JP2008101083A - Flame-retardant polylactic acid resin composition and molded article produced by molding the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flame-retardant polylactic acid resin composition having excellent heat-resistance. <P>SOLUTION: The flame-retardant polylactic acid resin composition is produced by melting and kneading a mixture containing a polylactic acid resin as a main component and further containing 3-30 mass% pentavalent phosphorus compounds wherein the ratio of total carbon atom in the aromatic ring to the molecular weight is ≥60%, 0.01-5 mass% (meth)acrylic acid ester compounds and ≥0.001 mass% peroxides. As an alternative, the flame-retardant polylactic acid resin composition contains a polylactic acid resin as a main component, and further contains 3-30 mass% pentavalent phosphorus compound wherein the ratio of total carbon atom in the aromatic ring to the molecular weight is ≥60%, 0.1-5 mass% organic crystal nucleation agent and 1-10 mass% plasticizer composed of an aliphatic ester derivative and/or an aliphatic polyether derivative. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is a resin composition containing a polylactic acid resin as a main component, and includes a phosphorus compound, a (meth) acrylic acid ester compound, and a peroxide, or a phosphorus compound, an organic crystal nucleating agent, and a plasticizer. The present invention relates to a flame retardant polylactic acid resin composition having excellent heat resistance.

  In general, resins such as polypropylene (PP), ABS (acrylonitrile-butadiene-styrene resin), polyamide (PA6, PA66), polyester (PET, PBT), and polycarbonate (PC) are used as raw materials for molding. However, moldings 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. However, it remains in the ground semipermanently.

  On the other hand, in recent years, biodegradable polyester resins such as polylactic acid have attracted attention from the viewpoint of environmental conservation. Among the biodegradable resins, polylactic acid, polyethylene succinate, polybutylene succinate and the like are inexpensive and are highly useful because they can be mass-produced. Among them, polylactic acid has already been industrially produced from plants such as corn and sweet potato, 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 having a particularly low load on the global environment.

  However, when polylactic acid is used alone for a housing of an electric product or the like, the flame retardancy is insufficient, and there is a safety problem due to its combustibility. In addition, their applications often require heat resistance of at least around 100 ° C. Thus, what has a flame retardance and heat resistance was calculated | required.

  With regard to imparting flame retardancy to polylactic acid, several reports have already been made, such as applying a known flame retardant formulation to polylactic acid.

  For example, in Patent Document 1, an organic filler and a flame retardant are added to polylactic acid resin, and injection molding is performed at a mold temperature of 90 ° C., so that flame retardancy of V-2 to V-0 and 100 ° C. It is described that front and rear deflection temperatures (0.45 MPa) can be obtained. On the other hand, Patent Document 2 describes that by adding a surface-treated hydroxide, flame retardancy and a deflection temperature under load of 50 ° C. or higher (1.8 MPa) can be obtained. Furthermore, Patent Document 3 describes that it is possible to achieve both flame retardancy and storage characteristics by adding a hydrolysis inhibitor in addition to the flame retardant.

  However, in the example described in Patent Document 1, the heat resistance is improved by adding 20% or more of waste paper powder as an organic filler, but it is discolored by heat at the time of kneading or melting during molding. Is inevitable, color adjustment is difficult, and transparency is lost. Moreover, in patent document 2 or patent document 3, the obtained flame retardance is only V-2, and it is still in an insufficient level when used for the said use.

  In addition, Patent Document 4 describes that V-0 can be obtained by using a hydroxide subjected to a surface treatment with a nitric acid compound, and Patent Document 5 also uses a specific flame retardant. The formulation to obtain V-0 is described.

  However, in the example described in Patent Document 4, the evaluation of flame retardancy is evaluated only with a thickness of 3 mm, which is insufficient for applications such as thinner electrical products. Not considered. Moreover, in patent document 5, the petroleum-derived resin component is essential, and an environmental load is large.

  Furthermore, Patent Document 6 describes that V-0 can be obtained by using a magnesium salt and polyphenol in combination with a phosphorus-based flame retardant, and Patent Document 7 discloses that V-0 can be obtained by using an epoxy compound in combination. Is obtained. In addition, Patent Document 8 describes that V-0 can be obtained by using a fiber in combination with a hydroxide.

However, in the example described in Patent Document 6, since V-0 cannot be obtained unless 30 parts of talc is blended, the surface appearance is likely to be impaired, and heat resistance is not considered. On the other hand, in the examples described in Patent Document 7 or Patent Document 8, V-0 cannot be obtained unless the flame retardant is added in excess of 20 parts, and there is a concern that the physical properties inherent to polylactic acid may be greatly impaired. .
Japanese Patent Laying-Open No. 2005-023260 JP-A-2005-139441 JP 2005-162873 A JP 2005-336365 A JP 2005-340442 A JP 2005-350537 A JP 2006-016446 A JP 2006-096443 A

  The present invention is intended to solve the above-described problems, and an object thereof is to provide a flame retardant polylactic acid resin composition having excellent heat resistance.

As a result of intensive studies to solve the above problems, the present inventor blends a specific phosphorus compound, a (meth) acrylic acid ester compound, and a peroxide with a polylactic acid resin, or a specific phosphorus. The inventors have found that the above problem can be solved by blending a compound, an organic crystal nucleating agent, and a plasticizer, and have reached the present invention.
That is, the gist of the present invention is as follows.
(1) 3 to 30% by mass of a pentavalent phosphorus compound having a polylactic acid resin as a main component and the proportion of the total carbon atoms contained in the aromatic ring in the molecular weight is 60% or more, (meth) acrylic acid ester compound A flame retardant polylactic acid resin composition obtained by melt-kneading a mixture containing 0.01 to 5% by mass of a compound and 0.001% by mass or more of a peroxide.
(2) 3 to 30% by mass of a pentavalent phosphorus compound having a polylactic acid resin as a main component and the proportion of the total carbon atoms contained in the aromatic ring in the molecular weight is 60% or more; A flame-retardant polylactic acid resin composition comprising 1 to 5% by mass of a plasticizer comprising 1 to 5% by mass, an aliphatic ester derivative and / or an aliphatic polyether derivative.
(3) The flame retardant polylactic acid resin composition according to (1), which contains 0.1 to 5% by mass of an organic crystal nucleating agent.
(4) The organic crystal nucleating agent is N, N ′, N ″ -tricyclohexyltrimesic acid amide and / or N, N′-ethylenebis (12-hydroxystearic acid) amide and / or octane The flame-retardant polylactic acid resin composition according to (2) or (3), which is dicarboxylic acid dibenzoylhydrazide.
(5) The flame retardant polylactic acid resin according to any one of (1) to (4), comprising 0.05 to 8% by mass of a hydrolysis inhibitor comprising a carbodiimide compound and / or an epoxy compound. Composition.
(6) A molded article obtained by molding the polylactic acid resin composition according to any one of (1) to (5) above.

  ADVANTAGE OF THE INVENTION According to this invention, the resin composition excellent in the flame retardance and heat resistance can be provided. By using this resin composition for molded articles such as casings of electrical products, the range of use of polylactic acid resin, which is a low environmental load material, can be greatly expanded, and the industrial utility value is extremely high.

The present invention will be described in detail below.
The resin composition of the present invention is obtained by melt-kneading a mixture containing a polylactic acid resin as a main component and containing a phosphorus compound, a (meth) acrylic acid ester compound, and a peroxide, or a polylactic acid resin as a main component. A resin composition containing, as components, a phosphorus compound, an organic crystal nucleating agent, and a plasticizer.

  As the polylactic acid resin, poly (L-lactic acid), poly (D-lactic acid), and a mixture or copolymer thereof can be used from the viewpoint of heat resistance and moldability. However, biodegradability and molding processability can be used. From this point of view, it is preferable that poly (L-lactic acid) is mainly used.

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

  The melt flow rate (for example, a value according to JIS standard K-7210 (test condition 4)) at 190 ° C. and a load of 21.2 N of the polylactic acid resin is usually 0.1 to 50 g / 10 minutes, preferably 0.2 to 20 g / 10 minutes, optimally 0.5 to 10 g / 10 minutes. 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 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 biodegradable resin 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, an acid anhydride And a method of increasing the molecular weight of the resin by using an object. 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 present invention, the phosphorus compound is blended for the purpose of obtaining flame retardancy by the phosphoric acid layer and the carbonized layer generated during combustion, and the proportion of the total carbon atom contained in the aromatic ring in the molecular weight is 60%. It is necessary to be a pentavalent phosphorus compound that is at least%. Specific compounds include phosphine oxide compounds such as triphenyl phosphine oxide (ratio of total carbon atoms contained in aromatic rings in the molecular weight: 78%), triphenyl phosphate (same ratio: 66%), and the like. And oxo acid derivatives thereof.
With a phosphorus compound in which the proportion of the total carbon atoms contained in the aromatic ring is less than 60% in the molecular weight, the intended flame retardancy cannot be obtained. In addition, phosphorus compounds other than pentavalent have a safety problem in terms of toxicity. In addition, in the phosphorus compound applicable to alcohol, phenols, or any of free acids, the operability at the time of shaping | molding falls by durability of polylactic acid resin, and durability may fall.

  Content of the phosphorus compound in a mixture or a resin composition is 3-30 mass%, Preferably it is 10-20 mass%. If the content is less than 3% by mass, the intended flame retardancy cannot be obtained, and if it exceeds 30% by mass, the moldability is lowered.

In the present invention, the (meth) acrylic acid ester compound is blended for the purpose of accelerating crystallization of the resin composition and improving heat resistance, has high reactivity with the polylactic acid resin, and is a monomer. Is less likely to remain, less toxic, and less colored resin, so that it has two or more (meth) acryl groups in the molecule, or one or more (meth) acryl groups and one or more A compound having a glycidyl group or a vinyl group is preferred.
Specific 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 alkylenes with various lengths of these alkylene glycols And the like, butanediol methacrylate, butanediol acrylate, and the like.

  Content of the (meth) acrylic acid ester compound in a mixture is 0.01-5 mass%, Preferably it is 0.05-1 mass%. If the content is less than 0.01% by mass, the desired heat resistance cannot be obtained, and if it exceeds 5% by mass, the operability during kneading is lowered.

In the present invention, the peroxide is blended for the purpose of promoting the reaction between the (meth) acrylic acid ester compound and polylactic acid and improving the heat resistance.
Specific compounds 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 content of peroxide in the mixture is 0.001% by mass or more, preferably 0.001 to 10% by mass. If the content is less than 0.001% by mass, the intended heat resistance cannot be obtained, and if it exceeds 10% by mass, the operability during kneading may be reduced.

The resin composition of the present invention can be produced by melt-kneading a mixture comprising a polylactic acid resin, a phosphorus compound, a (meth) acrylic acid ester compound, and a peroxide. By melt-kneading the mixture, the reaction between the polylactic acid resin and the (meth) acrylic ester compound is promoted, so that a resin composition with accelerated crystallization and improved heat resistance can be obtained.
The melt kneading can be performed using a single screw or twin screw 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 + 5 ° C.) to (melting point of polylactic acid resin + 100 ° C.), and the kneading time is preferably in the range of 20 seconds to 30 minutes. When the temperature is lower than this range or for a short time, kneading or reaction becomes insufficient. On the other hand, when the temperature is high or for a long time, the resin may be decomposed or colored.

  In the resin composition obtained by melt-kneading a mixture of the polylactic acid resin, the phosphorus compound, the (meth) acrylic ester compound, and the peroxide, an organic crystal nucleating agent to be described later is added in an amount of 0.0. You may make it contain 1-5 mass%. By including 0.1% by mass or more of the organic crystal nucleating agent, the releasability at the time of molding can be improved, but when it exceeds 5% by mass, the load at the time of melt kneading becomes unstable. This is not preferable.

  The flame retardant polylactic acid resin composition of the present invention may be a resin composition in which the above-described polylactic acid resin and a phosphorus compound contain an organic crystal nucleating agent and a plasticizer.

In the present invention, the organic crystal nucleating agent is blended for the purpose of promoting crystallization of the resin composition and improving heat resistance, and is represented by the general formulas (1) to (3). More than one kind of organic crystal nucleating agent may be mentioned.
R ^1- (CONH-R ² ) _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. R ² represents an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 2 to 18 carbon atoms, a cycloalkyl group or cycloalkenyl group having 3 to 12 carbon atoms, a phenyl group, a naphthyl group, an anthryl group, or a formula (a) The group represented by any one of (d) is represented. a represents an integer of 2 to 6. ]
[Wherein R ³ represents 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 an atom. l represents an integer of 1 to 5. ]
[Wherein, R ⁴ represents a linear or branched alkylene group having 1 to ⁴ carbon atoms. R ⁵ has the same meaning as R ³ described above. m represents an integer of 0 to 5. ]
[Wherein, R ⁶ has the same meaning as R ³ described above. n represents an integer of 1 to 5. ]
[Wherein, R ⁷ has the same meaning as R ⁴ described above, and R ⁸ has the same meaning as R ³ described above. o represents an integer of 0-6. ]
^{R 9 - (NHCO-R 10} ) 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. R ¹⁰ has the same meaning as R ² described above. f represents an integer of 2-6. ]
^{R 11 - (CONHNHCO-R 12} ) h (3)
[Wherein R ¹¹ represents a saturated or unsaturated fatty chain having 2 to 30 carbon atoms, an unsaturated alicyclic ring, or an aromatic ring. R ¹² has the same meaning as R ² described above. h represents an integer of 2 to 6. ]

  Specific examples of the organic crystal nucleating agent include hexamethylene bis-9, 10-dihydroxystearic acid bisamide, p-xylylene bis-9, 10 dihydroxystearic acid amide, decanedicarboxylic acid dibenzoyl hydrazide, hexanedicarboxylic 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-cyclohexane Dicarboxylic acid dianilide, 2,6-naphthalenedicarboxylic acid dicyclohexylamide, N, N′-dibenzoyl-1,4-diaminocyclohexane, N, N′-dicyclohexanecarbonyl-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 content of the organic crystal nucleating agent in the resin composition is 0.1 to 5% by mass, preferably 0.5 to 3% by mass. If the content is less than 0.1% by mass, the desired heat resistance cannot be obtained, and if it exceeds 5% by mass, the operability during kneading is lowered.

  In the present invention, the plasticizer is blended for the purpose of promoting the dispersion of the organic crystal nucleating agent in the polylactic acid resin, and is one or more selected from aliphatic ester derivatives or aliphatic polyether derivatives. It is a plasticizer. Specific examples of the compound include glycerin diacetomonocaprate and glycerin diacetomonolaurate.

  Content of the plasticizer in a resin composition is 1-10 mass%. If the content is less than 1% by mass, the intended effect cannot be obtained, and if it exceeds 10% by mass, the operability during kneading is lowered.

The resin composition of the present invention may contain one or more hydrolysis inhibitors selected from carbodiimide compounds and epoxy compounds. By including a hydrolysis inhibitor, it is possible to improve the durability of the resin composition and stably maintain the flame retardancy and heat resistance for a long period of time. Various compounds can be used as the specific compound, and it is particularly preferable to use a carbodiimide compound containing an isocyanate group.
The carbodiimide compound containing an isocyanate group is not particularly limited as long as it has a structure in which an isocyanate group is introduced into a compound having one or more carbodiimide groups in the molecule. The carbodiimide skeleton includes N, N′-di -O-triylcarbodiimide, N, N'-dioctyldecylcarbodiimide, N, N'-di-2,6-dimethylphenylcarbodiimide, N-triyl-N'-cyclohexylcarbodiimide, N-triyl-N'-phenylcarbodiimide N, N′-di-p-nitrophenylcarbodiimide, N, N′-di-p-hydroxyphenylcarbodiimide, N, N′-di-cyclohexylcarbodiimide, N, N′-di-p-triylcarbodiimide, p-phenylene-bis-di-o-triylcarbodiimide, 4,4 ' -Dicyclohexylmethane carbodiimide, tetramethylxylylene carbodiimide, N, N-dimethylphenyl carbodiimide, N, N'-di-2,6-diisopropylphenyl carbodiimide and the like are exemplified.

  Content of the hydrolysis inhibitor in a resin composition is 0.05-8 mass%, Preferably, it is 0.1-5 mass%. If the content is less than 0.05% by mass, the intended durability may not be obtained, and if it exceeds 8% by mass, the color tone may be greatly impaired.

In the resin composition of the present invention, pigments, heat stabilizers, antioxidants, inorganic fillers, plant fibers, weathering agents, plasticizers, lubricants, mold release agents, antistatic agents, as long as the properties are not significantly impaired. Etc. can be added.
Examples of heat stabilizers and antioxidants include hindered phenols, hindered amines, sulfur compounds, copper compounds, alkali metal halides, and the like. Examples of the inorganic filler include talc, calcium carbonate, zinc carbonate, wollastonite, silica, alumina, magnesia, calcium silicate, sodium aluminate, calcium aluminate, sodium aluminosilicate, magnesium silicate, glass balloon, carbon black Zinc oxide, antimony trioxide, zeolite, hydrotalcite, metal fiber, metal whisker, ceramic whisker, potassium titanate, boron nitride, graphite, carbon fiber and the like are exemplified. Examples of plant fibers include kenaf fibers. In addition, the method of mixing these with the resin composition of this invention is not specifically limited.

  The resin composition of the present invention can be 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. In particular, it is preferable to adopt an injection molding method, and in addition to a general injection molding method, gas injection molding, injection press molding, or 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-20 ° C.) of the resin composition. If the molding temperature is too low, the operability becomes unstable, such as short-circuiting in the molded body, and it tends to be overloaded. Conversely, if the molding temperature is too high, the resin composition will decompose and the resulting molded body 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, for example, there is a method of promoting crystallization in a mold at the time of injection molding. In that case, the glass composition has a glass transition temperature of + 20 ° C. or higher and a melting point of −20 ° C. or lower. A method in which the molded body is held for a certain period of time in a mold held in a mold and then taken out from the mold is preferable. Moreover, even if it is the molded object taken out from the metal mold | die without taking such a method, crystallization is accelerated | stimulated again by heat-processing above the glass transition temperature and below (melting | fusing point-20 degreeC). it can.

  Specific examples of the molded body using the resin composition of the present invention include personal computer casing parts and casings, mobile phone casing parts and casings, other resin parts for electrical appliances such as OA equipment casing parts, bumpers, Examples include resin panels for automobiles such as instrument panels, console boxes, garnishes, door trims, ceilings, floors, and panels around the engine. Moreover, it can also be set as a film, a sheet | seat, a hollow molded product, etc.

Hereinafter, the present invention will be described more specifically with reference to examples. The measuring method used for evaluation of the resin composition of an Example and a comparative example is as follows.
(1) Thermal deformation temperature:
Based on ISO 75, the heat distortion temperature was measured with a load of 0.45 MPa. The heat distortion temperature is preferably 80 ° C. or higher.
(2) Flame retardancy:
Measured according to UL94. A test piece having a thickness of 1.5 mm was used. The flame retardancy is preferably V-0.
(3) Bending strength:
Measurement was performed in accordance with ISO178. The bending strength is preferably 60 MPa or more.

Moreover, the various raw materials used for the Example and the comparative example are as follows.
(1) Polylactic acid resin:
“6201D” manufactured by Cargill Dow (melting point: 170 ° C., D-lactic acid component ratio: 1.3 mol%, melt flow rate: 20 g / 10 min)
(2) (Meth) acrylic acid ester compound:
Ethylene glycol dimethacrylate ("Blemmer PDE-50" manufactured by NOF Corporation)
(3) Phosphorus compound:
・ Triphenylphosphine oxide (ratio of total carbon atom content in aromatic ring in molecular weight: 78%, “TPPO” manufactured by Hokuko Chemical)
・ Triphenyl phosphate (same ratio: 66%, “TPP” manufactured by Daihachi Chemical)
Resorcinol bis (di-2,6-xylenyl) phosphate (same ratio: 52%, “PX200” manufactured by the same company)
(4) Hydrolysis inhibitor:
Isocyanate-modified carbodiimide (Isocyanate group content 1 to 3%, "LA-1" manufactured by Nisshinbo)
(5) Peroxide:
Di-t-butyl peroxide (Nippon Yushi "Perbutyl D")
(6) Organic crystal nucleating agent:
N, N′-ethylenebis (12-hydroxystearic acid) amide (“T-530SF” manufactured by Ito Oil Co., Ltd., hereinafter referred to as “530SF”)
・ N, N ′, N ″ -Tricyclohexyltrimesic acid amide (“TF-1” manufactured by Shin Nippon Chemical Co., Ltd.)
Octanedicarboxylic acid dibenzoyl hydrazide (“T-1287N” manufactured by Adeka, hereinafter referred to as “1287N”)
(7) Plasticizer:
Glycerin diacetomonocaprate ("PL-019" manufactured by Riken Vitamin)

Example 1
Using a twin screw extruder (TEM37BS type manufactured by Toshiba Machine Co., Ltd.), 83 parts by mass of polylactic acid resin, 14 parts by mass of “TPPO” as a phosphorus compound, 0.8 parts by mass of “TF-1” as an organic crystal nucleating agent, hydrolysis 1.5 parts by mass of the inhibitor was dry blended and supplied from the root supply port of the extruder, and extrusion was carried out while venting was performed under the conditions of a barrel temperature of 180 ° C., a screw rotation speed of 280 rpm, and a discharge of 15 kg / h. Further, 0.10 parts by mass of (meth) acrylic acid ester compound and 0.2 parts by mass of peroxide were supplied into the cylinder. The resin discharged from the tip of the extruder was cut into pellets to obtain pellets of the resin composition.
The obtained pellets were vacuum-dried at 70 ° C. for 24 hours, and then a test piece for measuring general physical properties (ASTM) while adjusting the mold surface temperature to 105 ° C. using an IS-80G injection molding machine manufactured by Toshiba Machine Co., Ltd. Mold) and prepared for various measurements. A part of the test piece was exposed to a high temperature and high humidity environment of 60 ° C. and 95% RH for 20 days, and the bending strength was measured.

Examples 2-9 and Comparative Examples 1-6
Resin composition pellets were obtained in the same manner as in Example 1 except that the amount and type of polylactic acid resin, phosphorus compound, (meth) acrylic acid ester compound, peroxide, organic crystal nucleating agent, and hydrolysis inhibitor were changed. This was injection molded to measure various physical properties.

  Table 1 summarizes the evaluation results of Examples 1 to 9 and Comparative Examples 1 to 6.

  As is clear from Table 1, in Examples 1 to 9, it was found that resin compositions having excellent flame retardancy and heat resistance were obtained. In Comparative Example 1, since the amount of the phosphorus compound was small, the result was inferior in flame retardancy. In Comparative Example 2, molding was difficult due to the large amount of phosphorus compound. Moreover, in the comparative example 3, since there were few compounding quantities of the (meth) acrylic acid ester compound, it became a result inferior to heat resistance. In Comparative Example 4, kneading was difficult because the amount of the (meth) acrylic acid ester compound was large. In Comparative Example 5, molding was difficult because the amount of peroxide was small. In Comparative Example 6, since the phosphorus compound in which the proportion of the total carbon atoms contained in the aromatic ring in the molecular weight was less than 60% was used as the phosphorus compound, the result was inferior in flame retardancy.

  Moreover, in Examples 1-3, 6-9, since the compounding quantity of the hydrolysis inhibitor was suitable, compared with Examples 4 and 5, it is more suitable in terms of durability or color tone. Results were obtained. Further, in Examples 1 to 5, 8, and 9, since the blending amount of the organic crystal nucleating agent was appropriate, compared with Examples 6 and 7, in terms of moldability or operability during kneading, Good results have been obtained.

Example 10
Using a twin screw extruder (TEM 37BS type manufactured by Toshiba Machine Co., Ltd.), 79 parts by mass of polylactic acid resin, 1.5 parts by mass of hydrolysis inhibitor, 1.5 parts by mass of “530SF” as an organic crystal nucleating agent, and “ TPPO ”14 parts by mass was dry blended and supplied from the root supply port of the extruder, and extrusion was carried out while venting was effected under the conditions of a barrel temperature of 180 ° C., a screw rotation speed of 280 rpm, and a discharge of 15 kg / h. Further, 4 parts by mass of a plasticizer was supplied into the cylinder. The resin discharged from the tip of the extruder was cut into pellets to obtain pellets of the resin composition. The obtained pellets were vacuum-dried at 70 ° C. for 24 hours, and then a test piece for measuring general physical properties (ASTM) while adjusting the mold surface temperature to 105 ° C. using an IS-80G injection molding machine manufactured by Toshiba Machine Co., Ltd. Mold) and prepared for various measurements. A part of the test piece was exposed to a high temperature and high humidity environment of 60 ° C. and 95% RH for 20 days, and the bending strength was measured.

Examples 11-16 and Comparative Examples 7-13
Resin composition pellets were obtained in the same manner as in Example 10 except that the amount and type of polylactic acid resin, phosphorus compound, organic crystal nucleating agent, plasticizer, and hydrolysis inhibitor were changed. Physical properties were measured.

  Table 2 summarizes the evaluation results of Examples 10 to 16 and Comparative Examples 7 to 13.

  As is apparent from Table 2, in Examples 10 to 16, it was found that a resin composition excellent in flame retardancy and heat resistance was obtained. In Comparative Example 7, since the amount of the phosphorus compound was small, the result was inferior in flame retardancy. In Comparative Example 8, molding was difficult because the amount of the phosphorus compound was large. In Comparative Example 9, since the amount of the organic crystal nucleating agent was small, the heat resistance was poor. In Comparative Example 10, kneading was difficult because the amount of the organic crystal nucleating agent was large. In Comparative Example 11, since the blending amount of the plasticizer was small, the heat resistance was inferior. In Comparative Example 12, kneading was difficult because of the large amount of plasticizer. In Comparative Example 13, since the phosphorus compound in which the proportion of the total carbon atoms contained in the aromatic ring in the molecular weight was less than 60% was used as the phosphorus compound, the result was inferior in flame retardancy.

  Moreover, in Examples 10-12, 15, and 16, since the compounding quantity of the hydrolysis inhibitor was suitable, compared with Examples 13 and 14, it is more suitable at the point of durability or a color tone. Results were obtained.

Claims (6)

3-30% by mass of a pentavalent phosphorus compound having a polylactic acid resin as a main component and the proportion of the total carbon atoms contained in the aromatic ring in the molecular weight is 60% or more, and a (meth) acrylic acid ester compound of 0. A flame-retardant polylactic acid resin composition obtained by melt-kneading a mixture containing 01 to 5 mass% and a peroxide of 0.001 mass% or more. 3 to 30% by mass of a pentavalent phosphorus compound having a polylactic acid resin as a main component and the proportion of total carbon atoms contained in the aromatic ring in the molecular weight is 60% or more, and 0.1 to 5 of the organic crystal nucleating agent. A flame-retardant polylactic acid resin composition comprising 1% by mass to 10% by mass of a plasticizer composed of mass%, an aliphatic ester derivative and / or an aliphatic polyether derivative. The flame retardant polylactic acid resin composition according to claim 1, which contains 0.1 to 5% by mass of an organic crystal nucleating agent. The organic crystal nucleating agent is N, N ′, N ″ -tricyclohexyltrimesic acid amide and / or N, N′-ethylenebis (12-hydroxystearic acid) amide and / or octanedicarboxylic acid diester. The flame retardant polylactic acid resin composition according to claim 2, which is benzoyl hydrazide. The flame retardant polylactic acid resin composition according to any one of claims 1 to 4, comprising 0.05 to 8% by mass of a hydrolysis inhibitor composed of a carbodiimide compound and / or an epoxy compound. The molded object formed by shape | molding the polylactic acid resin composition in any one of Claims 1-5.