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: A process for producing a crosslinked cellulose ether includes contacting an activated cellulose material with (i) an aqueous crosslinking agent emulsion, including (ia) at least one crosslinking agent and (ib) water, and (ii) at least one etherification reagent, wherein the aqueous crosslinking agent emulsion and the at least one etherification reagent react with the activated cellulose material to form a reaction mixture to produce the crosslinked cellulose ether.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 wear 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. After the cellulose ether is prepared, (3) the cellulose ether is washed; (4) drying the cellulose ether; and (5) 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, and inert atmosphere, such as nitrogen (N 2 ), the 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; (5 ) The product obtained as a result of the process must exhibit good performance. The above requirements are necessary. In addition, the use of the above known processes may result in the crosslinking agent in the reactor being This results in poor distribution, which can lead to over-crosslinking and undesirable viscosity reduction of the crosslinked cellulose product. Also, the efficiency of the known process of U.S. Patent No. 6,958,393 B2 is From laboratory scale to pilot plant scale and / or ultimately to full-scale industrial plants Therefore, the above known processes are not easily transferred to plant scale and It requires a great deal of expertise, knowledge and technical effort to operate under known process conditions. It is necessary.

[0010] 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. This is achieved to create branched polymers and prevent local overdosing that can lead to overcrosslinking. Overcrosslinking (i.e., high levels of crosslinking) can lead to localized crosslink networks. Excessive crosslinking leads to increased levels of cellulose ethers and localized insoluble material. When and at what stage, step or operation of the polymer manufacturing process is the crosslinker introduced into the process? For example, the crosslinking agent may be added before, during, or after the etherification procedure. However, the alkalinization and etherification reactions The reaction is exothermic and may affect whether overcrosslinking occurs in the process. There are many factors that can affect this, including the reaction time, the crosslinking agent introduced into the process, etc. the type of crosslinker, the amount of crosslinker introduced into the process, the manner in which the crosslinker is introduced into the process, The process conditions at the time the agent is introduced and for how long the crosslinker is introduced into the process or may be included. Summary of the Invention [Problem to be solved by the invention]

[0011] Therefore, it is useful and can be used in industrial plants with higher efficiency than known conventional processes. A novel and improved method for producing crosslinked cellulose ethers that can be implemented on a pilot scale. It is desirable to provide a process that improves the quality of the product and at the same time, The performance of the resulting product is equal to or better than known products from conventional processes. It remains as it is.

[0012] 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

[0013] The present invention relates to a method for preparing an activated cellulose material by combining (i) an aqueous crosslinker emulsion, and (ii) ) contacting the aqueous crosslinker emulsion with at least one etherification agent; and at least one etherification reagent reacts with the activated cellulose material to form an XCE. The present invention is directed to a process for producing XCE, comprising forming a reaction mixture comprising: XCEs include, for example, hydroxyethyl methylcellulose derivatives. XCEs are aqueous crosslinking agents. Crosslinking Agent The crosslinking agent is formed in the presence of at least one crosslinking agent present in the emulsion. In a preferred embodiment, the aqueous crosslinker emulsion comprises (ia) at least one crosslinker; (ib) water, and (ic) any other optional ingredients as desired.

[0014] In another preferred embodiment, the present invention provides a process for producing a cellulose acylate comprising: (A) mixing at least one crosslinking agent with water; (B) adding an activated cellulose material to form an aqueous crosslinker emulsion; and Bi) the crosslinker emulsion of step (A) and (Bii) at least one ether and contacting the activated cellulose material with a activating agent to form a reaction mixture that reacts with the activated cellulose material to form the XCE. (C) optionally purifying, washing and drying the XCE from step (C). and performing one or more steps of: The purpose of this document is to cover the process of

[0015] In yet another preferred embodiment, the aqueous crosslinker emulsion is Introduced or added to a process.

[0016] In yet another embodiment, the present invention relates to the XCE produced by the above process. The XCE produced by the above process of the present invention advantageously has high water solubility. which leads to an increased viscosity in aqueous solution when compared to non-crosslinked cellulose ethers.

[0017] Yet another embodiment of the present invention is a dry mix mortar formulation comprising the XCE described above. The present invention relates to a composition.

[0018] Use of the process of the present invention provides an efficient manufacturing process for making XCE. Surprisingly, crosslinkers such as diglycidyl ethers are easily dispersible in water. The resulting aqueous dispersion is easily distributed throughout the contents of the large reactor and It has been found that the present invention can provide a more uniform distribution of the crosslinking agent in the aqueous solution. It is possible to avoid the partial formation of over-crosslinked particles that are not functional. The use of crosslinkers is much more effective in aqueous dispersions than in organic solvents, since The overall dosage of crosslinker can be reduced while the efficacy of the crosslinker remains excellent. Cut.

[0019] Some other advantages of the process of the present invention include, for example: (1) large-scale plant process (2) there is no over-crosslinking in the crosslinker (only the desired viscosity increase); (3) The process requires only a small amount of crosslinker, so (4) the dosage is significantly reduced, and small amounts of crosslinker are used in large plant-scale processes. Moreover, the process of the present invention advantageously allows for uniform distribution of the already X has the same or better performance characteristics as a known product prepared by a known process In addition, the process of the present invention advantageously provides an acetonitrile product. With the crosslinker dosages used in the tertiary step, large crosslinking rates were achieved without overcrosslinking issues. It can be carried out on a plant scale. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 is a schematic flow diagram illustrating the process of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] 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.

[0022] The "aqueous crosslinker emulsion" in this disclosure is easily prepared during etherification and and at least one of the activated cellulose materials exhibiting the advantageous property of being uniformly distributed throughout the activated cellulose material. The crosslinker emulsion of the present invention is a useful composition comprising a combination of the crosslinker and water. It is also desirable that the final XCE product be non-toxic and soluble in aqueous solutions. The use of the aqueous crosslinker emulsion of the present invention also provides an XCE having an increased viscosity. Advantageously, over-crosslinking during etherification is prevented or at least minimized.

[0023] Generally, the process for producing XCE includes an alkalinization step and an etherification step. The alkalizing step may be preceded by a grinding step, typically In principle, it is desirable to use water (high temperature H 2 O) washing / granulation step and / or drying / The milling step can be carried out after the etherification step. In the etherification step, a cross-linking agent is added to the etherification operation to increase the cellulose during the etherification step. Provides crosslinking of the aryl ether.

[0024] 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 in the form of an emulsion to the etherification step or process operation, or is administered.

[0025] The small amount of crosslinking agent used in the present invention provides the same rheological performance as known products (e.g. High viscosity levels (measured in millipascal seconds [mPa.s]) but with higher efficiency Advantageously, this results in an ultra-high viscosity product using a crosslinker, which in turn results in less unwanted side reactions. The level of chlorine is reduced and the impact on wastewater treatment is minimized. The dosage of cross-linking agent is reduced to prevent over-cross-linking.

[0026] The dosage of the crosslinking agent used in the present invention is such that water is used as the suspension medium for the crosslinking agent. The advantage is that the objective of uniform distribution is easier to achieve compared to conventional processes. In addition, the present invention uses an aqueous crosslinker emulsion as a diluent for the crosslinker. As with processes known in the art that use organic solvents, It is free of the safety and environmental concerns associated with

[0027] Further advantages of the process of the present invention include, for example, (1) the process is Dye-based diglycidyl ether chemistry such as 985 or Epilox P13-42 (2) Uses readily available crosslinking agents; the emulsion is non-toxic and has a very high boiling point; and has a high molecular weight (Mw) (e.g., 600 grams / mole [g / mol] In contrast, the known process uses epichlorohydrin as the crosslinker system. Such a known process uses, for example, epichlorohydrin. It is known to be toxic, carcinogenic, and has a low boiling point (116°C) / low Mw (92 It suffers from several disadvantages, including having a molecular weight of 0.53 g / mol. Table I shows a comparison of the physical data for the Epilox products versus epichlorohydrin. [Table 1]

[0028] The process of the present invention has beneficial rheological behavior and is useful in a variety of application areas. The present invention provides an irreversibly crosslinked cellulose ether that is advantageous in that it can be used to prepare a cellulose ether having a high molecular weight and a high molecular weight. As a crosslinking agent for preparing the ethylenediaminetetraacetate, a C10-C24 alkyl bifunctional compound (oxirane and / or halogenated) or polypropylene glycol diglycidyl ether The process of the present invention uses an aqueous emulsion to carry out the etherification step of the process. The prior art uses ECH as a crosslinker to prepare XCE. The process often results in insoluble crosslinked products, and the crosslinkers are less environmentally friendly than ECH. There are fewer concerns.

[0029] Generally, the crosslinker dispersion or emulsion compositions useful in the present invention comprise: (i) a crosslinker; , (ii) water, and (iii) any other optional ingredients as desired.

[0030] The crosslinking agent (or agents) used to prepare the cellulose ethers of the present invention are , for example, one or more crosslinking agents known in the art. In terms of form, crosslinkers useful in the present invention are generally water-insoluble or poorly water-soluble crosslinkers. In a preferred embodiment, the crosslinking agent is added to the aqueous process, e.g. For example, it may be water-insoluble to prevent hydrolysis and other undesirable side reactions from occurring. or crosslinkers with a water solubility of less than (<) 10 percent (%) may be used. "Water insoluble" refers to a crosslinker that has no water solubility or has a water solubility of <10%. It refers to a crosslinker that has low (weak or poor) water solubility. In another embodiment, the crosslinker The water solubility of the crosslinking agent can be 0% to <9% and 0% to <8%. This can be measured by turbidity analysis, which is well known in the art.

[0031] For example, the water-insoluble nature of the crosslinking agent may result in the hydroxyl (-OH) groups of the cellulose backbone Optimization of the desirable side reaction with sodium hydroxide ( Undesirable side reactions with the -OH groups of NaOH are minimized.

[0032] 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 epichlorohydrin, glycidyl (poly)oxygen, dimethyl methacrylate, dimethyl methacrylates, and mixtures thereof.

[0033] 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]

[0034] 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.

[0035] Several commercially available crosslinkers useful in the present invention are available, such as diglycidyl ether chemistries. Examples of crosslinkers based on Epilox P13-42 and Epilox M 985 (both available from Leuna-Harze GmbH). M 985 Poly(propylene glycol) diglycidyl ether crosslinker is a Linear poly(propylene glycol) diglycidyl esters prepared from polypropylene glycol (PPG) It is ether.

[0036] With a crosslinker such as Epilox M 985, the actual covalent bond formation occurs This construction of covalent bonds advantageously strengthens the cellulose backbone of the cellulose ether. The cellulose ether with a bright and reinforced cellulose backbone has the following advantages: For example, Epilox M 985 and Crosslinkers such as Epilox P13-42 and Epilox P13-42 provide beneficial properties. For example, a preferred crosslinking agent is one that is (1) non-toxic and (2) High boiling point (e.g., above 200°C) and high Mw (e.g., 600 g / mol This is because the known amines used in the prior art, such as epichlorohydrin, have a molecular weight of 1.21g or more. In contrast to some of the crosslinker systems used, (1) they are toxic and / or carcinogenic; (2) low boiling point (e.g., 116°C) and low Mw (e.g., 92.53 g / mol ) and (3) does not exhibit the desired increase in viscosity.

[0037] In addition, when using the XCE of the present invention, for example when used in a mortar mix, The amount of XCE required to achieve desired performance is reduced compared to non-crosslinked cellulose ethers. Such a reduction in XCE dosage would then be beneficial for applications such as cementitious tile adhesives. This correlates with a reduction in the amount of cellulose ether required to obtain the desired performance. Reduces usage costs.

[0038] Generally, the amount of crosslinker emulsion used in the process of the present invention is about 0.0001 equivalents. The amount of the anhydrous glycol of the cellulose ether may range from 0.05 equivalents to 0.05 equivalents. The molar ratio of crosslinker to moles of AGU is given in the formula (I). The amount of the crosslinking agent used in the above step is, for example, 0.0005 to 0.03 equivalents in one embodiment. In another embodiment, the amount of crosslinking agent used is 0.001 equivalents to 0.005 equivalents. If the amount exceeds 0.05 equivalents, over-crosslinking may occur, and therefore the XCE becomes insoluble. If the amount of crosslinker used is less than 0.0001 equivalents, e.g. For example, the increase in viscosity of a 1% solution may not be detectable.

[0039] The water used to form the crosslinker emulsion may be obtained from any source. Different types of water include, for example, tap water, drinking water, and deionized water.

[0040] The crosslinker emulsion is used in the etherification step of the process to make the XCE of the present invention. The crosslinker and water are mixed by conventional mixing means either before or just before adding the emulsion. In one preferred embodiment, the crosslinker is formed by, for example, reacting 5 For example, the amount of crosslinker in water is in one embodiment 10 to 100% emulsion. Weight percent (wt%) to 90 wt%, in another embodiment 20 wt% to 80 wt%, or In yet another embodiment, it is 30% by weight to 70% by weight.

[0041] In one general embodiment, the crosslinker emulsions useful in the present invention are prepared by The process includes mixing (a) at least one crosslinker with (b) water to form a crosslinker emulsion. The mixing of the crosslinker and water to form the emulsion includes any The crosslinking may be carried out by any conventional mixing means, such as a horizontal or vertical mixer. Mixing can occur by pumping the agent into the water or by connecting it to the water supply line. It is combined with a bridging agent.

[0042] One example of an advantageous property exhibited by the crosslinker emulsion is that the emulsion is easily and uniformly distributed on the activated cellulose material during etherification.

[0043] In one broad embodiment, the process for producing XCE from a cellulosic starting material comprises: A) mixing at least one crosslinker with water to form an aqueous crosslinker emulsion as described above; (B) forming an activated cellulose material by (Bi) crosslinking the crosslinker emulsifier of step (A); and (Bii) at least one etherification reagent to form a reaction mixture. reacting to form XCE in the presence of at least one crosslinking agent. and forming an XCE.

[0044] Referring to FIG. 1, there is shown a process of the present invention, generally designated by the reference numeral 10. The viscosity of the aqueous solution is increased, for example to produce XCE, which is useful in dry mix mortars. Various general process operations or steps for the process are shown. As shown in Figure 1, The process may be carried out, for example, by the addition of alkali, as indicated by arrows 11a and 12a, respectively. A cellulosic starting material 11 such as pulp and an alkalizing reagent which proceeds to a polymerization step 13. In the alkalinization step 13, the alkalinization reagent 12 is indicated by arrow 13a. As shown, it is mixed with cellulosic material 11 to form activated cellulose 14 . The formed activated cellulose 14 is subjected to an etherification step, as indicated by arrow 14a. In the etherification step 15, the etherification reagent 16 is introduced by arrow 16a. As shown in FIG. 1, the cellulose ether is formed by introducing the cellulose ether into the etherification step 15. Also, what is introduced into the etherification step 15 is, as shown by the arrow 17a, The aqueous crosslinker emulsion 17 is added to the etherification step 15. The ion 17 is in contact with the activated cellulose ether 14, as indicated by arrow 15a. Thus, XCE18 is formed proceeding from the etherification step 15.

[0045] Referring again to FIG. 1, the optional grinding step 21 shown in dotted lines in FIG. As shown by arrow 21a, the cellulose material 11 is subjected to the As shown by a, the ground particulate cellulose then proceeds to the alkalization step 13. The milling step 21 is optional, but may be used to provide a milled cellulose material. Step 21 typically involves grinding a cellulosic starting material 11 (e.g., wood pulp) to produce a cellulose-based product. , resulting in comminuted flocs of cellulose that can flow and mix easily in the reactor. In the preferred embodiment, the crushed floc is used so that it can be formed. In addition, the cellulose flocs mixed in the reactor are sprayed with alkali using conventional spraying means. The alkalizing agent is easily contacted with the surface of the substrate, such as by spraying the alkalizing agent.

[0046] In another embodiment, XCE 18 from etherification step 15 is represented by arrow 18a. As shown in FIG. 1, one or more additional optional operations or Step 22 can be optionally performed in accordance with the present invention. Typically, one or more of steps 22 will be desired and used in the process. Optional step 22 may include, for example, (1) water (high temperature H 2 O) wash (2) a granulation step to form XCE granules; (3) a granulated XCE and (4) a milling step to form the XCE into a powder product. Each of the above optional steps may be selected from a single step. Any of the above optional steps may be performed in a single operation, if desired. Two or more can be combined into a single operation.

[0047] For example, XCE18 after the etherification step 15 typically produces unwanted volatile by-products. The product and salt (NaCl) are thus obtained, and in a preferred embodiment, the etherification step XCE 18 after step 15 is a cleaning step 22 as shown by arrow 18a. This process removes unwanted volatile by-products, salts, and other impurities from the XCE. This is followed by a drying step 22.

[0048] The starting material used to prepare the cellulose ethers of the present invention is cellulose. Cellulosic pulp is typically made from, for example, wood pulp or cotton linter pulp. The pulp is typically ground using conventional grinding means to produce a flour or flour. In one preferred embodiment, the cellulose is provided in a rock form. Possible cellulose starting materials include ground wood pulp, ground linter cellulose, and and mixtures thereof. In another preferred embodiment, wood pulp is used in the process. The wood pulp is used as the cellulose feed when it is fed to the alkalization process step. It is ground into comminuted flocs of cellulose as a means of making the material more fluid. In one embodiment, the pulp may be, for example, 1,000 microns (μm) to 10 μm. In this embodiment, the powder is crushed to particles of an optimum size of 900 μm to 20 μm. The efficiency of the alkalinization step may decrease, and the finer the particle size, the longer it takes to grind. Prior to the alkalinization step, the reactor is typically Filled with Lupflock.

[0049] The alkalized or "activated" cellulose material used to form XCE is at least one alkalizing agent (or or an alkalizing agent) with at least one cellulosic material. Alkalizing agents useful during the alkalinization step of the process of the present invention include, for example, those known in the art. The alkalizing agent may include one or more alkalizing agents known in the art. However, for economic reasons, One preferred solution is an alkali metal hydroxide, such as aqueous sodium hydroxide (NaOH). In an embodiment, the native cellulose or cellulose hydrate when carrying out the process of the present invention In other embodiments, other alkaline aqueous solutions, e.g. For example, potassium hydroxide (KOH) or lithium hydroxide (LiOH) solutions are also alkaline. In a preferred embodiment, the alkali metal ion used in the present invention is suitable for use as a cationizing agent. Metal hydroxides were available from The Dow Chemical Company. It is 0% caustic soda.

[0050] Generally, the alkalizing agent is in the form of a mixture of alkalizing agent in water, and the aqueous solution The concentration may vary within a wide range. In some embodiments, the aqueous solution is suitably In one embodiment, about 30% to 70% by weight, in another embodiment, about 40% to 60% by weight, In another embodiment, the range is 45% by weight to 55% by weight. The solution is used as a 50% reagent in water.

[0051] The amount of alkalizing reagent added to the XCE manufacturing process is, in one embodiment, 2 mol / mol AGU to 4 mol / mol AGU, in another embodiment 2.5 mol / mol AGU 3.5 mol / mol AGU, and in yet another embodiment, 2.7 mol / mol AGU~3.2mol / molAGU.

[0052] The alkalinization step of the process is carried out under low pressure and low temperature conditions. The pressure in the calcination step is in one embodiment from 0 kilopascals (kPa) to 500 kPa; In another embodiment, the pressure is 100 kPa to 400 kPa, and in yet another embodiment, the pressure is 200 kPa to The pressure range is typically in the range of 300 kPa in the reactor during the alkalinization step. Also, for example, the temperature of the alkalinization step of the process is In one embodiment, the temperature is 10° C. to 50° C., in another embodiment, the temperature is 15° C. to 45° C., and in yet another embodiment, the temperature is 15° C. to 45° C. The temperature range is 20°C to 40°C. The above temperature range is the temperature range in the reactor during the alkalinization step. Typical temperature ranges. Higher temperatures used in the process of the present invention can result in undesirable This would result in a large pressure rise.

[0053] To produce cellulose ethers according to the process of the present invention, the etherification reagent is The cellulose is mixed with the activated cellulose material prepared in the alkalization step above. Etherification reagents used to prepare the ethers include, for example, those known in the art. The etherification reagent may include one or more etherification reagents. For example, the etherification reagent may be ethylene oxide. ethylene oxide (EO), propylene oxide (PO), butylene oxide (BO), methyl chloride ( MCl), ethyl chloride, chloroacetic acid, and mixtures thereof. In embodiments, etherification reagents useful in the present invention include, for example, MCl, PO, EO, and mixtures thereof.

[0054] The amount of etherification reagent added to the etherification operation of the XCE production process may be, for example, In one embodiment, 4 mol / AGU to 6 mol / AGU, and in another embodiment, 4.5 mol / AGU GU to 5.5 mol / AGU, and in yet another embodiment, 4.7 mol / AGU to 5 .3 mol / AGU if the amount of etherification reagent used is <4 mol / AGU However, the cellulose ethers may be undersubstituted and not completely water soluble. If the amount of etherification reagent used is >6 mol / AGU, this high dosage of etherification reagent This can render the cellulose ether hydrophobic and reduce its water solubility.

[0055] An etherification reagent added to the etherification step to contact the activated cellulose The addition may be by any known means, for example by pumping a liquid compound into the reactor. This can be implemented by:

[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, N 2 , 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, 1,000 kPa to 3,500 kPa in one embodiment. a, in another embodiment, 1,500 kPa to 3,000 kPa, and in yet another embodiment, 2 At pressures of <1,500 kPa, the reaction The speed is too slow and at pressures >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 120° C. in one embodiment. In another embodiment, the temperature is in the range of 70° C. to 110° C., and in yet another embodiment, the temperature is in the range of 80° C. to 100° C. At temperatures <60°C the reaction rate is unacceptably slow. At temperatures >100°C In this case, unwanted side reactions may occur and the pressure may increase. For example, if the pressure is increased to 2,500 If the pressure rises above kPa, a different pressure reaction can be used that can handle higher pressures and is more expensive. A response device will be needed.

[0059] The crosslinking action of the activated cellulose ether to produce the XCE of the present invention is When the crosslinker emulsion is added to the etherification operation of the process and The esterification process step begins as it proceeds. The crosslinker additive used in the crosslinker addition step of the inventive process is The amount of emulsion is determined by the amount of crosslinker present in the etherification step, as described above, from 0.000 to 0.000. It is in the range of 1 equivalent to 0.05 equivalent.

[0060] The crosslinker emulsion is used to prepare the cellulose ether product formed during the etherification step. It is added to the etherification step when it is added to the crosslinker emulsion addition step of the process. The pressure of the cap is, for example, 1,000 kPa to 3,500 kPa in one embodiment, In one embodiment, the pressure is 1,500 kPa to 3,000 kPa, and in another embodiment, the pressure is 2,000 kPa. The range is a~2,500kPa.

[0061] The temperature of the crosslinking agent addition step of the process is, for example, 60° C. to 120° C. in one embodiment. In another embodiment, the temperature is in the range of 70° C. to 110° C., and in yet another embodiment, the temperature is in the range of 80° C. to 100° C. At temperatures <60°C the reaction rate becomes unacceptably slow and at temperatures >100°C At temperatures above 3.00 degrees, unwanted side reactions may occur and the pressure may increase. If the pressure rises above 0 kPa, a different, more expensive pressure reactor is required that can handle the high pressures. become.

[0062] Generally, the crosslinker emulsion is added to the etherification step of the process to activate The cellulose material is mixed with the activated cellulose material in the etherification step. The etherification reagents used generally form homogeneous reaction mixtures. The compound reacts to form the XCE product. It is used in a crosslinking reaction with the crosslinker emulsion. The cellulose ethers typically contain hydroxyalkyl and alkyl ether groups. For example, in one embodiment, the hydroxyalkyl cellulose ether is Mixed cellulose ethers containing hydroxyl and alkyl ether groups include and alkyl hydroxyethyl celluloses such as alkylmethyl cellulose.

[0063] In another embodiment, examples of cellulose ether compounds suitable for crosslinking include methyl cellulose, cellulose (MC), ethyl cellulose, propyl cellulose, butyl cellulose, hydroxy Ethyl methylcellulose (HEMC), Hydroxypropyl methylcellulose (HPMC ), Hydroxyethyl Cellulose (HEC), Methyl Hydroxyethyl Hydroxypropyl methyl cellulose (MHEHPC), ethyl hydroxyethyl cellulose (EHEC), Hydrophobically modified ethyl hydroxyethyl cellulose (MEHEC) Hydrophobically modified hydroxyethyl cellulose (HMEHEC), Hydrophobically modified hydroxyethyl cellulose (HMHEC) , Sulfoethyl methyl hydroxyethyl cellulose (SEMHEC), Sulfoethyl methyl Sulfoethyl Hydroxypropyl Cellulose (SEMHPC), Sulfoethyl Hydroxyethyl Cellulose Some preferred embodiments include, but are not limited to, sucrose, glycerin, sucrose, glycerol, sucrose, sucrose esters (SEHEC), and mixtures thereof. In the present invention, the mixed cellulose ethers are, for example, HEMC, HPMC, and mixtures thereof. may include.

[0064] In the case of cellulose ethers useful in the present invention, the alkyl substitution is In chemistry, it is described in terms of "degree of substitution DS" determined by the Zeisel method. DS is the average number of substituted OH groups per anhydroglucose unit. Methyl substitutions, for example, Hydroxyalkyl substitution can be reported as DS(methyl) or DS(M). It is described by the term "molar substitution MS" as determined by the Feisel method. MS is is the average molar mass of the etherification reagent bound as an ether per mole of anhydroglucose unit. Etherification with etherification reagent EO is, for example, ) or MS(HE). Etherification with the etherification reagent PO is reported as MS The side groups are reported correspondingly as Tsai (hydroxypropyl) or MS(HP). The β-aspartate β-aspartate is determined using the Zelle method (see G. Bartelmus and R. Ketten rer, Z. Anal. Chem. 286 (1977), 161-190).

[0065] The XCE produced by the process of the present invention may, for example, have a degree of alkyl substitution. For example, in one embodiment, the crosslinked HE C has a degree of substitution MS(HE) of 1.5 to 4.5, and in another embodiment, 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 preferred embodiment, the DS(M) value is 1.2 to 2.1, in another embodiment, 1. In another preferred embodiment, the ratio is in the range of 3 to 1.7, and in another preferred embodiment, the ratio is in the range of 1.35 to 1.6. In one embodiment, the MS(HE) value is 0.05 to 0.75, and in another embodiment, 0.15 to 0.4. 5, and in yet another embodiment, it may range from 0.20 to 0.40. For HPMC, 1 In one preferred embodiment, the DS(M) value is 1.2 to 2.1, and in another embodiment, 1.3 In yet another preferred embodiment, the MS(HP) value may range from 0. It may be in the range of 1 to 1.5, and in another embodiment, 0.2 to 1.2.

[0066] After the above etherification step, the XCE product produced may be optionally subjected to various additional For example, the resulting XCE can be treated with a cellulose derivative. The product and powders therefrom are washed using conventional methods typically used to produce the product. It can be purified or refined, granulated, dried, and / or milled into a powder form. For example, Before or after cleaning, the volatile organic constituents present in the XCE may be removed by distillation or steam. It can be removed from the reduction or XCE product by stripping. The steps are well known to those skilled in the art.

[0067] Some of the XCE products produced by the above process of the present invention are shown to be Advantageous properties include, for example, the ability to be easily dosed in dry mix mortar formulations without compromising performance. Increasing the viscosity of the aqueous solution may be included to allow for a reduction in the amount of

[0068] For example, the increase in viscosity of the aqueous XCE solution produced by the process of the present invention is In one embodiment, the crosslinked cellulose ether is >15% by weight when compared to a non-crosslinked aqueous solution of cellulose ether based on a cellulose source. %, in another embodiment >20%, in yet another embodiment >30%, and in yet another embodiment Embodiments include a viscosity increase of >50%.

[0069] In one broad embodiment, the XCE of the present invention is a dry mix mortar formulation, It can be used as an additive for drilling, cement extrusion, etc. For example, dry mix In the process of preparing a mortar mix, the process uses (A) a water-retaining agent. (B) a desired binder, such as a hydrolyzed binder containing cement or gypsum. and mixing the conventional dry mix mortar ingredients.

[0070] In a preferred embodiment, the mortar formulation is prepared by conventional mixing as known in the art. mixing components (A) and (B) (e.g., a physical blend of solid powders) by Some advantageous properties exhibited by the mortar formulation include, for example: Examples include the ability to use lower doses of XCE (>10%), resulting in reduced formulation costs. In order to prepare a mortar mixture, water retention agent (A) is generally used. The amount of XCE used in one embodiment is, for example, 0.01% by weight to 1.0% by weight, in another embodiment, In one embodiment, the concentration is 0.05% by weight to 0.8% by weight, and in yet another embodiment, the concentration is 0.1% by weight to Below these levels the water retention of the mortar becomes insufficient. Above these limits the cost of formulation becomes too high.

[0071] Conventional dry mix mortar ingredients, component (B), include, for example, cement, gypsum, Components such as hydrolyzed binders such as fly ash and furnace slag, as well as aggregates (sand), fine Fillers (calcium carbonate, fumed silica, dolomite, etc.), air entraining agents, defoaming agents, Redispersible polymer powders, hydrophobic agents, and mixtures thereof may be included. EXAMPLES

[0072] The following examples are presented to further illustrate the invention, but are not intended to be limiting of the scope of the claims. The scope of the present disclosure should not be construed as limiting the scope of the present disclosure. All parts and percentages are subject to change without notice. Unless otherwise stated in weight.

[0073] Various compounds used in the invention examples (Inv. Ex.) and comparative examples (Comp. Ex.) The terms and designations are explained as follows: "HEMC" stands for hydroxyethyl methylcellulose. "AGU" represents the anhydroglucose unit of the cellulose ether. "LVN" is a performance index measured according to the procedure described in ISO 5351 (2010). This represents the limiting viscosity number of the polymer.

[0074] The various raw materials or components used in the examples are described as follows: Epilox M 985 is a poly(propylene glycol) copolymer available from Leuna Harze. It is diglycidyl ether of ethylene glycol.

[0075] Crosslinking agents based on diglycidyl ethers that can be used in the process of the present invention An example of a compound is Eugene W. Jones, Crosslinking of Cot ton Cellulose with Diglycidyl Ether,Jour nal of Applied polymer science,Vol.V,iss ue no 18, 714-720 (1961).

[0076] Test Method Insoluble Content The cellulose ether samples were dissolved in water: 1.0 parts by weight of HEMC and 1.0 parts by weight of water. 99.0 parts per volume. HEMC (dry basis) should be mixed with stirring to avoid the formation of lumps. Then, it was dispersed in water at room temperature (about 25°C).

[0077] 50 g of HEMC solution was purchased from Thermo Scientific Sorvall Centrifuge in a Lynx 4000 centrifuge at 13535 UPM for 30 minutes (min) The insoluble material ("insolubles") of the prepared solution collected at the bottom of the centrifuge vial. do.

[0078] A specified amount of the overstanding solution was weighed out and heated at 105°C in a drying cabinet. The residue was weighed and the soluble content was calculated. When pulled, the insoluble contents are expelled.

[0079] Inventive Examples 1 and 2 and Comparative Examples A-C Generally, HEMC is produced according to the principles of Williamson ether synthesis. The cellulose is activated with 50% caustic soda to produce alkalized cellulose. This is followed by etherification with MCl and EO. For example, see R. Donges, "Non-Ionic Cellulose Et hers”, British Polymer Journal Vol. 23, pp. 315-326 (1990). The cross-linking compounds used in the process of the present invention are The characteristics of the crosslinkers used in the examples, based on diglycidyl ethers, are summarized in Table II. Posted.

[0080] The limiting viscosity number (LVN) of the pulp was determined according to the procedure described in ISO 5351 (2010). The LVN was measured according to the following formula: 1,450 milliliters or more (≧) [mL / g] per 1,000 liters (L) The mixture was added to the autoclave (reactor).

[0081] Autoclave with N. 2 After purging three times with 500 rpm, the autoclave was heated to 40°C. Then, dimethyl ether (DME, 4.7 mol / mol AGU), and the first salt A charge of methyl chloride ("MCl 1", 3.2 mol / mol AGU) was autoclaved. The first caustic soda charge ("NaOH 1", (50% strength, 1.9 mo Autoclave the solution in three portions (100 ml NaOH / mol AGU) for 2 min at 40°C. The mixture was then kept at 40° C. for 30 minutes. O (0.45 mol / mol AGU) was added to the mixture in the autoclave, and the resulting The reaction mixture was kept at 40° C. for 10 minutes. The crosslinker was then sprayed into the autoclave reactor. did.

[0082] The crosslinker of the present process is prepared by mixing water and the crosslinker before the emulsion is added to the reactor. The emulsion was then prepared by thoroughly mixing the aqueous phase with water. Immediately after the emulsion was generated, it was sprayed into the reactor. The pure crosslinking agent was sprayed into the reaction mixture in the reactor.

[0083] The mass formed in the reactor was heated to 80° C. in 45 minutes. At 80° C., the second MCl charge was added. The charge ("MCl2", 1.3 mol / mol AGU) was rapidly injected into the mass. , the second caustic soda charge ("NaOH2", 0.67 mol / mol AGU) is added to 30 The mixture was added in seven portions over a period of 10 minutes followed by a 70 minute cook off period at 80°C. After 70 minutes of cook-off time, the resulting XCE product was formed. The E product is subjected to the following process steps using conventional procedures known in the art: The procedure was as follows: hot water washing, neutralization with formic acid, granulation using a lab granulator (Bosch Mum), Drying, and milling.

[0084] Comparative Example A, Inventive Example 1, and Inventive Example 2 in Table II are The process of the present invention was used, except that no crosslinker was used. The comparative examples B and C described were carried out using the comparative process described above. [Table 2]

[0085] Addition of a 50% emulsion of Epilox in water significantly increased the viscosity of a 1% solution. At the same time, the amount of insoluble material decreases, even below the level of the non-crosslinked comparative example. [Table 3]

[0086] When used as a pure additive, the crosslinker significantly reduces the 1% viscosity of the aqueous solution. At the same time, the amount of insoluble material increased, which was probably due to the presence of some of the crosslinking agents in the reactor. The results show an irregular or uneven distribution.

Claims

1. A process for producing crosslinked cellulose ethers comprising the steps of: (i) an aqueous crosslinker emulsion comprising (ia) at least one crosslinker and (ib) water; and (ii) contacting said etherification reagent with at least one etherification agent, The aqueous crosslinker emulsion and the at least one etherification reagent are added to the activation cell. forming a reaction mixture which reacts with a cellulose material to form said crosslinked cellulose ether; process.

2. (A) (a) at least one crosslinking agent is mixed with (b) water to form an aqueous crosslinking agent emulsion. forming a (B) adding an activated cellulose material to the aqueous crosslinker emulsion of (Bi) step (A). and (Bii) contacting the compound with at least one etherification reagent. said aqueous crosslinker emulsion and said at least one etherification reagent are and reacting the crosslinked cellulose material with the cellulose ether to form a reaction mixture. The process of claim 1 .

3. The crosslinked cellulose ether is subjected to a further step of purifying, washing, drying, granulating, and milling.

3. The process of claim 1 or claim 2, comprising one or more steps.

4. The crosslinked cellulose ether is heated at a pressure of 1,000 kPa or more and at a temperature of 70° C. or more. The process of claim 1 wherein the composition is formed at a temperature of

5. The activated cellulose material comprises at least one cellulose material.

2. The process of claim 1, wherein the cation exchanger is formed by contacting the cation exchanger with an alkalizing agent.

6. The at least one cellulosic material may be selected from the group consisting of wood pulp, cotton linters, and the like. mixtures, wherein the at least one alkalizing agent is selected from the group consisting of sodium hydroxide, solutions of ammonium hydroxide, potassium hydroxide, lithium hydroxide, and mixtures thereof. The process of claim 5 , wherein

7. The concentration of the at least one alkalizing agent is adjusted to form the activated cellulose material. To achieve this, one mole of sodium hydroxide is added per mole of anhydroglucose units of said cellulosic material. From the cellulose, 3.5 moles of sodium hydroxide are obtained per mole of anhydroglucose unit of the cellulosic material.

6. The process of claim 5, wherein the metal is thorium.

8. Compressing the at least one cellulose material to form a comminuted cellulose flock material. The method further comprises forming a material, the grinding step being performed by grinding the cellulosic material into the aluminium alloy.

6. The process of claim 5, carried out prior to mixing with the calcium carbonate reagent.

9. The at least one crosslinking agent has the following chemical structure (I): 【Chemistry 1】 wherein n is 3 to 25. The process of claim 1.

10. The at least one etherification reagent is selected from the group consisting of ethylene oxide, propylene oxide, The group consisting of butylene oxide, methyl chloride, ethyl chloride, and mixtures thereof The process of claim 1 , wherein the

11. 10. The process of claim 1, wherein said contacting is carried out in an inert atmosphere.

12. The aqueous crosslinking agent emulsion is 1 / 99 to 9 / 99 by weight of the crosslinking agent and water emulsion. 9 / 1. The process of claim 1 .

13. The aqueous crosslinking agent emulsion is a crosslinker having one anhydroglucose unit of the cellulose ether. 0.0001 mole of the crosslinking agent per mole of the cellulose ether to produce anhydroglucose monomers. and the etherification reagent is present in a concentration of 0.05 moles of said crosslinking agent per mole of said crosslinking agent. From 4 moles of said etherification agent per mole of anhydroglucose unit of the cellulose ether 6 moles of said etherifying agent per mole of anhydroglucose unit of said cellulose ether The process of claim 1 , wherein the compound is present in a concentration of

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

15. A dry mortar mix comprising: (I) the crosslinked cellulose ether product of claim 14; (II) a hydrolysis binder, wherein the hydrolysis binder is a cement or gypsum material. A dry mortar mix.

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