Cellulose-based resin composition and molded article using the same

Abstract

To provide a cellulose-based resin composition that enables formation of a molded article exhibiting superior flame resistance and mechanical strength.SOLUTION: A cellulose-based resin composition comprising component A: cellulose acetate; component B: an organic compound containing phosphorus; component C: a plasticizer (excluding component B); component D: a flame retardant (excluding components B and C); and component E: a copolymer having a polar functional group.SELECTED DRAWING: None

Description

[Technical Field]

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

[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] A representative example of non-edible plant resources is cellulose, a major component of wood and plants. Various bioplastics have been developed and commercialized using cellulose esters, such as cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, and cellulose acetate phthalate.

[0004] For example, Patent Document 1 describes a porous film containing a polymer composition including cellulose ester, a plasticizer, an ethylene-methyl acrylate copolymer, and an impact modifier, and hollow glass microspheres. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special Publication No. 2021-501238 Summary of the Invention [Problem to be solved by the invention]

[0006] However, it has been difficult to achieve both flame retardancy and mechanical strength (impact resistance, etc.) in molded articles formed using cellulose acetate-based resin compositions.

[0007] In view of the above-mentioned problems, an object of the present disclosure is to provide a cellulose-based resin composition that can form a molded article having excellent flame retardancy and strength. [Means for solving the problem]

[0008] In order to achieve the above object, the present disclosure provides: Component A: cellulose acetate, Component B: an organic compound containing phosphorus; Component C: Plasticizer (excluding component B), Component D: flame retardant (excluding components B and C), Component E: a copolymer having a polar functional group; The cellulose-based resin composition comprises: [Effects of the Invention]

[0009] According to the present disclosure, it is possible to provide a cellulose-based resin composition that can form a molded article having excellent flame retardancy and strength. DETAILED DESCRIPTION OF THE INVENTION

[0010] [Resin composition] The resin composition of the present disclosure comprises: Component A: cellulose acetate, Component B: an organic compound containing phosphorus; Component C: Plasticizer (excluding component B), Component D: flame retardant (excluding components B and C), Component E: a copolymer having a polar functional group; The cellulose-based resin composition comprises:

[0011] <Component A: Cellulose acetate> The resin composition of the present disclosure contains cellulose acetate as component A. As the cellulose acetate, one in which acetyl groups have been introduced into at least some of the hydroxy groups of cellulose as a raw material 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] [ka]

[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, which may cause problems in molding.

[0016] Each glucose unit constituting cellulose has three hydroxy groups. The cellulose acetate in the present disclosure 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 (DS Ac ) (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, fluidity, etc., DS Ac is preferably 2.0 or more, more preferably 2.2 or more, and even more preferably 2.4 or more. In order to obtain 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, heat resistance, etc. of the resin composition. For example, the hydroxy group residual degree may be 0.01 or more, or 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, impact resistance, etc., 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 disclosure, the content of Component A is preferably 30% by mass or more, more preferably 35% by mass or more, and particularly preferably 40% by mass or more, based on 100% by mass of the total content of Components A, B, C, D, and E. Furthermore, the content of Component A is preferably 80% by mass or less, more preferably 75% by mass or less, and particularly preferably 70% by mass or less, based on 100% by mass of the total content of Components A, B, C, D, and E.

[0023] <Component B: Phosphorus-containing organic compounds> The resin composition of the present disclosure includes a phosphorus-containing organic compound as Component B. Component B may be used singly or in combination of two or more. Component B may include, but is not limited to, one or more phosphate esters selected from the group consisting of triphenyl phosphate (TPP), triethyl phosphate, tributyl phosphate, tricresyl phosphate, cresyl di-2,6-xylenyl phosphate, and compounds represented by the following formula (2):

[0024] [ka]

[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 an organic compound containing phosphorus, a resin composition with high strength can be formed.

[0026] In one embodiment of the present disclosure, Component B is more preferably triphenyl phosphate from the viewpoint of flame retardancy and high compatibility with cellulose acetate.

[0027] In the resin composition of the present disclosure, the content of component B is preferably 5% by mass or more, more preferably 6% by mass or more, and particularly preferably 7% by mass or more, based on 100% by mass of the total content of components A, B, C, D, and E. Furthermore, the content of component B is preferably 20% by mass or less, more preferably 15% by mass or less, and particularly preferably 12% by mass or less, based on 100% by mass of the total content of components A, B, C, D, and E. By ensuring that 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 strength and that suppresses bleeding out. If the content of component B is too high, bleeding from the molded article may occur in a high-temperature, high-humidity environment, while if the content of component B is too low, the flame retardancy may be insufficient.

[0028] <Component C: Plasticizer> The resin composition of the present disclosure contains a plasticizer as Component C. Component C may be used alone or in combination of two or more types. Examples of component C include, but are not limited to, polyether ester plasticizers composed of a polyester of a polyether such as polyethylene glycol or polypropylene glycol and a dibasic acid such as 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; adipate ester plasticizers such as dioctyl adipate and diisononyl adipate; phthalate ester plasticizers such as dibutyl phthalate, diaryl phthalate, diethyl phthalate, dimethyl phthalate, di-2-methoxyethyl phthalate, ethyl phthalyl ethyl glycolate, and methyl phthalyl ethyl glycolate; tartrate ester plasticizers such as dibutyl tartrate; triacetin, diacetyl glycerin, tripropionitrile glycerin, glyceryl polyhydric alcohol ester-based plasticizers such as ethanol monostearate; aliphatic dicarboxylic acid dialkyl ester-based plasticizers such as dibutyl adipate, dioctyl adipate, dibutyl azelate, dioctyl azelate, and dioctyl sebacate; citrate ester-based plasticizers such as triethyl citrate, acetyl triethyl citrate, and acetyl tributyl citrate; epoxidized vegetable oil-based plasticizers such as epoxidized soybean oil and epoxidized linseed oil; castor oil and its derivative-based plasticizers; benzoate ester-based plasticizers such as ethyl O-benzoylbenzoate; aliphatic dicarboxylic acid ester-based plasticizers such as sebacic acid esters and azelaic acid esters; unsaturated dicarboxylic acid ester-based plasticizers such as maleic acid esters; and others such as N-ethyltoluenesulfonamide, O-cresyl p-toluenesulfonate, and tripropionin.

[0029] The plasticizer of Component C is not particularly limited as long as it is compatible with cellulose acetate, but in one embodiment of the present disclosure, Component C is preferably triethyl citrate. In another embodiment of the present disclosure, Component C is preferably a polyetherester plasticizer.

[0030] In the resin composition of the present disclosure, the content of Component C is preferably 5% by mass or more, more preferably 10% by mass or more, and particularly preferably 15% by mass or more, relative to 100% by mass of the combined content of Components A and C. Furthermore, the content of Component C is preferably 40% by mass or less, more preferably 35% by mass or less, and particularly preferably 30% by mass or less, relative to 100% by mass of the combined content of Components A and C.

[0031] In the resin composition of the present disclosure, the content of component C is preferably 2% by mass or more, more preferably 3% by mass or more, and particularly preferably 4% by mass or more, relative to 100% by mass of the total content of components A, B, C, D, and E. Furthermore, the content of component C is preferably 20% by mass or less, more preferably 15% by mass or less, and particularly preferably 10% by mass or less, relative to 100% by mass of the total content of components A, B, C, D, and E. By ensuring that the content of component C is within this range, the resin composition can be used to obtain a molded article that is excellent in flame retardancy and strength and that suppresses bleeding out. If the content of component C is too high, bleeding from the molded article may occur in a high-temperature, high-humidity environment, while if the content of component C is too low, the strength may be insufficient.

[0032] In the resin composition of the present disclosure, the total content of Components B and C is preferably 20% by mass or more, more preferably 22% by mass or more, and particularly preferably 23% by mass or more, based on 100% by mass of the total content of Components A, B, and C. Furthermore, based on 100% by mass of the total content of Components A, B, and C, the total content is preferably 50% by mass or less, more preferably 45% by mass or less, and particularly preferably 40% by mass or less. When the total content of Components B and C is within this range, the resin composition can be used to obtain a molded article that has excellent flame retardancy and strength and suppresses bleeding out. If the total content of Components B and C is too high, bleeding from the molded article may occur in a high-temperature, high-humidity environment. If the total content of Components B and C is too low, the strength, flame retardancy, or fluidity may be insufficient.

[0033] <Component D: Flame retardant> The resin composition of the present disclosure contains a flame retardant as Component D. Component D may be used alone or in combination of two or more. Component D is not particularly limited, and examples of Component D that can be used include nitrogen-containing flame retardants, phosphorus-based inorganic flame retardants, halogen-based flame retardants, and boron-based flame retardants.

[0034] Examples of nitrogen-containing flame retardants include, but are not limited to, ammonium polyphosphate, melamine sulfate, guanidine phosphate, poly(melamine phosphate), piperazine pyrophosphate, and melamine cyanurate. From the viewpoint of improving water resistance, ammonium polyphosphate microencapsulated with melamine resin or the like can be used.

[0035] Phosphorus-based inorganic flame retardants include, but are not limited to, red phosphorus and ammonium polyphosphate.

[0036] Examples of halogen-based flame retardants include tetrabromobisphenol A (TBBA) compounds; polybenzene ring compounds such as 1,2-bis(2,4,6-tribromophenoxy)ethane, 2,4,6-tris(2,4,6-tribromophenoxy)-1,3,5-triazine, 2,6-dibromophenol, and 2,4-dibromophenol; brominated styrene compounds such as brominated polystyrene and polybrominated styrene; phthalic acid compounds such as ethylene bistetrabromophthalimide; cyclic aliphatic compounds such as hexabromocyclododecane; chlorinated paraffin, chlorinated polyethylene, dodecachloropentacyclooctadeca-7,15-diene, and PEG anhydride.

[0037] Examples of boron-based flame retardants include borax; boron oxides such as diboron trioxide, boron trioxide, diboron dioxide, tetraboron trioxide, and tetraboron pentoxide; and boric acid compounds such as boric acid, lithium borate, sodium borate, potassium borate, cesium borate, magnesium borate, calcium borate, barium borate, zirconium borate, zinc borate, aluminum borate, and ammonium borate.

[0038] From the viewpoints of flame retardancy and strength, component D is preferably a nitrogen-containing flame retardant, more preferably at least one selected from the group consisting of ammonium polyphosphate, melamine sulfate, guanidine phosphate, melamine polyphosphate, piperazine pyrophosphate, and melamine cyanurate, and particularly preferably melamine cyanurate.

[0039] In the resin composition of the present disclosure, the content of component D is preferably 5% by mass or more, more preferably 10% by mass or more, and particularly preferably 15% by mass or more, relative to 100% by mass of the total content of components A, B, C, D, and E. Furthermore, the content of component D 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, C, D, and E. By ensuring that the content of component D is within this range, the resin composition can be used to obtain a molded article with excellent flame retardancy and strength. If the content of component D is too high, moldability or toughness (Charpy impact value) may decrease. If the content of component D is too low, flame retardancy may be insufficient.

[0040] <Component E: Copolymer having polar functional groups> The resin composition of the present disclosure includes a copolymer having a polar functional group as Component E. Component E may be used singly or in combination of two or more. Examples of the polar functional group include, but are not limited to, maleic anhydride groups, amino groups, quaternary ammonium groups, epoxy groups, carboxyl groups, sulfo groups, phosphate groups, hydroxyl groups, nitro groups, and thiol groups, with maleic anhydride groups being preferred. The copolymer may be any of alternating copolymers, random copolymers, block copolymers, and graft copolymers, and examples thereof include ethylene copolymers, propylene copolymers, and butene copolymers, with ethylene copolymers being preferred.

[0041] In one embodiment of the present disclosure, Component E is preferably a maleic anhydride-modified hydrogenated styrene-based thermoplastic elastomer (specifically, a maleic anhydride-modified styrene-ethylene-butylene-styrene block copolymer (SEBS)). In another embodiment of the present disclosure, Component E is preferably an ethylene-acrylic acid ester-maleic anhydride terpolymer.

[0042] In the resin composition of the present disclosure, the content of component E is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and particularly preferably 0.1% by mass or more, relative to 100% by mass of the total content of components A, B, C, D, and E. Furthermore, the content of component E is preferably 5% by mass or less, more preferably 4% by mass or less, and particularly preferably 3% by mass or less, relative to 100% by mass of the total content of components A, B, C, D, and E. By ensuring that the content of component E is within this range, a molded article with excellent strength can be obtained. It is surprising that improved strength can be achieved simply by blending such a small amount of a copolymer having a polar functional group.

[0043] <Inorganic or organic granular or fibrous fillers> In one aspect of this embodiment, the resin composition preferably contains an inorganic or organic granular or fibrous filler, particularly preferably glass fiber, which improves the strength of the molded article.

[0044] 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 thereof include circular, elliptical, oval, 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.

[0045] Examples of inorganic or organic granular or fibrous fillers other than glass fiber 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 (asbestos fibers, carbon fibers, silica fibers, silica-alumina fibers, wollastonite, zirconia fibers, potassium titanate fibers, etc.), and metal fibers.

[0046] The content of the inorganic or organic granular or fibrous filler may be 0% by mass relative to 100% by mass of the total amount of the resin composition, but is, for example, preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, and the content of the inorganic or organic granular or fibrous filler is preferably 40% by mass or less, more preferably 30% by mass or less, and even more preferably 25% by mass or less relative to 100% by mass of the total amount of the resin composition. By having the content of the inorganic or organic granular or fibrous filler within this range, the resin composition can fully achieve the effect of improving its strength.

[0047] <Hydrolysis inhibitor> 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.

[0048] 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.

[0049] 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 less carbodiimide groups. 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.

[0050] 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.

[0051] Examples of aliphatic monocarbodiimides include diisopropylcarbodiimide, dimethylcarbodiimide, diisobutylcarbodiimide, and dioctylcarbodiimide. Examples of alicyclic monocarbodiimides include dicyclohexylcarbodiimide. Examples of aromatic monocarbodiimides include N,N'-diphenylcarbodiimide and N,N'-di-2,6-diisopropylphenylcarbodiimide.

[0052] 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. 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.

[0053] 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.

[0054] As the carbodiimide compound, commercially available products may be used, such as 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.

[0055] 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.

[0056] The content of the hydrolysis inhibitor may be 0% by mass relative to 100% by mass of the total amount of the resin composition, but is, for example, preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and is preferably 3% by mass or less, more preferably 1% by mass or less, relative to 100% by mass of the total amount of the resin composition. One type of hydrolysis inhibitor may be used alone, or two or more types may be used in combination.

[0057] <Flame retardant auxiliary (anti-drip agent)> The resin composition of the present disclosure preferably further contains a flame retardant aid, which causes the resin composition to shrink when heated, preventing the molten resin from dripping and spreading the fire.

[0058] Examples of flame retardant aids include fluororesins such as polytetrafluoroethylene, tetrafluoroethylene copolymers (e.g., tetrafluoroethylene / hexafluoropropylene copolymers), acrylic-modified polytetrafluoroethylene, polyvinylidene fluoride, and polyhexafluoropropylene; and alkali metal salts of perfluoroalkanesulfonic acids or alkaline earth metal salts of perfluoroalkanesulfonic acids, such as sodium perfluoromethanesulfonate, potassium perfluoro-n-butanesulfonate, potassium perfluoro-t-butanesulfonate, sodium perfluorooctanesulfonate, and calcium perfluoro-2-ethylhexanesulfonate. Furthermore, various forms of fluoropolymers can be used, 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 flame retardant aids, such as silicone compounds (e.g., silicone rubbers) and layered silicates (e.g., talc), can also be used. These may be used alone or in combination of two or more.

[0059] As the flame retardant aid, a fluorine-based flame retardant aid that forms a fibrous structure (fibril-like structure) in the resin composition is preferred, with polytetrafluoroethylene being particularly preferred. By incorporating a fluorine-based flame retardant aid, the effect of suppressing dripping during combustion can be enhanced. The molecular weight of the fluorine-based flame retardant aid (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 the standard specific gravity. Such polytetrafluoroethylene may be in the form of a solid or an aqueous dispersion.

[0060] In the resin composition of the present disclosure, the content of the flame retardant aid may be 0% by mass, but is preferably 0.01% by mass or more, more preferably 0.02% by mass or more, and even more preferably 0.05% by mass or more, relative to 100% by mass of the total amount of the resin composition, and is preferably 3% by mass or less, more preferably 2% by mass or less, even more preferably 1% by mass or less, and even more preferably 0.2% by mass or less, relative to 100% by mass of the total amount of the resin composition. By having the content of the flame retardant aid within this range, flame retardancy is further improved.

[0061] <Coloring agent> In one embodiment of the present disclosure, 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 (0.01 to 10 parts by mass per 100 parts by mass of the total mass of the components other than the colorant) relative to the total mass of the components other than the colorant. To obtain 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 the components other than the colorant. To suppress excess 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. These colorants can be used alone or in combination.

[0062] The resin composition may contain, as other components, additives commonly used in ordinary molding resin materials, provided that the purpose of the present disclosure is not impaired. Examples of such additives include phenolic or phosphorus-based antioxidants, light stabilizers, UV absorbers, antistatic agents, antibacterial and antifungal agents, etc. In particular, the resin composition may contain additives commonly used in ordinary cellulose resins.

[0063] [Method of producing resin composition] The method for producing the resin composition of the present disclosure is not particularly limited, and for example, the resin composition can be obtained by melt-mixing component A, component B, component C, component D, and component E, and other components as needed, in a conventional mixer. Examples of the mixer that can be used include compounding devices such as a tumbler mixer, ribbon blender, single-screw or multi-screw mixer extruder, kneading kneader, and kneading roll. After melt-mixing, the mixture can be granulated into an appropriate shape as needed, and can be pelletized using a pelletizer, for example.

[0064] [Molded body] Molded articles formed using the resin composition according to the present disclosure can be molded into the 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 set appropriately depending on the desired shape, strength, etc., but can be, for example, 10 mm or less, or even 5 mm or less.

[0065] The resin composition according to the present disclosure 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 heat press molding.

[0066] Molded articles formed using the resin composition according to the present disclosure have 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, they can be used in housings and exterior parts of electronic devices and home appliances, interior building materials, and automobile interior materials.

[0067] Applications for electronic devices and home appliances include housings for computers, landlines, mobile phones, smartphones, tablets, POS terminals, routers, projectors, speakers, lighting equipment, copiers, multifunction printers, calculators, remote controls, refrigerators, washing machines, humidifiers, dehumidifiers, video recorders / 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.

[0068] 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. [Example]

[0069] The present disclosure will be described in more detail below using specific examples, but the present disclosure is not limited to these.

[0070] The components used in producing the resin compositions of the Examples and Comparative Examples are shown below. [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 (substitution degree) DS = 2.4, acetylation degree: 55%, polymerization degree based on 6% viscosity: 180) <Component B: Phosphorus-containing organic compounds> Triphenyl phosphate (manufactured by Daihachi Chemical Industry Co., Ltd., product name: TPP) <Component C: Plasticizer> Polyetherester plasticizer (ADEKA Corporation, product name: Adeka Cizer RS-1000) <Component D: Flame retardant> Melamine cyanurate (Nissan Chemical Co., Ltd., product name: MC-4500) <Component E: Copolymer having polar functional groups> Hydrogenated styrene-based thermoplastic elastomer (maleic anhydride modified) (manufactured by Asahi Kasei Corporation, product name: Tuftec M1913) <Component E': Copolymer with no polar functional group> Hydrogenated styrene-based thermoplastic elastomer (manufactured by Asahi Kasei Corporation, product name: Tuftec H1221) <Glass fiber> Glass fiber (manufactured by Nittobo, product name: chopped strand CSG 3PA-820, fiber length 3 mm, equivalent fiber diameter 15 μm flat fiber) <Hydrolysis inhibitor> Aromatic carbodiimide (product name: Stabaxol P-100, manufactured by Lanxess) <Flame retardant synergist> Polytetrafluoroethylene (manufactured by Daikin Industries, Ltd., product name: Polyflon MPA FA-500H)

[0071] [Production of molded body] The constituent materials were thoroughly mixed by hand mixing at the blending ratios shown in Table 2. The units of the numerical values ​​relating to the blending ratios are mass % relative to the total composition. The resulting mixture was placed in a co-rotating twin-screw extruder (manufactured by STEER, product name: Omega30H [φ30, L / D=60]), kneaded at a kneading temperature of 200°C and a rotation speed of 240 rpm, air-cooled, recovered, and pelletized. The obtained pellets were dried again at 80°C for 5 hours immediately before molding and used to produce molded bodies of specified dimensions (evaluation sample: length 125 mm, width 13 mm, thickness 3.2 mm) using an injection molding machine (manufactured by Toshiba Machine, product name: EC20P).

[0072] [Evaluation test] The prepared evaluation samples were subjected to the following evaluations. <Flame retardancy (UL94V test)> Flame tests were conducted in accordance with the UL94 test (flame test for plastic materials for equipment components) established by Underwriters Laboratories, after injection-molded flame-test specimens (evaluation samples) were left in a temperature-controlled room at 23°C and 50% humidity for 48 hours. UL94V is a method of evaluating flame retardancy by applying a burner flame (20±1mm flame) to the bottom of a vertically held test specimen of a specified size for 10 seconds, and then measuring the subsequent burning time and drip rate. Flame retardancy is graded V-0, V-1, and V-2, ranked from best to worst. V-0, V-1, and V-2 are shown in Table 1 below.

[0073] [Table 1]

[0074] The flaming burn 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 application, t2 is the burning time after the second flame application, and t3 is the afterglow (flameless burning) time after the second flame application. The second flame application is performed by immediately applying the burner flame to the test specimen for 10 seconds if the flame goes out after the first flame application. The ignition of cotton by dripping is determined by whether the cotton marking located 300±10 mm below the bottom edge of the test specimen is ignited by dripping material from the test specimen.

[0075] <Charpy impact value test> Using an evaluation sample having the shape of JIS K 7162 test piece 1A, a Charpy impact test was carried out in accordance with JIS K7111-1 (notched: Type A (notch cutter tip R0.25 mm)).

[0076] [Table 2]

[0077] As shown in Table 2, the Charpy impact value increased (5 to 6) in Test Examples 1 and 2, which used copolymers with polar functional groups, compared with Test Example 4, which did not use a copolymer with polar functional groups, and Test Example 3, which used a copolymer without polar functional groups, confirming that both flame retardancy and strength were achieved. Furthermore, Test Example 1, in which the content of the copolymer with polar functional groups was 1.00% by mass, and Test Example 3, in which the content of the copolymer with polar functional groups was 3.00% by mass, had comparable flame retardancy and Charpy impact value results, confirming that the content of Component E is preferably 0.01 to 5% by mass relative to the total content of Components A, B, C, D, and E (100% by mass). It is surprising that improved strength can be achieved by simply blending such a small amount of copolymer with polar functional groups.

[0078] Although the present disclosure has been described above with reference to the embodiments and examples, the present disclosure is not limited to the above-described embodiments and examples. Various modifications that can be understood by a person skilled in the art can be made to the configuration and details of the present disclosure within the scope of the present disclosure.

[0079] 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.

[0080] (Appendix 1) Component A: cellulose acetate, Component B: an organic compound containing phosphorus; Component C: Plasticizer (excluding component B), Component D: flame retardant (excluding components B and C), Component E: a copolymer having a polar functional group; A cellulose-based resin composition comprising: (Appendix 2) Component E is an ethylene copolymer, a propylene copolymer, or a butene copolymer having a polar functional group selected from the group consisting of maleic anhydride groups, amino groups, quaternary ammonium groups, epoxy groups, carboxyl groups, sulfo groups, phosphate groups, hydroxyl groups, nitro groups, and thiol groups. (Appendix 3) 3. The cellulose resin composition according to claim 1, wherein the content of the component E is 0.01 to 5% by mass relative to 100% by mass of the total amount of the composition. (Appendix 4) The cellulose-based resin composition according to any one of the preceding appendices, wherein the component C is a polyether ester-based plasticizer and / or a citrate ester-based plasticizer. (Appendix 5) The cellulose-based resin composition according to any of the preceding appendices, 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-xylenyl phosphate, and a compound represented by the following formula (2): [ka] (Appendix 6) The cellulose-based resin composition according to any one of the preceding appendices, wherein the total content of the components B and C is 20% by mass to 50% by mass, relative to 100% by mass of the total content of the components A, B, and C. (Appendix 7) The cellulose-based resin composition of any of the preceding paragraphs, wherein component D is a nitrogen-containing flame retardant. (Appendix 8) The cellulose-based resin composition according to any of the preceding appendices, further comprising an inorganic or organic granular or fibrous filler. (Appendix 9) 9. The cellulose resin composition according to claim 8, wherein the content of the inorganic or organic granular or fibrous filler is 5 to 40% by mass relative to 100% by mass of the total amount of the composition. (Appendix 10) A molded article formed using the cellulose resin composition according to any one of the preceding appendices. (Appendix 11) The cellulose resin composition according to any one of the preceding appendices, wherein the content of the component A is 30% by mass to 80% by mass relative to 100% by mass of the total content of the components A, B, C, D and E. (Appendix 12) The cellulose-based resin composition according to any of the preceding appendices, wherein component B is triphenyl phosphate. (Appendix 13) The cellulose resin composition according to any one of the preceding appendices, wherein the content of the component B is 5% by mass to 20% by mass relative to 100% by mass of the total content of the components A, B, C, D and E. (Appendix 14) The cellulose-based resin composition according to any of the preceding appendices, wherein component C is triethyl citrate. (Appendix 15) The cellulose-based resin composition according to any of the preceding appendices, wherein the component C is a polyetherester-based plasticizer. (Appendix 16) The cellulose resin composition according to any one of the preceding appendices, wherein the content of the component C is 5% by mass to 40% by mass relative to 100% by mass of the total content of the components A and C. (Appendix 17) The cellulose resin composition according to any one of the preceding appendices, wherein the content of the component C is 2% by mass to 20% by mass relative to 100% by mass of the total content of the components A, B, C, D and E. (Appendix 18) The cellulose-based resin composition according to any of the preceding appendices, wherein component D is at least one selected from the group consisting of ammonium polyphosphate, melamine sulfate, guanidine phosphate, poly(melamine phosphate), piperazine pyrophosphate, and melamine cyanurate. (Appendix 19) The cellulose resin composition according to any one of the preceding appendices, wherein the content of the component D is 5 to 35% by mass relative to the total content of the components A, B, C, D and E (100% by mass). (Appendix 20) The cellulose-based resin composition according to any one of the preceding appendices, wherein the component E is an ethylene copolymer having maleic anhydride groups. (Appendix 21) The cellulose-based resin composition according to any one of the preceding appendices, wherein the component E is a maleic anhydride-modified styrene-ethylene-butylene-styrene block copolymer. (Appendix 22) 10. The cellulose-based resin composition of any preceding claim, further comprising a hydrolysis inhibitor. (Appendix 23) 23. The cellulose-based resin composition according to claim 22, wherein the hydrolysis inhibitor is a compound having a functional group selected from a carbodiimide group, an epoxy group, and an oxazoline group. (Appendix 24) 24. The cellulose-based resin composition according to claim 22 or 23, wherein the hydrolysis inhibitor is an aromatic carbodiimide. (Appendix 25) 25. The cellulose resin composition according to any one of claims 22 to 24, wherein the content of the hydrolysis inhibitor is 0.1 to 3% by mass relative to 100% by mass of the total amount of the composition. (Appendix 26) 10. The cellulose-based resin composition of any of the preceding paragraphs, further comprising a flame retardant aid. (Appendix 27) 27. The cellulose-based resin composition according to claim 26, wherein the flame retardant aid is a fluorine-based flame retardant aid. (Appendix 28) 28. The cellulose-based resin composition according to claim 26 or 27, wherein the flame retardant aid is polytetrafluoroethylene. (Appendix 29) 29. The cellulose resin composition according to any one of Appendices 26 to 28, wherein the content of the flame retardant aid is 0.01 to 2% by mass relative to 100% by mass of the total amount of the composition.

Claims

1. Component A: cellulose acetate, Component B: a phosphorus-containing organic compound; Component C: plasticizer (excluding component B), Component D: a flame retardant (excluding components B and C); Component E: a copolymer having a polar functional group; A cellulose-based resin composition comprising:

2. 2. The cellulose-based resin composition according to claim 1, wherein the component E is an ethylene copolymer, a propylene copolymer, or a butene copolymer having a polar functional group selected from the group consisting of a maleic anhydride group, an amino group, a quaternary ammonium group, an epoxy group, a carboxyl group, a sulfo group, a phosphoric acid group, a hydroxyl group, a nitro group, and a thiol group.

3. 3. The cellulose-based resin composition according to claim 1, wherein the content of component E is 0.01 to 5% by mass relative to 100% by mass of the total content of components A, B, C, D and E.

4. 3. The cellulose-based resin composition according to claim 1, wherein the component C is a polyether ester-based plasticizer and / or a citrate ester-based plasticizer.

5. 3. The cellulose-based 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-xylenyl phosphate, and a compound represented by the following formula (2): 【Chemical 1】

6. The cellulose-based resin composition according to claim 1 or 2, wherein the total content of the components B and C is 20% by mass to 50% by mass, relative to 100% by mass of the total content of the components A, B, and C.

7. The cellulose-based resin composition according to claim 1 or 2, wherein the component D is a nitrogen-containing flame retardant.

8. The cellulose-based resin composition according to claim 1 or 2, further comprising an inorganic or organic granular or fibrous filler.

9. The cellulose-based resin composition according to claim 8, wherein the content of the inorganic or organic granular or fibrous filler is 5 to 40% by mass relative to 100% by mass of the total amount of the composition.

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

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