Cellulose resin composition and molded body using same

Abstract

Provided is a cellulose resin composition in which bleeding of a plasticizer is suppressed and with which it is possible to form a molded body having excellent properties. A cellulose resin composition containing component A: cellulose acetate, component B: a plasticizer that is a phosphoric acid ester, and component C: a polyester, the component B content being 15-35 mass% relative to a total of 100 mass% of component A, component B, and component C, and the component C content being 0.5-15 mass% relative to a total of 100 mass% of component A, component B, and component C.

Description

Cellulose-based resin composition and molded article using the same

[0001] The present invention relates to a cellulose acetate resin composition made from non-edible cellulose, and a molded article using the same.

[0002] Bioplastics, made from renewable organic resources such as plants, can contribute to combating oil depletion and global warming, and so are beginning to be used in durable products such as electronic devices and automobiles, in addition to general products such as packaging, containers, and textiles. In particular, concerns about future food shortages have led to a demand for the development of new bioplastics made from non-edible plant resources.

[0003] Cellulose acetate is a biomass material obtained by esterifying the hydroxyl groups of cellulose derived from non-edible plant resources such as wood fiber and cotton with acetic acid. Generally, cellulose acetate-based resin compositions are imparted with thermoplasticity by adding a plasticizer. Patent Document 1 uses polyethylene glycol and trimethylolpropane tribenzoate, Patent Document 2 uses polycaprolactone, Patent Document 3 uses polyethylene adipate diol, and Patent Document 4 uses a citrate triester of an alkoxy ether alcohol as the plasticizer.

[0004] International Publication No. 2007-108243 JP 2002-293986 A JP 2000-080202 A JP 10-506128 A

[0005] However, when a plasticizer is blended into a cellulose-based resin composition, the plasticizer may bleed out from a molded article formed using the composition. Furthermore, in recent years, with the diversification of design needs, there has been a demand for resin molded articles having good physical properties in terms of transparency, mechanical strength, flame retardancy, etc. In view of the above-mentioned problems, an object of the present invention is to provide a cellulose-based resin composition that suppresses the bleed out of the plasticizer and can form a molded article having good physical properties.

[0006] In order to achieve the above object, the resin composition of the present invention is a cellulose-based resin composition comprising: Component A: cellulose acetate; Component B: a plasticizer which is a phosphate ester; and Component C: a polyester, wherein the content of Component B is 15 to 35% by mass relative to 100% by mass of the total content of Components A, B, and C, and the content of Component C is 0.5 to 15% by mass relative to 100% by mass of the total content of Components A, B, and C.

[0007] According to the present invention, it is possible to provide a cellulose resin composition that can form a molded article having high transparency and suppressed exudation of plasticizer.

[0008] [Resin composition] The resin composition of the present invention is a cellulose-based resin composition comprising: Component A: cellulose acetate; Component B: a plasticizer which is a phosphate ester; and Component C: a polyester, wherein the content of Component B is 15 to 35% by mass relative to 100% by mass of the total content of Components A, B, and C, and the content of Component C is 0.5 to 15% by mass relative to 100% by mass of the total content of Components A, B, and C.

[0009] <Component A: Cellulose Acetate> The resin composition of the present invention contains cellulose acetate as Component A. As the cellulose acetate, one obtained by using cellulose as a raw material and introducing acetyl groups into at least a portion of the hydroxy groups can be used.

[0010] Cellulose is a linear polymer formed by the polymerization of β-D-glucose molecules (β-D-glucopyranose) via β(1→4) glycosidic bonds, as shown in the following formula (1) (where n is a natural number):

[0011]

[0012] Cellulose is a major component of plants and can be obtained by separating other components such as lignin from plants. In addition to those obtained in this way, cotton (e.g., cotton linters) and pulp (e.g., wood pulp) with a high cellulose content can be used either as is or after purification. Regarding the shape, size, and form of cellulose or its derivatives used as raw materials, it is preferable to use cellulose or its derivatives in powder form with an appropriate particle size and shape in terms of reactivity, solid-liquid separation, and handleability. For example, fibrous or powdery materials with a diameter of 1 to 100 μm (preferably 10 to 50 μm) and a length of 10 μm to 100 mm (preferably 100 μm to 10 mm) can be used.

[0013] The degree of polymerization of cellulose, expressed as the glucose polymerization degree (average polymerization degree), is preferably in the range of 50 to 5,000, more preferably 100 to 3,000, and even more preferably 100 to 1,000. If the degree of polymerization is too low, the strength, heat resistance, etc. of the produced resin may be insufficient. Conversely, if the degree of polymerization is too high, the melt viscosity of the produced resin may become too high, causing problems in molding.

[0014] Each glucose unit constituting cellulose has three hydroxy groups. The cellulose acetate of the present invention is obtained by introducing acetyl groups into cellulose using these hydroxy groups. By introducing acetyl groups into cellulose, the intermolecular forces (intermolecular bonds) of cellulose can be reduced, thereby improving the plasticity of the resin composition.

[0015] The acetyl group can be introduced by reacting a hydroxy group in cellulose with an acylating agent. The acetyl group corresponds to an organic group introduced in place of the hydrogen atom of the hydroxy group in cellulose. The acylating agent is a compound having at least one functional group capable of reacting with the hydroxy group in cellulose, such as a compound having a carboxyl group, a carboxylic acid halide group, or a carboxylic acid anhydride group. Specific examples include aliphatic monocarboxylic acids, their acid halides, and their acid anhydrides.

[0016] The average number of acetyl groups introduced per glucose unit of cellulose (DSＡＣ ) (acetyl group introduction ratio), i.e., the average number of hydroxy groups substituted with acetyl groups per glucose unit (hydroxy group substitution degree), can be set in the range of 0.1 to 3.0. In order to fully obtain the effect of introducing acetyl groups, particularly from the viewpoints of water resistance, flowability, etc., DS ＡＣ is preferably 2.0 or more, more preferably 2.2 or more, and even more preferably 2.4 or more. From the viewpoint of obtaining the effect of introducing an acetyl group while fully obtaining the effect of other groups (hydroxyl group, etc.), DS ＡＣ is preferably 2.9 or less, more preferably 2.8 or less.

[0017] The greater the residual amount of hydroxy groups, the greater the maximum strength and heat resistance of the resin composition, but the greater the water absorption. On the other hand, the greater the conversion rate (degree of substitution) of hydroxy groups, the lower the water absorption and the greater the plasticity and breaking strain, but the lower the maximum strength and heat resistance. Taking these trends into consideration, the conversion rate of hydroxy groups can be appropriately set.

[0018] The average number of remaining hydroxy groups per glucose unit of cellulose acetate (hydroxy group residual degree) can be set in the range of 0 to 2.9. Hydroxy groups may remain from the viewpoint of the maximum strength and heat resistance of the resin composition, for example, the hydroxy group residual degree may be 0.01 or more, and even 0.1 or more. In particular, from the viewpoint of the fluidity of the resin composition, the hydroxy group residual degree of the final cellulose acetate product is preferably 1.0 or less, more preferably 0.8 or less, and particularly preferably 0.6 or less. Furthermore, from the viewpoint of the fluidity of the resin composition as well as water resistance and impact resistance, the hydroxy group residual degree is preferably 0.6 or less, more preferably 0.5 or less, even more preferably 0.4 or less, and particularly preferably 0.2 or less.

[0019] The molecular weight of cellulose acetate is preferably in the range of 10,000 to 400,000 in terms of weight average molecular weight, more preferably in the range of 50,000 to 350,000, even more preferably in the range of 100,000 to 300,000, and even more preferably in the range of 150,000 to 250,000. If the molecular weight is too large, the fluidity of the resin composition may be reduced, making processing difficult and making uniform mixing difficult. Conversely, if the molecular weight is too small, the physical properties of the resin composition, such as impact resistance, may be reduced. This weight average molecular weight can be determined by gel permeation chromatography (GPC) (commercially available standard polystyrene can be used as the standard sample).

[0020] In the resin composition of the present invention, the content of Component A is not particularly limited, but is preferably 50% by mass or more, more preferably 60% by mass or more, and particularly preferably 65% ​​by mass or more, relative to 100% by mass of the total content of Components A, B, and C. Furthermore, it is preferably 85% by mass or less, more preferably 80% by mass or less, and particularly preferably 78% by mass or less, relative to 100% by mass of the total content of Components A, B, and C.

[0021] <Component B: Plasticizer> The resin composition of the present invention contains a phosphate ester plasticizer as Component B. Component B may be used singly or in combination of two or more. Component B functions as a flame retardant and plasticizer, and can impart flame retardancy and processing stability to the resin composition. Examples of Component B include, but are not limited to, one or more phosphate esters selected from the group consisting of triphenyl phosphate, triethyl phosphate, tributyl phosphate, tricresyl phosphate, cresyl di-2,6-xylenyl phosphate, and compounds represented by the following formula (2):

[0022]

[0023] In the above formula (2), n is an integer of 1 or more, preferably 1 to 3, and more preferably n = 1. By using these predetermined phosphate esters, a resin composition with high impact strength can be formed.

[0024] The plasticizer is more preferably triphenyl phosphate. Triphenyl phosphate is less volatile and has high compatibility with Component A. Furthermore, the use of triphenyl phosphate allows the formation of a resin composition with high mechanical strength.

[0025] In the resin composition of the present invention, the content of Component B is preferably 15% by mass or more, more preferably 19% by mass or more, and particularly preferably 20% by mass or more, relative to 100% by mass of the total content of Components A, B, and C. Furthermore, the content of Component B is preferably 35% by mass or less, more preferably 30% by mass or less, and particularly preferably 25% by mass or less, relative to 100% by mass of the total content of Components A, B, and C. When the content of Component B is within this range, the resin composition can be used to obtain a molded article that has excellent impact strength and suppresses bleeding (bleed-out). If the content of Component B is too high, the plasticizer may bleed out from the molded article, and if the content of Component B is too low, the impact strength of the molded article may be insufficient.

[0026] The resin composition of the present invention may contain, in addition to the phosphoric acid ester plasticizer, other plasticizers within the scope of not impairing the effects of the present invention. Examples of other plasticizers include phthalate esters such as dibutyl phthalate, diaryl phthalate, diethyl phthalate, dimethyl phthalate, di-2-methoxyethyl phthalate, ethylphthalyl-ethyl glycolate, and methylphthalyl-ethyl glycolate; tartaric acid esters such as dibutyl tartrate; adipic acid esters such as dioctyl adipate and diisononyl adipate; polyhydric alcohol esters such as triacetin, diacetylglycerin, tripropionitrile glycerin, and glycerin monostearate; dibutyl adipate, dioctyl adipate, dibutyl azelate, and dioctyl azelate. Examples of suitable plasticizers include aliphatic dicarboxylic acid dialkyl esters such as ethyl citrate and dioctyl sebacate; citric acid esters such as triethyl citrate, acetyl triethyl citrate, and acetyl tributyl citrate; epoxidized vegetable oils such as epoxidized soybean oil and epoxidized linseed oil; castor oil and its derivatives; benzoic acid esters such as ethyl O-benzoylbenzoate; aliphatic dicarboxylic acid esters such as sebacic acid esters and azelaic acid esters; unsaturated dicarboxylic acid esters such as maleic acid esters; and others such as N-ethyltoluenesulfonamide, O-cresyl p-toluenesulfonate, and tripropionin. The amount of the other plasticizer is, for example, 20% by mass or less, preferably 10% by mass or less, and more preferably 5% by mass or less of the phosphate ester plasticizer. It is also preferable that the other plasticizer is not used at all.

[0027] <Component C: Polyester> The resin composition of the present invention contains a polyester as component C. Component C may be used singly or in combination of two or more. In the present invention, "polyester" refers to a polycondensate synthesized by polymerizing a carboxylic acid and / or an alcohol via an ester bond. Examples of polyester include a polycondensate synthesized by dehydration condensation of a dicarboxylic acid and a diol, and a polycondensate synthesized by dehydration condensation of a hydroxycarboxylic acid. Examples of dicarboxylic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid, and terephthalic acid. Adipic acid or succinic acid is preferred, and succinic acid is particularly preferred. Examples of diols include 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, heptaethylene glycol, and 1,2-benzenedimethanol, with 1,4-butanediol being preferred. Examples of hydroxycarboxylic acids include lactic acid, tartaric acid, citric acid, salicylic acid, gallic acid, and 6-hydroxyhexanoic acid, with lactic acid being preferred. By selecting the appropriate combination of carboxylic acid and alcohol and the appropriate hydroxycarboxylic acid, various polyesters can be synthesized. Preferred polyesters include polybutylene succinate, polybutylene succinate adipate, polylactic acid, and mixtures thereof. Using these specific polyesters can suppress plasticizer leaching and produce resin compositions with excellent physical properties. Furthermore, polybutylene succinate is particularly preferred as a polyester.

[0028] In the resin composition of the present invention, the content of component C is preferably 0.5% by mass or more, more preferably 1.0% by mass or more, and particularly preferably 2.5% by mass or more, relative to 100% by mass of the total content of components A, B, and C. Furthermore, relative to 100% by mass of the total content of components A, B, and C, the content is preferably less than 15% by mass, more preferably 10% by mass or less, and particularly preferably 5% by mass or less. By having the content of component C within this range, it is possible to suppress the exudation (bleed-out) of component B. If the content of component C is too high, processing stability may be impaired, and if the content of component C is too low, the effect of suppressing the exudation of component B may be insufficient.

[0029] Increasing the content of component B can improve mechanical strength (impact resistance), but if the content of component B is high, exudation may occur in a high-temperature, high-humidity environment. Therefore, by adding component C, the content of component B can be increased while suppressing exudation. Therefore, by containing components A, B, and C, the resin composition of the present invention achieves both mechanical strength and suppression of exudation.

[0030] The cellulose-based resin composition according to the present embodiment may contain other components to the extent that the desired appearance and properties are not impaired when the composition is molded. In one aspect, for example, the total amount of components (A), (B), and (C) can be set to the range of 80 to 100% by mass of the entire cellulose-based resin composition, but is preferably 90% by mass or more, more preferably 95% by mass or more, and even more preferably 99% by mass or more.

[0031] In one embodiment, the resin composition of the present invention may contain, as necessary, a metal hydroxide such as aluminum hydroxide, magnesium hydroxide, or calcium hydroxide, taking into consideration maintaining transparency. The resin composition can improve its flame retardancy by containing a metal hydroxide. Among these, aluminum hydroxide is particularly preferred because it has a high heat absorption effect and excellent flame retardancy. The surface of the metal hydroxide may be surface-treated with various organic substances such as epoxy resins and phenolic resins. One type of metal hydroxide may be used alone, or two or more types may be used in combination. From the viewpoint of transparency, the amount of the metal hydroxide is preferably 0.5% by mass or less, more preferably 0.3% by mass or less, and particularly preferably 0.1% by mass or less, based on the total composition.

[0032] Inorganic or organic granular or fibrous fillers can be added to the resin composition of the present invention as needed, taking into consideration maintaining transparency. Adding a filler can further improve strength and rigidity. Examples of fillers include mineral particles (talc, mica, calcined silica earth, kaolin, sericite, bentonite, smectite, clay, silica, quartz powder, glass beads, glass powder, glass flakes, milled fiber, wollastonite (or wollastonite), etc.), boron-containing compounds (boron nitride, boron carbide, titanium boride, etc.), metal carbonates (magnesium carbonate, heavy calcium carbonate, light calcium carbonate, etc.), metal silicates (calcium silicate, aluminum silicate, magnesium silicate, magnesium aluminosilicate, etc.), metal oxides (magnesium oxide, etc.), metal sulfates (calcium sulfate, barium sulfate, etc.), metal carbides (silicon carbide, aluminum carbide, titanium carbide, etc.), metal nitrides (aluminum nitride, silicon nitride, titanium nitride, etc.), white carbon, and various metal foils. Examples of fibrous fillers include organic fibers (natural fibers, paper, etc.), inorganic fibers (glass fibers, asbestos fibers, carbon fibers, silica fibers, silica-alumina fibers, wollastonite, zirconia fibers, potassium titanate fibers, etc.), metal fibers, etc. These fillers can be used alone or in combination of two or more.

[0033] In one aspect of this embodiment, the resin composition may contain glass fibers. The inclusion of glass fibers in the resin composition improves the strength of the molded body. The glass fibers are not particularly limited, but the fiber length of the glass fibers before melt-kneading is preferably 0.5 mm or more, and preferably 30 mm or less, more preferably 10 mm or less. The cross-sectional shape of the glass fibers is not particularly limited, and examples include circular, elliptical, oblong, and non-circular. The fiber diameter of the glass fibers, calculated as the cross-sectional area of ​​a perfect circle, may be, for example, 3 to 20 μm. In one aspect of this embodiment, the content of the glass fibers relative to the total mass of the resin composition may be 0% by mass, but is, for example, preferably 0.5% by mass or more, more preferably 1% by mass or more, and even more preferably 3% by mass or more, and is also preferably 20% by mass or less, more preferably 10% by mass or less, and even more preferably 8% by mass or less.

[0034] In one aspect of this embodiment, the resin composition may contain a hydrolysis inhibitor. The hydrolysis inhibitor refers to a compound that can react with carboxylic acid generated by hydrolysis of cellulose acetate or polyester. By including the hydrolysis inhibitor in the resin composition, the durability and other properties of the molded article can be improved.

[0035] Examples of the hydrolysis inhibitor include compounds having a functional group such as a carbodiimide group, an epoxy group, or an oxazoline group, and carbodiimide compounds having a carbodiimide group are preferred.

[0036] The carbodiimide compound is a compound having one or more carbodiimide groups (-N=C=N-) in the molecule. The carbodiimide compound may be a compound having two or more carbodiimide groups in the molecule, i.e., a polyvalent carbodiimide compound. In one embodiment, the polyvalent carbodiimide compound preferably has 30 or fewer carbodiimide groups in the carbodiimide compound. Furthermore, as the carbodiimide compound, a high-molecular-weight polycarbodiimide produced by a decarboxylation condensation reaction of a diisocyanate in the presence of a carbodiimidization catalyst may be used.

[0037] Examples of the carbodiimide compound include monocarbodiimides such as aliphatic monocarbodiimides, alicyclic monocarbodiimides, and aromatic monocarbodiimides, and polycarbodiimides such as aliphatic polycarbodiimides, alicyclic polycarbodiimides, and aromatic polycarbodiimides.

[0038] Examples of the aliphatic monocarbodiimide include diisopropylcarbodiimide, dimethylcarbodiimide, diisobutylcarbodiimide, and dioctylcarbodiimide.

[0039] Examples of alicyclic monocarbodiimides include dicyclohexylcarbodiimide.

[0040] Examples of aromatic monocarbodiimides include N,N'-diphenylcarbodiimide and N,N'-di-2,6-diisopropylphenylcarbodiimide.

[0041] Examples of polycarbodiimides include those obtained by subjecting the following diisocyanates to a decarboxylation condensation reaction. Examples of such diisocyanates include 1,4-phenylene diisocyanate, 1,3,5-triisopropyl-phenylene-2,4-diisocyanate, 4,4'-diphenylmethane diisocyanate, 3,3'-dimethoxy-4,4'-diphenylmethane diisocyanate, 3,3'-dimethyl-4,4'-diphenylmethane diisocyanate, 4,4'-diphenylether diisocyanate, 3,3'-dimethyl-4,4'-diphenylether diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1-methoxyphenyl-2,4-diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, and tetramethylxylylene diisocyanate. These can be used alone or in combination of two or more. Such high molecular weight polycarbodiimides may be synthesized or commercially available products may be used.

[0042] The number average molecular weight of the polycarbodiimide is not particularly limited, but is preferably 200 or more, more preferably 300 or more, and preferably 20,000 or less.

[0043] The carbodiimide compound may be either a carbodiimide compound having an isocyanate group in the molecule or a carbodiimide compound not having an isocyanate group in the molecule, and can be appropriately selected. In the case of a polycarbodiimide, both ends of the molecule or any part in the molecule may have a functional group such as an isocyanate group, or the molecular chain may be branched, or the molecular structure may be different from that of other parts. In addition, the carbodiimide compound may have a heterocycle or other functional group in the molecule.

[0044] As the carbodiimide compound, commercially available products may be used, and examples thereof include the Carbodilite (registered trademark) series manufactured by Nisshinbo Chemical Inc. (e.g., Carbodilite HMV-15CA, HMV-5CA-LC, LA-1); STABAXOL I POWDER, STABAXOL P, STABAXOL P 100 manufactured by LANXESS; and TCC-NP manufactured by Teijin Limited.

[0045] Examples of the compound containing an epoxy group include a glycidyl ester compound, a glycidyl ether compound, etc. Examples of the compound containing an oxazoline group include a bisoxazoline compound, etc.

[0046] The hydrolysis inhibitors may be used alone or in combination of two or more.

[0047] The content of the hydrolysis inhibitor is not particularly limited and may be 0% by mass relative to 100% by mass of the total content of Components A, B, and C. However, for example, it is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and is preferably 5% by mass or less, more preferably 3% by mass or less.

[0048] The resin composition may contain, as other components, additives commonly used in ordinary molding resin materials, particularly ordinary cellulose-based resins, within the scope of not impairing the effects of the present invention, such as phenolic or phosphorus-based antioxidants, light stabilizers, ultraviolet absorbers, antistatic agents, antibacterial and antifungal agents, and fillers.

[0049] [Method for Producing Resin Composition] The method for producing the resin composition of the present invention is not particularly limited, and for example, the resin composition can be obtained by melt-mixing component A, component B, and component C, and other components as needed, in a conventional mixer. As the mixer, for example, a compounding device such as a tumbler mixer, ribbon blender, single-screw or multi-screw mixer extruder, kneading kneader, or kneading roll can be used. After melt-mixing, the mixture can be granulated into an appropriate shape as needed, and can be pelletized using, for example, a pelletizer.

[0050] [Molded Article] A molded article formed using the resin composition according to the present invention can be molded into a desired shape by a conventional molding method. The thickness of the molded article is not particularly limited, but from the viewpoint of strength, it is preferably 0.5 mm or more, more preferably 0.8 mm or more. Furthermore, from the viewpoint of flame retardancy, the thickness of the molded article is preferably 1.0 mm or more, more preferably 1.6 mm or more, more preferably 2.0 mm or more, and even more preferably 3.2 mm or more. On the other hand, the upper limit of the thickness of the molded article is not particularly limited and can be appropriately set depending on the required shape, strength, etc., but can be, for example, 10 mm or less, or even 5 mm or less. In the molded article of the present invention, the haze value of a 300 μm thick molded article is preferably 55% or less, more preferably 35% or less, even more preferably 30% or less, and particularly preferably 20% or less.

[0051] The resin composition of the present invention can be molded into a molded article according to the intended use by a conventional molding method such as injection molding, injection compression molding, extrusion molding, or hot press molding.

[0052] The molded article formed using the resin composition according to the present invention can be applied to housings, exteriors, decorative panels, and decorative sheets, and can be used in place of components used in, for example, electronic devices, home appliances, building materials, furniture, and automobiles. For example, it can also be used in housings and exterior parts of electronic devices and home appliances, interior components of building materials, and interior materials of automobiles.

[0053] Applications for electronic devices or home appliances include housings for personal computers, landline phones, mobile phone terminals, smartphones, tablets, POS terminals, routers, projectors, speakers, lighting equipment, copiers, multifunction printers, calculators, remote controls, refrigerators, washing machines, humidifiers, dehumidifiers, video recorder players, vacuum cleaners, air conditioners, rice cookers, electric shavers, electric toothbrushes, dishwashers, broadcasting equipment, clock faces and exteriors, and cases for mobile devices such as smartphones.

[0054] Automotive applications include interior instrument panels, dashboards, cup holders, door trim, armrests, door handles, door locks, steering wheels, brake levers, ventilators, shift levers, and the like.

[0055] The present invention will be described in more detail below with reference to specific examples, but the present invention is not limited to these.

[0056] [Components of Resin Composition] The components used in producing the resin compositions of the examples are shown below. <Component A: Cellulose acetate> Cellulose acetate (manufactured by Daicel Corporation, product name: L-50, acetyl group introduction ratio (degree of substitution) DS = 2.4, acetylation degree: 55%, degree of polymerization based on 6% viscosity: 180) <Component B: Plasticizer> Triphenyl phosphate (manufactured by Daihachi Chemical Industry, product name: TPP) <Component B'> Polyether ester plasticizer (manufactured by ADEKA, product name: RS-1000) <Component C: Polyester> Polybutylene succinate (PBS) (manufactured by PTT MCC Biochem, product name: FZ71PM) Weight average molecular weight: 110,000 (based on standard polystyrene), number average molecular weight = 53,000 (based on standard polystyrene) Polybutylene succinate adipate (PBSA) (manufactured by PTT MCC Biochem, product name: FD92PM) Polylactic acid (PLA) (manufactured by Nature Works, product name: Ingeo Biopolymer 3001D) <Component C'> Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) (manufactured by TianAn Biologic Materials, product name: ENMAT Y1000) Polybutylene adipate terephthalate (PBAT) (manufactured by Jinhui Zhaolong High Technology, product name: Ecoworld PBAT) Polycaprolactone (PCL) (manufactured by Daicel, product name: PLACCEL H1P) <Others> Aluminum hydroxide (manufactured by Nippon Light Metal Co., Ltd., product name: BE023) (average particle size: 2 μm)

[0057] [Production of Molded Articles] The constituent materials were thoroughly mixed by hand mixing at the blending ratios shown in Tables 2 to 5. The units of the values ​​for the blending ratios are mass% relative to the total composition. The resulting mixture was fed into a co-rotating twin-screw extruder (manufactured by STEER, product name: Omega30H [φ30, L / D=60]), kneaded at a blending temperature of 200°C and a rotation speed of 120 rpm, water-cooled, recovered, and pelletized. The resulting pellets were dried again at 80°C for 5 hours immediately before molding, and used to produce molded articles (evaluation samples) of specified dimensions using an injection molding machine (manufactured by Toshiba Machine, product name: EC20P).

[0058] [Evaluation Test] The prepared evaluation samples were subjected to the following evaluations.

[0059] <Transparency (Haze)> The haze of a disk-shaped evaluation sample having a diameter of 50 mm and a thickness of 300 μm was measured using a haze meter (manufactured by Murakami Color Research Laboratory, product name: HM-65W type, in accordance with JIS K 7136). A D65 light source was used.

[0060] <Charpy Impact Test> A Charpy impact test was carried out using an evaluation sample having the shape of JIS K 7162 test piece 1A in accordance with JIS K7111-1 (notched: Type A (notch cutter tip R 0.25 mm)).

[0061] <Exudation test> An evaluation sample in the shape of JIS K 7162 test piece 1A was placed in a constant temperature and humidity chamber at 60°C and 85% RH, and the presence or absence of exudation after 24 hours was evaluated visually. ◯: No exudation or very little exudation was observed △: Slight exudation was observed ×: Exudation was observed

[0062] <Flame Retardancy (UL94V Test)> Evaluation samples, 125 mm long, 13 mm wide, and 2.0 mm thick, were left in a thermostatic chamber at 23°C and 50% humidity for 48 hours, and then tested according to the UL94 test (combustion test for plastic materials for equipment components) established by Underwriters Laboratories. UL94V is a method in which a burner flame (20±1 mm flame) is applied to the bottom of a test specimen of a specified size held vertically for 10 seconds, and flame retardancy is evaluated based on the subsequent burning time and dripping properties. The flame retardancy is classified into grades 5V-A, 5V-B, V-0, V-1, V-2, and HB, in descending order of flame retardancy. V-2 or higher is considered good flame retardancy. The test specimens were evaluated for conformance to the V-2 class shown in Table 1 below. 〇: Conforms ×: Does not conform

[0063]

[0064] The flaming combustion time is the length of time the test specimen continues to burn with a flame after the ignition source (burner) is removed, where t1 is the burning time after the first flame contact, t2 is the burning time after the second flame contact, and t3 is the afterglow (flameless combustion) time after the second flame contact. The second flame contact is performed by immediately applying the burner flame to the test specimen for 10 seconds after the flame has gone out after the first flame contact. The ignition of cotton by dripping is determined by whether or not the cotton marker located 300±10 mm below the bottom end of the test specimen is ignited by dripping from the test specimen.

[0065]

[0066] As shown in Table 2, high transparency was confirmed in Test Examples 1 to 6, which combined a phosphate ester plasticizer (Component B) with specific polyesters (PBS, PBSA, PLA). On the other hand, transparency was impaired in Test Examples 10 to 15, which used a plasticizer other than phosphate ester (Component B'), and Test Examples 7 to 12, which used another polyester (Component C'). Thus, it was confirmed that by combining a specific type of plasticizer with a specific polyester, molded articles with high transparency and good appearance could be obtained.

[0067]

[0068] As shown in Table 3, by using specific polyesters (PBS, PBSA, PLA) (component C) (Test Examples 16 to 18), the amount of plasticizer (component B) can be reduced, and it was confirmed that even when the amount of plasticizer was reduced, the impact strength was actually improved.

[0069]

[0070] As shown in Table 4, in order to suppress exudation of the plasticizer and improve moldability, it was confirmed that the amount of the specific polyester (component C) is preferably 0.5% by mass or more, more preferably 1.0% by mass or more, and is preferably less than 15% by mass, and more preferably 10% by mass or less, relative to 100% by mass of the total content of components A, B, and C. Furthermore, it was confirmed that the amount of the phosphate ester plasticizer (component B) is preferably 15 to 35% by mass, more preferably 30% by mass or less, and particularly preferably 25% by mass or less, relative to 100% by mass of the total content of components A, B, and C.

[0071]

[0072] As shown in Table 5, it was confirmed that by combining a phosphate ester plasticizer (component B) with a specific polyester (component C), a molded product can be obtained that not only has an exudation suppression effect and impact strength, but also flame retardancy.

[0073] Although the present invention has been described above with reference to the embodiments and examples, the present invention is not limited to the above-described embodiments and examples. Various modifications that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention.

[0074] Some or all of the above embodiments can be described as follows, but the disclosure of the present application is not limited to the following supplementary notes.

[0075] (Appendix 1) A cellulose-based resin composition comprising: Component A: cellulose acetate; Component B: a plasticizer which is a phosphate ester; and Component C: a polyester, wherein the content of Component B is 15 to 35% by mass relative to 100% by mass of the total content of Components A, B, and C, and the content of Component C is 0.5 to 15% by mass relative to 100% by mass of the total content of Components A, B, and C. (Appendix 2) The cellulose-based resin composition according to Appendices 1, wherein Component B is at least one selected from the group consisting of triphenyl phosphate, triethyl phosphate, tributyl phosphate, tricresyl phosphate, cresyl di-2,6-xylenyl phosphate, and a compound represented by the following formula (2): (Appendix 3) The cellulose-based resin composition according to Appendices 1 or 2, wherein Component C is at least one selected from the group consisting of polybutylene succinate, polybutylene succinate adipate, and polylactic acid. (Appendix 4) The cellulose-based resin composition according to any of the preceding Appendices, wherein the content of Component B is 19 to 30% by mass relative to 100% by mass of the total content of Components A, B, and C. (Appendix 5) The cellulose-based resin composition according to any of the preceding Appendices, wherein the content of Component C is 1.0 to 10% by mass relative to 100% by mass of the total content of Components A, B, and C. (Appendix 6) The cellulose-based resin composition according to any of the preceding Appendices, wherein the content of Component B is 20 to 25% by mass relative to 100% by mass of the total content of Components A, B, and C. (Appendix 7) The cellulose-based resin composition according to any one of the preceding Appendices, wherein the content of Component C is 2.5 to 5 mass% relative to 100 mass% of the total content of Components A, B, and C. (Appendix 8) The cellulose-based resin composition according to any one of the preceding Appendices, wherein the total amount of Components A, B, and C is in the range of 80 to 100 mass% based on the total cellulose-based resin composition. (Appendix 9) The cellulose-based resin composition according to any one of the preceding Appendices, further comprising a metal hydroxide. (Appendix 10) The cellulose-based resin composition according to Appendice 9, wherein the amount of the metal hydroxide is 0.5 mass% or less based on the total composition. (Appendix 11) The cellulose-based resin composition according to any one of the preceding Appendices, further comprising glass fibers. (Appendix 12) The cellulose-based resin composition according to Appendice 11, wherein the amount of the glass fibers is 0.5 to 10 mass% based on the total composition. (Appendix 13) The cellulose-based resin composition according to any one of the preceding Appendices, further comprising a hydrolysis inhibitor. (Appendix 14) The cellulose-based resin composition according to Appendix 13, wherein the amount of the hydrolysis inhibitor is 0.1 to 5% by mass, relative to 100% by mass of the total content of Components A, B, and C.(Appendix 15) A cellulose-based resin composition comprising: Component A: cellulose acetate; Component B: a plasticizer which is a phosphate ester; and Component C: a polyester, wherein Component B is at least one selected from the group consisting of triphenyl phosphate, triethyl phosphate, tributyl phosphate, tricresyl phosphate, cresyl di-2,6-xylenyl phosphate, and a compound represented by the following formula (2), and Component C is at least one selected from the group consisting of polybutylene succinate, polybutylene succinate adipate, and polylactic acid, wherein the content of Component A is 50 to 85% by mass relative to 100% by mass of the total content of Components A, B, and C, the content of Component B is 15 to 35% by mass relative to 100% by mass of the total content of Components A, B, and C, and the content of Component C is 0.5 to 15% by mass relative to 100% by mass of the total content of Components A, B, and C. (Appendix 16) A molded article formed using the cellulose resin composition according to any one of the preceding appendices. (Appendix 17) The molded article according to appendix 16, wherein the haze value of the molded article when 300 μm thick is 55% or less. (Appendix 18) The molded article according to appendix 16, wherein the haze value of the molded article when 300 μm thick is 35% or less. (Appendix 19) The molded article according to appendix 16, wherein the haze value of the molded article when 300 μm thick is 30% or less. (Appendix 20) The molded article according to appendix 16, wherein the haze value of the molded article when 300 μm thick is 20% or less. (Appendix 21) The molded article according to appendices 16 to 20, which is any one of housings, exterior materials, interior materials, decorative panels, and decorative sheets for electronic devices, home appliances, building materials, furniture, and automobiles. (Appendix 22) The molded article according to Appendix 21, wherein the electronic device or home appliance is any one of a personal computer, a landline telephone, a mobile phone terminal, a smartphone, a tablet, a POS terminal, a router, a projector, a speaker, a lighting fixture, a copier, a multifunction printer, a calculator, a remote control, a refrigerator, a washing machine, a humidifier, a dehumidifier, a video recorder / player, a vacuum cleaner, an air conditioner, a rice cooker, an electric shaver, an electric toothbrush, a dishwasher, broadcasting equipment, and a clock. (Appendix 23) The molded article according to Appendix 21, wherein the electronic device or home appliance is any one of an instrument panel, a dashboard, a cup holder, a door trim, an armrest, a door handle, a door lock, a steering wheel, a brake lever, a ventilator, and a shift lever in an automobile.

Claims

1. Component A: cellulose acetate, and Component B: a plasticizer which is a phosphate ester, and Component C: a polyester, and comprising, the content of the Component B with respect to the total content of 100% by mass of the Component A, the Component B and the Component C being 15 to 35% by mass, and the content of the Component C with respect to the total content of 100% by mass of the Component A, the Component B and the Component C being 0.5 to 15% by mass, a cellulose resin composition.

2. The cellulose resin composition according to claim 1, wherein the Component B is at least one selected from the group consisting of triphenyl phosphate, triethyl phosphate, tributyl phosphate, tricresyl phosphate, cresyl di(2,6-xylyl) phosphate, and a compound represented by the following formula (2). 【Chemical Formula 1】

3. The cellulose resin composition according to claim 1 or 2, wherein the Component C is at least one selected from the group consisting of polybutylene succinate, polybutylene succinate adipate, and polylactic acid.

4. The cellulose resin composition according to claim 1 or 2, wherein the content of the Component B with respect to the total content of 100% by mass of the Component A, the Component B and the Component C is 19 to 30% by mass.

5. The cellulose resin composition according to claim 1 or 2, wherein the content of the Component C with respect to the total content of 100% by mass of the Component A, the Component B and the Component C is 1.0 to 10% by mass.

6. The cellulose resin composition according to claim 1 or 2, further comprising a metal hydroxide.

7. The cellulose resin composition according to claim 1 or 2, further comprising glass fibers.

8. The cellulose resin composition according to claim 1 or 2, further comprising a hydrolysis inhibitor.

9. A molded article formed using the cellulose resin composition according to claim 1 or 2.

10. The molded article according to claim 9, wherein the haze value of the molded article having a thickness of 300 μm is 35% or less.

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