Cellulose ester resin composition, molded object, and method for producing the same.

Abstract

The present invention provides a cellulose ester resin composition used in a material extrusion method, wherein smoke generation is suppressed when the cellulose ester resin composition is extruded from the extruder. [Solution] A cellulose ester resin composition for use in a material extrusion method, comprising a cellulose ester resin and a polyvalent hydroxyl compound represented by the following general formula (1). H-(OE) n1 -O-C6H4-X-C6H4-O-(EO) n2 -H (1) [In general formula (1), C6H4 is a residue obtained by removing two hydrogen atoms from benzene, X is a methylene group or a dimethylmethylene group, E is an ethylene group, and n1 and n2 satisfy n1+n2=3 to 8, and are independently integers from 1 to 7.]

Description

[Technical Field]

[0001] This disclosure relates to cellulose ester resin compositions, molded objects, and methods for producing the same. [Background technology]

[0002] Cellulose is a plant-derived material that has been known for a long time and is known to possess mechanical properties equivalent to those of engineering plastics.

[0003] In recent years, the MEX method (Material Extrusion) has become known as a 3D printing (also called three-dimensional printing) method. Among the MEX methods, the FDM method (Fused Deposition Modeling) and the FGF method (Fused Granulate Fabrication) are attracting attention.

[0004] As an example of using cellulose derivatives in 3D printing materials, Patent Document 1 discloses, for example, "a 3D printing material containing 70-80% by mass of cellulose acetate and 20-30% by mass of a plasticizer." [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2024-43226 [Overview of the project] [Problems that the invention aims to solve]

[0006] As mentioned above, a known material for 3D printing is a material containing 70-80% by mass of cellulose acetate and 20-30% by mass of plasticizer.

[0007] The inventors of this disclosure attempted to use a cellulose ester resin composition having such a composition as a molding material for 3D printers. However, a problem arose in that smoke was emitted from the nozzle when the cellulose ester resin composition was extruded from the nozzle of the 3D printer's extruder. A small amount of smoke from the nozzle can be dealt with by installing a local exhaust system near the nozzle.

[0008] However, when printing large objects using a 3D printer, for example, it becomes necessary to move the nozzle for each extruder during the printing process. In other words, large objects cannot be manufactured using a method where the nozzle is fixed and the stage is moved. If this method is adopted, it is difficult to permanently install and move local exhaust equipment near the nozzle. Furthermore, if there is a lot of smoke coming from the extruder nozzle, liquefied material will adhere to various parts of the 3D printer's manufacturing equipment, causing various problems such as the material falling and contaminating the printed object. In the case of 3D printers, it is also possible to prevent delamination of large objects by increasing the extrusion temperature and lowering the viscosity of the resin, which also presents the problem of smoke generation being more likely.

[0009] The inventors of this disclosure have investigated and found that many of the substances causing such smoke are plasticizers contained in cellulose ester resin compositions. Because the plasticizers blended into cellulose ester resin compositions have low molecular weight and low melting point, they vaporize during the extrusion of the cellulose ester resin composition, generating smoke. The vaporized plasticizer then condenses into a liquid in the cooler areas around the extruder. Such liquid can mix with dust and other particles, becoming a contaminant and potentially dripping onto 3D printed objects.

[0010] This disclosure aims to provide a cellulose ester resin composition for use in material extrusion, wherein smoke generation is suppressed when the cellulose ester resin composition is extruded from the extruder. Furthermore, this disclosure aims to provide a method for producing the cellulose ester resin composition, a molded object containing the cellulose ester resin composition, and a method for producing the same. [Means for solving the problem]

[0011] The inventors of this disclosure have diligently studied to solve the above-mentioned problems. As a result, they have found that a cellulose ester resin composition containing a cellulose ester resin and a predetermined polyhydric hydroxyl compound suppresses smoke generation when the cellulose ester resin composition is extruded from the extruder when used in a material extrusion method.

[0012] This disclosure is the result of further consideration based on these findings. Specifically, this disclosure provides inventions in the following embodiments.

[0013] Item 1. A cellulose ester resin composition for use in a material extrusion method, comprising a cellulose ester resin and a polyvalent hydroxyl compound represented by the following general formula (1). H-(OE) n1 -O-C6H4-X-C6H4-O-(EO) n2 -H (1) [In general formula (1), C6H4 is a residue obtained by removing two hydrogen atoms from benzene, X is a methylene group or a dimethylmethylene group, E is an ethylene group, and n1 and n2 satisfy n1+n2=3 to 8, and are independently integers from 1 to 7.] Item 2. The cellulose ester resin composition according to Item 1, wherein the cellulose ester resin is cellulose acetate. Item 3. The cellulose ester resin composition according to item 1 or 2, wherein, when the total mass of the cellulose ester resin and the polyhydric hydroxyl compound represented by general formula (1) is 100% by mass, the proportion of the mass of the polyhydric hydroxyl compound represented by general formula (1) is 10 to 50% by mass. Item 4. The cellulose ester resin composition according to any one of items 1 to 3, wherein when the total mass of the cellulose ester resin and the polyhydric hydroxyl compound represented by general formula (1) is 100% by mass, the proportion of the mass of the cellulose ester resin is 50 to 90% by mass. Item 5. The cellulose ester resin composition according to any one of Items 1 to 4, having a pellet-like or filament-like shape. Item 6. A molding material for a 3D printer, comprising the cellulose ester resin composition according to any one of Items 1 to 5. Item 7. A molded object formed by molding the molding material for a 3D printer according to Item 6. Item 8. A method for manufacturing a molded object, comprising a step of molding the cellulose ester resin composition according to any one of Items 1 to 5. Item 9. A method for manufacturing a molded object using a 3D printer, wherein the 3D printer comprises a chamber, and in the chamber, a heatable base, an extrusion head, and a supply unit for a molding material for a 3D printer, and at least includes the method for manufacturing a molded object according to Item 8, wherein the supply unit for the molding material for a 3D printer supplies the molding material for a 3D printer according to Item 6. Item 10. The method for manufacturing a molded object according to Item 9, wherein the extrusion head has a screw structure inside it, and the extrusion head has a function of heating and melting the molding material for a three-dimensional printer. Item 11. A method for manufacturing a cellulose ester resin composition for use in a material extrusion method, comprising a step of melt-kneading a raw material composition containing a cellulose ester resin and a polyhydric hydroxyl compound represented by the following general formula (1). H-(OE) n1 -O-C6H4-X-C6H4-O-(EO) n2 -H (1) [In the general formula (1), C6H4 is a residue obtained by removing two hydrogen atoms from benzene, X is a methylene group or a dimethylmethylene group, E is an ethylene group, n1 and n2 satisfy n1 + n2 = 3 to 8, and are each independently an integer of 1 to 7.]

Advantages of the Invention

[0014] This disclosure provides a cellulose ester resin composition for use in material extrusion, wherein smoke generation is suppressed when the cellulose ester resin composition is extruded from the extruder. Furthermore, this disclosure provides a method for producing the cellulose ester resin composition, a molded product containing the cellulose ester resin composition, and a method for producing the same. Moreover, it is possible to manufacture large molded products with high interlayer adhesion strength. [Modes for carrying out the invention]

[0015] Each configuration and its combination in each embodiment is an example, and additions, omissions, substitutions, and other modifications can be made as appropriate without departing from the spirit of this disclosure. This disclosure is not limited by the embodiments.

[0016] In the numerical ranges described in stages in this disclosure, the upper or lower limit stated in one numerical range may be replaced with the upper or lower limit of another numerical range described in stages. Alternatively, the upper and lower limits, upper and lower limits, or lower and lower limits described separately may be combined to form numerical ranges. Furthermore, in the numerical ranges described in this disclosure, the upper or lower limit stated in one numerical range may be replaced with the values ​​shown in the examples.

[0017] Furthermore, in this disclosure, the cellulose ester resin composition includes raw materials (such as filaments and pellets described later) for supplying the cellulose ester resin composition to a material extrusion method (such as a method using a 3D printer), and the molded product of the cellulose ester resin composition includes a molded product obtained by fabricating the cellulose ester resin composition using a 3D printer.

[0018] [Cellulose ester resin composition] The cellulose ester resin composition of this disclosure is a resin composition comprising at least a cellulose ester resin and a polyhydric hydroxyl compound represented by general formula (1), as described later.

[0019] (Cellulose ester) The cellulose ester resin contained in the cellulose ester resin composition of this disclosure may be any cellulose ester resin that is known.

[0020] Specific examples of cellulose ester resins include cellulose fatty acid esters (cellulose acetate, cellulose propionate, cellulose butyrate, cellulose acetate propionate, and cellulose acetate butyrate, etc.), partially alkylated cellulose fatty acid esters in which some of the hydroxyl groups of cellulose are substituted with alkyl groups (methylcellulose acetate, ethylcellulose acetate, and propylcellulose acetate, etc.), hydroxyalkoxycellulose fatty acid esters in which some of the hydroxyl groups of cellulose are substituted with hydroxyalkoxy groups (hydroxyethylcellulose acetate and hydroxypropylcellulose acetate, etc.), and polyester grafted cellulose esters (polycaprolactone grafted cellulose acetate, etc.). The cellulose ester resin contained in the cellulose ester resin composition of this disclosure may be one type or two or more types.

[0021] Among these cellulose ester resins, cellulose fatty acid esters are preferred, and cellulose acetate is more preferred, because they are suitable for use in material extrusion methods.

[0022] Cellulose acetate is cellulose ((C6H 10 O5) n At least some of the hydrogen atoms of the hydroxyl group contained in ) are substituted with acetyl groups. That is, the cellulose acetate according to this disclosure has polymerization units represented by the following general formula (A).

[0023] [ka]

[0024] In the above formula (A), R 1 , R 2 and R 3 each independently represent a hydrogen atom or an acetyl group. However, at least one of R 1 , R 2 and R 3 is an acetyl group.

[0025] In the cellulose ester resin composition of the present disclosure, the content of the cellulose ester resin is preferably 50% by mass or more, more preferably 60% by mass or more, still more preferably 70% by mass or more, and is preferably 90% by mass or less, more preferably 80% by mass or less. Preferred ranges include about 50 to 90% by mass, about 50 to 80% by mass, about 60 to 90% by mass, about 60 to 80% by mass, about 70 to 90% by mass, about 70 to 80% by mass, and the like. When the mass ratio of the cellulose ester resin is 90% by mass or less, the plasticity is good, and when it is 50% by mass or more, the mechanical properties of the molded product are good.

[0026] (Total degree of acetyl substitution) When the cellulose ester resin contains cellulose acetate, the total degree of acetyl substitution of cellulose acetate is preferably 2.7 or less, more preferably 1.8 to 2.6, still more preferably from 2.1 to 2.5, and even more preferably from 2.2 to 2.5. If the total degree of acetyl substitution is within the above range, the intermolecular interaction of cellulose acetate is not excessively strengthened, and the melt fluidity of the cellulose ester resin composition can be improved favorably. When the total degree of acetyl substitution of cellulose acetate exceeds 2.6, the melt fluidity of the cellulose ester resin composition decreases. On the other hand, when the total degree of acetyl substitution of cellulose acetate is less than 1.8, the water affinity of the cellulose ester resin composition increases, and the weather resistance of the molded product of the cellulose ester resin composition deteriorates.

[0027] The total degree of acetyl substitution can be determined by converting the degree of acetic acid, which is calculated according to the measurement method for the degree of acetic acid in ASTM:D-817-91 (Test methods for cellulose acetate, etc.), using the following formula. This is the most common method for determining the total degree of acetyl substitution in cellulose acetate. DS=162.14×AV×0.01 / (60.052-42.037×AV×0.01) DS: Degree of total acetyl substitution AV: Degree of acetic acid (%)

[0028] First, 500 mg of dried cellulose acetate (sample) is accurately weighed and dissolved in 50 ml of a mixed solution of ultrapure water and acetone (volume ratio 4:1). Then, 50 ml of 0.2 N sodium hydroxide aqueous solution is added, and saponification is carried out at 25°C for 2 hours. Next, 50 ml of 0.2 N hydrochloric acid is added, and the amount of acetic acid removed is titrated with 0.2 N sodium hydroxide aqueous solution (0.2 N sodium hydroxide normal solution) using phenolphthalein as an indicator. A blank test (test without a sample) is also performed using the same method. Finally, the AV (degree of acetate) (%) is calculated according to the following formula. AV(%) = (AB) × F × 1.201 / Sample weight (g) A: Titration volume (ml) of 0.2N sodium hydroxide normal solution B: Titration volume (ml) of 0.2N sodium hydroxide normal solution in the blank test. F: Factor of 0.2N sodium hydroxide normal solution

[0029] In this disclosure, cellulose acetate exhibits thermoplasticity and is suitable for molding because, as described above, at least a portion of the hydroxyl groups of the β-glucose ring are esterified with acetyl groups. Furthermore, in this disclosure, cellulose acetate can exhibit excellent strength and heat resistance when used to form molded objects. Moreover, since cellulose is a completely plant-derived component, it significantly reduces the environmental impact.

[0030] In this disclosure, the molecular weight of cellulose acetate may be in the range of 5,000 to 1,000,000 if it is the number average molecular weight (Mn), more preferably in the range of 10,000 to 500,000, and even more preferably in the range of 100,000 to 200,000. The weight average molecular weight (Mw) is 400,000 or less, more preferably in the range of 160,000 to 380,000, and even more preferably in the range of 230,000 to 360,000. By setting the weight average molecular weight and number average molecular weight within this range, the melt-flowability of the cellulose ester resin composition can be improved, as well as the moldability and mechanical strength of the molded product of the cellulose ester resin composition. If the weight average molecular weight of cellulose acetate falls below the above lower limit, the molded product of the cellulose ester resin composition may become brittle.

[0031] Furthermore, the molecular weight distribution (Mw / Mn) of the cellulose acetate may be in the range of 2.2 to 3.5, and preferably in the range of 2.4 to 3.2. A molecular weight distribution within this range improves the melt-flow properties of the cellulose ester resin composition and enhances the moldability of the molded product. When the Mw / Mn ratio of the cellulose acetate exceeds the above upper limit, there is a tendency for a higher proportion of gel-like material to be produced.

[0032] In this disclosure, it is preferable to use cellulose acetate having a predetermined total acetyl substitution degree and a molecular weight within the above range in order to improve the melt fluidity of the cellulose ester resin composition. Since it is difficult to lower the degree of polymerization of cellulose acetate while maintaining the total acetyl substitution degree of cellulose acetate, if a cellulose raw material that is originally of low polymerization is used, it is possible to obtain a cellulose acetate of low polymerization while obtaining the desired degree of substitution. In order to obtain a cellulose acetate of low polymerization, it is preferable to use cellulose with a predetermined sugar composition ratio, as described later.

[0033] In this disclosure, the number-average molecular weight (Mn), weight-average molecular weight (Mw), and molecular weight distribution (Mw / Mn) are determined by size exclusion chromatography (GPC) measurement using the following apparatus and conditions (GPC-light scattering method). Equipment: High-performance liquid chromatography (Shimadzu LC-20A) Solvent: 10 mM LiBr acetone Column: Plgel 5μm MIXED-C + Plgel 5μm MIXED-D + Guard column 5μm Flow rate: 0.8ml / min Temperature: 35℃ Sample concentration: 0.5 wt% Injection volume: 50μl Detection: Shimadzu RID-10A Standard material for MALLS correction: EasiVial PM (PMMA)

[0034] (pulp) Pulp can be used as a cellulose source for the cellulose ester resin of this disclosure. Examples of pulp include wood pulp and linter pulp. In particular, wood pulp can be used.

[0035] Examples of wood pulp include coniferous pulp and hardwood pulp. Examples of coniferous pulp include pulp obtained from spruce, pine, and boxwood. Examples of hardwood pulp include eucalyptus and acacia. The pulp may be used alone or in combination of two or more types; for example, coniferous pulp and hardwood pulp may be used in combination.

[0036] (Method for producing cellulose ester resin) Examples of methods for producing cellulose acetate include a pretreatment step (1) in which pulp is brought into contact with acetic acid, a step (2) in which the cellulose contained in the pulp is reacted with acetic anhydride after the pretreatment to acetylate it, a step (3) in which the cellulose acetate obtained by acetylation is hydrolyzed, and a step (4) in which the cellulose acetate whose degree of acetyl substitution has been adjusted by the hydrolysis is precipitated. Known conditions can be used for each of the above steps.

[0037] [Polyhydric hydroxyl compounds] The polyhydric hydroxyl compound contained in the cellulose ester resin composition is a compound represented by the following general formula (1). H-(OE) n1 -O-C6H4-X-C6H4-O-(EO) n2 -H (1)

[0038] The polyhydric hydroxyl compound represented by general formula (1) functions as a plasticizer in the cellulose ester resin composition of this disclosure to enhance the moldability of the cellulose ester resin.

[0039] In general formula (1), C6H4 is a residue obtained by removing two hydrogen atoms from benzene. Here, the two hydroxyl groups to be removed can be any of the six hydrogen atoms that benzene has, preferably the two hydrogen atoms at positions 1 and 3, or the two hydrogen atoms at positions 1 and 4, and more preferably the two hydrogen atoms at positions 1 and 4. Furthermore, it is preferable that the positions of the two hydrogen atoms are the same in the two C6H4 components included in general formula (1).

[0040] Furthermore, in general formula (1), X is a methylene group or a dimethylmethylene group, with the dimethylmethylene group being more preferred.

[0041] In general formula (1), E is an ethylene group.

[0042] In general formula (1), n1 and n2 satisfy n1+n2=3 to 8. Also, n1 and n2 are independent integers from 1 to 7. n1+n2 is preferably from 4 to 6, and each is independently an integer from 1 to 5, and it is even more preferable that n1+n2 is from 4 to 6, and each is independently an integer from 2 to 4.

[0043] The polyhydric hydroxyl compound represented by general formula (1) preferably has a hydroxyl value of 200 to 340 mgKOH / g, and more preferably 220 to 320 mgKOH / g. The hydroxyl value is measured in accordance with JIS K1557-1.

[0044] Polyvalent hydroxyl compounds represented by general formula (1) can be prepared, for example, by adding ethylene oxide to bisphenol-type compounds [such as 2,2-bis(4-hydroxyphenyl)propane and bis(4-hydroxyphenyl)methane] using known methods described in Japanese Patent Publication No. 6-184301 and Japanese Patent Publication No. 2000-086562.

[0045] From the viewpoint of more favorably exhibiting the effects of the invention disclosed herein, the polyhydric hydroxyl group compound represented by general formula (1) is preferably a polyhydric hydroxyl group compound obtained by adding 3 to 8 moles of ethylene oxide to 1 mole of bisphenol A, and more preferably a polyhydric hydroxyl group compound obtained by adding 4 to 6 moles of ethylene oxide to 1 mole of bisphenol A.

[0046] From the viewpoint of more favorably exhibiting the effects of the invention disclosed herein, the polyhydric hydroxyl compound represented by general formula (1) is preferably 330 to 600 in chemical formula weight, and more preferably 350 to 500.

[0047] From the viewpoint of more favorably exhibiting the effects of the invention disclosed herein, the solubility parameter (SP value) of the polyhydric hydroxyl compound represented by general formula (1) is 11.2 to 12.7 (cal / cm³). 3 Preferably 1 / 2, and 11.3~12.3 (cal / cm 3It is even more preferable that the ratio is 1 / 2. By setting n1 and n2 in general formula (1) to predetermined ranges, the solubility parameters of polyhydric hydroxyl compounds can be adjusted to a preferred range.

[0048] In this disclosure, the solubility parameter of polyhydric hydroxyl compounds refers to the value calculated using formula (28) on page 153 of the Fedors method (Polymer Engineering and Science, February, 1974, Vol. 14, No. 2, pp. 147-154), using the numerical values ​​(heat of vaporization and molar volume of atoms or functional groups at 25°C) listed on page 152 (Table 5).

[0049] Specifically, the solubility parameters of polyhydric hydroxyl compounds can be calculated by applying the values ​​corresponding to the types of atoms and atomic groups in the molecular structure, taken from the Δei and vi values ​​listed in Table 1 below, which are parameters of the Fedors method, to the following formula. Formula: SP value = (ΣΔei / Σvi)¹ / ²

[0050] [Table 1]

[0051] In this disclosure, the polyhydric hydroxyl compound represented by general formula (1) may be a polyhydric hydroxyl compound available on the market, for example, the Newpol BPE series manufactured by Sanyo Chemical Industries, Ltd., the AE series manufactured by Meiwa Chemical Industries, Ltd., and EO-based BA glycol manufactured by Nippon Emulsifier Co., Ltd. can be used.

[0052] The polyhydric hydroxyl compound represented by general formula (1) contained in the cellulose ester resin composition of this disclosure may be one type or two or more types.

[0053] In the cellulose ester resin composition of this disclosure, when the total mass of the cellulose ester resin and the polyhydric hydroxyl compound represented by general formula (1) is 100% by mass, the mass percentage of the cellulose ester resin is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, and also preferably 90% by mass or less, more preferably 80% by mass or less. Preferred ranges include approximately 50-90% by mass, approximately 50-80% by mass, approximately 60-90% by mass, approximately 60-80% by mass, approximately 70-90% by mass, and approximately 70-80% by mass. When the mass percentage of the cellulose ester resin is 90% by mass or less, plasticity is good, and when it is 50% by mass or more, the mechanical properties of the molded product are good.

[0054] Furthermore, in the cellulose ester resin composition of this disclosure, when the total mass of the cellulose ester resin and the polyhydric hydroxyl compound represented by general formula (1) is 100% by mass, the mass ratio of the polyhydric hydroxyl compound represented by general formula (1) is preferably 10% by mass or more, more preferably 20% by mass or more, and also preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less. Preferred ranges include approximately 10-50% by mass, approximately 10-40% by mass, approximately 10-30% by mass, approximately 20-50% by mass, approximately 20-40% by mass, and approximately 20-30% by mass. When the mass ratio of the polyhydric hydroxyl compound is 10% or more, the plasticity (moldability) of the cellulose ester resin composition of this disclosure is good, and when it is 50% by mass or less, smoke emission from the extruder is more preferably suppressed.

[0055] (Additives) The cellulose ester resin composition of this disclosure may contain additives such as plasticizers other than polyhydric hydroxyl compounds represented by general formula (1) (hereinafter referred to as "other plasticizers"), glass-based inorganic fillers, stabilizers (e.g., antioxidants, ultraviolet absorbers, heat stabilizers, light-resistant stabilizers, etc.), colorants (dyes, pigments, etc.), antistatic agents, flame retardant aids, lubricants, antiblocking agents, dispersants, fluidizers, dripping inhibitors, antibacterial agents, and other components, to the extent that they do not impair its performance. The cellulose ester resin composition of this disclosure may contain only one type of additive or two or more types.

[0056] (Other plasticizers) Other plasticizers include aromatic carboxylic acid esters [dialkyl phthalates such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, and di-2-ethylhexyl phthalate (alkyl group with 1 to 12 carbon atoms, hereafter "C" will be used to represent "C"); alkoxy phthalates such as dimethoxyethyl phthalate (alkoxy group with 1 to 6 carbon atoms) (C1 to 12); alkyl aryl (C1 to 12) phthalates such as butyl benzyl phthalate (C1 to 3); alkylphthalyl (C1 to 6) alkylene glycolates such as ethyl phthalyl ethylene glycolate and butyl phthalyl butylene glycolate (C2 to 4); trialkyl trimellitates such as trimethyl trimellitate, triethyl trimellitate, trioctyl trimellitate, and tri-2-ethylhexyl trimellitate (C1 to 12); pyromellitate such as tetraoctyl pyromellitate] Examples of known plasticizers include tetraalkyl meritol esters (C1-C12, etc.), fatty acid esters [adipate esters such as dibutyl adipate, dioctyl adipate, butoxyethoxyethyl benzyl adipate and dibutoxyethoxyethyl adipate, azelaic acid esters such as diethyl azelaate, dibutyl azelaate and dioctyl azelaate, sebacate esters such as dibutyl sebacate and dioctyl sebacate, butyl oleate and methylacetyl ricinoleate, etc.], lower fatty acid esters of polyhydric alcohols (glycerin, trimethylolpropane, pentaerythritol and sorbitol, etc.) [such as diglycerin tetraacetate], glycol esters (such as dipropylene glycol dibenzoate), citrate esters [such as acetyl tributyl citrate], amides [such as N-butylbenzenesulfonamide], and ester oligomers (such as caprolactone oligomers).

[0057] (Glass-based inorganic filler) The cellulose ester resin composition of this disclosure may contain a glass-based inorganic filler. By incorporating a glass-based inorganic filler into the cellulose ester resin composition, the difference in refractive index between cellulose acetate and the glass-based inorganic filler can enhance the aesthetic appeal of the molded object made from the cellulose ester resin composition. Examples of glass-based inorganic fillers include glass fibers, glass flakes, and glass beads, with the use of glass beads being preferable.

[0058] The blending ratio of the glass-based inorganic filler is preferably 0 to 30 parts by mass, more preferably 2 to 20 parts by mass, and more preferably 5 to 10 parts by mass, per 100 parts by mass of the cellulose ester resin composition.

[0059] When glass fibers are used as a glass-based inorganic filler, their shape is not particularly limited, but for example, the average length can be 100 μm to 5 mm, more preferably 500 μm to 3 mm, and the average diameter can be 1 to 50 μm, more preferably 3 to 30 μm. When glass flakes or glass beads are used, their average particle size is also not particularly limited, but for example, it can be 0.1 to 100 μm, more preferably 0.1 to 50 μm. These glass-based inorganic fillers can be used individually or in combination of two or more.

[0060] The above-mentioned "average length," "average diameter," and "average particle size" can be calculated by heating the cellulose ester resin composition at 600°C for 2 hours to ash it and obtain an ashing residue, then analyzing images of this ashing residue taken with a CCD camera (for example, PITA-3, a dynamic image analysis / particle (state) analyzer manufactured by Seishin Corporation) and calculating the weighted average.

[0061] (Stabilizer) Stabilizers include antioxidants, UV absorbers, heat stabilizers, lightfasteners, and colorants. Examples of antioxidants among stabilizers include cyclic neopentanetetraylbis(octadecyl) phosphite, cyclic neopentanetetraylbis(2,4-di-t-butylphenyl) phosphite, cyclic neopentanetetraylbis(2,6-di-t-butyl-4-methylphenyl) phosphite, 2,2-methylenebis(4,6-di-t-butylphenyl)octyl phosphite, and tris(2,4-di-t-butylphenyl) phosphite.

[0062] Among stabilizers, benzotriazole-based UV absorbers can be cited as examples of UV absorbers.

[0063] The proportion of these stabilizers can be 0.05 to 1 part by mass per 100 parts by mass of cellulose acetate, preferably 0.1 to 0.8 parts by mass, and more preferably 0.15 to 0.5 parts by mass.

[0064] (Other ingredients) Other additives that may be included in the cellulose ester resin composition of this disclosure include, for example, alicyclic epoxy compounds, specifically, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexylcarboxylate, flexible alicyclic epoxy resins, alicyclic epoxy diluents, alicyclic monoepoxides having vinyl groups, polyfunctional alicyclic epoxy resins, alicyclic solid epoxy resins, and the like.

[0065] Examples of 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexylcarboxylate include Daicel Corporation's product names Celoxide 2021 (epoxy equivalent 128-145), Celoxide 2021A (epoxy equivalent 130-140), and Celoxide 2021P (epoxy equivalent 128-145); an example of a flexible alicyclic epoxy resin is Daicel Corporation's product name Celoxide 2081 (epoxy equivalent 190-210); an example of an alicyclic epoxy diluent is Daicel Corporation's product name Celoxide 3000 (epoxy equivalent <93.5); vinyl group Examples of alicyclic monoepoxides include Daicel Corporation's product name Celoxide 2000 (epoxy equivalent 110-130), examples of polyfunctional alicyclic epoxy resins include Daicel Corporation's product names Epolid GT301 (epoxy equivalent 200-220), Epolid GT302 (epoxy equivalent 220-280), Epolid GT401 (epoxy equivalent 210-235), and Epolid GT403 (epoxy equivalent 270-300), and an example of alicyclic epoxy solid resin is Daicel Corporation's product name EHPE (epoxy equivalent 170-190). When adding an alicyclic epoxy compound, 0.1 to 1 part by mass can be added per 100 parts by mass of cellulose acetate, preferably 0.2 to 0.8 parts by mass, and more preferably 0.3 to 0.7 parts by mass.

[0066] From the viewpoint of more favorably exhibiting the effects of the invention disclosed herein, the total mass ratio of the aforementioned additives (i.e., plasticizers (hereinafter referred to as other plasticizers), glass-based inorganic fillers, stabilizers (e.g., antioxidants, ultraviolet absorbers, heat stabilizers, light-resistant stabilizers, etc.), colorants (dyes, pigments, etc.), antistatic agents, flame retardant aids, lubricants, antiblocking agents, dispersants, fluidizers, dripping inhibitors, antibacterial agents, and other components, etc.) is such that, when the total mass of the cellulose ester resin and the polyhydric hydroxyl compound represented by general formula (1) is taken as 100% by mass, the upper limit is, for example, 35% by mass or less, 30% by mass or less, 25% by mass or less, 20% by mass or less, 15% by mass or less, 10% by mass or less, 5% by mass or less, 1% by mass or less, etc., and the lower limit is 0% by mass or more, 1% by mass or more, 5% by mass or more, etc.

[0067] (Water content of cellulose ester resin composition) The water content of the cellulose ester resin composition of this disclosure is preferably 0.1 to 0.4% by mass relative to the total amount of the composition. Having a water content within this range helps to suppress problems such as non-adhesion between layers, and suppresses foaming caused by high water content, thereby maintaining transparency. To adjust the water content of the cellulose ester resin composition to the above range, the resin temperature in the melt-mixing conditions when preparing the cellulose ester resin composition may be, for example, 210 to 260°C, preferably 215 to 255°C, typically 230 to 250°C. The resin temperature may be the resin temperature at the die. This can be achieved by drying the prepared cellulose ester resin composition with dehumidified air at approximately 80 to 95°C, typically 90°C, or by using cellulose acetate with a pre-adjusted water content. Furthermore, the water content of the cellulose ester resin composition with its water content adjusted to the above range can be maintained by packaging it with a moisture-proof packaging material described later.

[0068] The water content of the cellulose ester resin composition is measured by the Karl Fischer method in accordance with JIS K 7251.

[0069] (Melt flow rate of cellulose ester resin composition) The melt flow rate (hereinafter also referred to as MFR) (weight of resin flowing out in 10 minutes at 220°C and a load of 10 kg (g / 10min)) of the cellulose ester resin composition of this disclosure, in accordance with ISO 1133, is preferably 20 or higher, more preferably 40 or higher, and even more preferably 50 or higher. A high MFR of the cellulose ester resin composition indicates high melt fluidity of the cellulose ester resin composition. There is no particular upper limit to the MFR (220°C and a load of 10 kg for 10 minutes), and even if the MFR is too high to be measured (no measurement value can be obtained), it is still useful as the cellulose ester resin composition of this disclosure. On the other hand, the range of the MFR (190°C and a load of 10 kg for 10 minutes) is preferably 11 or higher, more preferably 13 or higher, and even more preferably 15 or higher. On the other hand, there is no particular upper limit to the MFR. The MFR can be adjusted, for example, by adjusting the physical properties of the cellulose ester resin (total degree of substitution, weight-average molecular weight, Mw / Mn ratio) as described above.

[0070] (Shape of cellulose ester resin composition) Examples of the cellulose ester resin composition of this disclosure include pellets and filaments (lobes). Such shapes are suitable for materials used in material extrusion (MEX).

[0071] The pelletized cellulose ester resin composition is in a form that can be easily applied to the FGF method (using a screw-type extrusion head) described later. If L is the length of the longest part of the particles constituting the pellet, and D is the diameter of the largest circumscribed circle on a plane perpendicular to the longest part, then L / D is, for example, 1 to 10, and preferably 1 to 5. L is, for example, 0.5 to 10 mm, preferably 1 to 6 mm, and more preferably 2 to 4 mm. Specifically, L / D is, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10, and may be within the range of any two of the values ​​exemplified here. Specifically, L is, for example, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 mm, and may be within the range of any two of the values ​​exemplified here.

[0072] The filamentous cellulose ester resin composition is in a form that can be easily applied to the FDM method. The filamentous cellulose ester resin composition is preferably obtained by melt-extruding the cellulose ester resin composition, then cooling and solidifying it in air or water to form monofilament threads with a diameter of preferably 1.65 to 3.00 mm, and more specifically, monofilament threads with a diameter of 1.65 to 1.85 mm or 2.70 to 2.90 mm.

[0073] (Color system of cellulose ester resin composition) The cellulose ester resin composition disclosed herein can be highly transparent and colorless. Furthermore, it is possible to impart a desired color by adding an appropriate coloring agent.

[0074] The L color of a cellulose ester resin composition without added colorants, expressed in the Lab color space (JIS Z 8781-4). * The range of values ​​is 93 to 96, and preferably 94 to 95. Also, a * The range of values ​​is -1.0 to 1.0, and preferably -0.7 to 0.0. Also, b * The range of values ​​is 0.0 to 5.0, and preferably 1.0 to 4.0.

[0075] The hue color system for cellulose ester resin compositions is CIE1976 L * a * b * The following is used: The measurement method uses a Konica Minolta CM-3600A spectrophotometer and a Kurabo AUCOLOR-VP10 computer color matching system for plastics as the measurement program to measure transmittance.

[0076] (Moisture-proof packaging material) The cellulose ester resin composition of this disclosure is preferably packaged in a moisture-proof packaging material. The cellulose ester resin composition packaged in the moisture-proof packaging material may be in the form of pellets, filaments, or other shapes. By packaging the cellulose ester resin composition in a moisture-proof packaging material, it is possible to prevent the water content of the cellulose ester resin composition from changing in response to the amount of moisture in the atmosphere, and consequently, to prevent discoloration of the cellulose ester resin composition.

[0077] Examples of moisture-proof packaging materials include those made from materials with gas barrier properties, specifically gas barrier films, aluminum foil, or metal-deposited films such as aluminum or silica. Examples of substrates for gas barrier films and metal-deposited films include polyethylene terephthalate, biaxially oriented nylon, biaxially oriented polypropylene, unoriented polypropylene, and OPCP laminate film.

[0078] (Application) The cellulose ester resin composition of this disclosure suppresses smoke generation when the cellulose ester resin composition is extruded from the extruder when used in a material extrusion method. For this reason, the cellulose ester resin composition of this disclosure is suitably used as a material for material extrusion (hereinafter sometimes referred to as a material for material extrusion). Furthermore, the material for material extrusion can be used as a molding material for 3D printers.

[0079] When the cellulose ester resin composition disclosed herein is used as a material for material extrusion and further used as a molding material for 3D printers, various large-scale molded objects can be produced. Specific examples of molded objects include building components.

[0080] [Method for producing cellulose ester resin composition] The cellulose ester resin composition of this disclosure can be produced by mixing at least a cellulose ester resin and a polyhydric hydroxyl compound represented by the general formula (1) as raw materials.

[0081] The cellulose ester resin composition of this disclosure can be suitably produced by a method that includes a step of melt-kneading a raw material composition comprising at least a cellulose ester resin and a polyvalent hydroxyl compound represented by the general formula (1).

[0082] More specifically, a method for producing the cellulose ester resin composition of this disclosure includes, at a minimum, mixing a cellulose ester resin, a polyvalent hydroxyl compound represented by general formula (1), and additives used as needed using a known mixer such as a tumbler mixer, a Henschel mixer, and a ribbon mixer, and then melt-kneading the mixture at 200°C to 300°C using a known extruder such as a single-screw or twin-screw extruder, or a known kneader such as a heated roll or a Banbury mixer.

[0083] There are no restrictions on the mixing order of the cellulose ester resin and the polyhydric hydroxyl compound represented by general formula (1), and any additives used as needed. One method involves pre-mixing the cellulose ester resin and the polyhydric hydroxyl compound represented by general formula (1), and any additives used as needed, all together, and then kneading them.

[0084] Furthermore, the method for producing the cellulose ester resin composition of this disclosure may further include a step of drying the cellulose ester resin composition after the above-mentioned melt-kneading.

[0085] As a drying method, one method is to dry the compound with dehumidified air at approximately 80-95°C, typically at 90°C. Subsequently, the resulting compound is extruded into strands using a twin-screw extruder or the like, and by using methods such as air cutting as needed, a pelletized or filamentous cellulose ester resin composition is obtained.

[0086] The mixing ratio of each component in the raw material composition can be the same as that described above for each component. Furthermore, there are no particular restrictions on the method of adding other additives as long as they are added before the melt-mixing process, and known equipment and operations can be used in appropriate combinations. In addition, in order to bring the water content of the cellulose ester resin composition within a predetermined range, it is preferable to adjust the melt-mixing conditions of the composition as described above, or to go through a drying process using dehumidified air.

[0087] [Method for manufacturing molded objects using cellulose ester resin composition (material for material extrusion)] The method for manufacturing a molded object according to this disclosure is a method for manufacturing a molded object that includes the step of molding the cellulose ester resin composition according to this disclosure.

[0088] More specifically, when the cellulose ester resin composition of this disclosure is used as a material for material extrusion, various objects can be fabricated using a 3D printer. Examples of material extrusion methods include the FDM method (Fused Deposition Modeling) and the FGF method (Fused Granulate Fabrication). The cellulose ester resin composition of this disclosure can be suitably used in either of these methods, and is particularly suitable for use in the FGF method.

[0089] Gantry-type 3D printers used in material extrusion generally have a chamber containing a heatable substrate, an extrusion head mounted on the gantry structure, a heating and melting device, and, if necessary, a material supply unit such as a guide for the material extrusion material (filament) and a material extrusion material cartridge mounting section. Some 3D printers have an extrusion head with a heating and melting function.

[0090] In a gantry-type 3D printer, the extrusion head is mounted in a gantry structure, allowing it to be moved arbitrarily on the XY plane of the substrate. The substrate is the platform for constructing the desired three-dimensional object or support material, and it is preferable that it be designed to allow for heating and maintaining temperature to improve adhesion with the layered material and to improve the dimensional stability of the resulting resin object as the desired three-dimensional object. Typically, at least one of the extrusion head and the substrate is movable in the Z-axis direction perpendicular to the XY plane.

[0091] For material extrusion, the material is supplied from the raw material supply unit to the extrusion head. If the material is in the form of a filament, it is fed into the extrusion head by a pair of opposing rollers or gears (FDM method). On the other hand, if the material is in the form of a pellet, it is supplied via a hopper into an extrusion head (generally called a miniature extrusion molding machine) that has a heating and melting function and an internal screw structure (FGF method).

[0092] In both FDM and FGF methods, the material for material extrusion is heated and melted in the extrusion head and extruded from the nozzle at the tip of the extrusion head. For example, based on a signal transmitted from a CAD model, the extrusion head moves its position while supplying the material extrusion onto the substrate and depositing layers. After this process is complete, the deposited material can be removed from the substrate, and support materials and other parts can be removed or excess parts removed as needed to obtain the desired 3D object.

[0093] When using the cellulose ester resin composition of this disclosure, it is preferable to use the FGF method, which allows for a large amount of material to be extruded and enables the production of large objects in a short time. In this case, the cellulose ester resin composition is used in pellet form. The pelletized cellulose ester resin composition of this disclosure can be used not only in the gantry-type 3D printer described above, but also in a robotic arm-type large 3D printer equipped with a small extrusion molding machine used in the FGF method as the extrusion head.

[0094] On the other hand, in the FDM method, it is common to engage the material for material extrusion with drive rollers such as nip rollers and gear rollers, and feed it to the extrusion head while taking it up. This method is advantageous because it has a relatively simple structure and is suitable for producing small molded objects.

[0095] The material for the material extrusion method of this disclosure typically has a temperature of around 190 to 280°C to obtain suitable fluidity for extrusion, which is a temperature that can be set by a general-purpose 3D printer. In the manufacturing method of this disclosure, it is preferable to set the temperature inside the extrusion head to 280°C or less, preferably 220 to 270°C. Furthermore, for the substrate temperature, in the case of the FDM method, it is typically set to 95 to 105°C, usually around 100°C. In addition, if the table temperature and / or chamber temperature can be increased to around 150°C, for example, the bonding strength between the layered materials can be increased. On the other hand, in the case of the FGF method, depending on the nozzle diameter of the extrusion head, the substrate temperature is typically set to 65 to 85°C, usually around 80°C. Also, in the case of the FGF method, a substrate may not be used. By using these conditions, it is possible to stably manufacture molded objects.

[0096] The temperature of the material for the material extrusion method discharged from the extrusion head (discharge temperature) is preferably 180°C or higher, more preferably 190°C or higher, while preferably 270°C or lower, more preferably 260°C or lower, and even more preferably 240°C or lower. When the temperature of the material for the material extrusion method is above the above lower limit, it is preferable for extruding the material for the fused melt extrusion method of this disclosure, and is also preferable from the viewpoint of preventing stringing, which is the retention of thin, stretched fragments of the material for the material extrusion method in the molded product, thus degrading its appearance.

[0097] On the other hand, it is preferable that the temperature of the material for the material extrusion method is below the above upper limit, as this makes it easier to prevent defects such as foaming, thermal decomposition, burning, smoke, odor, and stickiness of the material for the material extrusion method of this disclosure, and also enables high-speed extrusion, which tends to improve molding efficiency.

[0098] In the case of FDM (Fiber Deposition Modeling), the material extruded from the extrusion head is preferably 0.1 to 1.0 mm in diameter, and more specifically, it is extruded as filaments with diameters of 0.2 to 1.0 mm, 0.2 to 0.8 mm, 0.2 to 0.6 mm, 0.2 to 0.4 mm, 0.4 to 1.0 mm, 0.4 to 0.8 mm, and 0.4 to 0.6 mm, forming monofilament threads. When formed from such monofilament threads, the resulting object is highly versatile. On the other hand, in the FGF method, the diameter of the nozzle tip of the extrusion head can be set to, for example, 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 8 mm, or 10 mm (the diameter of the monofilament thread is approximately 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 8.0, 10, 12, or 14 mm, and it may be within the range of any two of the values ​​exemplified here). This can be appropriately selected considering the balance between the quality of the printed object and the printing time.

[0099] When manufacturing objects using a 3D printer with fused deposition modeling (FGF) materials, the adhesion between layers of monofilament extruded monofilament material can be insufficient, and uneven extrusion can occur, resulting in uneven surfaces (steps) on the object's surface. This problem is particularly common when manufacturing large components using the FGF method. The presence of uneven surfaces on the object's surface can not only degrade its appearance but also lead to problems such as increased susceptibility to breakage.

[0100] The material for the material extrusion method for 3D printers disclosed herein has high melt fluidity during molding, so even when using the FGF method, uneven extrusion during molding is suppressed, and molded products with excellent appearance and surface properties can be stably manufactured.

[0101] When creating objects using a 3D printer by layering monofilament threads extruded from the extruder head, the material can sometimes adhere to the nozzle of the extruder head. Furthermore, this adhering material can become discolored by heat, resulting in black foreign matter (black spots or black streaks). When such foreign matter is mixed into the printed object, it can not only degrade its appearance but also cause problems such as making the object more prone to breakage.

[0102] The material for material extrusion for 3D printers disclosed herein is less likely to cause discoloration even when it adheres to the nozzle, thus enabling the stable production of molded objects with excellent appearance. [Examples]

[0103] The present disclosure will be described in more detail below with reference to examples, but the present disclosure is not limited to these examples.

[0104] [Production of polyhydric hydroxyl compounds] <Manufacturing Example 1> In a 2L stainless steel autoclave equipped with a stirrer and temperature control device, bisphenol A (900g), xylene (270g), and triethylamine (0.36g) were placed. After replacing the container with nitrogen gas, the mixture was heated until the temperature reached 80°C. Ethylene oxide (540g) was then added dropwise over 14 hours, maintaining the temperature at 75-80°C and the pressure at 0.15-0.25 MPa. The temperature was then raised to 110°C. At 15 hours from the start of the ethylene oxide addition, the pressure inside the container at 110°C stopped changing. The pressure inside the reaction vessel was then reduced while maintaining the temperature at 110°C, and the xylene was removed by distillation over 5 hours. Water (1.35g) and succinic acid (0.18g) were then added, and the mixture was stirred at 100°C for 2 hours to neutralize the triethylamine and obtain polyhydric hydroxyl compound (A-3).

[0105] <Manufacturing Example 2> Polyhydric hydroxyl compound (A-4) was obtained according to Production Example 1, except that the weight of ethylene oxide was changed from 540 g to 1400 g.

[0106] [Preparation of Cellulose Acetate Composition] <Examples 1-12, Comparative Example 1> To 100 parts by mass of cellulose acetate from Table 2, the other components shown in Table 2 were added and mixed by hand. At this time, the polyhydric hydroxyl compounds were used after temperature control at 60°C. Then, the mixture was thoroughly stirred at room temperature using a Henschel mixer (manufactured by Mitsui Miike Seisakusho Co., Ltd.). The resulting compound was extruded as strands using a 30 mmφ twin-screw extruder, and the air was cut off to form pellets (granulation process). The pellet size was approximately 3 mm in length and 2.5 mm in diameter. Finally, the pellets were dried in a dryer at 90°C for 3 hours.

[0107] <Volatile content at 230℃> A cellulose ester resin composition (X-1) was heated to 230°C using a thermogravimetric differential thermal analyzer (TG-DTA). The weight loss due to heating was measured, and the ratio of the weight loss to the weight before heating was calculated. The calculated value was recorded as the volatilization fraction at 230°C. Measurement device: Differential thermal balance (TG-DTA) (TG-8120, manufactured by Rigaku Corporation) Measurement conditions: In an air atmosphere, the material was heated from 40°C to 230°C at a heating rate of 10°C / min. The difference between the weight before heating and the weight at 230°C was calculated and defined as the weight loss.

[0108] The symbols listed in the raw material composition column of Table 2 represent the following raw materials, respectively. <Polyvalent hydroxyl compounds> (A-1): Nieuport BPE-40, n1+n2=4, X=dimethylmethylene group, hydroxyl group equivalent 275mgKOH / g, SP value 11.9 [Manufactured by Sanyo Chemical Industries, Ltd.] (A-2): Nieuport BPE-60, n1+n2=6, X=dimethylmethylene group, hydroxyl group equivalent 230mgKOH / g, SP value 11.4 [Manufactured by Sanyo Chemical Industries, Ltd.] (A-3): Produced in Production Example 1, n1+n2=3, X=dimethylmethylene group, hydroxyl group equivalent 320mgKOH / g, SP value 12.1 (A-4): Produced in Production Example 2, n1+n2=8, X=dimethylmethylene group, hydroxyl group equivalent 340 mgKOH / g, SP value 11.2

[0109] <Compound for comparison> Triethyl citrate, SP value 11.1, manufactured by Fujifilm Wako Pure Chemical Corporation.

[0110] <Cellulose ester> Cellulose acetate [Manufactured by Fujifilm Wako Pure Chemical Industries, degree of substitution: 2.4, average degree of polymerization: approximately 150, molecular weight: approximately 40,000]

[0111] [3D printing test] Using the cellulose ester resin compositions obtained in the examples and comparative examples as materials, objects were fabricated using a 3D printer (FGF type) with a screw-type extruder. The heating temperature at the extruder head (discharge temperature from the nozzle at the tip of the extruder head) was set to 220°C. The diameter of the nozzle at the tip of the extruder head was 10 mm, and the printing speed was 1000 mm / min, resulting in a basket-shaped object with a height of 200 mm.

[0112] [Evaluation of smoke emission suppression] In the aforementioned [3D printing test], the smoke emission from the nozzle tip was checked using the following method, and the smoke suppression of the cellulose ester resin composition was evaluated according to the following criteria. The results are shown in Table 2.

[0113] (Evaluation criteria for smoke emission suppression) Evaluation A: The cellulose ester resin composition was analyzed according to the method described above for <230°C volatility>, and its weight loss rate at 230°C was evaluated. A weight loss rate of less than 2% was considered OK, and a weight loss rate of 2% or more was considered NG. Evaluation B: Following the method described in [Evaluation of Smoke Emission Suppression], the emission of smoke during the printing process was visually checked. If no smoke was visually detected during printing, it was considered OK; if smoke was visually detected during printing, it was considered NG.

[0114] [Table 2]

[0115] <Filament Preparation (Examples 3, 6, 9)> Using a filament maker (Filament Maker Composer 450), 1.75 mm ± 0.1 mm filaments were produced from the pellets prepared in Examples 3, 6, and 9 under the conditions of a screw heating temperature of 245°C and a rotation speed of 3.5 rpm. These were then dried at 90°C for 3 hours.

[0116] <Filament fabrication (Comparative Example 1)> Using a filament maker (Filament Maker Composer 450), 1.75 mm ± 0.1 mm filaments were produced from each pellet prepared in Comparative Example 1 under the conditions of a screw heating temperature of 220°C and a rotation speed of 3.5 rpm. These were then dried at 80°C for 3 hours.

[0117] [3D Printer Modeling Test 2] Filaments prepared from the cellulose ester resin compositions obtained in Examples 3, 6, 9 and Comparative Example 1 were used as materials to fabricate objects using a filament-type 3D printer (FDM method). To suppress moisture absorption of the filament, a filament dryer was used during the fabrication process to dry the filament at 70°C. The heating temperature at the extruder head (extrusion temperature from the nozzle at the tip of the extruder head) was set to 250°C. The nozzle diameter at the tip of the extruder head was 0.4 mm, the printing speed was 60 mm / s, the table temperature was 150°C, and the chamber temperature was 150°C. A test piece measuring 20 mm x 20 mm and 1 mm thick was fabricated.

[0118] [Smoke suppression evaluation 2] In the aforementioned [Filament Preparation] and [3D Printing Test 2], the smoke emission from the tip nozzle was checked in the same manner as in the [3D Printing Test], and similar results were obtained.

Claims

1. A cellulose ester resin composition for use in a material extrusion method, comprising a cellulose ester resin and a polyhydric hydroxyl compound represented by the following general formula (1). 80(95) n1 --C 6 8 4 -8-3 6 8 4 --(EO) n2 -2 (1) [In general formula (1), C 6 H 4 [where n1 is a residue obtained by removing two hydrogen atoms from benzene, X is a methylene group or a dimethylmethylene group, E is an ethylene group, and n1 and n2 satisfy n1 + n2 = 3 to 8, and are independently integers from 1 to 7.]

2. The cellulose ester resin composition according to claim 1, wherein the cellulose ester resin is cellulose acetate.

3. The cellulose ester resin composition according to claim 1 or 2, wherein when the total mass of the cellulose ester resin and the polyhydric hydroxyl compound represented by general formula (1) is 100% by mass, the proportion of the mass of the polyhydric hydroxyl compound represented by general formula (1) is 10 to 50% by mass.

4. The cellulose ester resin composition according to claim 1 or 2, wherein when the total mass of the cellulose ester resin and the polyhydric hydroxyl compound represented by the general formula (1) is 100% by mass, the mass ratio of the cellulose ester resin is 50 to 90% by mass.

5. A cellulose ester resin composition according to claim 1 or 2, having a pellet-like or filament-like shape.

6. A 3D printing material comprising the cellulose ester resin composition according to claim 1 or 2.

7. A molded object formed from the 3D printing material described in claim 6.

8. A method for producing a molded object, comprising the step of molding a cellulose ester resin composition according to claim 1 or 2.

9. A method for manufacturing a 3D-printed object, The aforementioned 3D printer is Chamber and The chamber includes a heatable substrate, an extrusion head, and a supply unit for 3D printing material. It has at least the following features: The method for manufacturing a molded object according to claim 8, wherein the 3D printer material supply unit is supplied with the 3D printer material supply unit according to claim 6.

10. The extrusion head has a screw structure inside it, The method for manufacturing a molded object according to claim 9, wherein the extrusion head has a heating and melting function for the 3D printer material.

11. A method for producing a cellulose ester resin composition for use in a material extrusion method, comprising the step of melt-kneading a raw material composition containing a cellulose ester resin and a polyvalent hydroxyl compound represented by the following general formula (1). 80(95) n1 --C 6 8 4 -8-3 6 8 4 --(EO) n2 -2 (1) [In general formula (1), C 6 H 4 [where n1 is a residue obtained by removing two hydrogen atoms from benzene, X is a methylene group or a dimethylmethylene group, E is an ethylene group, and n1 and n2 satisfy n1 + n2 = 3 to 8, and are independently integers from 1 to 7.]

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