Method for manufacturing a cellulose molded article and cellulose molded article

Abstract

To provide manufacturing method of a cellulose molding capable of obtaining a low-crystal cellulose molding by controlling molding conditions regardless of xylose concentration of a constituent sugar in a cellulose material, and the cellulose molding.SOLUTION: A method includes: a cellulose dissolving process of dissolving a cellulose material in a cellulose solvent to obtain a cellulose solution; a molding process of discharging the cellulose solution in an aqueous solution for molding, including 20-50% of the cellulose solvent, at 10-70°C to fabricate a wet molding; and a drying process of cleaning the wet molding, followed by drying, to obtain a cellulose molding.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for producing a cellulose molded body and a cellulose molded body.

Background Art

[0002] Generally, cellulose is produced by the viscose method in which a cellulose material such as pulp is immersed in an alkaline solution such as sodium hydroxide to form alkali cellulose, sulfated with carbon disulfide, and further viscose is produced by alkali dissolution, and the viscose is coagulated with an acid solution such as sulfuric acid. The cellulose thus produced is formed into an appropriate molded body such as fibrous, film-like, spherical, etc. depending on the shape at the time of coagulation, and is processed into various products such as paper products, clothing products, and sanitary products.

[0003] The viscose method has many steps from preparing viscose from a cellulose material, resulting in a huge amount of equipment and working hours. In addition, problems such as exhaust gas treatment and waste liquid treatment due to the use of alkaline solutions, acid solutions, hydrogen sulfide, etc., improvement of working efficiency and reduction of environmental load have become issues. Also, due to the working environment where sulfurous gas exists in processes such as the sulfation process, washing, and desulfurization, it was essential for workers to take safety measures such as wearing protective clothing.

[0004] Therefore, a method has been proposed for producing a cellulose film by directly dissolving a cellulose material without going through the step of producing viscose from the cellulose material (see, for example, Patent Document 1). In this production method, a cellulose material is dissolved in a mixed solvent containing an ionic liquid such as an imidazolium salt and an aprotic polar solvent to form a cellulose solution, and then the cellulose solution is coagulated to obtain a cellulose film. Therefore, the number of steps is reduced, the equipment burden is reduced, and the working efficiency is improved. At the same time, the working environment where sulfurous gas exists is eliminated, and safety measures are improved and the environmental load is reduced.

[0005] Furthermore, a manufacturing method has been proposed in which a mixed solvent of tetrabutylammonium acetate and an aprotic polar solvent such as dimethyl sulfoxide is used instead of an ionic liquid when directly dissolving cellulose material (see, for example, Patent Documents 2, 3, and 4). The mixed solvent used in this manufacturing method can improve productivity because tetrabutylammonium acetate has a higher dissolution efficiency and is cheaper compared to ionic liquids.

[0006] However, the above methods of directly dissolving cellulose materials to produce cellulose molded articles are all methods of producing cellulose films. Nevertheless, cellulose molded articles can be obtained in appropriate forms other than films, such as fibers or spheres. Of the molded articles obtained, films are mainly used for packaging, fibers are mainly used for cosmetics and textiles, and spheres (beads) are mainly used for cosmetic purposes, etc.

[0007] Generally, cellulose molded articles for cosmetic use require appropriate properties such as transparency and flexibility, those for textile use require dyeability, and those for packaging use require transparency. In these cellulose molded articles, the refractive index of light differs between the crystalline and amorphous parts of the cellulose. As the degree of crystallinity increases, light is scattered more diffusely, reducing transparency, while as the degree of crystallinity decreases, transparency and flexibility improve. Furthermore, the amorphous parts are more easily impregnated with dyes and chemicals, resulting in good dyeability and chemical reactivity during post-processing.

[0008] As a method for obtaining cellulose fibers with low crystallinity and good dyeability, a manufacturing method has been proposed that uses pulp containing a high concentration of hemicellulose, in which xylose or other sugars are constituent sugars, as the cellulose raw material (see, for example, Patent Document 5). However, in the above manufacturing method, it is necessary to adjust the xylose concentration in the constituent sugars of the raw material itself in order to obtain low-crystallinity cellulose fibers, making it difficult to arbitrarily adjust the degree of crystallinity.

[0009] Furthermore, because the cellulose fibers obtained by the above manufacturing method contain a high concentration of xylose as a constituent sugar, they may not meet the safety standards for sanitary materials when used in hygiene products such as nonwoven gauze. The medical nonwoven gauze standard, which conforms to the medical nonwoven fabric test methods of JIS L 1912 (1997), stipulates that, regarding distillation residue, one of the chemical requirements, the weight of the substance remaining after evaporating the solution obtained by boiling the nonwoven fabric in water must be 20.0 mg or less per 2 g of nonwoven fabric. In fibers that contain a high concentration of xylose as a constituent sugar, such as the cellulose fibers obtained by the above manufacturing method, xylose is easily eluted into hot water, which may cause the standard for distillation residue to be exceeded.

[0010] Therefore, the inventors diligently investigated a method for producing cellulose molded articles that allows control of the crystallinity of cellulose regardless of the xylose concentration in the constituent sugars of the raw materials. As a result, they invented a method that allows for the production of low-crystallinity cellulose molded articles regardless of the xylose concentration in the constituent sugars of the raw materials by adjusting the type, concentration, and temperature conditions of the solution used when solidifying the dissolved cellulose material. [Prior art documents] [Patent Documents]

[0011] [Patent Document 1] Japanese Patent Publication No. 2011-184541 [Patent Document 2] Japanese Patent Publication No. 2015-074704 [Patent Document 3] Japanese Patent Publication No. 2015-093876 [Patent Document 4] Japanese Patent Publication No. 2016-196526 [Patent Document 5] Special Publication No. 2021-517214 [Overview of the project] [Problems that the invention aims to solve]

[0012] The present invention has been made in view of the above points, and provides a method for producing a cellulose molded article and a cellulose molded article that can be obtained by adjusting the molding conditions, regardless of the xylose concentration in the constituent sugars of the cellulose material. [Means for solving the problem]

[0013] In other words, the first invention relates to a method for producing a cellulose molded article, comprising: a cellulose dissolution step of dissolving a cellulose material in a cellulose solvent to obtain a cellulose solution; a molding step of discharging the cellulose solution into a molding aqueous solution containing 20-50% of the cellulose solvent at 10-70°C to produce a wet molded article; and a drying step of washing and drying the wet molded article to obtain a cellulose molded article.

[0014] The second invention relates to a method for producing a cellulose molded article in which the cellulose material is pulp mainly composed of cellulose and contains 0.1 to 20% by weight of xylose as a constituent sugar, in the first invention.

[0015] The third invention relates to a method for producing a cellulose molded article in which, in the first or second invention, the cellulose solvent contains a tetraalkylammonium acetate represented by the following formula (Fi) and an aprotic polar solvent, and the content of the aprotic polar solvent is 55% by weight or more.

[0016] [ka] In the formula, R1, R2, R3, and R4 each independently represent an alkyl group having 3 to 6 carbon atoms.

[0017] The fourth invention relates to a method for producing a cellulose molded article in which, in the third invention, the hydrogen bond accepting ability (β value) of the Kamlet-Taft parameter of the cellulose solvent is 0.8 to 1.3.

[0018] The fifth invention relates to a method for producing a cellulose molded body, wherein in the third invention, the tetraalkylammonium acetate is tetrabutylammonium acetate.

[0019] The sixth invention relates to a method for producing a cellulose molded body, wherein in the third invention, the donor number of the aprotic polar solvent is 20 to 50.

[0020] The seventh invention relates to a method for producing a cellulose molded body, wherein in the third invention, the aprotic polar solvent is at least one selected from amide solvents, sulfoxide solvents, and pyridine solvents.

[0021] The eighth invention relates to a method for producing a cellulose molded body, wherein in the third invention, the aprotic polar solvent is at least one selected from the group consisting of N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, N,N-diethylacetamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone, N,N'-dimethylpropyleneurea, 1,3-dimethyl-2-imidazolidinone, tetramethylurea, tetraethylurea, pyridine, 4-methylpyridine, and derivatives thereof.

[0022] The ninth invention relates to a method for producing a cellulose molded body, wherein in the first invention, the cellulose molded body is in any form of fibrous, film-like, or spherical.

[0023] The tenth invention relates to a method for producing a cellulose molded body, wherein in the third invention, the cellulose molded body is in any form of fibrous, film-like, or spherical.

[0024] The eleventh invention relates to a method for producing a cellulose molded body, wherein in the eighth invention, the cellulose molded body is in any form of fibrous, film-like, or spherical.

[0025] The twelfth invention relates to a cellulose molded article obtained through a cellulose dissolution step of dissolving a cellulose material in a cellulose solvent to obtain a cellulose solution, a molding step of discharging the cellulose solution into a molding aqueous solution containing 20-50% of the cellulose solvent at 10-70°C to produce a wet molded article, and a drying step of washing and drying the wet molded article, wherein the degree of crystallinity of the cellulose molded article, represented by the following formula (i), is 60% or less.

[0026]

number

[0027] The 13th invention relates to a cellulose molded article in which the cellulose molded article contains 0.1 to 20% by weight of xylose as a constituent sugar, in accordance with the 12th invention.

[0028] The 14th invention relates to a cellulose molded article in which, in the 12th or 13th invention, the cellulose solvent contains a tetraalkylammonium acetate represented by the above formula (Fi) and an aprotic polar solvent, and the content of the aprotic polar solvent is 55% by weight or more.

[0029] The 15th invention relates to a cellulose molded article in which the hydrogen bond accepting ability (β value) of the Kamlet-Taft parameter of the cellulose solvent is 0.8 to 1.3, as described in the 14th invention.

[0030] The 16th invention relates to a cellulose molded article in which, in the 14th invention, the aprotic polar solvent is at least one selected from the group consisting of N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, N,N-diethylacetamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone, N,N'-dimethylpropyleneurea, 1,3-dimethyl-2-imidazolidinone, tetramethylurea, tetraethylurea, pyridine, and 4-methylpyridine, and derivatives thereof. [Effects of the Invention]

[0031] The method for producing a cellulose molded article according to the first invention includes a cellulose dissolution step of dissolving a cellulose material in a cellulose solvent to obtain a cellulose solution, a molding step of discharging the cellulose solution into a molding aqueous solution containing 20-50% of the cellulose solvent at 10-70°C to produce a wet molded article, and a drying step of washing and drying the wet molded article to obtain a cellulose molded article. Therefore, a low-crystallinity cellulose molded article can be provided by adjusting the molding conditions, regardless of the xylose concentration in the constituent sugars of the cellulose material.

[0032] According to the method for producing a cellulose molded article of the second invention, in the first invention, the cellulose material is pulp mainly composed of cellulose and contains 0.1 to 20% by weight of xylose as a constituent sugar. This makes it possible to use raw materials with high cellulose purity that were not conventionally used as raw materials for low-crystallinity cellulose molded articles, thus broadening the range of raw material choices and expanding the applications of the resulting molded article.

[0033] According to the method for producing a cellulose molded article of the third invention, in the first or second invention, the cellulose solvent contains tetraalkylammonium acetate and an aprotic polar solvent, and the content of the aprotic polar solvent is 55% by weight or more. Therefore, the cellulose material can be uniformly dissolved in a short time without a pretreatment step, regardless of the crystalline form of the cellulose material, and the fluidity of the cellulose solution obtained by dissolving the cellulose material can be increased.

[0034] According to the method for producing a cellulose molded article of the fourth invention, in the third invention, since the hydrogen bond accepting ability (β value) of the Kamlet-Taft parameter of the cellulose solvent is 0.8 to 1.3, the cellulose material can be uniformly dissolved in a short time without a pretreatment step, regardless of the crystalline form of the cellulose material, and the fluidity of the cellulose solution obtained by dissolving the cellulose material can be increased.

[0035] According to the method for producing a cellulose molded article of the fifth invention, in the third invention, since the tetraalkylammonium acetate is tetrabutylammonium acetate, the dissolution efficiency of the cellulose material is excellent.

[0036] According to the method for producing a cellulose molded article of the sixth invention, in the third invention, since the number of donors of the aprotic polar solvent is 20 to 50, the compatibility with tetraalkylammonium acetate is good, and the solubility of the cellulose material is good.

[0037] According to the method for producing a cellulose molded article of the seventh invention, in the third invention, the aprotic polar solvent is at least one selected from amide solvents, sulfoxide solvents, and pyridine solvents, thus providing good solubility for the cellulose material.

[0038] According to the method for producing a cellulose molded article of the eighth invention, in the third invention, the aprotic polar solvent is at least one selected from the group consisting of N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, N,N-diethylacetamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone, N,N'-dimethylpropylene urea, 1,3-dimethyl-2-imidazolidinone, tetramethylurea, tetraethylurea, pyridine, and 4-methylpyridine, and derivatives thereof. Therefore, it can be procured cheaply and easily, which is advantageous in terms of economy and mass production.

[0039] According to the method for manufacturing a cellulose molded article of the ninth invention, in the first invention, the cellulose molded article is in the form of fibers, film, or spheres, making it easy to manufacture the molded article and process the product.

[0040] According to the method for manufacturing a cellulose molded article of the 10th invention, in the third invention, the cellulose molded article is in the form of fibers, film, or spheres, making it easy to manufacture the molded article and process the product.

[0041] According to the method for manufacturing a cellulose molded article of the 11th invention, in the 7th invention, the cellulose molded article is in the form of fibers, film, or spheres, making it easy to manufacture the molded article and process the product.

[0042] The cellulose molded article according to the 12th invention comprises a cellulose dissolution step of dissolving a cellulose material in a cellulose solvent to obtain a cellulose solution, a molding step of producing a wet molded article by discharging the cellulose solution into a molding aqueous solution containing 20-50% of the cellulose solvent at 10-70°C, and a drying step of washing and drying the wet molded article. Since the crystallinity of the cellulose molded article is 60% or less, it has good performance in various aspects such as transparency, flexibility, dyeability, and chemical reactivity in post-processing when wet, and can be suitably used as a molding material for a wide variety of cellulose products depending on the form.

[0043] According to the cellulose molded article of the 13th invention, in the 12th invention, since the cellulose molded article contains 0.1 to 20% by weight of xylose as a constituent sugar, in addition to cellulose molded articles with low cellulose purity, it is also possible to provide cellulose molded articles with high cellulose purity that conform to various safety standards.

[0044] According to the cellulose molded article of the 14th invention, in the 12th or 13th invention, the cellulose solvent contains tetraalkylammonium acetate and an aprotic polar solvent, and the content of the aprotic polar solvent is 55% by weight or more. Therefore, the cellulose material can be uniformly dissolved in a short time without a pretreatment step, regardless of the crystalline form of the cellulose material, and the fluidity of the cellulose solution obtained by dissolving the cellulose material is increased, thereby improving the processability of the molded article.

[0045] According to the method for manufacturing a cellulose molded article of the 15th invention, in the 14th invention, since the hydrogen bond accepting ability (β value) of the Kamlet-Taft parameter of the cellulose solvent is 0.8 to 1.3, the cellulose material can be uniformly dissolved in a short time without a pretreatment step, regardless of the crystalline form of the cellulose material, and the fluidity of the cellulose solution obtained by dissolving the cellulose material can be increased, resulting in good processability of the molded article.

[0046] According to the cellulose molded article of the 16th invention, in the 14th invention, the aprotic polar solvent is at least one selected from the group consisting of N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, N,N-diethylacetamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone, N,N'-dimethylpropylene urea, 1,3-dimethyl-2-imidazolidinone, tetramethylurea, tetraethylurea, pyridine, and 4-methylpyridine, and derivatives thereof, and is therefore inexpensive and easily procured, which is advantageous in terms of economy and mass production. [Brief explanation of the drawing]

[0047] [Figure 1] This is a schematic process diagram of a method for manufacturing a cellulose molded article according to one embodiment of the present invention. [Modes for carrying out the invention]

[0048] The method for producing a cellulose molded article according to one embodiment of the present invention shown in Figure 1 is a method for obtaining a low-crystallinity cellulose molded article regardless of the xylose concentration in the constituent sugars of the cellulose material, and comprises a cellulose dissolution step, a molding step, and a drying step.

[0049] The cellulose molded articles obtained by the manufacturing method of the present invention can be molded into any suitable shape, but from the viewpoint of ease of manufacturing and product processing, it is preferable to mold them into a fibrous, film-like, or spherical shape. In particular, fibrous cellulose molded articles are so-called cellulose fibers and can be widely used as materials for processed products such as nonwoven fabrics. In the following description, unless otherwise specified, cellulose molded articles will be described as cellulose fibers (fibrous cellulose).

[0050] The cellulose dissolution process is a process of dissolving cellulose material in a cellulose solvent to obtain a cellulose solution. Cellulose material is a material containing cellulose components, and includes natural materials such as pulp and cotton, and processed materials such as paper products. Among natural materials, pulp is readily available and is preferably used as a cellulose material. In the case of processed materials, it is preferable from the viewpoint of reducing environmental impact to reuse discarded paper products and the like from the processed materials.

[0051] Pulp is a fibrous material obtained mainly by crushing wood and removing impurities. Generally, pulp used as a raw material for low-crystallinity cellulose molded articles is often pulp that has been obtained by removing impurities such as lignin and contains high concentrations of cellulose and xylose as a constituent sugar. In the method for producing cellulose molded articles of the present invention, pulp containing 0.1 to 20% by weight of xylose as a constituent sugar can be used as a raw material for low-crystallinity cellulose molded articles. In other words, in the production of low-crystallinity cellulose molded articles, it becomes possible to use pulp with high cellulose purity in addition to the pulp with low cellulose purity that is normally used. Therefore, not only is the range of raw materials that can be used broadened, but the range of applications for the resulting molded articles can also be expanded.

[0052] Furthermore, xylose, as a constituent sugar, inhibits the crystallization of cellulose when the cellulose solution solidifies, as described later. Therefore, it can also be added to arbitrarily control the crystallinity of cellulose. A cellulose molded body with a high degree of crystallinity has increased rigidity and decreased transparency, while one with a low degree of crystallinity is more flexible and has improved transparency. Therefore, the content may be adjusted as appropriate depending on the physical properties required for the desired cellulose molded body. In the following explanation, the cellulose material will be described as pulp.

[0053] A cellulose solvent is a solvent for dissolving cellulose materials such as pulp, and in particular, a solvent that can uniformly dissolve the pulp in a short time without pretreatment steps, regardless of the crystalline form of the pulp, is used. From the viewpoint of reducing environmental impact, it is preferable that the cellulose solvent does not contain halogens as anions. As the cellulose solvent, a solvent containing tetraalkylammonium acetate represented by the following formula (Fi) and an aprotic polar solvent is preferably used.

[0054] [ka]

[0055] In formula (Fi), R1, R2, R3, and R4 are alkyl groups having 3 to 6 carbon atoms. R1 to R4 may be the same alkyl group or different alkyl groups. If the alkyl group has 2 or fewer carbon atoms, or 7 or more carbon atoms, the solubility of the solvent in the pulp may decrease.

[0056] Kamlet-Taft parameters are used as evaluation indicators for the solvent properties of cellulose solvents. Kamlet-Taft parameters consist of three parameters: hydrogen bond acidity (α), hydrogen bond basicity (β), and bipolarity / polarity (π), with hydrogen bond basicity (β) being related to cellulose solubility. In the present invention, the desired cellulose solubility is preferably such that the hydrogen bond accepting ability (β value) of the Kamlet-Taft parameters is 0.8 to 1.3. By setting the hydrogen bond accepting ability (β value) of the Kamlet-Taft parameters of the cellulose solvent to 0.8 to 1.3, the cellulose material can be uniformly dissolved in a short time without pretreatment steps, regardless of the crystalline form of the cellulose material, and the fluidity of the cellulose solution obtained by dissolving the cellulose material can be increased.

[0057] Tetraalkylammonium acetate is a material used to efficiently dissolve cellulose materials such as pulp. This tetraalkylammonium acetate is used in combination of one or more of the following: tetrabutylammonium acetate, tetrapropylammonium acetate, tetrapentylammonium acetate, and tetrahexylammonium acetate.

[0058] Among the tetraalkylammonium acetates mentioned above, tetrabutylammonium acetate is preferred due to its excellent polysaccharide dissolution efficiency. Tetrabutylammonium acetate is an ionic ammonium acetate salt with a C4 alkyl group, possessing a good balance of affinity for hydrogen bonds and hydrophobicity as an organic substance. Due to these properties, it is thought that it penetrates between crystalline cellulose in pulp, breaking intermolecular and intramolecular hydrogen bonds, while re-aggregation is suppressed by the action of hydrophobic groups in the molecule. Therefore, it can efficiently dissolve the cellulose crystals, which are the main component of pulp.

[0059] Aprotic polar solvents are used to dissolve tetraalkylammonium acetates, such as tetrabutylammonium acetate, which are solids at room temperature. Furthermore, aprotic polar solvents enable homogeneous dissolution of tetraalkylammonium acetate in a short time, and can also lower the viscosity of the cellulose solution obtained by dissolving the pulp, thereby appropriately adjusting its fluidity.

[0060] Furthermore, since tetraalkylammonium acetate, which constitutes the cellulose solvent, has a strong electric charge, it readily forms electrostatic bonds with pulp, which has a large number of hydroxyl groups in its molecule, through hydrogen bonding and other means. Therefore, if a protic solvent is used, interactions (hydrogen bonding) with tetraalkylammonium acetate occur, inhibiting the cleavage of hydrogen bonds in cellulose by tetraalkylammonium acetate; for this reason, an aprotic catalyst is preferred. Moreover, since it is difficult to dissolve tetraalkylammonium acetate if a nonpolar solvent is used, a polar solvent is preferred. Accordingly, an aprotic polar solvent is preferably used as the solvent for cellulose.

[0061] The proportion of tetraalkylammonium acetate used is 1% to 45% by weight, preferably 5% to 40% by weight, and more preferably 10% to 35% by weight, from the viewpoint of solubility and dissolution rate in pulp. If the proportion of tetraalkylammonium acetate is too low, the pulp may not dissolve sufficiently, and if the proportion is too high, the solubility and dissolution rate of the pulp may decrease.

[0062] Aprotic polar solvents are preferably characterized by strong hydrogen bond acceptor properties and solubility parameters similar to those of tetraalkylammonium acetate. Therefore, aprotic polar solvents are preferably characterized by a donor number of 20 to 50, more preferably 25 to 40, and even more preferably 25 to 35. The donor number is one indicator of the basicity of a solvent, and is the value expressed as -ΔH (kcal / mol) of the heat of reaction (enthalpy) when solvent molecules react with 3 to 10 mol / L of Lewis acid (SbCl5) in a 1,2-dichloroethane solution. If the donor number is too small, the hydrogen bond acceptor properties of the aprotic polar solvent may decrease, potentially reducing the solubility of the pulp. If it is too large, the compatibility between the aprotic polar solvent and tetraalkylammonium acetate may decrease.

[0063] Furthermore, in the case of aprotic polar solvents, at least one selected from amide solvents, sulfoxide solvents, and pyridine solvents is preferably used from the viewpoint of solubility of tetraalkylammonium acetate and pulp. Specifically, at least one selected from the group consisting of N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, N,N-diethylacetamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone, N,N'-dimethylpropylene urea, 1,3-dimethyl-2-imidazolidinone (N,N'-dimethylethylene urea), tetramethylurea, tetraethylurea, pyridine, and 4-methylpyridine, and their derivatives. These are preferred from the viewpoint of economy and mass production because they are relatively inexpensive and easy to procure.

[0064] For the aprotic polar solvents listed above, the number of donors measured by the Gutmann method was 26.6 for N,N-dimethylformamide, 30.9 for N,N-diethylformamide, 27.8 for N,N-dimethylacetamide, 32.2 for N,N-diethylacetamide, 29.8 for dimethyl sulfoxide, 27.3 for N-methyl-2-pyrrolidone, 29.3 for N,N'-dimethylpropyleneurea, 27.8 for 1,3-dimethyl-2-imidazolidinone, 31.0 for tetramethylurea, 28.0 for tetraethylurea, 33.1 for pyridine, and 31.5 for 4-methylpyridine.

[0065] These aprotic polar solvents can be used individually or in combination of two or more. For example, when using two or more in combination, at least one of them should be an aprotic polar solvent with a donor number of 20 to 50, and the other aprotic polar solvents used in combination may be outside this range.

[0066] The content of the aprotic polar solvent is preferably 55% by weight or more, from the viewpoint of obtaining high fluidity in the cellulose solution obtained by dissolving pulp by reducing the content of tetraalkylammonium acetate in the cellulose solvent. Increased fluidity of the cellulose solution improves the processability of the molded article. The upper limit of the aprotic polar solvent content is not particularly limited as long as even a trace amount of tetraalkylammonium acetate is included, and it is not limited to 100% by weight. For example, the upper limit of the aprotic polar solvent content is 90-99% by weight. If the content of the aprotic polar solvent is too low, the cellulose solvent may become slurry-like, reducing fluidity and potentially worsening the fluidity and homogeneity of the cellulose solution obtained by dissolving pulp. Conversely, if the content is too high, the solubility of the pulp may decrease.

[0067] In cellulose solvents, the solubility and dissolution rate of pulp, as well as the viscosity of the cellulose solution, can be adjusted depending on the combination of tetraalkylammonium acetate and aprotic polar solvent used.

[0068] Here, we will explain the mechanism of dissolution of pulp (cellulose) by cellulose solvents. In cellulose solvents, tetraalkylammonium acetate is dissolved by an aprotic polar solvent (dimethyl sulfoxide in this example: DMSO) into the cation shown in formula (Fi) (tetraalkylammonium ion: TAA + ) and anions (acetate ion: CH3COO - ) is broken down into dimethyl sulfoxide (DMSO) oxygen and tetraalkylammonium ion (TAA + ) interacts with a macrocation ([DMSO+TAA] + ) is formed.

[0069] In cellulose solvent, pulp (cellulose) contains acetate ions (CH3COO - The hydrogen bonds in cellulose are broken by the acetate ion (CH3COO). - ) forms hydrogen bonds with it. Also, oxygen in cellulose and macrocations ([DMSO+TAA] + A weak interaction is formed between the two. As a result, cellulose is thought to exist in the solvent in the form shown in formula (Fii) below. Therefore, it is thought that it can be uniformly dissolved in a short time without pretreatment steps, regardless of the crystalline form of cellulose.

[0070] [ka]

[0071] The cellulose solution is a solution obtained by dissolving a predetermined amount of pulp in the cellulose solvent described above. The amount of pulp dissolved in the cellulose solvent is set according to the degree of polymerization, crystallinity, etc., but from the viewpoint of production efficiency, such as being able to easily prepare the cellulose solution with little burden and easy solidification, it is preferable that the amount added is at a concentration of about 3 to 15% by weight relative to the weight of the cellulose solvent. If the concentration of pulp is too dilute, the time required for solidification in the molding process described later will increase, and handling during processing and treatment may become difficult. If the concentration is too high, the viscosity of the cellulose solution will increase, requiring a long time to dissolve the pulp, and a large amount of tetraalkylammonium acetate will be required, which may be economically and efficiently disadvantageous.

[0072] When dissolving pulp in a cellulose solvent, it is preferable to use relatively mild temperature conditions for dissolution. The lower limit of the dissolution temperature is set to be above the solidification temperature of the aprotic polar solvent used, for example, around 20°C, from the viewpoint of ensuring the fluidity of the cellulose solvent and the reactivity between the pulp and tetraalkylammonium acetate. On the other hand, the upper limit of the dissolution temperature is set to, for example, around 50°C, from the viewpoint of controlling the reaction by suppressing excessive reaction between the pulp and tetraalkylammonium acetate and reducing the equipment required for heating. By dissolving pulp in a cellulose solvent at a mild temperature range, work can be carried out at room temperature, or if heating is required, a simple heating device is sufficient, thus eliminating the need for special heating equipment and reducing the equipment costs required for production. In addition, evaporation of components of the cellulose solvent can be suppressed, resulting in a safer working environment. It is possible to shorten the reaction time by raising the dissolution temperature, but it is not desirable to raise the dissolution temperature more than necessary due to reasons such as the decomposition of the cellulose solvent and the generation of colored substances due to side reactions.

[0073] Furthermore, when dissolving pulp in a cellulose solution, additives such as antioxidants, plasticizers, fillers, UV absorbers, pigments, antistatic agents, and other polymer materials may be added as needed. The amount of additives added should be appropriately determined depending on the type and application of the additive.

[0074] The cellulose solution is prepared by adding pulp, cellulose solvent, and additives as needed in a predetermined ratio, and stirring appropriately. For stirring the materials, mechanical stirring or ultrasonic vibration is suitable when the pulp content is relatively low and the cellulose solution has high fluidity, while a twin-screw extruder or kneader is suitable when the pulp content is relatively high and the cellulose solution has high viscosity. The stirring time depends on the fluidity of the solution, but is preferably about 10 to 90 minutes. If the stirring time is too short, it will be difficult to sufficiently dissolve the pulp. Also, if the stirring time is extended unnecessarily, no improvement in physical properties will be observed, so it should be stopped at an appropriate time. Stirring the materials promotes the dissolution of pulp and improves the uniformity of the solution. The pulp may also be dissolved in an inert gas. This suppresses the decrease in the degree of polymerization of cellulose in the pulp.

[0075] The molding process involves molding the cellulose solution obtained in the cellulose dissolution process into a wet molded body (fibrous wet molded body). This process involves extruding the cellulose solution into a molding aqueous solution at 10-70°C to produce the wet molded body. The wet molded body (fibrous wet molded body) is an intermediate product of the final cellulose molded body (cellulose fiber).

[0076] For dispensing the cellulose solution, a known dispensing device corresponding to the desired shape of the molded body is used as appropriate. For example, when molding cellulose fibers, spunbond dies or melt-blown dies are used. When molding cellulose films, T-dies or inflation dies are used. Furthermore, when molding cellulose beads, atomizers or spray dryers are used.

[0077] The molding aqueous solution is an aqueous solution containing 20-50% of the same cellulose solvent used in the cellulose dissolution process, and solidifies upon contact with the cellulose solution. The materials constituting the molding aqueous solution are cellulose solvent and ion-exchanged water. If the cellulose solvent content is too low, the solidification rate of the discharged cellulose solution will be too fast, and cellulose crystallization will proceed easily, potentially leading to an excessive degree of crystallization. Conversely, if the content is too high, the solidification of the cellulose solution will be insufficient, potentially making molding difficult.

[0078] The reaction conditions between the cellulose solution and the molding aqueous solution are such that the temperature is approximately 10 to 70°C, preferably 10 to 40°C. If the temperature of the molding aqueous solution is too high, it will solidify rapidly, which may reduce the density and strength of the cellulose molded product. In addition, the energy cost required to maintain the temperature of the molding aqueous solution will be high.

[0079] When a cellulose solution is discharged into a molding aqueous solution, the cellulose solution is coagulated by the molding aqueous solution, yielding a transparent wet molded body (fibrous wet molded body) consisting of cellulose components and residual cellulose solvent. Meanwhile, the cellulose solvent components (tetraalkylammonium acetate, aprotic polar solvent) separated from the cellulose and eluted into the molding aqueous solution are recovered by fractional distillation or other methods. After recovery, they are subjected to treatments such as filtration and purification, making them reusable as cellulose solvent.

[0080] The drying process involves washing the wet molded body (fibrous wet molded body) obtained in the molding process, and then drying it to obtain a cellulose molded body (fibrous cellulose). The washing of the wet molded body is performed by contacting the wet molded body with a washing solution such as water in a room temperature environment of about 20-30°C, thereby replacing and separating the cellulose solvent in the wet molded body with the washing water. As the washing water, a solvent with high affinity for cellulose and no solubility is preferred, and readily available water is particularly preferred. This washing is preferably performed multiple times (about twice) from the viewpoint of more reliably removing components other than cellulose from the wet molded body.

[0081] A cellulose molded body (fibrous cellulose) can be obtained by appropriately drying the wet molded body after washing. The drying method is not particularly limited as long as the wet molded body after washing can be dried, and can be any method such as natural drying at room temperature, drying by heating rolls or hot air, etc. Since no exhaust gas is generated in this drying process, exhaust gas treatment such as sulfur gas, which is performed in the viscose process, is unnecessary.

[0082] In the method for manufacturing cellulose molded articles of the present invention, the cellulose solvent used to directly dissolve the cellulose material is separated from the cellulose component in the molding process as described above. Therefore, it can be separated into water and cellulose solvent and recovered by fractional distillation of the molding aqueous solution during the processing process, and the recovered cellulose solvent can be reused to dissolve the cellulose material. For this reason, when manufacturing cellulose molded articles continuously, the amount of cellulose solvent used only needs to be replenished to compensate for the unavoidable consumption, thus reducing the amount used and making it economical while also reducing the environmental impact.

[0083] In the present invention's method for producing cellulose molded articles, a cellulose solution containing dissolved cellulose material can be easily molded into a low-crystalline cellulose molded article by contacting it with a molding aqueous solution whose cellulose solvent concentration and aqueous solution temperature have been adjusted. Therefore, in the molding process, a cellulose molded article of any desired shape can be obtained by dispensing the cellulose solution into the molding aqueous solution using a dispensing method corresponding to the desired shape, such as fibrous, film-like, or spherical.

[0084] The low-crystallinity cellulose molded articles of the present invention exhibit good performance in various aspects, including transparency, flexibility, dyeability, and chemical reactivity in post-processing when wet. The crystallinity of these cellulose molded articles is preferably 60% or less. Crystallinity indicates the proportion of crystalline components in the cellulose molded article and affects physical properties such as transparency and strength. Since the morphology of crystals within the molded article is not constant, there may be some variation in the transparency of the cellulose molded article depending on the crystal morphology; however, generally, the lower the crystallinity, the better the transparency of the cellulose molded article tends to be.

[0085] The cellulose molded article obtained by the manufacturing method of the present invention has a cellulose type II crystal structure. Generally, natural cellulose materials such as pulp have a cellulose type I crystal structure. On the other hand, when natural cellulose materials are mercerized or regenerated by dissolving them in a cellulose solvent, the crystal structure changes to cellulose type II. Therefore, the degree of crystallinity can be calculated by X-ray diffraction measurement using the following formula (i). In formula (i), Ic is the diffraction intensity of the cellulose type II crystal lattice plane ((1-10) plane, peak value around 2θ=13°), Ia1 is the diffraction intensity at the point where the line connecting the diffraction intensities at 2θ=8° and 15° intersects with the line drawn perpendicularly from 13°, and Ia2 is the diffraction intensity of the amorphous portion (2θ=15°).

[0086]

number

[0087] The cellulose molded articles of the present invention, having a crystallinity of 60% or less, exhibit improved performance in various aspects such as transparency when wet, flexibility, dyeability, and chemical reactivity during post-processing. The transparency of the cellulose molded articles contributes to their appearance. Highly transparent cellulose molded articles have good design and aesthetic appeal, and clean-looking products can be obtained through processing. Thus, the cellulose molded articles of the present invention are molded as high-quality materials with excellent transparency in any shape. Therefore, they can be suitably used as molding materials for a wide variety of cellulose products depending on the shape of the cellulose molded article.

[0088] Furthermore, in the low-crystalline cellulose molded articles of the present invention, xylose is contained in a constituent sugar of 0.1 to 20% by weight, corresponding to the xylose concentration in the constituent sugars of the cellulose material used. This includes not only low-crystalline cellulose molded articles obtained from raw materials with low cellulose purity, but also low-crystalline cellulose molded articles obtained from raw materials with high cellulose purity. Cellulose molded articles made from high-purity cellulose contain only a small amount of xylose as a constituent sugar, and therefore can be produced as products that meet safety standards such as distillation residue standards.

[0089] Thus, the cellulose molded articles of the present invention have excellent appearance, including design and aesthetic appeal, due to their superior transparency resulting from their low crystallinity, and also offer superior safety because they are molded from high-purity cellulose. Therefore, products with a clean appearance can be obtained through processing, making them useful as molding materials for a wide range of products, such as cosmetics like face masks and medical supplies like medical masks. [Examples]

[0090] [Preparation of Cellulose Molded Products] In preparing the cellulose molded bodies for prototype examples 1 to 11, 1410 g of the cellulose solvent described later was placed in a 2 L separable flask, and 90 g of the cellulose material described later was added to the cellulose solvent. The mixture was then dissolved in a 55°C water bath while stirring with a stirrer (manufactured by Shinko Environmental Solutions Co., Ltd.; "Logbone") to obtain a cellulose solution.

[0091] Next, using a cellulose solvent prepared identically to the one used to dissolve the cellulose material, molding aqueous solutions were prepared with different mixing ratios and aqueous solution temperatures. The cellulose solution was then discharged from a nozzle into the molding aqueous solution using a gear pump (Barmag; "Oerlikon") to solidify and obtain a fibrous wet molded body. After washing the obtained wet molded body with running water, it was air-dried to obtain the fibrous cellulose molded bodies of prototypes 1 to 11.

[0092] [Cellulose solvent] A cellulose solvent was obtained by mixing 28% by weight of tetrabutylammonium acetate (manufactured by Tokyo Chemical Industry Co., Ltd.) as the tetraalkylammonium acetate and 72% by weight of dimethyl sulfoxide (manufactured by Kishida Chemical Co., Ltd.) as the aprotic polar solvent.

[0093] The hydrogen bond acceptance capacity (β value) of the Kamlet-Taft parameter of the obtained cellulose solvent was 1.1. The hydrogen bond acceptance capacity (β value) of the Kamlet-Taft parameter was measured based on "Lauri KJHauru et al., Biomacromolecules 2012,13,2896-2905".

[0094] [Cellulose material] • Pulp 1: Dissolved pulp (manufactured by Oji Paper Co., Ltd.; "LDKP"), xylose concentration in constituent sugars: 1.9% • Pulp 2: Dissolved pulp (manufactured by Nippon Paper Industries Co., Ltd.; "LBKP"), xylose concentration in constituent sugars: 17.1% • Pulp 3: Cotton linter pulp (manufactured by Buckeye), xylose concentration in constituent sugars 0.3%

[0095] [Prototype Example 1] Prototype Example 1 is a fibrous cellulose molded body obtained by coagulating a cellulose solution of pulp 1 (xylose concentration in constituent sugars of 1.9%) with a molding aqueous solution with a concentration of 20% and an aqueous solution temperature of 10°C.

[0096] [Prototype Example 2] Prototype Example 2 is a fibrous cellulose molded body obtained by coagulating a cellulose solution of pulp 2 (xylose concentration in constituent sugars 17.1%) with a molding aqueous solution at a concentration of 20% and an aqueous solution temperature of 20°C.

[0097] [Prototype Example 3] Prototype Example 3 is a fibrous cellulose molded body obtained by coagulating a cellulose solution of pulp 1 (xylose concentration in constituent sugars of 1.9%) with a molding aqueous solution at a concentration of 20% and an aqueous solution temperature of 70°C.

[0098] [Prototype Example 4] Prototype example 4 is a fibrous cellulose molded body obtained by coagulating a cellulose solution of pulp 3 (xylose concentration in constituent sugars of 0.3%) with a molding aqueous solution with a concentration of 20% and an aqueous solution temperature of 70°C.

[0099] [Prototype Example 5] Prototype Example 5 is a fibrous cellulose molded body obtained by coagulating a cellulose solution of pulp 2 (xylose concentration in constituent sugars of 17.1%) with a molding aqueous solution at a concentration of 50% and an aqueous solution temperature of 20°C.

[0100] [Prototype Example 6] Prototype example 6 is a fibrous cellulose molded body obtained by coagulating a cellulose solution of pulp 1 (xylose concentration in constituent sugars of 1.9%) with a molding aqueous solution at a concentration of 50% and an aqueous solution temperature of 70°C.

[0101] [Prototype Example 7] Prototype Example 7 is a fibrous cellulose molded body obtained by coagulating a cellulose solution of pulp 1 (xylose concentration in constituent sugars of 1.9%) with a molding aqueous solution at a concentration of 10% and an aqueous solution temperature of 10°C.

[0102] [Prototype Example 8] Prototype Example 8 is a fibrous cellulose molded body obtained by coagulating a cellulose solution of pulp 1 (xylose concentration in constituent sugars of 1.9%) with a molding aqueous solution at a concentration of 20% and an aqueous solution temperature of 5°C.

[0103] [Prototype Example 9] Prototype Example 9 is a fibrous cellulose molded body obtained by solidifying a cellulose solution of pulp 1 (xylose concentration in constituent sugars of 1.9%) with a molding aqueous solution of 0% concentration (no cellulose solvent) and an aqueous solution temperature of 5°C.

[0104] [Prototype Example 10] Prototype example 10 is a fibrous cellulose molded body obtained by coagulating a cellulose solution of pulp 1 (xylose concentration in constituent sugars of 1.9%) with a molding aqueous solution of 0% concentration (no cellulose solvent) and an aqueous solution temperature of 10°C.

[0105] [Prototype Example 11] Prototype example 11 is a fibrous cellulose molded body obtained by coagulating a cellulose solution of pulp 1 (xylose concentration in constituent sugars of 1.9%) with a molding aqueous solution of 0% concentration (no cellulose solvent) and an aqueous solution temperature of 20°C.

[0106] For the fibrous cellulose molded articles of prototypes 1 to 11, tests were conducted on the xylose concentration in the constituent sugars, the degree of crystallinity, and the transparency when wet to determine their quality. The test results for the xylose concentration in the constituent sugars, the degree of crystallinity, and the transparency of the molded articles, along with the xylose concentration in the constituent sugars of the cellulose material, the concentration of the cellulose solvent in the molding aqueous solution, and the aqueous solution temperature, are shown in Table 1 below.

[0107] [Measurement of xylose concentration in constituent sugars] The fibrous cellulose molded bodies of prototypes 1 to 11 were dissolved in 72% by weight sulfuric acid in a 30°C water bath. Water was added to dilute the sulfuric acid to 4.5% by weight, and the mixture was treated in a 120°C oil bath for 15 minutes to hydrolyze the sugar components in the cellulose molded bodies to monosaccharides. The xylose concentration (%) in the hydrolyzed solution was measured using a high-performance liquid chromatograph (HPLC) (Shimadzu Corporation; "Prominence"). A ligand exchange chromatography column (Shoko Science Co., Ltd.; "SUGAR SP0810") was used for sugar separation.

[0108] [Measurement of crystallinity] The degree of crystallinity (%) of cellulose was calculated using equation (i) above by wide-angle X-ray diffraction (WAXD) measurement with a fully automated multi-purpose X-ray diffractometer (manufactured by Rigaku Corporation; "SmartLab"). The conditions were a measurement angle 2θ = 5 to 40°, a voltage of 40kV, and a current of 30mA.

[0109] [Test of transparency when wet] For the fibrous cellulose molded bodies of prototypes 1 to 11, fibers cut to a length of 50 mm were dispersed in water to form a slurry, and short-fiber cylindrical sheet test specimens were prepared by suction filtration. The basis weight for each test specimen was 55 g / m². 2 The test specimen was adjusted to achieve the following. Deionized water was dropped onto the resulting short-fiber cylindrical sheet-shaped test specimen to uniformly moisten the entire surface. The moistened test specimen was then placed on a sheet printed with black characters, and the visibility (transparency) of the characters was visually determined. In determining transparency, a "○ (acceptable)" rating was used if the characters were highly visible (the characters were clearly visible), and a "× (unacceptable)" rating was used if the characters were not clearly visible (the characters were not clearly visible).

[0110] [Table 1]

[0111] [Results and Discussion] When comparing prototypes 1, 3, and 8 (material: pulp 1, concentration: 20%), where the cellulose material and the cellulose solvent concentration of the molding aqueous solution were the same, a tendency was observed for the degree of crystallinity of the cellulose molded body to decrease as the temperature of the molding aqueous solution increased. This is thought to be because when a cellulose solution is solidified in a high-temperature aqueous solution containing cellulose solvent, the rate at which solid material precipitates from the cellulose solution is rapid, and the cellulose precipitates before it can form a crystal lattice, increasing the amount of amorphous material and decreasing the degree of crystallinity. In addition, in prototype example 8, where the temperature of the molding aqueous solution was 5°C, the visibility of the letters on which the test specimen was placed was low, and the transparency was insufficient.

[0112] When comparing prototypes 1, 7, and 10 (material: pulp 1, temperature: 10°C), prototypes 2 and 5 (material: pulp 2, temperature: 20°C), prototypes 3 and 6 (material: pulp 1, temperature: 70°C), and prototypes 8 and 9 (material: pulp 1, temperature: 5°C), where the cellulose material and the temperature of the molding aqueous solution were the same, a tendency was shown for the degree of crystallization to decrease as the concentration of cellulose solvent in the molding aqueous solution increased. This is thought to be because when a cellulose solution is solidified in an aqueous solution containing a high concentration of cellulose solvent, the rate at which the cellulose solvent escapes from the cellulose solution is slow, and the cellulose solvent inhibits the crystallization of cellulose, resulting in a decrease in the degree of crystallization. Furthermore, in prototypes 9, 10, and 11, where the molding aqueous solution did not contain cellulose solvent, the visibility of the letters on which the test specimens were placed was low and the transparency was insufficient, regardless of the temperature of the molding aqueous solution. Even in prototype 7, where the concentration of cellulose solvent was 10%, the transparency was insufficient.

[0113] When comparing prototypes 3 and 4 (concentration: 20%, temperature: 70°C), where the cellulose solvent concentration and temperature of the molding aqueous solution were the same, a tendency was observed for the degree of crystallinity to decrease as the xylose concentration in the constituent sugars of the cellulose material increased. This is thought to be because the xylose contained as a constituent sugar inhibits the crystallization of cellulose when the cellulose solution solidifies, thus reducing the degree of crystallinity. It was found that the manufacturing method of the present invention can be used not only for the low-purity cellulose material that is normally used, but also for the high-purity cellulose material. Furthermore, the xylose concentration in the constituent sugars of the fibrous cellulose molded bodies in prototypes 1 to 11 was 0.1 to 20% by weight in all cases, and was contained at a concentration relatively close to the xylose concentration in the constituent sugars of the raw material pulp. Thus, it was found that since the xylose in the constituent sugars of the raw material is contained in the molded body with almost no loss during the dissolution, molding, and drying processes, the xylose concentration in the constituent sugars of the molded body depends on the xylose concentration in the constituent sugars of the raw material.

[0114] Of the cellulose molded articles of prototypes 1 to 11, prototypes 1 to 6 exhibit excellent transparency and can be appropriately used as materials for cellulose products. Furthermore, since prototypes 1 to 6 have a crystallinity of 60% or less, they also have good performance in terms of flexibility, dyeability, and chemical reactivity in post-processing.

[0115] Based on a comprehensive comparison of the cellulose molded articles of prototype examples 1 to 11, it is preferable that the conditions for the manufacturing method of the cellulose molded article of the present invention be such that the temperature of the molding aqueous solution is 10°C or higher and the concentration of the cellulose solvent in the molding aqueous solution is 20% or higher. Considering the cost of maintaining the temperature and the ease with which the cellulose solution solidifies, it is considered preferable that the temperature of the molding aqueous solution be around 10 to 70°C and the concentration of the cellulose solvent be around 20 to 50%. Furthermore, as mentioned above, a wide range of cellulose materials from low-purity to high-purity cellulose materials can be selected for use in the manufacturing method of the present invention. Specifically, cellulose materials with a xylose concentration of about 0.1 to 20% by weight in the constituent sugars can be selected.

[0116] As described above, according to the manufacturing method of the present invention, by appropriately adjusting the cellulose solvent concentration and temperature in the molding aqueous solution within the above range, a low-crystallinity cellulose molded article with excellent transparency can be produced from raw materials of a wide range of purities. Furthermore, since the cellulose purity of the cellulose molded article depends on the cellulose purity of the raw material, it has been difficult to obtain a molded article with high purity and low crystallinity using conventional techniques. However, by using the manufacturing method of the present invention, it is possible to mold a cellulose molded article with high purity and low crystallinity, thereby providing a cellulose molded article that achieves both safety and various performance characteristics. [Industrial applicability]

[0117] The present invention provides a method for producing cellulose molded articles that allows for the production of not only conventional low-crystalline cellulose molded articles with low cellulose purity, but also low-crystalline cellulose molded articles with high cellulose purity. In particular, the high-purity low-crystalline cellulose molded articles can provide product materials that meet various safety test requirements. Furthermore, the obtained low-crystalline cellulose molded articles have high transparency, flexibility, and excellent dyeability, making them suitable for a wide range of applications such as cosmetics, textiles, and packaging materials. When the molded article is a film, its affinity with reactive agents such as laminating agents and surface coating agents improves, enhancing its performance as a film. When the molded article is a bead, its reactivity with hydrophobic coating agents required for incorporation into foundations and the like improves, enhancing its performance as a bead. Moreover, the obtained cellulose molded articles can be suitably used as industrial raw materials with excellent chemical reactivity.

Claims

1. The cellulose material is pulp mainly composed of cellulose, and contains 0.1 to 20% by weight of xylose as a constituent sugar. A cellulose dissolution step in which the cellulose material is dissolved in a cellulose solvent to obtain a cellulose solution, A molding step in which a wet molded body is produced by discharging the cellulose solution into a molding aqueous solution containing 20 to 50% of the cellulose solvent at a temperature of 10 to 70°C, A drying process in which the wet molded body is washed and then dried to obtain a cellulose molded body having a degree of crystallinity of 60% or less, represented by the following formula (i). A method for producing a cellulose molded article, characterized by having the following: [Math 1] Ic: Diffraction intensity of the cellulose type II crystal lattice plane ((1-10) plane, peak value around 2θ = 13°) Ia1: Diffraction intensity at the point where the line connecting the diffraction intensities at 2θ = 8° and 15° intersects with the line drawn perpendicularly from 13°. Ia2: Diffraction intensity of the amorphous region (2θ = 15°)

2. The method for producing a cellulose molded article according to claim 1, wherein the cellulose solvent contains a tetraalkylammonium acetate represented by the following formula (Fi) and an aprotic polar solvent, and the content of the aprotic polar solvent is 55% by weight or more. 【Chemistry 1】 In the formula, R １ , R ２ , R ３ and R ４ Each of these independently represents an alkyl group having 3 to 6 carbon atoms.

3. The method for producing a cellulose molded article according to claim 2, wherein the hydrogen bond accepting ability (β value) of the Kamlet-Taft parameter of the cellulose solvent is 0.8 to 1.

3.

4. The method for producing a cellulose molded article according to claim 2, wherein the tetraalkylammonium acetate is tetrabutylammonium acetate.

5. The method for producing a cellulose molded article according to claim 2, wherein the number of donors of the aprotic polar solvent is 20 to 50.

6. The method for producing a cellulose molded article according to claim 2, wherein the aprotic polar solvent is at least one selected from amide solvents, sulfoxide solvents, and pyridine solvents.

7. The method for producing a cellulose molded article according to claim 2, wherein the aprotic polar solvent is at least one selected from the group consisting of N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, N,N-diethylacetamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone, N,N'-dimethylpropyleneurea, 1,3-dimethyl-2-imidazolidinone, tetramethylurea, tetraethylurea, pyridine, and 4-methylpyridine, and derivatives thereof.

8. The method for producing a cellulose molded article according to claim 1, wherein the cellulose molded article is in the form of a fiber, film, or sphere.

9. The method for producing a cellulose molded article according to claim 2, wherein the cellulose molded article is in the form of a fiber, film, or sphere.

10. The method for producing a cellulose molded article according to claim 7, wherein the cellulose molded article is in the form of a fiber, film, or sphere.

11. The cellulose material is pulp mainly composed of cellulose, and contains 0.1 to 20% by weight of xylose as a constituent sugar. A cellulose dissolution step in which the cellulose material is dissolved in a cellulose solvent to obtain a cellulose solution, A molding step in which a wet molded body is produced by discharging the cellulose solution into a molding aqueous solution containing 20 to 50% of the cellulose solvent at a temperature of 10 to 70°C, A cellulose molded body obtained by washing the wet molded body and then drying it in a drying step, The cellulose molded body is characterized in that it contains 0.1 to 20% by weight of xylose as a constituent sugar, and the degree of crystallinity of the cellulose molded body represented by the following formula (i) is 60% or less. [Math 2] Ic: Diffraction intensity of the cellulose type II crystal lattice plane ((1-10) plane, peak value around 2θ = 13°) Ia1: Diffraction intensity at the point where the line connecting the diffraction intensities at 2θ = 8° and 15° intersects with the line drawn perpendicularly from 13°. Ia2: Diffraction intensity of the amorphous region (2θ = 15°)

12. The cellulose molded article according to claim 11, wherein the cellulose solvent contains a tetraalkylammonium acetate represented by the following formula (Fi) and an aprotic polar solvent, and the content of the aprotic polar solvent is 55% by weight or more. 【Chemistry 2】 In the formula, R1, R2, R3, and R4 each independently represent an alkyl group having 3 to 6 carbon atoms.

13. The cellulose molded article according to claim 12, wherein the hydrogen bond accepting ability (β value) of the Kamlet-Taft parameter of the cellulose solvent is 0.8 to 1.

3.

14. The cellulose molded article according to claim 12, wherein the aprotic polar solvent is at least one selected from the group consisting of N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, N,N-diethylacetamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone, N,N'-dimethylpropyleneurea, 1,3-dimethyl-2-imidazolidinone, tetramethylurea, tetraethylurea, pyridine, and 4-methylpyridine, and derivatives thereof.

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