Molding material and method for producing molding material

Abstract

To provide: a molding material that contains cellulose fibers in a predetermined content range and is suitably usable for producing molded articles excellent in impact resistance, strength, and heat resistance; and a method for producing the molding material.SOLUTION: The molding material according to the present invention comprises: cellulose fibers; and a specific cellulose derivative in which part of the hydrogen atoms constituting hydroxyl groups of cellulose is substituted with a polymer structure including at least one of a unit structure of the formula (1) in the figure and a unit structure in which -NH- in the formula (1) is replaced with -O-; where the content of the cellulose fibers is 80 mass% or less. (In the formula (1), R1 represents an alkylene group having 2 to 15 carbon atoms.)SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a molding material and a method for producing the molding material.

Background Art

[0002] As a measure against oil depletion and global warming, attempts have been made to replace conventional plastic materials with molding materials using cellulose, which is a natural material rich in plant origin.

[0003] For example, a molded body containing natural cellulose fibers and a cellulose ester such as cellulose acetate butyrate or cellulose acetate propionate has been proposed as a non-woven web or composite structure that can be treated in a compost landfill (see Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, such a molded body has problems of inferior impact resistance, strength, and heat resistance.

Means for Solving the Problems

[0006] The present invention has been made to solve the above problems and can be realized as the following application examples.

[0007] The molding material according to the application example of the present invention includes cellulose fibers and a specific cellulose derivative in which a part of the hydrogen atoms constituting the hydroxyl groups of cellulose is substituted with a polymerization structure including at least one unit structure of the following formula (1) and the following formula (2). The content of the cellulose fibers is 80% by mass or less.

[0008]

Chem.

[0009]

Chem.

[0010] Further, the method for producing a molding material according to an application example of the present invention includes a polymerization step of polymerizing cellulose and a ring-opening polymerizable monomer to obtain a specific cellulose derivative, and a kneading step of kneading the specific cellulose derivative with cellulose fibers.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0012] Hereinafter, preferred embodiments of the present invention will be described in detail. [1] Molding Material First, the molding material of the present invention will be described.

[0013] The molding material of the present invention includes cellulose fibers and a specific cellulose derivative in which a part of the hydrogen atoms constituting the hydroxyl groups of cellulose is substituted with a polymerization structure containing at least one unit structure of the following formula (1) and the following formula (2), and the content of the cellulose fibers is 80% by mass or less.

[0014]

Chem.

[0015] [Chemical formula] (In formula (2), R2 is an alkylene group having 2 to 15 carbon atoms.)

[0016] With such a configuration, it is possible to provide a molding material that can be suitably used for manufacturing a molded article excellent in impact resistance, strength, and heat resistance. Further, the moldability during the manufacture of the molded article is also excellent.

[0017] It is considered that such excellent effects are obtained for the following reasons. That is, together with cellulose having high theoretical strength and excellent shape stability, a specific cellulose derivative having excellent compatibility and affinity with cellulose fibers, excellent heat resistance and toughness, and excellent fluidity during melting is included, thereby preventing and suppressing the cancellation of the functions of these components, and enabling the functions of these components to be fully exerted. More specifically, during the manufacture of a molded article using the molding material or in a molded article manufactured using the molding material, while fully exerting the functions of cellulose fibers and a specific cellulose derivative, the wettability of the specific cellulose derivative with respect to the cellulose fibers can be increased, and interfacial peeling between different components constituting the molded article can be suitably prevented and suppressed. As a result, it is considered that the excellent effects as described above can be obtained.

[0018] Further, since interfacial peeling between different components constituting the molded article can be suitably prevented and suppressed, it is possible to obtain a molded article in which problems such as dust generation are effectively prevented.

[0019] In addition, by containing cellulose fibers, which are natural materials rich in plant origin, it is possible to suitably address environmental problems and the conservation of buried resources, etc., and it is also advantageous from the viewpoints of stable supply of molding materials and molded articles manufactured using the same, cost reduction, etc. Further, cellulose fibers are components contained in large amounts not only in virgin pulp but also in waste paper, old cloth, etc., and are also advantageous from the viewpoint of promoting effective reuse of resources.

[0020] Moreover, specific cellulose derivatives can be suitably obtained using cellulose as described above as a raw material, and are generally components having excellent biodegradability. Thereby, also the entire molding material and the entire molded article manufactured using the molding material can suitably address environmental problems and the like.

[0021] On the other hand, when the above conditions are not satisfied, satisfactory results cannot be obtained. For example, even if it contains cellulose fibers, if it does not contain a specific cellulose derivative, the molded article manufactured using the molding material will have extremely poor impact resistance and strength. Also, the moldability during the manufacture of the molded article will be poor.

[0022] Further, if another cellulose derivative is used instead of the specific cellulose derivative and the specific cellulose derivative is not contained, the impact resistance, strength, and heat resistance of the molded article manufactured using the molding material will be poor.

[0023] Also, even if the molding material contains cellulose fibers and a specific cellulose derivative, if the content of cellulose fibers in the molding material exceeds 80% by mass, the content of the specific cellulose derivative will relatively decrease, and the impact resistance, strength, etc. of the molded article will rapidly decrease.

[0024] [1-1] Cellulose fibers The molding material of the present invention contains cellulose fibers.

[0025] Cellulose fibers are the main component of the molding material of the present invention, and greatly contribute to maintaining the shape of the molded body produced using the molding material of the present invention, and are components that greatly affect the properties such as the strength of the molded body.

[0026] Cellulose is a natural material rich in plant origin. Therefore, by using cellulose fibers, it is possible to suitably respond to environmental problems and conservation of buried resources, etc., and it is also preferable from the viewpoints of stable supply of the molding material and the molded body produced using it, cost reduction, etc. In addition, cellulose fibers have particularly high theoretical strength among various fibers, and are also advantageous from the viewpoint of improving the strength of the molded body.

[0027] As the cellulose fibers, virgin pulp may be used, or waste paper, waste cloth, etc. may be reused.

[0028] Cellulose fibers are usually mainly composed of cellulose, but may contain components other than cellulose. Examples of such components include hemicellulose, lignin, etc.

[0029] Also, as the cellulose fibers, those subjected to treatments such as bleaching may be used. Examples of the cellulose fibers include cotton, hemp, rayon, cupra, etc.

[0030] The content of the cellulose fibers in the molding material may be 80% by mass or less, preferably 40% by mass or more and 80% by mass or less, more preferably 45% by mass or more and 78% by mass or less, and still more preferably 50% by mass or more and 75% by mass or less.

[0031] As a result, it will contain more cellulose fibers, which are natural materials rich in plant origin, so it can preferably cope with environmental problems and conservation of buried resources, etc., and is more preferable from the viewpoints of stable supply of molding materials and molded articles manufactured using the same, cost reduction, etc., and is also more preferable from the viewpoint of improving the strength of the molded article. Further, the plasticity and moldability of the molding material will be more excellent.

[0032] When the content of cellulose fibers in the molding material is XF [mass%], the content of the specific cellulose derivative is XD1 [mass%], and the content of the second cellulose derivative is XD2 [mass%], the value of [XF / (XF + XD1 + XD2)]×100, that is, the ratio of the content of cellulose fibers to the total content of cellulose fibers, the specific cellulose derivative and the second cellulose derivative in the molding material is preferably 50 mass% or more and 80 mass% or less, more preferably 55 mass% or more and 78 mass% or less, and still more preferably 60 mass% or more and 75 mass% or less.

[0033] As a result, it will contain more cellulose fibers, which are natural materials rich in plant origin, so it can preferably cope with environmental problems and conservation of buried resources, etc., and is more preferable from the viewpoints of stable supply of molding materials and molded articles manufactured using the same, cost reduction, etc., and is also more preferable from the viewpoints of improving the impact resistance, strength, and heat resistance of the molded article. Further, the plasticity and moldability of the molding material will be more excellent.

[0034] 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 still more preferably 1 μm or more and 50 μm or less.

[0035] As a result, the affinity and compatibility with specific cellulose derivatives of cellulose fibers and the second cellulose derivatives described later become more excellent, and the shape stability, impact resistance, strength, heat resistance, etc. of the molded body manufactured using the molding material can be made more excellent. Further, the generation of dust in the molded body manufactured using the molding material can be more effectively prevented and suppressed. Further, the occurrence of unintended unevenness on the surface of the molded body manufactured using the molding material can be more effectively prevented. The fiber length of the cellulose fiber is determined by a method conforming to ISO 16065-2:2007.

[0036] The average thickness of the cellulose fiber 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 20 μm or less.

[0037] As a result, the shape stability, strength, etc. of the molded body manufactured using the molding material can be made more excellent. Further, the occurrence of unintended unevenness on the surface of the molded body manufactured using the molding material can be more effectively prevented.

[0038] The average aspect ratio of the cellulose fiber, that is, the average length with respect to the average thickness, is not particularly limited, but is preferably 10 or more and 1000 or less, and more preferably 15 or more and 100 or less.

[0039] As a result, the shape stability, strength, etc. of the molded body manufactured using the molding material can be made more excellent. Further, the generation of dust in the molded body manufactured using the molding material can be more effectively prevented and suppressed. Further, the occurrence of unintended unevenness on the surface of the molded body manufactured using the molding material can be more effectively prevented.

[0040] [1-2] Specific cellulose derivative The molding material of the present invention contains a specific cellulose derivative.

[0041] The specific cellulose derivative is a compound in which some of the hydrogen atoms constituting the hydroxyl groups of cellulose are substituted with a polymerized structure containing at least one unit structure of the above formula (1) and the above formula (2).

[0042] When the specific cellulose derivative contains at least the chemical structure of the above formula (1), R1 in the above formula (1) may be an alkylene group having 2 or more and 15 or less carbon atoms, preferably a linear alkylene group having 3 or more and 7 or less carbon atoms, and more preferably a linear alkylene group having 4 or 5 carbon atoms.

[0043] Thereby, the impact resistance, strength, and heat resistance of the molded body produced using the molding material can be made more excellent. Also, the moldability during the production of the molded body can be made more excellent.

[0044] When the specific cellulose derivative has the chemical structure represented by the above formula (1), the specific cellulose derivative may have two or more chemical structures under different conditions as the chemical structure represented by the above formula (1).

[0045] When the specific cellulose derivative contains at least the chemical structure of the above formula (2), R2 in the above formula (2) may be an alkylene group having 2 or more and 15 or less carbon atoms, preferably a linear alkylene group having 3 or more and 7 or less carbon atoms, and more preferably a linear alkylene group having 4 or 5 carbon atoms.

[0046] Thereby, the heat resistance of the molded body produced using the molding material can be made more excellent.

[0047] When the specific cellulose derivative has the chemical structure represented by the above formula (2), the specific cellulose derivative may have two or more chemical structures under different conditions as the chemical structure represented by the above formula (2).

[0048] The polymerization structure may contain at least one of the structures of the above formula (1) and the above formula (2) as the unit structure, but preferably contains both the structure of the above formula (1) and the structure of the above formula (2).

[0049] Thereby, the heat resistance of the molded body manufactured using the molding material can be made further excellent.

[0050] The number of unit structures per one polymerization structure in the specific cellulose derivative, that is, the average degree of polymerization in the polymerization structure is not particularly limited, but is preferably 2 or more and 50 or less, more preferably 3 or more and 40 or less, and still more preferably 5 or more and 30 or less.

[0051] Thereby, it becomes a heat flow temperature suitable for molding processing, and the moldability at the time of manufacturing the molded body can be made more excellent.

[0052] The DS value of the polymerization structure in the specific cellulose derivative, that is, the substitution degree corresponding to the number of hydrogen atoms of all hydroxyl groups of cellulose substituted by the polymerization structure divided by the number of glucose constituting the cellulose is preferably 0.1 or more and 0.8 or less, more preferably 0.2 or more and 0.7 or less, and still more preferably 0.2 or more and 0.6 or less.

[0053] Thereby, the impact resistance, strength, and heat resistance of the molded body manufactured using the molding material can be made more excellent. Also, the moldability at the time of manufacturing the molded body can be made more excellent.

[0054] The molding material of the present invention may contain at least one specific cellulose derivative, but preferably contains two or more specific cellulose derivatives.

[0055] Thereby, the impact resistance, strength, and heat resistance of the molded body manufactured using the molding material can be made further excellent. Also, the moldability at the time of manufacturing the molded body can be made further excellent.

[0056] The weight-average molecular weight of the specific cellulose derivative is preferably 200,000 or more and 2,000,000 or less, more preferably 300,000 or more and 1,000,000 or less.

[0057] Thereby, the affinity and compatibility of the specific cellulose derivative with respect to the cellulose fiber can be made more excellent, and the impact resistance, strength, and heat resistance of the molded body manufactured using the molding material can be made more excellent. Further, the moldability during the production of the molded body can be made more excellent.

[0058] The glass transition temperature of the specific cellulose derivative is preferably 80°C or more and 200°C or less, more preferably 90°C or more and 180°C or less, still more preferably 100°C or more and 170°C or less.

[0059] Thereby, the affinity and compatibility of the specific cellulose derivative with respect to the cellulose fiber can be made more excellent, and the impact resistance, strength, and heat resistance of the molded body manufactured using the molding material can be made more excellent. Further, the moldability during the production of the molded body can be made more excellent.

[0060] The content of the specific cellulose derivative in the molding material is preferably 10% by mass or more and 40% by mass or less, more preferably 13% by mass or more and 30% by mass or less, still more preferably 15% by mass or more and 25% by mass or less.

[0061] Thereby, the impact resistance, strength, and heat resistance of the molded body manufactured using the molding material can be made more excellent. Further, the moldability during the production of the molded body can be made more excellent.

[0062] When the content of cellulose fibers in the molding material is XF [mass%], the content of a specific cellulose derivative is XD1 [mass%], and the content of a second cellulose derivative is XD2 [mass%], the value of [XD1 / (XF + XD1 + XD2)]×100, that is, the ratio of the content of the specific cellulose derivative to the total content of cellulose fibers, the specific cellulose derivative, and the second cellulose derivative in the molding material is preferably 10 mass% or more and 50 mass% or less, more preferably 12 mass% or more and 45 mass% or less, and even more preferably 15 mass% or more and 40 mass% or less.

[0063] Thereby, while more effectively preventing an increase in the cost of the molding material, the impact resistance, strength, and heat resistance of the molded body produced using the molding material can be made more excellent. Also, the moldability during the production of the molded body can be made more excellent.

[0064] When the content of cellulose fibers in the molding material is XC [mass%] and the content of a specific cellulose derivative is XD1 [mass%], it preferably satisfies the relationship of 0.14≦XD1 / XC≦0.80, more preferably satisfies the relationship of 0.19≦XD1 / XC≦0.60, and even more preferably satisfies the relationship of 0.22≦XD1 / XC≦0.50.

[0065] Thereby, the impact resistance, strength, and heat resistance of the molded body produced using the molding material can be made more excellent. Also, the moldability during the production of the molded body can be made more excellent.

[0066] [1-3] Second Cellulose Derivative The molding material of the present invention preferably contains, in addition to the above-described cellulose fibers and specific cellulose derivative, a second cellulose derivative that does not contain either the structure of the above formula (1) or the structure of the above formula (2).

[0067] Such a second cellulose derivative is excellent in affinity and compatibility with the specific cellulose derivative described above. By including such a second cellulose derivative, the strength, impact resistance, etc. of a molded article produced using a molding material can be made more excellent. Further, the moldability during the production of the molded article can be made more excellent.

[0068] The second cellulose derivative preferably has at least one alkyl group having 1 to 18 carbon atoms as a modifying group and has a DS value in the range of 1.0 or more and 2.5 or less.

[0069] Thereby, the flexural modulus of elasticity of a molded article produced using a molding material becomes particularly excellent.

[0070] As described above, the second cellulose derivative preferably has at least one alkyl group having 1 to 18 carbon atoms as a modifying group. More preferably, the number of carbon atoms of the alkyl group is 1 to 12, and even more preferably 1 to 8. Thereby, the above-described effects are more significantly exhibited.

[0071] Also, as described above, the DS value of the second cellulose derivative is preferably 1.6 or more and 3.0 or less, more preferably 1.7 or more and 2.8 or less, and even more preferably 1.9 or more and 2.6 or less. Thereby, the above-described effects are more significantly exhibited.

[0072] The second cellulose derivative is preferably at least one selected from the group consisting of cellulose acetate propionate, cellulose acetate butyrate, and cellulose diacetate.

[0073] Thereby, it is more preferable from the viewpoints of stable supply of the molding material and the molded article produced using the same, cost reduction, etc., and also more preferable from the viewpoints of improvement in impact resistance, strength, and heat resistance of the molded article. Further, the plasticity and moldability of the molding material become more excellent.

[0074] When the forming material contains a second cellulose derivative, when the content of cellulose fibers in the forming material is XF [% by mass], the content of the specific cellulose derivative is XD1 [% by mass], and the content of the second cellulose derivative is XD2 [% by mass], the value of [XD2 / (XF + XD1 + XD2)]×100, that is, the ratio of the content of the second cellulose derivative to the total content of cellulose fibers, the specific cellulose derivative and the second cellulose derivative in the forming material is preferably 40% by mass or less, more preferably 10% by mass or more and 36% by mass or less, and even more preferably 12% by mass or more and 32% by mass or less.

[0075] This is more preferable from the viewpoints of stable supply of the forming material and the formed body manufactured using the same, cost reduction, etc., and is also more preferable from the viewpoints of improving the impact resistance, strength, and heat resistance of the formed body. Also, the plasticity and formability of the forming material become more excellent.

[0076] The content of the second cellulose derivative in the forming material is preferably 8% by mass or more and 40% by mass or less, more preferably 10% by mass or more and 36% by mass or less, and even more preferably 12% by mass or more and 32% by mass or less.

[0077] This is more preferable from the viewpoints of stable supply of the forming material and the formed body manufactured using the same, cost reduction, etc., and is also more preferable from the viewpoints of improving the impact resistance, strength, and heat resistance of the formed body. Also, the plasticity and formability of the forming material become more excellent.

[0078] [1-4] Flame retardant The forming material of the present invention may further contain a flame retardant. Thereby, the flame retardancy of the formed body manufactured using the forming material can be improved.

[0079] Examples of the flame retardant include brominated flame retardants, chlorinated flame retardants, phosphorus-containing flame retardants, silicon-containing flame retardants, nitrogen compound-based flame retardants, inorganic flame retardants, and the like.

[0080] Among these, when mixed and kneaded with other components or during molding processing, they do not thermally decompose to generate hydrogen halide, which corrodes processing machines and molds or deteriorates the working environment. Also, when incinerated and discarded, there is little possibility of halogen volatilization or decomposition to generate dioxins and the like, which have an adverse impact on the environment. Therefore, phosphorus-containing flame retardants and silicon-containing flame retardants are preferred.

[0081] Examples of the phosphorus-containing flame retardant include organic phosphorus-based compounds such as phosphate esters, condensed phosphate esters, and polyphosphates.

[0082] Examples of the phosphate ester 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, cresyldiphenyl phosphate, xylenyl diphenyl phosphate, diphenyl(2-ethylhexyl) phosphate, di(isopropylphenyl)phenyl phosphate, monoisodecyl phosphate, 2-acryloyloxyethyl acid phosphate, 2-methacryloyloxyethyl acid phosphate, diphenyl-2-acryloyloxyethyl phosphate, diphenyl-2-methacryloyloxyethyl phosphate, melamine phosphate, dimelamine phosphate, melamine pyrophosphate, triphenylphosphine oxide, tricresylphosphine oxide, diphenyl methane phosphonate, diethyl phenylphosphonate, and the like.

[0083] Examples of the condensed phosphate ester include aromatic condensed phosphate 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.

[0084] In addition, polyphosphate salts composed of salts of phosphoric acid, polyphosphoric acid with metals of Groups 1 to 14 of the periodic table, ammonia, aliphatic amines, and aromatic amines can also be mentioned. Representative salts of polyphosphate salts include lithium salts, sodium salts, calcium salts, barium salts, iron(II) salts, iron(III) salts, aluminum salts, etc. as metal salts, methylamine salts, ethylamine salts, diethylamine salts, triethylamine salts, ethylenediamine salts, piperazine salts, etc. as aliphatic amine salts, and pyridine salts, triazine salts, etc. as aromatic amine salts.

[0085] In addition to the above, halogen-containing phosphate esters such as tris(2-chloroethyl) phosphate, tris(dichloropropyl) phosphate, tris(β-chloropropyl) phosphate, phosphazene compounds having a structure in which a phosphorus atom and a nitrogen atom are bonded by a double bond, phosphate ester amides, etc. can be mentioned.

[0086] Examples of the silicon-containing flame retardant include organic silicon compounds having a two-dimensional or three-dimensional structure, polydimethylsiloxane, or those in which the methyl groups on the side chains or terminals of polydimethylsiloxane are substituted or modified with hydrogen atoms, substituted or unsubstituted aliphatic hydrocarbon groups, aromatic hydrocarbon groups, so-called silicone oils, or modified silicone oils.

[0087] Examples of the substituted or unsubstituted aliphatic hydrocarbon group and aromatic hydrocarbon group include alkyl group, cycloalkyl group, phenyl group, benzyl group, amino group, epoxy group, polyether group, carboxyl group, mercapto group, chloroalkyl group, alkyl higher alcohol ester group, alcohol group, aralkyl group, vinyl group, trifluoromethyl group, etc.

[0088] In addition, as flame retardants other than the phosphorus-containing flame retardant and the silicon-containing flame retardant, for example, magnesium hydroxide, aluminum hydroxide, antimony trioxide, antimony pentoxide, sodium antimonate, zinc hydroxystannate, zinc stannate, metatannic acid, tin oxide, tin oxide salt, 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 metalloids, ammonium sulfamate, ammonium bromide, zirconium-based compounds, guanidine-based compounds, fluorine-based compounds, graphite, expandable graphite and other inorganic flame retardants can be used.

[0089] 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 specific cellulose derivative is 100 parts by mass.

[0090] Thereby, while more effectively exerting the effects of the present invention described above, the flame retardancy of the molded article produced using the molding material of the present invention can be made more excellent.

[0091] The ratio of the content of the flame retardant to the total content of the cellulose fiber, the specific cellulose derivative and the second cellulose derivative in the molding material is preferably 1% by mass or more and 20% by mass or less, more preferably 2% by mass or more and 18% by mass or less, and even more preferably 3% by mass or more and 16% by mass or less.

[0092] Thereby, the flame retardancy of the molded article produced using the molding material can be made more excellent, the toughness of the molded article produced using the molding material can be made more excellent, and the Charpy impact strength can be made more excellent.

[0093] [1-5] Antioxidant The molding material of the present invention may further contain an antioxidant. This improves the stability of the resin against heating during the kneading and molding processes.

[0094] Examples of the antioxidant include phosphorus-based antioxidants, hindered phenol-based antioxidants (e.g., "Irganox 1010", "Irganox 1076", "Irganox 3114" manufactured by Ciba Specialty Chemicals, "Sumilizer GP" manufactured by Sumitomo Chemical Co., Ltd.), and the like.

[0095] 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 based on 100 parts by mass of the total content of the cellulose fiber and the specific cellulose derivative.

[0096] This can more preferably suppress a decrease in impact resistance, moldability, rigidity, bending strength, heat resistance, etc. that the specific cellulose derivative has, and can more preferably improve scratch resistance and antifouling properties.

[0097] [1-6] Other components The molding material of the present invention may contain components other than those described above. Hereinafter, in this item, such components are also referred to as "other components".

[0098] Examples of the other components include colorants, insect repellents, fungicides, antibacterial agents, antistatic agents, flame retardant aids, ultraviolet absorbers, aggregation inhibitors, mold release agents, processing aids, drip preventives, cellulose derivatives other than those described above, resin materials, plasticizers, and the like.

[0099] However, the content of the 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.

[0100] [2] Method for producing molding material Next, the method for producing the molding material of the present invention will be described.

[0101] The manufacturing method of the molding material of the present invention includes a polymerization step of polymerizing cellulose and a ring-opening polymerizable monomer to obtain a specific cellulose derivative, and a kneading step of kneading the specific cellulose derivative with cellulose fibers.

[0102] Thereby, it is possible to provide a manufacturing method of a molding material that can be suitably used for manufacturing a molded body excellent in impact resistance, strength, and heat resistance. Also, the moldability during the production of the molded body will be excellent.

[0103] As the ring-opening polymerizable monomer, a cyclic ester compound or a cyclic amide compound having 2 to 15 carbon atoms corresponding to the unit structure of the above formula (1) or the unit structure of the above formula (2) can be used. Also, a diester such as lactide may be used.

[0104] As the ring-opening polymerizable monomer, only one kind of compound may be used, or two or more kinds of compounds may be used in combination.

[0105] The polymerization step may be carried out under any conditions as long as cellulose and a ring-opening polymerizable monomer can be polymerized to obtain a specific cellulose derivative. For example, the reaction may be carried out in the solid phase or in the liquid phase.

[0106] When carrying out the reaction of the polymerization step in the liquid phase, it may be carried out in a state where at least a part of the reaction raw materials is melted, or it may be carried out in a state where at least a part of the reaction raw materials is dissolved in a solvent.

[0107] Examples of the solvent include cyclohexanone, cycloheptanone, cyclooctanone, cyclononanone, cyclodecanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-octanone, 3-octanone, 4-octanone, 2-nonanone, 3-nonanone, 4-nonanone, 5-nonanone, etc., and one kind or a combination of two or more kinds selected from these can be used.

[0108] In the polymerization step, a catalyst may be used. Examples of the catalyst include alkali metals such as sodium and potassium, derivatives thereof such as alkoxides, alkylaluminums represented by triethylaluminum and derivatives thereof, alkoxytitanium compounds represented by tetrabutyl titanate, organometals such as tin octylate and dibutyltin laurate, and metal halides such as tin chloride. One or more selected from these can be used in combination.

[0109] The reaction temperature in the polymerization step is not particularly limited, but is preferably 140°C or higher and 210°C or lower, more preferably 160°C or higher and 200°C or lower. Thereby, effects such as shortening of the reaction time and suppression of decomposition of the product can be obtained.

[0110] In the kneading step, at least a specific cellulose derivative and cellulose fibers may be kneaded, and further, components other than these may be kneaded.

[0111] In the kneading step, the timing of mixing the components may be the same or different.

[0112] In the kneading step, for example, a single-screw kneader, a twin-screw kneader, a multi-screw kneader, a mixer, a roll Banbury mixer, etc. can be used.

[0113] The method for producing the molding material of the present invention only needs to have at least a polymerization step and a kneading step, and may further have other steps. Examples of the other steps include a pretreatment step before the polymerization step, an intermediate treatment step performed between the polymerization step and the kneading step, and a post-treatment step after the kneading step. Examples of the intermediate treatment step include a purification step of removing and purifying by-products and unreacted raw materials contained in the product obtained by the polymerization step.

[0114] The strand-shaped molding material obtained by kneading may be pelletized using a pelletizer such as a strand method or a watering hot cut method to obtain a pellet-shaped molding material.

[0115] Also, the following method may be applied as a method for manufacturing the molding material. That is, the kneaded product of the above-described components may be formed into a sheet shape, and then, for example, using a shredder device, it may be cut into a desired shape to obtain a pellet-shaped molding material. The method of forming the kneaded product into a sheet shape is not particularly limited. For example, first, the kneaded product is deposited in the air to form a sheet-shaped deposit, and the deposit is compressed by a calendar device to remove air and increase the density. Next, it is heated non-contact using a heating furnace, and then, methods such as heat pressing using a heat press device can be mentioned. The shape and size of the pellets obtained by cutting are not particularly limited. For example, it can be made into a substantially rectangular parallelepiped with a length of one piece being 2 mm or more and 5 mm or less.

[0116] The cellulose fiber used in the production of the molding material of the present invention may be one that has been subjected to fibrillation treatment in advance. In particular, those obtained by defibrating a cellulose fiber source containing cellulose fibers such as waste paper may also be used.

[0117] [3] Molded body Next, the molded body according to the present invention will be described.

[0118] The molded body according to the present invention includes cellulose fibers and a specific cellulose derivative in which a part of the hydrogen atoms constituting the hydroxyl group of cellulose is substituted with a polymerization structure containing at least one unit structure of the above formula (1) and the above formula (2). And the content of cellulose fibers in the molded body according to the present invention is 80% by mass or less.

[0119] The molded body according to the present invention can be manufactured using the above-described molding material. Thereby, a molded body excellent in impact resistance, strength, and heat resistance can be provided.

[0120] Also, since interfacial peeling between different components constituting the molded body can be preferably prevented and suppressed, problems such as dust generation can be effectively prevented.

[0121] In addition, by containing cellulose fibers, which are natural materials rich in plant origin, it is possible to suitably respond to environmental problems and the conservation of buried resources, etc., and it is also advantageous from the viewpoints of stable supply of the molded body, cost reduction, etc. Further, cellulose fibers are components contained in large amounts not only in virgin pulp but also in waste paper, waste cloth, etc., and are also advantageous from the viewpoint of promoting effective reuse of resources.

[0122] In addition, specific cellulose derivatives can be suitably obtained using cellulose as described above as a raw material, and are generally components having excellent biodegradability. Thereby, the molded body as a whole can also suitably respond to environmental problems and the like.

[0123] Each component constituting the molded body preferably satisfies the conditions described in the above [1-1] to [1-6].

[0124] The shape of the molded body is not particularly limited, and may be any shape such as a sheet shape, a block shape, a spherical shape, a three-dimensional shape, etc.

[0125] The molded body may be for any use, and examples include various housings such as a housing of a printer, an ink cartridge, various containers, etc.

[0126] In particular, the molded body according to the present invention has a high affinity between cellulose fibers and a specific cellulose derivative, and effectively prevents dust generation, and thus can be suitably applied to an ink cartridge or the like where dust generation is particularly problematic.

[0127] The molded body according to the present invention may be manufactured by any method, but can be suitably manufactured, for example, by injection molding, press molding, etc. using the molding material of the present invention as described above.

[0128] As described above, the preferred embodiments of the present invention have been described, but the present invention is not limited thereto.

[0129] For example, the molding material of the present invention includes cellulose fibers and a specific cellulose derivative in which some of the hydrogen atoms constituting the hydroxyl groups of cellulose are substituted with a polymerized structure containing at least one of the unit structures of the above formula (1) and the above formula (2). The content of cellulose fibers may be 80% by mass or less, and it is not limited to those produced by the method described above.

Examples

[0130] Next, specific examples of the present invention will be described. [4] Synthesis of Specific Cellulose Derivative

[0131] (Synthesis Example 1) To a reactor equipped with a stirrer, an anchor-type stirring blade, a thermometer, and a reflux condenser, 100 parts by mass of cellulose fibers (manufactured by CMPC, Guaiba BEKP), 100 parts by mass of ε-caprolactone, and 50 parts by mass of cyclohexanone were added. After heating and stirring to 180 °C, 0.24 parts by mass of tin(II) octylate was added dropwise as a catalyst, and after reacting for 2 hours, the reaction product was taken out of the reactor, and 100 parts by mass of acetone was added. Then, this solution was dropped into 300 parts by mass of methanol to reprecipitate the resin. The precipitate was filtered off and dried under reduced pressure to obtain a specific cellulose derivative.

[0132] (Synthesis Examples 2 to 8) A specific cellulose derivative was synthesized in the same manner as in Synthesis Example 1 except that the type and amount of the ring-opening polymerizable monomer were as shown in FIG. 1.

[0133] The types and amounts of raw materials used in each synthesis example are collectively shown in FIG. 1. Note that for each specific cellulose derivative synthesized in each synthesis example, the number of unit structures per one of the polymerized structures in the specific cellulose derivative, that is, the average degree of polymerization in the polymerized structure is a value within the range of 2 or more and 50 or less, the DS value of the polymerized structure is a value within the range of 0.1 or more and 0.8 or less, the weight average molecular weight is a value within the range of 200,000 or more and 2,000,000 or less, and the glass transition temperature is a value within the range of 80 °C or more and 200 °C or less.

[0134] [5] Preparation of Molding Material (Example 1) Cellulose fiber (manufactured by CMPC, Guaiba BEKP): 80 parts by mass, specific cellulose derivative synthesized in Synthesis Example 1: 10 parts by mass, cellulose acetate butyrate (manufactured by Eastman Chemical Company, CAB-381-20): 10 parts by mass were weighed. Then, these were put into a twin-screw kneader (manufactured by Technovel, KZW15TW-45MG) and kneaded. The kneading conditions were a maximum heating temperature of 180°C and an extrusion discharge rate of 1 kg / hour. Next, after processing into a strand shape, it was made into a pellet-shaped molding material using a pelletizer.

[0135] (Examples 2 to 16) A pellet-shaped molding material was prepared in the same manner as in Example 1 except that the types of components to be kneaded and the blending ratios of each component were changed as shown in Figure 2.

[0136] (Comparative Examples 1 to 4) A pellet-shaped molding material was prepared in the same manner as in Example 1 except that the types of components to be kneaded and the blending ratios of each component were changed as shown in Figure 2.

[0137] [6] Manufacture of Molded Body For each of the molding materials of the above Examples and Comparative Examples 1 and 2, injection molding was performed using an injection molding machine (manufactured by Nissei Plastic Industrial Co., Ltd., THX40-5V) to manufacture a molded body for evaluating Charpy impact strength, a molded body for evaluating deflection temperature under load, and a molded body for evaluating flexural modulus, which will be described later. The heating temperature of the molding material during injection molding was 200°C. The molded body for evaluating Charpy impact strength was a rectangular plate-shaped molded body with a long side of 80.0 mm ± 2.0 mm, a short side of 4.0 mm ± 0.2 mm, and a thickness of 10.0 mm ± 0.2 mm. The molded bodies for evaluating deflection temperature under load and flexural modulus were rectangular plate-shaped molded bodies with a long side of 80.0 mm ± 2.0 mm, a short side of 10.0 mm ± 0.2 mm, and a thickness of 4.0 mm ± 0.2 mm.

[0138] Also, for the molding materials of Comparative Examples 3 and 4, press molding was performed using a press working device (manufactured by Towa Seiki Co., Ltd., hydraulic press PHKS-40ABS) to produce molded bodies for evaluating Charpy impact strength, molded bodies for evaluating heat distortion temperature under load, and molded bodies for evaluating flexural modulus, which will be described later. The heating temperature of the molding material during injection molding was set at 200°C. The molded body for evaluating Charpy impact strength was a rectangular plate-shaped molded body with a long side of 80.0 mm ± 2.0 mm, a short side of 4.0 mm ± 0.2 mm, and a thickness of 10.0 mm ± 0.2 mm. The molded bodies for evaluating heat distortion temperature under load and flexural modulus were rectangular plate-shaped molded bodies with a long side of 80.0 mm ± 2.0 mm, a short side of 10.0 mm ± 0.2 mm, and a thickness of 4.0 mm ± 0.2 mm.

[0139] [7] Evaluation The following evaluations were performed on the molded bodies according to each of the above Examples and Comparative Examples.

[0140] [7-1] Charpy Impact Strength Regarding the molded bodies for evaluating Charpy impact strength according to each of the above Examples and Comparative Examples, which were manufactured as described in [6] above, the Charpy impact strength was measured using an Impact Tester IT manufactured by Toyo Seiki Seisaku-sho, Ltd. in accordance with ISO 179 (JIS K7111), and evaluated according to the following criteria. In the measurement of Charpy impact strength, the hammer weight was 4 J (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°.

[0141] A: The Charpy impact strength is 10 kJ / m 2 or more. B: The Charpy impact strength is 8 kJ / m 2 or more and less than 10 kJ / m 2 C: The Charpy impact strength is 4 kJ / m 2 or more and less than 8 kJ / m 2 D: The Charpy impact strength is less than 4 kJ / m 2

[0142] ​​​[7-2] Heat Deflection Temperature For the molded articles for evaluating the heat deflection temperature according to the respective examples and comparative examples, which were produced as described in [6] above, the evaluation of the heat deflection temperature was performed by the flatwise method using an HDT tester 3M-2 manufactured by Toyo Seiki Seisakusho Co., Ltd. More specifically, the molded article for evaluating the heat deflection temperature was placed in a constant temperature bath at 30°C so that the distance between the fulcrums was 64 mm, and while applying a load of 1.8 MPa to a portion equidistant from the two fulcrums, the temperature in the constant temperature bath was raised at a rate of 120°C / hour. The process was terminated when the displacement of the molded article for evaluating the heat deflection temperature reached 0.34 mm, and the temperature at that time was taken as the load deflection temperature and evaluated according to the following criteria.

[0143] A: The heat deflection temperature is 80°C or higher. B: The heat deflection temperature is 70°C or higher and less than 80°C. C: The heat deflection temperature is 60°C or higher and less than 70°C. D: The heat deflection temperature is less than 60°C.

[0144] [7-3] Flexural Modulus For the molded articles for evaluating the flexural modulus according to the respective examples and comparative examples, which were produced as described in [6] above, the measurement of the flexural modulus was performed in accordance with ISO 178 (JIS K7171) using an Instron 68TM-30, and evaluated according to the following criteria. In the measurement of the flexural modulus, the distance between the fulcrums was 64 mm.

[0145] A: The flexural modulus is 2.0 GPa or higher. B: The flexural modulus is 1.5 GPa or higher and less than 2.0 GPa. C: The flexural modulus is 1.0 GPa or higher and less than 1.5 GPa. D: The flexural modulus is less than 1.0 GPa.

[0146] These results are summarized in FIG. 2 together with the composition of the molding material obtained in each of the above examples and comparative examples and the molding method of the molded article using the molding material.

[0147] In addition, in FIG. 2, cellulose fiber (manufactured by CMPC, Guaiba BEKP) is denoted as "cellulose fiber", cellulose acetate butyrate (manufactured by Eastman Chemical Company, CAB-381-20) is denoted as "CAB", cellulose acetate propionate (manufactured by Eastman Chemical Company, CAP-482-20) is denoted as "CAP", and diacetate cellulose (manufactured by Daicel Miraiz, DAC: L-70) is denoted as "DAC". The numerical values for each component in FIG. 2 indicate the content in units of mass%.

[0148] As is apparent from FIG. 2, excellent results were obtained in each of the above examples. On the other hand, satisfactory results were not obtained in each of the above comparative examples.

Claims

1. A molding material comprising cellulose fibers and a specific cellulose derivative in which some of the hydrogen atoms constituting the hydroxyl groups of cellulose are substituted with a polymerization structure containing at least one of the unit structures of the following formula (1) and the following formula (2), wherein the content of the cellulose fibers is 80% by mass or less. 【Chemical 1】 (In formula (1), R1 is an alkylene group having 2 or more and 15 or less carbon atoms.) 【Chemical Formula 2】 (In formula (2), R2 is an alkylene group having 2 or more and 15 or less carbon atoms.)

2. The molding material according to claim 1, further comprising a second cellulose derivative that does not contain any of the structures of formula (1) and formula (2).

3. The molding material according to claim 2, wherein the second cellulose derivative is at least one selected from the group consisting of cellulose acetate propionate, cellulose acetate butyrate, and cellulose diacetate.

4. When the content of the cellulose fibers in the molding material is XF [% by mass], the content of the specific cellulose derivative is XD1 [% by mass], and the content of the second cellulose derivative is XD2 [% by mass], the value of [XD2 / (XF + XD1 + XD2)] × 100 is 40% by mass or less. The molding material according to claim 2 or 3.

5. When the content of the cellulose fibers in the molding material is XF [% by mass], the content of the specific cellulose derivative is XD1 [% by mass], and the content of the second cellulose derivative is XD2 [% by mass], the value of [XD1 / (XF + XD1 + XD2)] × 100 is 10% by mass or more and 50% by mass or less. The molding material according to claim 2 or 3.

6. When the content of the cellulose fibers in the molding material is XF [% by mass], the content of the specific cellulose derivative is XD1 [% by mass], and the content of the second cellulose derivative is XD2 [% by mass], the value of [XF / (XF + XD1 + XD2)] × 100 is 50% by mass or more and 80% by mass or less. The molding material according to claim 2 or 3.

7. The specific cellulose derivative contains at least the chemical structure of formula (1), wherein R1 is a linear alkylene group having 3 or more and 7 or less carbon atoms. The molding material according to claim 1 or 2.

8. The molding material according to claim 7, wherein R1 is a linear alkylene group having 4 or 5 carbon atoms.

9. The specific cellulose derivative contains at least the chemical structure of the above formula (2). The molding material according to claim 1 or 2, wherein R2 is a linear alkylene group having 3 to 7 carbon atoms.

10. The molding material according to claim 9, wherein the polymerization structure contains both the structure of the above formula (1) and the structure of the above formula (2) as the unit structure.

11. The molding material according to claim 1 or 2, containing two or more of the specific cellulose derivatives.

12. The molding material according to claim 1 or 2, wherein the weight average molecular weight of the specific cellulose derivative is 300,000 or more and 1,000,000 or less.

13. The molding material according to claim 1 or 2, wherein the average length of the cellulose fiber is 500 μm or less.

14. A polymerization step of polymerizing cellulose and a ring-opening polymerizable monomer to obtain a specific cellulose derivative; A production method of a molding material, comprising a kneading step of kneading the specific cellulose derivative with cellulose fibers.

Images