JPH0469641B2 - - Google Patents

Description

[Detailed description of the invention]

(a) Industrial Application Field The present invention relates to a method for producing carboxymethylcellulose alkali metal salt (hereinafter abbreviated as CMC) which has excellent salt water resistance, high degree of substitution, and high viscosity.More specifically, it relates to a method for producing CMC. The degree of substitution (the average number of substituents by carboxymethyl groups per anhydroglucose, which is a structural unit of cellulose) is This invention relates to the production of carboxymethylcellulose alkali metal salts with a high viscosity of 0.80 or higher (hereinafter abbreviated as DS). CMC is a cellulose ether produced by reacting monochloroacetic acid etc. with cellulose in the presence of an alkali, and is used as a water-soluble polymer electrolyte as a thickener, dispersion example, protective colloid agent, adhesive, muddy water additive for petroleum poling, etc. It is widely used as. (b) Conventional technology Methods for producing CMC are broadly divided into two methods: the aqueous method, which uses an aqueous medium as the reaction medium, and the solvent method, which uses an organic solvent. In comparison, alkali cellulose can be obtained with a small amount of alkali, the etherification reaction is achieved in a relatively short time, the effective utilization rate of the etherification agent is high, only a small amount of etherification agent can be used, and Viscosity CMC
Because it is easy to manufacture, it is widely used industrially. CMC currently on the market has a DS of 0.4 to 1.70.
In particular, those with a value of 0.6 to 0.80 are commercially available in large quantities. However, recently, the required functions for CMC have become more dense, and as a result, the amount of CMC used in DS0.8 to 1.70 tends to increase. Furthermore, DS1.70 ~
Ultra-high DSKMC of 2.90. is becoming commercially available. This is because by increasing the DS of CMC, salt water resistance, acid resistance, rot resistance, fluidity, etc. are generally improved. However, by increasing the DS of CMC
The amount of alkali used during CMC production increases, resulting in a significant decrease in the degree of polymerization of CMC during the reaction.
It was difficult to produce high viscosity CMC. For this reason, high DS and high viscosity CMC is often produced using linter, which generally has a higher degree of polymerization than wood pulp, as a cellulose raw material. However, not only is it still not possible to obtain CMC with a sufficiently high viscosity using linter as a raw material, but the reactivity is generally lower than that of wood pulp, so
It is sometimes difficult to obtain CMC that is satisfactory in terms of quality. Furthermore, linters are more expensive than wood pulp and are economically disadvantageous. Furthermore, conventionally, as a method for producing high-viscosity CMC, a method in which epichlorohydrin is applied during the CMC production process is known (Koichiro Watanabe, Industrial Chemistry Magazine, Vol. 68, p. 1923, 1965). According to the above-mentioned literature, the mechanism of action of epichlorohydrin is thought to be that in the presence of an alkali, it reacts with the hydroxyl groups of cellulose in the following manner to create a crosslinked structure, thereby increasing its viscosity. At the time this report was made, it attracted attention as a method for producing high-viscosity CMC, and many attempts were made to apply it. However, although it has a high viscosity, its resistance to salt water is extremely poor, so its industrial application has hardly been made. This was manufactured industrially at the time (1965)
Since most of the CMCs were low DSCMCs with a DS of 0.50 to 0.70, they were cross-linked with epichlorohydrin.
It is thought that this is because CMC hardly dissolves in water containing salt such as common salt because dissociation of carboxyl groups is extremely suppressed. (c) Purpose of the Invention The present invention was made under the above circumstances, and it is an object of the present invention to provide a carboxymethyl cellulose alkali metal salt having high DC, high viscosity, and good salt water resistance. (d) Structure of the Invention This invention provides a method for reacting a cellulosic raw material with (A) an inorganic alkali metal compound in a water-containing organic solvent, and then reacting with an etherification agent, or (B) adding an etherification agent. The cellulosic raw material is impregnated and then the inorganic alkali metal compound is added to allow the reaction to proceed, and during this step (A) or (B), epichlorohydrin is added during or after the reaction with the inorganic alkali metal compound is completed. Provided is a method for producing a carboxymethyl cellulose alkali metal salt, which is characterized by reacting to obtain a carboxymethyl cellulose alkali metal salt having a degree of carboxymethyl substitution of 0.80 or more, excellent salt water resistance, and high viscosity. According to the method, a carboxymethylcellulose alkali metal salt having a DS of 0.8 or more can be obtained. The cellulosic raw materials used in this invention are those commonly used in CMC production.
Wood pulp or linters may be mentioned. In this invention, the water-containing organic solvent used as the reaction medium includes ethyl alcohol, isopropyl alcohol (hereinafter abbreviated as IPM),
- Organic solvents such as propyl alcohol, tert-butyl alcohol, isobutyl alcohol, n-butyl alcohol, acetone and oxane, as well as ethyl alcohol-benzene, ethyl alcohol-toluene, ethyl alcohol-n-hexane,
IPA-benzene, IPA-toluene and IPA-n-
Examples include a mixture of a mixed organic solvent such as hexane, and water. The amount of the water-containing organic solvent used is usually 1 to 30 times the weight of the cellulosic raw material. The inorganic alkali metal compound in this invention is
Any material that forms alkali cellulose may be used. Specific examples thereof include sodium hydroxide, potassium hydroxide, lithium hydroxide, rubidium hydroxide, and cesium hydroxide. but,
It is not particularly limited to these. Sodium hydroxide is the most advantageous because it is inexpensive. Note that the CMC produced by the method of this invention becomes a salt of the alkali used. Therefore, if sodium hydroxide is used, CMC becomes the sodium salt. The etherification agent of this invention is a reagent capable of introducing a carboxymethyl group. Specific examples include monochloroacetic acid, its alkali metal salts, or its ester derivatives such as methyl, ethyl or isopropyl esters. In the method of this invention, the reaction with epichlorohydrin is carried out at a stage when at least a portion of alkali cellulose or CMC has been produced. To produce alkali cellulose or CMC, a cellulosic raw material is reacted with (A) an inorganic alkali metal compound and then an etherification agent in a water-containing organic solvent, or (B) an etherification agent is added. Then, an inorganic alkali metal compound is added and reacted, or (A) and (B) are mentioned. Method (A) essentially involves reacting a cellulosic raw material with an inorganic alkali metal compound (hereinafter referred to as alkali) to form alkali cellulose, and converting this alkali cellulose into CMC using an etherification agent. At that time, the etherification agent may be reacted in a state where all of the cellulosic raw material is not converted into alkali cellulose, and the reaction may be further carried out by adding a required amount of alkali. In method (B), a cellulosic raw material is impregnated in advance with the entire required amount of etherification agent, and an alkali is added thereto to allow the reaction to proceed. The alkaline charge is used in an amount necessary to convert the cellulosic raw material into alkali cellulose. On the other hand, in the present invention, it is desirable to control the molar ratio of alkali and etherification agent used in the etherification step. The alkali is added to the etherification agent in a molar ratio of 1.00 or more.
It is usually preferable to keep it at 1.00 to 1.30 mol. In addition, here, "alkali" and "etherification agent"
The molar ratio is expressed as (number of moles of alkali charged) - (number of moles of alkali neutralized by the etherification agent)/(number of moles of etherification agent charged). If the amount of alkali present in the reaction system is large, it will not only promote side reactions of sodium monochloroacetate, which is an etherification agent, as shown in the following formula, but also reduce the effective utilization rate of the expensive etherification agent. The result is that the CMC of the DS cannot be obtained. ClCH ₂ COONa + NaOH → CH ₂ (OH) COONa + NaCl On the other hand, when trying to produce CMC with a high DS with the aim of improving the salt water resistance of CMC, etc., the amount of etherification agent to be charged will naturally increase. As a result, the amount of alkali used inevitably increases. On the other hand, it is preferable that the etherification agent is present in excess at the beginning of the etherification step. Specifically, it is preferable that the alkali be present in a molar ratio of 0.10 to 0.99 to the etherifying agent. Then, in order to prevent the reaction system from becoming acidic due to the consumption of alkali as the etherification reaction progresses, it is desirable that the etherification reaction is carried out by further adding an alkali to achieve a final molar ratio of 1.00 or more. By this,
A relatively high CMC of DS can be obtained. This method of adjusting the amount of alkali added constitutes one of the features of the present invention. When the DS is low, a method in which the alkali is present in excess of the etherifying agent, that is, in a molar ratio of 1.0 to 1.3 from the beginning, is sufficient. This has the advantage of simple operation and short reaction time. In addition, since the amount of alkali used increases, the upper limit of the DS obtained in one reaction operation is approximately 1.7 if the required amount of alkali is added from the beginning, and approximately 2,000 DS if the required amount of alkali is initially added. 2 is the upper limit. When obtaining the object of this invention having a high DS of DS1.50 or more, especially DS1.80 or more, a high DS of
It is preferable to use a method in which CMC is produced in advance and reacted with epichlorohydrin without isolation. Such cases are also included in the method of the present invention. Note that the step of preparing alkali cellulose by applying an alkali to the cellulosic raw material and the step of adding and mixing an etherifying agent such as monochloroacetic acid are performed by stirring and mixing at 10 to 40° C. for about 10 to 180 minutes. On the other hand, the etherification reaction is 30-240 at 50-80℃.
It is appropriate to do this for a minute. Next, in the method of the present invention, epichlorohydrin is added and reacted at the stage when at least alkali cellulose or CMC is produced from the cellulosic raw material. Since the epichlorohydrin to be added is a liquid at room temperature, it may be added as is in small amounts, but it is preferable to dilute it with an organic solvent used as a reaction solvent and then add it. In addition, as mentioned above, the action mechanism of epichlorohydrin is thought to be that it reacts with the hydroxyl groups of cellulose or CMC in the presence of alkali and cross-links between or within molecules, so if the system is alkaline, it can be added at any stage. However, considering the uniformity of crosslinking and the effective utilization rate of epichlorohydrin, it is possible to use ether in the alkali cellulose preparation process before the etherification reaction, where the amount of alkali in the system is large and the temperature is kept low, or in the presence of an alkali. It is preferable to add the curing agent prior to or during the step of adding and mixing it. Although it seems to work for a short time, it is preferable to keep it for about 10 minutes or more. In addition, the amount added depends on the type and type of cellulosic raw material used, the type and amount of reaction solvent used, and the manufacturing process.
Although it varies depending on the timing of CMC DS addition, etc., it is about 0.05 to 4.0% based on the weight of cellulosic raw material.
Preferably it is added in an amount of 0.1 to 2.0%. That is, when it is less than 0.05, almost no thickening effect is observed, and when it exceeds 4%, it becomes partially water insoluble, resulting in poor salt water resistance. By adopting the manufacturing method of the present invention as described above, it is possible to manufacture high DS and high viscosity CMC, which was conventionally used as a raw material for expensive linters, by using inexpensive wood pulp as a raw material, which has the advantage Not only that, but it also makes it possible to produce CMC with high DS and high viscosity, which was previously impossible to produce using linter as a raw material. Furthermore, by appropriately adjusting the amount of epichlorohydrin added, it is possible to not only adjust the viscosity of the produced CMC but also its flow behavior. That is, by increasing the amount of epichlorohydrin added and increasing the degree of crosslinking, it is possible to change the fluidity of a high DSCMC aqueous solution, which had a flow behavior close to Newtonian flow, to a fluidity with high thixotropy. From the above, the CMC produced by the method of the present invention is not only useful as a mud water additive for petroleum drilling, a mud water additive for civil engineering boring, etc. used in the presence of seawater or salt water, but also as a salt, etc. It is useful in many applications, such as applications where it is used in the coexistence of salts of Examples and comparative examples specifically explaining the present invention will be shown below, but the present invention is not limited to these examples. In addition, the properties of the generated CMC are (1) degree of substitution (DS),
The measurement and evaluation methods for (2) viscosity, (3) salt water resistance, and (4) etherification agent effective utilization rate (AM) are as follows. (1) Degree of substitution (DS) Precisely weigh 1.0 g of CMC, put it in a magnetic platinum crucible and incinerate it at 600℃, and convert the sodium oxide produced by the ashing to phenolphthalein with N/10H ₂ SO ₄ . was titrated as an indicator, and the titration amount Aml was entered into the following formula to calculate the DS. DS=162×A×f/10000−80+A×f where f is the titer of N/10H ₂ SO ₄ . (2) Viscosity measurement method: Pour 2.5 g of CMC into a cylindrical glass container with a diameter of 55 mm and a depth of 125 mm and add pure water or 4% saline solution.
Charge and dissolve CMC to a concentration of 1.0% (by weight). Next, after adjusting the temperature to 25℃, the rotor was measured using a BL type viscometer (manufactured by Tokyo Keiki Co., Ltd.).
After rotating at 60 rpm for 1 minute, the numerical value was read and multiplied by a predetermined constant to determine the viscosity. Units
Expressed in CP (centipoise). (3) Salt water resistance Salt water resistance was evaluated by the viscosity ratio calculated using the following formula. Viscosity ratio=(CMC1% viscosity in 4% saline solution)/(CMC1% viscosity in pure solution) It was evaluated that the larger this viscosity ratio was, the better the saltwater resistance was. (4) Etherification agent effective utilization rate (AM) Calculated using the following formula. AM = DS of produced CMC / number of moles per anhydroglucose unit of cellulose of charged etherification agent x 100% Note that parts in Examples and Comparative Examples refer to parts by weight,
% indicates weight %. (e) Examples Example 1 760 parts of isopropyl alcohol (hereinafter abbreviated as IPA) and sodium hydroxide (purity 98.0%) were placed in a No. 5 Werner-type kneader with two-shaft stirring blades.
Add 141.6 parts by dissolving 140.0 parts of pure water, cool the jacket to 10-15°C by passing cold water through the jacket, and remove air by purging with nitrogen gas several times. Next, 200 parts of powdered wood pulp with a moisture content of 6% and a degree of polymerization of 750 is added, and alkali cellulose is prepared by stirring and mixing at 12 to 20°C for 120 minutes after purging with nitrogen gas several times to remove air. . During the preparation of the alkali cellulose (after 60 minutes), 1.0 part of epichlorohydrin was dissolved in 100 parts of IPA and added. Next, 162.4g of monochloroacetic acid (98.5% purity)
Dissolve it in 162.4g of IPA and add it little by little.
Stirring and fitting are carried out at 70°C for 30 minutes, then warm water is passed through the jacket to raise the temperature to 70°C, and the etherification reaction is carried out at 70°C for 120 minutes. Excess sodium hydroxide is then neutralized with acetic acid and cooled to room temperature by passing cold water through the jacket. Next, the reaction mixture is taken out from the kneader and centrifuged to remove the IPA aqueous solution. Next, the product was washed three times with 75% methyl alcohol aqueous solution 4 to remove by-products such as salt, and then dried at 80 to 110°C for 4 hours to obtain the CMC of the present invention. The results are summarized in Table 1. Examples 2 to 5 and Comparative Examples 1 to 4 Examples were conducted under exactly the same conditions and method as in Example 1, except that the amounts of sodium hydroxide and monochloroacetic acid used and the amount of epichlordrin added were different. 2 and 5 and Comparative Examples 1 to 4. The results are summarized in Table 1. Example 6 675.1 parts of IPA was charged into a No. 5 Werner type kneader with two-shaft stirring blades, and 158.0 parts of sodium hydroxide (98% pure) was dissolved in 158.0 parts of pure water and heated at 12 to 20°C. After cooling to 6% moisture, degree of polymerization
Adding 200 parts of 750 powdered wood pulp;
Purge with nitrogen gas several times to remove air and heat to 12-20℃
Mix and stir for 120 minutes to prepare alkali cellulose. During this alkaline cellulose preparation (after 60 minutes) add 1.0 part of epichlorohydrin.
It was dissolved in 100 parts of IPA and added. Next, 244.9 parts of monochrome acetic acid (purity 98%) was dissolved in 244.9 parts of IPA, added while cooling, and stirred and mixed at 12 to 25°C for 30 minutes. After that, the temperature was raised to 60℃ in about 10 minutes and the temperature was increased to 60℃.
Perform the etherification reaction for minutes. Next, 54.3 parts of sodium hydroxide was dissolved in 36.2 parts of pure water and added.
After stirring and mixing at 70℃ for 15 minutes, the temperature at 70℃ was increased to 90℃.
Perform the etherification reaction for minutes. Thereafter, the slight remaining sodium hydroxide is neutralized with acetic acid. The subsequent operations were carried out under exactly the same conditions and method as in Example 1 to obtain the CMC of the present invention. those results first
It is summarized in the table. Example 7 Instead of the powdered wood pulp of Example 6,
CMC of the present invention was obtained under the same conditions and method as in Example 6, except that 359.4 parts of powdered CMC (188.0 parts in terms of cellulose) was used.DS1.54 Pure water 1% Viscosity 340cp Water 7% Purity 99%. The results are summarized in Table 1. Comparative Examples 5 and 6 Comparative Example 5 was carried out using the same method and conditions as Example 6 without adding epichlorohydrin, and Comparative Example 5 was carried out using the same conditions and method as Example 7 without adding epichlorohydrin. 6
And so. The results are summarized in Table 1. Comparative Example 7 Using 200 parts of linter (moisture 6%, degree of polymerization 2100) in place of the powdered wood pulp of Example 6,
Comparative Example 7 was carried out under the same conditions and method as in Example 6 without adding epichlorohydrin.
And so. The results are summarized in Table 1.

[Table] As is clear from Table 1, the CMC of the example manufactured by the manufacturing method of this invention was manufactured by the conventional method.
Compared to CMC, it has a much higher viscosity and superior salt water resistance. In addition, among the production methods of this invention, method b (Example 6) has a higher DS and higher viscosity than method a (Example 3), even though the amount of etherification agent charged is the same. It is. In other words, when manufacturing high DS products, it is found that it is better to react by dividing the alkali as in method b.

Claims (1)

[Scope of Claims] 1 Cellulosic raw material is prepared by (A) reacting an inorganic alkali metal compound with a cellulosic raw material in a water-containing organic solvent and then reacting with an etherifying agent, or (B) adding an etherifying agent to produce a cellulosic raw material. Then, an inorganic alkali metal compound is added to allow the reaction to proceed, and during this step (A) or (B), epichlorohydrin is reacted while the reaction with the inorganic alkali metal compound is in progress or after completion. A process for producing a carboxymethyl cellulose alkali metal salt, which is characterized in that it has a carboxymethyl cellulose alkali metal salt having a degree of carboxymethyl substitution of 0.80 or more, excellent salt water resistance, and high viscosity. 2. The inorganic alkali metal compound is initially added to the etherification agent at a molar ratio of 0.10 to 0.99, and then added to the etherification agent at a molar ratio of 1.00 or more to allow the reaction to proceed. A manufacturing method according to claim 1. 3. The manufacturing method according to claim 1 or 2, wherein the cellulosic raw material is wood pulp or linter. 4. The production method according to any one of claims 1 to 3, wherein the etherification agent is monohalogenoacetic acid, or an alkali metal salt or lower alkyl ester thereof. 5. The manufacturing method according to any one of claims 1 to 4, wherein the inorganic alkali metal compound is sodium hydroxide, potassium hydroxide, lithium hydroxide, rubidium hydroxide, or cesium hydroxide. 6 The water-containing organic solvent is ethanol, n-propanol, isopropanol, n-butanol, t-butanol, isobutanol, acetone, dioxane, benzene, toluene or n-hexane,
The manufacturing method according to any one of claims 1 to 5, wherein the organic solvent is a mixture of water and an organic solvent consisting of a mixture thereof. 7. The production according to any one of claims 1 to 6, wherein the intermediate carboxymethylcellulose alkali metal salt produced after reacting the etherification agent has a degree of carboxymethyl group substitution of 1.00 or more. Law. 8 The target carboxymethylcellulose alkali metal salt has a carboxymethyl group substitution degree of 0.80 to
3.0 Claims 1 to 7
The manufacturing method described in any one of paragraphs.