except that the resin composition was dry-blended at a mass ratio of 95: 5. Moreover, the same evaluation as in Example 1 was performed. The results are shown in Table 3.

(Comparative Example 5) In Example 1, "Nat
ure Works 4031D "and" Ecofle
x ”was changed to a resin composition which was dry blended at a mass ratio of 60:40, in the same manner as in Example 1,
An injection molded body was created. Moreover, the same evaluation as in Example 1 was performed. The results are shown in Table 3.

[0055]

[Table 3]

(Examples 8 and 9) In Example 1, "Stabaxol P" manufactured by Rhein Chemie was used as the carbodiimide compound, and "Nature Works 40" was used.
31D "," Ecoflex ", and" Microace L
1 ”and“ Stavaxol P ”as shown in Table 4,
Example 8 was changed to a resin composition which was dry-blended at a mass ratio of 70: 15: 15: 1.5, and Example 9 was changed to a mass ratio of 70: 15: 15: 3.0, except that the resin composition was dry blended. An injection molded body was prepared in the same manner as in Example 1. In addition, impact resistance, heat resistance, and hydrolysis resistance were evaluated. The results are shown in Table 4.

[0057]

[Table 4]

As is clear from Tables 1 to 4, Examples 1 to 1
The injection molded product of No. 9 has an Izod impact strength of 15 kJ / m.
²As described above, the deflection temperature under load is 55 ° C or higher, and the impact resistance is high.
It was found that both the heat resistance and the heat resistance were excellent. Also, the table
As is clear from 2, the inorganic filler was further added.
The injection-molded articles of Examples 5 to 7 have excellent dimensional stability.
I found out. As is clear from Table 4, carbodii
Injection-molded articles of Examples 8 to 9 further containing a amide compound
Was found to have a high retention of molecular weight. In addition,
The injection-molded articles of Examples 1 to 9 are biodegradable, so
It is also excellent in terms of environmental protection. On the other hand, a comparative example
The injection molded bodies 1, 2, and 4 have an Izod impact strength of 15
kJ / m ²Less than, and inferior in impact strength
there were. In addition, the injection-molded articles of Comparative Examples 2, 3 and 5 were
Deflection temperature is less than 55 ° C, which is inferior in heat resistance.
there were. Thus, in Comparative Examples 1 to 5, impact resistance and
One or more of heat resistance is impractical
It was

[0059]

According to the present invention, the biodegradability having excellent impact resistance, heat resistance, and further hydrolysis resistance is hardly impaired while the biodegradability originally possessed by the lactic acid resin is not impaired. An injection-molded article can be provided.

[Brief description of drawings]

FIG. 1A is a plan view of an injection-molded article according to a first embodiment of the present invention, and FIG. 1B is a front view.

[Explanation of symbols]

1-6 Perforated part

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) // C08L 101/16 C08L 101/16 (C08L 67/04 67/04 67:02) 67:02 B29K 67 : 00 B29K 67:00 105: 16 105: 16 509: 00 509: 00 (72) Inventor Jun Takagi 5-8 Mitsuyacho, Nagahama City, Shiga Prefecture Mitsubishi Plastics, Inc. Nagahama Factory F-term (reference) 4F071 AA43 AB01 AC12 AE17 AF14Y AF45Y AG27 AH07 AH12 BB05 BC17 4F206 AA24 AB16 JA07 JF01 JF02 JL02 4J002 CF03X CF18W CF19W DA026 DE076 DE146 DG046 DJ036 DJ046 DJ056 DL006 ER007 FA016 FD016 GC00 GN00 GQ00 4J200 AA06 AA16 BA10 BA14 DA28 EA05 EA07

Claims (6)

[Claims] 1. An injection-molded article comprising a resin composition containing a lactic acid-based resin and an aromatic aliphatic polyester, wherein a mixing ratio of the lactic acid-based resin and the aromatic aliphatic polyester is 70: An injection-molded article characterized by being in the range of 30 to 90:10. 2. The injection molded article according to claim 1, wherein the resin composition further contains 5 to 30% by mass of an inorganic filler. 3. The injection-molded article according to claim 1, wherein the resin composition further contains a carbodiimide compound. 4. The aromatic aliphatic polyester is a polybutylene adipate / terephthalate copolymer or a tetramethylene adipate / terephthalate copolymer, and the aromatic aliphatic polyester is any one of claims 1 to 3. Injection molded body. 5. The injection-molded product according to any one of claims 1 to 4, wherein the injection-molded product is crystallized at a temperature within a range of 60 to 130 ° C. 6. The Izod impact strength measured according to JIS K-7110 is 15 kJ / m ² or more, and the deflection temperature under load measured in the edgewise direction according to JIS K-7191 is 55 ° C. or more. The injection-molded article according to any one of claims 1 to 5, which is characterized by the above-mentioned.