Cellulose fatty acid ester and thermoplastic resin composition containing cellulose fatty acid ester

Abstract

Provided is a cellulose fatty acid ester that exhibits good mechanical properties and excellent molding processability.　A cellulose fatty acid ester according to the present disclosure is obtained by substituting hydroxyl groups of cellulose with a long chain fatty acid ester group and a short chain fatty acid ester group. The long chain fatty acid ester group is a saturated fatty acid ester group having 10-16 carbon atoms. The short chain fatty acid ester group is an acetoxy group. The substitution degree (DSL) of the long chain fatty acid ester group and the substitution degree (DSS) of the short chain fatty acid ester group satisfy formula (1) and formula (2).　(1): DSL+DSS≥2.7 (2): 0.3≤DSL / DSS≤5.0

Description

Cellulose fatty acid ester and thermoplastic resin composition containing cellulose fatty acid ester

[0001] The present disclosure relates to a cellulose fatty acid ester, a thermoplastic resin composition containing the cellulose fatty acid ester, a thermoplastic fiber containing the thermoplastic resin composition, a molded article containing the thermoplastic resin composition, and a method for producing the molded article. This application claims priority from Japanese Patent Application No. 2024-060417, filed in Japan on April 3, 2024, the contents of which are incorporated herein by reference.

[0002] Petroleum has traditionally been used as the raw material for plastic products used in a variety of fields, including PET bottles, medical equipment, automobile parts, and home appliances. However, because greenhouse gases emitted when petroleum-derived plastics are incinerated are thought to be one of the causes of global warming, there are currently studies being conducted on replacing petroleum-derived plastics with renewable biomass plastics made from plant-derived biomass.

[0003] Cellulose is one of the raw materials for biomass plastics, but because cellulose does not have thermoplastic properties, it is difficult to mold by heating or other means, making it unsuitable for molding processes.

[0004] As a method for solving the above problem, Patent Document 1 describes a cellulose fatty acid ester in which the hydroxyl groups of cellulose are substituted with short-chain aliphatic ester groups having 2 to 4 carbon atoms and linear or branched long-chain aliphatic ester groups having 5 to 20 carbon atoms.

[0005] In addition, cellulose fatty acid esters have been disclosed in which the hydroxyl groups of cellulose are substituted with short-chain aliphatic ester groups having about 2 to 4 carbon atoms and long-chain aliphatic ester groups having a larger carbon number than the short-chain aliphatic ester groups (Patent Documents 2 to 7).

[0006] JP 2010-121121 A, International Publication No. 2017 / 115634, JP 2021-193192 A, International Publication No. 2019 / 167641, International Publication No. 2019 / 049196, International Publication No. 2015 / 162787, International Publication No. 2022 / 085120

[0007] However, it has been found that when the long-chain aliphatic ester group of the cellulose fatty acid ester does not have a sufficient chain length, for example, when the number of carbon atoms is 9 or less, flexibility is poor and impact resistance is reduced. It has also been found that when the chain length of the long-chain aliphatic ester group is too long, for example, when the number of carbon atoms is 17 or more, brittleness occurs. Furthermore, it has been found that the melt viscosity increases and fluidity decreases, resulting in reduced moldability. Specifically, stress is applied during molding, making the resulting molded article prone to distortion. Furthermore, it has been found that when the ratio of the substitution degree of the long-chain aliphatic ester group to the substitution degree of the short-chain fatty acid ester group (substitution degree of long-chain aliphatic ester group / substitution degree of short-chain fatty acid ester group) is, for example, significantly less than 0.3 or significantly more than 5.0, the melt viscosity increases and fluidity decreases, resulting in reduced moldability. Specifically, stress is applied during molding, making the resulting molded article prone to distortion, and impact resistance is reduced.

[0008] Therefore, an object of the present disclosure is to provide a cellulose fatty acid ester that exhibits good mechanical properties and excellent moldability. Another object of the present disclosure is to provide a cellulose fatty acid ester that exhibits thermoplasticity, has a low melt viscosity, and can be used to form a molded article having excellent impact resistance. Another object of the present disclosure is to provide a thermoplastic resin composition made from biomass as a raw material, which can be used to form a molded article having a low melt viscosity and excellent impact resistance. Another object of the present disclosure is to provide a thermoplastic fiber made from biomass as a raw material, which can be used to form a molded article having a low melt viscosity and excellent impact resistance. Another object of the present disclosure is to provide a molded article made from biomass as a raw material and having excellent impact resistance. Another object of the present disclosure is to provide a method for producing a molded article having excellent impact resistance using biomass as a raw material.

[0009] As a result of intensive research to solve the above problems, the present inventors have found that, for a cellulose fatty acid ester having a long-chain aliphatic ester group and a short-chain aliphatic ester group, the number of carbon atoms in the long-chain aliphatic ester group is adjusted to a specific range, and the degree of substitution of the long-chain aliphatic ester group (DS) is adjusted to a specific range. Ｌ) and the degree of substitution of short-chain fatty acid ester groups (DS ｓ The present disclosure has been completed based on these findings.

[0010] That is, the present disclosure provides a cellulose fatty acid ester in which the hydroxyl groups of cellulose are substituted with long-chain fatty acid ester groups and short-chain fatty acid ester groups, wherein the long-chain fatty acid ester groups are saturated fatty acid ester groups having 10 to 16 carbon atoms, the short-chain fatty acid ester groups are acetoxy groups, and the degree of substitution (DS) of the long-chain fatty acid ester groups is Ｌ ) and the degree of substitution of short-chain fatty acid ester groups (DS Ｓ ) satisfies the following formulas (1) and (2): Ｌ +DS Ｓ ≧2.7 (1) 0.3≦DS Ｌ / DS Ｓ ≦5.0 (2)

[0011] The present disclosure also provides the cellulose fatty acid ester, which has a complex viscosity of 1500 Pa·s or less at a temperature of 180° C., a strain of 1.0%, and an angular frequency of 10 rad / s.

[0012] The present disclosure also provides the cellulose fatty acid ester, which, when subjected to DSC measurement according to the following temperature profile, exhibits a melting point peak in the temperature range of 100 to 160°C during the second heating process: Temperature profile: Heat from -80°C to 250°C at a rate of 20°C / min, cool from 250°C to -80°C at a cooling rate of 20°C / min, and then heat again from -80°C to 250°C at a heating rate of 20°C / min.

[0013] The present disclosure also provides a thermoplastic resin composition comprising the cellulose fatty acid ester.

[0014] The present disclosure also provides the thermoplastic resin composition, which is a resin composition for a 3D printer.

[0015] The present disclosure also provides the thermoplastic resin composition, which is an injection molding resin composition.

[0016] The present disclosure also provides a thermoplastic fiber comprising the cellulose fatty acid ester.

[0017] The present disclosure also provides a molded article of the thermoplastic resin composition.

[0018] The present disclosure also provides a method for producing a molded article, which comprises subjecting the thermoplastic resin composition to an injection molding process to obtain a molded article of the thermoplastic resin composition.

[0019] The cellulose fatty acid ester of the present disclosure is a renewable biomass plastic made from biomass. Therefore, replacing the cellulose fatty acid ester with petroleum-derived plastic raw materials can reduce greenhouse gas emissions. Furthermore, because the cellulose fatty acid ester has a specific degree of substitution of long-chain aliphatic ester groups having 10 to 16 carbon atoms, it has excellent thermoplasticity, low melt viscosity, and excellent fluidity. Furthermore, by appropriately substituting short-chain and long-chain fatty acid groups, the interaction between the long-chain fatty acid groups is moderately alleviated, allowing the formation of molded articles with excellent impact resistance. Note that if the carbon number of the long-chain aliphatic ester group exceeds the above range or if the degree of substitution of the long-chain aliphatic ester group exceeds the above range, the interaction between the long-chain aliphatic ester groups becomes excessive, resulting in brittleness and reduced fluidity. On the other hand, if the carbon number of the long-chain aliphatic ester group is below the above range or if the degree of substitution of the long-chain aliphatic ester group is below the above range and the degree of substitution of the short-chain fatty acid ester group exceeds the above range, the plastic will lack flexibility and have reduced impact resistance. Furthermore, thermoplasticity and fluidity are reduced. Because the thermoplastic resin composition of the present disclosure contains the cellulose fatty acid ester, it has a low melt viscosity, excellent moldability, and can form molded articles with excellent impact resistance. Furthermore, because the thermoplastic resin composition has a low melt viscosity, it is possible to form molded articles of any shape by molding the melt. For example, thermoplastic fibers obtained by molding the thermoplastic resin composition into fibers can be suitably used as raw materials for nonwoven fabrics, filters, and the like. Furthermore, because the thermoplastic resin composition has a low melt viscosity, it is possible to prevent excessive stress from being applied during molding processes such as injection molding. Therefore, it is possible to form molded articles without distortion and with good shape precision.

[0020] 1 is a diagram showing the results of DSC measurement of the cellulose fatty acid ester obtained in Example 1. FIG. 2 is a diagram showing the results of DSC measurement of the cellulose fatty acid ester obtained in Example 2. FIG. 3 is a diagram showing the results of DSC measurement of the cellulose fatty acid ester obtained in Comparative Example 1. FIG. 4 is a diagram showing the results of DSC measurement of the cellulose fatty acid ester obtained in Comparative Example 2.

[0021] [Cellulose fatty acid ester] The cellulose fatty acid ester of the present disclosure is a cellulose fatty acid ester in which the hydroxyl groups of cellulose are substituted with long-chain fatty acid ester groups and short-chain fatty acid ester groups. The long-chain fatty acid ester groups are saturated fatty acid ester groups having 10 to 16 carbon atoms, and the short-chain fatty acid ester groups are acetoxy groups. The degree of substitution (DS) of the long-chain fatty acid ester groups is Ｌ ) and the degree of substitution of short-chain fatty acid ester groups (DS ｓ ) satisfies the following formulas (1) and (2): Ｌ +DS Ｓ ≧2.7 (1) 0.3≦DS Ｌ / DS Ｓ ≦5.0 (2)

[0022] The cellulose fatty acid ester may form a salt.

[0023] Examples of the salts include monovalent metal salts such as alkali metal salts (lithium salts, sodium salts, potassium salts, rubidium salts, cesium salts, etc.), divalent metal salts such as alkaline earth metal salts (calcium salts, magnesium salts, etc.), quaternary ammonium salts, amine salts, substituted amine salts, and double salts thereof.

[0024] A cellulose fatty acid ester is a compound in which some or all of the hydroxyl groups (OH groups) of cellulose are substituted with aliphatic ester groups, and the aliphatic ester groups include at least one long-chain fatty acid ester group and a short-chain aliphatic ester group. Cellulose is a compound having a β-glucose ring unit represented by the following formula (1) as a repeating unit, and has hydroxyl groups at the 2-, 3-, and 6-positions of the β-glucose ring.

[0025] The cellulose fatty acid ester may be a polymer of β-glucose ring units having a long-chain fatty acid ester group and a short-chain aliphatic ester group, or a copolymer of β-glucose ring units having a long-chain fatty acid ester group and a β-glucose ring unit having a short-chain aliphatic ester group. The copolymer may be either a random copolymer or a block copolymer.

[0026] The short-chain fatty acid ester group is an acetoxy group (CH ３ COO group).

[0027] The long-chain fatty acid ester group is a group represented by the general formula RCOO, where R is a long-chain alkyl group having 9 to 15 carbon atoms. When the long-chain fatty acid ester group is a saturated fatty acid ester group having 10 to 16 carbon atoms, the melt viscosity is lower and the flowability is improved, compared with saturated fatty acid ester groups having 9 or less or 17 or more carbon atoms, and further, the impact resistance of the resulting molded article is improved (particularly, the onset of brittleness is suppressed in a low-temperature atmosphere of 0°C or less).

[0028] The alkyl group includes a straight chain alkyl group and a branched chain alkyl group.

[0029] Examples of the alkyl group include linear alkyl groups such as an n-nonyl group, an n-decyl group, an n-undecyl group, a lauryl group (or an n-dodecyl group), an n-tridecyl group, a myristyl group (an n-tetradecyl group), and an n-pentadecyl group; and branched alkyl groups such as a 1-methylnonyl group, a 1-ethyloctyl group, a 1-propylheptyl group, and a 1-butylhexyl group.

[0030] As the alkyl group, a linear alkyl group is preferred from the viewpoint of increasing the degree of substitution and suppressing the hydrophilicity and brittleness derived from the hydroxyl group.

[0031] The alkyl group may have a substituent. Examples of the substituent include a hydroxyl group and an alkoxy group (e.g., C １－１５Examples of the substituent that the alkoxy group may have include a mercapto group, a halogen atom, a cyano group, a sulfo group, a carboxy group, a nitro group, a hydroxamic acid group, a sulfino group, a hydrazino group, an imino group, etc. Examples of the substituent that the alkoxy group may have include the same examples as the substituent that the alkyl group may have.

[0032] As the alkyl group (having 9 to 15 carbon atoms), from the viewpoint of decreasing the melt viscosity and improving the flowability, and from the viewpoint of improving the impact resistance of the resulting molded body (particularly, suppressing the onset of brittleness in a low-temperature atmosphere of 0°C or less), the upper limit of the number of carbon atoms is preferably 14, particularly preferably 13, most preferably 12, and particularly preferably 11. Furthermore, from the viewpoint of increasing the hardness and improving the impact resistance, the lower limit of the number of carbon atoms is preferably 10.

[0033] Therefore, from the viewpoint of reducing the melt viscosity and improving the flowability, and from the viewpoint of improving the impact resistance of the resulting molded article (particularly, suppressing the onset of brittleness in a low-temperature atmosphere of 0° C. or less), the upper limit of the number of carbon atoms in the long-chain fatty acid ester group (having 10 to 16 carbon atoms) is preferably 15, particularly preferably 14, most preferably 13, and particularly preferably 12. Furthermore, from the viewpoint of increasing the hardness and improving the impact resistance, the lower limit of the number of carbon atoms is preferably 11.

[0034] The long-chain fatty acid ester group and the short-chain aliphatic ester group may be substituted on any of the 2-, 3-, and 6-hydroxyl groups of the β-glucose ring unit, and there are no particular limitations on the bonding position.

[0035] The degree of substitution of the long-chain fatty acid ester group in the cellulose fatty acid ester [DS Ｌ [DS: average value of the substitution degree of long-chain fatty acid ester groups for hydroxyl groups at the 2nd, 3rd, and 6th positions of the β-glucose ring unit (total substitution degree when two or more types of long-chain aliphatic ester groups are present)] is, from the viewpoint of improving the impact resistance of the obtained molded article (particularly, suppressing the occurrence of brittleness in a low-temperature atmosphere of 0° C. or less), for example, 0.7 or more, preferably 0.8 or more, more preferably 1.0 or more, even more preferably 1.2 or more, particularly preferably 1.4 or more, and most preferably 1.5 or more. Furthermore, from the viewpoint of reducing the melt viscosity and improving the fluidity, the substitution degree (DSＬ ) is, for example, 2.5 or less, preferably 2.3 or less, particularly preferably 2.0 or less, most preferably 1.8 or less, and particularly preferably 1.7 or less.

[0036] The degree of substitution of short-chain fatty acid ester groups in the cellulose fatty acid ester (DS Ｓ The degree of substitution (DS: average value of the degree of substitution of short-chain fatty acid ester groups for hydroxyl groups at the 2nd, 3rd, and 6th positions of the β-glucose ring unit) is, from the viewpoint of decreasing the melt viscosity and improving the flowability, for example, 0.5 or more, preferably 0.7 or more, more preferably 0.8 or more, even more preferably 1.0 or more, particularly preferably 1.2 or more, and most preferably 1.3 or more. Furthermore, from the viewpoint of improving the impact resistance of the obtained molded article (particularly, suppressing the occurrence of brittleness in a low-temperature atmosphere of 0° C. or less), the degree of substitution (DS Ｌ ) is, for example, 2.3 or less, preferably 2.0 or less, more preferably 1.8 or less, particularly preferably 1.6 or less, most preferably 1.5 or less, and particularly preferably 1.4 or less.

[0037] The degree of substitution of the long-chain fatty acid ester group in the cellulose fatty acid ester (DS Ｌ ) and the degree of substitution of short-chain fatty acid ester groups (DS ｓ ) Sum (DS Ｌ +DS Ｓ ) is 2.7 or more, and from the viewpoint of reducing the melt viscosity and improving the flowability, and from the viewpoint of improving the impact resistance of the resulting molded article, it is preferably 2.8 or more, particularly preferably 2.9 or more. Ｌ +DS Ｓ ) has an upper limit of 3.

[0038] Degree of substitution of long-chain fatty acid ester group (DS Ｌ ) and the degree of substitution of short-chain fatty acid ester groups (DS ｓ ) preferably satisfies the following formula (1-1), particularly preferably satisfies the following formula (1-2), and most preferably satisfies the following formula (1-3): 2.7≦DS Ｌ +DS Ｓ ≦3.0 (1-1) 2.8≦DS Ｌ +DS Ｓ≦3.0 (1-2) 2.9≦DS Ｌ +DS Ｓ ≦3.0 (1-3)

[0039] The degree of substitution of the long-chain fatty acid ester group in the cellulose fatty acid ester (DS Ｌ ) and the degree of substitution of short-chain fatty acid ester groups (DS Ｓ ) ratio (DS Ｌ / DS Ｓ When the ratio (DS) is 0.3 to 5.0, the melt viscosity is low, the flowability is improved, and the impact resistance of the resulting molded article is improved (particularly, the occurrence of brittleness in a low-temperature atmosphere of 0°C or less is suppressed). Ｌ / DS Ｓ The lower limit of the ratio (DS) is preferably 0.4, more preferably 0.5, even more preferably 0.6, still more preferably 0.8, particularly preferably 1.0, and most preferably 1.1, from the viewpoint of improving the impact resistance of the resulting molded article (particularly, suppressing the occurrence of brittleness in a low-temperature atmosphere of 0°C or less). Ｌ / DS Ｓ From the viewpoint of decreasing the melt viscosity and improving the flowability, the upper limit of the molten polymer (Nb) is more preferably 4.0, even more preferably 3.0, particularly preferably 2.5, and most preferably 1.5.

[0040] The degree of substitution of hydroxyl groups in cellulose fatty acid ester (DS Ｈ (i.e., the average value of unsubstituted hydroxyl groups among the hydroxyl groups at the 2-, 3-, and 6-positions of the β-glucose ring unit) is, for example, 0.3 or less, preferably 0.2 or less, and particularly preferably 0.1 or less.

[0041] The hydroxyl groups in the cellulose fatty acid ester may be substituted with a substituent other than the long-chain fatty acid ester group and the short-chain fatty acid ester group (hereinafter referred to as "other substituents"). However, the degree of substitution of the other substituents (DS) may be varied. Ｅ (average value of the degree of substitution of other substituents on the hydroxyl groups at the 2-, 3-, and 6-positions of the β-glucose ring unit) is, for example, 0.3 or less, preferably 0.2 or less, and particularly preferably 0.1 or less.

[0042] The degree of substitution of the long-chain fatty acid ester group in the cellulose fatty acid ester (DS Ｌ), the degree of substitution of short chain fatty acid ester groups (DS Ｓ ) can be calculated by measuring the amount of bound fatty acid per unit weight of β-glucose ring. Specifically, this can be carried out in accordance with ASTM-D817-91. Alternatively, in accordance with ASTM-817-96, a calibration curve can be prepared by measuring a plurality of cellulose mixed fatty acid esters with known degrees of substitution, and then the degrees of substitution at the 2-, 3-, and 6-positions of the β-glucose ring of the sample cellulose mixed fatty acid ester can be determined by NMR spectroscopy according to the method of Tezuka (Tezuka, Carbonydr. Res. 273, 83 (1995)).

[0043] That is, cellulose fatty acid ester (sample) was dissolved in deuterated chloroform, １３ The C-NMR spectrum is measured. The acetoxy group as a short-chain aliphatic ester group and the lauroyloxy group (C １１ H ２３ Taking a cellulose fatty acid ester having a β-glucose ring (DS) as an example, the carbon signals of the acetoxy group appear in the 2nd, 3rd, and 6th positions in the region of 168 to 171 ppm from the high magnetic field, and the signals of the carbonyl carbon of the lauroyloxy group appear in the 2nd, 3rd, and 6th positions in the region of 171 to 174 ppm. Then, by calculating the area ratio of each signal in the corresponding region based on the area of ​​the carbonyl signal of the acetoxy group and the area of ​​the carbonyl signal of the lauroyloxy group of a cellulose fatty acid ester with a known degree of substitution, the degree of substitution (DS) of the long-chain fatty acid ester group at the 2nd, 3rd, and 6th positions of the β-glucose ring of the cellulose fatty acid ester (sample) can be determined. Ｌ ) and the degree of substitution of short chain fatty acid ester groups (DS Ｓ ) can be obtained.

[0044] The weight average molecular weight (W １ ) is, for example, 50,000 to 800,000.

[0045] The weight average molecular weight (W １ ) is the polystyrene equivalent molecular weight determined by gel permeation chromatography (GPC).

[0046] The weight average degree of polymerization (DPw) of the cellulose fatty acid ester is, for example, 200 to 1,200.

[0047] The weight-average degree of polymerization (DPw) of the cellulose fatty acid ester is determined by the weight-average molecular weight (W １ ) by the molecular weight of the monomer unit.

[0048] When cellulose fatty acid ester is subjected to DSC measurement using the following temperature profile, a melting point peak appears in the temperature range of 100 to 160°C during the second heating process. Temperature profile: Heat from -80°C to 250°C at a rate of 20°C / min, cool from 250°C to -80°C at a cooling rate of 20°C / min, and then heat again from -80°C to 250°C at a heating rate of 20°C / min.

[0049] The ΔH (heat of fusion) at the melting point of the cellulose fatty acid ester (calculated from the peak area at the melting point) is, for example, 5.0 J / g or more and 20 J / g or less. From the viewpoint of improving thermal fluidity and impact resistance, the lower limit of ΔH is preferably 6.5 J / g, particularly preferably 10.0 J / g.

[0050] That is, the cellulose fatty acid ester has a melting point (Tm: °C) in the range of 100 to 160°C (the lower limit of the range is preferably 110°C, more preferably 120°C, particularly preferably 125°C, most preferably 130°C, and particularly preferably 135°C; the upper limit of the range is preferably 155°C, particularly preferably 150°C, and most preferably 145°C). The cellulose fatty acid ester exhibits excellent fluidity when heated at a temperature equal to or higher than the melting point.

[0051] The complex viscosity (Pa s) of the cellulose fatty acid ester at a temperature 30°C higher than the melting point (i.e., a temperature of the melting point (Tm: °C) + 30°C), a strain of 1.0%, and an angular frequency of 10 rad / s is, for example, 3000 or less, preferably 2000 or less, more preferably 1500 or less, even more preferably 1200 or less, particularly preferably 1000 or less, and most preferably 850 or less.

[0052] The complex viscosity (Pa s) of the cellulose fatty acid ester at 180 ° C, 1.0% strain, and an angular frequency of 10 rad / s is, for example, 1500 or less, preferably 1200 or less, more preferably 1000 or less, even more preferably 800 or less, and particularly preferably 700 or less. The complex viscosity (Pa s) of the cellulose fatty acid ester at 160 ° C, 1.0% strain, and an angular frequency of 10 rad / s is, for example, 3000 or less, preferably 2600 or less, more preferably 2500 or less, even more preferably 2000 or less, and particularly preferably 1500 or less. The complex viscosity (Pa s) of the cellulose fatty acid ester at 200 ° C, 1.0% strain, and an angular frequency of 10 rad / s is, for example, 450 or less, preferably 420 or less, more preferably 410 or less, and even more preferably 400 or less.

[0053] The complex viscosity can be determined by the method described in the examples.

[0054] Furthermore, by appropriately substituting the short-chain and long-chain fatty acid groups of the cellulose fatty acid ester, the interaction between the long-chain fatty acid groups is moderately alleviated, and a molded product (or solidified product) having high strength and excellent impact resistance can be formed. The Charpy impact strength (kJ / m) determined by the Charpy impact test described in the Examples can be obtained. ２ ) is, for example, 7 or more, preferably 10 or more, particularly preferably 16 or more, most preferably 18 or more, and particularly preferably 20 or more. The upper limit of the Charpy impact strength is, for example, 40.

[0055] (Method for Producing Cellulose Fatty Acid Esters) The cellulose fatty acid esters can be produced, for example, by the following methods. (1) A method of reacting cellulose acetate with a saturated fatty acid halide having 10 to 16 carbon atoms in the presence of a base such as pyridine. (2) A method of reacting cellulose acetate with a mixed acid anhydride formed from a saturated fatty acid having 10 to 16 carbon atoms and a haloacetic acid such as trifluoroacetic acid. (3) A method of reacting cellulose acetate with an anhydride of a saturated fatty acid having 10 to 16 carbon atoms. (4) A method of reacting cellulose acetate with a saturated fatty acid having 10 to 16 carbon atoms in the presence of a sulfonate. (5) A method of reacting cellulose acetate with a saturated fatty acid having 10 to 16 carbon atoms in the presence of a dehydration condensation agent. (6) A method of reacting cellulose with acetic anhydride and an anhydride of a saturated fatty acid having 10 to 16 carbon atoms. (7) A method of reacting cellulose with a mixed acid anhydride formed from acetic acid, a saturated fatty acid having 10 to 16 carbon atoms, and a haloacetic acid such as trifluoroacetic acid. (8) A method of reacting cellulose with acetic acid and a saturated fatty acid having 10 to 16 carbon atoms in the presence of a dehydration condensation agent, (9) A method of reacting cellulose acetate with a fatty acid chloride, and (10) A method of reacting cellulose with acetyl chloride and a fatty acid chloride.

[0056] [Thermoplastic Resin Composition, Molded Article, and Method for Producing Molded Article] The thermoplastic resin composition of the present disclosure contains one or more of the cellulose fatty acid esters as a plastic (i.e., a thermoplastic resin).

[0057] The thermoplastic resin composition contains a plastic, and the content of the plastic is, for example, 50% by weight or more, more preferably 60% by weight or more, particularly preferably 70% by weight or more, and most preferably 80% by weight or more of the total amount of the thermoplastic resin composition.

[0058] The thermoplastic resin composition may contain plastics other than the cellulose fatty acid ester as plastics, but from the viewpoint of increasing the proportion of biomass plastics and improving the greenhouse gas reduction effect, the proportion of the cellulose fatty acid ester relative to all plastics contained in the thermoplastic resin composition is preferably 30% by weight or more, more preferably 40% by weight or more, even more preferably 50% by weight or more, even more preferably 60% by weight or more, particularly preferably 70% by weight or more, and most preferably 80% by weight or more, the upper limit of which is 100% by weight.

[0059] The thermoplastic resin composition may contain a petroleum-derived plastic as a plastic other than the cellulose fatty acid ester, but from the viewpoint of improving the greenhouse gas reduction effect by increasing the content of biomass plastic, the proportion of petroleum-derived plastic to all plastics contained in the thermoplastic resin composition is preferably 70% by weight or less, more preferably 60% by weight or less, even more preferably 50% by weight or less, still more preferably 40% by weight or less, particularly preferably 30% by weight or less, and most preferably 20% by weight or less. The lower limit of this proportion is 0% by weight.

[0060] The thermoplastic resin composition may contain one or more other components in addition to the plastic, as needed, such as fillers, plasticizers, colorants, ultraviolet absorbers, light stabilizers, antioxidants, heat stabilizers, mold release agents, optical property adjusters, flame retardants, and fluorescent brighteners.

[0061] The thermoplastic resin composition can be produced by melt-kneading the thermoplastic resin composition with other components added as needed. For the melt-kneading, a kneader such as a twin-screw kneader can be used.

[0062] The shape of the thermoplastic resin composition is not particularly limited, and examples thereof include powder, particles, fibers, pellets, spheres (e.g., true spheres, nearly true spheres, ellipsoids), polyhedrons, rods (e.g., cylinders, prisms), plates, scales, and irregular shapes.

[0063] The thermoplastic resin composition melts when heated to a temperature above its melting point, rapidly reduces its viscosity, and exhibits excellent fluidity. Therefore, it is suitable as a resin composition for injection molding. The thermoplastic resin composition is also suitable as a raw material for paints, cosmetics, and personal care products.

[0064] The thermoplastic resin composition is melted, the viscosity of which is reduced, and the resulting composition is injected into a mold by injection molding, and then cooled and solidified to form a molded article (molded article of the thermoplastic resin composition) in which the shape of any mold is precisely transferred. Other methods that can be used to mold the thermoplastic resin composition include extrusion molding, blow molding, vacuum molding, and film molding.

[0065] The shape of the molded product is not particularly limited, and examples thereof include one-dimensional molded products such as fibers; two-dimensional molded products such as films; and three-dimensional molded products such as particles including pellets, tubes, and hollow cylinders.

[0066] The molded body is at least partially formed from the thermoplastic resin composition (more specifically, a solidified product of the thermoplastic resin composition), and may, if necessary, have a portion formed from a component other than the thermoplastic resin composition.

[0067] Examples of the molded article include 3D printers, straws, containers such as cups and bottles, shoe soles, films (e.g., polarizing plate protective films, retardation films, optical compensation films, anti-reflection films, color filters, photographic films, food films, etc.), packaging materials, electronic device housings, medical supplies, stationery, tubes, tapes, daily necessities, automobile parts, toys, etc.

[0068] [Thermoplastic Fiber] The thermoplastic fiber of the present disclosure contains one or more of the cellulose fatty acid esters as a plastic (i.e., a thermoplastic resin).

[0069] The thermoplastic fiber is a fibrous thermoplastic resin composition. Examples of the composition of the thermoplastic fiber include the same examples as those of the thermoplastic resin composition.

[0070] The method for producing the thermoplastic fiber is not particularly limited, and the thermoplastic fiber can be produced, for example, by melt spinning the thermoplastic resin composition (i.e., a method in which the thermoplastic resin composition is melted, extruded from a spinning nozzle, and cooled to form a fiber).

[0071] The thermoplastic fibers can be suitably used as materials for, for example, filters, nonwoven fabrics, clothing, sanitary materials (diapers, sanitary products), agricultural materials, medical supplies, and the like.

[0072] The above-described configurations and combinations thereof of the present disclosure are merely examples, and additions, omissions, substitutions, and modifications of the configurations are possible as appropriate without departing from the spirit of the present disclosure. Furthermore, each aspect disclosed in this specification can be combined with any other feature disclosed in this specification. Furthermore, the present disclosure is not limited by the embodiments, but is limited only by the claims.

[0073] The present disclosure will be explained in more detail below using examples, but the present disclosure is not limited to these examples.

[0074] Example 1 Using a 3 L separable flask equipped with a stirrer and a condenser, 30.00 g (0.185 mol) of regenerated cellulose (Tencel (registered trademark), manufactured by Fujibo Holdings Co., Ltd.) was added and dissolved in 1208.40 g of dimethylacetamide solution (lithium chloride concentration 6.7% by mass) containing dissolved lithium chloride under a nitrogen atmosphere to obtain a cellulose solution. 67.81 g (0.555 mol) of 4-dimethylaminopyridine was added thereto, and the liquid temperature was raised to 80 ° C. After which a mixture of 65.35 g (0.833 mol) of acetyl chloride and 182.13 g (0.833 mol) of lauric acid chloride was added dropwise to allow the reaction. After the reaction was allowed to proceed for 5 hours after the completion of the dropwise addition, a large amount of methanol was added to precipitate the product, which was then collected by filtration. The wet powder of the product obtained as a residue was added to a separable flask, 900.00 g (12.481 mol) of THF was added, and the mixture was heated to 60°C and stirred for 3 hours to redissolve, and a large amount of methanol was added again to precipitate the product. The precipitated product was recovered by filtration and then dried to obtain cellulose acetate laurate in which lauroyl groups and acetyl groups were substituted on the oxygen atoms of the cellulose skeleton.

[0075] Example 2 A cellulose fatty acid ester was obtained in the same manner as in Example 1, except that the reaction time was changed from 5 hours to 3 hours.

[0076] Example 3 A cellulose fatty acid ester was obtained in the same manner as in Example 1, except that a mixture of 87.13 g (1.110 mol) of acetyl chloride and 121.42 g (0.555 mol) of lauric acid chloride was used as the mixture of acetyl chloride and lauric acid chloride.

[0077] Example 4 A cellulose fatty acid ester was obtained in the same manner as in Example 1, except that a mixture of 43.56 g (0.555 mol) of acetyl chloride and 242.84 g (1.110 mol) of lauric acid chloride was used as the mixture of acetyl chloride and lauric acid chloride.

[0078] Comparative Example 1 A cellulose fatty acid ester was obtained in the same manner as in Example 2, except that a mixed solution of 108.91 g (1.388 mol) of acetyl chloride and 60.71 g (0.278 mol) of lauric acid chloride was used as the mixed solution of acetyl chloride and lauric acid chloride.

[0079] Comparative Example 2 A cellulose fatty acid ester was obtained in the same manner as in Example 2, except that a mixture of 21.78 g (0.278 mol) of acetyl chloride and 303.55 g (1.388 mol) of lauric acid chloride was used as the mixture of acetyl chloride and lauric acid chloride.

[0080] Comparative Example 3 A cellulose fatty acid ester was obtained in the same manner as in Example 1, except that 364.26 g (1.665 mol) of lauric acid chloride alone was used instead of the mixed solution of acetyl chloride and lauric acid chloride.

[0081] The melting point (Tm: °C) or glass transition temperature (Tg: °C), complex viscosity, and Charpy impact strength of the cellulose fatty acid esters obtained in the examples and comparative examples were measured by the following methods. The results are shown in Table 1 below and Figures 1 to 4.

[0082] (Measurement of melting point (Tm: °C) or glass transition temperature (Tg: °C)) A cellulose fatty acid ester was subjected to DSC measurement using the following temperature profile. If a peak appeared in the chart obtained during the second heating process, the temperature of the peak was taken as the melting point. ΔH was calculated from the peak area (the area surrounded by the baseline drawn around the peak). On the other hand, if the baseline of the chart shifted, the temperature of the intersection of the baseline and the tangent to the inflection point or the midpoint of the displacement was taken as the glass transition temperature. Temperature profile: The sample was heated from -80°C to 250°C at a rate of 20°C / min (first heating), cooled from 250°C to -80°C at a cooling rate of 20°C / min, and then heated again from -80°C to 250°C at a heating rate of 20°C / min (second heating).

[0083] (Measurement of Complex Viscosity) A film (0.3 mm thick) of cellulose fatty acid ester was prepared by melt press molding, and the change in complex viscosity of the obtained film was measured by temperature sweep at a fixed angular frequency using a rheometer. (Measurement conditions using a rheometer) Apparatus: Discovery HR20, manufactured by TA Instruments Jig: Parallel plate measuring jig Temperature control system: ETC (environmental test chamber) Purge gas: N ２ (10 L / min) Geometry: 25 mmφ disposable parallel plate Angular frequency: fixed at 10 rad / s Strain amount: 1.0% Temperature sweep rate: 5°C / min

[0084] (Measurement of Charpy Impact Strength) The cellulose fatty acid ester was molded using a HAAKE Minijet desktop injection molding machine manufactured by Thermofisher Scientific, with the cylinder temperature set to 180 to 220°C and the mold temperature set to 50°C. The Charpy impact strength was measured at a test temperature of 23°C in accordance with ISO179 / 1eA using a rectangular parallelepiped test piece (L x W x H = 80 mm x 10 mm x 4 mm) with a notch.

[0085]

[0086] As a result of the Charpy impact test, the notched portion of the test piece broke. In the case of the cellulose fatty acid ester of the example, the notched portion broke like a hinge (ductile fracture). On the other hand, in the case of the cellulose fatty acid ester of the comparative example, the notched portion broke completely (brittle fracture). From these results, it was found that the cellulose fatty acid ester of the present invention has excellent impact resistance.

[0087] In summary, the configuration of the present disclosure and its variations are described below. [1] A cellulose fatty acid ester in which the hydroxyl groups of cellulose are substituted with long-chain fatty acid ester groups and short-chain fatty acid ester groups, wherein the long-chain fatty acid ester groups are saturated fatty acid ester groups having 10 to 16 carbon atoms, the short-chain fatty acid ester groups are acetoxy groups, and the degree of substitution (DS) of the long-chain fatty acid ester groups is Ｌ ) and the degree of substitution of short-chain fatty acid ester groups (DSＳ ) satisfies the following formula (1) and formula (2): Ｌ +DS Ｓ ≧2.7 (1) 0.3≦DS Ｌ / DS Ｓ ≦5.0 (2) [2] The cellulose fatty acid ester according to [1], which has a complex viscosity of 1500 Pa s or less at a temperature of 180°C, a strain of 1.0%, and an angular frequency of 10 rad / s. [3] The cellulose fatty acid ester according to [1] or [2], which, when subjected to DSC measurement using the following temperature profile, exhibits a melting point peak in the temperature range of 100 to 160°C during the second heating process. Temperature profile: Heat from -80°C to 250°C at a rate of 20°C / min, cool from 250°C to -80°C at a cooling rate of 20°C / min, and then heat again from -80°C to 250°C at a heating rate of 20°C / min. [4] A thermoplastic resin composition comprising the cellulose fatty acid ester according to any one of [1] to [3]. [5] The thermoplastic resin composition according to [4], which is a resin composition for 3D printers. [6] The thermoplastic resin composition according to [4], which is a resin composition for injection molding. [7] A thermoplastic fiber comprising the cellulose fatty acid ester according to any one of [1] to [3]. [8] A molded article of the thermoplastic resin composition according to [4]. [9] A method for producing a molded article of the thermoplastic resin composition, comprising subjecting the thermoplastic resin composition according to [4] to injection molding.

Claims

1. A cellulose fatty acid ester in which the hydroxyl groups of cellulose are substituted with long-chain fatty acid ester groups and short-chain fatty acid ester groups, wherein the long-chain fatty acid ester groups are saturated fatty acid ester groups having 10 to 16 carbon atoms, the short-chain fatty acid ester groups are acetoxy groups, and the degree of substitution (DS) of the long-chain fatty acid ester groups is Ｌ ) and the degree of substitution of short-chain fatty acid ester groups (DS Ｓ ) satisfies the following formula (1) and formula (2): Ｌ +DS Ｓ ≧2.7 (1) 0.3≦DS Ｌ / DS Ｓ ≦5.0 (2) 2. The cellulose fatty acid ester according to claim 1, having a complex viscosity of 1500 Pa·s or less at a temperature of 180°C, a strain of 1.0%, and an angular frequency of 10 rad / s.

3. The cellulose fatty acid ester according to claim 1 or 2, wherein a melting point peak appears in the temperature range of 100 to 160°C during the second heating process when subjected to DSC measurement using the following temperature profile: Temperature profile: Heat from -80°C to 250°C at a rate of 20°C / min, cool from 250°C to -80°C at a cooling rate of 20°C / min, and then heat again from -80°C to 250°C at a heating rate of 20°C / min.

4. A thermoplastic resin composition comprising the cellulose fatty acid ester according to claim 1 or 2.

5. The thermoplastic resin composition according to claim 4, which is a resin composition for 3D printers.

6. The thermoplastic resin composition according to claim 4, which is a resin composition for injection molding.

7. A thermoplastic fiber comprising the cellulose fatty acid ester according to claim 1 or 2.

8. A molded article of the thermoplastic resin composition according to claim 4.

9. A method for producing a molded article, comprising subjecting the thermoplastic resin composition according to claim 4 to injection molding to obtain a molded article of said thermoplastic resin composition.

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