Cellulose resin composition and molded body using same

Abstract

Provided is a cellulose resin composition with which it is possible to form a molded body having excellent flame retardance and mechanical strength as well as suppressed bleed-out of plasticizer. A resin composition containing a component A: cellulose acetate, a component B: a plasticizer that is a phosphoric acid ester, a component C: a polyester, and a component D: a metal hydroxide, wherein the content of the component B is 20-30 mass% relative to the total content of component A, component B, and component C of 100 mass%, the content of the component C is 0.5-10 mass% relative to the total content of component A, component B, and component C of 100 mass%, and the content of the component D is 0.5-20 mass% relative to the composition as a whole.

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 the addition of a plasticizer. For example, Patent Document 1 describes a resin composition composed of cellulose acetate, a plasticizer, and a bleed-out inhibitor.

[0004] On the other hand, in order to apply cellulose acetate-based resin compositions to applications requiring high flame retardancy, such as electronic devices, flame retardancy measures are necessary, and it is known that a flame retardant, particularly a metal hydroxide, is added to the resin composition.

[0005] JP 2007-161943 A

[0006] However, when a large amount of inorganic flame retardant is added to obtain high flame retardancy, toughness may decrease, and it has been difficult to achieve both flame retardancy and mechanical strength. To achieve both, it is effective to increase the blending ratio of phosphate ester, which is a plasticizer and a flame retardant, but adding a large amount of phosphate ester causes the problem of leaching out of the phosphate ester under high temperature and high humidity conditions.

[0007] In view of the above-mentioned problems, an object of the present invention is to provide a cellulose-based resin composition that is excellent in flame retardancy and mechanical strength and can form a molded article in which the exudation of plasticizer is suppressed.

[0008] In order to achieve the above object, the resin composition of the present invention is a resin composition comprising: Component A: cellulose acetate; Component B: a plasticizer which is a phosphate ester; Component C: a polyester; and Component D: a metal hydroxide, wherein the content of Component B is 20 to 30% by mass relative to 100% by mass of the total content of Components A, B, and C; the content of Component C is 0.5 to 10% by mass relative to 100% by mass of the total content of Components A, B, and C; and the content of Component D is 0.5 to 20% by mass relative to the total content of the composition.

[0009] According to the present invention, it is possible to provide a cellulose resin composition that can be used to form a molded article that is excellent in flame retardancy and mechanical strength and in which exudation of plasticizer is suppressed.

[0010] [Resin composition] The resin composition of the present invention is a resin composition comprising: Component A: cellulose acetate; Component B: a plasticizer which is a phosphate ester; Component C: a polyester; and Component D: a metal hydroxide, wherein the content of Component B is 20 to 30% by mass relative to 100% by mass of the total content of Components A, B, and C; the content of Component C is 0.5 to 10% by mass relative to 100% by mass of the total content of Components A, B, and C; and the content of Component D is 0.5 to 20% by mass relative to the total content of the composition.

[0011] <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.

[0012] 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):

[0013]

[0014] 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.

[0015] 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.

[0016] 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.

[0017] 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.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] 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).

[0022] In the resin composition of the present invention, the content of Component A is not particularly limited, but is preferably 45% by mass or more, more preferably 50% by mass or more, and particularly preferably 55% by mass or more, relative to 100% by mass of the total content of Components A, B, and C. Furthermore, the content of Component A is preferably 80% by mass or less, more preferably 78% by mass or less, and particularly preferably 75% by mass or less, relative to 100% by mass of the total content of Components A, B, and C.

[0023] <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 both a plasticizer and a flame retardant, and can impart processing stability and flame retardancy 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):

[0024]

[0025] 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.

[0026] In one embodiment of the present invention, from the viewpoint of flame retardancy and high compatibility with cellulose acetate, triphenyl phosphate is more preferably used as Component B. Triphenyl phosphate is less volatile and has high compatibility with Component A.

[0027] In the resin composition of the present invention, the content of component B is preferably 20% by mass or more, more preferably 22% by mass or more, and more preferably 25% 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 30% by mass or less, more preferably 29% by mass or less, and more preferably 28% 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 is excellent in flame retardancy and mechanical strength and suppresses bleeding (bleed-out). If the content of component B is too high, bleeding from the molded article may occur, and if the content of component B is too low, the impact strength may be insufficient.

[0028] In one embodiment of the present invention, the content of Component B is preferably 15 to 35% by mass, more preferably 17 to 32% by mass, and particularly preferably 20 to 30% by mass, relative to 100% by mass of the total content of Components A and B. If the content of Component B is too high, exudation from the molded article may occur, and if the content of Component B is too low, the impact strength may be insufficient.

[0029] The resin composition of the present invention may contain, in addition to the phosphoric acid ester plasticizer, other plasticizers within the range that does not impair 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; triacetin, diacetylglycerin, tripropionitrile glycerin, and glycerin monostearate. aliphatic dicarboxylic acid dialkyl esters such as dibutyl adipate, dioctyl adipate, dibutyl azelate, dioctyl azelate, 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 derivatives thereof; 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.

[0030] <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 combination of carboxylic acid and alcohol and the hydroxycarboxylic acid, it is possible to synthesize a variety of polyesters. The polyester is preferably polybutylene succinate, polybutylene succinate adipate, polylactic acid, poly(3-hydroxybutyrate-co-3-hydroxyvalerate), polybutylene adipate terephthalate, polycaprolactone, or a mixture thereof, more preferably selected from the group consisting of polybutylene succinate, polybutylene succinate adipate, and polylactic acid, and particularly preferably polybutylene succinate.

[0031] In the resin composition of the present invention, the content of component C is preferably 0.5% by mass or more, more preferably 1% by mass or more, and particularly preferably 3% by mass or more, relative to 100% by mass of the total content of components A, B, and C. Furthermore, the content is preferably 10% by mass or less, more preferably 7% by mass or less, and particularly preferably 6% by mass or less, relative to 100% by mass of the total content of components A, B, and C. By ensuring that the content of component C is within this range, bleeding out of component B can be suppressed. 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 bleeding out of component B may be insufficient.

[0032] In one embodiment of the present invention, the content of component C is preferably 6 to 8 mass%, more preferably 6.2 to 7.8 mass%, and particularly preferably 6.5 to 7.7 mass%, relative to 100 mass% of the total content of components A and C. When the content of component C is 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.

[0033] Increasing the content of Component B can improve flame retardancy and mechanical strength (impact resistance), but if the content of Component B is high, exudation may occur in high-temperature, high-humidity environments. Therefore, by adding Component C, exudation can be suppressed and the amount of Component B can be increased. Therefore, by containing Component A, Component B, and Component C, the resin composition of the present invention achieves both mechanical strength and suppression of exudation.

[0034] <Component D: Metal Hydroxide> The resin composition of the present invention contains a metal hydroxide as component D. By containing a metal hydroxide, the resin composition can have improved flame retardancy.

[0035] Examples of metal hydroxides include aluminum hydroxide, magnesium hydroxide, and calcium 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 resin and phenol resin. One type of metal hydroxide may be used alone, or two or more types may be used in combination.

[0036] 50% particle diameter of metal hydroxide (median diameter, D ５０ ) is not particularly limited, but is preferably 0.5 μm or more and 20 μm or less, more preferably 1 μm or more and 10 μm or less, and even more preferably 2 μm or more and 4 μm or less. When the 50% particle size of the metal hydroxide is within this range, it has excellent dispersibility in the resin composition, leading to improved flame retardancy and mechanical properties. If the 50% particle size of the metal hydroxide is too small, the viscosity of the resin composition may increase and the moldability may decrease. Furthermore, the increased viscosity may increase the shear force during kneading and molding, which may cause deterioration of other components. On the other hand, if the 50% particle size of the metal hydroxide is too large, unevenness may occur on the surface of the resin composition, reducing the design properties. The average particle size of the metal hydroxide can be determined, for example, by measuring the volume-based median diameter using a diffraction / scattering method.

[0037] In the resin composition of the present invention, the content of component D is preferably 0.5% by mass to 20% by mass, and more preferably 0.5% by mass to 17.5% by mass, relative to 100% by mass of the total amount of the resin composition. If the content of component D is too low, the flame retardancy may be insufficient. On the other hand, if the content of component D is too high, the toughness may decrease, resulting in a resin composition with poor mechanical properties.

[0038] When the resin composition does not contain Component E (described later), the content of Component D is preferably 0.5% by mass to 10% by mass, and more preferably 0.5% by mass to 5% by mass, relative to 100% by mass of the total amount of the resin composition. By ensuring that the content of Component D is within this range, a certain level of flame retardancy can be ensured and (relatively) good mechanical strength (impact resistance) can be obtained.

[0039] On the other hand, when Component E is contained, the content of Component D is preferably 10% by mass to 20% by mass, and more preferably 10% by mass to 17.5% by mass, relative to 100% by mass of the total amount of the resin composition. By having the content of Component D within this range, good flame retardancy and a certain level of mechanical strength (impact resistance) can be obtained.

[0040] <Component E: Anti-Drip Agent> The resin composition of the present invention preferably further contains an anti-drip agent as component E. By including component E, the resin composition shrinks when heated, preventing the molten resin from dripping (drip) and spreading the combustion. The anti-drip agent is preferably a fluorine-based anti-drip agent (fluoropolymer), and more preferably contains a fluoropolymer that forms a fibrous structure (fibril structure) in the resin composition. By incorporating a fluoropolymer, the effect of suppressing the drip phenomenon during combustion can be enhanced.

[0041] Examples of anti-drip agents include fluorine-based resins such as polytetrafluoroethylene, tetrafluoroethylene copolymers (e.g., tetrafluoroethylene / hexafluoropropylene copolymers), acrylic-modified polytetrafluoroethylene, polyvinylidene fluoride, and polyhexafluoropropylene; and alkali metal salt compounds of perfluoroalkanesulfonic acid, such as sodium perfluoromethanesulfonate, potassium perfluoro-n-butanesulfonate, potassium perfluoro-t-butanesulfonate, sodium perfluorooctanesulfonate, and calcium perfluoro-2-ethylhexanesulfonate, or alkaline earth metal salts of perfluoroalkanesulfonic acid. Furthermore, various forms of fluoropolymers can also be used as the fluorine-containing polymer, such as fine powder fluoropolymers, aqueous dispersions of fluoropolymers, mixtures of powdered fluoropolymers and acrylonitrile-styrene copolymers, and mixtures of powdered fluoropolymers and polymethyl methacrylate. Similarly, other anti-drip agents, such as silicone compounds such as silicone rubbers, and layered silicates such as talc, may also be blended. These may be used alone or in combination of two or more.

[0042] Among these, fluorine-based anti-drip agents having fibril-forming ability are preferred, with polytetrafluoroethylene being particularly preferred. The molecular weight of the fluorine-based anti-drip agent (particularly polytetrafluoroethylene) is preferably 1,000,000 to 10,000,000, more preferably 2,000,000 to 9,000,000, in terms of number average molecular weight determined from standard specific gravity. Such polytetrafluoroethylene may be in the form of a solid or an aqueous dispersion.

[0043] In the resin composition of the present invention, the content of Component E is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and even more preferably 0.3% by mass or more, relative to 100% by mass of the total amount of the resin composition, and is preferably 2% by mass or less, more preferably 1.5% by mass or less, and even more preferably 1.0% by mass or less. By having the content of Component E within this range, flame retardancy is further improved.

[0044] In one embodiment of the present invention, the content of Component E is preferably 0.1 to 10 mass%, more preferably 0.3 to 7 mass%, and particularly preferably 0.5 to 5 mass%, relative to 100 mass% of Component D. When the content of Component E is within this range, flame retardancy is further improved.

[0045] <Component F: Inorganic or Organic Granular or Fibrous Filler> The resin composition of the present invention preferably contains an inorganic or organic granular or fibrous filler as Component F. By adding such a filler, mechanical strength and rigidity can be further improved. 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.

[0046] In one aspect of this embodiment, the resin composition preferably contains 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. It is also preferably 20% by mass or less, more preferably 10% by mass or less, and even more preferably 8% by mass or less.

[0047] In the resin composition of the present invention, the content of component F is preferably 1% by mass or more, more preferably 2% by mass or more, and particularly preferably 3% by mass or more, based on 100% by mass of the total amount of the resin composition. Furthermore, the content of component F is preferably 10% by mass or less, more preferably 8% by mass or less, and particularly preferably 5% by mass or less, based on 100% by mass of the total amount of the resin composition. By having the content of component F within this range, the resin composition can sufficiently achieve the effect of improving the mechanical strength.

[0048] In one embodiment of the present invention, the resin composition may contain a colorant such as a black colorant. The content of the colorant such as a black colorant is not limited, but can be set in the range of 0.01 to 10 phr relative to the total mass of components other than the colorant (0.01 to 10 parts by mass per 100 parts by mass of the total mass of components other than the colorant in the resin composition). From the viewpoint of obtaining a sufficient coloring effect, the content of the colorant is preferably 0.05 phr or more, and more preferably 0.1 phr or more, relative to the total mass of components other than the colorant. From the viewpoint of suppressing the excess amount of colorant while obtaining a sufficient coloring effect, the content is preferably 5 phr or less, more preferably 3 phr or less, and even more preferably 2 phr or less. Furthermore, from the viewpoint of appearance such as gloss, the content of the colorant is preferably 1 phr or less, more preferably 0.3 phr or less, even more preferably 0.2 phr or less, and particularly preferably 0.1 phr or less.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] Examples of the aliphatic monocarbodiimide include diisopropylcarbodiimide, dimethylcarbodiimide, diisobutylcarbodiimide, and dioctylcarbodiimide.

[0054] Examples of alicyclic monocarbodiimides include dicyclohexylcarbodiimide.

[0055] Examples of aromatic monocarbodiimides include N,N'-diphenylcarbodiimide and N,N'-di-2,6-diisopropylphenylcarbodiimide.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] The hydrolysis inhibitors may be used alone or in combination of two or more.

[0062] 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.

[0063] The resin composition may contain, as other components, additives commonly used in ordinary molding resin materials, provided that the purpose of the present invention is not impaired. Examples of such additives include colorants, phenolic or phosphorus-based antioxidants, light stabilizers, UV absorbers, antistatic agents, antibacterial and antifungal agents, and fillers. In particular, the resin composition may contain additives commonly used in ordinary cellulose resins.

[0064] [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, component C, and component D, 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.

[0065] [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. Meanwhile, 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.

[0066] 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.

[0067] The molded article formed using the resin composition according to the present invention has excellent design properties and 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 for automobiles.

[0068] 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.

[0069] 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.

[0070] The present invention will be described in more detail below with reference to specific examples, but the present invention is not limited to these.

[0071] The components used in producing the resin compositions of the Examples and Comparative Examples are listed below. [Components of Resin Composition] The components used in producing the resin compositions of the Examples are listed below. <Component A: Cellulose acetate> (a1) 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> (b1) Triphenyl phosphate (manufactured by Daihachi Chemical Industry Co., Ltd., product name: TPP) <Component C: Polyester> (c1) Polybutylene succinate (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) <Component D: Metal hydroxide> (d1) Aluminum hydroxide (manufactured by Nippon Light Metal Co., Ltd., product name: BE023) (average particle size: 2 μm) <Component E: Anti-drip agent> (e1) Polytetrafluoroethylene (manufactured by Daikin Industries, Ltd., product name: POLYFLON MPA FA-500H) <Component F: Inorganic or organic granular or fibrous filler> Glass fiber (manufactured by Nittobo, product name: Chopped Strand CSG 3J-820, fiber length 3 mm, equivalent fiber diameter 11 μm *flat fiber)

[0072] [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).

[0073] [Evaluation Tests] The following evaluations were performed on the prepared evaluation samples. <Flame Retardancy (UL94V Test)> The combustion test was performed in accordance with the UL94 test (combustion test for plastic materials for equipment components) established by Underwriters Laboratories after injection-molded combustion test specimens (evaluation specimens 1 or 2) were left in a thermostatic chamber at 23°C and 50% humidity for 48 hours. 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. Flame retardancy is graded as 5V-A, 5V-B, V-0, V-1, V-2, and HB, in descending order of flame retardancy. A grade of V-2 or higher is considered good flame retardancy. V-0, V-1, and V-2 are shown in Table 1 below. (Evaluation Sample 1): Length 125 mm, width 13 mm, thickness 2.0 mm (Evaluation Sample 2): Length 125 mm, width 13 mm, thickness 3.2 mm

[0074]

[0075] 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.

[0076] <Charpy Impact Value 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)).

[0077] <Deflection temperature under load test> In accordance with JIS K 7191-2-2007, the oil temperature was raised at a constant rate (120°C / h), and a bending stress of 1.80 MPa was applied to an evaluation sample having a length of 80 mm, a width of 10 mm, and a thickness of 4.0 mm. The temperature at which the specified deflection amount was reached was taken as the deflection temperature under load (support distance: 100 mm).

[0078] <Flexural Modulus Test> Using an evaluation sample having a length of 80 mm, a width of 10 mm and a thickness of 4.0 mm, the flexural modulus (GPa) was measured in accordance with JIS K 7171 (the average value of two samples was used).

[0079] <Exudation test> JIS K 7162 Test piece 1A-shaped evaluation sample 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 observed ×: Exudation observed

[0080]

[0081] As shown in Table 2, in Test Example 1, which did not contain Component C (polyester), exudation of the plasticizer occurred, but in Test Example 5, which contained Component C and Component D, exudation was suppressed. It was also confirmed that Test Example 5, which contained Component C and Component D, had a higher flexural modulus than Test Examples 2 to 4, which did not contain Component D (metal oxide). Test Example 5 also had good flame retardancy.

[0082]

[0083] As shown in Table 3, when the content of component B is 20 to 30% by mass relative to 100% by mass of the total content of components A, B, and C, the content of component C is 0.5 to 10% by mass relative to 100% by mass of the total content of components A, B, and C, and the content of component D is 0.5 to 10% by mass relative to the total composition, it was found that a molded article having excellent flame retardancy and mechanical strength and suppressed exudation of plasticizer can be obtained. In the case of a composition not containing component E (anti-drip agent), it was found that when the content of component D is 0.5 to 5% by mass relative to the total composition (Test Examples 6 and 7), even better results were obtained in mechanical strength (Charpy impact value).

[0084]

[0085] As shown in Table 4, it was confirmed that the incorporation of Component E (anti-drip agent) further improved flame retardancy, achieving a V-1 grade. It was found that the amount of Component E is preferably 0.1 to 0.5% by mass based on the total composition. Furthermore, it was found that when Component E is incorporated, the content of Component D is preferably 10 to 20% by mass based on the total composition.

[0086]

[0087] As shown in Table 5, it was confirmed that the deflection temperature under load increases and the mechanical strength is further improved by further blending Component F (an inorganic or organic granular or fibrous filler). Furthermore, it was found that the amount of Component F is preferably 1 to 10 mass% of the total composition.

[0088] 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.

[0089] 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.

[0090] (Appendix 1) A resin composition comprising: Component A: cellulose acetate; Component B: a plasticizer which is a phosphate ester; Component C: a polyester; and Component D: a metal hydroxide, wherein the content of Component B is 20 to 30% by mass relative to 100% by mass of the total content of Components A, B, and C; the content of Component C is 0.5 to 10% by mass relative to 100% by mass of the total content of Components A, B, and C; and the content of Component D is 0.5 to 20% by mass relative to the total content of the composition. (Appendix 2) The cellulose 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 resin composition according to Appendix 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 Component D is aluminum hydroxide. (Appendix 5) The cellulose-based resin composition according to any of the preceding appendices, wherein the content of Component D relative to the total composition is 0.5 to 10 mass%. (Appendix 6) The cellulose-based resin composition according to any of the preceding appendices, further comprising Component E: an anti-drip agent. (Appendix 7) The cellulose-based resin composition according to Appendix 6, wherein the content of Component E relative to the total composition is 0.01 to 2 mass%. (Appendix 8) The cellulose-based resin composition according to Appendix 6, wherein the content of Component D relative to the total composition is 10 to 20 mass%. (Appendix 9) The cellulose-based resin composition according to any one of the preceding Appendices, further comprising Component F: an inorganic or organic granular or fibrous filler. (Appendix 10) The cellulose-based resin composition according to any one of the preceding Appendices, wherein the content of Component B is 22 to 29% by mass relative to 100% by mass of the total content of Components A, B, and C. (Appendix 11) The cellulose-based resin composition according to any one of the preceding Appendices, wherein the content of Component B is 25 to 28% by mass relative to 100% by mass of the total content of Components A, B, and C. (Appendix 12) The cellulose-based resin composition according to any one of the preceding Appendices, wherein the content of Component C is 1 to 7% by mass relative to 100% by mass of the total content of Components A, B, and C. (Appendix 13) The cellulose-based resin composition according to any one of the preceding Appendices, wherein the content of Component C is 3 to 6% by mass relative to 100% by mass of the total content of Components A, B, and C. (Appendix 14) The cellulose-based resin composition according to any one of the preceding appendices, which contains Component E: an anti-drip agent, and the content of Component D is 10 to 17.5% by mass relative to 100% by mass of the total content of Components A, B, and C. (Appendix 15) The cellulose-based resin composition according to any one of the preceding appendices, which does not contain Component E: an anti-drip agent, and the content of Component D is 0.5 to 5% by mass relative to 100% by mass of the total content of Components A, B, and C.(Appendix 16) The cellulose-based resin composition according to any one of Appendices 9 to 15, wherein the content of Component F is 1 to 10% by mass, relative to 100% by mass of the total content of Components A, B, and C. (Appendix 17) The cellulose-based resin composition according to any one of the preceding Appendices, further comprising a hydrolysis inhibitor. (Appendix 18) The cellulose-based resin composition according to Appendices 17, 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 19) A resin composition comprising: Component A: cellulose acetate; Component B: a plasticizer which is a phosphate ester; Component C: a polyester; and Component D: a metal hydroxide, 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): a cellulose-based resin composition comprising: a cellulose ester resin composition according to claim 1, wherein the cellulose ester resin composition is a cellulose ester resin composition having a cellulose ester content of 0.5 to 20% by mass, and a cellulose ester resin composition having a cellulose ester content of 0.5 to 20% by mass, and wherein the cellulose ester resin composition is a cellulose ester resin composition having a cellulose ester content of 0.5 to 20% by mass, and wherein the cellulose ester resin composition is a cellulose ester resin composition having a cellulose ester content of 0.5 to 20% by mass, and wherein the cellulose ester resin composition is a cellulose ester resin composition having a cellulose ester content of 0.5 to 20% by mass, and wherein the cellulose ester resin composition is a cellulose ester resin composition having a cellulose ester content of 0.5 to 20% by mass, and wherein the cellulose ester resin composition is a cellulose ester resin composition having a cellulose ester content of 0.5 to 1 ... (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 Component D: a metal hydroxide, and a resin composition containing the same, with respect to a total content of 100% by mass of the Components A, B and C, the content of the Component B is 20 to 30% by mass, with respect to a total content of 100% by mass of the Components A, B and C, the content of the Component C is 0.5 to 10% by mass, a cellulose resin composition, wherein the content of the Component D with respect to the whole composition is 0.5 to 20% by mass.

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 1】

3. The 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 Component D is aluminum hydroxide.

5. The cellulose resin composition according to Claim 1 or 2, wherein the content of the Component D with respect to the whole composition is 0.5 to 10% by mass.

6. The cellulose resin composition according to Claim 1 or 2, further comprising Component E: an anti-dripping agent.

7. The cellulose resin composition according to Claim 6, wherein the content of the Component E with respect to the whole composition is 0.01 to 2% by mass.

8. The cellulose resin composition according to Claim 6, wherein the content of the Component D with respect to the whole composition is 10 to 20% by mass.

9. The cellulose resin composition according to Claim 1 or 2, further comprising Component F: an inorganic or organic granular or fibrous filler.

10. A molded article formed using the cellulose resin composition according to Claim 1 or 2.

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