Manufacturing method of cellulose molding and cellulose molding

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 cellulosic moulded body and to a cellulosic moulded body. [Background technology]

[0002] Generally, cellulose is produced by the viscose process, in which a cellulose material such as pulp is immersed in an alkaline solution such as sodium hydroxide to form alkali cellulose, which is then sulfurized with carbon disulfide and further dissolved in an alkaline solution to produce viscose, which is then coagulated with an acid solution such as sulfuric acid. The cellulose produced in this manner is formed into an appropriate molded product in the form of fibers, films, spheres, etc., depending on the shape of the product when coagulated, and is processed into various products such as paper products, clothing, and sanitary goods.

[0003] The viscose process requires many steps to prepare viscose from cellulose materials, which requires a lot of equipment and time. In addition, there are issues with improving work efficiency and reducing the environmental load, such as exhaust gas treatment and waste liquid treatment using alkaline solutions, acid solutions, hydrogen sulfide, etc. Furthermore, because the work environment is subject to the presence of sulfur gas due to the sulfurization process, cleaning, desulfurization, etc., it is essential that workers 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 a process of producing viscose from the cellulose material (see, for example, Patent Document 1). In this production method, the cellulose material is dissolved in a mixed solvent containing an ionic liquid such as an imidazolium salt and an aprotic polar solvent to produce a cellulose solution, and the cellulose solution is then solidified to obtain a cellulose film. This reduces the number of steps, reducing the burden on equipment and improving work efficiency, while also improving safety measures and reducing the environmental load by eliminating a work environment where sulfur gas is present.

[0005] Also, a production 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 a cellulose material (see, for example, Patent Documents 2, 3, and 4). The mixed solvent used in this production method is tetrabutylammonium acetate, which has a higher dissolution efficiency than an ionic liquid and is inexpensive, and therefore can improve productivity.

[0006] However, all of the above methods for producing cellulose molded bodies by directly dissolving cellulose materials are methods for producing cellulose films. However, cellulose molded bodies can be obtained in any suitable form, such as fibers or spheres, other than films. Of the resulting molded bodies, films are mainly used for packaging materials, fibers are mainly used for cosmetics and textiles, and spheres (beads) are mainly used for cosmetics, etc.

[0007] Generally, cellulose molded bodies for cosmetics are required to have properties appropriate for their intended use, such as transparency and flexibility, cellulose molded bodies for textiles are required to have dyeability, and cellulose molded bodies for packaging materials are required to have transparency. In these cellulose molded bodies, the refractive index of light differs between the crystalline and non-crystalline parts of cellulose, so the higher the degree of crystallinity, the more diffusely reflected light there is, and the lower the degree of crystallinity, the better the transparency and flexibility. In addition, the non-crystalline parts are more susceptible to impregnation with dyes and chemicals, and therefore have 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 in which pulp containing a high concentration of hemicellulose, whose constituent sugars are xylose and the like, is used as the cellulose raw material (see, for example, Patent Document 5). However, in the above manufacturing method, in order to obtain cellulose fibers with low crystallinity, it is necessary to adjust the xylose concentration in the constituent sugars of the raw material itself, and it is difficult to arbitrarily adjust the degree of crystallinity.

[0009] In addition, since the cellulose fibers obtained by the above manufacturing method contain a high concentration of xylose as a constituent sugar, when used in sanitary products such as nonwoven gauze, there is a possibility that the safety standards for sanitary materials will not be met. In the medical nonwoven gauze standard conforming to the JIS L 1912 (1997) medical nonwoven fabric test method, the distillation residue, which is one of the chemical requirements, is stipulated as follows: when the nonwoven fabric is boiled in water and the resulting solution is evaporated, the weight of the substance that remains undistilled is 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 dissolved in hot water, so there is a risk of exceeding the standard for distillation residue.

[0010] Therefore, the inventors have intensively studied a method for producing a cellulose molded body that can control the crystallinity of cellulose regardless of the xylose concentration in the constituent sugar of the raw material. As a result, they have invented a method that can obtain a low-crystalline cellulose molded body regardless of the xylose concentration in the constituent sugar of the raw material 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] JP 2011-184541 A [Patent Document 2] JP 2015-074704 A [Patent Document 3] JP 2015-093876 A [Patent Document 4] JP 2016-196526 A [Patent Document 5] Special Publication No. 2021-517214 Summary of the Invention [Problem to be solved by the invention]

[0012] The present invention has been developed in consideration of the above-mentioned points, and provides a method for producing a cellulose molded body and a cellulose molded body that can obtain a low-crystalline cellulose molded body by adjusting the molding conditions regardless of the xylose concentration in the constituent sugars of the cellulose material. [Means for solving the problem]

[0013] That is, the first invention relates to a method for producing a cellulose molded body, which comprises a cellulose dissolving step of dissolving a cellulose material in a cellulose solvent to obtain a cellulose solution, a molding step of discharging the cellulose solution into an aqueous molding solution at 10 to 70°C containing 20 to 50% of the cellulose solvent to produce a wet molded body, and a drying step of washing and drying the wet molded body to obtain a cellulose molded body.

[0014] A second invention relates to a method for producing a cellulose molded body according to the first invention, wherein the cellulose material is pulp containing cellulose as a main component and contains 0.1 to 20% by weight of xylose as a constituent sugar.

[0015] The third invention relates to a method for producing a cellulose molded body according to the first or second invention, 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.

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

[0017] A fourth invention relates to the method for producing a cellulose molded article according to the third invention, wherein the cellulose solvent has a hydrogen bond accepting capacity (β value) of Kamlet-Taft parameters of 0.8 to 1.3.

[0018] A fifth invention relates to the method for producing a cellulose molded article according to the third invention, wherein the tetraalkylammonium acetate is tetrabutylammonium acetate.

[0019] A sixth invention relates to the method for producing a cellulose molded article according to the third invention, wherein the aprotic polar solvent has 20-50 donors.

[0020] A seventh invention relates to the method for producing a cellulose molded body according to the third invention, wherein the aprotic polar solvent is at least one selected from the group consisting of amide-based solvents, sulfoxide-based solvents, and pyridine-based solvents.

[0021] The eighth invention relates to a method for producing a cellulose molded body according to the third invention, 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, dimethylsulfoxide, N-methyl-2-pyrrolidone, N,N'-dimethylpropyleneurea, 1,3-dimethyl-2-imidazolidinone, tetramethylurea, tetraethylurea, pyridine, 4-methylpyridine, and derivatives thereof.

[0022] A ninth aspect of the present invention relates to a method for producing a cellulose molded article according to the first aspect of the present invention, wherein the cellulose molded article is in any one of a fibrous, film-like and spherical form.

[0023] A tenth aspect of the present invention relates to the method for producing a cellulose molded article according to the third aspect of the present invention, wherein the cellulose molded article is in any one of a fibrous, film-like and spherical form.

[0024] An eleventh aspect of the present invention relates to the method for producing a cellulose molded article according to the eighth aspect of the present invention, wherein the cellulose molded article is in any one of a fibrous, film-like and spherical form.

[0025] The twelfth invention relates to a cellulose molded body obtained through a cellulose dissolving process in which a cellulose material is dissolved in a cellulose solvent to obtain a cellulose solution, a molding process in which the cellulose solution is discharged into an aqueous molding solution at 10 to 70°C containing 20 to 50% of the cellulose solvent to produce a wet molded body, and a drying process in which the wet molded body is washed and then dried, wherein the cellulose molded body has a crystallinity represented by the following formula (i) of 60% or less.

[0026]

number

[0027] A thirteenth aspect of the present invention relates to the cellulose molded product according to the twelfth aspect of the present invention, which contains 0.1 to 20% by weight of xylose as a constituent sugar.

[0028] The 14th invention relates to a cellulose molded body according to the 12th or 13th invention, wherein 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] A fifteenth aspect of the present invention relates to the cellulose molded article according to the fourteenth aspect of the present invention, wherein the cellulose solvent has a hydrogen bond accepting capacity (β value) of Kamlet-Taft parameters of 0.8 to 1.3.

[0030] The sixteenth invention relates to the cellulose molded body according to the fourteenth invention, 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, dimethylsulfoxide, N-methyl-2-pyrrolidone, N,N'-dimethylpropyleneurea, 1,3-dimethyl-2-imidazolidinone, tetramethylurea, tetraethylurea, pyridine, 4-methylpyridine, and derivatives thereof. Effect of the Invention

[0031] The method for producing a cellulose molded body of the first invention includes a cellulose dissolving step in which a cellulose material is dissolved in a cellulose solvent to obtain a cellulose solution, a molding step in which the cellulose solution is discharged into an aqueous molding solution at 10 to 70°C containing 20 to 50% of the cellulose solvent to produce a wet molded body, and a drying step in which the wet molded body is washed and then dried to obtain a cellulose molded body.Therefore, it is possible to provide a low-crystalline cellulose molded body 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 body of the second invention, in the first invention, the cellulose material is a pulp whose main component is cellulose and contains 0.1 to 20% by weight of xylose as a constituent sugar, making it possible to use raw materials with high cellulose purity that have not previously been used as raw materials for low-crystalline cellulose molded bodies, and by expanding the range of raw materials to be used, the range of uses for the obtained molded bodies can be expanded.

[0033] According to the third invention, the method for producing a cellulose molded body of 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, regardless of the crystalline form of the cellulose material, the cellulose material can be dissolved uniformly in a short time without performing a pretreatment process, 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 body 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 dissolved uniformly in a short time without relying on the crystalline form of the cellulose material and without performing a pretreatment process, 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 body of the fifth invention, since the tetraalkylammonium acetate in the third invention is tetrabutylammonium acetate, the dissolution efficiency of the cellulose material is excellent.

[0036] According to the sixth invention, in the method for producing a cellulose molded body, in the third invention, the aprotic polar solvent has a donor number of 20 to 50, so that it has good compatibility with tetraalkylammonium acetate and the solubility of the cellulose material is good.

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

[0038] According to the eighth invention, the method for producing a cellulose molded body of 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, dimethylsulfoxide, N-methyl-2-pyrrolidone, N,N'-dimethylpropyleneurea, 1,3-dimethyl-2-imidazolidinone, tetramethylurea, tetraethylurea, pyridine, 4-methylpyridine, and derivatives thereof, and therefore can be procured cheaply and easily, which is advantageous in terms of economy, mass production, etc.

[0039] According to the method for producing a cellulose molded body of the ninth invention, in the first invention, the cellulose molded body is in the form of any one of fibers, films, or spheres, making it easy to produce the molded body and process it into products.

[0040] According to the method for producing a cellulose molded body of the tenth invention, in the third invention, the cellulose molded body is in the form of any one of fibers, films, or spheres, making it easy to produce the molded body and process it into products.

[0041] According to the method for producing a cellulose molded body of the 11th invention, in the seventh invention, the cellulose molded body is in the form of any one of fibers, films, or spheres, making it easy to produce the molded body and process it into products.

[0042] The cellulose molded body of the twelfth invention is a cellulose molded body obtained through a cellulose dissolving process in which a cellulose material is dissolved in a cellulose solvent to obtain a cellulose solution, a molding process in which the cellulose solution is ejected into an aqueous molding solution at 10 to 70°C containing 20 to 50% of the cellulose solvent to produce a wet molded body, and a drying process in which the wet molded body is washed and then dried.Since the crystallinity of the cellulose molded body is 60% or less, it has good various performance properties such as transparency when wet, flexibility, dyeability, and chemical reactivity in post-processing, and can be suitably used as a molding material for a wide variety of cellulose products according to their shapes.

[0043] According to the cellulose molded body of the 13th invention, in the 12th invention, the cellulose molded body contains 0.1 to 20% by weight of xylose as a constituent sugar, so that in addition to cellulose molded bodies with low cellulose purity, cellulose molded bodies with high cellulose purity and conforming to various safety standards can be provided.

[0044] According to the cellulose molded body 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, so that the cellulose material can be dissolved uniformly in a short time without relying on the crystalline form of the cellulose material and without performing a pretreatment process, and the fluidity of the cellulose solution obtained by dissolving the cellulose material is increased, thereby improving the processability of the molded body.

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

[0046] According to the cellulose molding 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, dimethylsulfoxide, N-methyl-2-pyrrolidone, N,N'-dimethylpropyleneurea, 1,3-dimethyl-2-imidazolidinone, tetramethylurea, tetraethylurea, pyridine, 4-methylpyridine, and derivatives thereof, and therefore can be procured cheaply and easily, which is advantageous in terms of economy, mass production, etc. [Brief description of the drawings]

[0047] [Figure 1] 1 is a schematic process diagram of a method for producing a cellulose moulded body according to an embodiment of the present invention; FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0048] The method for producing a cellulose molded body according to one embodiment of the present invention shown in Figure 1 is a method for obtaining a low-crystalline cellulose molded body regardless of the xylose concentration in the constituent sugars of the cellulose material, and includes a cellulose dissolving process, a molding process, and a drying process.

[0049] The cellulose molded body 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 it into any of the following shapes: fiber, film, and sphere. In particular, the cellulose molded body is a so-called cellulose fiber, and can be widely used as a material for processed products such as nonwoven fabrics. In the following description, the cellulose molded body will be described as cellulose fiber (fibrous cellulose) unless otherwise specified.

[0050] The cellulose dissolving process is a process in which a cellulose material is dissolved in a cellulose solvent to obtain a cellulose solution. The cellulose material is a material containing a cellulose component, and includes natural materials such as pulp and cotton, and processed materials such as paper products. Among natural materials, pulp is easily available and is preferably used as a cellulose material. In the case of processed materials, it is preferable to reuse discarded paper products and the like among materials that have been processed into products, from the viewpoint of reducing environmental load.

[0051] Pulp is a fibrous material obtained mainly by crushing wood and removing impurities. In general, pulp used as a raw material for low-crystalline cellulose molded bodies is often pulp containing cellulose and xylose as a constituent sugar at a high concentration obtained by removing impurities such as lignin. In the method for producing a cellulose molded body 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-crystalline cellulose molded bodies. That is, in addition to pulp with a low cellulose purity that is usually used when producing a low-crystalline cellulose molded body, pulp with a high cellulose purity can also be used. Therefore, not only the range of raw materials to be used is expanded, but also the use applications of the obtained molded body can be expanded.

[0052] In addition, when xylose is contained in a cellulose solution described later, it inhibits the crystallization of cellulose when the cellulose solution solidifies, so it can also be added to control the crystallinity of cellulose as desired. A cellulose molded body with a high degree of crystallinity has increased rigidity and decreased transparency, while a low degree of crystallinity has flexibility and improved transparency, so the content can be adjusted appropriately 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] The cellulose solvent is a solvent for dissolving cellulose materials such as pulp, and in particular, a solvent that can dissolve pulp uniformly in a short time without relying on the crystal form of the pulp and without a pretreatment process is used. From the viewpoint of reducing the environmental load, it is preferable that the cellulose solvent does not contain halogen as an anion. 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 or different alkyl groups. If the alkyl group has 2 or less carbon atoms or 7 or more carbon atoms, the solubility of the solvent in the pulp may decrease.

[0056] The Kamlet-Taft parameters are used as an evaluation index of the solvent properties of a cellulose solvent. The Kamlet-Taft parameters include three parameters, namely hydrogen bond acidity (α), hydrogen bond basicity (β), and dipolarity / polarizability (π), and the hydrogen bond basicity (β) is related to cellulose dissolving ability. The cellulose dissolving ability required in the present invention 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 dissolved uniformly in a short time without a pretreatment step, regardless of the crystal 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 for efficiently dissolving cellulosic materials such as pulp. The tetraalkylammonium acetate is any one or a combination of tetrabutylammonium acetate, tetrapropylammonium acetate, tetrapentylammonium acetate, and tetrahexylammonium acetate.

[0058] Among the above tetraalkylammonium acetates, tetrabutylammonium acetate is preferably selected because it has excellent dissolving efficiency for polysaccharides. Tetrabutylammonium acetate is an ionic ammonium acetate salt having an alkyl group with 4 carbon atoms, and has a good balance between affinity for hydrogen bonds and hydrophobicity as an organic substance. Due to this property, it is believed that it penetrates between crystalline cellulose in pulp to break hydrogen bonds between and within molecules, and that re-aggregation is suppressed by the action of hydrophobic groups in the molecule. Therefore, it is possible to efficiently dissolve cellulose crystals, which are the main component of pulp.

[0059] The aprotic polar solvent is a solvent for dissolving tetraalkylammonium acetate such as tetrabutylammonium acetate, which is solid at room temperature. The aprotic polar solvent enables homogeneous dissolution of tetraalkylammonium acetate in a short time, and can reduce the viscosity of the cellulose solution obtained by dissolving pulp, which will be described later, to appropriately adjust the fluidity.

[0060] In addition, the tetraalkylammonium acetate constituting the cellulose solvent has a strong electric charge, and therefore easily bonds electrostatically with the pulp having a large number of hydroxyl groups in the molecule through hydrogen bonds, etc. If a protic solvent is used, an interaction (hydrogen bond) with the tetraalkylammonium acetate occurs, which inhibits the cleavage of the hydrogen bonds of the cellulose by the tetraalkylammonium acetate, and therefore an aprotic catalyst is preferred. Furthermore, if a non-polar (non-polar) solvent is used, it is difficult to dissolve the tetraalkylammonium acetate, so a polar solvent is preferred. Therefore, the solvent used for the cellulose solvent is preferably an aprotic polar solvent.

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

[0062] The aprotic polar solvent preferably has a strong hydrogen bond acceptor property and a solubility parameter similar to that of tetraalkylammonium acetate. Therefore, the aprotic polar solvent preferably has a donor number of 20 to 50, more preferably 25 to 40, and even more preferably 25 to 35. The donor number is one of the indicators of the basicity of a solvent, and is a value expressed as -ΔH (kcal / mol) of the reaction heat (enthalpy) when a solvent molecule reacts 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 property of the aprotic polar solvent may decrease, resulting in a decrease in the solubility of the pulp, and if the donor number is too large, the compatibility of the aprotic polar solvent with tetraalkylammonium acetate may decrease.

[0063] In addition, as the aprotic polar solvent, from the viewpoint of the solubility of tetraalkylammonium acetate and pulp, at least one selected from amide solvents, sulfoxide solvents, and pyridine solvents is preferably used. Specifically, at least one selected from the group consisting of N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, N,N-diethylacetamide, dimethylsulfoxide, N-methyl-2-pyrrolidone, N,N'-dimethylpropyleneurea, 1,3-dimethyl-2-imidazolidinone (N,N'-dimethylethyleneurea), tetramethylurea, tetraethylurea, pyridine, 4-methylpyridine, and derivatives thereof is preferably used. These are relatively inexpensive and easy to procure, and therefore are preferable from the viewpoint of economy, mass production, and the like.

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

[0065] These aprotic polar solvents can be used alone or in combination of two or more. For example, when two or more types are used in combination, at least one of them should be an aprotic polar solvent having a donor number of 20 to 50, and the other aprotic polar solvent to be combined may be an aprotic polar solvent 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 in which pulp is dissolved by reducing the content of tetraalkylammonium acetate in the cellulose solvent. When the fluidity of the cellulose solution is increased, the processability of the molded body is improved. The upper limit of the content of the aprotic polar solvent is not particularly limited as long as a trace amount of tetraalkylammonium acetate is mixed, and is not 100% by weight. The upper limit of the content of the aprotic polar solvent is, for example, 90 to 99% by weight. If the content of the aprotic polar solvent is too low, the cellulose solvent becomes a slurry and the fluidity decreases, which may deteriorate the fluidity and homogeneity of the cellulose solution in which pulp is dissolved. If the content is too high, the solubility of the pulp may decrease.

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

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

[0069] The pulp (cellulose) in the cellulose solvent reacts with acetate ions (CH3COO - ) breaks the hydrogen bonds of cellulose, and acetate ions (CH3COO - ) and forms hydrogen bonds with the oxygen in cellulose and the macrocation ([DMSO+TAA] + ) forms a weak interaction with cellulose. As a result, it is believed that cellulose exists in the solvent in the form shown in formula (Fii) below. Therefore, it is believed that cellulose can be dissolved uniformly in a short time without relying on the crystal form of cellulose and without a pretreatment step.

[0070] [ka]

[0071] The cellulose solution is a solution obtained by dissolving a predetermined amount of pulp in the cellulose solvent. The pulp dissolved in the cellulose solvent is set according to the degree of polymerization, the degree of crystallinity, etc., but from the viewpoint of production efficiency, such as easy preparation of the cellulose solution with low burden and easy coagulation, the amount added is preferably about 3 to 15% by weight based on the weight of the cellulose solvent. If the concentration of the pulp is too low, the time required for coagulation in the molding process described below increases, and handling during processing and treatment may become difficult. If the concentration is too high, the viscosity of the cellulose solution increases, taking a long time to dissolve the pulp, and a large amount of tetraalkylammonium acetate is required, which may be economically and efficiently disadvantageous.

[0072] When dissolving pulp in a cellulose solvent, it is preferable to set the dissolution temperature to a relatively mild temperature condition. The lower limit of the dissolution temperature is set to be equal to or higher than the solidification temperature of the aprotic polar solvent used, for example, about 20°C, from the viewpoint of ensuring the fluidity of the cellulose solvent and the reactivity of the pulp with the tetraalkylammonium acetate. On the other hand, the upper limit of the dissolution temperature is set to, for example, about 50°C, from the viewpoint of suppressing excessive reaction between the pulp and the tetraalkylammonium acetate to control the reaction and reducing the equipment required for heating. Since the temperature at which the pulp is dissolved in the cellulose solvent is in a mild temperature range, the work can be performed at room temperature, or even if heating is performed, a simple heating device or the like is sufficient, so that no special heating equipment is required and the equipment costs required for production can be reduced. In addition, the evaporation of the components of the cellulose solvent can be suppressed, and the safety of the working environment is also improved. Although it is possible to shorten the reaction time by increasing the dissolution temperature, it is not preferable to increase 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] In the cellulose solution, additives such as antioxidants, plasticizers, fillers, ultraviolet absorbers, pigments, antistatic agents, other polymeric materials, etc. may be added as necessary when dissolving the pulp in the cellulose solvent. The amount of the additive added is appropriately determined depending on the type and application of the additive.

[0074] The cellulose solution is prepared by adding pulp, cellulose solvent, and additives, etc., at a predetermined mixing ratio, and stirring appropriately. For example, mechanical stirring or ultrasonic vibration is suitable for stirring the materials when the pulp content is relatively low and the fluidity of the cellulose solution is high, and a twin-screw kneading extruder or kneader is suitable for stirring the materials when the pulp content is relatively high and the viscosity of the cellulose solution is high. The stirring time depends on the fluidity of the solution, and is preferably about 10 to 90 minutes, for example. If the stirring time is too short, it is difficult to dissolve the pulp sufficiently. In addition, if the stirring time is longer than necessary, the physical properties are not improved, so the stirring time is terminated at an appropriate time. By stirring the materials, the dissolution of the pulp is promoted and the uniformity of the solution can be improved. The dissolution of the pulp may be performed in an inert gas. This suppresses the decrease in the degree of polymerization of the cellulose in the pulp.

[0075] The molding process is a process in which the cellulose solution obtained in the cellulose dissolving process is molded into a wet compact (fibrous wet compact), and the wet compact is produced by discharging the cellulose solution into an aqueous molding solution at 10 to 70° C. The wet compact (fibrous wet compact) is an intermediate product of the cellulose compact (cellulose fiber) that is finally obtained.

[0076] The cellulose solution is discharged using a known discharge device that corresponds to the desired shape of the molded product. For example, a spunbond die or a meltblowing die is used to mold cellulose fibers. A T-die or an inflation die is used to mold cellulose films. An atomizer or a spray dryer is used to mold cellulose beads.

[0077] The aqueous solution for molding is an aqueous solution containing 20 to 50% of the same cellulose solvent as that used in the cellulose dissolving process, and is solidified by contact with the cellulose solution. The materials constituting the aqueous solution for molding are cellulose solvent and ion-exchanged water. If the content of the cellulose solvent is too low, the solidification speed of the discharged cellulose solution is high and the crystallization of cellulose is likely to proceed, so that the degree of crystallization may be too high. On the other hand, if the content is too high, the solidification of the cellulose solution may be insufficient, making molding difficult.

[0078] The reaction conditions for the cellulose solution and the aqueous molding solution are about 10 to 70° C., preferably 10 to 40° C. If the temperature of the aqueous molding solution is too high, the solution will solidify rapidly, which may reduce the density and strength of the cellulose molded body. In addition, the energy cost for maintaining the temperature of the aqueous molding solution will increase.

[0079] When the cellulose solution is discharged into the aqueous forming solution, it is solidified by the aqueous forming solution, and a transparent wet molded body (fibrous wet molded body) consisting of the cellulose components and the remaining cellulose solvent is obtained. Meanwhile, the cellulose solvent components (tetraalkylammonium acetate, aprotic polar solvent) that have separated from the cellulose and dissolved into the aqueous forming solution are recovered by fractional distillation or the like. After recovery, they are filtered, purified, and otherwise processed to be reused as a cellulose solvent.

[0080] The drying step is a step in which the wet compact (fibrous wet compact) obtained in the molding step is washed and then dried to obtain a cellulose compact (fibrous cellulose). The wet compact is washed by contacting the wet compact with a washing liquid such as water in a room temperature environment of about 20 to 30°C, thereby replacing the cellulose solvent in the wet compact with the washing water and separating it. As the washing water, a solvent that has high affinity for cellulose and does not dissolve it is preferable, and water that is easily available is particularly preferable. From the viewpoint of more reliably removing components other than cellulose from the wet compact, this washing is preferably performed multiple times (about twice).

[0081] The washed wet body is appropriately dried to obtain a cellulose body (fibrous cellulose). The drying method is not particularly limited as long as the washed wet body can be dried, and may be, for example, natural drying at room temperature, drying with a drying means such as a heated roll or hot air, or the like. In addition, since no exhaust gas is generated in this drying process, there is no need to treat exhaust gas such as sulfide gas, which is performed in the viscose method.

[0082] In the method for producing cellulose molded bodies of the present invention, the cellulose solvent used to directly dissolve the cellulose material is separated from the cellulose components in the molding step as described above, and therefore the cellulose solvent can be separated into water and the cellulose solvent by fractional distillation of the aqueous molding solution during the treatment step, and the recovered cellulose solvent can be reused to dissolve the cellulose material. Therefore, when producing cellulose molded bodies continuously, the amount of cellulose solvent used can be reduced by only replenishing the amount that is inevitably consumed, which is economical and reduces the environmental load.

[0083] In the method for producing a cellulose molded body of the present invention, a cellulose solution in which a cellulose material is dissolved is brought into contact with a forming aqueous solution in which the concentration of the cellulose solvent and the temperature of the aqueous solution have been adjusted, whereby a cellulose molded body with low crystallinity can be easily molded. In the molding process, the cellulose solution is discharged into the forming aqueous solution by a discharge method corresponding to the desired shape, such as fiber, film, or sphere, to obtain a cellulose molded body of any shape.

[0084] The low-crystalline cellulose molded body of the present invention has good properties such as transparency when wet, flexibility, dyeability, and chemical reactivity in post-processing. The crystallinity of this cellulose molded body is preferably 60% or less. The crystallinity indicates the proportion of crystalline components in the cellulose molded body and affects physical properties such as transparency and strength. Since the crystal form in the molded body is not constant, the transparency of the cellulose molded body varies slightly depending on the crystal form, but generally the lower the crystallinity, the more the transparency of the cellulose molded body tends to improve.

[0085] The cellulose molded body obtained by the manufacturing method of the present invention has a cellulose type II crystal structure. In general, natural cellulose materials such as pulp have a cellulose type I crystal structure. On the other hand, when natural cellulose materials are mercerized or dissolved in a cellulose solvent to be regenerated, the crystal structure changes to cellulose type II. Therefore, the crystallinity can be calculated by X-ray diffraction measurement using the following formula (i). In formula (i), Ic is the diffraction intensity of the crystal lattice plane of cellulose type II ((1-10) plane, peak value near 2θ=13°), Ia1 is the diffraction intensity at the intersection of the line connecting the diffraction intensities at 2θ=8° and 15° and the line vertically descending from 13°, and Ia2 is the diffraction intensity of the amorphous part (2θ=15°).

[0086]

number

[0087] The cellulose molded body of the present invention has a crystallinity of 60% or less, and thus has better properties such as transparency when wet, flexibility, dyeability, and chemical reactivity in post-processing. The transparency of the cellulose molded body contributes to the appearance. A cellulose molded body with high transparency has good design and aesthetic properties, and a clean-looking product can be obtained by processing the product. In this way, the cellulose molded body of the present invention is molded into a high-quality material with excellent transparency in any shape. Therefore, it can be suitably used as a molding material for a wide variety of cellulose products according to the shape of the cellulose molded body.

[0088] In addition, the low-crystalline cellulose molded body of the present invention contains 0.1 to 20% by weight of xylose as a constituent sugar, corresponding to the xylose concentration in the constituent sugar of the cellulose material used. This includes not only low-crystalline cellulose molded bodies obtained from ordinary raw materials with low cellulose purity, but also low-crystalline cellulose molded bodies obtained from raw materials with high cellulose purity. Cellulose molded bodies made of high purity cellulose contain a small amount of xylose as a constituent sugar in the molded body, so that they can be made into products that comply with safety standards such as standards for distillation residues.

[0089] Thus, the cellulose molded article of the present invention has good appearance such as designability and aesthetics due to its excellent transparency due to its low crystallinity, and is also safe because it is molded from high-purity cellulose. Therefore, products with a clean feel can be obtained by processing the product, and it is useful as a molding material for a wide range of products such as cosmetics such as face masks and medical supplies such as medical masks. EXAMPLES

[0090] [Preparation of cellulose molded body] When producing the cellulose molded bodies of prototype examples 1 to 11, 1,410 g of the cellulose solvent described below was placed in a 2 L separable flask, and 90 g of the cellulose material described below was added to the cellulose solvent. The cellulose was dissolved in a water bath at 55°C while stirring with a stirrer ("Logbone" manufactured by Kobelco Environmental Solutions Co., Ltd.) to obtain a cellulose solution.

[0091] Next, the same cellulose solvent as that used to dissolve the cellulose material was used to prepare aqueous solutions for molding with different blending ratios and aqueous solution temperatures, and the cellulose solution was discharged from a nozzle into the aqueous solution for molding using a gear pump (manufactured by Barmag; "Oerlikon") to solidify, thereby obtaining a fibrous wet molded body. The obtained wet molded body was washed with running water and then air-dried to obtain the fibrous cellulose molded bodies of Prototype Examples 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 a tetraalkylammonium acetate and 72% by weight of dimethylsulfoxide (manufactured by Kishida Chemical Co., Ltd.) as an aprotic polar solvent.

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

[0094] [Cellulose materials] Pulp 1: Dissolving pulp (Oji Paper Co., Ltd.; "LDKP"), xylose concentration in constituent sugars: 1.9% Pulp 2: Dissolving 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 sugar components: 0.3%

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

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

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

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

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

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

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

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

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

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

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

[0106] The fibrous cellulose molded bodies of Prototype Examples 1 to 11 were tested for the xylose concentration in the constituent sugar, the degree of crystallinity, and transparency when wet, and were judged to be good or bad. The test results for the cellulose molded bodies of Prototype Examples 1 to 11, as well as the xylose concentration in the constituent sugar of the cellulose material, the concentration of the cellulose solvent in the aqueous solution for molding, and the aqueous solution temperature, are shown in Table 1 below.

[0107] [Measurement of xylose concentration in constituent sugars] The fibrous cellulose bodies of Prototype Examples 1 to 11 were dissolved in 72% by weight sulfuric acid in a water bath at 30°C. Water was added to dilute the sulfuric acid to 4.5% by weight, and the mixture was treated in an oil bath at 120°C for 15 minutes to hydrolyze the sugar components in the cellulose bodies to monosaccharides. The xylose concentration (%) in the hydrolysis 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 to separate the sugars.

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

[0109] [Wet transparency test] For the fibrous cellulose molded bodies of Prototype Examples 1 to 11, fibers cut to a length of 50 mm were dispersed in water to form a slurry, which was then subjected to suction filtration to produce short fiber cylindrical sheet-shaped test specimens. 2 The resulting short fiber cylindrical sheet specimen was uniformly moistened by dripping ion-exchanged water onto it, and the moistened specimen was placed on a sheet with black characters printed on it, and the visibility (transparency) of the characters was judged visually. In judging the transparency, cases where the visibility of the characters was high (characters were easily visible) were rated as "○ (passable)," and cases where the visibility was low (characters were not easily visible) were rated as "× (unacceptable)."

[0110] [Table 1]

[0111] [Results and Discussion] Comparing prototypes 1, 3, and 8 (material: pulp 1, concentration: 20%), which had the same cellulose material and cellulose solvent concentration in the aqueous molding solution, it was found that the higher the temperature of the aqueous molding solution, the lower the crystallinity of the cellulose molded body. This is thought to be because when the cellulose solution is solidified in a high-temperature aqueous solution containing a cellulose solvent, the solid precipitates from the cellulose solution quickly, and precipitates before the cellulose can form a crystal lattice, increasing the non-crystalline portion and decreasing the crystallinity. Also, in prototype 8, where the temperature of the aqueous molding solution was 5°C, the visibility of the letters on which the test specimen was placed was low, and transparency was insufficient.

[0112] Comparing the prototypes 1, 7, 10 (material: pulp 1, temperature: 10°C), 2, 5 (material: pulp 2, temperature: 20°C), 3, 6 (material: pulp 1, temperature: 70°C), and 8, 9 (material: pulp 1, temperature: 5°C) in which the cellulose material and the temperature of the aqueous solution for molding were the same, it was found that the crystallinity tended to decrease as the concentration of the cellulose solvent in the aqueous solution for molding increased. This is because when the 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 crystallinity. In addition, in the prototypes 9, 10, and 11 in which the aqueous solution for molding did not contain cellulose solvent, the visibility of the letters on which the test specimen was placed was low and the transparency was insufficient, regardless of the temperature of the aqueous solution for molding. The transparency was also insufficient in the prototype 7 in which the concentration of the cellulose solvent was 10%.

[0113] Comparing Prototypes 3 and 4 (concentration: 20%, temperature: 70°C), which have the same cellulose solvent concentration in the aqueous solution for molding and the same temperature of the aqueous solution for molding, it was found that the higher the xylose concentration in the constituent sugar of the cellulose material, the lower the crystallinity. This is thought to be because the xylose contained as a constituent sugar inhibits the crystallization of cellulose when the cellulose solution solidifies, which reduces the crystallinity. It was found that the manufacturing method of the present invention can use not only low-purity cellulose materials that are usually used, but also high-purity cellulose materials. In addition, the xylose concentration in the constituent sugar of the fibrous cellulose molded bodies of Prototypes 1 to 11 was 0.1 to 20% by weight in all cases, which was relatively close to the xylose concentration in the constituent sugar of the raw material pulp. In this way, it was found that the xylose concentration in the constituent sugar of the raw material is contained in the molded body with almost no loss during the processes of dissolution, molding, and drying, and therefore the xylose concentration in the constituent sugar of the molded body depends on the xylose concentration in the constituent sugar of the raw material.

[0114] Among the cellulose molded bodies of Prototype Examples 1 to 11, Prototype Examples 1 to 6 have excellent transparency and can be appropriately used as materials for cellulose products. In addition, since the crystallinity of Prototype Examples 1 to 6 is 60% or less, the flexibility, dyeability, chemical reactivity in post-processing, and other properties are also good.

[0115] Judging comprehensively from the comparison of the cellulose molded bodies of Prototype Examples 1 to 11, the conditions for the manufacturing method of the cellulose molded body of the present invention are preferably a temperature of the aqueous molding solution of 10°C or higher and a concentration of the cellulose solvent in the aqueous molding solution of 20% or higher, and considering the cost of maintaining the temperature and the ease of solidification of the cellulose solution, it is considered that the temperature of the aqueous molding solution is preferably about 10 to 70°C and the concentration of the cellulose solvent is preferably about 20 to 50%. Also, as described above, the cellulose material that can be used in the manufacturing method of the present invention can be selected from a wide range of cellulose materials, from low-purity cellulose materials to high-purity cellulose materials, and specifically, a cellulose material with a xylose concentration in the constituent sugar of about 0.1 to 20% by weight 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 aqueous solution for molding within the above ranges, a cellulose molded body with excellent transparency and low crystallinity can be manufactured from raw materials with a wide range of purity. In addition, since the cellulose purity of the cellulose molded body depends on the cellulose purity of the raw material, it was difficult to obtain a molded body with high purity and low crystallinity using conventional techniques, but by using the manufacturing method of the present invention, it is possible to provide a cellulose molded body that is both safe and has various performances by molding a molded body with high purity and low crystallinity. [Industrial Applicability]

[0117] In the method for producing a cellulose molded body of the present invention, in addition to the conventional low crystalline cellulose molded body with low cellulose purity, a low crystalline cellulose molded body with high cellulose purity can be obtained, and in particular, a high purity low crystalline cellulose molded body can provide a product material that meets various safety tests. In addition, the obtained low crystalline cellulose molded body has high transparency, excellent flexibility and dyeability, and can be widely used in cosmetics, textiles, packaging materials, etc. In addition, when the molded body is a film, the affinity with reactants such as laminates and surface coating agents is improved, and the performance as a film is improved. In the case of beads, the reactivity with hydrophobic coating agents required when blended into foundations, etc. is improved, and the performance as beads is improved. Furthermore, the obtained cellulose molded body can be suitably used as an industrial raw material with excellent chemical reactivity.

Claims

1. The cellulose material is a pulp mainly composed of cellulose, and contains 0.1 to 20% by weight of xylose as a constituent sugar, a cellulose dissolving step of dissolving the cellulose material in a cellulose solvent to obtain a cellulose solution; a molding step of discharging the cellulose solution into an aqueous molding solution having a temperature of 10 to 70° C. and containing 20 to 50% of the cellulose solvent to produce a wet molded body; A drying step of washing the wet molded body and then drying it to obtain a cellulose molded body having a crystallinity of 60% or less, as represented by the following formula (i):

3. A method for producing a cellulose molded body comprising the steps of: [0010] Ic: Diffraction intensity of the crystal lattice plane of cellulose type II ((1-10) plane, peak value near 2θ = 13°) Ia1: Diffraction intensity at the intersection of a line connecting the diffraction intensities at 2θ=8° and 15° and a line vertically drawn from 13° Ia2: Diffraction intensity of amorphous part (2θ=15°)

2. 2. A method for producing a cellulose molded body 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 independently represents an alkyl group having 3 to 6 carbon atoms.

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

3.

4. 3. The method for producing cellulose moulded bodies according to claim 2, wherein the tetraalkylammonium acetate is tetrabutylammonium acetate.

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

6. 3. The method for producing a cellulose molded body according to claim 2, wherein the aprotic polar solvent is at least one selected from the group consisting of amide-based solvents, sulfoxide-based solvents, and pyridine-based solvents.

7. The method for producing a cellulose molded body 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, dimethylsulfoxide, N-methyl-2-pyrrolidone, N,N'-dimethylpropyleneurea, 1,3-dimethyl-2-imidazolidinone, tetramethylurea, tetraethylurea, pyridine, 4-methylpyridine, and derivatives thereof.

8. 2. The method for producing a cellulose molded body according to claim 1, wherein the cellulose molded body is in the form of any one of fibers, films, and spheres.

9. 3. The method for producing a cellulose molded body according to claim 2, wherein the cellulose molded body is in the form of any one of fibers, films, and spheres.

10. The method for producing a cellulose molded body according to claim 7, wherein the cellulose molded body is in the form of any one of fibers, films, and spheres.

11. The cellulose material is a pulp mainly composed of cellulose and contains 0.1 to 20% by weight of xylose as a constituent sugar, a cellulose dissolving step of dissolving the cellulose material in a cellulose solvent to obtain a cellulose solution; a molding step of discharging the cellulose solution into an aqueous molding solution having a temperature of 10 to 70° C. and containing 20 to 50% of the cellulose solvent to produce a wet molded body; A cellulose molded body obtained by washing the wet molded body and then drying the same, The cellulose shaped body is characterized in that it contains 0.1 to 20% by weight of xylose as a constituent sugar, and has a crystallinity represented by the above formula (i) of 60% or less.

12. The cellulose shaped article according to claim 11, wherein 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.

13. The cellulose molded article according to claim 12, wherein the hydrogen bond accepting capacity (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, dimethylsulfoxide, N-methyl-2-pyrrolidone, N,N'-dimethylpropyleneurea, 1,3-dimethyl-2-imidazolidinone, tetramethylurea, tetraethylurea, pyridine, 4-methylpyridine, and derivatives thereof.

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