Cellulose-based material
By controlling the crystallinity and surface coating of cellulose, the problems of cellulose aggregation and poor reactivity in liquids are solved, resulting in highly dispersible and reactive cellulose materials suitable for a variety of chemical reactions.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SEIKO EPSON CORP
- Filing Date
- 2026-01-30
- Publication Date
- 2026-08-04
AI Technical Summary
Existing technologies struggle to effectively suppress cellulose aggregation without affecting its reactivity, resulting in poor dispersibility and reactivity of cellulose in liquids.
By controlling the crystallinity of cellulose to below 50% and coating the hydroxyl groups on the surface of cellulose with aliphatic compounds, aromatic compounds or higher alcohols at a concentration of 0.1% to 20%, the reactivity and aggregation inhibition of cellulose can be adjusted.
It effectively inhibits aggregation while maintaining the reactivity of cellulose, improves the dispersibility and reactivity of cellulose in liquids, and is suitable as a raw material for various chemical reactions.
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Abstract
Description
Technical Field
[0001] This invention relates to a cellulose-based material. Background Technology
[0002] Cellulose is increasingly being used as a raw material for cellulose ethers, or as an industrial raw material for pharmaceuticals, cosmetics, food, biomass materials, etc.
[0003] In particular, the demand for low-environmental-impact materials has increased in recent years, leading to interest in cellulose as a natural material.
[0004] However, when cellulose is used as a raw material as described above, its reactivity is relatively poor, making it difficult for the desired reaction to proceed properly.
[0005] In addition, for the purpose of preventing cellulose from agglomerating in liquids, a technique for applying surface treatment to cellulose has been proposed (for example, see Patent Document 1).
[0006] However, when performing the surface treatment described above, it is difficult to sufficiently enhance the reactivity of cellulose. That is, in the prior art, it is difficult to achieve both reactivity and aggregation inhibition of cellulose.
[0007] Patent Document 1: Japanese Patent Application Publication No. 2019-178266 Summary of the Invention
[0008] The cellulose-based materials involved in the application examples of this invention contain: Cellulose, with a crystallinity of less than 50%; A coating material that coats the hydroxyl groups on the surface of the cellulose. The coating material is at least one selected from aliphatic compounds, aromatic compounds, and higher alcohols. The coating material achieves a coating rate of 0.1% or more and less than 20% of the hydroxyl groups on the surface of the cellulose. Attached Figure Description
[0009] Figure 1 A diagram illustrating a method for determining the hydroxyl coverage of the surface of cellulose achieved by a coating material.
[0010] Figure 2 This table summarizes the composition and evaluation results of the cellulose-based materials of Examples 1 to 9 and Comparative Examples 1 to 5. Detailed Implementation
[0011] The preferred embodiments of the present invention will now be described in detail.
[0012] [1] Cellulose-based materials First, the cellulose-based material of the present invention will be described.
[0013] Figure 1 A diagram illustrating a method for determining the hydroxyl coverage of the surface of cellulose achieved by a coating material.
[0014] The cellulose-based material of the present invention comprises: cellulose with a crystallinity of 50% or less; and a coating material that coats the hydroxyl groups on the surface of the cellulose, wherein the coating material is at least one selected from aliphatic compounds, aromatic compounds and higher alcohols, and the coating rate of the hydroxyl groups on the surface of the cellulose achieved by the coating material is 0.1% or more and 20% or less.
[0015] This configuration provides a cellulose-based material that balances the reactivity and aggregation inhibition of cellulose. More specifically, by sufficiently reducing the crystallinity of cellulose, reactivity can be improved, and by coating the hydroxyl groups on the surface of cellulose with a predetermined coating material in a predetermined proportion, aggregation of cellulose can be sufficiently suppressed while maintaining its reactivity.
[0016] On the other hand, if the aforementioned conditions are not met, satisfactory results cannot be obtained.
[0017] For example, when the crystallinity of cellulose is too high, even if it is coated with a specific coating material as described above, the reactivity cannot be adequately improved.
[0018] Furthermore, if the hydroxyl groups on the surface of cellulose are not coated with the specific coating material described above, even if the crystallinity conditions are met, the proportion of hydroxyl groups exposed on the surface will increase, thereby inducing hydrogen bonds between the hydroxyl groups. As a result, cellulose becomes more prone to aggregation. Therefore, even in liquids, the dispersibility of cellulose is significantly lower, and thus its reactivity decreases.
[0019] Furthermore, even if the crystallinity conditions described above are met, and the hydroxyl groups on the surface of cellulose are coated using the specific coating material described above, if the coating rate is too low, the effects of coating with the specific coating material described above cannot be fully obtained. As a result, the proportion of hydroxyl groups exposed on the surface of cellulose increases, hydrogen bonds between hydroxyl groups are induced, and cellulose becomes more prone to aggregation. Consequently, even in liquids, the dispersibility of cellulose is significantly lower, and thus the reactivity of cellulose decreases.
[0020] Furthermore, even if the crystallinity conditions described above are met, and the hydroxyl groups on the surface of cellulose are coated with the specific coating material described above, if the coating rate is too high, fewer hydroxyl groups will be exposed on the surface and be able to react, thereby eliminating the effect of reducing crystallinity.
[0021] Furthermore, the crystallinity of cellulose can be determined using X-ray crystal structure analysis (XRD). XRD can be performed, for example, using a single-crystal X-ray structure analysis apparatus such as the X'Pert PRO MPD manufactured by Malvern Panalytical.
[0022] Furthermore, in this invention, the hydroxyl group coating rate of the cellulose surface can be determined using pulsed NMR measurement as a polarity evaluation method and BET surface area measurement as a gas adsorption method. More specifically, as Figure 1 As shown.
[0023] First, standard samples without coating by a coating material were subjected to micronization under different conditions to obtain multiple samples with varying BET specific surface areas. Polarity of these samples was evaluated using pulsed NMR, and a graph was created with the vertical axis set to the polarity evaluation value obtained by pulsed NMR and the horizontal axis set to the BET specific surface area. A calibration curve was then plotted.
[0024] Next, for the sample being measured—that is, the sample in which the hydroxyl groups on the surface of cellulose have been coated with a coating material—the BET specific surface area and the polarity evaluation value obtained by pulse NMR are calculated, and point A is plotted on the graph. Then, the polarity evaluation value of this sample is compared with the polarity evaluation value at point B on a calibration curve having the same BET specific surface area as the sample, to determine the rate of reduction of the polarity evaluation value from point B. More specifically, for example, since the ratio of the polarity evaluation value at point A to the polarity evaluation value at point B is 0.90, the polarity evaluation value decreases by 10%, therefore it is determined that the hydroxyl group coating rate of the cellulose surface achieved by the coating material is 10%. Furthermore, for example, since the ratio of the polarity evaluation value at point A to the polarity evaluation value at point B is 0.10, the polarity evaluation value decreases by 90%, therefore it is determined that the hydroxyl group coating rate of the cellulose surface achieved by the coating material is 90%.
[0025] The crystallinity and the hydroxyl coverage of the cellulose surface achieved by the coating material described in the embodiments below are also values obtained in the manner described above.
[0026] [1-1] Cellulose The cellulose-based material of the present invention contains cellulose.
[0027] Cellulose is the main component of the cellulose-based material of this invention.
[0028] The cellulose content in the cellulose-based material is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more.
[0029] Cellulose-based materials can contain either natural or regenerated cellulose. Furthermore, cellulose-based materials can also contain both.
[0030] Cellulose-based materials can contain cellulose with either a type I or a type II crystal structure. Furthermore, cellulose-based materials can also contain both types of cellulose.
[0031] If reactivity is taken into consideration, the crystallinity of cellulose contained in the cellulose-based material only needs to be less than 50%, but preferably less than 25%, and more preferably less than 20%.
[0032] Therefore, the effects brought about by the present invention will be more significantly realized.
[0033] [1-2] Specific coating material As a coating material for coating the hydroxyl groups on the surface of the cellulose described above, the cellulose-based material contains at least one selected from the group consisting of aliphatic compounds, aromatic compounds and higher alcohols.
[0034] In the following description, such a coating material will also be referred to as a "specific coating material".
[0035] Aliphatic compounds used as specific coating materials only need to have aliphatic hydrocarbon groups within their molecules and not aromatic functional groups.
[0036] Aliphatic compounds include, for example, aliphatic hydrocarbons or various compounds having aliphatic hydrocarbon groups; more specifically, alcohols, carboxylic acids, amines, esters, ethers, amides, phosphate esters, etc. It is assumed that these compounds contain salts.
[0037] The number of carbon atoms in the aliphatic hydrocarbon and the aliphatic hydrocarbon group is not particularly limited, but is preferably 4 or more and 30 or less, more preferably 8 or more and 26 or less, and even more preferably 12 or more and 22 or less.
[0038] Therefore, it is possible to more appropriately coat the hydroxyl groups on the surface of cellulose with a smaller amount of specific coating material. As a result, when using cellulose-based materials as raw materials for chemical reactions with cellulose as the reaction substrate, the content of the specific coating material, which can be considered an impurity, can be further reduced, thus allowing the desired chemical reaction to proceed more appropriately. In particular, when the desired chemical reaction is an esterification reaction, the negative impact of the specific coating material on the esterification reaction can be effectively prevented. Furthermore, post-processing such as purification after the desired chemical reaction can be performed more appropriately.
[0039] Aromatic compounds used as specific coating materials only need to have aromatic functional groups within their molecules, and may further have aliphatic hydrocarbon groups, or they may not have aliphatic hydrocarbon groups.
[0040] Aromatic compounds include, for example, aromatic hydrocarbons, aromatic heterocyclic compounds, and various compounds having aromatic hydrocarbon groups or aromatic heterocycles. More specifically, they include alcohols, carboxylic acids, amines, esters, ethers, amides, phosphate esters, etc. It is assumed that these compounds contain salts.
[0041] The number of carbon atoms in the aromatic hydrocarbon and the aromatic hydrocarbon group is not particularly limited, but is preferably 6 or more and 26 or less, more preferably 10 or more and 22 or less, and even more preferably 13 or more and 18 or less.
[0042] Therefore, it is possible to more appropriately coat the hydroxyl groups on the surface of cellulose with a smaller amount of specific coating material. As a result, when using cellulose-based materials as raw materials for chemical reactions with cellulose as the reaction substrate, the content of the specific coating material, which can be considered an impurity, can be further reduced, thus allowing the desired chemical reaction to proceed more appropriately. In particular, when the desired chemical reaction is an esterification reaction, the negative impact of the specific coating material on the esterification reaction can be effectively prevented. Furthermore, post-processing such as purification after the desired chemical reaction can be performed more appropriately.
[0043] The higher alcohol used as a specific coating material only needs to be an alcohol compound containing 12 or more carbon atoms in its molecule. For example, it can also be an aliphatic compound or an aromatic compound.
[0044] In particular, the higher alcohol preferably has an aliphatic hydrocarbon group, more preferably has an aliphatic hydrocarbon group with 12 or more and 20 or less carbon atoms, and even more preferably has an aliphatic hydrocarbon group with 12 or more and 16 or less carbon atoms.
[0045] Therefore, it is possible to more appropriately coat the hydroxyl groups on the surface of cellulose with a smaller amount of specific coating material. As a result, when using cellulose-based materials as raw materials for chemical reactions with cellulose as the reaction substrate, the content of the specific coating material, which can be considered an impurity, can be further reduced, thus allowing the desired chemical reaction to proceed more appropriately. In particular, when the desired chemical reaction is an esterification reaction, the negative impact of the specific coating material on the esterification reaction can be effectively prevented. Furthermore, post-processing such as purification after the desired chemical reaction can be performed more appropriately.
[0046] Higher alcohols preferably do not have functional groups other than hydrocarbon groups and hydroxyl groups.
[0047] Therefore, when using cellulose-based materials as raw materials for chemical reactions with cellulose as the reaction substrate, the desired chemical reaction can be carried out appropriately. In particular, when the desired chemical reaction is an esterification reaction, the negative impact of a specific coating material on the esterification reaction can be effectively prevented. Furthermore, post-processing such as purification after the desired chemical reaction can also be appropriately carried out.
[0048] The specific coating material preferably contains an aliphatic compound, and more preferably a phosphate compound.
[0049] Therefore, it is possible to further and appropriately coat the hydroxyl groups on the surface of cellulose using a further small amount of a specific coating material. As a result, when using cellulose-based materials as raw materials for chemical reactions with cellulose as the reaction substrate, the content of the specific coating material, which is an impurity, can be further reduced, thus allowing the desired chemical reaction to proceed more appropriately. In particular, when the desired chemical reaction is an esterification reaction, the negative impact of the specific coating material on the esterification reaction can be effectively prevented. Furthermore, post-treatment processes such as purification after the desired chemical reaction can also be further and appropriately implemented.
[0050] In the case where a phosphate ester compound, which is an aliphatic compound, is contained, the coating rate of hydroxyl groups on the surface of cellulose achieved by the phosphate ester compound, which is an aliphatic compound, is preferably 0.1% or more and 20% or less.
[0051] Phosphate compounds are preferably represented by the following formula (1).
[0052] Chemical Formula 1
[0053] (In equation (1), m is 1 or 2, and n is an integer greater than 12 and less than 20.) Therefore, the effects described above will be more significantly enhanced.
[0054] When the cellulose-based material contains a phosphate ester compound represented by the above formula (1), the cellulose-based material preferably contains a compound in which n in the above formula (1) is 14 or more and 20 or less, and more preferably contains oleic acid phosphate, that is, a compound in which n in the above formula (1) is 18 or less.
[0055] Therefore, the effects described above will be more significantly enhanced.
[0056] In the case where oleate phosphate is contained as a phosphate compound, the coating rate of hydroxyl groups on the surface of cellulose achieved by oleate phosphate as a phosphate compound is preferably 0.1% or more and 20% or less.
[0057] As a specific coating material, the cellulose-based material may contain materials other than the phosphate ester compound, but the proportion of the phosphate ester compound in the total specific coating material contained in the cellulose-based material is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 90% by mass or more.
[0058] This will further amplify the effects described above.
[0059] The hydroxyl coverage of the cellulose surface achieved by the specific coating material only needs to be 0.1% or more and 20% or less, but preferably 0.1% or more and 17% or less.
[0060] Therefore, the effects brought about by the present invention will be more significantly realized.
[0061] The content of the specific coating material in the cellulose-based material is preferably 0.0001% by mass or more and 10% by mass or less, more preferably 0.0005% by mass or more and 2.0% by mass or less, and even more preferably 0.001% by mass or more and 1.0% by mass or less.
[0062] Therefore, it is easy to adjust the coating rate of the hydroxyl groups on the surface of cellulose, achieved by the specific coating material, to the range described above. Furthermore, since the amount of the specific coating material contained in the cellulose-based material that does not contribute to the coating of the hydroxyl groups on the surface of cellulose can be reduced, the content of the specific coating material as an impurity can be further reduced when using the cellulose-based material as a raw material for a chemical reaction with cellulose as the reaction substrate. Therefore, the desired chemical reaction can be carried out more appropriately. In particular, when the desired chemical reaction is an esterification reaction, the negative impact of the specific coating material on the esterification reaction can be effectively prevented. Furthermore, post-processing such as purification after the desired chemical reaction can be carried out more appropriately.
[0063] [1-3] Other ingredients The cellulose-based material of the present invention may also contain components other than the cellulose described above and the specific coating material. Hereinafter, such components will be referred to as "other components" within this scope.
[0064] Other components include, for example, hemicellulose, lignin, various cellulose derivatives, colorants, fillers, sizing agents, paper strength enhancers, flame retardants, antioxidants, insect repellents, mildew inhibitors, antibacterial agents, antistatic agents, flame retardant additives, ultraviolet absorbers, agglomeration inhibitors, release agents, processing aids, anti-drip agents, resin materials, plasticizers, and coating materials other than the specific coating materials described above.
[0065] The content of other components in the cellulose-based material of the present invention is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass or less.
[0066] [1-4] Applications of Cellulose-based Materials The cellulose-based material of the present invention can be used for any purpose. For example, it is preferred to use cellulose, which is the main component, as a raw material for cellulose ethers, and as an industrial raw material for pharmaceuticals, cosmetics, food, biomass materials, etc., and as a raw material for various chemical reactions.
[0067] Thus, although a higher level of reactivity and aggregation inhibition of cellulose is required when using it as a raw material for various chemical reactions, this requirement can be met according to the present invention. In other words, the effects of the present invention are more pronounced when cellulose-based materials are used as raw materials for various chemical reactions.
[0068] In addition, the cellulose-based material of the present invention can also be used for purposes other than those described above, such as materials for molded articles.
[0069] [2] Manufacturing method of cellulose-based materials Next, the method for manufacturing the cellulose-based material of the present invention will be described.
[0070] The cellulose-based material of the present invention can be manufactured, for example, by mixing various components such as a cellulose-containing material and a specific coating material. In this case, the timing of mixing the various components can be the same or different.
[0071] As a material containing cellulose, it can be made from materials such as pulp, waste paper, and waste clothing.
[0072] When mixing the various components, it is preferable to simultaneously perform micronization of the cellulose-containing material. Such a process can be appropriately carried out, for example, by using a dry bead mill.
[0073] In addition, during the aforementioned treatment, a dispersion medium that disperses cellulose-containing materials can also be used.
[0074] Such dispersion media can also be removed by centrifugation, filtration or gasification after the treatment described above.
[0075] Although preferred embodiments of the present invention have been described above, the present invention is not limited thereto.
[0076] For example, the cellulose-based materials of the present invention are not limited to materials manufactured using the methods described above.
[0077] Example Next, specific embodiments of the present invention will be described.
[0078] [3] Manufacturing of cellulose-based materials Example 1 Commercially available pulp (manufactured by CMPC Corporation, Guaiba BEKP) containing cellulose was prepared, oleic acid phosphate esters as a specific coating material were added to it, and a treatment was performed by a dry bead mill to mix them and refine the pulp.
[0079] The cellulose-based material obtained by the method described above contains cellulose with a crystallinity of 20% and oleate phosphate as a specific coating material for coating the hydroxyl groups on the surface of cellulose at a coating rate of 0.10%. The obtained cellulose-based material contains 99% cellulose by mass and 1% cellulose by mass for the specific coating material.
[0080] Examples 2 to 9 In addition to adjusting the type and amount of cellulose-containing raw materials, the type and amount of specific coating materials, and the processing conditions in the dry bead mill to make it... Figure 2 Aside from the configuration shown, cellulose-based materials are manufactured in the same manner as in Example 1.
[0081] In the cellulose-based materials of the various embodiments, the cellulose content is 95% by mass or more, and the content of the specific coating material is 0.001% by mass or more and 1.0% by mass or less.
[0082] Comparative Examples 1 to 5 In addition to adjusting the type and amount of cellulose-containing raw materials, the type and amount of specific coating materials, and the processing conditions in the dry bead mill to make it... Figure 2 Aside from the configuration shown, cellulose-based materials are manufactured in the same manner as in Example 1.
[0083] [4] Evaluation The cellulose-based materials involved in the various embodiments and comparative examples were evaluated as follows.
[0084] [4-1] Chemical reactivity The cellulose-based materials of the various embodiments and comparative examples were subjected to esterification reactions in the manner described below, and the chemical reactivity was evaluated.
[0085] First, 1.9 g of cellulose-based material, 25 mL of N-methyl-2-pyrrolidone, and 3 mL of pyridine were mixed and stirred at 90 °C to carry out an esterification reaction.
[0086] A portion of the reaction solution was collected at each predetermined time point from the start of the reaction, and the degree of substitution of the hydroxyl groups (DS value) was calculated. The DS value represents the proportion of the three hydroxyl groups present in a glucose unit constituting cellulose that have transformed into esters through the reaction, and is the average value of the entire cellulose molecule. Theoretically, the DS value is 0 (minimum) if all the hydroxyl groups of cellulose remain unreacted, and 3 (maximum) if all the hydroxyl groups of cellulose have reacted and become other groups. In other words, the higher the DS value, the greater the extent of esterification.
[0087] For each of the embodiments and comparative examples, the reaction was carried out from the start of the reaction until 4 hours, thereby confirming the shift in DS value.
[0088] The highest DS value obtained at each time point for each embodiment and each comparative example is set as the reaction rate of 100%. For other embodiments and comparative examples, the respective reaction rates are obtained according to the ratio of the embodiment with a reaction rate of 100%.
[0089] [4-2] Deagglomeration and dispersibility For the cellulose-based materials of the various embodiments and comparative examples, the deagglomeration and dispersibility were evaluated in the following manner.
[0090] Specifically, a cellulose dispersion was prepared by mixing cellulose-based materials with water to achieve a cellulose concentration of 0.5% by mass. The zeta potential was measured at 20°C using an Otsuka Electronics Zeta potentiometer (ELSZ-1000). It can be said that the higher the zeta potential value, the better the deagglomeration and dispersibility.
[0091] These results, together with the composition of the cellulose-based materials of the various embodiments and comparative examples, Figure 2 The summary is presented in the middle.
[0092] Depend on Figure 2 It is evident that excellent results were obtained in the aforementioned embodiments. In contrast, satisfactory results were not obtained in the aforementioned comparative examples.
[0093] Furthermore, the cellulose-based materials of each embodiment and comparative example were mixed with pure water at a content of 0.5% by mass, and after stirring for 10 minutes, the dispersions were allowed to stand, and the time until precipitation occurred was measured. The results showed that in the cellulose-based materials with a Zeta potential less than 20 mV, precipitation occurred within 15 seconds after standing. In contrast, in the cellulose-based materials with a Zeta potential greater than 20 mV, the dispersions remained clearly turbid and maintained their dispersed state even after standing for more than 15 seconds.
Claims
1. A cellulose-based material comprising: Cellulose, with a crystallinity of less than 50%; A coating material that coats the hydroxyl groups on the surface of the cellulose. The coating material is at least one selected from aliphatic compounds, aromatic compounds, and higher alcohols. The coating material achieves a coating rate of 0.1% or more and less than 20% of the hydroxyl groups on the surface of the cellulose.
2. The cellulose-based material as described in claim 1, wherein, The crystallinity of the cellulose is less than 25%.
3. The cellulose-based material as described in claim 1 or 2, wherein, The hydroxyl group coverage of the surface of the cellulose, which is achieved by the phosphate ester compound that is the aliphatic compound, is 0.1% or more and 20% or less.
4. The cellulose-based material as described in claim 3, wherein, The hydroxyl group coverage of the surface of the cellulose, achieved by oleic acid phosphate as the phosphate ester compound, is 0.1% or more and 20% or less.