FI100974B - Process for the preparation of sodium carboxymethylcellulose - Google Patents

Description

100974

METHOD FOR THE PREPARATION OF SODIUM CARBOXYMETHYL CELLULOSE

This invention relates to a process for preparing sodium carboxyacetylcellulose.

The invention is characterized by what is stated in claim 1.

As is well known, the karhoks imi style of cellulose (hereinafter abbreviated as CMC) has long been manufactured industrially and has been applied to many uses, such as as a paste or thickener.

CMC is used in most cases as an aqueous solution and therefore problems arise due to, for example, its form, its sensitivity to enzymatic degradation and the marked decrease in solution viscosity by the action of a salt such as sodium chloride. In addition, there have been problems such as strong thixotropy and clear changes in its solution viscosity over time, so improvements in its various applications have long been expected.

The present inventors have concluded that the distribution of the carboxymethyl group must be limited to a certain period in order to solve the above-mentioned problems, in particular to solve problems in aqueous solution behavior, more specifically to solve solution behavior problems such as viscosity reduction and salt presence.

In the present invention, the distribution of the carboxymethyl group is expressed as a mobility distribution due to its actual measurement method, which is described below.

2 100974

Terashima et al., In the Polymer Journal, vol. 8, p.

449- ^ 55 (1976) that the charge density distribution of a polyelectrolyte, for example the distribution of the degree of substitution of CMC, can be measured electrophoretically.

The following is a brief description of the figures:

The diagram in Figure 1 shows the relationship between transition time and mobility.

The diagram in Figure 2 schematically shows the changes in the state of the electrophoretic boundary as a refractive index.

The graph in Figure 3 shows the relationship between the different mobility distributions of CMC and the degrees of substitution of the average carboxymethyl groups.

The graph in Figure 4 shows the relationship between the average degree of substitution and median mobility.

In the present invention, the degree of substitution depends on a mobility distribution that can be measured electrophoretically, wherein this mobility distribution is determined by the following measurement method.

Electrophoretic measurement of the DS distribution is carried out at 25 ° ± 0,1 ° C using a Tsukasa-Tiselius electrophoresis apparatus and a Schlieren optical system, using the following conditions: sample concentration 0,2 g / 100 ml solvent 0,1 N aqueous NaCl solution

electric current 2 mA

When electrophoresis is performed under these conditions, the electrophoretic mobility U can be determined experimentally using the following equation: 3 100974 U = K x A x h, where i t K = specific electrical conductivity of the solution 1,067x 10 ~ 2 / cm A = cell cross-sectional area 0.351 cm2

i = transient electric current 0.002 A

h = transition distance X cm t = transition time

Figure 2 schematically depicts the state of the limit obtained by electrophoresis by means of the change (An) of the refractive index (DS = 0.73, after 7 hours); where A is the maximum mobility, B is the minimum mobility, and C is the median mobility corresponding to the corresponding transition times. For the sake of convenience, the present invention measures the displacement and movements of the rising boundary, i.e. the abscissa points A, B and C, corresponding to the inverse of the time taken to reach the lines of Figure 1 (DS = 0.73, 1% viscosity 210 cP). Extrapolation to infinity gives the motions IV, Ug * and Uq1 · tv - Ug ’is defined as the mobility distribution (AU).

Figure 11 shows the dependence between Uc 'and mean DS as measured by standard chemical measurement. As shown in this figure, Au represents the width of the DS distribution (ADS), i.e., the difference between the maximum and minimum DS of a CMC sample.

On the other hand, the solution behavior of CMC aqueous solution corresponds to brine resistance and thixotropy, but due to the heterogeneity of the reaction or the lack of absoluteness of the reaction, there is essentially an anhydroglucose unit without any carboxymethyl moiety.

When CMC has a more uniform DS distribution, it has a larger 4 Ί CC 97 4 amount of soluble moiety with the same average DS, so the repulsive forces of the soluble moiety decrease to a lesser extent when salt, e.g., sodium chloride, is added to aqueous solution and increases as shear stress is reduced and, conversely that is, the rate of development of thixotropy decreases as the external force disappears. Thus, the stability of a solution based on the balance between the repulsive force of the soluble moieties and the cohesive force of the sparingly soluble moieties depends on the DS distribution because a CMC with a higher average DS or a higher amount of soluble moiety has greater stability when in solution. Similarly, CMC having an average DS greater than 2.0 has a stable solution state regardless of its production process because it has a soluble moiety that is formed with at least one carboxymethyl group as a substituent on almost every anhydroglucose unit. CMC with a mean DS of less than about 0.5 has a substantially unstable solution state due to the fact that half of the anhydroglucose units have no substituents, no matter how evenly substituted with carboxymethyl groups. Especially when the DS is less than about 0.3, the CMC becomes water insoluble. However, CMC with greater uniformity has a more stable solution state in these cases as well. Therefore, it is an object of the present invention to improve the solution state of a CMC having an average DS between • * ·. ”·! 0.4 - 1.6.

The present inventors have measured solution state stability, denoted by ^ u, or ^ DS, as well as salinity resistance, including enzyme resistance, and commercial resistance. available CMCs as well as CMCs produced by various production processes (including processes according to a prior application by the applicant of this invention). The results are shown in Table 2.

5 100974 These results are illustrated by the diagram in Figure 3, which shows the relationship between AU and log (DS), in which closed and open circles are separated as follows.

Accordingly, closed circles represent those CMC products with a mean DS greater than 0.7 and a brine resistance of less than 0.9, while open circles represent those with a brine resistance of 0.9 or greater. If the saline resistance values of CMC products with a mean DS are almost the same assume that they have a salt resistance directly proportional to the AU, then the following formula (as above) represents the line obtained by combining the points the brine resistance value is 0.9: AU x 105 = -3.0 log (DS) + 3.20;

When this line is extrapolated to a point with a mean DS of less than 0.7, the line forms the boundary between CMC products with (relatively) good and (relatively) poor brine resistance, and the relative values also indicate products with the same average DS, the comparability of enzyme resistance, with the line indicating the limit beyond which enzyme resistance nearly doubles. It has been found that the above line forms a boundary, also between known CMC products and unknown CMC products, i.e. those made by the processes described in Japanese Patent Application Nos. 50277/1981 and 142731/1981, which are incorporated herein by reference. prior applications of the applicant of the invention.

The novel CMC of this invention has a more even substituent distribution than conventional or commercially available products, such as those prepared using ordinary monochloroacetic acid as the ether former, and is therefore characterized by, for example, 6,100,974 distinctly excellent salt water resistance, a property that is of great practical importance in CMC applications such as oil drilling mud.

It is well known that the viscosity of CMC is significantly reduced in an aqueous solution with a strong electrolyte such as sodium chloride compared to the case where CMC is in pure solution because CMC is a polyelectrolyte, its dissociation in such an aqueous solution is reduced, which is a major disadvantage in applications where it is dissolved in an aqueous solution containing salt, such as oil drilling in applications.

However, as shown in the following examples, the CMC of the present invention has such excellent resistance to brine that it hardly has a decrease in viscosity, but rather its viscosity increases even when dissolved in a solution of $ 4 sodium chloride compared to the case where it is dissolved in plain water.

In addition, the CMC of the present invention has uniformly introduced substituents so that the amount of its insoluble matter and semi-dissolved swollen gel is lower and its transparency is excellent compared with those produced by a conventional process, and the fabric is still less clogged when used as a textile printing paste. In addition, the resistance of this CMC enzymes (rot resistance) is excellent, which is a property of great practical importance for various applications such as earthmoving, oil drilling, mud explosives, lactic acid beverages, toothpastes, Textile printing pastes, water-based pastes.

While the processes for the CMC of the present invention have been illustrated as described above, the present inventors disclosed a process 7 100974 for preparing a CMC having excellent brine resistance as described above, comprising an ether-forming agent prepared by esterification with a monochloro acetic alcohol with isopropyl alcohol (Japanese Patent Application No. 50277/1981), and a process for preparing an alkali salt of carboxymethylcellulose ether by reacting the cellulose substance with an ether-forming agent in an aqueous organic solvent system in the presence of an alkali, the process being characterized by the ether-forming reaction is initiated in a system in which the amount of ether-forming agent is so much greater than necessary that the alkali is present in a molar ratio of (alkali) / (ether-forming agent) greater than 0.10 to 0.99, and then the ether-forming reaction is carried out by adding alkali in portions. alkali) / (ether-forming agent) in the last stage is more than 1.00 (Finnish patent application No. 822987), where (alkali) / (ether-forming agent) = ;;. t: molar number of alkali fed to the etherification agent i · molar number of neutralized alkali fed to the etherification agent molar number • ·: 1 · · The CMCs obtained by these processes have a very uniform • ·: 1 · 1: distribution of carboxymethyl groups so that their mobility in the distribution (^ U) is very low by electrophoresis • »• measured, forming a new CMC according to the present invention.

♦ · • · »• · ♦ * r According to these processes, it is possible to obtain CMC products for which the uniformity of the DS distribution, expressed in terms of AU, is limited by a value represented by the following formula:

Δϋ X 105 <(-3.0 log DS + 3.20) cm2 / sV

8 100974

On the other hand, although its lower limit is not specifically defined, it is usually represented by the following formula:

Δϋ x 105> (-2.0 logDS + 2.0) cm 2 / s V

Examples of the syntheses of the CMC samples and comparative CMC samples of this invention are set forth below.

Here are parts by weight and percentages by weight.

Sample A (this invention, according to Japanese Patent Application No. 50277/1981): 651.2 parts of isopropyl alcohol (100% purity, hereinafter abbreviated as ΊΡΑ ') were charged to a five-liter double-impeller reactor, followed by 96.0 parts of sodium hydroxide (98 JS purity) dissolved in 1 to 3.0 parts of deionized water, the mixture was cooled to 20 ° C and a further 200 parts of ground cellulose (95% purity, average degree of polymerization 850) was added. The contents were stirred at 20-30 ° C for 60 minutes to obtain alkali cellulose. 87.6 parts of isopropyl monochloroacetate (99 μm purity) were then diluted and 56.3 parts of isopropyl acetate (99% purity) were diluted with 95.8 parts of IPA and added to neutralize the excess sodium hydroxide. The resulting mixture was stirred at 20-30 ° C for 30 minutes. The temperature was then raised to 70 ° C, and the mixture was stirred for 2 hours to enhance the ether formation reaction, after which the excess sodium hydroxide was neutralized with acetic acid.

After the reaction, the reaction mixture was removed from the reactor, centrifuged to remove ipa as the reaction solution, washed twice with 1000 parts of 75% aqueous methyl alcohol to remove by-products of sodium chloride and sodium glycolate, and then centrifuged to remove aqueous methyl alcohol.

100974 9

The purified product was dried in a dryer at 80-100 ° C for about 4 hours to obtain 255 parts of the CMC of this invention.

Samples B-P were obtained by performing the reaction and purification under the same conditions as in Sample A, except that the species and amounts of cellulosic material, sodium hydroxide, and etherifying agent were varied according to Table 1. Samples B-E are CMC products of the present invention and Sample F is a CMC according to a comparative example.

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to remove the sodium chloride, sodium glycolate and sodium acetate formed as products, and then the mixture was centrifuged i * ·; to remove aqueous methyl alcohol. The purified product was dried in a dryer at 80-100 ° C for about 6 hours to achieve the CMC of this invention.

· * • · • «· * ... For CMC products according to Table 2, measurements were made of the average degree of substitution (DS), the average degree of polymerization (P), the mobility distribution (^ U ), brine resistance. ability and enzyme resistance. Table 2 contains

* .. · the above-mentioned samples A-E of the present invention, sample Q

* ’And reference sample F and commercially available products G, H, I, J, K, L, M, N and P. The results are shown in Table 2.

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Note: 1. CMC samples G-N, P and R-U are commercially available.

Among them, M is a product prepared in a process using an aqueous medium, and the others are obtained from processes using another solvent. Each of the above samples is available as follows: G: Daicel Chemical Industries, Ltd. Grade No. 1130.

H: Daicel Chemical Industries, ltd Grade No. 1150.

I: Celai WSA by Daiichi Kogyo Seiyaku K.K.

J: Celai EP by Daiichi Kogyo Seiyaku K.K., suitable for oil drilling.

Q: Daicel Chemical Industries, Ltd. grade No. 2200H, suitable for oil drilling.

L: Quality No. 1860 of Daicel Chemical Industries, Ltd, suitable as a printing paste for textiles

M: Adachi Koryo K.K.'s Cellucol M

N: Sanyo Kokusaku Pulp K.K. quality no. PN05L, which is suitable as a printing paste for textiles.

P: Daiichi Kogyo Seiyaku K.K. grade No. SP-150, which is suitable as a printing paste for textiles.

R: Cekol MVE from Swedish Uddeholm.

S: Tylose C-1000p from West German Hoechst.

T: Finnish Forest Association's Pinnfix 700E

100974 14 U: Carbocel AG / LA of Lamberti, Italy.

(1) The measurement and evaluation of the degree of substitution (DS), (2) the resistance of brine, and (3) the resistance of the enzymes shown in Table 2 were performed as follows.

(1) Degree of substitution (DS) 1 g of CMC was accurately weighed, placed in a platinum or porcelain crucible and incinerated at 600 ° C. Sodium oxide formed during incineration was titrated with N / 10 sulfuric acid using phenolphthalein as indicator. DS was determined by fitting the amount of acid added (A ml) to the following equation.

DS = _162 x A x f_ 10 000 - 80 x A x f f = N / 10 sulfuric acid factor (2) Resistance of brine

The resistance of brine was evaluated by the viscosity ratio represented by the formula below. Viscosity was measured with a BL viscometer on rotor 4, using 60 rpm and a temperature of 25 ° C.

The viscosity of the aqueous solution in NaCl at 4%. 1 weight - # CMC viscosity (cP) _. ,: ratio of 1 weight in pure water - $ CMC viscosity (cP)

The higher the viscosity ratio, the better the resistance of brine.

(3) Resistance to enzymes

To an aqueous solution of 1 # CMC was added cellulase 5 mg / g CMC (Cellulase-AP, a product of Amano Pharmaceutical Co., Ltd. 100,974), and the solution was hydrolyzed at room temperature for 140-1 ^ 5 hours (hydrolysis was essentially completed in 140 hours). The glucose formed as a hydrolyzate was then measured by the glucose oxidation method. The lower the amount of glucose produced, the higher the resistance of CMC enzymes is considered.

The enzyme resistance values shown in this Table 2 represent the amount of glucose formed, expressed as 1000 anhydroglucose units (amount / 1,000 AGU).

Claims (3)

100974 PATENT CLAIM A process for preparing sodium carboxymethylcellulose having an average degree of substitution (DS) of carboxylmethyl groups per anhydroglucose unit and a degree of polymerization of between 100 and 1500 from cellulose, sodium hydroxide and an etherifying agent by reacting cellulose with sodium hydroxide in the presence of isopropanol, and the alkali cellulose formed is etherified using an etherifying agent prepared by essentially esterifying all of the monochloroacetic acid with isopropyl alcohol, characterized in that the mobility distribution (AU) of the prepared sodium carboxymethylcellulose measured by electrophoresis + 3.20) cm 2 / sV. 1. A compound for the preparation of sodium carboxymethylcellulose, the carboxymethyl group having a genomic substitution rate (DS). . per anhydroglucose as a ligand with 0.4 to 1.08 and polymerization; tionsgradens numerisk genomsnittsvärde är mellan 100 - 1500, frän Cellulosa, natriumhydroxid och eteriseringsämne, i vilket för- *. The cellulose is reacted with sodium hydroxide in the presence of water and isopropanol, and in the presence of ether-cellulosic ether. Sodium carboxymethylcellulose mobility suppression (AU) is mediated by electrophoresis and is represented by the following formulas: • · · * • ·:. * ·· AU 105 <(-3.0 log DS + 3.20) cm2 / sV. i »t * * * I I • I I t i <I (