JP4637466B2 - Resin composition and molded body comprising the same - Google Patents

Description

  The present invention relates to a resin composition excellent in color tone, comprising a biodegradable resin and a vegetable fiber material subjected to delignification treatment.

  In general, resins such as polypropylene (PP), ABS, 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. However, when they are 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. Furthermore, polylactic acid can be produced using plants such as corn and sweet potato as raw materials.

  On the other hand, Patent Document 1 discloses a fiber-based reinforcing material using natural fibers such as hemp, jute, kenaf, and Manila hemp as an attempt to reduce the environmental load using plant fiber as a filler. Yes.

  In addition, it is described in Patent Documents 2 and 3 that bleaching is performed by delignifying kenaf or rice husk fibers.

JP 2002-363862 A JP-A-6-144912 JP 2001-288686 A

  The material described in Patent Document 1 cannot always be said to be excellent in color tone, and it has been necessary to improve this point in order to use it as an industrial product. In addition, bleaching natural fibers by delignification treatment has been performed for a long time, but there was no example in which this treatment was applied to a biodegradable resin filler.

  The present invention is intended to solve the above-described problems, and achieves both color tone and mechanical properties in a resin composition mainly composed of a biodegradable resin and a vegetable fiber material.

As a result of intensive studies in order to solve the above problems, the present inventors have found that a resin composition in which polylactic acid and kenaf subjected to delignification treatment are mixed in a specific range satisfies color tone and mechanical properties. As a result, the present invention has been reached.

That is, the gist of the present invention is as follows.
(1) It is composed of 50 to 95% by mass of polylactic acid and 50 to 5% by mass of kenaf subjected to delignification treatment, and the L value of the pellet represented by Hunter Lab color system is 30 or more. Resin composition.
(2) A molded product obtained by molding the resin composition according to (1).

According to the present invention, a resin composition having both a color tone mainly composed of polylactic acid and kenaf and mechanical properties can be obtained, and can be suitably used as various molded articles. By improving the color tone of the resin composition, when it is used as a molded product, the colorability to adjust to various colors is improved, and molded products having various color tones can be produced. Further, since the reinforcement efficiency of the kenaf as a reinforcing material is improved, a molded product having the same mechanical properties can be obtained with a smaller amount of the reinforcing material.

  Hereinafter, the present invention will be described in detail.

The resin composition of the present invention comprises polylactic acid (A) 50 to 95% by mass and delignified kenaf (B) 50 to 5% by mass. A preferable mixing range is (A) / (B) = 65. It is -95 mass% / 35-5 mass%, More preferably, it is (A) / (B) = 80-95 mass% / 20-5 mass%. When the blending amount of (B) exceeds 50% by mass, melt-kneading becomes difficult and the operability is inferior. As a result, the color tone is deteriorated due to heat. Tend to be difficult to apply. In addition, when the blending amount of polylactic acid exceeds 95% by mass and the blending amount of delignified kenaf is less than 5% by mass, the reinforcing effect on the physical properties of the plant reinforcing material is hardly exhibited. .

The polylactic acid, poly (L- lactic acid), poly (D-lactic acid) is a etc. Poly milk acid typical example of such.

Heat resistance, poly terms of moldability (L- lactic acid), poly (D-lactic acid), and may be a mixture or copolymers of these, from the viewpoint of biodegradability, poly (L- lactic acid ) Is preferred.

  Further, the melting point of polylactic acid mainly composed of poly (L-lactic acid) varies depending on the optical purity. However, in the present invention, the melting point is 160 ° C. or higher in consideration of the mechanical properties and heat resistance of the molded product. It is preferable that 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 (for example, a value according to JIS standard K-7210 (test condition 4)) of polylactic acid at 190 ° C. and a load of 21.2 N is 0.1 to 50 g / 10 minutes, preferably 0.2 to 20 g / 10 minutes. More preferably, it is 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 are poor. When the melt flow rate is less than 0.1 g / 10 min, the load during the molding process becomes too high and the operability may be lowered.

Polylactic acid is usually 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 polylactic acid to a predetermined range, when the melt flow rate is too large, a small amount of chain extender, for example, diisocyanate compound, bisoxazoline compound, epoxy compound, acid anhydride, etc. And a method of increasing the molecular weight of the resin. 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.

Polylactic acid may be copolymerized with monomers other than the main constituent components within a range not impairing biodegradability and mechanical properties. For example, as the acid component, terephthalic acid, isophthalic acid, orthophthalic acid, 2,6-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, methylterephthalephthalate Acid, 4,4'-biphenyl dicarboxylic acid, 2,2'-biphenyl dicarboxylic acid, 4,4'-biphenyl ether dicarboxylic acid, 4,4'-diphenylmethane dicarboxylic acid, 4,4'-diphenylsulfone dicarboxylic acid, 4 Aromatic dicarboxylic acids such as 4,4'-diphenylisopropylidenedicarboxylic acid, adipic acid, sebacic acid, oxalic acid, malonic acid, succinic acid, azelaic acid, undecanedioic acid, dodecanedioic acid, aicosanedioic acid, hydrogenated dimer acid Saturated aliphatic dicarboxylic acid, fumaric acid, maleic acid, itako Unsaturated aliphatic dicarboxylic acids such as acid, mesaconic acid, citraconic acid and dimer acid and their anhydrides, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 2, Examples thereof include alicyclic dicarboxylic acids such as 5-norbornene dicarboxylic acid and tetrahydrophthalic acid. As diol components, 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 their An aromatic diol such as an ethylene oxide adduct, hydroquinone, or resorcinol may be copolymerized. Furthermore, hydroxycarboxylic acids such as p-hydroxybenzoic acid, p- (2-hydroxyethoxy) benzoic acid, and 6-hydroxycaproic acid, and lactone compounds such as δ-valerolactone, γ-butyrolactone, and ε-caprolactone are commonly used. It may be polymerized. Moreover, an organic phosphorus compound may be copolymerized in order to impart flame retardancy.

If the amount is small, the polylactic acid component includes other polyester resins such as polyethylene terephthalate, polycarbonate, polyarylate, polycyclohexylenedimethylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate / terephthalate, polybutylene. Consists of isophthalate / terephthalate, polypolyethylene terephthalate / cyclohexylene dimethylene terephthalate, cyclohexylene dimethylene isophthalate / terephthalate, poly (p-hydroxybenzoic acid / ethylene terephthalate), 1,3-propanediol, a plant-derived raw material Polytetramethylene terephthalate or the like may be mixed.

In the present invention, using kenaf subjected to delignification in conjunction with polylactic acid. Ke Naf in West Africa native Malvaceae cotton rose group first-year plants, has been attracting attention from the point of view of forest protection as a non-wood pulp raw materials as an alternative to wood pulp.

  In general, plant fiber materials contain a large amount of lignin in addition to cellulose and hemicellulose as main components. For example, softwood contains 20-35% by weight, hardwood contains 17-28% by weight, and kenaf contains about 18% by weight. By removing these and improving the purity of the fiber, the color tone when such a vegetable fiber material is added to the biodegradable resin can be greatly improved, and the reinforcement efficiency as a reinforcing material of the resin material can be improved. It can be remarkably improved.

  As for the color tone of the resin composition of this invention, it is preferable that L value at the time of expressing with the Hunter color system mentioned later about a pellet is 30 or more, and 35 or more is more preferable. When the L value is less than this value, variations in colors that can be toned become narrow, and it is necessary to increase the amount of colorant required for toning, resulting in a decrease in physical properties.

  As the delignification treatment, a known method may be appropriately used. (1) A method using a strong alkali solution such as a sodium hydroxide solution or a potassium hydroxide solution, and (2) heating using sodium hydroxide and sodium sulfide. And (3) a method of treating with molybdate and hydrogen peroxide under acidic conditions. In addition, the color development of lignin can be suppressed by further bleaching in addition to the delignification treatment.

A means for mixing polylactic acid and kenaf subjected to delignification treatment is not particularly limited, and examples thereof include a melt kneading method using a general 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 + 5 ° C.) to (melting point of polylactic acid + 100 ° C.), and the kneading time is preferably 20 seconds to 30 minutes. If the temperature is lower or shorter than this range, kneading or reaction becomes insufficient, and if the temperature is higher or longer, the resin may be decomposed or colored. In blending, dry blending or a method of supplying kenaf using a powder feeder is preferable.

The polylactic acid preferably has a melting point of about 200 ° C. or lower if it exhibits crystallinity, and preferably has a flow start temperature of about 170 ° C. or lower by a flow tester if it is an amorphous resin ( The flow start temperature is a relatively general index indicating the thermal properties of the resin, and can be measured, for example, by a device such as CFT-500C manufactured by Shimadzu Corporation). If kenaf is kneaded with a melting point exceeding 200 ° C. or a flow starting temperature exceeding 170 ° C., coloring due to heat becomes prominent, and the target color tone improving effect of the present invention may be reduced.

The resin composition of the present invention may further contain a (meth) acrylic acid ester compound in addition to the above-mentioned polylactic acid and kenaf subjected to delignification treatment . By this component, the resin component is cross-linked, and mechanical strength and heat resistance are improved, and dimensional stability is also improved. The (meth) acrylic acid ester compound has high reactivity with the biodegradable resin, it is difficult for the monomer to remain, its toxicity is relatively low, and the resin is less colored, so there are two or more (meth) acrylic compounds in the molecule. Compounds having a group or having one or more (meth) acryl groups and one or more glycidyl groups or vinyl groups are 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, and these alkylene glycols may be copolymers of alkylenes of various lengths, but also butanediol methacrylate, butanediol acrylate, etc. Can be mentioned.

As for the compounding quantity of a (meth) acrylic acid ester compound, 0.01-20 mass parts is preferable with respect to 100 mass parts of polylactic acid , More preferably, it is 0.05-10 mass parts, More preferably, it is 0.1-5. Part by mass.

In blending the (meth) acrylic acid ester compound, it is preferable to use a peroxide in combination because the crosslinking reaction is promoted. Specific examples of peroxides include benzoyl peroxide, bis (butylperoxy) trimethylcyclohexane, bis (butylperoxy) cyclododecane, butylbis (butylperoxy) valerate, dicumyl peroxide, butylperoxybenzoate, dibutyl Examples thereof include peroxide, bis (butylperoxy) diisopropylbenzene, dimethyldi (butylperoxy) hexane, dimethyldi (butylperoxy) hexyne, and butylperoxycumene. 0.1-20 mass parts is preferable with respect to 100 mass parts of polylactic acids , and, as for the compounding quantity of a peroxide, More preferably, it is 0.1-10 mass parts. Although it can be used even if it exceeds 20 parts by mass, it is disadvantageous in terms of cost. In addition, since such a peroxide 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.

  As a preferable method when the (meth) acrylate compound and the peroxide are used in combination, a method in which the (meth) acrylate compound and / or the peroxide is dissolved or dispersed in a medium and injected into a kneader. As a result, the operability can be remarkably improved. That is, during the melt kneading of the mixed polyester resin component and the peroxide, a solution or dispersion of the (meth) acrylic acid ester compound is injected, or during the melt kneading of the polyester resin, the (meth) acrylic acid ester A solution or dispersion of a compound and a peroxide can be injected and melt kneaded.

As a medium for dissolving or dispersing the (meth) acrylic ester compound and / or peroxide, a general one is used, and is not particularly limited, but a plasticizer excellent in compatibility with the polylactic acid to be used is preferable. For example, one or more selected from aliphatic polycarboxylic acid ester derivatives, aliphatic polyhydric alcohol ester derivatives, aliphatic oxyester derivatives, aliphatic polyether derivatives, aliphatic polyether polycarboxylic acid ester derivatives, etc. Examples include plasticizers. Specific examples of the compound include dimethyl adipate, dibutyl adipate, triethylene glycol diacetate, methyl acetyl ricinoleate, acetyl tributyl citric acid, polyethylene glycol, and dibutyl diglycol succinate. As a usage-amount of a plasticizer, 30 mass parts or less are preferable with respect to 100 mass parts of polylactic acid , and 0.1-20 mass parts is still more preferable. When the reactivity of the crosslinking agent is low, it is not necessary to use the plasticizer, but when the reactivity is high, it is preferable to use 0.1 parts by mass or more. In addition, since this medium may volatilize at the time of mixing with resin, even if it uses it at the time of manufacture, this medium may not be contained in the obtained resin composition.

The resin composition of the present invention may contain a layered silicate for the purpose of improving mechanical strength and heat resistance. The blending amount is preferably 0.1 to 20 parts by mass, more preferably 0.2 to 10 parts by mass with respect to 100 parts by mass of polylactic acid . Specific examples of the layered silicate include smectite, vermiculite, and swellable fluorine mica. Examples of smectites include montmorillonite, beidellite, hectorite, and saponite. Examples of swellable fluorine mica include Na-type fluorine tetrasilicon mica, Na-type teniolite, Li-type teniolite, etc. In addition to the above, aluminum and magnesium such as kanemite, macatite, magadiite, and kenyaite are not included. Layered silicates can also be used. These layered silicates may be natural products or synthetic products. The synthetic product may be produced by any method such as a melting method, an intercalation method, or a hydrothermal method. These layered silicates may be used alone or in combination of two or more types having different mineral types, production areas, production methods, particle sizes and the like.

  The layered silicate is preferably pretreated with an organic cation. Examples of the organic cation include ammonium ions generated by protonation of primary to tertiary amines, onium ions such as quaternary ammonium ions and phosphonium ions. Examples of the primary amine include octylamine, dodecylamine, octadecylamine and the like. Examples of secondary amines include dioctylamine, methyloctadecylamine, and dioctadecylamine. Examples of the tertiary amine include trioctylamine, dimethyldodecylamine, didodecylmonomethylamine and the like. Examples of quaternary ammonium ions include tetraethylammonium, octadecyltrimethylammonium, dimethyldioctadecylammonium, dihydroxyethylmethyloctadecylammonium, methyldodecylbis (polyethylene glycol) ammonium, methyldiethyl (polypropyleneglycol) ammonium and the like. Furthermore, examples of the phosphonium ion include tetraethylphosphonium, tetrabutylphosphonium, hexadecyltributylphosphonium, tetrakis (hydroxymethyl) phosphonium, 2-hydroxyethyltriphenylphosphonium, and the like. Of these, treatment with ammonium ions having one or more hydroxyl groups in the molecule, such as dihydroxyethyl methyl octadecyl ammonium, methyl dodecyl bis (polyethylene glycol) ammonium, methyl diethyl (polypropylene glycol) ammonium, 2-hydroxyethyl triphenylphosphonium, etc. The layered silicate is particularly preferable because it has a high affinity with a polyester resin, particularly a biodegradable polyester resin, and the dispersibility of the layered silicate is improved. These cations may be used alone or in combination of two or more.

  In addition, as a method of treating the layered silicate with the organic cation, first, the layered silicate is dispersed in water or alcohol, and the organic cation is added in the form of a salt to the layered silicate, thereby stirring the layered silicate. Examples of the method include ion-exchange of salt inorganic ions with organic onium ions, followed by filtration, washing, and drying.

When layered silicate is used, a compatibilizing agent may be used in order to improve dispersibility in polylactic acid . The addition amount is preferably 0.01 to 10 parts by mass, more preferably 0.02 to 5 parts by mass with respect to 100 parts by mass of polylactic acid . If it exceeds 10 parts by mass, the heat resistance and mechanical strength of the resin composition may decrease. As the compatibilizing agent, compounds such as polyalkylene oxide, aliphatic polyester, polyhydric alcohol ester, polyhydric carboxylic acid ester having affinity with both polyester resin, especially biodegradable polyester resin and layered silicate are used. It is done. Examples of polyalkylene oxides include polyethylene glycol, polypropylene glycol, polybutylene glycol, and copolymers thereof, one or two of the terminal hydroxyl groups may be alkoxy-capped, and may be monocarboxylic acid or dicarboxylic acid. It may be esterified with an acid. Examples of aliphatic polyesters include polylactic acid, polyglycolic acid, poly (3-hydroxybutyric acid), poly (3-hydroxyvaleric acid), poly (3-hydroxycaproic acid) and other polyhydroxycarboxylic acids, poly (ε -Caprolactone), poly (ω-hydroxyalkanoate) represented by poly (δ-valerolactone), poly (ethylene succinate), poly (butylene succinate), poly (butylene succinate-co-butylene adipate), etc. And aliphatic polyesters composed of a diol and a dicarboxylic acid represented by In these aliphatic polyesters, the terminal carboxyl group may be esterified with an alcohol or may be hydroxyl-substituted with a diol. Examples of the polyhydric alcohol ester include glycerin esters such as monoglyceride, diglyceride and triglyceride which are esters of glycerin and fatty acid, pentaerythritol ester and the like. Examples of polyvalent carboxylic acid esters include citric acid esters such as tributyl citrate and tributyl citrate.

  The compatibilizing agent preferably has a boiling point of 250 ° C. or higher. When the boiling point is less than 250 ° C., gas generation during molding and bleeding out from the obtained molded product may occur. The number average molecular weight is preferably in the range of 200 to 50,000, more preferably 500 to 20,000. When the molecular weight is less than 200, gas generation during molding and bleeding out from the resulting molded product are likely to occur, and the mechanical strength and heat resistance of the molded product may be impaired. When the molecular weight exceeds 50,000, the effect of improving the dispersibility of the layered silicate tends to be small.

  As a method for adding a compatibilizing agent, a method of impregnating the above compound directly into a layered silicate in advance, a method of mixing the above compound in the presence of water or an organic solvent, and then removing water or the organic solvent by filtration or the like, a polyester resin And a method of adding together with a layered silicate at the time of synthesizing a polyester resin, etc., but prior to mixing with the polyester, a method of mixing the layered silicate in advance Is preferably used.

  When a layered silicate is added to the resin composition of the present invention, a preferable dispersion state thereof is a complete delamination type in which the layers of the layered silicate are separated one by one, or an interlayer insertion type in which resin molecules are inserted between the layers. Or a mixture of these. Quantitatively, it is preferable that the average thickness of the single layer or laminated layer of a layered silicate observed with a transmission electron microscope is 1 to 100 nm, more preferably 1 to 50 nm, and still more preferably 1 to 20 nm. Alternatively, the interlayer distance of the layered silicate observed by X-ray diffraction is preferably 2.5 nm or more, more preferably 3 nm or more, still more preferably 4 nm or more, and most preferably a peak derived from the interlayer distance. Is not observed. Examples of the method for controlling the dispersibility of the layered silicate include, in the kneading method, change of kneading conditions, use of the compatibilizer described above, introduction of polar groups into the resin, and the like. In general, when a layered silicate is added during polymerization of polyester, dispersibility can be further improved.

Glass fibers may be used in the resin composition of the present invention for the purpose of improving mechanical strength and heat resistance. The blending amount is preferably 1 to 50 parts by mass, more preferably 1 to 20 parts by mass, and further preferably 1 to 10 parts by mass with respect to 100 parts by mass of polylactic acid . The glass fiber may be subjected to a surface treatment in order to improve adhesion with the resin. As an addition method, it can be added from a hopper or in the middle of kneading using a side feeder in an extruder. Moreover, it can also use by diluting with a base resin at the time of shaping | molding by carrying out a masterbatch process of glass fiber.

  As long as the properties of the resin composition of the present invention are not greatly impaired, pigments, heat stabilizers, antioxidants, weathering agents, flame retardants, plasticizers, lubricants, mold release agents, antistatic agents, fillers, crystals A nuclear material etc. can be added. Examples of heat stabilizers and antioxidants include hindered phenols, phosphorus compounds, hindered amines, sulfur compounds, copper compounds, and alkali metal halides. 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), N-containing compounds (melamine and guanidine), and inorganic compounds (borate and Mo compounds). It is done. Inorganic fillers include talc, calcium carbonate, zinc carbonate, wollastonite, silica, alumina, magnesium oxide, calcium silicate, sodium aluminate, calcium aluminate, sodium aluminosilicate, magnesium silicate, glass balloon, carbon black, Examples thereof include zinc oxide, antimony trioxide, zeolite, hydrotalcite, metal fiber, metal whisker, ceramic whisker, potassium titanate, boron nitride, graphite, and carbon fiber. Examples of the inorganic crystal core material include talc and kaolin. Examples of the organic crystal core material include a sorbitol compound, benzoic acid and a metal salt of the compound, a phosphate metal salt, and a rosin compound. In addition, the method of mixing these with the polyester resin composition of this invention is not specifically limited.

Tree fat compositions of the present invention, injection molding, blow molding, extrusion molding, inflation molding, and vacuum forming the sheet after processing, pressure forming, by a molding method such as vacuum-pressure forming can be a variety of moldings. 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, and the like can be employed. One example of injection molding conditions suitable for the resin composition the present invention, a cylinder temperature Tm or the flow initiation temperature or more trees fat composition, preferably from 180 to 280 ° C., more preferably in the range of 200 to 270 ° C. in addition, the mold temperature is suitably at most trees fat composition (Tm-20 ℃). Or become unstable operability such as a short circuit and the molding temperature is too low the shaped article occurs, prone to overload, the molding temperature is too high and decomposition tree fat composition, of a molded article obtained Problems such as reduction in strength and coloring are likely to occur.

The heat resistance of the resin composition of the present invention can be enhanced by promoting crystallization. As a method for this, for example, there is a method of promoting crystallization at cooling in the mold during injection molding, in which case, a mold temperature of dendritic fat composition (Tg + 20 ° C.) or higher, ( (Tm−20 ° C.) or less, and after maintaining for a predetermined time, cooling to Tg or less is preferable. Further, as a method for promoting crystallization after molding, it is preferable to directly heat the sample at Tg or more and (Tm−20 ° C.) or less after cooling to Tg or less.

  Specific examples of molded articles using the resin composition of the present invention include mobile phone strap parts, fan bones, buttons, golf tees, personal computer case parts and cases, mobile phone case parts and cases. In addition, resin parts for electrical appliances such as OA equipment casing parts, bumper, instrument panel, console box, garnish, door trim, ceiling, floor, engine resin parts for automobiles and the like. Moreover, it can also be set as a film, a sheet | seat, a hollow molded product, etc.

EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited only to an Example. The measuring method used for evaluation of the resin composition of an Example and a comparative example is as follows.
(1) Color tone of pellets:
Using a Σ90 color measuring system manufactured by Nippon Denshoku Industries Co., Ltd., the L, a, and b values of the resin composition pellets were measured with a C / 2 light source and reflection. The L value indicates lightness, and the a value and b value indicate chromaticity indicating hue and saturation, respectively. a is a red direction, -a is a green direction, b is a yellow direction, and -b is a blue direction. The larger the value, the brighter the color and the smaller the color, the darker the color. (Hunter Lab color system). An L value of 30 or more was considered acceptable.
(2) Deflection temperature under load (DTUL):
It was measured at a load of 0.45 MPa in accordance with ISO 75.
(3) Charpy impact strength:
Measured according to ISO 179.
(4) Flexural strength and flexural modulus:
Measured according to ISO 178.
(5) Tensile strength and elongation at break:
Measured according to ISO 527.

Moreover, the various raw materials used for the Example and the comparative example are as follows.
1. Resin raw material (1) Polylactic acid (PLA):
Unitika polylactic acid resin Terramac TE-4000 (DTUL: 58 ° C.),
TE-6100 (DTUL: 110 ° C.) was used.
(2) Polybutylene succinate (PBS):
AZ-71TN manufactured by Mitsubishi Chemical Corporation was used. In this case, a small amount of PLA component is copolymerized.

Each resin used was vacuum-dried at 70 ° C. for 24 hours.
2. Vegetable fiber material In addition, the following material performed 100 degreeC * hot air drying for 24 hours in use.
(1) Kenaf A kenaf cut to a fixed length of about 5 mm was pulverized and loosened with a turbo mill (T-250 manufactured by Matsubo) to give a diameter of 20 to 50 μm and a fiber length of 1 to 5 mm.
(Delignin treatment)
The kenaf was pressurized and heated using a sodium hydroxide solution to perform delignification treatment. (2) Wood flour A commercially available insect (beetle insect, wingworm) wood was pulverized until it became powdery using a turbo mill.
(Delignin treatment)
The wood flour was pressurized and heated using a sodium hydroxide solution to perform delignification treatment.
(3) Waste paper Newspaper was finely pulverized using a shredder, kneaded with water, solidified to a size of about 10 cm in diameter, and dried, and then crushed into pieces using a turbo mill.
(Delignin treatment)
The waste paper was pressurized and heated using a sodium hydroxide solution to perform delignification treatment.

Example 1
Using a twin screw extruder (TEM37BS type manufactured by Toshiba Machine Co., Ltd.), 85 parts by mass of TE-6100 and 15 parts by mass of kenaf subjected to delignification treatment were supplied from the root supply port of the extruder. At this time, the barrel temperature was 200 ° C., the screw rotation speed was 130 rpm, the discharge was 15 kg / h, and the extrusion was carried out while venting. The discharged resin was cut into pellets to obtain resin composition pellets.
The pellet was vacuum-dried at 70 ° C. for 24 hours, and then the color tone was measured. Moreover, the test piece for general physical property measurement (ISO type | mold) was created using IS-100E type injection molding machine by Toshiba Machine Co., Ltd., and it used for various measurements. Table 1 shows the molding conditions at this time.

Examples 2-5 and Comparative Examples 1-13
Resin composition pellets were obtained in the same manner as in Example 1 except that the amounts and types of the biodegradable resin and the vegetable fiber material were changed, and this was injection molded to measure various physical properties.

Table 1 summarizes the evaluation results of Examples 1 to 5 and Comparative Examples 1 to 13 .

  As reference examples, Table 2 shows the physical properties of the three types of resins used in Examples and Comparative Examples.

In each of Examples 1 to 5 , resin compositions excellent in the balance between color tone and physical properties were obtained. In the color tone, the L value was 30 or more. Further, by applying delignification treatment to kenaf , the reinforcement efficiency is improved along with the improvement of color tone. For example, Example 1 and Comparative Example 1, Example 2 and Comparative Example 2, and Example 4 Comparative example 5, it is apparent by comparing the etc. Comparative example 3-example 5. In Comparative Example 8, kenaf subjected to delignification treatment was used, but since it was used in a large amount beyond the range of the present invention, shear heat generation during kneading was increased, and color tone was deteriorated due to burning. In addition, the productivity deteriorated due to the decrease in workability.

Claims (2)

A resin composition comprising 50 to 95% by mass of polylactic acid and 50 to 5% by mass of kenaf subjected to delignification treatment, and having an L value of 30 or more expressed in Hunter Lab color system . The molded object formed by shape | molding the resin composition of Claim 1.