JP2009185244A - Resin composition and molded article obtained by molding the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an environmentally friendly, inexpensive resin composition which is excellent in heat resistance and moldability and comprises a polylactic acid resin and a polyolefin resin. <P>SOLUTION: The resin composition comprises the polylactic acid resin (A) and the polyolefin resin (B) in a mass ratio (A/B) of from 10/90 to 99/1, provided that the D-form content of the polylactic acid resin (A) is ≤0.6% or ≥99.4%. The resin composition further comprises a crystal nucleator (D). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a composition comprising a polylactic acid resin and a polyolefin resin that promote crystallization.

  Generally, as a raw material for molding, polypropylene resin (PP), acrylonitrile-butadiene-styrene resin (ABS), polyamide resin (PA6, PA66 etc.), polyester resin (PET, PBT etc.), polycarbonate resin (PC) etc. in use. Molded articles made from such resins are excellent in moldability and mechanical strength, but when discarded, they increase the amount of dust and are hardly decomposed in the natural environment. It remains in the ground semipermanently.

Therefore, in recent years, biodegradable polyester resins have attracted attention from the viewpoint of environmental conservation. Among them, polylactic acid, polyethylene succinate, polybutylene succinate and the like are low in cost and highly useful because they can be mass-produced.
In particular, polylactic acid has already been industrially produced from plants such as corn and sweet potato as raw materials, and even if incinerated after use, considering the carbon dioxide absorbed during the growth of these plants, the carbon balance is neutral. Therefore, it is considered as a resin with a low impact on the global environment.

However, polylactic acid has such advantages, but it is hard and brittle, so it has a problem that its impact strength is insufficient and it is susceptible to hydrolysis, so durability (hydrolysis resistance) is not sufficient. . Moreover, although melting | fusing point is comparatively high, since glass transition temperature (Tg) is low, there also exists a problem that heat resistance is insufficient. On the other hand, in order to increase heat resistance, it is necessary to sufficiently increase crystallization. For example, in injection molding, it can be controlled by setting conditions such as mold temperature and molding cycle time. However, in order to actually increase crystallization, it is necessary to make the mold temperature relatively high, and accordingly, the molding cycle time has to be made relatively long. Therefore, there is a problem that productivity or operability is lowered.
In addition, polyethylene succinate, polybutylene succinate, polyglycolic acid and the like, which are other biodegradable aliphatic polyester resins other than polylactic acid, cannot be said to have sufficient heat resistance, impact resistance, and durability.

  A composition composed of 100% biodegradable aliphatic polyester resin is considered to be difficult to disseminate alone because it is subject to physical properties and production limitations when used as a molding material as described above. It has become. Moreover, even if other non-biodegradable resins are mixed with the biodegradable aliphatic polyester resin, if the biodegradable aliphatic polyester resin is a plant-derived resin such as polylactic acid, it is widely used. As a result, the use of petroleum-derived resins is reduced, and as a result, it is possible to contribute to the saving of petroleum resources. And as resin mixed with polylactic acid, polyolefin resin is considered to be preferable from the viewpoints of spread and cost, and the environmental load during production is small.

  By the way, in order to accelerate the crystallization of polylactic acid itself, Patent Document 1 includes a specific carboxylic acid amide / ester compound, Patent Document 2 includes a tricyclohexyltrimesic acid amide compound, and Patent Document 3 includes an ethylenebishydroxystearic acid compound. It has been proposed that amide blending is cross-linked by methacrylic acid ester in Patent Document 4, cross-linking by isocyanate in Patent Document 5, and L-form content is 95% or more in Patent Document 6. The effect is insufficient. In addition, the mold temperature at the time of molding needs to be a high temperature of about 100 ° C., which is considerably higher than the normal molding of polyolefin resin. Therefore, when mixed with polyolefin resin, the excellent moldability of polyolefin resin itself It is difficult to make use of

On the other hand, as an alloy technology for polylactic acid and polyolefin resin, Patent Document 7 proposes to use polypropylene having a high temperature-falling crystallization temperature, but the deflection temperature under load of the molded product itself has not been evaluated. Patent Document 8 proposes to use a high molecular weight polypropylene and an inorganic filler, but the mold temperature is as low as 30 ° C., and heat resistance imparted by the progress of crystallization of polylactic acid is considered. Absent. Furthermore, Patent Document 9 proposes to use a polylactic acid having a D / L ratio in a specific range, but in order to obtain a DTUL (small load) sufficiently exceeding 90 ° C., it is expensive to half the polylactic acid blending amount. Poly-D-lactic acid had to be used, and there was a big problem in terms of cost.
JP 2006-137397 A JP 2006-328163 A JP 2003-226801 A JP 2003-128901 A JP 2002-003709 A JP 2007-051274 A JP 2007-177038 A JP 2007-145912 A JP 2007-009008 A

  An object of the present invention is to provide a resin composition containing a polylactic acid resin and a polyolefin resin, which solves the above-described problems, has a low burden on the global environment, is inexpensive, and has excellent heat resistance and moldability. That is.

As a result of intensive studies to solve such problems, the present inventors used a polylactic acid resin having a low or high D-form content as the polylactic acid resin. The present inventors have found that a resin composition containing a solution to the above problem has reached the present invention.
That is, the gist of the present invention is as follows.
(1) A resin composition containing a polylactic acid resin (A) and a polyolefin resin (B), wherein the mass ratio (A / B) of (A) and (B) is 10/90 to 99/1. A D-form content of the polylactic acid resin (A) is 0.6% or less, or 99.4% or more.
(2) The resin composition as described in (1), further containing an inorganic filler (C) and having a content of 0.5 to 50% by mass.
(3) The resin composition according to (2), wherein the inorganic filler (C) is talc.
(4) The resin composition according to any one of (1) to (3), wherein the polylactic acid resin (A) is melt kneaded together with a (meth) acrylic acid ester compound and a peroxide. .
(5) The resin composition according to any one of (1) to (4), further comprising a crystal nucleating agent (D) and having a content of 0.03 to 5% by mass.
(6) The crystal nucleating agent (D) is at least one selected from organic amide compounds, organic hydrazide compounds, carboxylic acid ester compounds, organic sulfonates, phthalocyanine compounds, melamine compounds, and organic phosphonates. (5) The resin composition as described in the above.
(7) The crystal nucleating agent (D) is N, N ′, N ″ -tricyclohexyltrimesic acid amide, N, N′-ethylenebis12 hydroxystearic acid amide, octanedicarboxylic acid dibenzoyl hydrazide, 5 sulfoisophthalic acid The resin composition according to (5), which is at least one selected from dimethyl metal salts.
(8) The resin composition according to any one of (1) to (7), further comprising a compatibilizer (E), the content of which is 0.05 to 30% by mass.
(9) The resin composition as described in (8), wherein the compatibilizer (E) is a block copolymer containing a styrene monomer and an olefin monomer.
(10) A molded article obtained by molding the resin composition according to any one of (1) to (9).

  According to the present invention, a resin composition containing a polylactic acid resin and a polyolefin resin, wherein a polylactic acid resin having a low or high D-form content is used as the polylactic acid resin. The crystallization speed is increased, the molding cycle time at the time of injection molding can be shortened, and the heat resistance is further improved. This makes it possible to greatly expand the range of use of the polylactic acid resin having a low environmental load, and the industrial utility value of the present invention is extremely high.

Hereinafter, the present invention will be described in detail.
The resin composition of the present invention is a resin composition containing a polylactic acid resin (A) and a polyolefin resin (B), and the D-form content of the polylactic acid resin (A) is 0.6% or less. Or 99.4% or more.

The polylactic acid resin (A) constituting the resin composition of the present invention must have a D-form content of 0.6% or less, or 99.4% or more, and 0.3% or less. Or 99.7% or more. When a polylactic acid resin having a D-form content outside this range is used as the polylactic acid resin (A), when the mold temperature during molding is set lower than 90 to 120 ° C., a molded article having heat resistance is obtained. I can't.
In the present invention, when a polylactic acid resin (A) having a D-form content of 0.6% or less is used, a polylactic acid resin having a D-form content of less than 0.08% is obtained or produced. In the present invention, a polylactic acid resin having a D-form content of less than 0.08% can also be used. Similarly, when using a polylactic acid resin (A) having a D-form content of 99.4% or more, obtaining or producing a polylactic acid resin having a D-form content exceeding 99.92% In the present invention, a polylactic acid resin having a D-form content exceeding 99.92% can also be used.

  In the present invention, the D-form content of the polylactic acid resin (A) is a ratio (%) occupied by the D lactic acid unit in the total lactic acid units constituting the polylactic acid resin (A). Therefore, for example, in the case of a polylactic acid resin (A) having a D-form content of 0.6%, the polylactic acid resin (A) has a D-lactic acid unit occupying a ratio of 0.6%, and an L-lactic acid unit is included. The share is 99.4%.

  In the present invention, as described later, the D-form content of the polylactic acid resin (A) is such that L lactic acid obtained by decomposing the polylactic acid resin (A) and D lactic acid are all methyl esterified, and the methyl of L lactic acid is obtained. It calculated by the method of analyzing ester and methyl ester of D lactic acid with a gas chromatography analyzer.

As polylactic acid resin (A) used for this invention, polylactic acid resin of the range which D body content prescribes | regulates by this invention among various commercially available polylactic acid resins can be used.
Moreover, as a polylactic acid resin (A), among lactide which is a cyclic dimer of lactic acid, L-lactide having a sufficiently low D-form content or D-lactide having a sufficiently low L-form content is used as a raw material. The produced one can also be used.
Furthermore, in this invention, you may combine 2 or more types of polylactic acid resin as a polylactic acid resin (A). In this case, a polylactic acid resin having a D-form content outside the range specified in the present invention, for example, a polylactic acid resin having a D-form content exceeding 0.6% may be used in combination. And the polylactic acid resin (A) obtained by combining the polylactic acid resin satisfying the D-form content specified in the present invention, the D-form content may be 0.6% or less. Similarly, as a polylactic acid resin constituting the polylactic acid resin (A), a polylactic acid resin having a D-form content of less than 99.4% may be used in combination. In the polylactic acid resin (A) obtained in combination, The D body content should just be 99.4% or more.

  In the present invention, the polylactic acid resin (A) has a melt flow rate (MFR) at 190 ° C. and a load of 2.16 kg (value according to JIS standard K-7210 (test condition 4)) of 0.1 to 50 g / 10 min. It is preferable that it is 0.2 to 20 g / 10 min, more preferably 0.5 to 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 at the time of molding increases, and the operability may be lowered.

  The polylactic acid resin (A) is produced by a known melt polymerization method or by further using a solid phase polymerization method. As a method for adjusting the melt flow rate of the polylactic acid resin (A) to a predetermined range, when the melt flow rate is too large, a small amount of chain extender, for example, a diisocyanate compound, a bisoxazoline compound, an epoxy compound, The method of increasing the molecular weight of resin using an acid anhydride etc. 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 resin composition of the present invention, the polylactic acid resin (A) is preferably melt kneaded together with a (meth) acrylic acid ester compound and a peroxide. By melt-kneading the polylactic acid resin (A) together with these, crystallization can be promoted and heat resistance can be improved.

As a specific compound of the (meth) acrylic acid ester compound, the reactivity with the polylactic acid resin (A) is high, the monomer hardly remains, the toxicity is low, and the resin is less colored. A compound having two or more (meth) acryl groups, or one or more (meth) acryl groups and one or more glycidyl groups or vinyl groups is preferred.
Specific examples of (meth) acrylic acid ester compounds include glycidyl methacrylate, glycidyl acrylate, glycerol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, allyloxy polyethylene glycol monoacrylate, allyloxy (poly) ethylene glycol monomethacrylate. , (Poly) ethylene glycol dimethacrylate, (poly) ethylene glycol diacrylate, (poly) propylene glycol dimethacrylate, (poly) propylene glycol diacrylate, (poly) tetramethylene glycol dimethacrylate, or these alkylene glycol moieties Copolymers of alkylenes of various lengths, butanediol methacrylate, butanediol active Rate, and the like.

  The addition amount of the (meth) acrylic acid ester compound is preferably 0.01 to 20 parts by mass and more preferably 0.05 to 1 part by mass with respect to 100 parts by mass of the polylactic acid resin (A). preferable. If the addition amount is less than 0.01 parts by mass, the desired heat resistance cannot be obtained, and if the addition amount exceeds 20 parts by mass, the operability during kneading decreases.

  The peroxide is melt kneaded for the purpose of accelerating the reaction between the (meth) acrylic acid ester compound and the polylactic acid resin (A), and achieving crystallization promotion and heat resistance improvement more effectively. Specific examples include benzoyl peroxide, bis (butylperoxy) trimethylcyclohexane, bis (butylperoxy) cyclododecane, butylbis (butylperoxy) valerate, dicumyl peroxide, butylperoxybenzoate, dibutyl peroxide Bis (butylperoxy) diisopropylbenzene, dimethyldi (butylperoxy) hexane, dimethyldi (butylperoxy) hexyne, butylperoxycumene and the like.

  The added amount of the peroxide is preferably 0.02 to 20 parts by mass, and more preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the polylactic acid resin (A). If the addition amount is less than 0.02 parts by mass, the intended effect cannot be obtained, and if the addition amount exceeds 20 parts by mass, the operability during kneading may decrease.

  Examples of the polyolefin resin (B) used in the present invention include polyethylene, polypropylene, poly-4-methylpentene-1, polybutene, polyisobutylene, and cycloolefin resin. Of these, polypropylene and polyethylene are preferable, and polypropylene is most preferable. In terms of heat resistance and durability, isotactic polypropylene is preferable. The polyolefin resin may be three-dimensionally cross-linked with an organic peroxide, partially chlorinated, or co-polymerized with vinyl acetate, acrylic acid, methacrylic acid, maleic anhydride, etc. They can be combined.

  The molecular weight of the polyolefin resin (B) is not particularly limited, but for the melt flow rate as an index thereof, for example, in the case of polypropylene resin, the value at 230 ° C. and a load of 2.16 kg is 0.1 to 70 g / 10 min. If it is in the range, it can be preferably used. More preferably, it is the range of 0.5-50 g / 10min.

In the resin composition of the present invention, as a mixing ratio of the polylactic acid resin (A) and the polyolefin resin (B), the mass ratio (A / B) needs to be 10/90 to 99/1. 29/71 to 91/9, and more preferably 29/71 to 83/17.
When the blending ratio of the polyolefin resin (B) is less than 1% by mass, the effect of adding the polyolefin resin (B) is not seen, and the impact strength and heat resistance are not improved sufficiently. Moreover, when the ratio of polyolefin resin (B) exceeds 90 mass%, the ratio of polylactic acid resin (A) is too small, and it becomes difficult to say that it is an environment-friendly resin composition.

The resin composition of the present invention promotes crystallization of the polylactic acid resin (A) and the polyolefin resin (B), improves workability when taking out from the mold, and further improves the heat resistance of the molded product. For the purpose of, it is preferable to contain an inorganic filler (C).
Examples of the inorganic filler (C) include talc, mica, silica, calcium carbonate, zinc carbonate, wollastonite, alumina, magnesium oxide, calcium silicate, sodium aluminate, calcium aluminate, sodium aluminosilicate, magnesium silicate. , Glass balloon, carbon black, zinc oxide, antimony trioxide, zeolite, bentonite, hydrotalcite, metal fiber, metal whisker, ceramic whisker, titanium oxide, potassium titanate, boron nitride, graphite, glass fiber, carbon fiber, smectite Swellable layered silicates such as vermiculite and swellable fluorinated mica. Of these, talc is most preferable. As a commercially available thing, Hayashi Kasei talc MW-HST etc. are mentioned, for example.
These inorganic fillers (C) may be added alone or in combination of two or more.
In the resin composition of the present invention, the content of the inorganic filler (C) is preferably 0.5 to 50% by mass. If the content of the inorganic filler (C) exceeds 50% by mass, the kneading property may be inferior, and if it is less than 0.5% by mass, the desired effect cannot be obtained.

The resin composition of the present invention preferably contains a crystal nucleating agent (D) for the purpose of promoting crystallization of the polylactic acid resin (A) and the polyolefin resin (B) and improving heat resistance.
The compound used as the crystal nucleating agent (D) is not particularly limited, and various compounds can be used. Examples of commercially available products include WX-1 manufactured by Kawaken Fine Chemical Co., Ltd., TF-1 manufactured by Shin Nippon Chemical Co., Ltd., T-1287N manufactured by Adeka Company, and master batch KX238B manufactured by Toyota. From the viewpoint of the effect of promoting crystallization, one or more selected from organic amide compounds, organic hydrazide compounds, carboxylic acid ester compounds, organic sulfonates, phthalocyanine compounds, melamine compounds, and organic phosphonates are preferable.

As the organic amide compound, compounds represented by the following general formulas (1) and (2) are preferable, and as the organic hydrazide compound, a compound represented by the general formula (3) is preferable.
R1- (CONH-R2) a (1)
[Wherein R 1 represents a saturated or unsaturated aliphatic chain having 2 to 30 carbon atoms, a saturated or unsaturated aliphatic ring, or an aromatic ring. R2 represents 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 or a cycloalkenyl group, a phenyl group, a naphthyl group, an anthryl group, or a group represented by the formula (a) to (D) represents a group represented by any one, and one or more hydrogen atoms may be substituted with a hydroxyl group. a represents an integer of 2 to 6. ]
[Wherein R3 is an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 2 to 18 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, a cycloalkyl group having 3 to 18 carbon atoms, a phenyl group, or a halogen atom. Represents. l represents an integer of 1 to 5. ]
[Wherein, R 4 represents a linear or branched alkylene group having 1 to 4 carbon atoms. R5 has the same meaning as R3. m represents an integer of 0 to 5. ]
[Wherein, R6 has the same meaning as R3 described above. n represents an integer of 1 to 5. ]
[Wherein, R7 has the same meaning as R4, and R8 has the same meaning as R3. o represents an integer of 0-6. ]
R9- (NHCO-R10) f (2)
[Wherein R 9 represents a saturated or unsaturated fatty chain having 2 to 30 carbon atoms, an unsaturated alicyclic ring, or an aromatic ring. R10 has the same meaning as R2. f represents an integer of 2-6. ]
R11- (CONHNHCO-R12) h (3)
[Wherein R11 represents a saturated or unsaturated fatty chain having 2 to 30 carbon atoms, an unsaturated alicyclic ring, or an aromatic ring. R12 has the same meaning as R2. h represents an integer of 2 to 6. ]

  Specific compounds represented by the general formulas (1) to (3) include, for example, hexamethylene bis-9, 10-dihydroxy stearic acid bisamide, p-xylylene bis-9, 10 dihydroxy stearic acid amide, decanedicarboxylic acid. Dibenzoylhydrazide, hexanedicarboxylic acid dibenzoylhydrazide, 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'-dicyclohexanecarbonyl-1, - 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, octanedicarboxylic acid are preferred in view of dispersibility in the resin and heat resistance. Dibenzoyl hydrazide is preferable, and N, N ′, N ″ -tricyclohexyltrimesic acid amide and N, N′-ethylenebis (12-hydroxystearic acid) amide are particularly preferable.

  As the carboxylic acid ester compound, various compounds can be used. For example, aliphatic bishydroxycarboxylic acid ester is preferable.

  As the organic sulfonate, various compounds such as sulfoisophthalate can be used, and among them, dimethyl metal salt of 5-sulfoisophthalic acid is preferable from the viewpoint of the effect of promoting crystallization. Furthermore, barium salt, calcium salt, strontium salt, potassium salt, rubidium salt, sodium salt and the like are preferable.

Although various compounds can be used as the phthalocyanine compound, it is preferable to use a transition metal complex, and among them, copper phthalocyanine is preferable from the viewpoint of the crystallization promoting effect.
Various compounds can be used as the melamine compound, but melamine cyanurate is preferably used from the viewpoint of the crystallization promoting effect.
As the organic phosphonate, phenylphosphonate is preferable from the viewpoint of the crystallization promoting effect. Of these, zinc phenylphosphonate is particularly preferred.
As the crystal nucleating agent (D), these may be used alone or in combination of two or more. In addition, you may use together various inorganic type crystal nucleating agents with respect to these organic type crystal nucleating agents (D).

  In the resin composition of the present invention, the content of the crystal nucleating agent (D) is preferably 0.03 to 5% by mass. If the content of the crystal nucleating agent (D) is less than 0.03% by mass, the effect of blending is poor, and adding more than 5% by mass is often economically disadvantageous.

The resin composition of the present invention preferably contains a compatibilizer (E). By containing the compatibilizer (E), the compatibility between the polylactic acid resin (A) and the polypropylene resin (B) is improved, and impact resistance or appearance can be improved.
As the compatibilizing agent (E), any one having a compatibilizing effect can be used. For example, various copolymers can be suitably used. From the viewpoint of the compatibilizing effect, among the copolymers, a block copolymer containing a styrene monomer and an olefin monomer is particularly preferable. Preferred commercially available products include styrene / olefin block copolymer elastomer “Dynalon 8630P” manufactured by JSR Corporation. In addition, an epoxy group-containing polyethylene / acrylic graft copolymer “Modiper A4200” manufactured by NOF Corporation is also a suitable example.
In the resin composition of the present invention, the content of the compatibilizer (E) is preferably 0.05 to 30% by mass. If the content of the compatibilizer (E) is less than 0.05% by mass, the effect of blending is poor, and if it is added in excess of 30% by mass, it is often economically disadvantageous.

  The resin composition of the present invention includes a flame retardant, a pigment, a heat stabilizer, an antioxidant, a vegetable fiber, a weathering agent, a plasticizer, a lubricant, a release agent, an antistatic agent, etc. Can be added. Examples of the flame retardant include condensed phosphate esters from the viewpoint of flame retardancy or durability. Examples of heat stabilizers and antioxidants include hindered phenols, hindered amines, sulfur compounds, copper compounds, alkali metal halides, and the like. Examples of plant fibers include kenaf fibers. Examples of the plasticizer include glycerin diacetomonocaprate, glycerin diacetomonolaurate, and tributyl acetylcitrate. In addition, the method of mixing these with the polyester resin composition of this invention is not specifically limited.

  The resin composition of the present invention can be molded into various molded products by molding methods such as injection molding, blow molding, extrusion molding, inflation molding, inbro, foamed sheet molding, and vacuum molding, pressure molding, and vacuum / pressure molding after sheet processing. It can be. That is, a molded body formed by injection molding, or a film or sheet formed by extrusion molding, a molded body processed from these films or sheets, or a hollow body formed by blow molding, and the hollow body It can be set as the molded object etc. which are processed from.

  In the present invention, it is particularly preferable to adopt an injection molding method, and in addition to a general injection molding method, gas injection molding, injection press molding, and the like can be employed. As an example of injection molding conditions suitable for the resin composition of the present invention, the cylinder temperature is equal to or higher than the melting point or flow start temperature of the resin composition, preferably 170 to 250 ° C, optimally in the range of 170 to 230 ° C, Further, it is appropriate that the mold temperature is not higher than (melting point−40 ° C.) of the resin composition. If the cylinder temperature is too low, the operability becomes unstable or overloading occurs, such as a short circuit in the molded product. Conversely, if the molding temperature is too high, the resin composition decomposes and the resulting molded product Problems such as reduction in strength and coloration are likely to occur, and both may be undesirable.

  The heat resistance of the resin composition of the present invention can be further improved by promoting crystallization during molding. As a method for this purpose, for example, there is a method of promoting crystallization in a mold at the time of injection molding, and in that case, the glass transition temperature of the resin composition is maintained above (melting point−40 ° C.). A method in which the molded product is held for a certain period of time in the mold and then removed from the mold is preferable. Moreover, even if it is a molded article taken out from the mold without taking such a method, crystallization can be promoted by heat treatment again at a glass transition temperature or higher and (melting point −40 ° C.) or lower. it can.

Specific examples of the molded body of the present invention include personal computer casing parts and casings, mobile phone casing parts and casings, other OA equipment casing parts, resin parts for electrical appliances such as connectors; bumpers, instrument panels , Console boxes, garnishes, door trims, ceilings, floors, plastic parts for automobiles such as panels around engines, agricultural materials such as containers and cultivation containers, and plastic parts for agricultural machinery; marine products such as floats and processed fishery products containers Resin parts for use; dishes, food containers such as dishes, cups, and spoons; medical resin parts such as syringes and infusion containers; resin parts for housing, civil engineering, and building materials such as drain materials, fences, storage boxes, and distribution boards for construction; Resin parts for greening materials such as flowerbed bricks and flowerpots; Resin parts for leisure and miscellaneous goods such as cooler boxes, fan fans, toys; ballpoint pens, rulers, clicks Stationery resin parts, etc. and the like.
In addition, the resin composition of the present invention can be formed into an extrusion-molded product such as a film, a sheet or a pipe, or a hollow molded product. Examples include many agricultural multi-films, construction sheets, various blow molded bottles, and the like.

Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited only to the following examples.
The measuring methods used for the evaluation of the following Examples and Comparative Examples are as follows.

(1) D-form content:
About 0.3 g of the polylactic acid resin (A) or the resin composition is added to 6 mL of 1N potassium hydroxide / methanol solution, and after sufficiently stirring at 65 ° C., 450 μL of sulfuric acid is added and stirred at 65 ° C., Polylactic acid was decomposed. 5 mL of this sample, 3 mL of pure water, and 13 mL of methylene chloride were mixed and shaken. After stationary separation, about 1.5 mL of the lower organic layer was collected, filtered through an HPLC disk filter having a pore size of 0.45 μm, and then subjected to GC measurement using HP-6890 Series GC system manufactured by Hewlett Packard. The ratio (%) of the peak area of D-lactic acid methyl ester in the total peak area of lactate methyl ester was calculated, and this was used as the D-form content (%).

(2) Melt flow rate (MFR):
In accordance with JIS K7210, the polylactic acid resin (A) was measured at 190 ° C. and a load of 2.16 kg, and the polyolefin resin (B) was measured at 230 ° C. and a load of 2.16 kg.

(3) Molding cycle time:
At the time of injection molding, when the injection time is constant at a predetermined mold temperature (85 ° C) and the cooling time is changed, the minimum time during which the molded piece is not deformed or the sprue or runner is not torn off is the molding cycle. It was time.

(4) Impact resistance:
Based on ISO179, the Charpy impact strength was measured with a notch. Impact strength is 2.5 kJ / m ² or less x, 2.5 kJ / m ² is exceeded and 3.0 kJ / m ² or less is Δ, 3.0 kJ / m ² is over 4.5 kJ / m ² is A value exceeding 0.5 kJ / m ² was marked as ◎.

(5) Heat resistance:
In accordance with ISO 75, the heat distortion temperature was measured at a load of 0.45 MPa. When the heat distortion temperature was 80 ° C. or lower, x, over 80 ° C. and 90 ° C. or lower were evaluated as Δ, over 90 ° C. and 100 ° C. or lower were evaluated as ◯, and over 100 ° C.

(6) Surface appearance:
The surface of the injection-molded test piece was visually observed. ◎ indicates that there are no defects such as sink marks, blisters, and peeling, and the surface is uniform and clean. A case where there was a defective point such as a sink, swelling or peeling in a very small part was marked with Δ, and a case where there was a defective point such as a sink, swelling or peeling on the surface of the test piece was marked with ×.

(7) Operability:
When kneading and extruding, there is no disorder such as strand breakage, and when the strand can be cut without any problem, the situation is such that the strand is disturbed during kneading and extrusion, or the strand is not solidified and difficult to cut. The case where it occurred was marked with Δ.

The raw materials used in the following examples and comparative examples are as follows.
(1) Polylactic acid resin (A):
“S-12” manufactured by Toyota (L-form 99.9 mol%, D-form 0.1 mol%, MFR = 8)
“6201D” manufactured by Nature Works (L-form 98.6 mol%, D-form 1.4 mol%, MFR = 10)
(2) Polyolefin resin (B):
Polypropylene made by Nippon Polypro Co., Ltd. “NOVATEC BC03C” (MFR = 30)
Polypropylene “Novatec BC6C” manufactured by Nippon Polypro Co., Ltd. (MFR = 2.5)
(3) Inorganic filler (C):
Hayashi Kasei Co., Ltd. talc “MW-HST” (average particle size 2.7 μm)
(4) Crystal nucleating agent (D):
Trimesic acid tricyclohexylamide “TF-1” manufactured by Shin Nippon Chemical Co., Ltd.
(5) (Meth) acrylic acid ester compound:
Ethylene glycol dimethacrylate "Blemmer PDE-50" made by NOF
(6) Peroxide:
Di-t-butyl peroxide "Perbutyl D" made by NOF
(7) Compatibilizer (E):
JSR styrene / olefin block copolymer elastomer “Dynalon 8630P”

Example 1
Using Toshiba Machine's twin-screw kneader TEM-37, 54 parts by mass of polylactic acid resin (A) “S-12”, 41 parts by mass of polyolefin resin (B) “BC03C”, and 1 mass of inorganic filler (C) Part, 1 part by mass of crystal nucleating agent (D) and 3 parts by mass of compatibilizer (E) are dry blended and supplied from a supply hopper, extrusion temperature 190 ° C., die outlet temperature 190 ° C., screw rotation speed 200 rpm The mixture was melt kneaded at a discharge rate of 20 kg / h. The kneaded resin was extruded into strands, cooled in a water bath, and cut into pellets with a pelletizer.
After drying the obtained resin composition pellets, injection molding is performed at a cylinder set temperature of 210 ° C. using an injection molding machine IS-80G manufactured by Toshiba Machine Co., Ltd., and a test for measuring general physical properties at a mold temperature of 85 ° C. A piece (ISO type) was produced. During the preparation of the test piece, the molding cycle was measured. Then, the produced test piece was used for various measurements.

Examples 2-9, Comparative Examples 1-2
Resin as in Example 1 except that the type and amount of polylactic acid resin (A), polyolefin resin (B), inorganic filler (C), crystal nucleating agent (D), and compatibilizing agent (E) were changed. Composition pellets and test pieces were prepared and evaluated.

Example 10
Using Toshiba Machine's twin-screw kneader TEM-37, 55 parts by mass of polylactic acid resin (A) “S-12”, 42 parts by mass of polyolefin resin (B) “BC03C”, and 3 parts by mass of compatibilizer (E) The components were dry blended and supplied from a supply hopper, and melt kneaded at an extrusion temperature of 190 ° C., a die outlet temperature of 190 ° C., a screw rotation speed of 200 rpm, and a discharge rate of 20 kg / h. Further, 0.1 part by mass of (meth) acrylic acid ester compound and 0.2 part by mass of peroxide were supplied into the cylinder. The kneaded resin was extruded into strands, cooled in a water bath, and cut into pellets with a pelletizer.
After drying the obtained resin composition pellets, injection molding is performed at a cylinder set temperature of 210 ° C. using an injection molding machine IS-80G manufactured by Toshiba Machine Co., Ltd., and a test for measuring general physical properties at a mold temperature of 85 ° C. A piece (ISO type) was produced. During the preparation of the test piece, the molding cycle was measured. Then, the produced test piece was used for various measurements.

Example 11
Resin composition pellets and test pieces were prepared in the same manner as in Example 10 except that the amounts of polylactic acid resin (A), polyolefin resin (B), inorganic filler (C), and crystal nucleating agent (D) were changed. evaluated.

  The results of Examples 1 to 11 and Comparative Examples 1 and 2 are collectively shown in Table 1.

In Examples 1 to 11, molded articles having excellent heat resistance and impact resistance were obtained, and the molding cycle time was also good.
Among Examples, in Examples 1 to 3, 5, and 9 to 11, an appropriate amount of inorganic filler (C) and crystal nucleating agent (D) is blended in the resin composition, or polylactic acid resin (A) is used. Since both the (meth) acrylic acid ester compound and the peroxide are melt-kneaded, particularly excellent results were obtained in molding cycle time and heat resistance, and kneading operability was also good.
Among them, in Example 1, since both the inorganic filler (C) and the crystal nucleating agent (D) were blended, extremely excellent results were obtained in the molding cycle time. In Example 11, the inorganic filler (C) and the crystal nucleating agent (D) are blended together, and the polylactic acid resin (A) melts the (meth) acrylic acid ester compound and the peroxide. Due to the kneading, particularly excellent results were obtained in the molding cycle time.
In Examples 1 to 4, since an appropriate amount of the compatibilizer (E) was blended, particularly excellent results were obtained in impact resistance and appearance, and kneading operability was also good.
In Example 7, since the inorganic filler (C) was excessively blended, the strand during kneading tended to be slightly unstable. Moreover, in Example 8, since the compatibilizing agent (E) was excessively blended, the strands during kneading tended to be slightly unstable, and the strands were somewhat difficult to cut.
On the other hand, in Comparative Example 1, since the D-form content of the polylactic acid resin (A) was outside the range specified in the present invention, the heat resistance and the molding cycle time were inferior. In Comparative Example 2, since the blending amount of the polyolefin resin (B) was small, the impact resistance and the heat resistance were inferior, and the cost was disadvantageous.

Claims (10)

A resin composition containing a polylactic acid resin (A) and a polyolefin resin (B), wherein the mass ratio (A / B) of (A) and (B) is 10/90 to 99/1, A resin composition, wherein the D-form content of the lactic acid resin (A) is 0.6% or less, or 99.4% or more. Furthermore, the inorganic filler (C) is contained, and the content thereof is 0.5 to 50% by mass. The resin composition according to claim 2, wherein the inorganic filler (C) is talc. The resin composition according to any one of claims 1 to 3, wherein the polylactic acid resin (A) is melt kneaded together with a (meth) acrylic acid ester compound and a peroxide. The resin composition according to any one of claims 1 to 4, further comprising a crystal nucleating agent (D), the content of which is 0.03 to 5% by mass. The crystal nucleating agent (D) is at least one selected from organic amide compounds, organic hydrazide compounds, carboxylic acid ester compounds, organic sulfonates, phthalocyanine compounds, melamine compounds, and organic phosphonates. The resin composition according to claim 5. Crystal nucleating agent (D) is N, N ′, N ″ -tricyclohexyltrimesic acid amide, N, N′-ethylenebis12hydroxystearic acid amide, octanedicarboxylic acid dibenzoylhydrazide, 5 sulfoisophthalic acid dimethyl metal salt The resin composition according to claim 5, wherein the resin composition is one or more selected from the group consisting of: The resin composition according to any one of claims 1 to 7, further comprising a compatibilizer (E), the content of which is 0.05 to 30% by mass. The resin composition according to claim 8, wherein the compatibilizing agent (E) is a block copolymer containing a styrene monomer and an olefin monomer. The molded object formed by shape | molding the resin composition in any one of Claims 1-9.