Process for producing crosslinked cellulose ether

Abstract

To provide a process for producing a crosslinked cellulose ether that can be implemented on an industrial plant scale with a higher efficiency than conventional processes.SOLUTION: There is provided a process for producing a crosslinked cellulose ether including the steps of: (a) contacting at least one cellulose material with at least one alkalization reagent to form an activated cellulose material; (b) contacting the activated cellulose material of step (a) with at least one etherification reagent to form an uncrosslinked cellulose ether; (c) subjecting the cellulose ether of step (b) to a simultaneous or stepwise washing and / or granulating step; (d) adding at least one crosslinking agent to the uncrosslinked cellulose ether during the washing and / or granulating of step (c) to form a crosslinked cellulose ether; and (e) any other optional components desired.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a process for producing crosslinked cellulose ethers and to such a process. This relates to crosslinked cellulose ethers prepared by Seth. [Background technology]

[0002] Cellulose derivatives such as cellulose ethers are known for their excellent properties and physiological safety. For example, thickeners, adhesives, binders and dispersants, water retention agents, protective colloids, It is widely used as a fixing agent, as well as a suspending agent, emulsifier and film former. Cellulose ethers are used in various construction applications to improve the rheology of mortars. It is known to be used in dry mix mortar for concrete. The mortar is coated with a mortar-like material to impart water retention that limits water loss from the mortar to the absorbent substrate. This allows the hydraulic binder (cement or gypsum) to fully harden during the setting reaction. This allows for the availability of water, resulting in high mechanical strength of the final product. This results in incomplete curing, poor mechanical strength, crack formation, and reduced abrasion resistance.

[0003] To date, cellulose ethers have been produced by converting cellulose starting materials such as cellulose pulp into There are two process operations (steps or stages): (1) an alkalinization operation and (2) an etherification operation. Cellulose has been produced by well-known conventional processes, including subjecting it to a polymerization operation. Well-known state-of-the-art conventional procedures for making ethers are described, for example, in U.S. Pat. The conventional process is shown and described in US Pat. No. 5,893 B1. (2) alkalizing the cellulose pulp; and (3) etherifying the alkalized cellulose pulp. For example, in a conventional process, cellulose The rose pulp is alkalized with sodium hydroxide and mixed with methyl chloride and alkylene oxide. It is etherified with ethylene oxide or propylene oxide. Each of the alkalinization and etherification operations is carried out stepwise, i.e., one step at a time. The process may be carried out in one or two or more different separate steps, each step being carried out at different pressures. The process can be carried out for a predetermined period of time under specific process conditions of temperature and temperature. (c) washing the cellulose ether after the cellulose ether is prepared; (d) drying the cellulose ether; and (e) forming the cellulose ether into particles. The resulting mixture can then be subjected to further desired process steps, such as milling into a powder. In the present invention, the alkalinization and etherification operations can be carried out in a single reactor or in two or more reactors. It is possible.

[0004] More recently, crosslinking techniques have been used to create crosslinked cellulose ethers. This provides an improvement over conventional processes for making cellulose ethers. Bridge techniques include the use of methylene dichloride, epichlorohydrin, or various diglycidyl ethers. Cellulose ethers that can be chain extended or crosslinked using bifunctional crosslinkers such as For example, U.S. Patent No. 6,958,393 B2 (corresponding to EP 1384727 B9) ) uses crosslinking techniques to create polyether groups containing crosslinked cellulose ethers. The crosslinked cellulose ether is prepared by subjecting the cellulose ether to a temperature of 90 degrees Celsius (°C). ) or less, inert atmosphere, e.g. nitrogen (N2), presence of polyether groups containing crosslinkers It is prepared by crosslinking in the presence of alkali or caustic. The crosslinking of the cellulose ethers occurs in the reactor in which the cellulose ethers themselves are made and in the presence of caustic It occurs in the presence of alkali or alkali.

[0005] In contrast to pure non-crosslinked cellulose ethers, e.g. in dry mix mortar formulations One advantage of using crosslinked cellulose ethers in the composition is that the cellulose ether By crosslinking with a crosslinking agent, the viscosity of an aqueous solution of cellulose ether can be increased. The resulting crosslinked cellulose ether having increased or high viscosity can still be They can remain soluble in aqueous solutions. They can also be produced using crosslinking techniques to increase the water solubility of the polymers. Crosslinked cellulose ethers with high viscosity, for example, are used in mortar applications. and can be used at reduced dosage levels without compromising performance in the application. Cellulose ethers are relatively expensive components used in mortar formulations and are Reducing the cellulose ether dosage in the formulation can save on formulation costs. do.

[0006] In known processes, the dosage of crosslinking agent used to crosslink the cellulose ether is kept very low to prevent "over-crosslinking" and then remains water insoluble and and provide a polymer product that does not contribute to the viscosity of the aqueous solution. Uniform distribution of the small amount of crosslinking agent added to the vessel contents is achieved using known processes. It is very difficult to achieve this.

[0007] "Over-crosslinking" as used herein refers to crosslinking of cellulose ethers. The reaction between the ether and the crosslinker is so extensive that it forms a three-dimensional network of covalently bonded cellulose ether chains. This means that such chains are not water-soluble and form gel particles in the aqueous phase. Excessive crosslinking leads to a decrease in the water solubility of the cellulose ether in aqueous solution. If over-crosslinking occurs with cellulose ether, the amount of crosslinked cellulose ether obtained will decrease. The crosslinked cellulose ether becomes soluble in the aqueous solution, and the appropriate viscosity of the crosslinked cellulose ether is achieved in the aqueous solution. In other words, excessive crosslinking leads to an undesirable decrease in viscosity. Crosslinked cellulose ethers exhibit reduced water solubility compared to non-crosslinked cellulose ethers. The degree of crosslinking that results is indicated.

[0008] For example, the crosslinked cellulose ethers described in U.S. Pat. No. 6,958,393 B2 Known processes for crosslinking cellulose include (1) suspending cellulose in an alkali metal solubility medium; (2) alkalizing the cellulose with one or more alkyl groups; (3) reacting the alkalized cellulose with halogen oxide present in the suspension medium; (4) subsequently or simultaneously, reacting the alkalized cellulose with a specific amount of alkyl ester; (5) reacting the crosslinker with an alkali metal hydroxide and / or or an alkalizing agent is added to the reaction mixture of step (4); (6) the resulting crosslinked cell is The process includes several steps, such as purifying and drying the rose ether.

[0009] The process described in U.S. Patent No. 6,958,393 B2 involves (1) a pressurized water bath at high pressure; (2) the addition of an epitaxial crosslinker during the etherification step of the process; (3) Use of chlorohydrins (ECH), either pure or at low levels dispersed in organic solvents (4) uniform distribution of crosslinker with limited low levels of pure crosslinker; Beauty

[0010] (5) The product obtained as a result of the process must exhibit good performance. In addition to the above requirements, the use of the above known processes may, in some cases, This can result in poor distribution of the crosslinker, resulting in overcrosslinking and undesirable viscosity of the crosslinked cellulose product. Also, the efficiency of the known process of U.S. Pat. No. 6,958,393 B2 was reduced. The rate is scaled from laboratory scale to pilot plant scale and / or ultimately to full scale industrial scale. The above known processes are not easily transferred to plant scale. To operate under simulated and known process conditions requires greater expertise, knowledge and skill. A concerted effort is needed.

[0011] For the crosslinking process to be successful, the crosslinking agent must be introduced into the process in small amounts to achieve crosslinking. It has been found necessary to achieve a uniform distribution of the crosslinking agent. To achieve this, we aimed to create the desired branched polymer and prevent localized overdosing that could lead to overcrosslinking. Over-crosslinking (i.e., high levels of crosslinking) can lead to localized crosslink networks. Overcrosslinking leads to increased levels of crosslinked cellulose esters and localized insoluble material. When and at what stage, step or operation of the ether manufacturing process is the crosslinker introduced into the process? For example, the crosslinking agent may be added before or after the etherification step. However, alkalization and acetification may be introduced or added during or after the The tertiary reaction is exothermic and therefore affects whether overcrosslinking occurs in the process. There are many factors that can cause this. These factors include, for example, reaction time, The type of crosslinker used, the amount of crosslinker introduced into the process, and the way in which the crosslinker is introduced into the process. The process, the process conditions at the time the crosslinker is introduced, and how long the crosslinker is present in the process. The technology may be introduced or included in the system. Summary of the Invention [Problem to be solved by the invention]

[0012] Thus, it can be used and produced with higher efficiency than known conventional processes. A novel method for producing crosslinked cellulose ethers that can be implemented on an industrial plant scale It is desirable to provide an improved process, and at the same time, The performance of the resulting product is equal to or better than that of known conventional processes. Remains good.

[0013] The problems of the prior art processes can be solved using the process of the present invention. The present invention relates to a crosslinked cellulose ether (herein "XCE") having an appropriately increased viscosity. The present invention is directed to a novel process for preparing

[0014] The present invention relates to a novel low pressure (e.g., The present invention is directed to a process for producing cellulose ethers at atmospheric pressure. This enables the production of XCEs such as hydroxyethyl methylcellulose derivatives in a single process. It provides for crosslinking agent administration, which avoids the costly high pressure injection process known in the art. Not only does this eliminate a step, but it also provides an XCE product with increased viscosity in aqueous solution. Such XCE products can be used at reduced levels, for example in dry mix mortar formulations. can be used and still provide adequate performance characteristics.

[0015] In one embodiment, administration of a cross-linking agent is performed in the process of the invention, e.g., after washing and / or or during the granulation step of the process, these steps This is a step carried out after and downstream of the high pressure etherification process step. In the present invention, controlling the dosage of crosslinker leads to better rheological performance (higher viscosity level). and providing an economical method for producing XCE products with less technical effort. The administration concept of the present invention also simplifies the process for adding the crosslinking agent compared to known processes. It has the further advantage of an enhanced process window.

[0016] In one preferred embodiment, the present invention provides a method for producing a medicament for the treatment of a cancer, comprising: (a) contacting at least one cellulosic material with at least one alkalizing agent; The activated cellulose material is then heated to a pressure of, for example, 500 kilopascals (kPa) or less (≦). The activated cellulose material is formed by heating the activated cellulose material at a temperature of, for example, 50° C. or less (≦). forming a (b) reacting the activated cellulose material of step (a) with at least one etherification reagent; contacting to form a non-crosslinked cellulose ether; (c) reacting the non-crosslinked cellulose ether of step (b) with (ci) a washing step and a granulation step, the washing step being carried out simultaneously; a mixing and granulation step, or (cii) a washing step and a granulation step, wherein the washing step is The washing and granulation steps are separate steps in a stepwise procedure. A washing step and a granulation step are carried out, or (ciii) a wash step only; or (civ) a granulation step only; , (d) at least one crosslinking agent and a non-crosslinked cellulose ether are combined to form a crosslinked cellulose ether At least one crosslinking agent is added to the non-crosslinked cellulose ether to form a cellulose ether. wherein the cross-linking agent is (di) during the washing step (ci) and during the granulation step (ci), or (dii) during the washing step (cii) and during the granulation step (cii), or , (diii) only during the washing step (cii), or (div) only during the granulation step (cii), or (dv) during the washing step (ciii), or (dvi) The step of adding, which is added to the process during the granulation step (civ) The present invention relates to a process for manufacturing XCE, including:

[0017] In an optional preferred embodiment, the XCE from step (d) is The mixture is subjected to one or more steps selected from a grinding step, a drying step, and a milling step. It is possible.

[0018] In another embodiment, the present invention is directed to the XCE produced by the above process. do.

[0019] Yet another embodiment of the present invention relates to a mortar-forming composition comprising the XCE described above.

[0020] Surprisingly, the cellulose during the washing step and / or the granulation step at atmospheric pressure The addition of crosslinkers to ethers allows for a wide processing window of crosslinkers at dosage levels ranging from The results are significantly more uniform and independent of the aqueous solution of the cellulose ether. It was found that this resulted in a more robust viscosity increase than previously known processes. This contrasts with the addition of crosslinker during the etherification step at higher pressures, which was previously required in the previous study. It is.

[0021] Some other advantages of the process of the present invention include, for example, (1) control of the dosage of the crosslinker. This is an advantageous, desired (and appropriate) step to avoid over-crosslinking, especially during use of large-scale plant processes. (2) the process results in an XCE with an increased viscosity level (as required); (3) The process is small and does not require special high-pressure equipment. (4) the small amount of crosslinking agent required in large plant-scale processes; (5) the process is capable of uniform distribution of the crosslinking agent; Advantages of the present invention include that no additional spray devices are required in the reactor used for the purpose.

[0022] Moreover, the process of the present invention advantageously comprises the steps of: In addition, the present invention advantageously provides an XCE product having the same or better performance characteristics as the previously described product. The process of the present invention may be carried out in the washing step and / or the granulation step of the process of the present invention. Can be carried out on a large plant scale with the crosslinker dosages required and without problems of overcrosslinking It can be carried out. [Brief description of the drawings]

[0023] The process of the present invention is illustrated by, but is limited by, the following figures: In the drawings, the same reference numbers are used to refer to like elements in the various figures. [Figure 1] FIG. 1 is a schematic flow diagram illustrating one process of the present invention. [Diagram 2] FIG. 2 is a schematic flow diagram illustrating another embodiment of the process of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] In this disclosure, "uniform distribution" refers to contacting the cellulose fibers with different components. In this specification, the cellulose fibers and other components are considered to be the smallest mass of all the masses of a given volume. The smallest volume element is the one that has the same distribution in the product elements. It is cubic with an edge length 10 times the average particle size of the cellulose fibers.

[0025] Generally, the process for producing XCE includes an alkalinization step and an etherification step. The step of milling the cellulose starting material may be carried out. It is preferable to do this before the alkalinization step, and the XCE cleaning (e.g., hot water (H2 O), granulation, drying, and / or grinding steps can be carried out, typically Preferably after the etherification step. In the process of the present invention, the crosslinker is Introduced or added to the washing operation, the granulation operation, or both the washing and granulation operations, Contacting the cellulose ether to provide crosslinking of the uncrosslinked cellulose ether.

[0026] In one broad embodiment, the present invention relates to a process for producing an XCE product. Regarding the dosage and addition of the crosslinking agent, in one preferred embodiment, the crosslinking agent is It is added to the process wash operation, which is a later operation downstream of the etherification step of the process. In another preferred embodiment, the cross-linking agent is added or administered to the process. is added to the pelletizing operation of the process, which is a later operation downstream of the etherification step of In yet another preferred embodiment, the cross-linking agent is administered to or into the process. It is added or administered to both the washing and granulation operations. For example, a cross-linking agent is added to the granulation In embodiments where the first portion of the crosslinking agent is added to both the washing and granulation operations of the process, A portion of the cross-linking agent can be added in the washing step and a second portion of the cross-linking agent can be added in the granulation step. This can be done.

[0027] The dosage of the crosslinking agent used in the present invention is the same as that of products prepared by known processes. This results in ultra-high viscosity products with rheological performance (e.g., high viscosity levels). Advantageously, the process of the present invention provides a wider process window than conventional processes. provide.

[0028] The dosage of crosslinker used in the present invention depends on the process conditions at which the crosslinker is introduced into the process. The advantage of administering the crosslinking agent at a process point throughout the process of the present invention is that it is advantageous to As a result, it provides a uniform distribution of the crosslinking agent in the non-crosslinked cellulose ether. This objective can be achieved more easily compared to the conventional process. Therefore, the process of the present invention is different from the processes known in the art that use toxic crosslinking agents. Additionally, there are no safety issues or environmental concerns at the XCE manufacturing plant.

[0029] Further advantages of the process of the present invention include, for example, (1) the process is Easy to use based on diglycidyl ether chemistry such as 985 or Epilox P13-42 (2) the crosslinking agent must be non-toxic; and (3) the crosslinking agent must be , insoluble in water, or simply very poorly soluble in water. Known processes use epichlorohydrin (ECH) as a crosslinker system. Such known processes, for example, epichlorohydrin, are (1) known to be toxic; (2) it is carcinogenic, and (3) it has a low boiling point (116°C) / low molecular weight (Mw) 92.53 g mol -1 ) Table I shows a comparison of the physical data for Epilox crosslinker versus epichlorohydrin crosslinker. do. [Table 1]

[0030] The process of the present invention provides beneficial rheological behavior and advantageous properties in various application areas. The present invention provides a method for preparing an XCE ether, which is capable of irreversibly reacting with the XCE ether. As a crosslinking agent, a C10-C24 alkyl bifunctional compound (oxirane and / or halo The present invention uses polypropylene glycol diglycidyl ether. In the method, the cross-linking agent is introduced in the washing step and / or the granulation step of the process. Prior art processes for preparing XCE using ECH as a crosslinker result in the formation of insoluble And the crosslinkers useful in the present invention have less environmental concerns than ECH. do not have.

[0031] In one broad embodiment, the process of the invention for producing XCE comprises: (a) at least one contacting at least one cellulose material with at least one alkalizing agent to activate the cellulose material; forming an activated cellulose material such that the cellulose material is formed at low pressure; (b) contacting the activated cellulose material of step (a) with at least one etherification reagent; (c) contacting the non-crosslinked cellulose ether of step (b) with the non-crosslinked cellulose ether to form a non-crosslinked cellulose ether; subjecting the crosslinked cellulose ether to a washing step and / or a granulation step. and (d) at least one crosslinking agent and a non-crosslinked cellulose ether to form a crosslinked cellulose ether. During the washing step, during the granulation step or during the washing step to form a terephthalate. At least one crosslinking agent is added to the non-crosslinked cellulose ether during both the granulation step and the granulation step. Optionally, the XCE from step (d) above is further added to one or more of the steps of refining, drying, and milling the The step of

[0032] Referring to FIG. 1, one broad process of the present invention, generally designated by the reference numeral 10, Various general processes for producing XCEs with enhanced aqueous viscosity are presented. The process steps or operations shown are as follows: XCE produced using the process of the present invention For example, it can be used in mortar formulations. The process 10 for producing ethylenediaminetetraacetate includes, for example, an alkalinization step 13, an etherification step 15, a cleaning step 19 (typically a hot water wash) at the front end of the process Optional cellulose grinding step 21, optional granulation step 23, washing step 1 9 and / or any optional drying / grinding steps that may be performed after the granulation step 23. In one embodiment shown in FIG. Step 23 is carried out in stages, i.e., washing step 19 is carried out followed by granulation step 2. 3 is carried out in two separate steps.

[0033] FIG. 1 shows the alkalizing step as indicated by arrows 11a and 12a, respectively. Shown is a cellulosic starting material 11, such as pulp and an alkalizing reagent 12, which proceeds to step 13. The mixture of the cellulose starting material 11 and the alkalizing agent 12 is subjected to the alkalizing step. The general process as shown in FIG. Optional steps (or operations) such as the optional grinding step 21 previously described are shown in dotted lines. The cellulose starting material, such as a pulp sheet, can be milled to produce cellulose. The material 11 is ground into flocs, and then, as shown by the arrow 11a, an alkalizing step is performed. Continue with step 13.

[0034] Referring again to FIG. 1, the optional grinding step 21 shown in dotted lines in FIG. In this example, the cellulose material 11 is converted into In a preferred embodiment, a comminuted particulate cellulose material can be provided, which comprises: The comminuted cellulose material 11 in particulate form is alkalized as indicated by arrow 11a. Continue with step 13. The grinding step 21 is optional, but the grinding step 21 is typically Typically, the cellulosic starting material 11 (e.g., wood pulp) is ground and readily digested in a reactor. The result is a comminuted floc of cellulose that can flow and mix easily. The crushed flocs are also used in the preferred embodiment to allow for the removal of the flocs from the conventional spray degassing system. The cellulose flocs mixed in the reactor are alkalized using a device or means. Contact with the alkalizing reagent 12 is easily achieved, such as by spraying the reagent.

[0035] In the alkalinization step 13, an alkalinization reagent 1 such as NaOH (50% in water) 2 and the cellulose material 11 are mixed to, for example, add an alkalizing agent 12 to the cellulose. By using a spraying device or means to spray the base material 11, the base material 11 is brought into uniform contact with the base material 11. 3 to form activated cellulose 14, which is reacted with cellulose 20 at 40° C., as indicated by arrow 14 a. The alkalinization and etherification steps of the present invention can proceed to the etherification step 15. The tapping can be carried out in a single reactor or in two or more reactors. In one embodiment, the alkalinization and etherification steps of the present invention are carried out in one reactor.

[0036] After the alkalinization step 13, the activated cellulose 14 is shown by arrow 16a. The etherification step 15 is then treated with an etherification reagent 16 to obtain an etherification product. In the etherification step 15, an etherification reagent 16 is introduced into the etherification step 15. , contacting with activated cellulose 14 to form a non-crosslinked cellulose ether 17. During the polymerization step 15, the non-crosslinked cellulose ether 17 is formed at high pressure and temperature, and then Then, as shown by arrow 17a, the process proceeds to cleaning step 19 (hot water cleaning). The uncrosslinked cellulose ether 17 after the etherification step 15 typically has unwanted volatile It has by-products and salts (NaCl), therefore, in a preferred embodiment, etherification After step 15, the uncrosslinked cellulose ether 17 is , through the washing step 19, unwanted volatile by-products from the non-crosslinked cellulose ether 17 The mixture is washed to remove impurities, salts, and other impurities, followed by a granulation step 23, a drying step 24, and and / or proceed to milling step 24.

[0037] In the process of the present invention, the washing step can introduce the cross-linking agent into the process. (See step 19 of FIG. 1.) ), the granulation step is another step in the process of the present invention where a cross-linking agent can be introduced into the process. A place or location (see step 25 in Figure 2). A cross-linking agent or cross-linking agent 18 is added in a washing step 19, as indicated by arrow 18a. In the washing step 19, the non-crosslinked cellulose ether 17 and the crosslinking agent 18 are mixed together. The washing step 19 is a low-pressure, high-temperature operation. , which advantageously serves to allow for the addition of an appropriate, predetermined dose of cross-linking agent 18.

[0038] During the washing step 19, the uncrosslinked cellulose ether 17 is in intimate contact with the crosslinker 18. The mixture is then washed with hot water (e.g., >90° C.) during the washing step 19. ), the crosslinker 18 reacts with the non-crosslinked cellulose ether reactants to form non-crosslinked cellulose ethers. Cross-linking was performed on the glycerol ether 17 to form XCE22, as shown by arrow 19a. After the washing step 19, the warm water is removed by filtration and / or centrifugation (not shown). Water is removed from the XCE. Filter and / or centrifuge the wash water from the XCE product. This allows impurities and salts present in the wash water to remain in the wash water and be filtered and / or centrifuged. The "purified" X in the form of a wet filter cake remains with the wash water as a result of the centrifugation. After filtration, the wet filter cake of XCE22 is shown by arrow 22a. As shown, the process proceeds to the optional granulation step 23, which is shown as a dotted line in FIG. The washing and granulation step 23 is then performed to form a granulated material containing XCE. The XCE thus obtained is dried as indicated by the dotted line in FIG. and / or may proceed to an optional process step, such as grinding step 24. .

[0039] Referring now to FIG. 2, another broad process of the present invention is shown, generally designated by the reference numeral 20. and various general process operations or steps for producing the XCE of the present invention. Process 20 is shown, which is the addition of a crosslinking agent and thus the non-crosslinked cellulose acetate. The crosslinking reaction between the terpenes and the crosslinking agent occurs under slightly different process conditions in the granulation step 25 (used The same process steps or steps as shown in Figure 1 occur during For example, as shown in FIG. 2, the process 20 of the present invention is The cellulose ether 17 is prepared and is ready for the washing step 19 and the granulation step 25. The process described above with reference to FIG. 1 was repeated under the same process steps and process conditions. In the embodiment shown in FIG. It is added to the granulation step 25 as shown by 18a'.

[0040] During the washing step 19, the non-crosslinked cellulose ether 17 is washed with warm water (e.g., >90°C). The non-crosslinked cellulose is then removed by filtration and / or centrifugation (not shown). After washing step 19, the hot water can be removed from the cellulose ether. and potentially other impurities. By filtering and / or centrifuging the wash water, impurities and salts present in the wash water are removed. It remains in the purified water and with the wash water when filtered, moistening the "purified" non-crosslinked cellulose ether. After filtration, the uncrosslinked cellulose ether is provided in the form of a wet filter cake. The tar cake proceeds to a granulation step 25, as indicated by arrow 19a, where the granulated material After the washing step 19 and filtration, and during the granulation step 25, a cross-linking agent 18' is introduced or added to the granulation step 25 as indicated by arrow 18a'. Next, the washed non-crosslinked cellulose ether filter cake (indicated by arrow 19a) is As shown in FIG. 1, the washing step 19 and the cross-linking agent 18′ are mixed together and added to the granulation step. In step 25, the mixture is granulated.

[0041] The granulation operation 25 shown in FIG. 2 also uses a low pressure (e.g., 50 0 kPa [<] operation, which allows the addition of an appropriate, predetermined dose of crosslinking agent 18'. Also, the addition of the cross-linking agent 18' during the granulation step 25 is advantageous in one embodiment. In one embodiment, the reaction is carried out at a temperature of 65° C. to 100° C., and in another embodiment, at a temperature of 70° C. to 90° C. In the form, the granulated material is cooled, for example, to below 65° C. During the granulation step 25 , the uncrosslinked cellulose remains in intimate contact with the crosslinker 18' and is subjected to low pressure (e.g., <5 00 kPa) and elevated temperature (e.g., >70° C. in one embodiment). As 25 proceeds, the crosslinker 18' reacts with the washed, uncrosslinked cellulose ether reactant. In response, crosslinks are generated in the non-crosslinked cellulose ether 17. After the granulation operation 25, the arrow 25 As shown by a, the non-crosslinked cellulose ether was Next, the granulated XCE 26 is transformed into the granulated XCE 26 as shown by the arrow 26a in FIG. Optional steps such as drying step 27 and / or milling step 27 are shown in dotted lines in The user may proceed to the next process step of their choice.

[0042] As mentioned above, after the washing and granulation steps, the XCE product of the present invention is 2, as shown by the dotted lines in FIGS. 1 and 2, respectively. This can be carried on to one or more further optional operations or steps 24 and 27. For example, an optional step may be a further purification process to remove unwanted impurities. cess, a drying step to dry the granulated XCE, and / or a drying step to powder the XCE. A milling step for forming the product may be selected from steps known to those skilled in the art. Each of the above optional operations may be performed in a single step operation, and Optionally combine two or more of the above optional steps into a single operation. Steps 24 and 27 are optional in the process of the present invention. Typically, one or more of steps 24 and 27 will be desired and used. For example, in one preferred embodiment, the XCE product is As shown in FIG. 1, the drying / milling step 24 is shown in dotted line in FIG. 1 or 2. The produced XCE product can be passed on to further processing steps and / or storage. do.

[0043] The cellulose ether of the present invention is produced by the XCE production process. The starting material added to the potashing operation is cellulose. Cellulose pulp is typically is obtained, for example, from wood pulp or cotton linter pulp. The pulp is typically It is ground using conventional grinding means to provide the cellulose in powder or floc form. In one preferred embodiment, suitable cellulose starting materials useful in the present invention include comminuted cellulose. Other preferred pulp materials include ground wood pulp, ground linter pulp, and mixtures thereof. In a preferred embodiment, wood pulp is used in the process, the wood pulp being subjected to an alkalizing process. As a means of making the cellulose more fluid when added to the processing step, It is crushed into crushed flocs.

[0044] The cellulose material used in the alkalizing step of the process of the present invention may be Alkalizing agents that can be used include, for example, any of the above-mentioned known in the art. Alkaline reagents include sodium hydroxide ( NaOH), potassium hydroxide (KOH), lithium hydroxide (LiOH), and their In some embodiments, the mixture includes a solution of an alkali metal hydroxide, such as KOH. Alternatively, an alkaline aqueous solution of LiOH is suitable for use as an alkalizing agent, but For economic reasons, the alkali metal hydroxides used as alkalizing agents in the present invention are In a preferred embodiment, the alkali metal hydroxide used in the present invention is The compound was 50% caustic available from The Dow Chemical Company. Soda. The alkalizing agent is one preferred agent when carrying out the process of the present invention. In an embodiment, the method is used to alkalize natural cellulose or cellulose hydrate. do.

[0045] Generally, the alkalizing agent is in the form of an aqueous mixture of the alkalizing agent in water (e.g. The concentration of the aqueous solution can vary. For example, the aqueous solution is Based on the amount percent, in one embodiment, about 10 weight percent (wt%) to 90 wt% In another embodiment, the content is 25% by weight to 75% by weight, and in yet another embodiment, the content is 40% by weight to 60% by weight. In a preferred embodiment, the aqueous solution is 50% alkalizing agent in water and It is used as such.

[0046] As previously mentioned, the alkalizing agent may be, during the alkalizing step of the process, e.g. It is either incorporated into the process as an alkaline solution, more specifically 50% NaOH in water, or or will be introduced.

[0047] The alkalizing agent is used in the process of the present invention to alkalize or oxidize the cellulose starting material. or "activate" it to form an "activated cellulose ether material." At least one cellulosic material is contacted with an alkalizing agent, the alkalizing agent comprising a protease. The cellulose is alkalized under contact conditions to form an activated cellulose material. The cellulose can be prepared by known techniques, such as by spraying and mixing an alkalizing agent with the cellulose. This is carried out in stages.

[0048] The water used in the alkalinizing reagent may come from any source. Different types of water are Examples of alkalizing agents include tap water, drinking water, and deionized water. It is formed by mixing an alkalizing agent and water.

[0049] An alkalizing agent that is added during the alkalizing step to contact the cellulosic material The NaOH may be added by any known means, such as spraying and any method known in the art that allows for uniform distribution of the NaOH. The method may be carried out by other means known to those skilled in the art, and may be carried out to obtain sufficient activation of the cellulose pulp. Make sure.

[0050] The alkalinization step of the process is carried out under low pressure and low temperature conditions. The pressure in the calcination step is 100 kPa to 500 kPa in one embodiment, In another embodiment, the pressure is 150 kPa to 450 kPa, and in another embodiment, the pressure is 200 kPa to 400 kPa. The above pressure ranges are typical pressure levels in the reactor during the alkalinization step. This is the range.

[0051] Also, for example, the temperature of the alkalinization step of the process is in one embodiment 10° C. to 5° C. 0°C, in another embodiment from 15°C to 45°C, and in yet another embodiment from 20°C to 40°C The above temperature ranges are typical temperature ranges in the reactor during the alkalinization step. .

[0052] Generally, the etherification reagent is added to the etherification step of the process and the activated cell is The etherification reagent is mixed with the cellulose material so that the etherification reagent with the cellulose material forms a uniform reaction mixture. This then reacts under the process of etherification to form a cellulose ether. To produce a cellulose ether according to the process of the present invention, an etherification The reagent is mixed with the activated cellulose material prepared in the alkalization step above. Etherification reagents used to prepare cellulose ethers include, for example, those described in the art. The etherification reagents may include one or more of the etherification reagents known in the art. For example, the etherification reagents may include ethyl Ethylene oxide (EO), propylene oxide (PO), butylene oxide (BO), methyl chloride In one preferred embodiment, the solvent may include ethyl acetate, ethyl chloride, ethyl acetate, and mixtures thereof. Etherification agents useful in the present invention include, for example, methyl chloride, propylene oxide, ethylene oxide, and mixtures thereof.

[0053] The amount of etherification reagent added to the etherification operation of the XCE production process may be, for example, In one embodiment, the cellulose ether has 4 moles of ether per mole of anhydroglucose unit. In another embodiment, the alkoxylation agent (mol / AGU) is 4.5 mol / AGU~5.5mol / AGU

[0054] In yet another embodiment, the amount is between 4.7 mol / AGU and 5.3 mol / AGU. When the amount of etherification reagent used is <4 mol / AGU, the cellulose ether is The amount of etherification reagent used may be >6 mol / AGU, this high dosage of etherification reagent results in cellulose ethers It may become hydrophobic and reduce water solubility.

[0055] An etherification reagent added to the etherification step to contact the activated cellulose may be added by any known means, for example, using conventional equipment known in the art. This can be done by flowing the gas through the reactor.

[0056] The etherification step of the process can be carried out, for example, in a reaction vessel (reactor) under an inert atmosphere. The inert materials used in the process include, for example, N2, argon, and During the etherification step of the process and when the reaction of the reactants occurs, As the reaction proceeds to form the cellulose ether material, pressure increases as a result of the exothermic reaction. and the temperature increases.

[0057] Since cellulose ether products are formed during the etherification step, the esterification of the process The pressure in the etherification step is, for example, 1,500 kPa to 2,500 kPa in one embodiment. a, in another embodiment, 1,600 kPa to 2,400 kPa, and in yet another embodiment, 1 The range is 800kPa to 2,200kPa. At pressures below 1,500kPa, the reaction The response rate is too slow and at pressures above 2,500 kPa, special high pressure equipment is required.

[0058] The temperature of the etherification step of the process is, for example, 60° C. to 100° C. in one embodiment. In another embodiment, the temperature is 70°C to 90°C, and in yet another embodiment, the temperature is 75°C to 85°C. At temperatures below 0°C the reaction rate becomes unacceptably slow, and at temperatures above 100°C Unwanted side reactions may occur and the pressure may increase. For example, if the pressure is 3,000 kPa If the pressure rises above 100kV, a different, more expensive pressure reactor is required that can handle the high pressures. become.

[0059] In one preferred embodiment of the process, after the etherification step described above, non-crosslinked ceramide is Cross-linking of the cellulose ethers occurs during the washing / granulation stage of the process. The addition of the agent is easily accomplished at the low pressure conditions of the washing / granulation stage, so crosslinking is an integral part of the washing process. This is achieved by introducing a cross-linking agent into the granulation stage.

[0060] Generally, crosslinkers useful in the present invention comprise (i) at least one crosslinking agent; and (ii) a diluent. The mixture comprises a vehicle and (iii) any other optional ingredients as desired.

[0061] The crosslinking agents used to prepare the cellulose ethers of the present invention can be, for example, those known in the art. The crosslinking agent may include one or more crosslinking agents known in the art. However, in a preferred embodiment, the present invention Crosslinkers useful in the art are generally water insoluble crosslinkers or those with a solubility of less than 10 percent in water. In a preferred embodiment, the crosslinking agent is a process agent having less than 100% water. They are added to the gas to prevent, for example, hydrolysis and other undesirable side reactions from occurring. For this reason, it is desirable to use a crosslinking agent that is water-insoluble. With respect to water solubility, it has no water solubility or has low (weak or poor) water solubility of less than 10%. In other embodiments, the water solubility of the crosslinking agent is between 0% and less than 9% and 0 The water solubility of the crosslinker can be determined by thermographic analysis as known in the art. It can be measured by

[0062] For example, the water-insoluble nature of the crosslinking agent may result in the hydroxyl (-OH) groups of the cellulose backbone Optimization of desirable side reactions with ethylenediaminetetraacetate occurs, reducing the amount of water available for the washing and granulation steps. Undesirable side reactions with OH groups are minimized.

[0063] Crosslinking agents suitable for use in the present invention include, for example, polyoxyalkylenes or polyalkenyls. The alkylene glycol group and the cellulose ether when crosslinking the cellulose ether Two or more groups, such as halogen groups, glycidyl groups or epoxy groups, which form an ether bond, are preferably Preferably, the compound has two bridging groups or an ethylenically unsaturated group, such as a vinyl group. Suitable difunctional compounds include, for example, 1,2-dichloro(poly)alkoxy ethers. dichloropolyoxyethylene, diglycidyl polyalkoxy ether, diglycidyl divinyl phosphonates, divinyl polyoxyalkylenes containing sulfonic groups, and Mixtures of two different functional groups can also be used. Examples of compounds containing different functional groups include diglycidyl polyoxypropylene, glycidyl aryl(poly)oxyalkyl methacrylates, and mixtures thereof.

[0064] In one preferred embodiment, the crosslinking agent useful in the present invention is a diglycidyl ether. For example, the crosslinker may be based on crosslinking chemistry as shown by the following chemical structure (I): The crosslinker may be a diglycidyl ether type crosslinker, such as: [ka]

[0065] In the above structure (I), "n" is in one embodiment 3 to 25, in another embodiment 7 to 20, and in yet another embodiment, 9-15.

[0066] Examples of some commercially available crosslinking agents useful in the present invention include, for example, diglycidyl ether. Crosslinkers useful in the present invention based on diglycidyl ether chemistry are also included. Commercially available crosslinkers include, for example, those in which the product has structure (I) and n is equal to about 8 ( =) Epilox P13-42, the product has structure (I) and n=approximately 13 and Epilox M985 (both available from Leuna-Harze GmbH) Epilox M985 Poly(propylene glycol), and mixtures thereof. The diglycidyl ether crosslinker is a poly(ethylene glycol) diglycidyl ether crosslinker having a Mw of about 925 Da. Linear poly(propylene glycol) jig made from propylene glycol (PPG) It is a lysidyl ether.

[0067] Crosslinkers such as Epilox M985 and Epilox P13-42 have been shown to be beneficial. In particular, such crosslinkers are (1) non-toxic and (2) have very high boiling points (e.g., 2 00°C) / high Mw (e.g., above 600 g / mol), making this a preferred embodiment. This is an example of a gas that is (1) toxic and / or carcinogenic, and (2) has a low boiling point ( For example, 116°C) / low Mw (for example, 92.53 g mol -1 ) and (3) Known esters used in the prior art, such as epichlorohydrin, do not exhibit the desired increase in viscosity. This is in contrast to some of the crosslinker systems that have been developed.

[0068] With a crosslinker such as Epilox, the actual covalent bond is established between the cellulose ether This covalent bond formation favorably increases the Mw of the cellulose ether, making it more soluble in aqueous solution. The cellulose ethers of the present invention having a higher Mw provide the following advantages: properties, such as high viscosity levels in aqueous solutions (e.g., non-crosslinked (i.e., non-crosslinked) cellulose) In one embodiment, the viscosity is greater than 15% and in another embodiment, greater than 20% compared to that of to reach reduced dosage levels in applications (e.g., cement-based tile adhesives) and Provide a means for

[0069] Examples of some other advantageous properties exhibited by the crosslinker include the higher gel properties of XCE. The shift in crosslinking values ​​of XCE to lower frequencies compared to non-crosslinked cellulose ethers indicates In addition, when using the XCE of the present invention, for example, a mortar When used in a fluoropolymer formulation, the amount of XCE required to obtain the desired performance is reduced. Such a reduction in E dosage would then result in, for example, lower adhesion in cementitious tile adhesive applications. The cost of use correlates with the reduction in the amount of cellulose ether required to obtain the desired performance. Reduce the noise.

[0070] Generally, the amount of crosslinker used in the process of the present invention is from 0.0001 equivalents to 0.05 equivalents. The unit "equivalent" refers to the number of anhydroglucose units (AG) of the cellulose ether. The amount of crosslinker used in the process is generally In one embodiment, the amount is 0.0005 equivalents to 0.03 equivalents, and in another embodiment, the amount is 0.00 The amount of crosslinking agent used is 1 equivalent to 0.02 equivalent. If the amount of crosslinking agent used exceeds 0.05 equivalent, overcrosslinking occurs. Bridges may occur and the resulting XCE will be insoluble. If the amount of crosslinker used is less than 0.0001 equivalents, the viscosity of XCE increases in a 1% solution, for example. may not be detectable.

[0071] The crosslinking of the cellulose ether to produce the XCE of the present invention can be carried out, for example, by the process This can occur before, during, or after the etherification process step of the ester, but in the preferred embodiment In this embodiment, the crosslinking reaction is carried out after the etherification step and after the washing step and / or generated during the granulation step. Crosslinking cellulose ethers to produce XCE This is a well-known reaction, and is described, for example, in U.S. Pat. No. 6,958,393 B2. Generally, the cellulose ether that is subjected to crosslinking with the crosslinking agent is typically a hydroxyl group. It is a mixed cellulose ether containing dimethyl alkyl and alkyl ether groups. For example, in one embodiment, a mixed selenium copolymer containing hydroxyalkyl and alkyl ether groups is used. The cellulose ethers include alkyl hydroxycelluloses such as hydroxyalkyl methylcellulose. Contains ethyl cellulose.

[0072] In some embodiments, examples of cellulose ether compounds suitable for use in the present invention include As examples, methyl cellulose (MC), ethyl cellulose, propyl cellulose, butyl cellulose cellulose, hydroxyethyl methylcellulose (HEMC), hydroxypropyl methyl Cellulose (HPMC), Hydroxyethyl Cellulose (HEC), Methyl Hydroxyethyl MHEHPC, Ethyl Hydroxyethyl Cellulose cellulose (EHEC), methyl ethyl hydroxyethyl cellulose (MEHEC), hydrophobically modified Ethyl Hydroxyethyl Cellulose (HMEHEC), Hydrophobically Modified Hydroxyethyl Cellulose HMHEC, Sulfoethyl methyl hydroxyethyl cellulose (SEMHEC ), Sulfoethyl methyl hydroxypropyl cellulose (SEMHPC), Sulfoethyl Hydroxyethyl cellulose (SEHEC), and mixtures thereof. In some preferred embodiments, the mixed cellulose ethers are, for example, HEMC, HPMC, and mixtures thereof.

[0073] In the case of cellulose ethers useful in the present invention, the alkyl substitution is In biology, it is described by the term "DS" determined by the Zeisel method. is the average number of substituted OH groups per anhydroglucose unit. Methyl substitution is, for example, Hydroxyalkyl substitutions may be reported as DS(methyl) or DS(M). The term "MS" is used to describe the solubility of glucose in water, as determined by the glycerol method. The average number of moles of etherification reagent bound as ethers per mole of ether unit. Etherification with the etherifying agent ethylene oxide is, for example, MS (hydroxyethyl) or MS(HE). The alkylations are reported correspondingly as MS(hydroxypropyl) or MS(HP). The groups are determined using the Zeisel method (see G. Bartelmus and R .Ketterer, Z. Anal. Chem. 286 (1977), 161-190) .

[0074] The XCE produced by the process of the present invention may, for example, have a degree of alkyl substitution. For example, crosslinked HEC may be any of the cellulose ethers described above having the following structure: In another embodiment, the degree of substitution MS(HE) is 1.5 to 4.5, and in another embodiment, the degree of substitution MS(HE) is 2.0 to 3.0. In yet another embodiment, the methylcellulose is crosslinked. Mixed ethers of the following can be used in the process of the present invention. For example, in the case of HEMC, In one embodiment, the DS(M) value is 1.2 to 2.1, in another embodiment, 1.3 to 1.7, In yet another embodiment, the MS(HE) value is in the range of 1.35 to 1.6. is 0.05 to 0.75, in another embodiment is 0.15 to 0.45, and in yet another embodiment is In the case of HPMC, the DS(M) value is in the range of 1. In another embodiment, the range is 1.3 to 2.0, and the MS(HP In one embodiment, the value is in the range of 0.1 to 1.5, and in another embodiment, the value is in the range of 0.2 to 1.2. The range is.

[0075] After the above etherification step and washing / granulation step, the XCE product produced can be processed in various additional optional processing steps. For example, the resulting X CE is commonly used to produce cellulose derivative products and powders therefrom It may be further refined, dried, milled, and / or ground into a powder form using conventional methods. For example, the volatile organic constituents present in the XCE before or after cleaning can be It can be removed from the reduction or XCE product by distillation or steam stripping. Optional steps are well known to those of skill in the art and may be used to implement any of the above methods in accordance with the present invention. For example, after the above washing steps, typically, E is filtered to produce a filter cake, which is then subjected to a granulation step. Thus, among the various optional steps described above, one In one preferred embodiment, the XCE product is subjected to at least the drying and milling steps. to form a dry powder product for ease of handling, packaging and storage purposes. It is desirable.

[0076] Several advantageous properties are exhibited by the XCE produced by the above-mentioned method of the present invention. For example, aqueous solutions of XCE exhibit increased or ultra-high viscosity in aqueous solutions. The increased viscosity allows for a reduction in the dosage of XCE, for example in mortar mix applications. It becomes Noh.

[0077] For example, the increase in viscosity of the aqueous XCE solution produced by the process of the present invention is In one embodiment, more than 15%, and in another embodiment, More than 20%, in yet another embodiment more than 30%, and in yet another embodiment more than 50% Including viscosity increase.

[0078] In one broad embodiment, the XCE of the present invention is a dry mix mortar formulation, It can be used as an additive for cement milling, cement extrusion, etc. For example, dry milling In the process for preparing the mortar mix, the process comprises: (I) using a water-retaining agent (II) hydrolyzed binders, such as those containing cement or gypsum, The method includes the step of mixing the desired conventional dry mix mortar formulation ingredients.

[0079] In a preferred embodiment, the mortar formulation is prepared by conventional mixing as known in the art. mixing components (I) and (II) (e.g., a physical blend of solid powders) by Some of the advantageous properties exhibited by the mortar formulation include: Examples include the ability to use lower doses of XCE (>10%), resulting in The cost can be low. To prepare a mortar mix, generally, a water retention agent component (I) and The amount of XCE used is, for example, 0.01% by weight to 1.0% by weight in one embodiment. In another embodiment, 0.05% by weight to 0.8% by weight, and in yet another embodiment, 0.1% by weight Below these levels, the mortar will have insufficient water retention. Above these limits the cost of compounding becomes too high.

[0080] Conventional dry mix mortar ingredients, component (II), include, for example, cement, gypsum, Components such as hydrolyzed binders such as fly ash and furnace slag, as well as aggregates (sand), fine Fine fillers (calcium carbonate, fumed silica, dolomite, etc.), air entraining agents, defoaming agents , redispersible polymer powders, hydrophobic agents, and mixtures thereof. EXAMPLES

[0081] The following examples are presented to further illustrate the invention, but are not intended to be limiting of the scope of the claims. All parts and percentages are specifically and exclusively intended to be interpreted as limiting the scope of the present invention. Weights are by weight unless otherwise indicated.

[0082] Used in the following inventive examples (Inv. Ex.) and comparative examples (Comp. Ex.) The various terms and designations used are explained below and in Tables II-VI.

[0083] "HEMC" stands for hydroxyethyl methylcellulose.

[0084] "AGU" represents the anhydroglucose unit of the cellulose ether.

[0085] "LVN" was measured according to the procedure described in ISO 5351(2010). Represents the limiting viscosity number of pulp.

[0086] The various raw materials or components used in the examples are described as follows:

[0087] Epilox M985 and Epilox P13-42 are Poly(propylene glycol) diglycidyl ether available from Ze GmbH. do.

[0088] Comparative Examples A and B - Crosslinker Dosage in the Etherification Step Crushed cellulose floc (1.5 mol, LVN is 1,450 per gram) Milliliters [mL / g] or more (≧) in a 5 liter (L) autoclave (reactor) was added.

[0089] After purging the autoclave with N2 gas three times, the reactor was heated to 40°C. dimethyl ether (DME, 4.7 mol / mol AGU), and the first methyl chloride. The chill charge ("MCl 1", 3.2 mol / mol AGU) was added to the autoclave. The first caustic soda charge ("NaOH 1", 50% strength by weight, 1.9 mol NaOH / mol AGU) was added in three portions over a period of 2 minutes (min) at a temperature of 40°C. The reaction mixture was held at 40°C for 30 minutes. After 30 minutes, the ethanol was then added to the Ethylene oxide (0.45 mol / mol AGU) was added to the reaction mixture, and the reaction The reaction mixture was kept at 40° C. for an additional 10 minutes.

[0090] After 10 min, the indicated amount of crosslinker (0–0.003 mol / mol AGU of Epi lox M985) was added to the reaction mixture.

[0091] Dissolve in 20 milliliters (mL) of isopropanol and store the resulting solution for 30 seconds (3 The solution was added to the autoclave six times at intervals of 10 s.

[0092] The resulting mass was heated to 80° C. in 45 minutes. At 80° C., a second charge of methyl chloride ( "MCl2", 1.3 mol / mol AGU) was quickly placed in an autoclave. Then, a second caustic soda charge ("NaOH 2", 0.67 mol / m ol AGU) was added in seven portions over 30 min, followed by a 70 min cook time at 80°C. It was time for quarter-off.

[0093] After the above steps, the mass obtained from the autoclave was subjected to the following conventional process: The steps were carried out: hot water washing, granulation, and granulation using standard procedures known in the art. Drying, and milling.

[0094] Inventive Examples 1-3 and Comparative Example C - Granulation Step (see process shown in Figure 2) Administration of bridging agent Add 1,126.8 grams (g) of water-wet HEMC filter cable to the Loedige reactor. (dry content = 52.2%) [DS(M) 1.58, MS(HE) 0.29] was added. The filter cake was heated to 80°C in 60 min using a rotor speed of 180 / min (Synergy (Temperature: 125°C for 50 min, 97°C for 10 min) Then, 462.2 g of water was poured onto the reactor dome. The moisture content of the filter cake was increased to 63% by adding 100% water. Mixing was carried out for 30 minutes at 80° C. using the same rotor speed of 180 / min.

[0095] At 80°C, the crosslinker Epilox M985 (0–0.012 mol / mol AGU ) was added to the filter cake as follows: Epilox M985 was added first to the isopropanol. The resulting solution was then dissolved in isopropyl alcohol (IPA) (listed in Table II). Six additions were made to the filter cake at 2-second intervals. [Table 2]

[0096] The filter cake was mixed at 80°C for 120 minutes and then cooled to room temperature (approximately 23°C). An additional step of drying / grinding was then performed. [Table 3]

[0097] The processes of inventive examples 1-3 avoid the additional costs typically associated with dosing crosslinkers at high pressure. On the other hand, the known process (Comparative Example B) does not require such equipment. Requires costly equipment for administration.

[0098] Viscosity measurements were performed using a Haake RS 1 rheometer at a shear rate of 2.52 s -1 The experiment was carried out in a 1% aqueous solution at 20°C.

[0099] As can be seen in Table IV, using the process of the present invention, the state-of-the-art process was used. The XCE products had similar viscosity increases compared to non-crosslinked cellulose ethers. One advantage of the process of the present invention is that it allows the process to be used in a broader sense. For example, as shown in Table III, , 3mmol~

[0100] Increasing the amount of crosslinker to 6 mmol had minimal effect on the resulting viscosity of XCE. In contrast to using the comparative process, only a narrow process window is available. The administration of the crosslinking agent used in the present invention reduces the process time compared to comparative conventional processes. Overdosing has the added advantage that the window of success is enhanced. This results in a significant viscosity reduction where only a slight viscosity reduction is observed. [Table 4]

[0101] As shown by the results in Table IV, using the process of the present invention, a 49% increase in viscosity was observed. A 49% increase in viscosity was observed based on the comparative process (see Inventive Example 1 vs. Comparative Example C). The viscosity increase was almost the same (see Comparative Example B vs. Comparative Example A), but using the process of the present invention. The increased viscosity can be obtained with less process effort.

[0102] Comparative Examples D-F - Crosslinker: Epichlorohydrin used in the granulation step 1481 g of wet HEMC filter cake (dry content = 62%) [DS(M)1 0.32, MS(HE) 0.21) was added to the Loedige reactor and the rotor speed was 180 / The tube was heated to 80°C in 60 minutes using a 100°C kettle (sheath temperature 125°C for 50 minutes, 97°C for 10 minutes). Then, 40 g of water was added onto the reactor dome to bring the moisture content of the filter cake to 63%. Using the same rotor speed, the filter cake was mixed at 80° C. for 30 minutes.

[0103] At 80°C, the crosslinker epichlorohydrin (3 mmol / mol AGU)

[0104] Six 20 mL portions of isopropyl alcohol were added at 30 second intervals.

[0105] The filter cake was mixed at 80°C for 120 minutes and then cooled to room temperature. The cake was subjected to the following steps: drying and grinding. Results of Comparative Examples D-F [Table 5]

[0106] Inventive Examples 4-6 and Comparative Example G - Crosslinking at the Cleaning Step (see process shown in Figure 1) Administration of bridging agent 175 g of water-wet HEMC filter cake (dry content = 56%) [DS(M)1. 58, MS(HE) 0.29, NaCl 2.43%) were mixed in a high-speed mixer (10,000 r pm IKAT50 Basic Ultra Turrax Mixer, IKA® - 2-2.5 L of warm water (90 After 5 minutes, the MHEC was uniformly dispersed and the crosslinker Epilox P13 was added. -42 (0~0.015mol / mol AGU) was added. (Epilox MP1 3-42 was dissolved in 20 mL of IPA, and the resulting solution was added six times at 30 second intervals. The resulting suspension was stirred at a temperature above 90° C. for 2 hours. The resulting product was separated using a metal adsorbent. The resulting product was then subjected to the following process steps: Further processing was carried out using: granulation, drying and milling.

[0107] The process used in this example uses additional amines that are typically used to administer crosslinkers at high pressure. No expensive equipment was required. On the other hand, the comparative process did not require high pressure dosing of the crosslinking agent. This required expensive equipment.

[0108] The crosslinker used was Epirox P13-42, which has the following general chemical structure: where n is 9. [ka]

[0109] Epilox P13-42 is a polyoxypropylene glycol with a Mw of 680 g / mol. It is a diglycidyl ether based on lycohol.

[0110] Viscosity measurement takes 2.52 seconds -1 at 20°C using a Haake rheometer. The reaction was carried out with a 1 wt% aqueous solution of cellulose ether. [Table 6]

[0111] As shown in the results in Table VI, the XCE obtained using the process of the present invention A 44% increase in viscosity was observed (see Inventive Example 4 vs. Comparative Example G), which was , the same as the increase in viscosity of the XCE of the present invention compared to the XCE obtained using the conventional process. (See Table IV where Comparative Example B vs. Comparative Example A shows a 49% viscosity increase. However, the viscosity increase of XCE obtained using the process of the present invention is less. This can be achieved with little process effort, i.e., to obtain the beneficial viscosity increase of the XCE of the present invention. Therefore, no additional device for administering the crosslinking agent is required.

[0112] One additional advantage of the process of the present invention is that by using the process of the present invention , a wider process window becomes available. For example, As reported, an increase in the amount of crosslinker from 4 mmol to 15 mmol results in Minimal effect on viscosity of XCE as opposed to using the comparative process In contrast, the dosing of the crosslinking agent used in the present invention is relatively slow. The additional benefit is an enhanced process window compared to conventional processes. Overdosing is not sufficient to prevent viscosity loss in the process of the present invention. , resulting in a significant viscosity reduction.

Claims

1. 1. A process for producing a crosslinked cellulose ether, comprising: (a) contacting at least one cellulosic material with at least one alkalizing agent; forming an activated cellulose material; (b) subjecting the activated cellulose material of step (a) to at least one etherification reagent; with a drug to form a non-crosslinked cellulose ether; (c) subjecting the non-crosslinked cellulose ether of step (b) to (ci) a washing step and a granulation step, the washing step being carried out simultaneously; or (cii) a washing step and a granulation step, wherein the washing step is The washing and rinsing steps are separate from the grain step and are carried out separately in a step-by-step procedure. and a granulation step, or (ciii) a wash step only, or (civ) a granulation step only; 、 (d) at least one crosslinking agent and the non-crosslinked cellulose ether to form a crosslinked cellulose ether; and mixing the at least one crosslinking agent with the non-crosslinked cellulose ether to form a cellulose ether. adding to a tere, the cross-linking agent comprising: (di) during the washing step (ci) and during the granulation step (ci), teeth, (dii) during said washing step (cii) and during said granulation step (cii), ,or, (diii) only during said washing step (cii), or (div) only during the granulation step (cii), or (dv) during said washing step (ciii), or (dvi) the additives added to the process during the granulation step (civ) and

2. The crosslinked cellulose ether from step (d) is subjected to a step of purifying, drying, and and milling. The process of claim 1 , further comprising:

3. The at least one cellulosic material in step (a) is selected from the group consisting of wood pulp, cotton linters, and the like. and mixtures thereof, wherein said at least one of step (a) The alkalizing agents are sodium hydroxide, potassium hydroxide, lithium hydroxide, and the like.

2. The process of claim 1, wherein the mixture is selected from the group consisting of a solution of a mixture of

4. The at least one etherification reagent in step (b) is ethylene oxide, proton exchange copolymer, Pyrene oxide, butylene oxide, methyl chloride, ethyl chloride, and mixtures thereof The process of claim 1 , wherein the compound is selected from the group consisting of: 【Chemistry 1】

5. The at least one cross-linking agent in step (d) is a diamine having the following chemical structure (I): It is a glycidyl ether type crosslinking agent.

2. The process of claim 1, wherein n is 3 to 25.

6. The activated cellulose material of step (a) is heated at a pressure of 500 kilopascals or less.

2. The process of claim 1, wherein the catalyst is formed at a temperature of 50° C. or less.

7. The non-crosslinked cellulose ether of step (b) has a resistance of 1,000 kilopascals or more.

10. The process of claim 1 wherein the polymer is formed at pressure and at a temperature greater than 70°C.

8. Steps (c) and (d) are carried out at a pressure of 500 kilopascals or less. The process of claim 1 .

9. 2. The method of claim 1, wherein steps (a) and (b) are carried out in an inert atmosphere. The process of installation.

10. The etherification reagent of the contacting step (b) is 4 moles of said etherification reagent per mole of anhydroglucose unit 6 moles of said etherified glucose per mole of anhydroglucose units of said activated cellulose material The process of claim 1 , wherein the activated cellulose material is added at a concentration of 0.1% by weight.

11. The at least one cross-linking agent is added to the cellulosic acid in the adding step (d). 0.0001 mole of the crosslinker to the glucose ether per mole of anhydroglucose unit of the glucose ether At a concentration of 0.05 moles of said crosslinker per mole of anhydroglucose unit of the cellulose ether The process of claim 1 wherein

12. Compressing the at least one cellulose material to form a comminuted cellulose flock material. The method further comprises forming a powder of the mixture, the grinding step being carried out by grinding the mixture of the first and second powders of step (a). prior to contacting the at least one cellulose material with the at least one alkalizing agent. The process of claim 1 is carried out.

13. 13. A crosslinked cellulose ether produced by the process of claim 1.

14. A dry mix mortar formulation comprising: (I) the crosslinked cellulose ether according to claim 13; (II) a hydrolysis binder, wherein the hydrolysis binder is a cement or gypsum material. A dry mix mortar compound.

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