JP2008069245A - Polylactic acid-based resin composition, and molded form obtained by molding the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a biodegradable polyester resin composition improved in heat resistance, and to provide a molded form improved in productivity by shortening the molding cycle of the resin composition. <P>SOLUTION: The resin composition comprises 100 pts.mass of a polylactic acid-based resin(A), 0.1-5 pts.mass of one or more compounds(B) represented by general formulas(1) to (3) mentioned below and 0.5-20 pts.mass of one or more compounds(C) selected from aliphatic ester derivatives and aliphatic polyether derivatives. General formulas(1) to (3) are as follows, respectively: R<SP>1</SP>-(CONH-R<SP>2</SP>)<SB>a</SB>, R<SP>9</SP>-(NHCO-R<SP>10</SP>)<SB>f</SB>, and R<SP>11</SP>-(CONHNHCO-R<SP>12</SP>)<SB>h</SB>. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a polylactic acid resin composition and a molded body obtained by molding the same, and in particular, a polylactic acid resin composition containing a polylactic acid resin, an organic crystal nucleating agent, and a plasticizer, And it is related with the molded object formed by shape | molding it.

  In recent years, polylactic acid-based resins having biodegradability have attracted attention from the viewpoint of environmental conservation. Polylactic acid is a crystalline polymer, has a higher melting point and higher heat resistance than other biodegradable polyester resins. Polylactic acid can be mass-produced, so the cost is low and its usefulness is high. Furthermore, polylactic acid can be produced using plants such as corn and sweet potato as raw materials, and can contribute to saving of depleted resources such as oil.

  However, polylactic acid generally has a slower crystallization rate than PET, which is generally considered to have a slow crystallization rate, and therefore has a long molding cycle and is inferior in mechanical strength and heat resistance of the resulting molded product. There is also a drawback.

  In order to overcome such drawbacks, for example, as a method for improving the crystallization speed of a biodegradable polyester resin, a method of adding ordinary talc, silica, calcium lactate, etc. as a crystal nucleating agent to a lactic acid polymer is proposed. (For example, Patent Document 1). However, in the method described in Patent Document 1, there is a problem that crystallization is insufficient because the resin is not heat-treated, and a molding cycle is long due to a slow crystallization rate of the polymer, and therefore, productivity is poor. is there.

In addition, a low molecular weight compound having an amide group and a layered clay mineral organized with an organic onium salt are added to polylactic acid, and a synergistic effect is proposed to improve the crystallization speed and heat resistance of polylactic acid. (For example, Patent Document 2). However, although the crystallization speed and the heat resistance are improved in the one described in Patent Document 2, the effect is still insufficient, the molding cycle at the time of injection molding is long, and the mechanical strength that can withstand actual use Has not yet been granted.
JP-A-8-193165 JP 2003-226801 A

  The present invention is intended to solve the above-described problems, and improves the heat resistance of the biodegradable polyester resin composition and improves the productivity by shortening the molding cycle.

  As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by using a specific organic crystal nucleating agent and a plasticizer in combination in a polylactic acid-based resin. It was found and reached the present invention.

That is, the gist of the present invention is as follows.
(1) 0.1 to 5 parts by mass of one or more compounds (B) represented by the following general formulas (1) to (3) with respect to 100 parts by mass of the polylactic acid resin (A), and aliphatic A resin composition comprising 0.5 to 20 parts by mass of one or more compounds (C) selected from ester derivatives or aliphatic polyether derivatives.

R ^1- (CONH-R ² ) a (1)
[Wherein, R ¹ represents a saturated or unsaturated aliphatic residue, saturated or unsaturated alicyclic acid residue or aromatic residue having 2 to 30 carbon atoms. R ² is an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 2 to 18 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, a cycloalkenyl group having 3 to 12 carbon atoms, a phenyl group, a naphthyl group, or an anthryl group. Represents a group represented by formula (a), formula (b), formula (c) or formula (d). a shows the integer of 2-6. ]

Ｒ⁹−（ＮＨＣＯ−Ｒ¹⁰） f （２）
［式中、Ｒ⁹は、炭素数２〜３０の飽和あるいは不飽和の脂肪族残基、不飽和の脂環族残基または芳香族残基を表す。Ｒ¹⁰は前記のＲ²と同義である。ｆは２〜６の整数を示す。］
Ｒ¹¹−（ＣＯＮＨＮＨＣＯ−Ｒ¹²） ｈ （３）
［式中、Ｒ¹¹は、炭素数２〜３０の飽和あるいは不飽和の脂肪族残基、不飽和の脂環族残基または芳香族残基を表す。Ｒ¹²は前記のＲ²と同義である。ｈは２〜６の整数を示す。］

^{R 9 - (NHCO-R 10} ) f (2)
[Wherein R ⁹ represents a saturated or unsaturated aliphatic residue, unsaturated alicyclic residue or aromatic residue having 2 to 30 carbon atoms. R ¹⁰ has the same meaning as R ² described above. f shows the integer of 2-6. ]
^{R 11 - (CONHNHCO-R 12} ) h (3)
[Wherein R ¹¹ represents a saturated or unsaturated aliphatic residue, unsaturated alicyclic residue or aromatic residue having 2 to 30 carbon atoms. R ¹² has the same meaning as R ² described above. h represents an integer of 2 to 6. ]

  (2) The polylactic acid resin (A) is 0.01 to 20 parts by mass of the (meth) acrylic acid ester compound (D) and 0.1% of the peroxide (E) with respect to 100 parts by mass of the polylactic acid resin. The resin composition according to (1), which is a crosslinked polylactic acid resin obtained from a raw material containing 1 to 20 parts by mass.

  (3) The polylactic acid resin (A) is (i) polylactic acid, or (ii) a mixture of polylactic acid and a biodegradable polyester obtained by copolymerizing a lactic acid component. The resin composition of (1) or (2).

  (4) Compound (B) is N, N′-ethylenebis (12-hydroxystearic) amide and / or N, N ′, N ″ -tricyclohexyltrimesic acid amide and / or octane The resin composition according to any one of (1) to (3), which is dicarboxylic acid dibenzoylhydrazide.

  (5) The resin composition according to any one of (1) to (4), wherein the compound (C) is glycerin diacetomonocaprate and / or glycerin diacetomonolaurate.

  (6) A molded product obtained by molding any of the resin compositions (1) to (5).

  According to the present invention, in a polylactic acid-based resin, by using a specific organic crystal nucleating agent and a plasticizer in combination, it has excellent heat resistance, moldability, mechanical strength, and also depends on petroleum-based products. A resin composition having a low degree can be provided. This resin composition has extremely high industrial utility value, such as being able to be formed into various molded bodies by various molding methods. In addition, since a biodegradable resin derived from a natural product called polylactic acid is used, it can contribute to saving depleted resources such as petroleum.

Hereinafter, the present invention will be described in detail.
The polylactic acid resin (A) used in the present invention contains polylactic acid as a main component. As polylactic acid, it is desirable to use poly (L-lactic acid), poly (D-lactic acid), and a mixture or copolymer thereof. From the viewpoint of biodegradability, it is preferable that poly (L-lactic acid) is the main component.

  In the present invention, as other accessory components, one or two or more resins selected from polyglycolic acid, polycaprolactone, polybutylene succinate, polyethylene succinate, polybutylene adipate terephthalate, polybutylene succinate terephthalate, etc. Can be used as the polylactic acid resin (A).

  It is preferable to use a mixture of polylactic acid and a biodegradable polyester obtained by copolymerizing a lactic acid component as the polylactic acid resin (A) because impact resistance is improved. The range of (polylactic acid) / (biodegradable polyester copolymerized with lactic acid component) = 95/5 to 70/30 (mass ratio) is preferable.

  The melting point of polylactic acid mainly composed of poly (L-lactic acid) varies depending on the optical purity. In the present invention, however, the melting point may be 160 ° C. or higher in consideration of the mechanical properties and heat resistance of the molded product. preferable. In order to obtain a melting point of 160 ° C. or higher in polylactic acid mainly composed of poly (L-lactic acid), the ratio of the D-lactic acid component may be less than about 3 mol%.

  The melt flow rate of the polylactic acid resin (A) at 190 ° C. and a load of 21.2 N is preferably 0.1 to 50 g / 10 minutes, more preferably 0.2 to 20 g / 10 minutes, and optimally 0.5. -10 g / 10 min. When the melt flow rate exceeds 50 g / 10 min, the melt viscosity is too low, and the mechanical properties and heat resistance of the molded product may be inferior. On the other hand, when the melt flow rate is less than 0.1 g / 10 minutes, the load during the molding process becomes too high, and the operability may be lowered.

  The polylactic acid resin (A) is usually produced by a known melt polymerization method or in combination with a solid phase polymerization method. As a method for adjusting the melt flow rate to a predetermined range, when the melt flow rate is too large, a small amount of chain extender such as a diisocyanate compound, a bisoxazoline compound, an epoxy compound, an acid anhydride, etc. A method for increasing the molecular weight is mentioned. Conversely, when the melt flow rate is too small, a method of mixing with a polyester resin or a low molecular weight compound having a large melt flow rate can be used.

  In the polylactic acid resin (A), monomers other than the main constituent components may be copolymerized. Examples of such monomers include terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1,5- Naphthalene dicarboxylic acid, methyl terephthalic acid, 4,4'-biphenyl dicarboxylic acid, 2,2'-biphenyl dicarboxylic acid, 4,4'-biphenyl ether dicarboxylic acid, 4,4'-diphenylmethane dicarboxylic acid, 4,4'- Aromatic dicarboxylic acids such as diphenylsulfone dicarboxylic acid and 4,4′-diphenylisopropylidenedicarboxylic acid; adipic acid, sebacic acid, oxalic acid, malonic acid, succinic acid, azelaic acid, undecanedioic acid, dodecanedioic acid, aikosan diacid Saturated aliphatic dicarboxylic acids such as acids and hydrogenated dimer acids; Unsaturated aliphatic dicarboxylic acids such as acid, maleic acid, itaconic acid, mesaconic acid, citraconic acid and dimer acid and their anhydrides; 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2- And cycloaliphatic dicarboxylic acid, 2,5-norbornene dicarboxylic acid, and alicyclic dicarboxylic acids such as tetrahydrophthalic acid. Examples of the diol component include ethylene glycol, propylene glycol, 1,3-butanediol, diethylene glycol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,10 -Aliphatic diols such as decanediol; Alicyclic diols such as 1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,2-cyclohexanedimethanol; Bisphenols such as bisphenol A and bisphenol S or the like An ethylene oxide adduct; aromatic diols such as hydroquinone and resorcinol may be copolymerized. Further, hydroxycarboxylic acids such as p-hydroxybenzoic acid, p- (2-hydroxyethoxy) benzoic acid, 6-hydroxycaproic acid, 3-hydroxybutyric acid, 3-hydroxyvaleric acid, δ-valerolactone, γ -Lactone compounds such as butyrolactone and ε-caprolactone may be copolymerized. Further, an ester-forming organic phosphorus compound may be copolymerized to impart flame retardancy.

  The polylactic acid-based resin (A) may be other polyester resin, such as polyethylene terephthalate, polycarbonate, polyarylate, polycyclohexylenedimethylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate copolymer, if the amount is small. Terephthalate, polybutylene isophthalate coterephthalate, polypolyethylene terephthalate / cyclohexylene dimethylene terephthalate, cyclohexylene dimethylene isophthalate coterephthalate, copolyester composed of p-hydroxybenzoic acid residue and ethylene terephthalate residue, plant-derived raw material Polytrimethylene terephthalate composed of a certain 1,3-propanediol or the like may be mixed.

  The compound (B) functions as a crystal nucleating agent added to the polylactic acid-based resin (A), and promotes crystallization of the polylactic acid-based resin (A) and improves the molding cycle. And it is comprised by 1 or more types of compounds represented by following General formula (1)-(3).

R ^1- (CONH-R ² ) a (1)
[Wherein, R ¹ represents a saturated or unsaturated aliphatic residue, saturated or unsaturated alicyclic acid residue or aromatic residue having 2 to 30 carbon atoms. R ² is an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 2 to 18 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, a cycloalkenyl group having 3 to 12 carbon atoms, a phenyl group, a naphthyl group, or an anthryl group. Represents a group represented by formula (a), formula (b), formula (c) or formula (d). a shows the integer of 2-6. ]

Ｒ⁹−（ＮＨＣＯ−Ｒ¹⁰） f （２）
［式中、Ｒ⁹は、炭素数２〜３０の飽和あるいは不飽和の脂肪族残基、不飽和の脂環族残基または芳香族残基を表す。Ｒ¹⁰は前記のＲ²と同義である。ｆは２〜６の整数を示す。］
Ｒ¹¹−（ＣＯＮＨＮＨＣＯ−Ｒ¹²） ｈ （３）
［式中、Ｒ¹¹は、炭素数２〜３０の飽和あるいは不飽和の脂肪族残基、不飽和の脂環族残基または芳香族残基を表す。Ｒ¹²は前記のＲ²と同義である。ｈは２〜６の整数を示す。］

^{R 9 - (NHCO-R 10} ) f (2)
[Wherein R ⁹ represents a saturated or unsaturated aliphatic residue, unsaturated alicyclic residue or aromatic residue having 2 to 30 carbon atoms. R ¹⁰ has the same meaning as R ² described above. f shows the integer of 2-6. ]
^{R 11 - (CONHNHCO-R 12} ) h (3)
[Wherein R ¹¹ represents a saturated or unsaturated aliphatic residue, unsaturated alicyclic residue or aromatic residue having 2 to 30 carbon atoms. R ¹² has the same meaning as R ² described above. h represents an integer of 2 to 6. ]

  Specific examples of the compound (B) include hexamethylene bis-9, 10-dihydroxystearic acid bisamide, p-xylylene bis-9, 10 dihydroxystearic acid amide, decane in terms of the effect as a crystal nucleating agent of polylactic acid resin. Dicarboxylic acid dibenzoyl hydrazide, hexane dicarboxylic acid dibenzoyl hydrazide, 1,4-cyclohexanedicarboxylic acid dicyclohexylamide, 2,6-naphthalenedicarboxylic acid dianilide, N, N ′, N ″ -tricyclohexyltrimesic acid amide, trimesic acid Tris (t-butylamide), 1,4-cyclohexanedicarboxylic acid dianilide, 2,6-naphthalenedicarboxylic acid dicyclohexylamide, N, N′-dibenzoyl-1,4-diaminocyclohexane, N, N′-dicyclohexane Boniru 1,5-diaminonaphthalene, ethylene bis-stearic acid amide, N, N'-ethylenebis (12-hydroxystearic acid) amide, octane dicarboxylic acid dibenzoyl hydrazide and the like. Of these, N, N ′, N ″ -tricyclohexyltrimesic acid amide, N, N′-ethylenebis (12-hydroxystearic acid) amide, and octanedicarboxylic acid are preferred in view of dispersibility in the resin and heat resistance. Acid dibenzoyl hydrazide is preferred.

  The compounding quantity of a compound (B) needs to be 0.1-5 mass parts when a polylactic acid-type resin is 100 mass parts, and it is preferable that it is 0.1-3 mass parts. If it is less than 0.1 parts by mass, the effect of blending is poor. On the other hand, if it exceeds 5 parts by mass, the effect as a crystal nucleating agent is saturated, which is not economical.

  The aliphatic ester derivative or aliphatic polyether derivative as the compound (C) is preferably one having excellent compatibility with the polylactic acid resin (A) and having a plasticizing effect. That is, the compound (C) is used as a plasticizer for the polylactic acid resin (A).

  Examples of the compound (C) include aliphatic polyvalent carboxylic acid ester derivatives, aliphatic polyhydric alcohol ester derivatives, and aliphatic oxyester derivatives as aliphatic ester derivatives. Examples of the aliphatic polyether derivative include aliphatic polyether polycarboxylic acid ester derivatives. Specific compounds include glycerol diacetomonolaurate, glycerol diacetomonocaprate, polyglycerol acetate, dimethyl adipate, dibutyl adipate, triethylene glycol diacetate, methyl acetylricinoleate, acetyltributyl citrate, polyethylene glycol, dibutyl Diglycol succinate, bis (butyl diglycol) adipate, bis (methyldiglycol) adipate and the like can be mentioned. Among these, glycerin diacetomonolaurate and / or glycerin diacetomonocaprate are preferable in that the crystallization rate of the polylactic acid resin (A) can be further improved.

  The compounding quantity of a compound (C) needs to be 0.5-20 mass parts with respect to 100 mass parts of polylactic acid-type resin (A), and it is preferable that it is 1-10 mass parts. If it is less than 0.5 parts by mass, the effect of blending is poor. On the other hand, if it exceeds 20 parts by mass, not only will there be a problem during melt-kneading extrusion or injection molding, but the object of the present invention of improving heat resistance and shortening the molding cycle cannot be achieved.

  According to the present invention, the compound (B) (C) can be used in combination by combining the compound (B) having a specific structure as described above as a crystal nucleating agent and the compound (C) as a plasticizer. Therefore, the moldability is remarkably improved as compared with the case where each is used alone. This is thought to be because the mechanisms that promote the crystallization of the two differ, and the total crystallization rate at the temperature at which the polylactic acid resin crystallizes due to the unexpected synergistic effect of using both. It is possible to improve the moldability such that the molded product can be taken out without releasing resistance and the molding cycle is shortened.

  In addition, when the compound (B) is used as a crystal nucleating agent and another compound is used without using the compound (C) as a plasticizer, or the compound (B) having a specific structure as described above as a crystal nucleating agent. When other compound is used without using and compound (C) is used as a plasticizer, or other compound is used as crystal nucleating agent without using compound (B) having a specific structure as described above In addition, as compared with the case where the compound (C) is not used as a plasticizer and other compounds are used, the molding cycle can be shortened and the moldability can be improved.

  In order to further improve the molding cycle by crosslinking the polylactic acid resin (A), the polylactic acid resin composition of the present invention may contain a (meth) acrylic acid ester compound (D) as a crosslinking agent. Good. As the (meth) acrylic acid ester compound (D), the reactivity with the polylactic acid resin (A) is high, the monomer hardly remains, and the resin is less colored, so that two or more ( A compound having a (meth) acrylic group or having one or more (meth) acrylic groups and one or more glycidyl groups or vinyl groups in the molecule is preferred. Specific compounds include glycidyl methacrylate, glycidyl acrylate, glycerol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, allyloxy polyethylene glycol monoacrylate, allyloxy polyethylene glycol monomethacrylate, polyethylene glycol dimethacrylate, polyethylene glycol. Diacrylate, polypropylene glycol dimethacrylate, polypropylene glycol diacrylate, polytetramethylene glycol dimethacrylate, or a copolymer in which the alkylene glycol portion thereof has an alkylene chain of various lengths may be used, and butanediol methacrylate or butanediol acrylate. Etc. Of these, polyethylene glycol dimethacrylate, polypropylene glycol dimethacrylate, and the like are preferable because of the reactivity with the polylactic acid resin (A).

  The amount of the (meth) acrylic acid ester compound (D) is preferably 0.01 to 20 parts by mass, and 0.05 to 10 parts by mass with respect to 100 parts by mass of the polylactic acid resin (A). More preferably, it is 0.1 to 5 parts by mass. If there is no particular problem in operability, it can be used in excess of 20 parts by mass.

  In this invention, when mix | blending (meth) acrylic acid ester compound (D), it is preferable to add a peroxide (E) as a reaction aid simultaneously. As the peroxide (E), an organic peroxide having good dispersibility in the resin is preferable, and specifically, benzoyl peroxide, bis (butylperoxy) trimethylcyclohexane, bis (butylperoxy) methylcyclohexane. Dodecane, butylbis (butylperoxy) valerate, dicumyl peroxide, butylperoxybenzoate, dibutyl peroxide, bis (butylperoxy) diisopropylbenzene, dimethyldi (butylperoxy) hexane, dimethyldi (butylperoxy) hexyne, butyl Examples include peroxycumene. It is preferable that the compounding quantity of a peroxide (E) is 0.1-20 mass parts with respect to 100 mass parts of polylactic acid-type resin, and it is more preferable that it is 0.1-10 mass parts. Even if it exceeds 20 mass parts, it can be used, but it is not necessarily economical. In addition, since such a peroxide (E) decomposes | disassembles at the time of mixing with resin, even if it is used at the time of a mixing | blending, it may not be contained in the obtained resin composition.

  In the present invention, examples of means for blending other various blending components with the polylactic acid resin (A) include a melt kneading method using a general-purpose extruder. In order to improve the kneading state, it is preferable to use a twin screw extruder. The kneading temperature is preferably in the range of (melting point of polylactic acid resin (A) + 5 ° C.) to (melting point of polylactic acid resin (A) + 100 ° C.), and the kneading time is 20 seconds to 30 minutes. Is preferred. If the temperature is lower than this range or if the kneading is performed for a short time, the degree of kneading and the reaction itself may be insufficient, and conversely, the temperature may be higher than this range or the kneading may be performed for a long time. In some cases, the resin may be decomposed or colored. In blending, the compound (C) used as a plasticizer and the polylactic acid resin are preferably added simultaneously from the top feeder of the extruder so as to be sufficiently compatible. The method for adding the compound (B) is not particularly limited, but can be added from the hopper of the extruder, or can be added in the middle of kneading using a side feeder. Moreover, it can also be used by diluting with a base resin at the time of shaping | molding by processing glass fiber in a masterbatch.

  The (meth) acrylic acid ester compound (D) as a crosslinking agent and the peroxide (E) as a crosslinking assistant are sufficiently composed of a polylactic acid resin (A) and a compound (C) as a plasticizer. Since it is preferable to add and react when it is melted and in a molten state, it is preferable to side feed from the barrel of the extruder. Thus, as a preferable method when side-feeding the (meth) acrylate compound (D) and the peroxide (E), the (meth) acrylate compound (D) and the peroxide (E) are used as a medium. There is a method of dissolving or dispersing and pouring into a kneader, and in this way, operability can be remarkably improved. That is, during the melt kneading of the polylactic acid resin (A), the compound (C) as a plasticizer and the peroxide (E), a solution or dispersion of the (meth) acrylate compound (D) is injected. Or a solution or dispersion of (meth) acrylic acid ester compound (D) and peroxide (E) during melt-kneading of polylactic acid resin (A) and compound (C) as a plasticizer. Or can be melt-kneaded.

  In the biodegradable polyester resin of the present invention, pigments, heat stabilizers, antioxidants, weathering agents, flame retardants, lubricants, mold release agents, antistatic agents, fillers, etc. Can be added. Examples of heat stabilizers and antioxidants include hindered phenols, phosphorus compounds, hindered amines, sulfur compounds, copper compounds, alkali metal halides, and the like. As the flame retardant, a halogen-based flame retardant, a phosphorus-based flame retardant, and an inorganic flame retardant can be used. However, in consideration of the environment, it is desirable to use a non-halogen flame retardant. Non-halogen flame retardants include phosphorus flame retardants, hydrated metal compounds (aluminum hydroxide and magnesium hydroxide), nitrogen-containing compounds (melamine and guanidine), and inorganic compounds (borate and molybdenum compounds). It is done. Examples of the filler include inorganic fillers and organic fillers. Among these, as the inorganic filler, talc, calcium carbonate, zinc carbonate, wollastonite, silica, alumina, magnesium oxide, calcium silicate, sodium aluminate, calcium aluminate, sodium aluminosilicate, magnesium silicate, glass balloon, Examples thereof include carbon black, zinc oxide, antimony trioxide, zeolite, hydrotalcite, metal fiber, metal whisker, ceramic whisker, potassium titanate, boron nitride, graphite, glass fiber, and carbon fiber. Examples of the organic filler include naturally occurring polymers such as starch, cellulose fine particles, wood flour, okara, fir shell, bran, and modified products thereof. In addition, the method of mixing these with the polylactic acid-type resin composition of this invention is not specifically limited.

  The polylactic acid-based resin composition of the present invention is formed into various molded bodies by injection molding, blow molding, extrusion molding, inflation molding, and molding methods such as vacuum molding, pressure molding, and vacuum / pressure molding after sheet processing. Can do. In particular, an injection molding method is preferable, and in addition to a general injection molding method, gas injection molding, injection press molding, or the like can be employed. If an example of the injection molding conditions suitable for the polylactic acid-type resin composition of this invention is given, cylinder temperature will be more than melting | fusing point Tm or flow start temperature of a resin composition, Preferably it is 190-280 degreeC, More preferably, it is 210-270 degreeC. It is appropriate that the mold temperature is not more than (the glass transition temperature Tg of the resin composition Tg-20 ° C.) or less. If the molding temperature is too low, the operability becomes unstable, such as defective filling in the molded product, and overload tends to occur. Conversely, if the molding temperature is too high, the resin composition decomposes and the resulting molded product Problems such as reduction in strength and coloring are likely to occur.

  The polylactic acid resin composition of the present invention can enhance its heat resistance by promoting crystallization. As a method for promoting this crystallization, for example, devising cooling conditions in the mold at the time of injection molding. In that case, it is preferable that the mold temperature is maintained at (Tg + 20 ° C.) or more and (Tm−20 ° C.) or less for a predetermined time, and then cooled to Tg or less. In addition, crystallization can be promoted after molding, and as a method therefor, it is preferable to directly cool to Tg or lower and then heat-treat again at Tg or higher and (Tm−20 ° C.) or lower.

  Specific examples of molded products include: resin parts for electrical appliances such as various housings; agricultural materials such as containers and cultivation containers; resin parts for agricultural machinery: resin parts for fishery business such as floats and processed fishery products containers; dishes; Tableware and food containers such as cups and spoons; Medical resin parts such as syringes and drip containers; Resin parts for drains, fences, storage boxes, construction switchboards, etc .; Cooler boxes, fan fans, toys Resin parts for miscellaneous goods such as leisure; automotive resin parts such as bumpers, instrument panels and door trims. Moreover, it can also be set as extrusion molded articles, such as a film, a sheet | seat, and a pipe, and a hollow molded article.

Hereinafter, the present invention will be described more specifically with reference to examples.
1. Evaluation Items The measurement methods of the respective items used for the evaluation of the resin compositions of the following examples and comparative examples are as follows.
(1) Melt flow rate (MFR):
According to JIS standard K-7210 (test condition 4), it measured at 190 degreeC and the load 21.2N.

(2) Impact resistance: Measured according to Charpy impact strength ISO 179.

(3) Bending strength:
Measured according to ISO 178.

(4) DTUL (° C):
Based on ISO 75, the heat distortion temperature was measured with a load of 0.45 MPa.

(5) Moldability: Molding cycle A molding test of an ISO dumbbell-shaped test piece was performed with an injection molding machine (manufactured by Toshiba, model number: IS-80G). That is, under the conditions of a molding temperature of 190 ° C. and a mold temperature of 100 ° C., the cooling time after filling the mold with the resin was gradually extended to evaluate the molding cycle (seconds) at which the mold release was good. The molding cycle is preferably 80 seconds or less from the viewpoint of economy.

(6) Formability: Low burrs The burrs of the molded specimen obtained by the molding test of (5) above were visually observed and evaluated according to the following three-stage criteria.

○: The burr is small.
Δ: Burr is slightly large (close to ○).
X: The burr is very large.

2. Raw material (1) Polylactic acid resin (A)
a. Polylactic acid resin (manufactured by Cargill Dow, trade name: NatureWorks, product number: 6201DK, MFR: 10 g / 10 min, melting point: 168 ° C. (hereinafter abbreviated as “PLA”))
b. Polylactic acid copolymer (manufactured by Dainippon Ink Co., Ltd., product name: Puramate PD-150, a biodegradable polyester (hereinafter referred to as “PD-”) containing 50% by mass of a polylactic acid component and the other component being an aliphatic polyester. 150 ”)))

(2) Compound (B)
a. N, N′-ethylenebis (12-hydroxystearic acid) amide (manufactured by Ito Oil Co., Ltd. (hereinafter abbreviated as “EBHSA”))
b. N, N ′, N ″ -tricyclohexyltrimesic acid amide (manufactured by Shin Nippon Rika Co., Ltd., product name: NJester TF-1 (hereinafter abbreviated as “TF-1”))
c. Octanedicarboxylic acid dibenzoyl hydrazide (manufactured by ADEKA, product name: T-1287N (hereinafter abbreviated as “T-1287”))

(3) Compound (C)
a. Glycerin diacetomonocaprate (manufactured by Riken Vitamin Co., Ltd., product name: PL-019 (hereinafter abbreviated as “PL-019”))
b. Glycerin diacetomonolaurate (manufactured by Riken Vitamin Co., Ltd., product name: PL-014 (hereinafter abbreviated as “PL-014”))

(4) Methacrylate compound (D)
a. Polyethylene glycol dimethacrylate (manufactured by NOF Corporation, product name: BLEMMER PDE-50 (hereinafter abbreviated as “EGDM”))

(5) Peroxide (E)
a. Di-t-butyl peroxide (manufactured by NOF Corporation, product name: perbutyl D (hereinafter abbreviated as “PBD”))

(6) Inorganic crystal nucleating agent a. Synthetic fluorine mica in which interlayer ions are substituted with dihydroxyethylmethyldodecylammonium ions (manufactured by Co-op Chemical Co., Ltd., average particle size: 6.3 μm (hereinafter abbreviated as “MEE”))

(7) Plasticizer a. Di-2-ethylhexyl phthalate (manufactured by J Plus Corporation (hereinafter abbreviated as “DOP”))

Examples 1-14, Comparative Examples 1-15
Using a twin screw extruder (manufactured by Toshiba Machine Co., Ltd., model number: TEM 37BS), from the top feeder, the polylactic acid resin (A) and the compound ( B) and the compound (C) were supplied, and melt kneading extrusion was performed at a processing temperature of 190 ° C. At that time, a glass fiber is injected from the middle of the kneading machine using a pump with a composition shown in “Side Feed Composition” in Tables 1 and 2, and a (meth) acrylic acid ester compound (D) as a crosslinking agent is used. ) And a peroxide (E) as a crosslinking aid. As a medium for preparing the mixed solution, the compound (C) was used in an amount shown in Table 1 and Table 2. Then, the discharged resin was cut into pellets to obtain a resin composition.

Next, the pellets were dried under conditions of 70 ° C. × 8 h in a vacuum dryer, and then dumbbell test pieces were molded with the above-described injection molding machine, and the moldability, bending strength, and impact strength were evaluated.
Further, DTUL was measured using a test piece having a molding cycle of 120 seconds. However, in Comparative Example 1, since the composition did not solidify in a molding cycle of 120 seconds and a dumbbell specimen could not be obtained, molding was performed in a molding cycle of 10 minutes to evaluate moldability and other physical properties. did.

  Tables 1 and 2 summarize the results of various physical property evaluations.

  The resin compositions of Examples 1 to 14 were excellent in molding cycle, bending strength, DTUL, and Charpy impact strength. That is, the mechanical strength, heat resistance, and moldability were excellent. In particular, the resin compositions of Examples 2 to 14 were blended with the methacrylic acid ester compound (D), which is a cross-linking agent for the polylactic acid polymer (A). Compared to the resin composition No. 1, the moldability was excellent. The resin compositions of Example 12 and Example 13 include PD-150 as part of the polylactic acid resin (A), and this PD-150 contains aliphatic polyester in addition to polylactic acid as described above. As a result, the rigidity was reduced while flexibility was imparted. As a result, the bending strength and DTUL were slightly reduced, but the Charpy impact strength was excellent.

  The resin composition of Comparative Example 1 was not blended with the methacrylic acid ester compound (D) which is a cross-linking agent for the polylactic acid polymer (A), but the polylactic acid resin (A) and It was constituted only by the compound (C) and did not contain the compound (B). For this reason, the methacrylic acid ester compound (D), that is, the side feed composition was not blended in the same manner, but the molding cycle and DTUL were inferior compared with the resin composition of Example 1 containing the compound (B). .

  The resin composition of Comparative Example 2 was not blended with the methacrylic acid ester compound (D) which is a cross-linking agent for the polylactic acid polymer (A), but the polylactic acid resin (A) and Although compound (B) was included, compound (C) was not included. For this reason, the methacrylic acid ester compound (D), that is, the side feed composition was not blended in the same manner, but the molding cycle was inferior to that of the resin composition of Example 1 containing the compound (C).

  Although the resin composition of Comparative Example 3 was blended with the side feed composition, it did not contain the compound (B), and the resin composition of Comparative Example 10 contained the compound (B). Since the blending amount was below the range of the present invention, the molding cycle was inferior compared with Examples 2 to 13 in which the side feed composition was blended under the same conditions and the compound (B) within the range of the present invention was blended. Met.

  Since the resin compositions of Comparative Examples 4, 5, and 6 were compounded with the side feed composition but did not contain the compound (C), the compound of the side feed composition was compounded under the same conditions and the compound (C). Compared to Examples 2, 5, and 8 containing No. 1, the molding cycle was inferior.

  Since the compounding quantity of the compound (B) exceeded the range of this invention, the effect as a crystal nucleating agent was saturated and the resin composition of the comparative examples 7, 8, and 9 was not economical. In Comparative Examples 7 and 8, burrs occurred.

Since the compounding quantity of the compound (B) exceeded the range of this invention, the resin composition of the comparative example 10 was inferior in a shaping | molding cycle.
Since the compounding quantity of the compound (C) exceeded the range of this invention, the resin composition of the comparative example 11 was inferior in a molding cycle and DTUL.

Although the resin composition of Comparative Example 12 contained the compound (C), the blending amount was below the range of the present invention, so that the molding cycle was inferior.
Since the resin composition of Comparative Example 13 used the inorganic crystal nucleating agent MEE instead of the compound (B), the resin composition of Comparative Example 14 contained the plasticizer DOP instead of the compound (C). In addition, since the resin compound of Comparative Example 15 used the inorganic crystal nucleating agent MEE instead of the compound (B) and the plasticizer DOP instead of the compound (C), Was also inferior in the molding cycle.

Claims (6)

With respect to 100 parts by mass of the polylactic acid-based resin (A), 0.1 to 5 parts by mass of one or more compounds (B) represented by the following general formulas (1) to (3) and an aliphatic ester derivative or A resin composition comprising 0.5 to 20 parts by mass of one or more compounds (C) selected from aliphatic polyether derivatives.
R ^1- (CONH-R ² ) a (1)
[Wherein, R ¹ represents a saturated or unsaturated aliphatic residue, saturated or unsaturated alicyclic acid residue or aromatic residue having 2 to 30 carbon atoms. R ² is an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 2 to 18 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, a cycloalkenyl group having 3 to 12 carbon atoms, a phenyl group, a naphthyl group, or an anthryl group. Represents a group represented by formula (a), formula (b), formula (c) or formula (d). a shows the integer of 2-6. ]

^{R 9 - (NHCO-R 10} ) f (2)
[Wherein R ⁹ represents a saturated or unsaturated aliphatic residue, unsaturated alicyclic residue or aromatic residue having 2 to 30 carbon atoms. R ¹⁰ has the same meaning as R ² described above. f shows the integer of 2-6. ]
^{R 11 - (CONHNHCO-R 12} ) h (3)
[Wherein R ¹¹ represents a saturated or unsaturated aliphatic residue, unsaturated alicyclic residue or aromatic residue having 2 to 30 carbon atoms. R ¹² has the same meaning as R ² described above. h represents an integer of 2 to 6. ]   The polylactic acid resin (A) is 0.01 to 20 parts by mass of the (meth) acrylic acid ester compound (D) and 0.1 to 20 peroxides (E) with respect to 100 parts by mass of the polylactic acid resin. 2. The resin composition according to claim 1, wherein the resin composition is a cross-linked polylactic acid resin obtained from a raw material blended with parts by mass.   The polylactic acid resin (A) is (i) polylactic acid, or (ii) a mixture of polylactic acid and a biodegradable polyester obtained by copolymerizing a lactic acid component. Or the resin composition of 2.   Compound (B) is N, N′-ethylenebis (12-hydroxystearic acid) amide and / or N, N ′, N ″ -tricyclohexyltrimesic acid amide and / or octanedicarboxylic acid diester. The resin composition according to any one of claims 1 to 3, wherein the resin composition is benzoyl hydrazide.   The resin composition according to any one of claims 1 to 4, wherein the compound (C) is glycerin diacetomonocaprate and / or glycerin diacetomonolaurate.   6. A molded article obtained by molding the resin composition according to any one of claims 1 to 5.