WO2014034071A1

WO2014034071A1 - Thermoplastic resin composition and molded article

Info

Publication number: WO2014034071A1
Application number: PCT/JP2013/004998
Authority: WO
Inventors: 佐藤　大輔; 陽介尾上; 熊澤　貞紀
Original assignee: 東レ株式会社
Priority date: 2012-08-31
Filing date: 2013-08-23
Publication date: 2014-03-06
Also published as: JPWO2014034071A1; JP5527489B1

Abstract

Provided is a resin composition which has excellent extrusion molding processability and injection moldability; a molded article of which has superior surface smoothness; has biodegradability, rigidity, impact resistance and heat resistance that are superbly balanced; and in which discoloration and odor are reduced. This thermoplastic resin composition comprises 1-100 parts by weight of cellulose fiber (B) with respect to 100 parts by weight of a polylactic resin (A), wherein a carboxyl terminal amount of the polylactic resin (A) in the thermoplastic resin composition is in the range of 10-100 eq/t and an average fiber diameter of the cellulose fiber (B) is in the range of 0.1-15 μm and an average fiber length of the cellulose fiber (B) is in the range of 200-800 μm.

Description

Thermoplastic resin composition and molded article

Japanese Patent Application by Toray Industries, Inc., Japanese Patent Application No. 2012-191601, Japanese Patent Application No. 2013-37098, Japanese Patent Application No. 2013-37099, Japanese Patent Application No. 2013-93477, This document is incorporated herein for reference.

The present invention relates to a thermoplastic resin composition.

In recent years, the problem of exhaustion of fossil fuels such as oil has been highlighted. In particular, as a plastic material, polylactic acid resin is attracting attention as a biopolymer because lactic acid, which is a monomer of polylactic acid resin, is produced at low cost by fermentation using microorganisms. The melting point of polylactic acid resin is as high as about 170 ° C. Polylactic acid resins are expected as biopolymers that can be melt-molded.

On the other hand, from the viewpoint of protecting the global environment, many attempts have been made to use natural organic materials such as wood powder, paper powder, bamboo powder, and kenaf as resin fillers (for example, Patent Document 1).

JP 2012-102324 A JP 2008-150599 A JP 2005-002174 A JP 2010-121131 A International Publication No. 2006/097979 Japanese Patent Laid-Open No. 2005-220171 Japanese Patent Laid-Open No. 2005-035134

The resin composition of Patent Document 1 is a resin composition containing a resin, a cellulosic fiber, and a dispersant having a hydroxyl value of 30 mgKOH / g or more, and can satisfactorily disperse the cellulosic fiber. In addition, the resin composition is excellent in mechanical strength, impact strength, and moldability. However, Patent Document 1 does not have any specific examples regarding polylactic acid resin and biodegradability. Moreover, it is difficult for the resin composition of Patent Document 1 to have a high balance of properties such as extrusion processability, injection moldability, surface smoothness of molded products, rigidity, impact resistance, and heat resistance. There was a problem.

The polylactic acid resin composition of Patent Document 2 is a polylactic acid resin composition containing a polylactic acid resin, natural fibers, and a coupling agent, and has excellent mechanical strength, heat resistance, moldability, and hue of a molded product. It is a polylactic acid resin composition. The resin composition of Patent Document 2 has a certain degree of improvement in mechanical strength, heat resistance, moldability, and hue of the molded product, but the effect is not sufficient. Furthermore, Patent Document 2 has no specific disclosure about the biodegradability of the polylactic acid resin composition. In addition, the resin composition of Patent Document 2 is highly compatible with the balance of properties such as biodegradability, extrusion processability, injection moldability, surface smoothness, rigidity, impact resistance, and heat resistance of molded products. There was a problem that it was difficult.

The resin composition of Patent Document 3 includes a crystallization accelerator, a thermoplastic resin other than a polylactic acid resin, a filler other than a natural organic filler, and a stabilizer for a polylactic acid resin and a natural organic filler. , A resin composition comprising at least one selected from a mold release agent and a carboxyl group-reactive end-blocking agent. The resin composition of Patent Document 3 is a resin composition having a certain degree of moldability, mechanical properties, and heat resistance, but its effect is not sufficient. Further, the resin composition of Patent Document 3 has problems that extrudability, coloring during molding, and odor deteriorate.

The resin composition of Patent Document 4 is a natural fiber reinforced polylactic acid resin composition containing natural fibers surface-treated with a first polylactic acid resin and a second polylactic acid resin, and the second polylactic acid resin is a first polylactic acid resin. It is a natural fiber reinforced polylactic acid resin composition containing an isomer different from the lactic acid resin. Although the resin composition of patent document 4 is a resin composition which has a certain amount of hydrolysis resistance, mechanical strength, and heat resistance, the effect is not enough. Further, the resin composition of Patent Document 4 has a problem that extrudability, coloration during molding, and odor deteriorate.

The resin composition of Patent Document 5 is a vegetable resin composition containing polylactic acid, a thermoplastic resin, and a polymer type compatibilizing agent having alkyl methacrylate as a monomer component. Although the resin composition of Patent Document 5 is a resin composition having a certain degree of impact resistance and heat resistance, its effect is not sufficient. Further, the resin composition of Patent Document 5 has a problem that it is difficult to achieve a balance between biodegradability, rigidity, impact resistance, and heat resistance.

The composition of Patent Document 6 is a lactic acid polymer composition containing a lactic acid polymer, a fibrous (needle-like) filler, and an impact modifier. Although the composition of patent document 6 has a certain amount of heat resistance and impact resistance, the effect is not enough. Moreover, the composition of patent document 6 had the subject which extrusion molding processability, the coloring at the time of a shaping | molding process, and an odor deteriorate. Furthermore, the composition of Patent Document 6 has a problem that it is difficult to achieve a balance between biodegradability, rigidity, impact resistance, and heat resistance.

The method for producing a resin composition of Patent Document 7 is a resin composition in which a polylactic acid resin and a naturally-derived organic filler are melt-kneaded using a melt-kneading apparatus under specific resin temperature, residence time, and shear rate conditions. It is a manufacturing method of a thing. Although the resin composition having a certain degree of heat resistance, appearance, and color tone can be produced by the production method of Patent Document 7, the effect is not sufficient. Further, the resin composition of Patent Document 7 has a problem that it is inferior in the balance of extrusion processability, injection moldability, biodegradability, mechanical properties, and the like.

As described above, whichever method is used, the extrusion processability and injection moldability are excellent, the surface smoothness of the molded product is excellent, and the biodegradability, rigidity, impact resistance, and heat resistance are balanced. Although it is very difficult to obtain a resin composition that is excellent and excellent in coloration and odor, there are many requests for materials that can be used practically without problems, and further improvements have been demanded.

The present invention, which is difficult in the above-described prior art, is excellent in extrusion processability and injection moldability, excellent in surface smoothness of molded products, and balanced in biodegradability, rigidity, impact resistance, and heat resistance. It is an object of the present invention to provide a resin composition that is excellent in color and has reduced coloring and odor and a molded product comprising the same.

The present invention employs the following means in order to solve such problems.

(1) (A) A thermoplastic resin composition obtained by blending 1 to 100 parts by weight of cellulose fiber to 100 parts by weight of a polylactic acid resin, wherein (A) in the thermoplastic resin composition The carboxyl terminal amount of the polylactic acid resin is in the range of 10 eq / t to 100 eq / t, (B) the average fiber diameter of the cellulose fibers is in the range of 0.1 μm to 15 μm, and the average fiber length is 200 μm to 800 μm. A thermoplastic resin composition that is within the range.

(2) The thermoplastic resin composition as described in (1) above, wherein the amount of residual metal catalyst contained in (A) the polylactic acid resin is in the range of 1 ppm to 500 ppm.

(3) The thermoplastic resin composition according to the above (1) or (2), wherein the maximum height (Ry) of the surface roughness of the extruded product made of the thermoplastic resin composition is 600 μm or less. , A thermoplastic resin composition.

(4) The thermoplastic resin composition according to any one of (1) to (3) above, further comprising (A) a weight average molecular weight of 1,000,000 to 100 parts by weight of the polylactic acid resin. A thermoplastic resin composition obtained by blending 0.1 to 20 parts by weight of (C) acrylic resin that is 7.5 million.

(5) The thermoplastic resin composition according to any one of (1) to (4) above, wherein (B) the bulk density of the cellulose fiber before blending is from 30 kg / m ³ to 200 kg / m ^A thermoplastic resin composition within the range of ³ .

(6) The thermoplastic resin composition according to any one of (1) to (5) above, further comprising (D) a crystal nucleating agent for 100 parts by weight of the polylactic acid resin. A thermoplastic resin composition comprising 0.1 to 20 parts by weight.

(7) The thermoplastic resin composition according to any one of (1) to (6) above, further comprising (E) 1 plasticizer per 100 parts by weight of the polylactic acid resin. A thermoplastic resin composition comprising 20 parts by weight.

(8) A molded article comprising the thermoplastic resin composition according to any one of (1) to (7) above.

According to the present invention, the extrusion processability and the injection moldability are excellent, the surface smoothness of the molded product is excellent, and the biodegradability, rigidity, impact resistance, and heat resistance are balanced, and the coloring and odor are further improved. Can be provided.

[(A) Polylactic acid resin]
In the embodiment of the present invention, the (A) polylactic acid resin refers to a polymer mainly composed of L-lactic acid and / or D-lactic acid, but may contain other copolymer components other than lactic acid. . Examples of structural units of other copolymer components include polycarboxylic acids, polyhydric alcohols, hydroxycarboxylic acids, and lactones. Specific examples of the constituent unit of the copolymer component include (i) oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, fumaric acid, cyclohexanedicarboxylic acid, Polycarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, anthracene dicarboxylic acid, 5-sodium sulfoisophthalic acid, 5-tetrabutylphosphonium sulfoisophthalic acid, (ii) ethylene glycol, propylene Glycol, butanediol, heptanediol, hexanediol, octanediol, nonanediol, decanediol, 1,4-cyclohexanedimethanol, neopentyl glycol, glycerin, pentaerythritol, bisphenol A, bisphenol Aromatic polyhydric alcohols obtained by addition reaction of tylene oxide, polyhydric alcohols such as diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, (iii) glycolic acid, 3-hydroxybutyric acid, 4-hydroxy Hydroxycarboxylic acids such as butyric acid, 4-hydroxyvaleric acid, 6-hydroxycaproic acid, hydroxybenzoic acid, and (iv) glycolide, ε-caprolactone glycolide, ε-caprolactone, β-propiolactone, δ-butyrolactone, β- Alternatively, lactones such as γ-butyrolactone, pivalolactone, and δ-valerolactone can be used. The content of the copolymer component is preferably 0 to 30 mol%, preferably 0 to 10 mol%, based on 100 mol% of all monomers. Is more preferable.

In the embodiment of the present invention, it is preferable to use (A) a polylactic acid resin in which the optical purity of the lactic acid component is high in terms of moldability and heat resistance. That is, (A) Of the total lactic acid component of the polylactic acid resin, it is preferable that the L-form is contained in 80% or more, or the D-form is contained in 80% or more, and the L-form is contained in 90% or more or More preferably 90% or more, more preferably 95% or more of L isomer or 95% or more of D isomer, 98% or more of L isomer or 98% or more of D isomer Most preferably. Moreover, the upper limit of the content of L-form or D-form is usually 100% or less.

In the embodiment of the present invention, it is preferable to use a polylactic acid stereocomplex as the (A) polylactic acid resin in terms of moldability and heat resistance. Examples of a method for forming a polylactic acid stereocomplex include melt-kneading, solid-phase kneading, or solution mixing of poly-L-lactic acid having 90% or more of L-form and poly-D-lactic acid having 90% or more of D-form. The method of mixing using the method of can be mentioned. In terms of heat resistance, the poly-L-lactic acid L form is preferably 95%, more preferably 98% or more. In addition, the D-form of poly-D-lactic acid is preferably 95%, more preferably 98% or more from the viewpoint of heat resistance.

As another method for forming a polylactic acid stereocomplex, a method of forming a block copolymer from a poly-L-lactic acid segment and a poly-D-lactic acid segment can also be mentioned. From the viewpoint that a polylactic acid stereocomplex can be easily formed, a method of forming a block copolymer comprising a poly-L-lactic acid segment and a poly-D-lactic acid segment is preferred. In addition, as the (A) polylactic acid resin, a polylactic acid stereocomplex may be used alone, or a polylactic acid stereocomplex and poly-L-lactic acid or poly-D-lactic acid may be used in combination.

In the embodiment of the present invention, (A) the molecular weight and molecular weight distribution of the polylactic acid resin are not particularly limited as long as they can be substantially molded. The weight average molecular weight is preferably 10,000 or more, more preferably 50,000 or more, further preferably 100,000 or more, and particularly preferably 200,000 from the viewpoint that the phase structure can be easily controlled and the impact resistance is improved. That is good. (A) The upper limit of the weight average molecular weight of the polylactic acid resin is not particularly limited, but is preferably 800,000 or less, more preferably 600,000 or less, and still more preferably 400,000 or less. Here, the weight average molecular weight of (A) polylactic acid resin refers to polymethyl methacrylate (PMMA) measured by gel permeation chromatography (GPC, “Water Model 510” manufactured by Waters) using hexafluoroisopropanol as a solvent. It is a weight average molecular weight in terms of conversion.

In the embodiment of the present invention, (A) the melting point of the polylactic acid resin is not particularly limited, but is preferably 120 ° C. or higher, and more preferably 150 ° C. or higher.

In the embodiment of the present invention, as a method for producing the (A) polylactic acid resin, a known polymerization method can be used. (A) As a manufacturing method of polylactic acid resin, the direct polymerization method from lactic acid, the ring-opening polymerization method via lactide, etc. can be used, for example.

In the embodiment of the present invention, a catalyst can be used for the polymerization of (A) polylactic acid resin. As the catalyst, either a metal catalyst or a non-metal catalyst may be used, but a metal catalyst is preferable.

In the embodiment of the present invention, when a metal catalyst is used, the amount of the residual metal catalyst contained in the polylactic acid resin (A) in the resin composition is represented by the content of the metal contained in the metal catalyst added during the polymerization. As a metal catalyst, well-known metal catalysts, such as a tin compound, a titanium compound, a lead compound, a zinc compound, a cobalt compound, an iron compound, a lithium compound, can be used.

In the embodiment of the present invention, the amount of carboxyl terminal of (A) polylactic acid resin in the resin composition to be described later is controlled by controlling the amount of residual catalyst of (A) polylactic acid resin. A resin composition having excellent physical properties and having a higher biodegradation rate than (A) a polylactic acid resin alone can be produced.

In the embodiment of the present invention, the amount of the residual metal catalyst of the (A) polylactic acid resin is preferably 1 ppm or more, more preferably 5 ppm or more, and more preferably 10 ppm or more from the viewpoint that biodegradability and mechanical properties of the molded product are improved. More preferred is 10 ppm or more. In view of improving biodegradability and mechanical properties of the molded product, the residual metal catalyst amount of (A) polylactic acid resin is preferably 500 ppm or less, more preferably 400 ppm or less, further preferably 300 ppm or less, and particularly preferably 100 ppm. . When the amount of the residual metal catalyst is in the range of 1 ppm to 500 ppm, it is preferable in terms of improving biodegradability and mechanical properties of the molded product. Here, (A) the amount of the residual metal catalyst of the polylactic acid resin was determined by (A) heat-decomposing the polylactic acid resin with nitric acid and sulfuric acid and then heating and dissolving with dilute nitric acid. CID-AP ").

[(A) Amount of carboxyl terminal of polylactic acid resin]
In the embodiment of the present invention, the (A) carboxyl terminal amount of the polylactic acid resin means the carboxyl terminal amount of the (A) polylactic acid resin before melt kneading. (A) The method for measuring the carboxyl end amount of a polylactic acid resin is that 1 g of (A) polylactic acid resin is sampled and dissolved in 50 mL of a mixture of o-cresol: chloroform = 2: 1, and then 0.05 mol / L ethanol. This is a method of measuring by titration with basic potassium hydroxide.

In the embodiment of the present invention, the carboxyl terminal amount of (A) polylactic acid resin is such that the carboxyl terminal amount of (A) polylactic acid resin in the thermoplastic resin composition to be described later is within the range of 10 eq / t to 100 eq / t. If so, there is no particular limitation. As for the carboxyl terminal amount of (A) polylactic acid resin in a thermoplastic resin composition, 15 eq / t or more is especially preferable. Moreover, 50 eq / t or less is preferable, as for the carboxyl terminal amount of (A) polylactic acid resin in a thermoplastic resin composition, 40 eq / t or less is more preferable, and 30 eq / t or less is especially preferable. (A) By making the carboxyl terminal amount of the polylactic acid resin within the range of 10 eq / t to 100 eq / t, (A) the carboxyl terminal of the polylactic acid resin and (B) the hydroxyl terminal of the cellulose fiber react appropriately. As a result, mechanical properties such as extrusion processability, injection moldability, strength, rigidity, impact resistance, and heat resistance are improved.

[(B) Cellulose fiber]
In the embodiment of the present invention, examples of the (B) cellulose fiber include natural cellulose fiber, regenerated cellulose fiber, purified cellulose fiber, and semi-synthetic cellulose fiber. Natural cellulose fibers include seed hair fibers such as cotton, kapok, acund, blue bacyclomon, green hemp, flax, rush, icy, Indian hemp, eneda, jute, ramie, and kenaf (marine). Plant fibers made of bast fibers such as sisal hemp, hemp, panga, bontenka, manila hemp, palm fiber, roselle and the like. Examples of regenerated cellulose fibers include rayon, “polynosic”, “cupra”, and nitrocellulose. Examples of the purified cellulose fiber include “Tencel” and “Lyocell”. Semi-synthetic cellulose fibers include (i) organic acid esters such as cellulose acetate (cellulose acetate), cellulose propionate, cellulose butyrate, cellulose acetate propionate, and cellulose acetate butyrate, (ii) cellulose nitrate, and cellulose sulfate. , Inorganic acid esters such as cellulose phosphate, (iii) mixed acid esters such as cellulose nitrate acetate, (iv) hydroxyalkyl cellulose, carboxyalkyl cellulose, alkyl cellulose and the like.

In the embodiment of the present invention, (B) the average fiber diameter of the cellulose fibers is 0.1 μm or more, more preferably 1 μm or more, and particularly preferably 5 μm or more. When the average fiber diameter is smaller than 0.1 μm, the mechanical properties of the molded product are deteriorated. Moreover, the average fiber diameter of (B) cellulose fiber is 15 micrometers or less, 14 micrometers or less are more preferable, and 13 micrometers or less are especially preferable. When the average fiber diameter is larger than 15 μm, the extrusion processability, the balance of mechanical properties, and the supply property at the time of melt kneading deteriorate. By setting the average fiber diameter in the range of 0.1 to 15 μm, mechanical properties such as bending elastic modulus and heat resistance of the molded product and extrusion processability are balanced and excellent.

In the embodiment of the present invention, (B) the average fiber length of the cellulose fibers is 200 μm or more, more preferably 300 μm or more, and particularly preferably 400 μm or more. When the average fiber length is smaller than 200 μm, it is not preferable in that the mechanical properties of the molded product are deteriorated. Moreover, (B) The average fiber length of a cellulose fiber is 800 micrometers or less, 600 micrometers or less are more preferable, and 500 micrometers or less are especially preferable. When the average fiber length is larger than 800 μm, the extrusion processability and the supply property at the time of melt kneading are not preferable. By setting the average fiber length in the range of 200 to 800 μm, mechanical properties such as flexural modulus and heat resistance of the molded product and extrusion processability are balanced and excellent.

Here, the average fiber length of the (B) cellulose fiber is an average fiber length measured using “MorFI Fiber Analyzer” manufactured by Techpap. In addition, (B) the average fiber diameter of the cellulose fiber is determined by measuring using a “Vibrodyn Fiber Fiber Analyzer” manufactured by Lenzing Technique Instruments Co., Ltd., and determining the titer based on the density. The fiber diameter. In the present embodiment, “titer” is a measure of the thickness of the fiber.

(B) The average fiber length and average fiber diameter of the cellulose fibers are not changed even in the thermoplastic resin composition. The thermoplastic resin composition is dissolved in a good solvent (such as chloroform), (A) the polylactic acid resin and (B) the cellulose fiber are separated, and the dried (B) average fiber length and average fiber diameter of the cellulose fiber are determined. By measuring on the said conditions, it can confirm that there is no change also in a thermoplastic resin composition.

In the embodiment of the present invention, the (B) cellulose fiber is preferably a purified cellulose fiber from the viewpoint that the bulk density and fiber length are controllable and from the viewpoint that the odor and coloring of the melt-kneaded resin composition are reduced. .

In an embodiment of the present invention, the bulk density of the previous (B) cellulosic fibers to be blended is preferably 30kg / m ³ or more, more preferably 40 kg / m ³ or more, more preferably 50 kg / m ³ or more, 70 kg / m ³ or more is particularly preferable, and 100 kg / m ³ or more is most preferable. The bulk density of the previous (B) cellulosic fibers to be blended is preferably from 200 kg / m ³ or less, more preferably 150 kg / m ³ or less, more preferably 140 kg / m ³ or less. When the bulk density is in the range of 30 kg / m ³ to 200 kg / m ³ , there is no problem in the supply property at the time of melt kneading, and the dispersibility of (B) cellulose fibers in the resin composition after melt kneading is improved. It is preferable in terms of improving injection moldability and mechanical properties.

Here, the bulk density of the (B) cellulose fiber is a value measured using a “Powder Tester” manufactured by Hosokawa Micron Corporation in a 23 ° C., 50% RH (RelativeＲHumidity) environment.

In the embodiment of the present invention, the blending amount of (B) cellulose fiber is 1 part by weight or more, more preferably 5 parts by weight or more, and particularly preferably 10 parts by weight or more. Moreover, the compounding quantity of (B) cellulose fiber is 100 weight part or less, 95 weight part or less is more preferable, and 90 weight part or less is especially preferable. When the blending amount is 1 part by weight or more, the mechanical properties of the molded product are improved. Further, when the blending amount is 100 parts by weight or less, the fuzz of the strands during melt-kneading is reduced, and deterioration of extrusion processability due to strand breakage can be prevented.

In the embodiment of the present invention, the crystallinity of the (B) cellulose fiber is preferably 50% or more, more preferably 55% or more, and most preferably 60% or more in terms of excellent injection moldability, rigidity, and heat resistance. It is. The crystallinity referred to here is cellulose I-type crystallinity calculated by the Segal method from the diffraction intensity value by the X-ray diffraction method. The degree of crystallinity is derived from the following calculation formula (1). In addition, “RINT2000 / PC” manufactured by Rigaku Corporation is used as the X-ray diffraction apparatus used for the X-ray diffraction method.

Cellulose type I crystallinity (%) = {(I22.6−I18.5) /I22.6} × 100 (1)
(Where I22.6 is the diffraction intensity of the lattice plane (002 plane) (diffraction angle 2θ = 22.6 °) in X-ray diffraction, and I18.5 is the amorphous portion (diffraction angle 2θ = 18.5 °). Shows diffraction intensity)

In the embodiment of the present invention, the dispersion state of the (B) cellulose fiber in the resin composition is not particularly limited, but the (B) cellulose fiber in the resin composition is improved in terms of improved extrusion processability and mechanical properties. However, it is preferable that (C) a molecular chain of the acrylic resin, which will be described later, is physically entangled moderately.

[Maximum height (Ry) of surface roughness of an extruded product made of a thermoplastic resin composition]
The maximum height (Ry) of the surface roughness of the extrusion molded product comprising the thermoplastic resin composition of the embodiment of the present invention is 600 μm in that it is excellent in extrusion processability, injection moldability, and surface appearance of the molded product. Or less, more preferably 550 μm or less, and most preferably 500 μm or less. As used herein, Ry refers to an extruded product having a diameter of 3 mm and a length of 10 mm of an extruded strand having a surface of 5 mm, using a surface roughness measuring machine “SV-2100” manufactured by Mitutoyo Corporation, and JIS B 0601 (1994). ), A cutoff value (λc): a maximum height (Ry) measured at 0.8 mm.

[(C) Acrylic resin]
In the embodiment of the present invention, it is preferable to blend (C) an acrylic resin in terms of excellent extrusion processability, injection moldability, surface appearance of a molded product, and mechanical properties. (C) The weight average molecular weight of the acrylic resin is preferably 1 million or more, more preferably 2 million or more, and most preferably 3 million or more. The weight average molecular weight of the (C) acrylic resin is preferably 7.5 million or less, more preferably 6 million or less, and most preferably 5 million or less. If the weight average molecular weight of (C) acrylic resin is in the range of 1,000,000 to 7.5 million, physical entanglement between (B) cellulose fibers and (C) acrylic resin molecular chains will increase, and extrusion molding will occur. This is preferable in terms of improving workability, injection moldability, surface appearance of molded products, and mechanical properties.

The weight average molecular weight of the (C) acrylic resin here is polymethyl methacrylate (PMMA) measured by gel permeation chromatography (GPC, “Water Model 510” manufactured by Waters) using hexafluoroisopropanol as a solvent. It is a weight average molecular weight in terms of conversion.

In the embodiment of the present invention, the (C) acrylic resin is a polymer of alkyl (meth) acrylate and / or a copolymer of alkyl (meth) acrylate.

Examples of alkyl (meth) acrylate include methyl methacrylate, methyl acrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, cyclohexyl methacrylate, hydroxyethyl methacrylate, glycidyl methacrylate, allyl methacrylate, Aminoethyl acrylate, propylaminoethyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, glycidyl acrylate, dicyclopentenyloxyethyl acrylate, dicyclopentanyl acrylate, butanediol diacrylate, diacryl Acid nonanediol, polyethylene glycol diacrylate, methyl 2- (hydroxymethyl) acrylate, ethyl 2- (hydroxymethyl) acrylate, methacrylic acid, methacrylate Ethyl phosphate, butyl methacrylate, cyclohexyl methacrylate, dimethylaminoethyl methacrylate, ethylaminopropyl methacrylate, phenylaminoethyl methacrylate, cyclohexylaminoethyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxy methacrylate Propyl, glycidyl methacrylate, dicyclopentenyloxyethyl methacrylate, dicyclopentanyl methacrylate, pentamethylpiperidyl methacrylate, tetramethylpiperidyl methacrylate, benzyl methacrylate, ethylene glycol dimethacrylate, propylene glycol dimethacrylate, di Examples include polyethylene glycol methacrylate, and one or more of these alkyl (meth) acrylates can be used.

Also, a copolymer obtained by copolymerizing an alkyl (meth) acrylate and other vinyl monomers can be used as the (C) acrylic resin. Other vinyl monomers include aromatic vinyl monomers such as α-methyl styrene, o-methyl styrene, p-methyl styrene, o-ethyl styrene, p-ethyl styrene, pt-butyl styrene. , Vinyl cyanide monomers such as acrylonitrile, methacrylonitrile, ethacrylonitrile, glycidyl itaconate, allyl glycidyl ether, styrene-p-glycidyl ether, p-glycidyl styrene, maleic anhydride, maleic acid monoethyl ester N-substituted maleimides such as itaconic acid, itaconic anhydride, glutaric anhydride, N-methylmaleimide, N-ethylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, acrylamide, methacrylamide, N-methylacrylamide, Butoxymethyl Kurylamide, N-propylmethacrylamide, N-vinyldiethylamine, N-acetylvinylamine, allylamine, methallylamine, N-methylallylamine, p-aminostyrene, 2-isopropenyl-oxazoline, 2-vinyl-oxazoline, 2-acryloyl -Oxazoline, 2-styryl-oxazoline and the like. These vinyl monomers can be used alone or in combination of two or more.

Also, a copolymer containing a cyclic structural unit such as a lactone ring, maleic anhydride, glutaric anhydride or the like in the main chain can be used as the (C) acrylic resin.

(C) The acrylic resin used in the embodiment of the present invention contains a methyl methacrylate component unit as a main component. (C) The acrylic resin is preferably a polymethyl methacrylate resin containing 70% or more of a methyl methacrylate component unit, more preferably a polymethyl methacrylate resin containing 80% or more, and more preferably 90%. A polymethyl methacrylate-based resin including the above, most preferably polymethyl methacrylate.

In the embodiment of the present invention, the blending amount of the (C) acrylic resin is 0.1 parts by weight or more, more preferably 0.5 parts by weight or more, with respect to 100 parts by weight of the (A) polylactic acid resin. More preferably, it is 1 part by weight or more. Moreover, the compounding quantity of (C) acrylic resin is 20 parts weight or less with respect to 100 weight part of (A) polylactic acid resin, More preferably, it is 15 parts weight or less, More preferably, it is 10 parts weight or less. . (C) If the blending amount of the acrylic resin is 0.1 to 20 parts by weight, it is preferable in terms of improving the balance of extrusion processability, injection moldability, surface appearance of the molded product, and mechanical properties.

In the embodiment of the present invention, the glass transition temperature of the (C) acrylic resin is preferably 60 ° C or higher, more preferably 70 ° C or higher, further preferably 80 ° C or higher, particularly preferably 90 ° C or higher, and 100 ° C or higher. Most preferred. (C) Although the upper limit of the glass transition temperature of acrylic resin is not specifically limited, 150 degreeC or less is preferable at the point of extrusion moldability and injection moldability. The glass transition temperature here is a value of the glass transition temperature measured by “DSC-7” manufactured by Perkin Elmer as a differential scanning calorimeter (DSC), and the specific heat capacity change in the glass transition temperature region is a half value. Temperature.

In the embodiment of the present invention, as (C) what is marketed as an acrylic resin, for example, Metablene P series manufactured by Mitsubishi Rayon Co., PARALOID K series manufactured by Dow Chemical Co., and Kaneace PA series manufactured by Kaneka Co., Ltd. Etc.

[(D) Crystal nucleating agent]
In the embodiment of the present invention, the (D) crystal nucleating agent means one or more crystal nucleating agents selected from an inorganic crystal nucleating agent and an organic crystal nucleating agent.

In the embodiment of the present invention, specific examples of the inorganic crystal nucleating agent include talc, kaolinite, montmorillonite, mica, synthetic mica, clay, zeolite, silica, graphite, carbon black, zinc oxide, magnesium oxide, calcium oxide, Examples thereof include titanium oxide, calcium sulfide, boron nitride, magnesium carbonate, calcium carbonate, barium sulfate, aluminum oxide, neodymium oxide, and metal salts of phenylphosphonate. These inorganic crystal nucleating agents may be used alone or in combination of two or more. Talc, kaolinite, montmorillonite, mica and synthetic mica are preferred in that the effect of improving heat resistance is great, and talc is more preferred in terms of moldability. These inorganic crystal nucleating agents are preferably modified with an organic substance in order to improve dispersibility in the resin composition.

In the embodiment of the present invention, specific examples of the organic crystal nucleating agent include sodium benzoate, potassium benzoate, lithium benzoate, calcium benzoate, magnesium benzoate, barium benzoate, lithium terephthalate, sodium terephthalate, Potassium terephthalate, calcium oxalate, sodium laurate, potassium laurate, sodium myristate, potassium myristate, calcium myristate, sodium octacosanoate, calcium octacosanoate, sodium stearate, potassium stearate, lithium stearate, calcium stearate , Magnesium stearate, barium stearate, sodium montanate, calcium montanate, sodium toluate, sodium salicylate, salicylic acid Organic carboxylic acid metal salts such as sodium, zinc salicylate, aluminum dibenzoate, potassium dibenzoate, lithium dibenzoate, sodium β-naphthalate and sodium cyclohexanecarboxylate, organic sulfonic acids such as sodium p-toluenesulfonate and sodium sulfoisophthalate Salt, ethylene bis stearamide, ethylene bis laurate amide, palmitic amide, hydroxy stearic amide, erucic amide, trimesic acid tris (t-butylamide) and other carboxylic acid amides, ethylene-acrylic acid or methacrylic acid copolymer Sodium salt or potassium salt of a polymer having a carboxyl group such as sodium salt, sodium salt of styrene-maleic anhydride copolymer (so-called iono) ), Benzylidene sorbitol and derivatives thereof, phosphorus compound metal salts such as sodium-2,2′-methylenebis (4,6-di-t-butylphenyl) phosphate, and 2,2-methylbis (4,6-di-). t-butylphenyl) sodium and the like. These organic crystal nucleating agents can be used alone or in combination of two or more. From the viewpoint that the effect of improving injection moldability and heat resistance is great, organic carboxylic acid metal salts and carboxylic acid amides are preferred.

In the embodiment of the present invention, the average particle diameter of the (D) crystal nucleating agent used as a raw material is preferably 0.001 μm or more, more preferably 0.01 μm or more, and 0.1 μm or more. More preferably. In addition, the average particle diameter of the (D) crystal nucleating agent is preferably 20 μm or less, more preferably 10 μm or less, and even more preferably 5 μm or less. Here, the average particle diameter of the (D) crystal nucleating agent is a numerical value of D50 measured by “SALD-2000J” manufactured by Shimadzu Corporation.

In the embodiment of the present invention, it is preferable in terms of moldability, impact resistance and heat resistance to improve the dispersibility of the (D) crystal nucleating agent in the resin composition. Moreover, since the dispersibility of the (D) crystal nucleating agent in the resin composition can be improved as the average particle size of the (D) crystal nucleating agent is smaller, the injection moldability, impact resistance, and heat resistance are improved. More preferable in terms.

In the embodiment of the present invention, the blending amount of the (D) crystal nucleating agent is preferably 0.1 parts by weight or more, more preferably 0.3 parts by weight or more, based on 100 parts by weight of the (A) polylactic acid resin. .5 parts by weight or more is particularly preferable. Further, the blending amount of the (D) crystal nucleating agent is preferably 20 parts by weight or less, more preferably 15 parts by weight or less, and particularly preferably 10 parts by weight or less with respect to 100 parts by weight of the (A) polylactic acid resin. When the blending amount is in the range of 0.1 to 20 parts by weight, it is preferable from the viewpoint of improving mechanical properties such as injection moldability, bending elastic modulus and heat resistance.

[(E) Plasticizer]
In the embodiment of the present invention, the (E) plasticizer includes a polyester plasticizer, a glycerin plasticizer, a polycarboxylic acid ester plasticizer, a polyalkylene glycol plasticizer, an epoxy plasticizer, and a castor oil plasticizer. An agent etc. can be mentioned.

In the embodiment of the present invention, examples of the polyester plasticizer include acid components such as adipic acid, sebacic acid, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, propylene glycol, 1,3-butanediol, And polyesters composed of diol components such as 1,4-butanediol, 1,6-hexanediol, ethylene glycol and diethylene glycol, and polyesters composed of hydroxycarboxylic acid such as polycaprolactone. These polyester plasticizers may be end-capped with a monofunctional carboxylic acid or monofunctional alcohol, or may be end-capped with an epoxy compound or the like.

In the embodiment of the present invention, specific examples of the glycerin plasticizer include glycerin monoacetomonolaurate, glycerin diacetomonolaurate, glycerin monoacetomonostearate, glycerin diacetomonooleate, glycerin monoacetomonomontanate or glycerin. A triacetate etc. can be mentioned. The glycerin plasticizer may be one to which an alkylene oxide unit such as ethylene oxide or propylene oxide is added, such as polyoxyethylene glycerin triacetate. Specific examples of the glycerin plasticizer include diglycerin palmitic acid ester, diglycerin stearic acid ester, diglycerin oleic acid ester, decaglycerin palmitic acid ester, decaglycerin stearic acid ester, decaglycerin oleic acid ester and the like. A glycerin fatty acid ester is mentioned.

In the embodiment of the present invention, the polyvalent carboxylic acid plasticizer includes phthalate esters such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, dioctyl phthalate, diheptyl phthalate, dibenzyl phthalate, and butyl benzyl phthalate. , Succinic acid esters such as tributyl trimellitic acid, trioctyl trimellitic acid, trihexyl trimellitic acid, trihexyl trimellitic acid, isodecyl succinate, triethylene glycol monomethyl ether succinate, benzyl methyl diglycol succinate, adipic acid Diisodecyl, adipic acid n-octyl-n-decyl ester, adipic acid diethylene glycol monomethyl ether ester, adipic acid methyl diglycol butyl diglycol ester, adipic acid Adipic acid esters such as benzyl methyl diglycol ester and benzylbutyl diglycol adipate, azelaic acid esters such as di-2-ethylhexyl azelate, sebacic acid esters such as dibutyl sebacate and di-2-ethylhexyl sebacate, etc. Can be mentioned.

In the embodiment of the present invention, the polyalkylene glycol plasticizer includes polyethylene glycol, polypropylene glycol, poly (ethylene oxide / propylene oxide) block and / or random copolymer, polytetramethylene glycol, ethylene oxide addition polymer of bisphenols. And polyalkylene glycols such as propylene oxide addition polymers of bisphenols and tetrahydrofuran addition polymers of bisphenols or end-capping compounds such as terminal epoxy-modified compounds or terminal ether-modified compounds thereof. (E) The plasticizer is preferably polyethylene glycol, polypropylene glycol, poly (ethylene oxide / propylene oxide) block and / or random copolymer from the viewpoint of heat resistance.

In the embodiment of the present invention, the epoxy plasticizer generally refers to an epoxy triglyceride composed of an alkyl epoxy stearate and soybean oil, but in addition, mainly bisphenol A and epichlorohydrin are used as raw materials. Such so-called epoxy resins can also be mentioned.

In the embodiment of the present invention, the castor oil plasticizer may be any castor oil and derivatives thereof, such as castor oil, dehydrated castor oil, castor oil, castor oil fatty acid, dehydrated castor oil fatty acid, Ricinoleic acid, ricinoleic acid, 12-hydroxystearic acid, sebacic acid, undecylenic acid, heptyl acid, castor oil fatty acid condensate, castor oil fatty acid ester, methyl ricinolate, ethyl ricinolate, isopropyl ricinolate, butyl ricinolate, ethylene glycol Monolysylate, propylene glycol monolysylate, trimethylolpropane monolysylate, sorbitan monolysylate, castor oil fatty acid polyethylene glycol ester, castor oil ethylene oxide adduct, castor oil-based polyol, castor oil-based toll , And the like Lumpur or castor oil diol. (E) As a plasticizer, castor oil fatty acid ester, methyl ricinolate, ethyl ricinolate, isopropyl ricinolate, butyl ricinolate, ethylene glycol monoricylate, propylene glycol monoricylate, trimethylolpropane are used in terms of transparency. Monolithic acid, sorbitan monoricylate, castor oil fatty acid polyethylene glycol ester, castor oil ethylene oxide adduct, castor oil-based polyol, castor oil-based toluol or castor oil-based diol are preferred.

Other plasticizers include neopentyl glycol dibenzoate, diethylene glycol dibenzoate, triethylene glycol di-2-ethylbutyrate, polyoxyethylene diacetate, polyoxyethylene di (2-ethylhexanoate), poly Polyol esters such as oxypropylene monolaurate, polyoxypropylene monostearate, polyoxyethylene dibenzoate, polyoxypropylene dibenzoate, aliphatic carboxylic acid esters such as butyl oleate, triethyl acetylcitrate, tributyl acetylcitrate, Oxyacid esters such as ethoxycarbonylmethyldibutyl citrate, di-2-ethylhexyl citrate, methyl acetylricinoleate or butyl acetylricinoleate, large Oil, soybean oil fatty acid, soybean oil fatty acid ester, epoxidized soybean oil, rapeseed oil, rapeseed oil fatty acid, rapeseed oil fatty acid ester, epoxidized rapeseed oil, linseed oil, linseed oil fatty acid, linseed oil fatty acid ester, epoxidized linseed oil, coconut oil or palm Examples include vegetable oil-based compounds such as oil fatty acid, pentaerythritol, sorbitol, polyacrylic acid ester, silicone oil or paraffins.

In the embodiment of the present invention, the plasticizer (E) may be one kind or a combination of two or more kinds, but it may contain two or more kinds in terms of moldability, transparency and heat resistance. Preferably, at least one is a polyalkylene glycol plasticizer. In addition, as the plasticizer (E), two or more polyalkylene glycol plasticizers can be used in combination.

In the embodiment of the present invention, the amount of the plasticizer (E) is preferably 1 part by weight or more with respect to 100 parts by weight of the polylactic acid resin (A) in terms of injection moldability, heat resistance and impact resistance. 2 parts by weight or more is more preferable, and 3 parts by weight or more is particularly preferable. The blending amount of the plasticizer (E) is preferably 20 parts by weight or less and 100 parts by weight or less with respect to 100 parts by weight of the polylactic acid resin (A) in terms of injection moldability, heat resistance and impact resistance. More preferably, it is more preferably 15 parts by weight or less, and particularly preferably 10 parts by weight or less. When the blending amount is in the range of 1 to 20 parts by weight, it is preferable from the viewpoint of improving mechanical properties such as injection moldability, bending elastic modulus and heat resistance.

[(F) (A) Polylactic acid resin and (C) Thermoplastic resin other than acrylic resin]
In the embodiment of the present invention, it is also preferable that a thermoplastic resin other than (F) (A) polylactic acid resin and (C) acrylic resin is appropriately blended as necessary.

In the embodiment of the present invention, specific examples of the thermoplastic resin other than (F) (A) polylactic acid resin and (C) acrylic resin include, for example, polypropylene resin, polyethylene resin, ethylene / α-olefin copolymer. ("/" Indicates copolymerization) such as olefin resin, polystyrene resin, styrene / acrylonitrile copolymer, acrylonitrile / butadiene / styrene copolymer (ABS resin), methyl (meth) acrylate / styrene copolymer Styrene resins such as coalescence, polyvinyl alcohol resins, polyester resins other than polylactic acid resins, polycarbonate resins, polyamide resins, polyphenylene oxide resins, modified polyphenylene oxide resins, polyphenylene sulfide resins, polyoxymethylene resins, phenoxy resins , Feno Etc. Le resins. In addition, the thermoplastic resin other than (F) (A) polylactic acid resin and (C) acrylic resin may be used alone or in combination of two or more.

In the embodiment of the present invention, when a thermoplastic resin other than (F) (A) polylactic acid resin and (C) acrylic resin is included, the blending amount of (F) thermoplastic resin is (A) polylactic acid resin 100. The amount is preferably 1 part by weight or more, more preferably 2 parts by weight or more, most preferably 3 parts by weight or more, preferably 200 parts by weight or less, more preferably 150 parts by weight or less, most preferably 100 parts by weight. Less than parts by weight.

[Other additives]
In the embodiment of the present invention, as a normal additive, for example, a filler different from an inorganic crystal nucleating agent among (B) cellulose fiber and (D) crystal nucleating agent within a range not impairing the object of the present invention ( Glass fiber, carbon fiber, metal fiber, natural fiber, organic fiber, glass flake, glass bead, ceramic fiber, ceramic bead, asbestos, wollastonite, sericite, bentonite, dolomite, fine silicate, feldspar powder, potassium titanate, Shirasu balloon, aluminum silicate, silicon oxide, gypsum, novaculite, dosonite or clay, catalyst deactivators (hindered phenol compounds, thioether compounds, vitamin compounds, triazole compounds, polyamine compounds, hydrazine) Derivative compounds, phosphorus compounds, etc.), UV absorption Agents (resorcinol, salicylate, benzotriazole, benzophenone, etc.), heat stabilizers (hindered phenol, hydroquinone, phosphites and their substitutes, etc.), lubricants, mold release agents (montanic acid and its salts, esters, Colorants including half esters, stearyl alcohol, stearamide and polyethylene wax), dyes (such as nigrosine) and pigments (such as cadmium sulfide, phthalocyanine), anti-coloring agents (such as phosphites and hypophosphites), silanes Coupling agent (epoxy silane coupling agent, amino silane coupling agent, (meth) acryl silane coupling agent, isocyanate silane coupling agent, etc.), flame retardant (red phosphorus, phosphate ester, brominated polystyrene, brominated polyphenylene ester) Tellurium, brominated polycarbonate, aluminum hydroxide, magnesium hydroxide, melamine and cyanuric acid or salts thereof, silicon compounds, etc.), conductive agent or colorant (carbon black, etc.), slidability improver (graphite, fluororesin, etc.) , Antistatic agents, epoxy compounds (glycidyl ether compounds, glycidyl ester compounds, polymer compounds obtained by grafting or copolymerizing glycidyl compounds), acid anhydride compounds (maleic anhydride, succinic anhydride, acid anhydrides grafted or co-polymerized) Polymerized polymer compound), carbodiimide compound (N, N′-di-2,6-diisopropylphenylcarbodiimide, 2,6,2 ′, 6′-tetraisopropyldiphenylcarbodiimide, polycarbodiimide, etc.) Add more seeds Can do.

The blending amount of the other additives is preferably 0.01 parts by weight or more, more preferably 0.05 parts by weight or more, and most preferably 0.1 parts by weight with respect to 100 parts by weight of the (A) polylactic acid resin. The amount is preferably 100 parts by weight or less, more preferably 80 parts by weight or less, and most preferably 50 parts by weight or less.

[Production method]
In the embodiment of the present invention, as a method for producing the thermoplastic resin composition, a method of uniformly melting and kneading using a single screw extruder or a twin screw extruder, a method of volatilizing a solvent after mixing in a solution, or the like. The method of removing can be preferably used, but a method of uniformly melting and kneading using a single screw extruder or a twin screw extruder is more preferable, and a method of uniformly melting and kneading using a twin screw extruder is particularly preferable. preferable.

In the embodiment of the present invention, examples of the type of the twin screw extruder include a different direction type and a same direction type with respect to the rotational direction of the twin screw. In addition, regarding the meshing of the biaxial screw, there are a meshing type and a non-meshing type. As the type of the twin screw extruder, the same direction type and the meshing type are preferable. Further, examples of the screw used include a single screw, a double screw, and a triple screw, but a double screw is preferable.

In the embodiment of the present invention, it is preferable to use a weight type feeder as a method of supplying the raw material. Examples of the weight type feeder include a screw type, a vibration type, and a belt type, and a screw type weight feeder is preferable. Moreover, although the short axis and the biaxial are mentioned as the screw of a screw type weight feeder, both can be used.

In an embodiment of the present invention, using a weight type feeder, (A) a polylactic acid resin is supplied from a main feeder installed at the root of an extruder, and (B) a cellulose fiber is supplied from a side feeder. When supplying (C) acrylic resin, (D) crystal nucleating agent, (E) plasticizer, (F) thermoplastic resin and other additives as required, either main feeder or side feeder Supplied from

In addition, as a method of supplying the (B) cellulose fiber to the side feeder, it is preferable to supply using a weight type raw material feeder with an agitator. A screw type weight feeder is taken as an example of the raw material feeder. The screw-type weight feeder is provided with a hopper that accumulates raw materials at the upper part of the screw of the weight feeder, and normally the raw material is pushed out from the hopper by its own weight and supplied to the screw. However, since the (B) cellulose fiber is bulky, there arises a problem that it is bridged (poor supply) in the hopper and cannot be quantitatively supplied from the screw. For this reason, it is preferable to use a rotary blade for stirring the raw material inside the feeder, that is, a weight type raw material feeder with an agitator.

In an embodiment of the present invention, L / D (L: extruder screw length, D: extruder screw diameter) of the twin screw extruder is preferably 10 or more, more preferably 20 or more, and further preferably 30 or more, 90 or less is preferable, 80 or less is more preferable, and 70 or less is more preferable.

In the embodiment of the present invention, the resin temperature immediately after ejection of the thermoplastic resin composition is a value measured with an infrared radiation thermometer. The resin temperature immediately after ejection of the thermoplastic resin composition is preferably 180 ° C. or higher, more preferably 185 ° C. or higher, further preferably 190 ° C. or higher, particularly preferably 195 ° C. or higher, and most preferably 200 ° C. or higher. The resin temperature immediately after ejection of the thermoplastic resin composition is preferably 260 ° C. or less, more preferably 255 ° C. or less, further preferably 250 ° C. or less, particularly preferably 245 ° C. or less, and most preferably 240 ° C. or less. The infrared radiation thermometer is a thermometer that measures the temperature of an object by measuring the intensity of infrared light or visible light emitted from the object, and a commonly used one can be used.

[(A) carboxyl end amount of polylactic acid resin in thermoplastic resin composition]
In the embodiment of the present invention, the carboxyl terminal amount of (A) polylactic acid resin in the thermoplastic resin composition is the carboxyl terminal amount of (A) polylactic acid resin in the thermoplastic resin composition after melt-kneading. . The measurement method is as follows. The resin composition is weighed so that the content of (A) polylactic acid resin in the resin composition is 1 g, dissolved in 50 mL of a mixture of o-cresol: chloroform = 2: 1, 0.05 mol This is a method of titration with / L ethanolic potassium hydroxide.

In the embodiment of the present invention, the carboxyl terminal amount of the (A) polylactic acid resin in the thermoplastic resin composition is 10 eq / t or more, more preferably 15 eq / t or more, and further preferably 20 eq / t or more. Further, the carboxyl terminal amount of the (A) polylactic acid resin in the thermoplastic resin composition is 100 eq / t or less, more preferably 80 eq / t or less, further preferably 60 eq / t or less, and particularly preferably 40 eq / t or less. preferable. When the carboxyl terminal amount is less than 10 eq / t, there is a problem inferior in biodegradability, and when it exceeds 100 eq / t, the reaction between the carboxyl terminal of (A) polylactic acid resin and the hydroxyl terminal of (B) cellulose fiber occurs. Since it is inadequate, there exists a subject that the deterioration of a mechanical characteristic, coloring, and deterioration of an odor occur.

In the method in which the carboxyl terminal amount of the (A) polylactic acid resin in the thermoplastic resin composition is 10 eq / t to 100 eq / t, (A) the residual catalyst amount of the polylactic acid resin, (A) before melt kneading There is a method of controlling the carboxyl end amount of the polylactic acid resin, (B) the type of cellulose fiber, the blending amount, and the like. Preferably, (i) (A) a polylactic acid resin having a carboxyl terminal amount in the range of 5 eq / t to 50 eq / t and a residual catalyst amount in the range of 1 ppm to 500 ppm is used. (Ii) using a screw having a diameter in the range of 0.1 μm to 15 μm and an average fiber length in the range of 200 μm to 800 μm. It supplies from a feeder, (B) Cellulose fiber is supplied from a side feeder, and it melt-kneads. By doing in this way, the carboxyl terminal of (A) polylactic acid resin and the hydroxyl terminal of (B) cellulose fiber react moderately, and the carboxyl terminal amount of (A) polylactic acid resin in a resin composition is 10 eq / t-100 eq / t, not only excellent mechanical properties such as strength but also (A) the biodegradation rate can be made faster than that of the polylactic acid resin alone, and further, coloring and odor can be suppressed.

[Molded products and applications]
The resin composition of the embodiment of the present invention can be formed into a molded product by a known molding method. As the molding method, injection molding, extrusion molding, press molding, blow molding and the like are preferable. By processing into various molded products such as injection molded products, extrusion molded products, press molded products, and blow molded products, it can be used effectively. The molded product can be used as a sheet, a film, a fiber, or the like.

In the embodiment of the present invention, when injection molding is selected as the molding method, the mold temperature is preferably 30 ° C. or higher, more preferably 50 ° C. or higher, and further preferably 70 ° C. or higher from the viewpoint of moldability and heat resistance. 160 ° C. or lower, preferably 130 ° C. or lower, more preferably 110 ° C. or lower.

Molded articles formed from the resin composition of the embodiment of the present invention include automobile parts (interior / exterior parts, etc.), electrical / electronic parts (various housings, gears, gears, etc.), building members, civil engineering members, agricultural materials, It can be used for various purposes such as daily necessities. Specifically, the molded product is an air flow meter, an air pump, a thermostat housing, an engine mount, an ignition hobbin, an ignition case, a clutch bobbin, a sensor housing, an idle speed control valve, a vacuum switching valve, an ECU housing, a vacuum pump case, an inhibitor switch. , Rotation sensor, acceleration sensor, distributor cap, coil base, actuator case for ABS, top and bottom of radiator tank, cooling fan, fan shroud, engine cover, cylinder head cover, oil cap, oil pan, oil filter, fuel cap, Fuel strainer, distributor cap, vapor canister Automotive underhood parts such as uzing, air cleaner housing, timing belt cover, brake booster parts, various cases, various tubes, various tanks, various hoses, various clips, various valves, various pipes, torque control lever, safety belt parts, Car interior parts such as register blade, washer lever, window regulator handle, window regulator handle knob, passing light lever, sun visor bracket, various motor housings, spare tire cover, door trim, roof rail, fender, garnish, bumper, door mirror stay , Spoiler, hood louver, wheel cover, wheel cap, grill apron cover frame, lamp reflector, Pubezeru, automotive exterior parts such as door handles, wire harness connector, mention may be made of SMJ connector, PCB connector, auto parts represented in the automotive connector, such as door grommet connector. Molded products include notebook computer housings and internal parts, CRT display housings and internal parts, printer housings and internal parts, mobile terminal housings and internal parts such as mobile phones, mobile personal computers, and handheld mobiles, and recording media (CDs, DVDs). , PD, FDD, etc.) drive housings and internal parts, copier housings and internal parts, facsimile housings and internal parts, parabolic antennas, and other electric / electronic parts. In addition, molded products include VTR parts, TV parts, irons, hair dryers, rice cooker parts, microwave oven parts, acoustic parts, video cameras, audio equipment parts such as audio / laser discs (registered trademark) / compact discs, and lighting parts. Home and office electrical product parts represented by refrigerator parts, air conditioner parts, typewriter parts, word processor parts, and the like. Molded products include housings and internal parts for electronic musical instruments, home game machines, portable game machines, various gears, various cases, sensors, LEP lamps, connectors, sockets, resistors, relay cases, motor cases, switches , Capacitors, variable capacitor cases, optical pickups, oscillators, various terminal boards, transformers, plugs, printed wiring boards, tuners, speakers, microphones, headphones, small motors, magnetic head bases, power modules, semiconductors, liquid crystals, FDD carriages, Electric / electronic parts such as FDD chassis, motor brush holder, transformer member, coil bobbin, sash door, blind curtain parts, piping joint, curtain liner, blind parts, gas meter parts, water meter parts, water heater parts, Roof panels, insulation walls, adjusters, plastic bundles, ceiling fishing gear, stairs, doors, floors and other building components, fishing line, fishing nets, seaweed aquaculture nets, fishing bait bags and other marine products, vegetation nets, vegetation mats, grass bags , Grass protection net, curing sheet, slope protection sheet, fly ash holding sheet, drain sheet, water retention sheet, sludge / sludge dewatering bag, concrete formwork, shale gas drilling application (thinning agent, pH adjuster, prevention of mud loss) Civil engineering-related parts such as agents, drilling tools, etc., gears, screws, springs, bearings, levers, key stems, cams, ratchets, rollers, water supply parts, toy parts, fans, tegs, pipes, cleaning jigs, motor parts, Mechanical parts such as microscopes, binoculars, cameras, watches, multi-films, tunnel films, bird protection sheets, vegetation protection nonwoven fabrics, seedling pots, vegetation piles, seed strings Loops, germination sheets, house lining sheets, agricultural PVC film stoppers, slow-release fertilizers, root-proof sheets, horticultural nets, insect nets, juvenile tree nets, printed laminates, fertilizer bags, sample bags, sandbags, Agricultural materials such as animal protection nets, incentive straps, windproof nets, sanitary products such as disposable diapers, sanitary wrapping materials, cotton swabs, towels, and toilet seat wipes, medical non-woven fabrics (stitching reinforcements, adhesion prevention films, prosthetic repair materials ), Wound dressings, wound tape bandages, sticker base fabrics, surgical sutures, fracture reinforcements, medical films and other medical supplies, calendars, stationery, clothing, food packaging films, trays, blisters, knives , Forks, spoons, tubes, plastic cans, pouches, containers, tanks, baskets and other containers, tableware, hot fill containers, microwave cooking containers, cosmetic containers, racks , Foam buffer, paper lami, shampoo bottle, beverage bottle, cup, candy packaging, shrink label, lid material, window envelope, fruit basket, hand tape, easy peel packaging, egg pack, HDD packaging, compost Bags, recording media packaging, shopping bags, containers and packaging such as wrapping films for electrical and electronic parts, natural fiber composites, polo shirts, T-shirts, inners, uniforms, sweaters, socks, ties, and other clothing, curtains, and chairs Ground, carpet, table cloth, cloth mat, wallpaper, furoshiki interior goods, carrier tape, print lamination, thermal stencil printing film, release film, porous film, container bag, credit card, cash card, ID card, IC card, paper, leather, non-woven fabric Hot melt binder, magnetic material, zinc sulfide, electrode binder such as powder, optical element, conductive embossed tape, IC tray, golf tee, garbage bag, plastic bag, various nets, toothbrush, stationery, drainer net, body Towel, hand towel, tea pack, drainage filter, clear file, coat agent, adhesive, bag, chair, table, cooler box, kumade, hose reel, planter, hose nozzle, dining table, desk surface, furniture panel, kitchen It is useful as a cabinet, pen cap, gas lighter, etc.

[Biodegradability evaluation]
The method for evaluating the biodegradability of the thermoplastic resin composition according to the embodiment of the present invention is a method defined in JIS K6953, and is controlled at 58 ° C. as a seeding source of Yawata Bussan Co., Ltd. In this method, a biodegradability test is performed under composting conditions using the number “YK-3”, and the degree of biodegradation is calculated from the measured carbon dioxide generation amount.

A 100 μm-thick press film formed with the thermoplastic resin composition of the embodiment of the present invention was weighed 10 g of a sample having a 5 mm square size, and the biodegradability measured in the biodegradability test was 30 days. It is preferably 40% or more, more preferably 50% or more, and particularly preferably 60% or more. The upper limit of the degree of biodegradation is 100%.

Hereinafter, embodiments of the present invention will be described by way of examples.

In Examples and Comparative Examples, the following materials were used in the formulations shown in the table, but these do not limit the embodiments of the present invention.

[Reference Example 1]
Tin octylate was added as a catalyst, and ring-opening polymerization of lactide was performed to obtain (A-1) polylactic acid resin having a D-form amount of 1.2%, a weight average molecular weight (converted to PMMA) of 160,000, and a melting point of 170 ° C. . The obtained polylactic acid resin (A-1) was decomposed by heating with nitric acid and sulfuric acid, heated and dissolved with dilute nitric acid, and quantified with a plasma emission analyzer (“CID-AP” manufactured by Nippon Jarrell Ash). As a result, the tin content was 10 ppm. In addition, 1 g of (A-1) polylactic acid resin was sampled, dissolved in 50 mL of a mixture of o-cresol: chloroform = 2: 1, and titrated with 0.05 mol / L ethanolic potassium hydroxide. The amount was 20 eq / t.

[Reference Example 2]
For (A-1) polylactic acid resin, the catalyst was removed by solvent washing to obtain (A-2) polylactic acid resin. The obtained polylactic acid resin (A-2) was decomposed by heating with nitric acid and sulfuric acid, heated and dissolved with dilute nitric acid, and quantified with a plasma emission analyzer (“CID-AP” manufactured by Nippon Jarrell Ash). As a result, the tin content was 0.1 ppm. In addition, 1 g of (A-2) polylactic acid resin was sampled, dissolved in 50 mL of a mixture of o-cresol: chloroform = 2: 1, and titrated with 0.05 mol / L ethanolic potassium hydroxide. The amount was 20 eq / t.

[Reference Example 3]
(A-1) After polymerizing the polylactic acid resin, different amounts of catalyst were additionally added to obtain (A-3) polylactic acid resin and (A-4) polylactic acid resin. The obtained (A-3) polylactic acid resin and (A-4) polylactic acid resin were thermally decomposed with nitric acid and sulfuric acid, heated and dissolved with dilute nitric acid, and plasma emission analyzer (manufactured by Nippon Jarrell Ash Co., Ltd.) When quantified by “CID-AP”), the tin content was 300 ppm and 30,000 ppm. Also, 1 g each of (A-3) polylactic acid resin and (A-4) polylactic acid resin was sampled and dissolved in 50 mL of a mixed solution of o-cresol: chloroform = 2: 1, and 0.05 mol / L ethanolic property was obtained. When titrated with potassium hydroxide, the carboxyl end amounts were all 20 eq / t.

[Reference Example 4]
Tin octylate was added as a catalyst, and ring-opening polymerization of lactide was performed to obtain (A-5) polylactic acid resin having a D-form amount of 1.2%, a weight average molecular weight (converted to PMMA) of 200,000, and a melting point of 165 ° C. . The obtained (A-5) polylactic acid resin was thermally decomposed with nitric acid and sulfuric acid, heated and dissolved with dilute nitric acid, and quantified with a plasma emission analyzer (“CID-AP” manufactured by Nippon Jarrell Ash). As a result, the tin content was 10 ppm. Further, 1 g of (A-5) polylactic acid resin was sampled, dissolved in 50 mL of a mixture of o-cresol: chloroform = 2: 1, and titrated with 0.05 mol / L ethanolic potassium hydroxide. The amount was 15 eq / t.

[Reference Example 5]
Tin octylate was added as a catalyst and ring-opening polymerization of lactide was performed to obtain (A-6) polylactic acid resin having a D-form amount of 1.2%, a weight average molecular weight (converted to PMMA) of 120,000, and a melting point of 170 ° C. . The obtained polylactic acid resin (A-6) was thermally decomposed with nitric acid and sulfuric acid, heated and dissolved with dilute nitric acid, and quantified with a plasma emission analyzer (“CID-AP” manufactured by Nippon Jarrell Ash). As a result, the tin content was 10 ppm. In addition, 1 g of (A-6) polylactic acid resin was sampled, dissolved in 50 mL of a mixture of o-cresol: chloroform = 2: 1, and titrated with 0.05 mol / L ethanolic potassium hydroxide. The amount was 40 eq / t.

[Reference Example 6]
(A-1) After polymerizing the polylactic acid resin, different amounts of polycarbodiimide compounds were added as carboxyl end-capping agents to obtain (A-7) polylactic acid and (A-8) polylactic acid. The obtained (A-7) polylactic acid resin and (A-8) polylactic acid were decomposed by heating with nitric acid and sulfuric acid, and then heated and dissolved with dilute nitric acid. A plasma emission analyzer (“CID” manufactured by Nippon Jarrell Ash, Inc.) -AP ")), the tin content was 0.1 ppm. In addition, 1 g each of (A-7) polylactic acid resin and (A-8) polylactic acid resin was sampled and dissolved in 50 mL of a mixed solution of o-cresol: chloroform = 2: 1, and 0.05 mol / L ethanolic property was obtained. When titrated with potassium hydroxide, the carboxyl end amounts were 0 eq / t and 10 eq / t.

[Reference Example 7]
(A-6) Polylactic acid resin was hydrolyzed in a constant temperature and humidity chamber to obtain (A-9) polylactic acid resin. The obtained polylactic acid resin (A-9) was decomposed by heating with nitric acid and sulfuric acid, heated and dissolved with dilute nitric acid, and quantified with a plasma emission analyzer (“CID-AP” manufactured by Japan Jarrell Ash). As a result, the tin content was 10 ppm. Further, 1 g of (A-9) polylactic acid resin was sampled, dissolved in 50 mL of a mixture of o-cresol: chloroform = 2: 1, and titrated with 0.05 mol / L ethanolic potassium hydroxide. The amount was 60 eq / t.

[Reference Example 8]
(A-1) After polymerizing the polylactic acid resin, a catalyst was additionally added, and then hydrolyzed in a constant temperature and humidity chamber to obtain (A-10) polylactic acid resin. The obtained (A-10) polylactic acid resin was thermally decomposed with nitric acid and sulfuric acid, heated and dissolved with dilute nitric acid, and quantified with a plasma emission analyzer (“CID-AP” manufactured by Nippon Jarrell Ash). As a result, the tin content was 30000 ppm. Further, 1 g of (A-10) polylactic acid resin was sampled, dissolved in 50 mL of a mixture of o-cresol: chloroform = 2: 1, and titrated with 0.05 mol / L ethanolic potassium hydroxide. The amount was 60 eq / t.

(A) Polylactic acid resin (A) The weight average molecular weight of polylactic acid resin was measured by gel permeation chromatography (GPC, “Water Model 510” manufactured by Waters) using hexafluoroisopropanol as a solvent. PMMA) weight average molecular weight.

(A) The amount of the residual metal catalyst in the polylactic acid resin was determined by (A) heat-decomposing the polylactic acid resin with nitric acid and sulfuric acid and then heating and dissolving with dilute nitric acid. AP ").
(A-1) Polylactic acid resin (D-form 1.2%, weight average molecular weight (PMMA conversion) 160,000, melting point 170 ° C., residual catalyst amount: 10 ppm, carboxyl terminal amount: 20 eq / t)
(A-2) Polylactic acid resin (D-form 1.2%, weight average molecular weight (PMMA conversion) 160,000, melting point 170 ° C., residual catalyst amount: 0.1 ppm, carboxyl terminal amount: 20 eq / t)
(A-3) Polylactic acid resin (D-form 1.2%, weight average molecular weight (PMMA conversion) 160,000, melting point 170 ° C., residual catalyst amount: 300 ppm, carboxyl terminal amount: 20 eq / t)
(A-4) Polylactic acid resin (D-form 1.2%, weight average molecular weight (PMMA conversion) 160,000, melting point 170 ° C., residual catalyst amount: 30,000 ppm, carboxyl end amount: 20 eq / t)
(A-5) Polylactic acid resin (D-form 1.2%, weight average molecular weight (PMMA conversion) 200,000, melting point 165 ° C., residual catalyst amount: 10 ppm, carboxyl end amount: 15 eq / t)
(A-6) Polylactic acid resin (D-form 1.2%, weight average molecular weight (PMMA conversion) 120,000, melting point 170 ° C., residual catalyst amount: 10 ppm, carboxyl terminal amount: 40 eq / t)
(A-7) Polylactic acid resin (D-form 1.2%, weight average molecular weight (PMMA conversion) 160,000, melting point 170 ° C., residual catalyst amount: 10 ppm, carboxyl terminal amount: 0 eq / t)
(A-8) Polylactic acid resin (D-form 1.2%, weight average molecular weight (PMMA conversion) 160,000, melting point 170 ° C., residual catalyst amount: 10 ppm, carboxyl terminal amount: 10 eq / t)
(A-9) Polylactic acid resin (D-form 1.2%, weight average molecular weight (PMMA conversion) 90,000, melting point 170 ° C., residual catalyst amount: 10 ppm, carboxyl terminal amount: 60 eq / t)
(A-10) Polylactic acid resin (D-form 1.2%, weight average molecular weight (PMMA conversion) 90,000, melting point 170 ° C., residual catalyst amount: 30000 ppm, carboxyl terminal amount: 60 eq / t)

(B) Cellulose fiber The bulk density of the (B) cellulose fiber is a value measured under a 23 ° C., 50% RH environment using a “powder tester” manufactured by Hosokawa Micron.

(B) The average fiber length of a cellulose fiber is an average fiber length measured using "MorFI Fiber Analyzer" manufactured by Techpap. In addition, (B) the average fiber diameter of the cellulose fibers is determined by measuring using a “Vibrodyn Fiber Analyzer” manufactured by Lenzing Technique Instruments Co., Ltd., and determining the titer. Based on the density, this average titer is converted into a diameter. The fiber diameter.
(B-1) Purified cellulose fiber (B-1-1) Purified cellulose fiber (“Tencel”, bulk density: 135 kg / m ³ , average fiber length: 400 μm, average fiber diameter: 10 μm)
(B-1-2) Purified cellulose fiber (“Tencel”, bulk density: 90 kg / m ³ , average fiber length: 480 μm, average fiber diameter: 10 μm)
(B-1-3) Purified cellulose fiber (“Tencel”, bulk density: 55 kg / m ³ , average fiber length: 490 μm, average fiber diameter: 10 μm)
(B-1-4) Purified cellulose fiber (“Tencel”, bulk density: 40 kg / m ³ , average fiber length: 750 μm, average fiber diameter: 10 μm)
(B-1-5) Purified cellulose fiber (“Tencel”, bulk density: 25 kg / m ³ , average fiber length: 1000 μm, average fiber diameter: 10 μm)
(B-1-6) Purified cellulose fiber (“Tencel”, bulk density: 210 kg / m ³ , average fiber length: 100 μm, average fiber diameter: 10 μm)
(B-1-7) Purified cellulose fiber (“Tencel”, bulk density: 135 kg / m 3, average fiber length: 400 μm, average fiber diameter: 10 μm, crystallinity: 50%)
(B-1-8) Purified cellulose fiber (“Tencel”, bulk density: 135 kg / m 3, average fiber length: 400 μm, average fiber diameter: 10 μm, crystallinity: 30%)
(B-2) Natural cellulose fiber (B-2-1) Natural cellulose fiber (kenaf fiber, average fiber length: 750 μm, average fiber diameter: 20 μm, bulk density: 100 kg / m ³ )
(B-2-2) Natural cellulose fiber (bamboo fiber, average fiber length: 3000 μm, average fiber diameter: 150 μm, bulk density: 10 kg / m ³ )

(C) Acrylic resin (C-1) Acrylic resin (Mitsubrene P-531A, manufactured by Mitsubishi Rayon Co., Ltd., weight average molecular weight: 4.5 million)
(C-2) Acrylic resin (Mitsubrene P-530A, manufactured by Mitsubishi Rayon Co., Ltd., weight average molecular weight: 3.1 million)
(C-3) Acrylic resin (manufactured by Kaneka Corporation, Kane Ace PA-20, weight average molecular weight: 1 million)
(C-4) Acrylic resin (manufactured by Mitsubishi Rayon Co., Ltd., Acrypet VH-001, weight average molecular weight: 100,000)
(C-5) Acrylic resin (Kaneka Corporation, Kane Ace PA-10, weight average molecular weight: 800,000)
(C-6) Acrylic resin (manufactured by Kaneka Corporation, Kane Ace PA-60, weight average molecular weight: 8 million)

(D) Crystal nucleating agent (D-1) Inorganic crystal nucleating agent (D-1-1) Talc (average particle size 4 μm, P-6 made by Nippon Talc)
(D-2) Organic crystal nucleating agent (D-2-1) Zinc phenylphosphonate (Nissan Chemical "Eco Promote")

(E) Plasticizer (E-1) Polyalkylene glycol plasticizer (E-1-1) Polyethylene glycol / polypropylene glycol copolymer (Adeka "Pluronic" F68)
(E-2) Polyvalent carboxylic acid plasticizer (E-2-1) Adipic acid benzylmethyl diglycol ester ("Daifatty" -101, manufactured by Daihachi Chemical Industry)

The measurement method and determination method used in the embodiment of the present invention are shown below.

(1) Extrusion processability (strand state)
As shown in Tables 1 to 8, the raw materials were blended and melt kneaded using a 30 mm diameter, L / D = 45 twin screw extruder (TEX-30α manufactured by Nippon Steel) at a cylinder setting temperature of 190 ° C. went. (A) Polylactic acid resin, as required (C) Acrylic resin, (D) Crystal nucleating agent, (E) Plasticizer is supplied from the main feeder of the extruder, and (B) Cellulose fiber is supplied from the side feeder. Supplied. A melted thermoplastic resin composition strand was drawn from the extruder discharge port, and the strand state was evaluated in three stages according to the following criteria, and used as an index of extrusion processability. The more the strands are not fuzzed and the more the strands are not cut, the better the extrusion processability is.
A: No strand fuzz / no strand break B: Strand fuzz present / no strand cut C: Strand fuzz present / strand cut present

(2) Extrusion processability (Discharge port meander state)
In the same manner as in the above item (1), melt kneading was carried out, and the state of the mean at the discharge port of the extruder was evaluated in three stages according to the following criteria, and used as an index for extrusion processability. “Meani” as used herein refers to a material in which a deteriorated resin, a part of an additive, an oxide / decomposed product thereof, or the like adheres to the air release surface of the strand discharge port. The extruding processability is more excellent as the discharge port has no mean.
A: No discharge port mean B: Exhaust port somewhat present C: Discharge port mean considerably present.

(3) (A) Carboxyl terminal amount of polylactic acid resin in thermoplastic resin composition Weigh resin composition so that (A) polylactic acid resin content in the obtained thermoplastic resin composition is 1 g, The solution dissolved in 50 mL of a mixture of o-cresol: chloroform = 2: 1 was titrated with 0.05 mol / L ethanolic potassium hydroxide.

(4) Surface smoothness of extruded product (maximum height of surface roughness)
In the same manner as in the above item (1), melt kneading is carried out, and the strand discharged from the discharge port is cooled by a cooling bath containing water to obtain an extruded strand having a diameter of 3 mm and a length of 10 mm as an extruded product. It was. Using a surface roughness measuring machine “SV-2100” manufactured by Mitutoyo Co., Ltd., the surface of the extruded strand is 5 mm in accordance with JIS B 0601 (1994), and the cutoff value (λc) is 0.8 mm. Height (Ry) was measured. The smaller the value of the maximum height (Ry), the better the surface smoothness of the extruded product.

(5) Injection moldability (molding cycle time)
The obtained thermoplastic resin composition was injection molded at a cylinder temperature of 190 ° C. and a mold temperature of 90 ° C. using an injection molding machine (SG75H-MIV manufactured by Sumitomo Heavy Industries) to obtain a 3.2 mm thick molded product. It was. The shortest time for obtaining a solidified molded product without deformation was measured as the molding cycle time. The shorter the molding cycle time, the better the injection moldability.

(6) Injection molded product surface appearance The obtained thermoplastic resin composition was injection molded at a cylinder temperature of 190 ° C. and a mold temperature of 90 ° C. using an injection molding machine (SG75H-MIV manufactured by Sumitomo Heavy Industries, Ltd.) A molded product with a thickness of 3.2 mm was obtained. By visually observing the surface appearance of the molded product, it was classified as follows. The surface appearance is better as the cellulose fiber is not raised.
A: Cellulose fiber is not raised B: Cellulose fiber is slightly raised C: Cellulose fiber is raised slightly

(7) Heat resistance (deflection temperature under load)
In accordance with ASTM D648, the deflection temperature under load (load 1.82 MPa) of a molded product having a thickness of 3.2 mm was measured. The higher the deflection temperature under load, the better the heat resistance.

(8) Rigidity (flexural modulus)
According to ASTM D638, the flexural modulus of a molded product having a thickness of 3.2 mm was measured. The higher the flexural modulus, the better the rigidity.

(9) Impact resistance (Izod impact strength)
In accordance with ASTM D256, the Izod impact strength of the 3.2 mm thick notched molded product was measured.

(10) Biodegradability After preparing a 100 μm thick press film of the obtained thermoplastic resin composition, 10 g of a sample having a 5 mm square size was weighed and seeded according to JIS K6953. The biodegradability test was conducted under the condition of 58 ° C. in compost using the planting source number “YK-3” of Yawata Bussan Co., Ltd. The biodegradation degree was calculated from the amount of carbon dioxide generated after 30 days, and the biodegradation degree was evaluated in three stages according to the following criteria. The higher the degree of biodegradation, the better the biodegradability.
A: 60% or more, B: 40% or more, less than 60%, C: less than 40%.

(11) Odor 10 g of the obtained thermoplastic resin composition was heated in a glass flask at 100 ° C. for 1 h, and then the odor was confirmed and evaluated in four stages according to the following criteria.
AA: It does not smell, A: It smells slightly, B: It smells a little, C: It smells considerably.

(12) Coloring The coloring of a 3.2 mm thick molded product obtained by molding the obtained thermoplastic resin composition was visually observed and evaluated in four stages according to the following criteria.
AA: white, A: yellow, B: slightly brown, C: brown.

[Examples 1 to 3, 6 to 29, Comparative Examples 1 to 10]
As shown in Tables 1 to 8, the raw materials were blended and melt kneaded using a 30 mm diameter, L / D = 45 twin screw extruder (TEX-30α manufactured by Nippon Steel) at a cylinder setting temperature of 190 ° C. went. (A) Polylactic acid resin, (C) Acrylic resin, (D) Crystal nucleating agent, (E) Plasticizer are supplied from the main feeder of the extruder, and (B) Cellulose fiber is an extruder. A heavy-weight material feeder with an agitator was supplied from a side feeder installed at a position of 40% of the barrel total length, with the uppermost stream of the barrel total length being 0% and the most downstream being 100%. A melted thermoplastic resin composition strand was drawn from the discharge port of the extruder, and a pellet-shaped thermoplastic resin composition was obtained by a strand cutter. The obtained thermoplastic resin composition was injection molded at a cylinder temperature of 190 ° C. and a mold temperature of 90 ° C. using an injection molding machine (SG75H-MIV manufactured by Sumitomo Heavy Industries, Ltd.) to obtain a molded product for evaluation. . Tables 1 to 8 show the results of various evaluations using the obtained molded products.

[Example 4]
Evaluation was carried out in the same manner as in Example 1 except that the position of the side feeder was changed to 80% of the total length of the barrel with the most upstream of the total length of the barrel of the extruder being 0% and the most downstream of 100%.

[Example 5]
Evaluation was carried out in the same manner as in Example 1 except that the installation position of the side feeder was changed to 20% of the total barrel length.

From the results of Tables 1 to 8, it is a thermoplastic resin composition formed by blending 1 to 100 parts by weight of (B) cellulose fiber to 100 parts by weight of (A) polylactic acid resin. (A) the amount of carboxyl terminals of the polylactic acid resin in the composition is in the range of 10 eq / t to 100 eq / t, and (B) the average fiber diameter of the cellulose fibers is in the range of 0.1 μm to 15 μm, and the average In Examples 1 to 29 in which the fiber length is in the range of 200 μm to 800 μm, the extrusion processability and injection moldability are excellent, and the surface smoothness of the molded product is excellent, as compared with Comparative Examples 1 to 10 outside the range. In addition, it can be seen that biodegradability, rigidity, impact resistance, and heat resistance are balanced and excellent, and further, coloring and odor are reduced.

More specifically, from the comparison of Examples 1 to 10 and Comparative Examples 1 to 7, a specific amount of cellulose fiber having a specific average fiber diameter and average fiber length is blended to obtain extrusion processability and injection moldability. In addition, the surface smoothness of the molded product is excellent, biodegradability, rigidity, impact resistance, and heat resistance are balanced and excellent, and coloring and odor are reduced. Further, from the comparison of Examples 1 to 10 and Comparative Examples 8 to 10, by controlling the carboxyl terminal amount of (A) polylactic acid resin in the thermoplastic resin composition within a specific range, extrusion processability, It can be seen that the injection moldability is excellent, the surface smoothness of the molded article is excellent, the biodegradability, rigidity, impact resistance, and heat resistance are balanced and excellent, and coloring and odor are reduced.

Further, from Examples 11 to 16, (A) the residual catalyst amount of the polylactic acid resin is within the range of 1 ppm to 500 ppm, so that the balance of biodegradability, mechanical properties such as bending elastic modulus and impact strength is achieved. It can be seen that coloration and odor are excellent.

Further, from Examples 17 to 26, by blending a specific amount of (C) acrylic resin having a specific weight average molecular weight, the extrusion processability and injection moldability are further improved, and the surface smoothness of the molded product is excellent. In addition, the biodegradability, rigidity, impact resistance, and heat resistance are balanced and excellent.

Further, from Examples 27 to 30, by further blending a crystal nucleating agent and a plasticizer, the extrusion processability and injection moldability are further improved, the surface smoothness of the molded product is excellent, and the biodegradability, rigidity, It can be seen that the impact resistance and heat resistance are balanced and excellent.

From Examples 27 to 28, by blending a specific amount of the (C) acrylic resin, the extrusion processability and injection moldability are further improved, the surface smoothness of the molded product is excellent, and the biodegradability, rigidity, resistance It can be seen that the impact and heat resistance are balanced and excellent.

Claims

(A) A thermoplastic resin composition obtained by blending 1 to 100 parts by weight of cellulose fiber with respect to 100 parts by weight of a polylactic acid resin, wherein (A) the polylactic acid resin in the thermoplastic resin composition The amount of carboxyl ends of the fiber is within the range of 10 eq / t to 100 eq / t, the average fiber diameter of the (B) cellulose fiber is within the range of 0.1 μm to 15 μm, and the average fiber length is within the range of 200 μm to 800 μm. A thermoplastic resin composition.
The thermoplastic resin composition according to claim 1, wherein the amount of residual metal catalyst contained in (A) the polylactic acid resin is in the range of 1 ppm to 500 ppm.
3. The thermoplastic resin composition according to claim 1, wherein the maximum height (Ry) of the surface roughness of an extruded product made of the thermoplastic resin composition is 600 μm or less. Composition.
The thermoplastic resin composition according to any one of claims 1 to 3, wherein the weight average molecular weight is 1 million to 7.5 million with respect to 100 parts by weight of (A) polylactic acid resin. (C) A thermoplastic resin composition comprising 0.1 to 20 parts by weight of an acrylic resin.
The thermoplastic resin composition according to any one of claims 1 to 4, wherein the bulk density of the (B) cellulose fiber before blending is in the range of 30 kg / m 3 to 200 kg / m 3 . A thermoplastic resin composition.
6. The thermoplastic resin composition according to claim 1, further comprising (D) a crystal nucleating agent in an amount of 0.1 to 100 parts by weight per 100 parts by weight of the (A) polylactic acid resin. A thermoplastic resin composition comprising 20 parts by weight.
The thermoplastic resin composition according to any one of claims 1 to 6, further comprising 1 to 20 parts by weight of (E) plasticizer with respect to 100 parts by weight of (A) polylactic acid resin. A thermoplastic resin composition obtained by blending.
A molded article comprising the thermoplastic resin composition according to any one of claims 1 to 7.