Cellulose-based material, molding material, production method of molded body and cellulose-based material

Abstract

To provide: a cellulose-based material and a molding material capable of being appropriately used for production of a molded body which is excellent in strength and impact resistance and of which the undesired discoloration, especially the yellow discoloration is appropriately prevented; the molded body which is excellent in strength and impact resistance and of which the undesired discoloration, especially the yellow discoloration is appropriately prevented; and a production method of the cellulose-based material with which the cellulose-based material capable of being appropriately used for production of the molded body which is excellent in strength and impact resistance and of which the undesired discoloration, especially the yellow discoloration is appropriately prevented can be appropriately produced.SOLUTION: A cellulose-based material of the invention contains a cellulose derivative formed by esterifying a hydroxy group of cellulose, of which the yellowness is less than 1.0 and the content of volatile organic compounds is less than 5 mass%.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a cellulosic material, a molding material, a molded body, and a method for producing a cellulosic material. [Background technology]

[0002] As a measure to combat oil depletion and global warming, attempts are being considered to replace conventional plastic materials with molding materials made from cellulose, a plant-derived, abundant natural material.

[0003] For example, a cellulose derivative has been proposed which has a short-chain organic group introduced by esterification in place of a hydrogen atom of a hydroxy group of cellulose and a long-chain organic group introduced by esterification in place of a hydrogen atom of the hydroxy group of cellulose, the solubility in chloroform being 10 mass% or less, the short-chain organic group being a short-chain acyl group having 2 to 4 carbon atoms, and the long-chain organic group being a long-chain acyl group having 5 to 48 carbon atoms or a group derived from a cardanol derivative (see Patent Document 1).

[0004] In addition, a technique has been proposed in which a cellulose derivative having a hydroxyl group is subjected to ring-opening graft polymerization of a cyclic ester in the presence of a ring-opening polymerization catalyst, to obtain a grafted cellulose derivative, and the resulting grafted cellulose derivative is subjected to a catalytic reaction with a peroxide (see Patent Document 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2018-59125 [Patent Document 2] Japanese Patent Application Laid-Open No. 2000-319401 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the technology described in Patent Document 1, by-products generated in the process of esterifying hydroxy groups discolor due to the heat during the reaction and remain in the derivative, causing yellowing. In addition, in the technology described in Patent Document 2, although decolorization is possible by reaction with peroxide, there is a problem in that the strength and impact resistance of molded articles produced using cellulose-based materials are reduced.

[0007] That is, conventionally, there has been a problem in that it has not been possible to simultaneously prevent discoloration, particularly yellowing, of cellulosic materials and ensure the strength and impact resistance of molded articles produced using the cellulosic materials. [Means for solving the problem]

[0008] The present invention has been made to solve the above-mentioned problems, and can be realized as the following application examples.

[0009] A cellulose-based material according to an application example of the present invention is a cellulose-based material containing a cellulose derivative in which a hydroxy group of cellulose is esterified, Yellowness index is less than 1.0, The content of volatile organic compounds is less than 5% by mass.

[0010] Further, the molding material according to the application example of the present invention comprises cellulose fibers, and a cellulosic material according to an application example of the present invention.

[0011] Further, the molded article according to the application example of the present invention comprises cellulose fibers and The cellulosic material according to the application example of the present invention is composed of a material containing the cellulosic material.

[0012] Furthermore, a method for producing a cellulose-based material according to an application example of the present invention is a method for producing a cellulose-based material containing a cellulose derivative in which a hydroxy group of cellulose is esterified, the method comprising the steps of: an esterification step of esterifying the cellulose; and a washing step of washing the composition obtained in the esterification step with an acidic aqueous solution or water at 50°C or higher. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a table summarizing the liquids used in the cleaning steps for Examples A1 to A7 and Comparative Examples A1 and A2. [Figure 2] FIG. 2 is a table summarizing the compositions of the molding materials according to Examples B1 to B11 and Comparative Examples B1 and B2, and the evaluation results of the molded articles according to Examples B1 to B11 and Comparative Examples B1 and B2. DETAILED DESCRIPTION OF THE INVENTION

[0014] Preferred embodiments of the present invention will be described in detail below. [1] Cellulose-based materials First, the cellulosic material of the present invention will be described.

[0015] The cellulosic material of the present invention contains a cellulose derivative in which the hydroxyl groups of cellulose are esterified, and has a yellowness index of less than 1.0 and a volatile organic compound content of less than 5% by mass.

[0016] With this configuration, it is possible to provide a cellulose-based material that is excellent in strength and impact resistance and can be suitably used to produce molded articles that are suitably prevented from undesired discoloration, particularly yellowing.

[0017] On the other hand, if the above conditions are not met, satisfactory results will not be obtained. For example, if the yellowness of the cellulose-based material is too high, the molded article produced using the cellulose-based material is likely to suffer from undesired discoloration (particularly yellowing).

[0018] Furthermore, if the content of volatile organic compounds in the cellulosic material is too high, the molded article produced using the cellulosic material is likely to suffer from undesired discoloration, particularly yellowing, and the molded article will also have poor light resistance.

[0019] In the present invention, yellowness refers to the yellowness index (YI) determined in accordance with JIS K 7373. For measuring the yellowness, for example, a spectrophotometer SQ7700 (manufactured by Nippon Denshoku Industries Co., Ltd.) can be used.

[0020] In the present invention, the content of volatile organic compounds refers to a value determined by the following measurement: Approximately 5 g of the target cellulosic material is weighed out, and the volatile organic compounds are removed in a vacuum dryer under conditions of a temperature of 80°C, a vacuum degree of 50 Pa, and a treatment time of 5 hours. Thereafter, the mass of the cellulosic material is weighed again to determine the rate of mass loss, and this rate of loss is regarded as the content of volatile organic compounds.

[0021] As mentioned above, the yellowness index of the cellulosic material of the present invention may be less than 1.0, preferably less than 0.8, more preferably less than 0.7, and even more preferably less than 0.5. This makes the above-mentioned effects more pronounced.

[0022] As mentioned above, the content of volatile organic compounds in the cellulosic material of the present invention may be less than 5% by mass, preferably less than 3% by mass, and more preferably less than 1% by mass. This makes the above-mentioned effects more pronounced.

[0023] The content of nitrogen atom-containing organic impurities in the cellulosic material of the present invention is preferably 1000 ppm or less, more preferably 700 ppm or less, and even more preferably 500 ppm or less.

[0024] This makes it possible to provide the cellulosic material of the present invention and a molded article produced using the cellulosic material of the present invention with better light resistance.

[0025] The cellulose-based material of the present invention contains a cellulose derivative in which the hydroxy groups of cellulose are esterified.

[0026] The cellulose derivative may have a structure in which the hydroxyl groups of cellulose are esterified, in other words, a structure in which some of the hydrogen atoms constituting the hydroxyl groups of cellulose are substituted with R(C=O)- (where R is a monovalent atomic group containing a carbon atom), but preferably satisfies the following conditions:

[0027] That is, the cellulose derivative preferably has a structure in which at least a portion of the hydroxyl groups of cellulose are substituted with an ester group having 2 to 48 carbon atoms (R(C=O)- having 1 to 47 carbon atoms) or a group derived from a cardanol derivative.

[0028] This makes it possible to improve the affinity and compatibility of the cellulose derivative with cellulose fibers, thereby improving the strength and impact resistance of molded bodies produced using the molding material described below, and improving the moldability of the molded bodies during production.

[0029] As described above, the number of carbon atoms in the ester group is preferably 2 or more and 48 or less, more preferably 4 or more and 40 or less, and even more preferably 8 or more and 30 or less. This makes the above-mentioned effects more pronounced.

[0030] Examples of groups derived from cardanol derivatives include groups having a carboxyl group obtained by using hydrogenated cardanol (manufactured by ACROS Organics, mn-pentadecylphenol) as a raw material and reacting its phenolic hydroxyl group with monochloroacetic acid.

[0031] The DS value of the cellulose derivative, i.e., the degree of substitution, which is the value obtained by dividing the number of hydrogen atoms of all hydroxyl groups in cellulose that are substituted with substituents by the number of glucose molecules that constitute the cellulose, is preferably 2.0 or more and 3.0 or less, and more preferably 2.1 or more and 2.9 or less.

[0032] This makes it possible to improve the affinity and compatibility of the cellulose derivative with cellulose fibers, thereby improving the strength and impact resistance of molded bodies produced using the molding material described below, and improving the moldability of the molded bodies during production.

[0033] [2] Manufacturing methods for cellulosic materials Next, the method for producing the cellulosic material of the present invention will be described.

[0034] The method for producing a cellulose-based material of the present invention is a method for producing a cellulose-based material containing a cellulose derivative in which the hydroxy groups of cellulose are esterified, and includes an esterification step of esterifying cellulose and a washing step of washing the composition obtained in the esterification step with an acidic aqueous solution or water at 50°C or higher.

[0035] With this configuration, it is possible to provide a method for producing the above-mentioned cellulose-based material, i.e., a cellulose-based material that is excellent in strength and impact resistance and can be suitably used for producing molded articles that are suitably prevented from undesired discoloration, particularly yellowing. In particular, the content of volatile organic compounds and the content of nitrogen-containing organic impurities in the produced cellulose-based material can be sufficiently low, thereby achieving the above-mentioned effects.

[0036] [2-1] Esterification process In the esterification step, at least a portion of the hydroxyl groups of the cellulose is esterified.

[0037] For the esterification, a carboxylic acid, an acid anhydride, an acid halide, or the like corresponding to the ester group to be introduced can be used. In this step, a catalyst such as an acid catalyst may be used.

[0038] Examples of solvents that can be used in this step include cyclic ethers (dioxane, tetrahydrofuran, dioxolane, etc.); in addition to the above-mentioned cyclic ethers, acyclic ethers having multiple ether structural moieties such as 1,2-dimethoxyethane and diethylene glycol dimethyl ether; ethers having aryl groups such as methyl phenyl ether and diphenyl ether; amides (N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, etc.); ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc.); esters (methyl formate, methyl acetate, ethyl acetate, butyl acetate, methyl cellosolve acetate, etc.); polar halogenated hydrocarbons (chloroform, methylene chloride, dichloroethane, propylene chloride, tetrachloroethane, etc.); and the like. One or more solvents selected from these can be used in combination.

[0039] The reaction temperature in this step is not particularly limited, but can be set to 40°C or higher and 100°C or lower.

[0040] [2-2] Cleaning process In the washing step, the composition obtained in the above-mentioned esterification step is washed with an acidic aqueous solution or water at 50° C. or higher.

[0041] This allows for the efficient removal of by-products and volatile organic compounds produced in the esterification process, etc., and provides a cellulose-based material that is excellent in strength and impact resistance and can be suitably used to produce molded articles that are suitably prevented from undesired discoloration, particularly yellowing.

[0042] Examples of the acidic aqueous solution include hydrochloric acid, nitric acid, and sulfuric acid. One or more selected from these may be used in combination, with nitric acid being particularly preferred.

[0043] The pH of the acidic aqueous solution at 25° C. is preferably 0 or more and 6.0 or less, and more preferably 0 or more and 3.0 or less.

[0044] When an acidic aqueous solution is used in this step, the temperature of the acidic aqueous solution in this step is preferably 0°C or higher and 60°C or lower, more preferably 5°C or higher and 50°C or lower, and even more preferably 10°C or higher and 40°C or lower.

[0045] When water is used in this step, the temperature of the water may be 50°C or higher, preferably 50°C or higher and 90°C or lower, and more preferably 50°C or higher and 80°C or lower.

[0046] The number of washing treatments in this step is not particularly limited, and washing may be repeated multiple times. In this step, washing with an acidic aqueous solution and washing with water at a temperature of 50° C. or higher may be performed in combination. In this case, the order of these treatments is not particularly limited.

[0047] [2-3] Other processes The method for producing a cellulosic material of the present invention may include the above-mentioned esterification step and washing step, but may further include other steps. Such processes include a pre-processing process, an intermediate processing process, and a post-processing process.

[0048] In the method for producing a cellulose-based material of the present invention, cellulose may be subjected to other reactions in addition to the esterification reaction. Examples of such reactions include etherification and partial hydrolysis. Such reactions may be carried out before or after the esterification step.

[0049] [3] Molding material Next, the molding material of the present invention will be described.

[0050] The molding material of the present invention contains cellulose fibers and the above-described cellulosic material of the present invention.

[0051] With this configuration, it is possible to provide a molding material that is excellent in strength and impact resistance and can be suitably used to produce molded articles that are suitably prevented from undesired discoloration, particularly yellowing.

[0052] The reason for such excellent effects is believed to be as follows: In other words, the composition contains cellulose, which has high theoretical strength and excellent shape stability, as well as a cellulose derivative that has excellent compatibility and affinity with cellulose fibers and excellent heat resistance and toughness, and the content of by-products generated during the synthesis of the cellulose derivative is sufficiently low, thereby preventing or suppressing the functions of the cellulose fibers and the cellulose derivative from canceling each other out, allowing these components to fully exhibit their functions. As a result, the excellent effects described above are believed to be obtained.

[0053] Furthermore, the inclusion of cellulose fiber, which is a plant-derived, abundant natural material, makes it possible to appropriately address environmental issues and conserve buried resources, etc., and is also advantageous from the viewpoints of stable supply of molding materials and molded articles produced using the same, cost reduction, etc. Furthermore, cellulose fiber is a component that is contained in large amounts not only in virgin pulp but also in waste paper, used cloth, etc., and is therefore advantageous from the viewpoint of promoting effective reuse of resources.

[0054] Furthermore, the cellulose derivatives can be suitably obtained from the above-mentioned cellulose as a raw material and are generally components with excellent biodegradability, which allows the molding material as a whole and the molded article produced using the molding material as a whole to suitably address environmental issues, etc.

[0055] [3-1] Cellulose fiber The molding material of the present invention contains cellulose fibers. Cellulose fiber is the main component of the molding material of the present invention, and is a component that greatly contributes to maintaining the shape of the molded body produced using the molding material of the present invention, as well as having a significant impact on the properties of the molded body, such as its strength.

[0056] Cellulose is a naturally occurring material derived from plants and is abundant in nature. Therefore, the use of cellulose fibers can effectively address environmental issues and conserve buried resources, and is also preferable from the viewpoints of stable supply of molding materials and molded articles produced using the same, cost reduction, etc. Furthermore, among various fibers, cellulose fibers have particularly high theoretical strength, and are advantageous from the viewpoint of improving the strength of molded articles.

[0057] As the cellulose fiber, virgin pulp may be used, or recycled waste paper, waste cloth, etc. may be used.

[0058] Cellulose fibers are generally composed mainly of cellulose, but may contain components other than cellulose, such as hemicellulose and lignin.

[0059] Furthermore, the cellulose fibers used may be those that have been subjected to a treatment such as bleaching. Examples of cellulose fibers include cotton, hemp, rayon, and cupra.

[0060] The content of cellulose fibers in the molding material is not particularly limited, but is preferably 40% by mass or more and 90% by mass or less, more preferably 45% by mass or more and 85% by mass or less, and even more preferably 50% by mass or more and 80% by mass or less.

[0061] This results in the material containing a larger amount of cellulose fiber, which is a plant-derived, abundant natural material, which can more appropriately address environmental issues and conserve buried resources, and is more preferable from the standpoint of stable supply of molding materials and molded articles produced using them, cost reduction, etc. It is also more preferable from the standpoint of improving the strength of molded articles, and the molding material will have better plasticity and moldability.

[0062] The average length of the cellulose fibers is not particularly limited, but is preferably 500 μm or less, more preferably 1 μm or more and 400 μm or less, and even more preferably 1 μm or more and 50 μm or less.

[0063] This improves the affinity and compatibility of the cellulose fibers with the cellulose derivative, thereby improving the shape stability and strength of the molded article produced using the molding material. Furthermore, dust generation in the molded article produced using the molding material can be more effectively prevented and suppressed. Furthermore, the occurrence of undesired irregularities on the surface of the molded article produced using the molding material can be more effectively prevented. The fiber length of the cellulose fibers is determined by a method in accordance with ISO 16065-2:2007.

[0064] The average thickness of the cellulose fibers is not particularly limited, but is preferably 0.1 μm or more and 100 μm or less, and more preferably 0.2 μm or more and 30 μm or less.

[0065] This makes it possible to improve the shape stability, strength, etc. of a molded article produced using the molding material, and also makes it possible to more effectively prevent the occurrence of undesired irregularities on the surface of a molded article produced using the molding material.

[0066] The average aspect ratio of the cellulose fibers, that is, the average length to the average thickness, is not particularly limited, but is preferably 10 or more and 1,000 or less, and more preferably 15 or more and 100 or less.

[0067] This makes it possible to improve the shape stability, strength, etc. of a molded article produced using the molding material. Also, dust generation in a molded article produced using the molding material can be more effectively prevented or suppressed. Also, it is possible to more effectively prevent the occurrence of undesired irregularities on the surface of a molded article produced using the molding material.

[0068] [3-2] Cellulose derivatives The molding material of the present invention contains the cellulose derivative, that is, a cellulose derivative in which the hydroxyl groups of cellulose are esterified.

[0069] The cellulose derivative preferably satisfies the condition described in [1] above.

[0070] The content of the cellulose derivative in the molding material is preferably 10% by mass or more and 60% by mass or less, more preferably 15% by mass or more and 55% by mass or less, and even more preferably 20% by mass or more and 50% by mass or less.

[0071] This makes it possible to improve the strength and impact resistance of a molded article produced using the molding material, and to improve the moldability during production of the molded article.

[0072] In particular, when the content of the cellulose fiber and the content of the cellulose derivative in the molding material both satisfy the above-mentioned conditions, the above-mentioned effects are more significantly exhibited.

[0073] When the content of cellulose fiber in the molding material is XC [% by mass] and the content of the cellulose derivative is XD1 [% by mass], it is preferable to satisfy the relationship 0.10≦XD1 / XC≦0.80, more preferably the relationship 0.15≦XD1 / XC≦0.75, and even more preferably the relationship 0.20≦XD1 / XC≦0.70.

[0074] This makes it possible to improve the strength and impact resistance of a molded article produced using the molding material, and to improve the moldability during production of the molded article.

[0075] [3-4] Flame retardants The molding material of the present invention may further contain a flame retardant. This makes it possible to improve the flame retardancy of a molded article produced using the molding material of the present invention.

[0076] Examples of the flame retardant include bromine-based flame retardants, chlorine-based flame retardants, phosphorus-containing flame retardants, silicon-containing flame retardants, nitrogen compound-based flame retardants, and inorganic flame retardants.

[0077] Among these, phosphorus-containing flame retardants and silicon-containing flame retardants are preferred because they do not generate hydrogen halides through thermal decomposition during mixing / kneading with other components or during molding processing, which may corrode processing machinery or molds or worsen the working environment, and they are less likely to have adverse effects on the environment through the release of halogens or the generation of dioxins and other compounds through decomposition when incinerated.

[0078] Examples of phosphorus-containing flame retardants include organic phosphorus compounds such as phosphate esters, phosphate condensed esters, and polyphosphates.

[0079] Examples of phosphate esters include trimethyl phosphate, triethyl phosphate, tributyl phosphate, tri(2-ethylhexyl) phosphate, tributoxyethyl phosphate, triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, tris(isopropylphenyl) phosphate, tris(phenylphenyl) phosphate, trinaphthyl phosphate, cresyl diphenyl phosphate, xylenyl diphenyl phosphate, diphenyl(2-ethylhexyl) phosphate, di(isopropylphenyl) phosphate, Examples of suitable acryloyloxyethyl phosphate include diphenyl-2-acryloyloxyethyl phosphate, diphenyl-2-methacryloyloxyethyl phosphate, diphenyl-2-acryloyloxyethyl phosphate, diphenyl-2-methacryloyloxyethyl phosphate, melamine phosphate, dimelamine phosphate, melamine pyrophosphate, triphenylphosphine oxide, tricresylphosphine oxide, diphenyl methanephosphonate, and diethyl phenylphosphonate.

[0080] Examples of the phosphoric acid condensed ester include aromatic phosphoric acid condensed esters such as resorcinol polyphenyl phosphate, resorcinol poly(di-2,6-xylyl) phosphate, bisphenol A polycresyl phosphate, hydroquinone poly(2,6-xylyl) phosphate, and condensates thereof.

[0081] Further examples include polyphosphates formed from salts of phosphoric acid or polyphosphoric acid with metals of Groups 1 to 14 of the periodic table, ammonia, aliphatic amines, and aromatic amines. Representative polyphosphate salts include metal salts such as lithium salt, sodium salt, calcium salt, barium salt, iron (II) salt, iron (III) salt, and aluminum salt; aliphatic amine salts such as methylamine salt, ethylamine salt, diethylamine salt, triethylamine salt, ethylenediamine salt, and piperazine salt; and aromatic amine salts such as pyridine salt and triazine.

[0082] In addition to the above, examples include halogen-containing phosphate esters such as trischloroethyl phosphate, trisdichloropropyl phosphate, and tris(β-chloropropyl) phosphate, phosphazene compounds having a structure in which a phosphorus atom and a nitrogen atom are linked by a double bond, and phosphate ester amides.

[0083] Examples of silicon-containing flame retardants include organosilicon compounds with a two-dimensional or three-dimensional structure, polydimethylsiloxanes, and polydimethylsiloxanes in which the methyl groups on the side chains or ends are substituted or modified with hydrogen atoms, substituted or unsubstituted aliphatic hydrocarbon groups, or aromatic hydrocarbon groups, so-called silicone oils or modified silicone oils.

[0084] Examples of substituted or unsubstituted aliphatic hydrocarbon groups and aromatic hydrocarbon groups include alkyl groups, cycloalkyl groups, phenyl groups, benzyl groups, amino groups, epoxy groups, polyether groups, carboxyl groups, mercapto groups, chloroalkyl groups, alkyl higher alcohol ester groups, alcohol groups, aralkyl groups, vinyl groups, and trifluoromethyl groups.

[0085] Furthermore, as flame retardants other than the phosphorus-containing flame retardants and silicon-containing flame retardants, for example, inorganic flame retardants such as magnesium hydroxide, aluminum hydroxide, antimony trioxide, antimony pentoxide, sodium antimonate, zinc hydroxystannate, zinc stannate, metastannic acid, tin oxide, tin oxide salts, zinc sulfate, zinc oxide, ferrous oxide, ferric oxide, stannous oxide, stannic oxide, zinc borate, ammonium borate, ammonium octamolybdate, metal salts of tungstic acid, composite oxides of tungsten and metalloid, ammonium sulfamate, ammonium bromide, zirconium-based compounds, guanidine-based compounds, fluorine-based compounds, graphite, and expandable graphite can be used.

[0086] When the molding material contains a flame retardant, the content of the flame retardant can be 1 part by mass or more and 30 parts by mass or less when the total content of the cellulose fiber and the cellulose derivative is 100 parts by mass.

[0087] This makes it possible to more effectively exhibit the effects of the present invention described above, while also making it possible to improve the flame retardancy of a molded article produced using the molding material of the present invention.

[0088] [3-5] Antioxidants The molding material of the present invention may further contain an antioxidant. This improves the resin's stability against heating during the kneading and molding processes.

[0089] Examples of antioxidants include phosphorus-based antioxidants and hindered phenol-based antioxidants (e.g., "Irganox 1010," "Irganox 1076," and "Irganox 3114" manufactured by Ciba Specialty Chemicals, and "Sumilizer GP" manufactured by Sumitomo Chemical Co., Ltd.).

[0090] When the molding material contains an antioxidant, the content of the antioxidant can be 0.05 parts by mass or more and 2.0 parts by mass or less when the total content of the cellulose fiber and the cellulose derivative is 100 parts by mass.

[0091] [3-6] Other ingredients The molding material of the present invention may contain components other than those described above. Hereinafter, in this section, such components will also be referred to as "other components."

[0092] Examples of other components include colorants, insect repellents, mildew inhibitors, antibacterial agents, antistatic agents, flame retardant assistants, ultraviolet absorbers, aggregation inhibitors, release agents, processing aids, anti-drip agents, cellulose derivatives other than the above-mentioned cellulose derivatives, resin materials, and plasticizers.

[0093] However, the content of other components in the molding material of the present invention is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass or less.

[0094] [4] Manufacturing method of molding material Next, a method for producing the molding material of the present invention will be described. The molding material of the present invention can be produced, for example, by mixing the above-mentioned components. In this case, the timing of mixing the components may be the same or different.

[0095] The molding material of the present invention may be produced by kneading the above-mentioned components, for example. The components can be kneaded using, for example, a single-screw kneader, a twin-screw kneader, a multi-screw kneader, a mixer, or a roll Banbury mixer.

[0096] The strand-shaped molding material obtained by kneading may be pelletized using a pelletizer such as a strand type or a watering hot cut type to form a pellet-shaped molding material.

[0097] The following method may also be used as a method for producing a molding material. That is, a kneaded mixture of the above-mentioned components may be formed into a sheet, and then cut into a desired shape using, for example, a shredder to produce pellets of molding material. The method for forming the kneaded mixture into a sheet is not particularly limited, but examples include a method in which the kneaded mixture is first deposited in air to form a sheet-like deposit, the deposit is compressed using a calendar device to remove air and increase density, and then heated in a heating furnace without contact, and then hot-pressed using a heat press. The shape and size of the pellets obtained by cutting are not particularly limited, but they can be, for example, approximately rectangular parallelepipeds with a side length of 2 mm to 5 mm.

[0098] The cellulose fibers used in the production of the molding material of the present invention may be those that have been previously subjected to a defibration treatment. In particular, cellulose fiber sources containing cellulose fibers, such as waste paper, may be defibrated.

[0099] [5] Molded body Next, the molded article of the present invention will be described.

[0100] The molded article of the present invention is made of a material containing cellulose fibers and the above-described cellulosic material of the present invention.

[0101] This makes it possible to provide a molded article that is excellent in strength and impact resistance and is suitably prevented from undesired discoloration, particularly yellowing.

[0102] Furthermore, the inclusion of cellulose fibers, which are naturally abundant and plant-derived materials, makes it possible to appropriately address environmental issues and conserve buried resources, and is also advantageous from the viewpoints of stable supply of molded products, cost reduction, etc. Furthermore, cellulose fibers are a component that is contained in large amounts not only in virgin pulp but also in waste paper, used cloth, etc., and is therefore advantageous from the viewpoint of promoting effective reuse of resources.

[0103] Furthermore, the cellulose derivatives can be suitably obtained from the above-mentioned cellulose as a raw material and are generally components with excellent biodegradability, which allows the molded article as a whole to suitably address environmental issues, etc.

[0104] The molded article of the present invention can be suitably produced by using the molding material of the present invention described above.

[0105] Each component constituting the molded body preferably satisfies the conditions described above in [3-1] to [3-6].

[0106] The content of cellulose fibers in the molded body is not particularly limited, but is preferably 40% by mass or more and 90% by mass or less, more preferably 45% by mass or more and 85% by mass or less, and even more preferably 50% by mass or more and 80% by mass or less.

[0107] This results in the material containing more cellulose fiber, which is a plant-derived and abundant natural material, which can more appropriately address environmental issues and conserve buried resources, and is more preferable from the standpoint of stable supply of molded bodies, cost reduction, etc., and also from the standpoint of improving the strength of molded bodies.

[0108] The content of the cellulose derivative in the molded body is preferably 10% by mass or more and 60% by mass or less, more preferably 15% by mass or more and 55% by mass or less, and even more preferably 20% by mass or more and 50% by mass or less. This allows the molded article to have better strength and impact resistance.

[0109] In particular, when the content of the cellulose fiber and the content of the cellulose derivative in the molded article both satisfy the above-mentioned conditions, the above-mentioned effects are more significantly exhibited.

[0110] When the content of cellulose fiber in the molded body is XC [% by mass] and the content of the cellulose derivative is XD1 [% by mass], it is preferable to satisfy the relationship 0.10≦XD1 / XC≦0.80, more preferably the relationship 0.15≦XD1 / XC≦0.75, and even more preferably the relationship 0.20≦XD1 / XC≦0.70. This allows the molded article to have better strength and impact resistance.

[0111] The yellowness index of the molded article of the present invention is preferably less than 1.0, more preferably less than 0.8, even more preferably less than 0.7, and most preferably less than 0.5. This makes the above-mentioned effects more pronounced.

[0112] The shape of the molded product is not particularly limited, and may be any shape, such as a sheet, a block, a sphere, or a three-dimensional shape.

[0113] The molded article may be used for any purpose, and examples thereof include various housings such as housings for printers, ink cartridges, various containers, and the like.

[0114] In particular, the molded body of the present invention has a high affinity between the cellulose fibers and the cellulose derivative, and dust generation is effectively prevented, making it suitable for use in ink cartridges and the like, where dust generation is a particular problem.

[0115] [6] Manufacturing method for molded body Next, a method for producing the molded article of the present invention will be described.

[0116] The molded article of the present invention can be produced, for example, by a method including a molding material preparation step of preparing the molding material of the present invention and a heat molding step of heat molding the molding material.

[0117] This makes it possible to suitably produce a molded article that is excellent in strength and impact resistance and is suitably prevented from undesired discoloration, particularly yellowing.

[0118] Furthermore, the inclusion of cellulose fibers, which are naturally abundant and plant-derived materials, makes it possible to appropriately address environmental issues and conserve buried resources, and is also advantageous from the viewpoints of stable supply of molded products, cost reduction, etc. Furthermore, cellulose fibers are a component that is contained in large amounts not only in virgin pulp but also in waste paper, used cloth, etc., and is therefore advantageous from the viewpoint of promoting effective reuse of resources.

[0119] Furthermore, the cellulose derivatives can be suitably obtained from the above-mentioned cellulose as a raw material and are generally components with excellent biodegradability, which allows the molded article as a whole to suitably address environmental issues, etc.

[0120] [6-1] Molding material preparation process In the molding material preparation step, the molding material of the present invention described above is prepared. In this step, for example, the molding material of the present invention may be prepared by mixing a plurality of different compositions.

[0121] [6-2] Heat forming process In the heat molding step, the molding material of the present invention is heat molded.

[0122] The heating temperature in this step is not particularly limited, but is preferably 170°C or higher and 220°C or lower, and more preferably 180°C or higher and 200°C or lower.

[0123] This effectively prevents undesired denaturation, deterioration, etc. of the constituent components of the molding material, while improving the moldability in this process, and more reliably improving the dimensional accuracy, mechanical strength, etc. of the molded body produced.

[0124] Examples of molding methods in the heat molding step include injection molding, press molding, extrusion molding, etc. Also, a molding method using a so-called 3D printer can be applied.

[0125] [6-3] Other processes The method for producing a molded article of the present invention may further include other steps in addition to the molding material preparation step and the heat molding step described above. Such steps include a pre-treatment step, an intermediate treatment step, and a post-treatment step.

[0126] Examples of intermediate treatment steps include a step of mixing the molding material of the present invention with a composition other than the molding material of the present invention, and a step of mixing a plurality of types of molding materials of the present invention.

[0127] Examples of post-processing processes include processes in which the molded product obtained in the heat molding process is subjected to chemical treatment, mechanical processing, etc., and an assembly process in which the molded product obtained in the heat molding process is assembled with other components.

[0128] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these.

[0129] For example, the molded article of the present invention may be any article made of a material containing the molding material of the present invention, and is not limited to articles produced by the above-mentioned method. [Example]

[0130] Next, specific examples of the present invention will be described. [7] Production of cellulosic materials

[0131] (Example A1) In this example, the cellulose derivative was produced by the following activation step, esterification step, and washing step.

[0132] <Activation process> First, 10 g (mass excluding adsorbed water) of cellulose (manufactured by Nippon Paper Chemicals Co., Ltd., product name: KC Flock, brand: W-50GK) was dispersed in 150 mL of pure water to obtain a dispersion.

[0133] This dispersion was stirred for 15 minutes and then subjected to suction filtration for 5 minutes. The solids obtained by suction filtration were dispersed in 150 mL of acetic acid, stirred for 15 minutes, and then subjected to suction filtration for 5 minutes to remove the acetic acid. This process of dispersion in acetic acid and removal of the acetic acid was repeated twice to obtain activated cellulose.

[0134] <Esterification step> To the activated cellulose obtained as described above, 150 mL of toluene, 80 mL of acetic acid, 80 μL of perchloric acid, and 5 g of dimethylaminopyridine were added, followed by the addition of 80 mL of acetic anhydride as an acid anhydride, and the mixture was stirred for 24 hours at 90° C. After 24 hours, the reaction mixture was filtered by suction filtration to obtain a crude product as a solid.

[0135] <Cleaning process> The crude product obtained in the esterification step was immersed in 100 mL of 1% by volume nitric acid at 20° C. for 100 minutes. After stirring for 100 minutes, the solid content was filtered off by suction filtration and washed with 200 mL of pure water at 20° C. The solid was then dried under reduced pressure to obtain a cellulosic material as a solid.

[0136] (Examples A2 to A6) Cellulosic materials were produced in the same manner as in Example A1, except that the liquid used in the washing step was changed to that shown in Figure 1. In Examples A2 to A4 and A6, the materials were immersed in 100 mL of nitric acid of a predetermined concentration at 20°C for 100 minutes, and then washed with 200 mL of pure water at a predetermined temperature.

[0137] (Example A7) An activation step was carried out in the same manner as in Example 1 to obtain activated cellulose.

[0138] Next, the acid anhydride-modified hydrogenated cardanol was reacted to produce a cellulose derivative. More specifically, 1.50 g of activated cellulose was dried and dispersed in 20 mL of dehydrated dioxane. Next, a dioxane solution of 185 mg (1.5 mmol) of dimethylaminopyridine (DMAP) dissolved in 5 mL of dehydrated dioxane was added to this dispersion. Furthermore, a dioxane solution of 9.7 g (12 mmol) of the synthesized acid anhydride-modified hydrogenated cardanol dissolved in 20 mL of dehydrated dioxane was added. The synthesis method of the acid anhydride-modified hydrogenated cardanol will be described in detail later. Next, after stirring at 90°C for 5 hours, 25 mL of the stirred suspension was removed and filtered under reduced pressure. After filtering, the mixture was immersed in 100 mL of 1% nitric acid at 20°C for 100 minutes. After stirring for 100 minutes, the solids were filtered off by suction filtration and washed with 200 mL of pure water at 20°C. Thereafter, the mixture was dried under reduced pressure to obtain a cellulosic material as a solid.

[0139] The synthesis method of acid anhydride-modified hydrogenated cardanol is as follows. Hydrogenated cardanol (manufactured by ACROS Organics, mn-pentadecylphenol), in which the unsaturated bonds in the linear hydrocarbon portion of cardanol were hydrogenated, was used as a raw material. The phenolic hydroxyl groups were reacted with monochloroacetic acid to provide carboxyl groups, yielding carboxylated hydrogenated cardanol. Specifically, carboxylated hydrogenated cardanol was produced as follows. First, 80 g (0.26 mol) of hydrogenated cardanol was dissolved in 120 mL of methanol, and an aqueous solution of 64 g (1.6 mol) of sodium hydroxide dissolved in 40 mL of distilled water was added to the solution. Subsequently, a solution of 66 g (0.70 mol) of monochloroacetic acid (manufactured by Kanto Chemical Co., Inc.) dissolved in 50 mL of methanol was added dropwise at room temperature. After the dropwise addition was completed, the mixture was refluxed at 73°C for 4 hours while stirring. After cooling to room temperature, the reaction solution was acidified with dilute hydrochloric acid to a pH of 1, and 250 mL of methanol, 500 mL of diethyl ether, and 200 mL of distilled water were added. The aqueous layer was separated using a separatory funnel and discarded, while the ether layer was washed twice with 400 mL of distilled water. Anhydrous magnesium was added to the ether layer, which was then dried and filtered. The filtrate (ether layer) was concentrated under reduced pressure using an evaporator (90°C / 3 mmHg), yielding a crude product in the form of a yellow-brown powder as a solid. This crude product was recrystallized from n-hexane and dried in vacuo to yield 46 g (0.12 mol) of a white powder of carboxylated hydrogenated cardanol. The carboxylated hydrogenated cardanol was dehydrated with acetic anhydride to obtain an acid anhydride-modified hydrogenated cardanol. Specifically, the acid anhydride-modified hydrogenated cardanol was prepared as follows. 17.2 g of carboxylated hydrogenated cardanol was dissolved in 114 mL of acetic anhydride with heating and stirred at 123°C for 1 hour. The temperature was then increased while distilling off the acetic anhydride under reduced pressure, and the mixture was stirred while heating at 140°C and 7 Torr (933 Pa) for 2 hours. The component that remained undistilled was the product, acid anhydride-modified hydrogenated cardanol. The carbon number of the resulting long-chain reactant (acid anhydride-modified hydrogenated cardanol) was 46.

[0140] (Comparative Example A1) A cellulosic material was produced in the same manner as in Example A1, except that the washing step was omitted. That is, the cellulosic material of this comparative example was the crude solid matter obtained in the esterification step.

[0141] (Comparative example A2) A cellulosic material was produced in the same manner as in Example A1, except that the liquid used in the washing step was changed to pure water at 20°C.

[0142] The conditions for the cleaning step for Examples A1 to A7 and Comparative Examples A1 and A2 are summarized in FIG.

[0143] [8] Preparation of molding material Example B1 Cellulose fiber (manufactured by CMPC, Guaiba BEKP): 70 parts by mass, and the cellulose-based material produced in Example A1: 30 parts by mass were weighed. Then, these were charged into a twin-screw kneader (manufactured by Technobel, KZW15TW-45MG) and kneaded. The kneading conditions were a maximum heating temperature of 180°C and an extrusion discharge rate of 1 kg / hr. Next, the strands were processed into a strand-like material and then pelletized into a pelletized molding material using a pelletizer.

[0144] (Examples B2 to B11) A pellet-shaped molding material was prepared in the same manner as in Example B1, except that the types of components to be kneaded and the compounding ratio of each component were changed as shown in FIG.

[0145] (Comparative examples B1 and B2) A pellet-shaped molding material was prepared in the same manner as in Example B1, except that the types of components to be kneaded and the compounding ratio of each component were changed as shown in FIG.

[0146] [9] Manufacturing of molded bodies The molding materials of Examples B1 to B11 and Comparative Examples B1 and B2 were each injection molded using an injection molding machine (THX40-5V, manufactured by Nissei Plastic Industrial Co., Ltd.) to produce molded articles for yellowing evaluation, flexural modulus evaluation, and Charpy impact strength evaluation, which will be described later. The heating temperature of the molding materials during injection molding was 200°C. The molded articles for yellowing evaluation, flexural modulus evaluation, and light resistance evaluation were rectangular plate-shaped molded articles with long sides of 80 mm ± 2 mm, short sides of 10.0 mm ± 0.2 mm, and a thickness of 4.0 mm ± 0.2 mm. The molded article for Charpy impact strength evaluation was a rectangular plate-shaped molded article with long sides of 80 mm ± 2 mm, short sides of 4.0 mm ± 0.2 mm, and a thickness of 10.0 mm ± 0.2 mm.

[0147]

[10] Evaluation The molded articles according to the above-mentioned Examples and Comparative Examples were evaluated as follows.

[0148] [10-1] Yellowing For each of the molded articles for yellowing evaluation according to Examples B1 to B11 and Comparative Examples B1 and B2, which were produced as described in [9] above, the yellowness index (YI) was determined in accordance with JIS K7373 using a spectrophotometer SQ7700 (manufactured by Nippon Denshoku Industries Co., Ltd.) and evaluated according to the following criteria: The higher the value, the higher the yellowness.

[0149] A: The yellowness index is less than 0.5. B: Yellowness index is 0.5 or more and less than 1.0. C: Yellowness index is 1.0 or more and less than 5.0. D: Yellowness index is 5.0 or more and less than 10. E: Yellowness index is 10 or more.

[0150] [10-2] Flexural modulus The molded articles for evaluating the flexural modulus of each of Examples B1 to B11 and Comparative Examples B1 and B2, which were produced as described in [9] above, were measured for flexural modulus in accordance with ISO 178 (JIS K7171) using an Instron 68TM-30, and evaluated according to the following criteria: The distance between supporting points was 64 mm in the measurement of the flexural modulus.

[0151] A: The flexural modulus is 2.0 GPa or more. B: The flexural modulus is 1.5 GPa or more and less than 2.0 GPa. C: The flexural modulus is 1.0 GPa or more and less than 1.5 GPa. D: The flexural modulus is 0.5 GPa or more and less than 1.0 GPa. E: The flexural modulus is less than 0.5 GPa.

[0152] [10-3] Charpy impact strength The molded articles for Charpy impact strength evaluation according to Examples B1 to B11 and Comparative Examples B1 and B2, which were produced as described in [9] above, were subjected to measurement of Charpy impact strength in accordance with ISO 179 (JIS K7111) using an Impact Tester IT manufactured by Toyo Seiki Seisaku-sho, Ltd., and evaluated according to the following criteria: The hammer weight was 4J (WR 2.14 N / m), the lifting angle was 150°, the remaining notch width was 8.0 mm ± 0.2 mm, and the notch angle was 45°.

[0153] A: Charpy impact strength is 10kJ / m 2 That's all. B: Charpy impact strength is 8kJ / m 2 More than 10kJ / m 2 is less than. C: Charpy impact strength is 6kJ / m 2 More than 8kJ / m 2 is less than. D: Charpy impact strength is 6kJ / m 2 is less than.

[0154] [10-4] Lightfastness The molded articles for evaluating light resistance according to Examples B1 to B11 and Comparative Examples B1 and B2, which were manufactured as described in [9] above, were subjected to a light exposure test using a water-cooled xenon arc weather meter (model Ci35A) manufactured by Atlas Co., Ltd., and evaluated according to the following criteria. In the light exposure test, the molded articles were wrapped around a metal frame and set in the device, quartz was used for the inner filter glass and porosicate, type S, was used for the outer filter glass, and the irradiance was 0.35 W / m 2 (at 340 nm), black panel temperature: 83±3°C, humidity inside the test chamber: 25±5%, and continuous operation was carried out for 100 hours.

[0155] A: The change in yellowness before and after light exposure is less than 1%. B: The change in yellowness before and after light exposure is 1% or more and less than 5%. C: The change in yellowness before and after exposure to light is 5% or more and less than 10%. D: The change in yellowness before and after light exposure is 10% or more and less than 20%. E: The change in yellowness before and after light exposure is 20% or more.

[0156] These results, along with the compositions of the molding materials of Examples B1 to B11 and Comparative Examples B1 and B2, are summarized in Figure 2. Figure 2 also shows the DS values of the cellulose derivatives contained in the molding materials of Examples B1 to B11 and Comparative Examples B1 and B2, the contents of volatile organic compounds and nitrogen-containing organic impurities in the cellulosic materials, and the results of yellowing evaluation of the cellulosic materials of Examples B1 to B11 and Comparative Examples B1 and B2.

[0157] The DS values shown in Figure 2 were determined by neutralization titration as shown below. Specifically, 0.30 g of cellulose-based material was dispersed in 25 mL of dimethyl sulfoxide, heated and stirred at 90°C for 30 minutes, and then cooled to room temperature. 25 mL of 0.5 N potassium hydroxide-ethanol solution was added, and heated and stirred at 90°C for 60 minutes to hydrolyze the cellulose acetate and liberate acetic acid. The mixture was then cooled to room temperature, and 25 mL of 0.5 N hydrochloric acid was added and stirred for 30 minutes. The amount of liberated acid was then determined by neutralization titration with 0.1 N aqueous sodium hydroxide solution, and the DS value was calculated from the amount of liberated acid.

[0158] The volatile organic compound content in Figure 2 is shown as a value determined by the following measurement. Approximately 5 g of cellulosic material was weighed and the volatile organic compounds were removed in a vacuum dryer at a temperature of 80°C, a vacuum of 50 Pa, and a processing time of 5 hours. The mass of the cellulosic material was then weighed again to determine the mass loss rate, which was used as the volatile organic compound content. In Figure 2, the volatile organic compound content determined as above is indicated as "A" for less than 1% by mass, "B" for 1% to less than 5% by mass, "C" for 5% to less than 8% by mass, "D" for 8% to less than 10% by mass, and "E" for 10% or more by mass.

[0159] The content of nitrogen-containing organic impurities in Figure 2 was determined by the following measurement. Approximately 5 g of cellulose-based material was weighed, chloroform was added, and the mixture was left to stand for 10 minutes. The insoluble matter was then filtered off. The filtrate was then introduced into a gas chromatograph, and the amount of nitrogen-containing organic impurities (DMAP) was calculated. The amount of the impurity was calculated by preparing three DMAP solutions with different concentrations and creating a calibration curve.

[0160] The yellowing evaluation of the cellulose-based materials was carried out according to the same method and evaluation criteria as explained in [10-2] above.

[0161] In Fig. 2, cellulose fibers (Guaiba BEKP, manufactured by CMPC) are shown as "cellulose fibers." The numerical values for the content of each component in Fig. 2 are shown in units of mass %.

[0162] As is clear from Figure 2, excellent results were obtained in each of the Examples, whereas satisfactory results were not obtained in each of the Comparative Examples.

Claims

1. A cellulose-based material comprising a cellulose derivative in which a hydroxy group of cellulose is esterified, Yellowness index is less than 1.0, A cellulosic material having a volatile organic compound content of less than 5% by mass.

2. 2. The cellulosic material of claim 1, wherein the volatile organic compound content is less than 1% by weight.

3. 2. The cellulosic material according to claim 1, wherein the content of organic impurities containing nitrogen atoms is 1000 ppm or less.

4. 2. The cellulosic material according to claim 1, wherein the DS value for the cellulose derivative is 2.0 or more and 3.0 or less.

5. 2. The cellulose-based material according to claim 1, wherein the cellulose derivative has a structure in which at least a portion of the hydroxyl groups of cellulose are substituted with an ester group having 2 to 48 carbon atoms or a group derived from a cardanol derivative.

6. Cellulose fibers, A molding material comprising the cellulosic material according to any one of claims 1 to 5.

7. The content of the cellulose fiber is 40% by mass or more and 90% by mass or less, The molding material according to claim 6 , wherein the content of the cellulose derivative is 10% by mass or more and 60% by mass or less.

8. Cellulose fibers, A molded body made of a material containing the cellulose-based material according to any one of claims 1 to 5.

9. The content of the cellulose fiber is 40% by mass or more and 90% by mass or less, The molded article according to claim 8 , wherein the content of the cellulose derivative is 10% by mass or more and 60% by mass or less.

10. The molded article according to claim 8, having a yellowness index of less than 1.

0.

11. 1. A method for producing a cellulosic material containing a cellulose derivative in which a hydroxy group of cellulose is esterified, comprising: an esterification step of esterifying the cellulose; a washing step of washing the composition obtained in the esterification step with an acidic aqueous solution or water at 50°C or higher.

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