Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/02—Elements
  • C08K3/04—Carbon
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L1/00—Compositions of cellulose, modified cellulose or cellulose derivatives
  • C08L1/08—Cellulose derivatives
  • C08L1/10—Esters of organic acids, i.e. acylates
  • C08L1/12—Cellulose acetate
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L29/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an alcohol, ether, aldehydo, ketonic, acetal or ketal radical; Compositions of hydrolysed polymers of esters of unsaturated alcohols with saturated carboxylic acids; Compositions of derivatives of such polymers
  • C08L29/02—Homopolymers or copolymers of unsaturated alcohols
  • C08L29/04—Polyvinyl alcohol; Partially hydrolysed homopolymers or copolymers of esters of unsaturated alcohols with saturated carboxylic acids
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L31/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an acyloxy radical of a saturated carboxylic acid, of carbonic acid or of a haloformic acid; Compositions of derivatives of such polymers
  • C08L31/02—Homopolymers or copolymers of esters of monocarboxylic acids
  • C08L31/04—Homopolymers or copolymers of vinyl acetate

Definitions

• the present invention relates to a cellulose-based resin composition and a molded article using the same.
• Bioplastics which are made from plant components, can contribute to combating oil depletion and global warming, and are therefore used in durable products such as electronic devices and automobiles, in addition to general products such as packaging, containers, and textiles.
• a typical example of the raw material for the inedible parts is cellulose, a major component of wood and plants, and various bioplastics using this have been developed and commercialized. Also, among cellulose resins, cellulose acetate is widely produced industrially.
• Patent Document 1 discloses a transparent, water-soluble cellulose acetate-based resin composition that contains cellulose acetate with a total acetyl substitution degree of 0.4 to 1.6 and polyvinyl alcohol with a saponification degree of 50 mol % or more.
• Patent Document 1 (Table 4, etc.) describes that using cellulose acetate with a high degree of acetyl substitution causes cloudiness.
• Patent Document 1 (Table 4, etc.) describes that using cellulose acetate with a high degree of acetyl substitution causes cloudiness.
• there is a demand for using cellulose acetate with a high degree of acetyl substitution from the standpoint of water resistance, etc. and there has been a demand for the development of a cellulose-based resin composition that can form a molded product with excellent appearance even in such cases.
• the presently disclosed invention aims to provide a cellulose-based resin composition that contains cellulose acetate with a high degree of acetyl substitution and that can form a molded body with excellent appearance, and a molded body (molded product) using the same.
• One aspect of the present disclosure relates to the following:
• a cellulose-based resin composition comprising:
• the present disclosure provides a cellulose-based resin composition capable of forming molded articles with excellent appearance, and a molded article molded using the same.
• cellulose-based resin composition of the present disclosure is Cellulose acetate (A) having an acetyl substitution degree of 2.0 or more; At least one polymer (B) selected from the group consisting of polyvinyl acetate and polyvinyl alcohol having a saponification degree of 40 mol % or less;
• One embodiment of the cellulose-based resin composition of the present disclosure is a cellulose-based resin composition for molding.
• a large amount of plasticizer is often used, which causes problems such as seepage and evaporation of low molecular weight plasticizers.
• the inventors of the present application have revealed that when a polymeric resin additive such as polybutylene succinate is used as a plasticizer, cloudiness occurs, and molded articles with excellent appearance cannot be obtained.
• the cellulose-based resin composition of the present disclosure solves these problems and is capable of forming molded articles with excellent moldability and designability. Furthermore, the cellulose-based resin composition of the present disclosure has excellent thermal stability because the amount of volatile low molecular weight plasticizer used can be reduced.
• the cellulose-based resin composition of the present disclosure contains cellulose acetate having an acetyl substitution degree of 2.0 or more (also referred to as “component (A)”).
• component (A) also referred to as “component (A)”
• CA cellulose acetate
• Cellulose acetate can be made from cellulose as the raw material, with acetyl groups introduced into at least some of the hydroxyl groups.
• Cellulose is a linear polymer formed by polymerization of ⁇ -D-glucose molecules ( ⁇ -D-glucopyranose) via ⁇ (1 ⁇ 4) glycosidic bonds, as shown in the following formula (1).
• Each glucose unit that constitutes cellulose has three hydroxyl groups (n in the formula is a natural number).
• the cellulose acetate of this embodiment is such cellulose in which acetyl groups have been introduced using these hydroxyl groups.
• Cellulose is the main component of plants, and can be obtained by separating and processing other components such as lignin from plants.
• cotton e.g. cotton linters
• pulp e.g. wood pulp
• the shape, size and form of cellulose or its derivatives used as raw materials are preferably in powder form with an appropriate particle size and shape in terms of reactivity, solid-liquid separation and ease of handling.
• fibrous or powdered material with a diameter of 1 to 100 ⁇ m (preferably 10 to 50 ⁇ m) and a length of 10 ⁇ m to 100 mm (preferably 100 ⁇ m to 10 mm) can be used.
• the degree of polymerization of cellulose 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 and heat resistance 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.
• Cellulose acetate can be obtained by introducing acetyl groups into the hydroxyl groups of cellulose. Commercially available cellulose acetate can be used.
• 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 that is introduced in place of the hydrogen atom of the hydroxy group of cellulose.
• the acylating agent is a compound that has at least one functional group that can react with the hydroxy group in cellulose, and examples of such an acylating agent include compounds that have a carboxyl group, a carboxylic acid halide group, or a carboxylic acid anhydride group. Specific examples include aliphatic monocarboxylic acids (acetic acid), their acid halides, and their acid anhydrides (acetic anhydride).
• the average number of acetyl groups introduced per glucose unit of cellulose (also referred to as acetyl group introduction ratio, acetyl substitution degree, "DS"), i.e., the average number of hydroxy groups substituted with acetyl groups per glucose unit, is preferably 2.0 or more and can be set in the range of 2.0 to 3.0.
• DS AC is preferably 2.0 or more, more preferably 2.2 or more, and even more preferably 2.4 or more.
• DS AC is preferably 2.9 or less, more preferably 2.8 or less.
• the intermolecular forces (intermolecular bonds) of cellulose can be reduced, improving the plasticity of the cellulose acetate resin composition.
• the degree of acetyl substitution of cellulose acetate can be measured by a known method, and may be measured by the method described in Patent Document 1.
• the degree of acetyl substitution is determined by converting the degree of acetylation determined according to the method for measuring the degree of acetylation in ASTM: D-817-91 (test method for cellulose acetate, etc.) using the following formula. This is a general method for determining the degree of acetylation of cellulose acetate.
• DS 162.14 x AV x 0.01 / (60.052 - 42.037 x AV x 0.01)
• DS acetyl substitution degree
• AV acetylation degree (%)
• 500 mg of dried cellulose acetate (sample) is precisely weighed and dissolved in 50 ml of a mixed solvent of ultrapure water and acetone (volume ratio 4:1), after which 50 ml of 0.2 N aqueous sodium hydroxide is added and saponified at 25°C for 2 hours.
• AV acetylation degree
• AV(%) (A ⁇ B) ⁇ F ⁇ 1.201/sample weight(g)
• the degree of acetyl substitution of cellulose acetate may also be measured by propionylating the hydroxyl groups of cellulose acetate, dissolving it in deuterated chloroform, and measuring it by NMR.
• the average number of remaining hydroxyl groups per glucose unit of cellulose acetate can be set in the range of 0 to 1.0, and is preferably less than 1.0.
• Hydroxy groups may remain from the viewpoint of the maximum strength and heat resistance of the cellulose acetate resin composition, and for example, the hydroxyl group residual degree may be 0.01 or more, and may even be 0.1 or more.
• the hydroxyl group residual degree of the final cellulose acetate is preferably 1.0 or less, more preferably less than 1.0, more preferably 0.8 or less, and even more preferably 0.6 or less.
• the hydroxyl group residual degree is preferably 0.6 or less, more preferably 0.5 or less, even more preferably 0.4 or less, and especially preferably 0.2 or less.
• the molecular weight of cellulose acetate is preferably in the range of 10,000 to 400,000, 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 cellulose acetate resin composition will decrease, making processing difficult, and uniform mixing may be difficult. Conversely, if the molecular weight is too small, the physical properties of the cellulose acetate resin composition, such as impact resistance, may decrease. This weight average molecular weight can be determined by gel permeation chromatography (GPC) (commercially available standard polystyrene can be used as the standard sample).
• GPC gel permeation chromatography
• the resin composition of the present disclosure contains at least one polymer (B) (also referred to as "component (B)”) selected from the group consisting of polyvinyl acetate and polyvinyl alcohol having a degree of saponification of 40 mol% or less.
• component (B) the cellulose-based resin composition can improve the moldability of the resin composition, and the molded article obtained by molding the resin composition has excellent appearance (design).
• component (B) the amount of volatile plasticizer used can be reduced, so the composition has excellent thermal stability and is also preferable from the viewpoint of workability and reduction of environmental load.
• the amount of low-molecular-weight plasticizer used can be reduced, so that the exudation of the plasticizer can be prevented.
• Component (B) is at least one polymer selected from the group consisting of polyvinyl acetate and polyvinyl alcohol having a degree of saponification of 40 mol % or less, and preferably contains polyvinyl alcohol having a degree of saponification of 40 mol % or less.
• Component (B) may be one type of polymer or a combination of two or more types of polymers.
• Polyvinyl alcohol (also referred to as "PVA") is a saponification product of a vinyl ester polymer (a polymer having at least a vinyl ester as a polymerization component).
• the vinyl ester (vinyl ester monomer) is not particularly limited, but examples thereof include vinyl esters of fatty acids (e.g., alkanoic acid vinyl esters (preferably C 1-16 alkanoic acid vinyl esters) such as vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl caprylate, vinyl versatate, and vinyl monochloroacetate), and aromatic carboxylic acid vinyl esters (e.g., arene carboxylate vinyl esters (preferably C 7-12 arene carboxylate vinyl esters) such as vinyl benzoate).
• the vinyl esters may be used alone or in combination of two or more.
• the vinyl ester preferably contains at least a fatty acid vinyl ester (for example, a C 1-10 alkanoic acid vinyl ester such as vinyl formate, vinyl acetate, vinyl propionate, or vinyl butyrate), and from an industrial viewpoint, preferably contains vinyl acetate.
• the polyvinyl alcohol is preferably a compound obtained by saponifying polyvinyl acetate.
• the vinyl ester polymer may have a unit derived from another monomer (a monomer copolymerizable with vinyl ester) as necessary (may be modified with another monomer).
• the other monomer are not particularly limited, but include alkyl vinyl ethers (e.g., preferably C 1-16 alkyl vinyl ether), epoxy group-containing vinyl monomers ⁇ e.g., vinyl glycidyl ethers (e.g., allyl glycidyl ether, (meth)acryl glycidyl ether, 4-(meth)acrylamidophenyl glycidyl ether, 3-(meth)acrylamidophenyl glycidyl ether, N-glycidoxymethyl(meth)acrylamide, N-glycidoxyethyl(meth)acrylamide, N-glycidoxypropyl(meth)acrylamide, N-glycidoxybutyl(meth)acrylamide, 4-(meth)acrylamidomethyl-2,
• Examples of the other monomers include, but are not limited to, unsaturated acid salts [e.g., alkali metal salts (e.g., sodium salts, potassium salts, ammonium salts, etc.)], glycidyl group-containing monomers [e.g., allyl glycidyl ether, glycidyl (meth)acrylate, etc.], sulfonic acid group-containing monomers (e.g., 2-acrylamido-2-methylpropanesulfonic acid, salts thereof, etc.), phosphoric acid group-containing monomers [e.g., acid phosphooxyethyl (meth)acrylate, acid phosphooxypropyl (meth)acrylate, etc.], allyl alcohol, diacetone (meth)acrylamide, etc.
• the other monomers may be used alone or in combination of two or more.
• the structural units derived from vinyl esters and structural units derived from other monomers may be modified to the extent that the effects of the present invention are not impaired.
• Modifications of units derived from vinyl esters may be, for example, acetalization, etherification, acetoacetylation, cationization, polyoxyalkylene modification, etc.
• Modifications of units derived from other monomers may be, for example, ring-opening reactions of epoxy groups (for example, reactions of epoxy groups with thiols), etc.
• the method for producing PVA is not particularly limited, and may be a known method such as a method of saponifying a vinyl ester polymer (preferably polyvinyl acetate).
• the polymerization method for vinyl ester polymer is not particularly limited, and may be, for example, the conventionally known bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization, etc., but solution polymerization (e.g., solution polymerization using methanol as a solvent, etc.) is industrially preferred.
• Suitable initiators such as peroxides and azos can be used, and the degree of polymerization of the obtained vinyl ester polymer can be adjusted by changing the compounding ratio of the vinyl ester monomer and the solvent and the polymerization yield.
• a commercially available PVA may be used.
• a known saponification method using an alkali catalyst or an acid catalyst can be used.
• an alkali such as sodium hydroxide
• a method in which an alkali such as sodium hydroxide is added to a methanol solution of a vinyl ester polymer or a mixed solution of a vinyl ester polymer in methanol, water, methyl acetate, etc., and alcoholysis is carried out while stirring and mixing is preferred from an industrial perspective. Thereafter, the obtained lump, gel, or granular material is crushed, the added alkali is neutralized as necessary, and the solid and liquid components are separated, and the solid is dried to obtain PVA.
• the timing of modification is not particularly limited, and it may be before or after the saponification of the vinyl ester polymer.
• the degree of saponification of the PVA of this embodiment is preferably 40 mol% or less, more preferably 38 mol% or less.
• the lower limit of the degree of saponification of the PVA is not particularly limited, but is preferably 0.5 mol% or more, more preferably 1 mol% or more, more preferably 3 mol% or more, even more preferably 8 mol% or more, even more preferably 20 mol% or more, even more preferably 30 mol% or more, and may be 35 mol% or more.
• the degree of saponification of the PVA is 40 mol% or less, the transparency is high when mixed with cellulose acetate of component (A), and the haze value can be reduced, and a molded body with excellent appearance can be produced. If the transparency of the molded body obtained from the mixture of component (A) and PVA is high, a molded body with good color development and excellent appearance can be obtained even when a colorant is contained. On the other hand, if the degree of saponification of the PVA is too high, mixing with cellulose acetate may cause cloudiness.
• the resin composition contains a partially saponified vinyl ester polymer (preferably polyvinyl acetate)
• the PVA has hydroxyl groups, which makes it easier for interactions such as hydrogen bonds to occur with cellulose acetate, making them more compatible.
• the degree of saponification and average degree of polymerization of polyvinyl alcohol can be measured by a method conforming to JIS K6726.
• the degree of saponification and the degree of polymerization when polyvinyl acetate is partially saponified are expressed by the following formula.
• the average degree of polymerization of polyvinyl acetate and polyvinyl alcohol is not particularly limited, but is preferably 100 or more, more preferably 150 or more, and even more preferably 200 or more, and is preferably 3000 or less, more preferably 2000 or less, even more preferably 1500 or less, even more preferably 1000 or less, and even more preferably 500 or less. If the degree of polymerization of the polymer of component (B) is too low, bleeding may occur easily, while if the degree of polymerization is too high, the thermoplasticity (processability) of the resin composition may decrease.
• the average degree of polymerization of polyvinyl acetate and the average degree of polymerization of polyvinyl alcohol can be measured, for example, by the method specified in JIS K6725 and JIS K6726.
• the viscosity of a 4% aqueous solution of polyvinyl alcohol at 20°C is not particularly limited, but is, for example, preferably 300 mPa ⁇ s or less, more preferably 100 mPa ⁇ s or less, even more preferably 10 mPa ⁇ s or less, and even more preferably 5 mPa ⁇ s or less, and is preferably 1 mPa ⁇ s or more, and more preferably 2 mPa ⁇ s or more.
• the viscosity of a 4% aqueous solution of polyvinyl alcohol at 20°C can be measured, for example, by the method specified in JIS K6726.
• the content of component (B) relative to the total of 100 mass% of components (A) and (B) is not particularly limited, but is preferably 5 mass% or more, more preferably 8 mass% or more, even more preferably 15 mass% or more, and may be 20 mass% or more, and is preferably 60 mass% or less, more preferably 50 mass% or less, even more preferably 40 mass% or less, and may be 30 mass% or less.
• the content of component (B) is within this range, a resin composition having high transparency and excellent moldability can be obtained.
• the content of component (A) relative to the total of components (A) and (B) (100% by mass) is not particularly limited, but is preferably 40% by mass or more, more preferably 50% by mass or more, even more preferably 60% by mass or more, and may be 70% by mass or more, and is preferably 95% by mass or less, more preferably 92% by mass or less, and even more preferably 85% by mass or less, and may be 80% by mass or less.
• the content of component (A) is within this range, a resin composition having high transparency and excellent moldability can be obtained.
• the total content of component (A) and component (B) relative to 100% by mass of the total amount of the cellulose-based resin composition is not particularly limited, but is, for example, preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and even more preferably 95% by mass or more. It may be 100% by mass, but is preferably less than 99.8% by mass, more preferably 99.5% by mass or less, even more preferably 99% by mass or less, and even more preferably 98% by mass or less.
• the cellulose-based resin composition of the present disclosure may contain a plasticizer in one embodiment.
• the plasticizer is preferably a compound that is highly compatible with cellulose acetate of component (A) and does not become cloudy when mixed with cellulose acetate.
• the plasticizer is not particularly limited, but various additives used in ordinary thermoplastic resins can be used as long as they do not impair the effects of the present invention.
• the addition of a plasticizer can improve the processability of the resin composition and the elongation at break.
• a low molecular weight plasticizer is preferred as the plasticizer.
• plasticizer examples include phthalates such as dibutyl phthalate, diaryl phthalate, diethyl phthalate, dimethyl phthalate, di-2-methoxyethyl phthalate, ethylphthalyl-ethyl glycolate, and methylphthalyl-ethyl glycolate; tartarates such as dibutyl tartrate; adipic acids such as dioctyl adipate and diisononyl adipate; phosphates such as triethyl phosphate, triphenyl phosphate, and tricresyl phosphate; dibasic fatty acid esters such as dibutyl adipate, dioctyl adipate, dibutyl azelate, dioctyl azelate, and dioctyl sebacate; epoxidized vegetable oils such as epoxidized soybean oil and epoxidized linseed oil; castor oil and its derivative
• plasticizers such as dioctyl adipate, benzyl-2-butoxyethoxyethyl adipate, tricresyl phosphate, diphenylcresyl phosphate, and diphenyloctyl phosphate are particularly preferred.
• the cellulose resin composition contains a plasticizer
• its content is not particularly limited, but is preferably less than 15% by mass, more preferably 10% by mass or less, even more preferably 8% by mass or less, more preferably 5% by mass or less, even more preferably less than 5% by mass, and may be 0% by mass, but is preferably 1% by mass or more, and more preferably 3% by mass or more.
• the plasticizer content is within this range, a resin composition having high thermal stability and excellent fluidity and moldability can be provided.
• the plasticizer content is too high, the plasticizer may bleed out, or the thermal stability of the resin composition may be reduced due to the evaporation of the plasticizer.
• the resin composition of the present disclosure may contain a colorant as described below, but in embodiments that do not contain a colorant, it is preferable that the resin composition is highly transparent.
• the resin composition may be colorless or colored, but it is preferable that the resin composition is colorless and transparent. High transparency results in good color development when a colorant or the like is added, and a molded product with a high-quality appearance, i.e., excellent design, can be formed.
• the haze value of a molded article having a thickness of 0.3 mm and formed from a resin composition that does not contain a colorant is preferably 50% or less, more preferably 45% or less, even more preferably 40% or less, and even more preferably 30% or less.
• the cellulose-based resin composition may include a colorant, such as a black colorant.
• a preferred black colorant is, for example, carbon black.
• the average particle size of carbon black is preferably 1 to 20 nm, more preferably 5 to 20 nm, and even more preferably 8 to 18 nm.
• This average particle size is the arithmetic mean diameter of the carbon black particles determined by observing them under an electron microscope.
• the specific surface area of the carbon black is not limited, but from the viewpoint of jet blackness of the molded body, it is preferably 140 m 2 /g or more, more preferably 180 m 2 /g or more. From the viewpoint of dispersibility, carbon black with a specific surface area of 1000 m 2 /g or less, 700 m 2 /g or less, and even 500 m 2 /g or less can be used. Regarding the relationship between particle size and specific surface area, the smaller the particle size, the larger the specific surface area. From the viewpoint of brightness and appearance of the molded body and dispersibility of the particles, it is preferable to use carbon black with a BET specific surface area in the above range. This specific surface area is the BET specific surface area (JIS K6217) calculated by the S-BET formula from the nitrogen adsorption amount.
• this carbon black is preferably acidic, specifically preferably having a pH of 5 or less, more preferably having a pH of 4 or less, and even more preferably having a pH of 3.5 or less.
• acidic (low pH) carbon black By using such acidic (low pH) carbon black, the brightness of the molded body can be reduced.
• carbon black with a pH of preferably 2.5 to 4, more preferably 2.5 to 3.5, can be suitably used.
• This pH value was measured using a glass electrode pH meter on a mixture of carbon black and distilled water.
• the specific measurement method is as follows: 100 ml of boiled and degassed pure water is added to 10 g of sample, boiled on a hot plate for 15 minutes, cooled to room temperature, the supernatant liquid is removed, and the pH of the resulting muddy substance is measured using a glass electrode pH meter.
• the interaction or bonding between the acidic groups (e.g., carboxylic acid groups) on the surface of such acidic carbon black and the polar groups (e.g., hydroxyl groups) of cellulose acetate improves affinity, resulting in high dispersion of the carbon black and contributing to a decrease in brightness.
• the acidic groups e.g., carboxylic acid groups
• the polar groups e.g., hydroxyl groups
• colorants than the black colorant can be organic or inorganic pigments or dyes. Specific examples include metal oxides such as red iron oxide, iron(III) oxide, and chromium(III) oxide.
• the content of the colorant is not limited, but can be set in the range of, for example, 0.01 to 10 phr (meaning 0.01 to 10 parts by mass per 100 parts by mass of the total mass of the components other than the colorant in the cellulose-based resin composition. The same applies below to the standard for the content of the colorant) relative to the total mass of the components other than the colorant.
• the content of the colorant is preferably 0.05 phr or more, preferably 0.09 phr or more, and preferably 0.1 phr or more, relative to the total mass of the components other than the colorant. From the viewpoint of suppressing the amount of excess colorant while obtaining a sufficient coloring effect, 5 phr or less is preferable, 3 phr or less is more preferable, and 2 phr or less is even more preferable.
• the content of the colorant is not limited, but 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.
• the resin composition may contain, as other components, additives that are generally used in ordinary molding resin materials, provided that the purpose of this embodiment is not impaired.
• additives include phenolic or phosphorus-based antioxidants, light stabilizers, UV absorbers, antistatic agents, antibacterial and antifungal agents, fillers, flame retardants, etc.
• fillers can be added to the resin composition.
• strength and rigidity can be further improved.
• fillers include mineral particles (talc, mica, calcined silica, 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 carb
• fibrous fillers examples 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.), and metal fibers. These fillers can be used alone or in combination.
• the resin composition preferably has a low content of polylactic acid resin and aliphatic polyester (e.g., polybutylene succinate, polybutylene succinate adipate, polycaprolactone, polyhydroxybutyrate, polyhydroxybutyrate hexanate, etc.). If the content of these polylactic acid resins and aliphatic polyesters is high, the transparency when mixed with cellulose acetate decreases, making it difficult to obtain a molded product with excellent appearance. In one embodiment, the content of these components is preferably 3 mass% or less, more preferably 1 mass% or less, and even more preferably 0 mass%, relative to the total mass of the resin composition.
• polylactic acid resin and aliphatic polyester e.g., polybutylene succinate, polybutylene succinate adipate, polycaprolactone, polyhydroxybutyrate, polyhydroxybutyrate hexanate, etc.
• the resin composition preferably contains a small amount of polyvinyl alcohol having a high degree of saponification (preferably a degree of saponification of more than 40 mol%, more preferably a degree of saponification of 50 mol% or more). If the content of polyvinyl alcohol having a high degree of saponification is large, the composition may become cloudy when mixed with cellulose acetate.
• the content of polyvinyl alcohol having a degree of saponification of, for example, more than 40 mol% or 50 mol% is preferably 5 mass% or less, more preferably less than 5 mass%, more preferably 3 mass% or less, even more preferably 1 mass% or less, and even more preferably 0 mass%, relative to the total mass of the resin composition.
• the cellulose-based resin composition can be obtained by melt-mixing (preferably homogeneously mixing) the component (A) and the component (B) with other components as required using a conventional mixer.
• a mixer for example, a compounding device such as a tumbler mixer, a ribbon blender, a single-screw or multi-screw mixer extruder, a kneading kneader, or a kneading roll can be used.
• the mixture can be granulated into an appropriate shape as required, for example, pelletized using a pelletizer.
• the molded body formed using the cellulose resin composition of the present disclosure can be formed into a desired shape by a normal molding method, and the shape is not limited, and the thickness of the molded body is not limited. From the viewpoint of the strength of the molded body, for example, 0.5 mm or more is preferable, and 0.8 mm or more is more preferable. However, when a film or sheet is produced by extrusion molding, hot press molding, or the like, the thickness is preferably 0.01 mm or more, more preferably 0.1 mm or more, and may be 0.3 mm or more.
• the upper limit of the thickness of the molded body is not particularly limited and can be appropriately set according to the required shape and strength, but even if the thickness is set to, for example, 10 mm or less, or even 5 mm or less, a high-quality appearance can be obtained together with sufficient physical properties.
• the additives are distributed throughout the entire molded body (the entire body in any direction including the thickness direction), so that a high-quality appearance can be obtained in any shape without providing a coating or a decorative film.
• the cellulose-based resin composition disclosed herein can be molded into a molded article according to the intended purpose using conventional molding methods such as injection molding, injection compression molding, extrusion molding, and heat press molding.
• the molded articles formed using the cellulose-based resin composition according to the present disclosure have excellent design properties and can be applied to housings, exteriors, decorative panels, decorative films, etc., and can be used in place of parts used in, for example, electronic devices, home appliances, various containers, building materials, furniture, stationery, automobiles, and household goods. For example, they can be used in housings and exterior parts of electronic devices and home appliances, various storage cases, tableware, interior parts for building materials, interior materials for automobiles, and other everyday items.
• One aspect of this embodiment relates to products such as electronic devices, home appliances, automobiles, building materials, furniture, stationery, and household goods that contain a molded article formed using the resin composition of this embodiment.
• Applications for electronic devices or home appliances include housings for computers, landlines, mobile phones, smartphones, tablets, POS terminals, routers, projectors, speakers, lighting equipment, 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.
• Automotive applications include interior instrument panels, dashboards, cup holders, door trim, armrests, door handles, door locks, steering wheels, brake levers, ventilators, and shift levers.
• Building materials include interior wall materials, flooring, tiles, window frames, doorknobs, etc.
• Furniture applications include the exteriors of chests of drawers, bookshelves, tables, chairs, etc.
• Stationery applications include the exteriors of pens, pencil cases, book covers, scissors, cutters, etc.
• Applications for everyday items include eyeglass frames, cosmetic containers, product boxes, jewelry bodies and exteriors, decorative parts for clothing such as buttons, earphone exteriors, card bodies and exteriors, and business card trays.
• Sports-related items include golf tees and golf markers.
• Example A Examples A1 to A7, Comparative Examples A1 to A5>
• the constituent materials of the target cellulose resin composition the above-mentioned cellulose acetate (a1) and the resin additives (b1) to (b7) and (b1') to (b5') were prepared. Next, the constituent materials were thoroughly mixed by hand mixing in the blending ratio shown in Table 1 to obtain a mixture.
• the "blending ratio of resin additives" in Table 1 represents the blending ratio of the resin additives relative to the total of 100 mass% of the cellulose acetate (a1) and the resin additives. Note that the cellulose acetate, polylactic acid, and polybutylene succinate were previously dried at 80°C for 5 hours and then hand mixed.
• the obtained mixture was used to prepare a resin composition (pellets) according to the kneading method described later. Furthermore, the pellets were used to prepare a molded body (film) according to the molding method described later. The obtained film was evaluated for haze. The results are shown in Table 1.
• ⁇ Haze measurement> The film obtained by press molding was measured for haze (cloudiness), which is an index of transparency, using a haze meter (manufactured by Murakami Color Research Laboratory, product name: Haze Meter HM-65W type, conforming to JIS K 7136).
• the unit of the haze value is %. The smaller the haze value, the higher the transparency, and the better the appearance can be obtained when a colorant is used.
• Example B Examples B1 to B8, Comparative Examples B1 to B10> Pellets and a film were obtained in the same manner as in Example A, except that the types and blending ratios of the resin additives were changed as shown in Table 2. The haze of the obtained film was evaluated in the same manner as in Example A. The results are shown in Table 2.
• Example C1 Comparative Example C1>
• the constituent materials of the target cellulose-based resin composition the above-mentioned cellulose acetate (a1), the resin additive (b7) which is polyvinyl alcohol, and the plasticizer (d1) were prepared.
• the constituent materials were thoroughly mixed by hand mixing in the blending ratio shown in Table 3 to obtain a mixture.
• the blending ratio of polyvinyl alcohol and the blending ratio of plasticizer represent the blending ratio relative to the total of 100 mass% of cellulose acetate (a1), polyvinyl alcohol (b7), and plasticizer (d1).
• cellulose acetate was dried in advance at 80 ° C for 5 hours and then hand mixed.
• a resin composition (pellet) was prepared according to the same kneading method as in Example A.
• the obtained pellets were evaluated for melt flow rate (MFR) and thermal stability. The results are shown in Table 3.
• MFR melt flow rate
• the apparatus was filled with a nitrogen gas atmosphere, and the temperature was increased at 10°C/min. If the weight loss rate was less than 2%, the thermal stability was evaluated as ⁇ , if it was between 2% and 5%, it was evaluated as ⁇ , and if it was 5% or more, it was evaluated as ⁇ .
• Example C1 by including PVA, was able to reduce the plasticizer content and improve thermal stability (i.e., inhibit the volatilization of the plasticizer) compared to Comparative Example C1, while also achieving sufficient MFR (fluidity, moldability).
• a cellulose-based resin composition comprising:
• the acetyl substitution degree of the cellulose acetate (A) is 2.0 or more and 2.9 or less, The cellulose-based resin composition according to any one of the preceding appendices, wherein the polymer (B) is a polyvinyl alcohol obtained by partially saponifying polyvinyl acetate and having a degree of saponification of 1 mol % or more and 38 mol % or less.
• Appendix 16 The cellulose-based resin composition according to any one of the preceding appendices, wherein a molded article having a thickness of 0.3 mm formed from the cellulose-based resin composition containing no colorant has a haze value of 50% or less.
• Appendix 17 A molded article formed using the cellulose-based resin composition according to any one of the preceding appendices.

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• 2023
  • 2023-11-14 JP JP2024558885A patent/JPWO2024106419A1/ja active Pending
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