JPWO2016148280A1 - Fine cellulose fiber and use thereof - Google Patents

Abstract

The manufacturing method of the fine cellulose fiber characterized by including the process of amidating the carboxy group of the cellulose fiber which has a carboxy group, or a fine cellulose fiber using a non-volatile or a hardly volatile primary amine.

Description

  The present invention relates to fine cellulose fibers and uses thereof. In more detail, it is related with the manufacturing method of a fine cellulose fiber, the manufacturing method of a resin composition, a fine cellulose fiber, a resin composition, and a molded object. This application is based on provisional application 62 / 135,548 filed in the United States on March 19, 2015 and provisional application 62 / 247,208 filed in the United States on October 28, 2015. Claim the rights and incorporate their content here.

  Cellulose nanofibers (fine cellulose fibers) are skeletal components of plant cell walls, and are obtained by finely loosening plant fibers to nano size. Cellulose nanofibers are light, have high strength, have characteristics such as being able to be processed into a transparent material, and their application is expected.

  Initially, cellulose nanofibers were produced by mechanical shear loading that consumes significant energy. However, production methods using drugs or enzymes with lower energy consumption have been developed.

  Currently, most cellulose nanofibers are produced by a process including an oxidation treatment with 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO) or the like. When cellulose is oxidized by TEMPO, the hydroxyl group at the C6 position on the surface of the microfiber is converted to sodium carboxylate. Thus, cellulose nanofibers can be obtained by loosening individual microfibers by osmotic pressure, electrostatic repulsive force or the like under mild conditions with low energy consumption. Cellulose nanofibers produced by this technique are called TEMPO-oxidized cellulose nanofibrils (TOCNs).

  However, the application of a fine cellulose fiber having a carboxy group such as TOCNs is limited because of its low thermal decomposition temperature. The thermal decomposition temperature of cellulose is about 300 ° C., whereas the thermal decomposition temperature of fine cellulose fibers having a carboxy group is 200 to 220 ° C. (see, for example, Non-Patent Document 1).

Tang H., et al., A transparent, hazy, and strong macroscopic ribbon of oriented cellulose nanofibrils bearing poly (ethylene glycol)., Adv. Mater., 27 (12), 2070-2076, 2015.

  Then, this invention clarifies the cause of the low thermal decomposition temperature of the fine cellulose fiber which has a carboxy group, and it aims at providing the manufacturing method of the fine cellulose fiber with a high thermal decomposition temperature.

The present invention includes the following aspects.
(1) A method for producing a fine cellulose fiber, comprising a step of amidating a carboxy group of a cellulose fiber having a carboxy group or a fine cellulose fiber using a non-volatile or hardly volatile primary amine. .
(2) The method for producing fine cellulose fibers according to (1), wherein Tmax of the primary amine is 170 ° C. or higher.
(3) A step of mixing a cellulose fiber or fine cellulose fiber having a carboxy group with a non-volatile or hardly volatile primary amine to obtain a mixture, and a step of melt-kneading the mixture and the resin. The manufacturing method of the resin composition characterized by the above-mentioned.
(4) The method for producing a resin composition according to (3), wherein Tmax of the primary amine is 170 ° C. or higher.
(5) A fine cellulose fiber in which a part or all of the carboxy group is amidated, and the pyrolysis temperature is higher than that of the fine cellulose fiber having a carboxy group.
(6) The fine cellulose fiber according to (5), which has a thermal decomposition temperature of 250 ° C. or higher.
(7) The fine cellulose fiber according to (5) or (6), wherein the ratio of the amide group to the sum of the carboxy group and the amide group is 80 mol% or more.
(8) A resin composition containing the fine cellulose fiber according to any one of (5) to (7).
(9) A molded article comprising the resin composition according to (8).

  According to the present invention, a method for producing fine cellulose fibers having a high thermal decomposition temperature can be provided.

In Experimental Example 1, it is a graph showing representative results of Fourier transform infrared of the sample was modified TOCN in PEG-NH ₂ having a molecular weight of 1000 (FTIR) spectroscopy. In Experiment 2, it is a graph showing representative results of thermogravimetric analysis of the samples was modified TOCN in PEG-NH ₂ having a molecular weight of 1000. 10 is a graph showing the results of FTIR spectrum analysis in Experimental Example 3. It is a graph which shows the result of the thermal mass spectrometry in Experimental example 4. It is a graph which shows the result of the thermal mass spectrometry in Experimental example 4. It is a graph which shows the result of the thermal mass spectrometry of 3-amino-1-propanol (3AP) and 2- (2-aminoethoxy) ethanol (22AE) in Experimental example 5. In Experimental Example 5 is a graph showing the results of thermogravimetric analysis of PEG-NH ₂ (molecular weight 2000) and PNIPAm-NH ₂ (molecular weight 2500). It is a graph which shows the result of the thermal mass spectrometry in Experimental example 6. In the thermal mass spectrometry of Experimental example 6, it is a graph which shows the result of having calculated the value of -DTG. 14 is a graph showing the results of FTIR spectrum analysis in Experimental Example 7. It is a graph which shows the result of the thermal mass spectrometry in Experimental example 7. 10 is a graph showing the results of FTIR spectrum analysis in Experimental Example 8. It is a graph which shows the result of the thermal mass spectrometry of 2-aminofluorene in Experimental example 8.

[Production method of fine cellulose fiber]
In one embodiment, the present invention comprises a step of amidating a carboxy group of a cellulose fiber or a fine cellulose fiber having a carboxy group using a non-volatile or hardly volatile primary amine. A method for producing fine cellulose fibers is provided.

  As will be described later in Examples, the inventors have clarified that the reason for the low thermal decomposition temperature of fine cellulose fibers having a carboxy group is the presence of a carboxy group. The inventors have also clarified that fine cellulose fibers having a high thermal decomposition temperature can be produced by the production method of the present embodiment. Here, it can be said that the high thermal decomposition temperature means that the thermal stability is improved.

  As described later in Examples, the amidation of a carboxy group of a cellulose fiber or a fine cellulose fiber having a carboxy group is performed by, for example, mixing a cellulose fiber or a fine cellulose fiber and a primary amine, After forming an ionic bond between them, it can carry out by heating at about 150 degreeC under a normal pressure for 1 to 4 hours. Therefore, the primary amine is preferably a compound that can remain in the reaction system during the amidation reaction. More specifically, the primary amine is non-volatile or hardly volatile and may be any compound that does not volatilize or hardly volatilizes at about 150 ° C. under normal pressure.

  The Tamine of the primary amine is preferably 170 ° C. or higher. In the present specification, Tmax is a value obtained by adding a negative sign to a differential value of weight change (-DTG) when the target sample is subjected to thermogravimetric analysis, and expressed as a temperature on the horizontal axis. The temperature corresponding to the largest peak shall be said. Details will be described later.

  As will be described later in Examples, when a primary amine having a Tmax of 170 ° C. or higher is used, the carboxy group of the cellulose fiber or the fine cellulose fiber tends to be amidated. And the thermal decomposition temperature of a fine cellulose fiber can be improved by the amidation of the carboxy group of the cellulose fiber which has a carboxy group, or a fine cellulose fiber.

  Examples of the primary amine include a compound having a boiling point of 150 ° C. or higher, a polymer compound having an amino group, and the like. Further, the number of amino groups in one molecule of the primary amine is not particularly limited, and may be, for example, a monoamine, a diamine, or may have three or more amino groups. Examples of the polymer compound include polymers, and specific examples include those having an amino group among polyethylene glycol, polyoxyalkylene, polyacrylamide, copolymers thereof, and the like. More specific examples of the primary amine include compounds represented by the following formulas (1) to (4). These may be used individually by 1 type and may be used in combination of 2 or more type.

［式（１）中、ｍは任意の正数を表す。］

[In Formula (1), m represents arbitrary positive numbers. ]

［式（２）中、ｎは任意の正数を表す。］

[In Formula (2), n represents arbitrary positive numbers. ]

［式（３）中、ｐはそれぞれ独立に０〜４の整数を表し、ｑは０〜５の整数を表し、Ｒ^１はそれぞれ独立に、アミノ基、ハロゲン原子又は炭素数１〜３のアルキル基を表し、Ｒ^２は炭素数１〜３のアルキル基、−ＮＨ又は＝Ｏを表し、少なくとも１つのＲ^１はアミノ基である。ｐが２以上の整数である場合、複数存在するＲ^１はそれぞれ同一であってもよく、異なっていてもよい。］

[In Formula (3), p independently represents an integer of 0 to 4, q represents an integer of 0 to 5, and R ¹ each independently represents an amino group, a halogen atom, or an alkyl having 1 to 3 carbon atoms. R ² represents an alkyl group having 1 to 3 carbon atoms, —NH or ═O, and at least one R ¹ is an amino group. When p is an integer of 2 or more, a plurality of R ¹ may be the same or different. ]

［式（４）中、Ｒ^３は水素原子、アミノ基、炭素数１〜６の直鎖状若しくは分岐鎖状のアルキル基、−ＣＨ_２ＣＨ（ＣＨ_３）ＮＨ_２基、又は下記式（５）で表される基を表し、ａはエチレンオキシドの平均付加モル数を表す正数を表し、ｂはプロピレンオキシドの平均付加モル数を表す正数を表し、エチレンオキシド及びプロピレンオキシドはランダム状又はブロック状に存在する。］

[In the formula (4), R ³ represents a hydrogen atom, an amino group, a linear or branched alkyl group having 1 to 6 carbon atoms, a —CH ₂ CH (CH ₃ ) NH ₂ group, or the following formula (5 A represents a positive number representing the average number of moles of addition of ethylene oxide, b represents a positive number representing the average number of moles of addition of propylene oxide, and ethylene oxide and propylene oxide are in a random or block form Exists. ]

［式（５）中、Ｒ^４はフェニル基、水素原子、又は炭素数１〜３の直鎖若しくは分岐鎖のアルキル基を表し、ｃ及びｅはエチレンオキシドの平均付加モル数を表す０〜５０の整数を表し、ｄ及びｆはプロピレンオキシドの平均付加モル数を表す０〜５０の整数を表し、ｇは０又は１であり、＊は結合手を表し、エチレンオキシド及びプロピレンオキシドはランダム状又はブロック状に存在する。］

[In the formula (5), R ⁴ represents a phenyl group, a hydrogen atom, or a linear or branched alkyl group having 1 to 3 carbon atoms, and c and e represent an average number of added moles of ethylene oxide of 0 to 50. Represents an integer, d and f represent an integer of 0 to 50 representing the average number of added moles of propylene oxide, g is 0 or 1, * represents a bond, and ethylene oxide and propylene oxide are random or block Exists. ]

The compound represented by the above formula (1) is methoxypolyethylenepropylamine (PEG-NH ₂ ). The molecular weight of the compound represented by the above formula (1) may be, for example, about 1000 to 5000. The compound represented by the above formula (2) is terminal aminated poly (N-isopropylacrylamide). The molecular weight of the compound represented by the above formula (2) may be, for example, about 1000 to 5000.

  Specific examples of the compound represented by the above formula (3) include 2-aminofluorene described later in Examples. Since the compound represented by the formula (3) is a relatively low molecule, it tends to be easily mixed with cellulose fibers or fine cellulose fibers.

  Specific examples of the compound represented by the formula (4) include Jeffamine M-2070, Jeffamine M-2005, Jeffamine M-1000, Surfamine B200, Surfamine L100, Surfamine L200, Surfamine L200, Surfamine L200, Surfamine L200, Surfamine L200, Surfamine L200, Surfamine L200, and Surfamine L200. XTJ-501, XTJ-506, XTJ-507, XTJ-508; M3000 manufactured by BASF, Jeffamine ED-900, Jeffamine ED-2003, Jeffamine D-2000, Jeffamine D-4000, XTJ-510, Jeff-3 000 , Jeffamine T-5000, XTJ-502, XTJ-509, X J-510 and the like.

[Method for Producing Resin Composition]
In one embodiment, the present invention includes a step of mixing a cellulose fiber or fine cellulose fiber having a carboxy group and a non-volatile or hardly volatile primary amine to obtain a mixture, and melting the mixture and the resin. And a kneading step. A method for producing a resin composition is provided.

  Since the conventional fine cellulose fiber has a low thermal decomposition temperature, it may be decomposed at a melt-kneading temperature with a resin, and a resin composition having desired characteristics may not be obtained. In addition, gas such as carbon dioxide is generated in the process of decomposing fine cellulose fibers, which may hinder the production of the resin composition.

  On the other hand, according to the manufacturing method of the present embodiment, it is possible to manufacture a resin composition modified by advantageous characteristics of fine cellulose fibers. The manufacturing method of this embodiment will be described in more detail. First, a cellulose fiber or fine cellulose fiber having a carboxy group and a non-volatile or hardly volatile primary amine are mixed to obtain a mixture. In this process, the carboxy group contained in the cellulose fiber or fine cellulose fiber and the amino group of the primary amine form an ionic bond.

  Subsequently, in the step of melt-kneading the mixture and the resin, the carboxy group and the amino group are heated and reacted to form an amide bond. As a result, the thermal decomposition temperature of the fine cellulose fibers is increased, and the resin can be melted without being decomposed at the melt kneading temperature with the resin.

  According to the production method of the present embodiment, since the thermal decomposition temperature of the fine cellulose fibers can be simultaneously improved in the production process of the resin composition, the resin composition can be produced efficiently.

  The resin is not particularly limited. For example, polycarbonate resin; polyester resin such as polyethylene terephthalate resin, polytrimethylene terephthalate resin, polybutylene terephthalate resin; polystyrene resin, high impact polystyrene resin (HIPS), acrylonitrile-styrene copolymer Styrene (AS resin), acrylonitrile-butadiene-styrene copolymer (ABS resin), acrylonitrile-styrene-acrylic rubber copolymer (ASA resin), acrylonitrile-ethylenepropylene rubber-styrene copolymer (AES resin), etc. Polyolefin resin; Polyethylene resin; Polyimide resin; Polyether resin; Polyurethane resin; Polyphenylene ether resin; Sulfide resins; polysulfone resins; polymethacrylate resins. These resins may be used alone or in combination of two or more.

  In the manufacturing method of this embodiment, it is preferable that Tmax of a primary amine is 170 degreeC or more. Tmax is the same as described above. When the Tmax of the primary amine is 170 ° C. or higher, the thermal decomposition temperature of the fine cellulose fibers tends to be improved.

[Fine cellulose fiber]
In one embodiment, the present invention is a fine cellulose fiber in which part or all of the carboxy group is amidated, and the thermal decomposition temperature is higher than that of the fine cellulose fiber having a carboxy group. A fine cellulose fiber is provided.

  Since the fine cellulose fiber of this embodiment has improved thermal decomposition temperature, it can be easily applied to various applications. For example, the fine cellulose fiber of this embodiment may have a thermal decomposition temperature of 250 ° C. or higher, 280 ° C. or higher, or 290 ° C. or higher.

  In the fine cellulose fiber of the present embodiment, the ratio of the amide group to the total of the carboxy group and the amide group is preferably 80 mol% or more, preferably 90 mol% or more, and 95 mol% or more. It is particularly preferable that the amount is 100 mol%. The amount of carboxy group and amide group in the fine cellulose fiber can be measured by, for example, Fourier transform infrared (FTIR) spectrum analysis.

[Resin composition and molded body]
In one embodiment, the present invention provides a resin composition containing the fine cellulose fiber described above. The resin composition of the present embodiment is modified with fine cellulose fibers, and can exhibit excellent characteristics such as improvement in strength and weight reduction, for example.

  In one embodiment, the present invention provides a molded article comprising the above resin composition. Since the resin composition which is a material is modified with fine cellulose fibers, the molded body of this embodiment can exhibit excellent characteristics.

  EXAMPLES Next, although an Example is shown and this invention is demonstrated further in detail, this invention is not limited to a following example.

[Materials and methods]
(material)
Softwood bleached kraft pulp (manufactured by Nippon Paper Industries Co., Ltd.), which has never been dried, was used. The pulp contained about 90% cellulose and about 10% hemicellulose. 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO), sodium bromide, 1.77M sodium hypochlorite solution and sodium borohydride were purchased from Wako Pure Chemical Industries, Ltd. Methoxypolyethyleneglycolpropylamine (PEG-NH ₂ , chemical formula: CH ₃ O— (CH ₂ CH ₂ O) with polyethylene glycol (PEG 20H, 2000 g / mol), molecular weight 1000 (10H), 2000 (20H), 5000 (50H) _{) n -CH 2 CH 2 CH 2} NH 2) was purchased from NOF Corporation. Polyethylene glycol (PEG 200H, 2 × 10 ⁴ g / mol) was purchased from Wako Pure Chemical Industries, Ltd. Polyethylene oxide (PEO 10000H, 1 × 10 ⁶ g / mol) was purchased from Sigma-Aldrich.

(TOCNs)
TOCNs were prepared by the TEMPO / NaBr / NaClO system using 10 mmol NaClO / g cellulose. Oxidation with TEMPO was performed at pH 10 for 4 hours. After washing with deionized water, cellulose (TOC) oxidized by TEMPO was reduced with NaBH ₄ (0.1 g / g of pulp) in water at pH 10 to convert the remaining aldehydes and ketones to hydroxyl groups. . Thereafter, filtration and centrifugation were performed, and the product was sufficiently washed with deionized water.

  As a result of measuring the obtained TOC by conductivity titration, it contained 1.56 mmol / g carboxyl group. TOC was suspended in 100 mL of water at 0.1% w / w, and homogenized at room temperature and 10,000 rpm for 2 minutes using a double cylinder type homogenizer (model “Histcolon”, Microtech Nichion).

  Subsequently, the suspension was sonicated for 10 minutes at an output of about 70% using a 300 W ultrasonic homogenizer (model “US-300T”, probe tip diameter 26 mm, 19.5 kHz, Nippon Seiki Seisakusho Co., Ltd.). did.

  Subsequently, the mixture was centrifuged at 9000 rpm for 20 minutes, and the non-fibrotic fraction contained in the suspension was removed to obtain a TOCN suspension.

  Subsequently, 1M hydrochloric acid was added to the TOCN suspension and stirred for 30 minutes (pH 1 or less) to obtain TOCNs having a free carboxy group.

(Modification of TOCNs)
Coupling of PEG-NH ₂ to TOCNs was performed in an aqueous solvent at room temperature. The formation of an ionic bond between the carboxy group of TOCNs and the protonated amine group of PEG-NH ₂ results in a 0.1 wt% TOCN suspension and PEG-NH ₂ having a different carboxy group: amine molar ratio, ie Performed by mixing 1: 1, 1: 2, and 1: 4. The suspension was suspended at room temperature for 2 hours. No washing step was performed after the reaction.

(analysis)
The modified TOCN suspension was cast into a Petri dish and dried in an oven set at 40 ° C. for 3-4 days to produce a modified TOCN film.

Fourier transform infrared film (FTIR) spectra, transmission mode using a Fourier transform infrared spectrophotometer (Model "FT / IR-6100", JASCO Corporation), 400~4000cm ^-1, measured with a resolution ^{4 cm -1} did.

The thermogravimetric analysis (TGA) of the film was carried out using a differential thermal balance (model “TG8120”, Rigaku Corporation). At least 2 mg of film sample was set in a platinum pan. The PEG-NH ₂ powder was mixed with potassium bromide and finely crushed to prepare KBr pellets and measured.

  Thermal mass spectrometry was performed at 30 to 600 ° C. at a heating rate of 2, 5 or 10 ° C./min in a nitrogen atmosphere. The conversion of ionic bonds to amide bonds by heating was analyzed by TGA and FTIR spectra. The film sample was first heated at 150 ° C. for 2 or 4 hours with TGA under a nitrogen atmosphere. Subsequently, the film that was confirmed to be completely dried was mixed with potassium bromide and finely crushed to produce KBr pellets.

  Subsequently, using the obtained KBr pellet, FTIR spectrum analysis was performed under the above conditions. The reproducibility was confirmed by measuring at least 3 times per sample.

[Experimental Example 1]
PEG-NH ₂ having a molecular weight of 1000 (10H), 2000 (20H) and 5000 (50H) was mixed with a TOCN dispersion suspended in 0.1 wt% aqueous solvent. The molar ratio of carboxy group to amine was changed from 1: 1 to 1: 4. PH of the mixture was 7-9 depending on the amount of PEG-NH ₂ was added. The content of carboxy groups in cellulose oxidized by TEMPO (TOC) used for the preparation of TOCN was 1.56 mmol / g. After stirring for 2 hours, a transparent TOCN / PEG-NH ₂ film was produced by casting using each suspension.

FIG. 1 is a graph showing representative results of FTIR spectrum analysis of a sample in which TOCN is modified with PEG-NH ₂ having a molecular weight of 1000 as an example. In FIG. 1, TOCN indicates the result of TOCN not mixed with PEG-NH ₂ , and TOCN / PEG-NH ₂ (complete conversion) indicates the result of the sample in which the COOH group is completely converted to the COO ⁻ group. , TOCN / PEG-NH ₂ (incomplete conversion) shows the results of samples 20-25% to about COOH group is remained. As a result, as shown in FIG. 1, a peak of 1720 cm ⁻¹ COOH group (protonated carboxy group) was detected in addition to the cellulose peak in the FTIR spectrum of TOCN.

As a result of mixing with PEG-NH ₂ , the peak of the COOH group of TOCN shifted to 1600 cm ⁻¹ . Further, it was revealed that the peak at 1600 cm ⁻¹ corresponds to a COO ⁻ group (carboxy group).

Therefore, it became clear that almost all of the COOH groups of TOCN were converted to COO ⁻ groups having an ammonium salt structure. This is a result of ionic bonds are formed between the TOCN and PEG-NH _2.

From this result, it was confirmed that the coupling of PEG-NH ₂ to TOCN by the formation of an ionic bond was successful by the above method.

[Experiment 2]
Subsequently, the thermogravimetric analysis (TGA) of the TOCN / PEG-NH ₂ film sample of Experimental Example 1 was performed. FIG. 2 is a graph showing representative results of thermal mass spectrometry of a sample in which TOCN is modified with PEG-NH ₂ having a molecular weight of 1000 as an example. In Figure 2, TOCn shows the results of TOCn unmixed with _{PEG-NH 2, TOCN / PEG} -NH 2 ( complete conversion) is, COOH group is completely COO ^- shows the results of the samples converted based on , TOCN / PEG-NH ₂ (incomplete conversion) shows the results of samples 20-25% to about COOH group is remained. -DTG is a value obtained by adding a negative sign to the differential value of weight change. -Let Tmax be the temperature at the peak of DTG.

Table 1 shows the temperature at which the weight of the sample was reduced by _3% (T _3% ), the temperature at which the weight of the sample was reduced by _5% (T _5% ), and the weight of the sample by 10%. The temperature (T _10% ) and Tmax values are summarized.

As a result, as shown in FIG. 2 and Table 1, the coupling of PEG-NH ₂ to TOCN improved the thermal stability of TOCN. More specifically, the coupling of PEG-NH ₂ to TOCN increased Tmax by 80-90 ° C. compared to unmodified TOCN. In addition, the same tendency was observed when the experiment was conducted under any of the heating rates of 2, 5, and 10 ° C./min.

In addition, as a result of experiments by the inventors, the thermal decomposition temperature of the sample containing only PEG-NH ₂ (10H, 20H, and 50H) was 300 to 350 ° C.

[Experiment 3]
A primary amine was mixed with TOCN so that the molar ratio of COOH: NH ₂ was 1: 1, and a film of TOCN was prepared in the same manner as in Experimental Example 1 to examine the formation of ionic bonds. As the primary amine, 3-amino-1-propanol (3AP, the following formula (6)), 2- (2-aminoethoxy) ethanol (22AE, the following formula (7)), PEG-NH ₂ (molecular weight 2000) The following formula (8)) and PNIPAm-NH ₂ (molecular weight 2500, the following formula (9)) were used.

［式（１）中、ｍは分子量２０００となる正数を表す。］

[In the formula (1), m represents a positive number having a molecular weight of 2000. ]

［式（２）中、ｎは分子量２５００となる正数を表す。］

[In formula (2), n represents a positive number with a molecular weight of 2500. ]

Subsequently, each film was subjected to FTIR spectrum analysis in the same manner as in Experimental Example 1. FIG. 3 is a graph showing the results of FTIR spectrum analysis. In FIG. 3, TOCN is the result of the film of only TOCN, TOCN / 3AP is the result of the film prepared by mixing TOCN and 3-amino-1-propanol, and TOCN / 22AE is the result of TOCN and 2- (2 -Aminoethoxy) The result of the film prepared by mixing ethanol, TOCN / PEG-NH ₂ is the result of the film prepared by mixing TOCN and PEG-NH ₂ , and TOCN / PNIPAm-NH ₂ is the content of TOCN the result of that produced by mixing PNIPAm-NH ₂ film.

As a result, as shown in FIG. 3, it was confirmed that an ionic bond was formed between the carboxy group of TOCN and the amine when any primary amine other than PNIPAm-NH ₂ was used. . When PNIPAm-NH ₂ was used, the formation of ionic bonds could not be confirmed from the result of the FTIR spectrum due to the overlap of peaks.

[Experimental Example 4]
Each film of Experimental Example 3 was subjected to thermal mass spectrometry in the same manner as Experimental Example 2. FIG. 4 shows a TOCN-only film (TOCN), a film prepared by mixing TOCN and 3-amino-1-propanol (TOCN / 3AP), and a mixture of TOCN and 2- (2-aminoethoxy) ethanol. It is a graph which shows the result of the thermal mass spectrometry of the film (TOCN / 22AE) which was made. The heating rate was measured at 2 ° C./min. FIG. 5 shows a film made only of TOCN (TOCN), a film prepared by mixing TOCN and PEG-NH ₂ (TOCN / PEG-NH ₂ ), and a film prepared by mixing TOCN and PNIPAm-NH ₂ ( is a graph showing the results of thermogravimetric analysis of TOCN / PNIPAm-NH _2). The heating rate was measured at 2 ° C./min.

As a result, when 3-amino-1-propanol and 2- (2-aminoethoxy) ethanol were used as the primary amine, no improvement in the thermal stability of TOCN was observed. On the other hand, when PEG-NH ₂ or PNIPAm-NH ₂ was used as the primary amine, an improvement in thermal stability was recognized as compared with the film containing only TOCN.

[Experimental Example 5]
In the same manner as in Experimental Example 2, thermal mass spectrometry of 3-amino-1-propanol, 2- (2-aminoethoxy) ethanol, PEG-NH ₂ (molecular weight 2000) and PNIPAm-NH ₂ (molecular weight 75.11) was performed. And Tmax was measured. FIG. 6 is a graph showing the results of thermal mass spectrometry of 3-amino-1-propanol (3AP) and 2- (2-aminoethoxy) ethanol (22AE). The heating rate was measured at 2 ° C./min. FIG. 7 is a graph showing the results of thermal mass spectrometry of PEG-NH ₂ (molecular weight 2000) and PNIPAm-NH ₂ (molecular weight 2500). The heating rate was measured at 2 ° C./min.

As a result, it was revealed that the Tmax of 3-amino-1-propanol was about 100 ° C., and the Tmax of 2- (2-aminoethoxy) ethanol was about 160 ° C. Further, Tmax of PEG-NH ₂ (molecular weight 2000) and PNIPAm-NH ₂ (molecular weight 2500), it became clear both about 370 ° C..

[Experimental Example 6]
Polyethylene glycol having no amino group (PEG 200H, molecular weight 20000) and polyoxyethylene having no amino group (PEO 10000H, molecular weight 1000000) were mixed with TOCN so that the molar ratio was 1: 2, respectively. A TOCN film was prepared in the same manner as in Example 1.

  Subsequently, in the same manner as in Experimental Example 2, PEG 200H alone, PEO 10000H alone, and each of the produced films were subjected to thermal mass analysis. The heating rate was measured at 2 ° C./min.

  FIG. 8 is a graph showing the results of thermal mass spectrometry. FIG. 9 is a graph showing the result of calculating the value of -DTG. 8 and 9, PEG shows the result of PEG 200H only, PEO shows the result of PEO 10000H only, TOCN / PEG shows the result of the film prepared by mixing TOCN and PEG 200H, and TOCN / PEO Shows the result of a film prepared by mixing TOCN and PEO 10000H. As a result, no improvement in thermal stability was observed in any film. This result indicates that the presence of an amino group is necessary to improve the thermal stability of TOCN.

[Experimental Example 7]
TOCN was mixed with PNIPAm-NH ₂ (molecular weight 2500) so that the molar ratios of COOH: NH ₂ were 1: 0.25, 1: 0.5, and 1: 1. Films were prepared and ionic bond formation was studied.

FIG. 10 is a graph showing the results of FTIR spectrum analysis. As a result, COOH group peaks were observed in the samples having a COOH: NH ₂ molar ratio of 1: 0.25 and 1: 0.5. This result indicates that the ionic bond between the COOH group and the amine is insufficient and the COOH group remains.

Subsequently, thermal mass spectrometry was performed on each film in the same manner as in Experimental Example 2. FIG. 11 is a graph showing the results of thermal mass spectrometry. The heating rate was measured at 2 ° C./min. As a result, it became clear that as the molar ratio of NH _{2 to} COOH increases, the peak of -DTG present in the vicinity of 220 to 230 ° C. decreases. This result shows that it is important to completely ionize the COOH group with the amine in order to improve the thermal stability of TOCN.

[Experimental Example 8]
A TOCN film (TOCN / TOC) was prepared in the same manner as in Experimental Example 1 except that 2-aminofluorene (2AF) was mixed with TOCN, and a 1: 1 (mass ratio) mixture of water and isopropanol was used instead of the aqueous solvent. 2AF). A part of the produced film was heated at 150 ° C. for 4 hours in a nitrogen atmosphere. The chemical formula of 2-aminofluorene is shown in the following formula (10).

Subsequently, in the same manner as in Experimental Example 1, FTIR spectrum analysis was performed on the TOCN film, the TOCN / 2AF film (before heating), and the TOCN / 2AF film (after heating). FIG. 12 is a graph showing the results of FTIR spectrum analysis. As a result, as shown in FIG. 12, the TOCn / 2AF film (before heating), a portion of the peaks of the COOH groups of 1720 cm ^-1 is COO of 1600 cm ^{-1 -} revealed that shifted to the peak of the group . This shows that the carboxy group of TOCN and the amino group of 2-aminofluorene formed an ionic bond by mixing with 2-aminofluorene.

Furthermore, the TOCn / 2AF film (after heating), COO of 1600 cm ^{-1 -} peak groups revealed that shifted into two peaks of 1550 cm ^-1 and 1650 cm ^-1. Moreover, it was revealed that the peaks at 1550 cm ⁻¹ and 1650 cm ⁻¹ are both amide bond peaks. This result indicates that 2-aminofluorene can be used to improve the thermal stability of TOCN.

[Experimental Example 9]
In the same manner as in Experimental Example 2, thermal mass spectrometry of 2-aminofluorene (powder) was performed, and Tmax was measured. FIG. 13 is a graph showing the results of thermal mass spectrometry of 2-aminofluorene. The heating rate was measured at 2 ° C./min. As a result, it was revealed that Tmax of 2-aminofluorene was about 232 ° C.

  According to the present invention, a method for producing fine cellulose fibers having a high thermal decomposition temperature can be provided.

Claims (9)

  The manufacturing method of the fine cellulose fiber characterized by including the process of amidating the carboxy group of the cellulose fiber which has a carboxy group, or a fine cellulose fiber using a non-volatile or a hardly volatile primary amine.   The manufacturing method of the fine cellulose fiber of Claim 1 whose Tmax of the said primary amine is 170 degreeC or more. A step of mixing a cellulose fiber or fine cellulose fiber having a carboxy group and a non-volatile or hardly volatile primary amine to obtain a mixture;
Melting and kneading the mixture and resin;
The manufacturing method of the resin composition characterized by the above-mentioned.   The manufacturing method of the resin composition of Claim 3 whose Tmax of the said primary amine is 170 degreeC or more.   A fine cellulose fiber, wherein a part or all of the carboxy group is amidated, and the pyrolysis temperature is higher than that of the fine cellulose fiber having a carboxy group.   The fine cellulose fiber according to claim 5, wherein the pyrolysis temperature is 250 ° C or higher.   The fine cellulose fiber of Claim 5 or 6 whose ratio of the amide group with respect to the sum total of a carboxy group and an amide group is 80 mol% or more.   The resin composition containing the fine cellulose fiber as described in any one of Claims 5-7.   A molded body comprising the resin composition according to claim 8.

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