MATERIAL FOR HOT MELT EXTRUSION SYSTEM, MODELING MATERIAL FOR 3D PRINTERS, METHOD FOR PRODUCING MODELING MATERIAL FOR 3D PRINTERS, AND THREE-DIMENSIONAL MODEL

Abstract

A material for a hot melt extrusion method contains at least a cellulose derivative and an additive. The cellulose derivative is cellulose acetate propionate and when a degree of substitution of an acetyl group is X and a degree of substitution of a propionyl group is Y, the cellulose derivative satisfies the following Expression (1) and Expression (2); and the additive contains a plasticizer and a compound A containing a partial structure having a NICS value in the range of −14 or more and −10 or less,

[00001]$\begin{array}{cc}2.0\le X+Y\le 3.0& \mathrm{Expression}\left(1\right)\\ 0.5\le Y\le 2.6.& \mathrm{Expression}\left(2\right)\end{array}$

Claims

1. A material for a hot melt extrusion method containing at least a cellulose derivative and an additive, wherein the cellulose derivative is cellulose acetate propionate and when a degree of substitution of an acetyl group is X and a degree of substitution of a propionyl group is Y, the cellulose derivative satisfies the following Expression (1) and Expression (2); and the additive contains a plasticizer and a compound A containing a partial structure having a NICS value in the range of −14 or more and −10 or less, $\begin{array}{cc}2.0\le X+Y\le 3.0& \mathrm{Expression}\left(1\right)\\ 0.5\le Y\le 2.6.& \mathrm{Expression}\left(2\right)\end{array}$

2. The material for a hot melt extrusion method described in claim 1, wherein the compound A has a benzene ring and a 5-membered heterocycle in the structure.

3. The material for a hot melt extrusion method described in claim 1, wherein a content of the compound A is in the range of 0.1 to 30 mass %.

4. A modeling material for a 3D printer that is a monofilament yarn, wherein the monofilament yarn contain the material for a hot melt extrusion method described in claim 1.

5. A method for producing of a modeling material for a 3D printer, comprising the steps of: melt-extruding the material for a hot melt extrusion method described in claim 1; and then cooling and solidifying the melt-extruded material in the atmosphere or water to form monofilament yarn.

6. A three-dimensional shaped article containing the material for a hot melt extrusion method. described in claim 1, wherein the three-dimensional shaped article has an amount of dimensional change after leaving for 24 hours in an environment of 80° C. and 90% RH within ±5% of a dimensions before leaving the article.

Description

EXAMPLES

[0168] Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited thereto. In the examples, “parts” or “%” is used, but unless otherwise specified, it indicates “parts by mass” or “% by mass”.

Example 1

Molecular Weight Measurement of Cellulose Derivative

[0169] Since the average molecular weight and the molecular weight distribution of the cellulose derivative may be measured using high performance liquid chromatography, the weight average molecular weight (Mw) may be calculated using this.

[0170] The measurement conditions are as follows.

[0171] Solvent: Dichloromethane

[0172] Columns: Shodex K806, K805, K803 (three columns manufactured by Showa Denko K. K.) were connected and used.

[0173] Column temperature: 25° C.

[0174] Sample concentration: 0.1% by mass

[0175] Detector: RI Model 504 (manufactured by GL Sciences Inc.)

[0176] Pumps: L6000 (manufactured by Hitachi, Ltd.)

[0177] Flow rate: 1.0 mL/min

[0178] Calibration curves: Calibration curves with 13 samples of standard polystyrene STK standard polystyrene (manufactured by Tosoh Corporation) Mw=500-1000000 were used. 13 samples are used at approximately equal intervals.

Measurement of Substitution Degree of Cellulose Derivative

[0179] Based on ASTM D817-96, the substitution degree DS was determined as described below.

[0180] 1.90 g of the dried cellulose derivative was precisely weighed, and 70 mL of acetone and 30 mL of dimethyl sulfoxide were added and dissolved, followed by further addition of 50 mL of acetone. 30 mL of 1N sodium hydroxide aqueous solution was added while stirring, and the mixture was saponified for 2 hours. After adding 100 mL of hot water and washing the side of the flask, titration was performed with IN sulfuric acid with using phenolphthalein as indicator. Separately, a blank test was performed in the same manner as in the sample. The supernatant of the solution in which titration was completed was diluted 100 times, and the composition of the organic acid was measured by a conventional method using an ion chromatograph. From the measurement results and the acid composition analysis results by ion chromatograph, the degree of substitution was calculated by the following formula.

[00005]$\mathrm{TA}=\left(B-A\right)\times F\text{/}\left(1000\times W\right)$$X=\left(162.14\times \mathrm{TA}\right)\text{/}\left\{1-42.14\times \mathrm{TA}+\left(1-56.06\times \mathrm{TA}\right)\times \left(P\text{/}A\right)\right\}$$Y=X\times \left(P\text{/}A\right)$$\mathrm{DS}=X+Y$

[0181] A: Titration amount of sample (mL)

[0182] B: Titration amount of blank (mL)

[0183] F: Titer of 1N sulfuric acid

[0184] W: Sample mass (g)

[0185] TA: Total amount of organic acid (mol/g)

[0186] P/A: Molar ratio of acetic acid to propionic acid as determined by ion chromatography

[0187] X: Degree of substitution by acetic acid

[0188] Y: Degree of substitution by propionic acid

Fractionation of Cellulose

[0189] Cellulose having different molecular weights was separated with reference to the method described in Indian J. Chem. Tech., Vol. 3 (1996) p. 333.

[0190] 10 parts by mass of a-cellulose extracted from a Leucaena tree (Leucaena Leucocephala) and 12 parts by mass of paraformaldehyde are dissolved in 360 parts by mass of dimethyl sulfoxide (hereinafter, abbreviated as DMSO) by heating at 100° C. for 5 hours, and then 620 parts by weight of DMSO was added and cooled to 5° C.

[0191] While stirring this DMSO solution, 100 parts by mass of pure water was added, and the produced precipitate was filtered to obtain a solid obtained as cellulose “a”.

Synthesis of Cellulose Derivative

[0192] Various cellulose acetate propionates were synthesized with reference to Polymers for Advanced Technologies, vol. 14 (2003), p. 478.

Synthesis of Cellulose Derivative A1

[0193] To a solution obtained by mixing 100 parts by mass (100 parts by mole) of cellulose “a”, 420 parts by mass (1600 parts by mole) of lithium chloride, 11 parts by mass (30 parts by mole) of acetic acid, and 130 parts by mass (286 parts by mole) of propionic acid into 1000 parts by mass (10 times by volume) of dimethylacetamide, 405 parts by mass (320 parts by mole) of dicyclohexylcarbodiimide (DCC), 130 parts by mass (170 parts by mole) of dimethylaminopyridine, and 130 parts by mass (70 parts by mole) of dimethylaminopyridine-tosylate were added at room temperature. Then, the mixture was stirred for 24 hours until DCC was completely consumed. After completion of the reaction, the white precipitate produced by adding 5000 parts by mass of distilled water was filtered off. The filtered solid was washed several times with pure water, followed by Soxhlet extraction with methanol for 24 hours, and finally dried in vacuo at 70° C. to obtain a cellulose derivative A1. The degree of substitution and molecular weight of the obtained cellulose derivative were carried out according to the aforementioned measurement method, and the measurement results were described in Table II.

Synthesis of cellulose derivative A2

[0194] In synthesizing the cellulose derivative A1, synthesis was carried out in the same manner as in cellulose derivative A1, except that 11 parts by mass of acetic acid (30 parts by mol) was changed to 30 parts by mass (80 parts by mol), 130 parts by mass of propionic acid (286 parts by mol) was changed to 100 parts by mass (220 parts by mol), and 405 parts by mass (320 parts by mol) of DCC was changed to 380 parts by mass (300 parts by mol) to obtain a cellulose derivative A2.

Synthesis of Cellulose Derivative A3

[0195] Similarly, synthesis was carried out in the same manner as in cellulose derivative A1, except that 11 parts by mass (30 parts by mol) of acetic acid was changed to 70 parts by mass (110 parts by mol), 130 parts by mass (286 parts by mol) of propionic acid was changed to 50 parts by mass (110 parts by mol), and 405 parts by mass (320 parts by mol) of DCC was changed to 279 parts by mass (220 parts by mol) to obtain a cellulose derivative A3.

Synthesis of Cellulose Derivative A4

[0196] Similarly, synthesis was carried out in the same manner as in cellulose derivative A1, except that 11 parts by mass (30 parts by mol) of acetic acid was changed to 59 parts by mass (160 parts by mol), 130 parts by mass (286 parts by mol) of propionic acid was changed to 50 parts by mass (110 parts by mol), and 405 parts by mass (320 parts by mol) of DCC was changed to 342 parts by mass (270 parts by mol) to obtain a cellulose derivative A4.

Synthesis of Cellulose Derivative A5

[0197] Similarly, synthesis was carried out in the same manner as in cellulose derivative A1, except that 11 parts by mass of acetic acid (30 parts by mol) was changed to 78 parts by mass (210 parts by mol), 130 parts by mass (286 parts by mol) of propionic acid was changed to 41 parts by mass (90 parts by mol), and 405 parts by mass (320 parts by mol) of DCC was changed to 380 parts by mass (300 parts by mol) to obtain a cellulose derivative A5.

Synthesis of Cellulose Derivative A6

[0198] Similarly, synthesis was carried out in the same manner as in cellulose derivative A1, except that 11 parts by mass (30 parts by mol) of acetic acid was changed to 96 parts by mass (260 parts by mol), 130 parts by mass (286 parts by mol) of propionic acid was changed to 23 parts by mass (50 parts by mol), and 405 parts by mass (320 parts by mol) of DCC was changed to 380 parts by mass (300 parts by mol) to obtain a cellulose derivative A6.

Synthesis of Cellulose Derivative A7

[0199] Similarly, synthesis was carried out in the same manner as in cellulose derivative A1, except that 11 parts by mass of acetic acid (30 parts by mol) was removed and 130 parts by mass of propionic acid (286 parts by mol) was changed to 140 parts by mass (308 parts by mol) to obtain a cellulose derivative A7.

TABLE-US-00002 TABLE II Cellulose derivative Degree of substitution Weight average X Y molecular No. Raw material (Ac group) (Pr group) X + Y weight A1 Raw material “a” 0.2 2.6 2.8 331000 A2 Raw material “a” 0.6 2.0 2.6 341000 A3 Raw material “a” 1.0 1.0 2.0 307000 A4 Raw material “a” 1.4 1.0 2.4 319000 A5 Raw material “a” 2.1 0.5 2.6 322000 A6 Raw material “a” 2.3 0.3 2.6 325000 A7 Raw material “a” 0.0 2.8 2.8 327000

Plasticizer

[0200] The following plasticizer was used.

[0201] Trimethylolpropane tribenzoate (TMPBT): manufactured by ADEKA Corporation

##STR00014##

Additives

[0202] The following compounds were used as an additive (Compound A) having a benzene ring and a 5-membered heterocycle in the structure.

##STR00015##

[0203] Further, the following compounds were used as an additive in Comparative Examples.

##STR00016##

[0204] The NICS values in Table III was classified according to the following criteria based on the value of the ring having the largest NICS value among the aromatic rings in the above compound.

[0205] A: The value of the ring with the largest NICS value among the aromatic rings is −14 or more and −10 or less.

[0206] B: The value of the ring having the largest NICS value among the aromatic rings is less than 14, or more than −10.

TABLE-US-00003 TABLE III Type NICS value Remarks Additive 1 A Corresponds to Compound A Additive 2 A Corresponds to Compound A Additive 3 B Does not correspond to Compound A Additive 4 B Does not correspond to Compound A A: Among the aromatic rings, the value of the ring with the highest NISC value is -14 or more and −10 or less. B: Among the aromatic rings, the value of the ring with the highest N1SC value is less than −14 and exceeds -10.

Preparation of Monofilament Yarn Containing Material for Hot Melt Extrusion Method and Shaped Article

Preparation of Monofilament Yarn No. 1 Containing Material for Hot Melt Extrusion Method and Shaped Article No. 1

[0207] As a material for a hot melt extrusion method, a plasticizer was added to the cellulose derivative so that the amount of the plasticizer added was 5.0% by mass and the additive 1 was 3.0% by mass. A twin-screw kneading extruder (“BT-30” manufactured by Plastic Engineering Laboratory Co., Ltd., L/D=30) was used to combine the resin with the plasticizer and the additive to obtain a monofilament yarn. The monofilament yarn was pelletized with a length of 2 mm by a strand cutter, and injection molding was carried out using a small kneader manufactured by Xplore Corporation so as to have a length of 30 (vertical)×30 mm (horizontal) and a thickness of 100 μm to obtain a test piece of shaped article No. 1 for measuring the elastic modulus.

Preparation of Monofilament Yarns No. 2 to No. 23 Containing Material for Hot Melt Extrusion Method and Shaped Articles No. 2 to 23

[0208] Similarly, monofilament yarns No. 2 to No. 23 containing a material for a hot melt extrusion method were prepared by changing the amount of the plasticizer added, the type of the additive, and the amount of the additive so as to have the composition described in Table IV, and a test pieces of a shaped article No. 2 to No. 23 were obtained in the same manner.

Evaluation

(1) Elastic Modulus (Tensile Modulus of Elasticity)

[0209] For the materials for hot melt extrusion method, test pieces prepared with injection molded using a small kneader manufactured by Xplore Corporation under the above conditions and conditions in which additives 1 to 4 were not included were subjected to a tensile test using TENSILON universal tester (RTC-1250A type manufactured by Orientec Co., Ltd.), and their elastic moduli were compared.

[0210] Tensile test was carried out as follows. In accordance with the test method described in JIS K7127, using the test machine, the above test piece was subjected to a tensile test with the chuck-to-chuck distance of 50 mm in the MD direction (direction X) which is the injection direction of the test piece, and the tensile modulus of elasticity in the MD direction (direction X) was measured. Measurements were performed at 23° C. under 55% RH. The unit is GPa.

[0211] Elastic modulus ratio=Elastic modulus (conditions for preparing the material for a hot melt extrusion method)/Elastic modulus (conditions of removing the additive from the material for a hot melt extrusion method)

[0212] However, the material for the hot melt extrusion method No. 22 contains only a plasticizer, therefore the evaluation items related to elastic modulus are marked with “CC” in parentheses.

[0213] AA: A test piece containing a plasticizer and an additive has a tensile modulus ratio of 10% or more larger than that of a test piece containing only a plasticizer, and is particularly excellent in elastic modulus.

[0214] BB: A test piece containing a plasticizer and an additive has a high tensile modulus ratio in the range of 1% to less than 10% relative to a test piece containing only a plasticizer, and excellent in elastic modulus.

[0215] CC: A test piece containing a plasticizer and an additive has a tensile modulus ratio of equal to or lower than that of a test piece containing only a plasticizer, and is inferior in elastic modulus.

(2) Dimensional Stability at High Temperature and High Humidity

[0216] Using the monofilament yarns for a 3D printer described above, a rectangular parallelepiped of 30 (vertical)×30 (horizontal)×4 (thickness) (mm) was formed by an FDM printer (manufactured by Leapfrog Corporation, Creatr dual). The lengths of four randomly selected square portions of the rectangular parallelepiped before and after 24 hours under high temperature and high humidity conditions (80° C., 90% RH) were measured and used as the average dimension. Then, a value of the dimensional change rate calculated with (average dimension−30)/30 was obtained.

[0217] AA: 0 to ±3% or less, with particularly excellent dimensional stability

[0218] BB: ±3% or more, ±5% or less, with excellent dimensional stability

[0219] CC: Larger than ±5% and less dimensionally stable

[0220] The composition and evaluation results of the materials for a hot melt extrusion method described above are shown in Table IV.

TABLE-US-00004 TABLE IV Monofilament Additive yarn containing Plasticizer a material Added Added Evaluation for a hot melt amount amount Elastic extrusion method/ Cellulose [% by [% by modulus Dimensional shaped article No. derivative mass] Type mass] ratio stability Remarks 1 A1 5.0 Additive 1 3.0 BB BB Present invention 2 A1 5.0 Additive 1 5.0 BB AA Present invention 3 A1 5.0 Additive 1 10.0 AA AA Present invention 4 A1 5.0 Additive 2 5.0 BB BB Present invention 5 A1 5.0 Additive 2 10.0 M BB Present invention 6 A1 5.0 Additive 2 5.0 BB BB Present invention 7 A1 5.0 Additive 3 10.0 CC CC Comparative Example 8 A1 5.0 Additive 4 5.0 CC CC Comparative Example 9 A2 5.0 Additive 1 5.0 BB AA Present invention 10 A2 5.0 Additive 3 5.0 CC CC Comparative Example 11 A3 5.0 Additive 1 10.0 AA AA Present invention 12 A3 5.0 Additive 2 10.0 AA BB Present invention 13 A3 5.0 Additive 3 10.0 CC CC Comparative Example 14 A3 5.0 Additive 4 10.0 CC CC Comparative Example 15 A4 5.0 Additive 2 5.0 BB BB Present invention 16 A4 5.0 Additive 2 10.0 AA BB Present invention 17 A5 5.0 Additive 1 10.0 AA AA Present invention 18 A5 5.0 Additive 2 5.0 BB BB Present invention 19 A5 5.0 Additive 4 5.0 CC CC Comparative Example 20 A6 5.0 Additive 1 5.0 CC CC Comparative Example (Decomposition) 21 A7 5.0 Additive 2 5.0 CC CC Comparative Example 22 A1 20.0 — — (CC) (CC) Comparative Example 23 A1 — Additive 1 20.0 AA Cannot be Comparative Example modeled

[0221] From the results of Table IV, it is apparent that a material for a hot melt extrusion method containing a cellulose derivative, a plasticizer, and a compound A containing a partial structure of a specified range of NICS value as a constitution of the present invention is excellent in elastic modulus when processed into a shaped article and dimensional stability at high temperature and high humidity.

[0222] Especially in the structure, the level using the additive 1 having two rings of pyrazole ring was excellent in elastic modulus and dimensional stability.

INDUSTRIAL APPLICABILITY

[0223] Since the material for a hot melt extrusion method is excellent in elastic modulus and dimensional stability at high temperature and high humidity of a shaped article, the material for a hot melt extrusion method of the present invention is suitably used as a modeling material for a 3D printer.