KR20170076937A

KR20170076937A - Method of manufacturing hydroxyalkyl cellulose and hydroxyalkyl cellulose manufactured by the method

Info

Publication number: KR20170076937A
Application number: KR1020150186623A
Authority: KR
Inventors: 장용성; 이준수; 장현택
Original assignee: 롯데정밀화학 주식회사
Priority date: 2015-12-24
Filing date: 2015-12-24
Publication date: 2017-07-05

Abstract

(1) reacting cellulose with an alkalizing agent to obtain an alkalized cellulose; (2) reacting the alkalized cellulose with an etherifying agent to obtain hydroxyalkylcellulose; (3) reacting the hydroxyalkylcellulose with a crosslinking agent; And (4) washing the hydroxyalkylcellulose reacted with the cross-linking agent with water to remove impurities. The present invention also relates to a hydroxyalkylcellulose produced by the method and a method for producing the hydroxyalkylcellulose. According to the method for producing a hydroxyalkylcellulose of the present invention, the step of reacting the hydroxyalkylcellulose with the crosslinking agent can delay the time for dissolving the hydroxyalkylcellulose in water, and therefore, The washing process for removing impurities from the alkyl cellulose can be carried out. As a result, the hydroxyalkyl cellulose having improved chromaticity can be provided by an economical and easy method.

Description

[0001] The present invention relates to a method for producing hydroxyalkylcellulose and a method for producing the hydroxyalkylcellulose,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process for producing hydroxyalkylcellulose and a hydroxyalkylcellulose prepared by the process, and more particularly to a process for producing hydroxyalkylcellulose by reacting hydroxyalkylcellulose with a crosslinking agent, To a process for producing cellulose and to a hydroxyalkyl cellulose having improved chromaticity produced by the process.

Cellulose ether refers to a cellulose derivative obtained by etherifying a hydroxy group of cellulose, and is industrially very useful compound used in a wide range of fields such as pharmaceuticals, foods, cosmetics, building materials and daily necessities. Such cellulose ethers include alkylcellulose, hydroxyalkylcellulose, hydroxyalkylalkylcellulose and the like.

As a method for producing such a cellulose ether, there is known a method in which an alkaline solution is contacted with a pulp purified with high purity to prepare an alkaline cellulose, and the alkalized cellulose is reacted with an etherifying agent. The cellulose ether prepared by the above method is then subjected to a washing process for removing impurities. If residual impurities remain in the process, the chromaticity and transparency of the cellulose ether adversely affect the cellulosic ether. However, when the cellulose ether is applied to household products such as shampoos for infants, transparency and chromaticity of the cellulose ether are reflected in transparency and chromaticity of the final product. Therefore, it is important to prevent impurities from remaining in the etherified cellulose ether.

Conventionally, as a method for removing impurities, there has been used a method of washing the reaction product with water or other mixed solvent after the etherification reaction of the alkalized cellulose.

For example, Patent Document 1 (Korean Patent Laid-Open No. 10-2010-0118802) describes a method of cleaning impurities produced during the hydroxyethylmethylcellulose synthesis process using boiling water as a production example. Specifically, according to Patent Document 1, an alkoxylated cellulose is reacted with an etherifying agent to prepare a hydroxyethyl methylcellulose slurry, and then the slurry is washed twice with boiling water to remove impurities such as salts.

Since cellulose ethers belonging to hydroxyalkyl alkylcellulose such as hydroxyethylmethylcellulose do not dissolve in hot water, impurities can be removed by the same method as described above. In the case of hydroxyalkylcellulose, however, water is soluble in hot water, A method of washing using a mixture of water and an organic solvent has been used.

For example, in an example of producing hydroxyethylcellulose in Patent Document 2 (Japanese Patent Laid-Open No. 10-2014-0075503), ethylene oxide is added to alkalinized cellulose to react and neutralized, and then 80%, 85% %, 92%, 97% concentration of acetone / water in a mixed solvent of 2000 ml. In this case, there are disadvantages in that a complicated facility is required because a plurality of stages of centrifugal separators and slurry tanks are normally connected in series to remove impurities generated in the synthesis.

Therefore, there is a need for research on a method for producing hydroxyalkylcellulose which can remove impurities using only water without complicated facilities such as a multi-stage centrifugal separator.

KR 1020100118802 A KR 1020140075503 A

The present invention provides a method for producing a hydroxyalkyl cellulose having a delayed time dissolved in water by reacting a hydroxyalkyl cellulose with a crosslinking agent.

The present invention provides a hydroxyalkylcellulose which can remove impurities by using water alone in the washing process, thereby improving chromaticity.

In order to solve the above-described problems, the present invention provides a method for producing cellulose fibers, comprising the steps of: (1) reacting cellulose with an alkalizing agent to obtain an alkalized cellulose; (2) reacting the alkalized cellulose with an etherifying agent to obtain hydroxyalkylcellulose; (3) reacting the hydroxyalkylcellulose with a crosslinking agent; And (4) washing the hydroxyalkylcellulose reacted with the cross-linking agent with water to remove impurities. The present invention also provides a method for producing hydroxyalkylcellulose.

The step (3) is preferably carried out in a pH range of 2 to 6, and the pH may be controlled by any one or two or more acids selected from the group consisting of nitric acid, acetic acid and hydrochloric acid.

The step (3) is preferably carried out at a reaction temperature of 65 to 85 ° C for 10 to 30 minutes.

The crosslinking agent may be selected from the group consisting of glutaraldehyde, glyoxal, malondialdehyde, succindialdehyde, terephthalaldehyde, formadehyde, acetaldehyde, propionaldehyde, and one or more selected from the group consisting of propionaldehyde, butyraldehyde, benzaldehyde, cinnamaldehyde, 4-methylbenzaldehyde and furfural. And the throughput of the crosslinking agent is preferably 2 to 18 parts by weight based on 100 parts by weight of the hydroxyalkylcellulose.

The production method according to the present invention may further comprise, between step (2) and step (3), cooling the hydroxyalkylcellulose obtained after completion of step (2) to 50 to 70 캜; And neutralizing the cooled hydroxyalkylcellulose.

The present invention also provides a hydroxyalkylcellulose produced by the above-described method.

According to the method for producing a hydroxyalkylcellulose of the present invention, the step of reacting hydroxyalkylcellulose with a crosslinking agent can delay the time for dissolving the hydroxyalkylcellulose in water.

Accordingly, the hydroxyalkylcellulose prepared according to the present invention can be subjected to a washing process for removing impurities by using water alone as in the case of hydroxyalkylalkylcellulose. That is, according to the present invention, it is possible to carry out a cleaning process for removing impurities in an economical and easy manner without complicated processes required for cleaning of existing hydroxyalkylcellulose or facilities such as centrifugal separators at various stages.

In addition, the hydroxyalkyl cellulose produced according to the above-described preparation method has improved chromaticity and is easily applicable to household articles.

1 is a flow chart showing a process for producing hydroxyalkylcellulose according to the present invention.

(1) reacting cellulose with an alkalizing agent to obtain an alkalized cellulose; (2) reacting the alkalized cellulose with an etherifying agent to obtain hydroxyalkylcellulose; (3) reacting the hydroxyalkylcellulose with a crosslinking agent; And (4) washing the hydroxyalkylcellulose reacted with the cross-linking agent with water to remove impurities. The present invention also relates to a hydroxyalkylcellulose produced by the method and a method for producing the hydroxyalkylcellulose.

Hereinafter, a method for producing hydroxyalkylcellulose according to the present invention will be described in detail with reference to FIG.

(1) Alkalized Cellulose Preparation Step

This step is a step of reacting cellulose with an alkalizing agent to obtain an alkalized cellulose. After adding cellulose and a reaction solvent to the reactor, an alkalizing agent is added to convert the cellulose to an alkalized cellulose. This step is intended to facilitate the reaction of the etherification agent and the cellulose described below by weakening the crystal structure of the cellulose. That is, the alkalizing agent plays a role of promoting the reaction of the cellulose with the etherifying agent. The alkali-converted cellulose thus converted must be agitated at room temperature (20 to 30 ° C) for a certain period of time, so that its crystal structure can be uniformly weakened.

This step can be carried out under the reaction conditions and reaction conditions commonly used in this field. For example, in the case of cellulose, pulp cellulose obtained from cotton or wood may be used. As the reaction solvent, any one or a mixture of two or more selected from water, tertiary butyl alcohol, isopropyl alcohol and acetone Solvents may be used, but are not limited thereto. At this time, the amount of the reaction solvent may be 600 to 1500 parts by weight based on 100 parts by weight of the cellulose.

As the alkalizing agent, an alkali metal hydroxide generally used in this field may be used. For example, as the alkalizing agent, any one or two or more selected from the group consisting of sodium hydroxide, potassium hydroxide, and lithium hydroxide may be used, but the present invention is not limited thereto. The amount of the alkalizing agent may be 5 to 600 parts by weight based on 100 parts by weight of the cellulose. If the amount of the alkalizing agent is within the above range, the etherifying agent is uniformly substituted in the whole of the cellulose in the step (2) to be described later, and the reactivity of the etherating agent is increased, so that the cellulose ether having the desired degree of substitution can be obtained.

(2) Step of producing hydroxyalkylcellulose

This step is a step of reacting the alkalized cellulose obtained in the step (1) with an etherifying agent to obtain hydroxyalkylcellulose. The etherifying agent is added to the alkalized cellulose, and the temperature is elevated to carry out the etherification reaction.

This step can likewise be carried out under the reaction conditions and reaction conditions commonly used in this field. For example, the reaction temperature starts at an initial temperature of 10 to 30 ° C., and may be increased to 90 to 120 ° C. after the addition of the etherifying agent, and may be performed for 10 to 150 minutes after the temperature rise. If the reaction temperature after the introduction of the etherifying agent is within the above range, the etherifying agent may have a sufficient heat of reaction for reacting with the cellulose, and the risk of an increase in manufacturing cost and an adverse reaction due to use of an excessive heat source may be reduced. In addition, when the reaction time is within the above range, the reactivity of the etherifying agent can be kept high and the productivity of hydroxyalkylcellulose can be improved. Although the reaction pressure at this stage varies depending on the temperature, it is preferable to adjust the maximum pressure in the range of 7 to 13 kgf / cm ² in consideration of reactivity and stability.

As the etherating agent, an alkylene oxide may be used, and preferably ethylene oxide may be used. The amount of the etherifying agent may be 60 to 150 parts by weight based on 100 parts by weight of the cellulose. If the amount of the etherifying agent is within the above range, the risk of an abnormal reaction and formation of by-products are reduced in the process, and cellulose ether having a desired degree of substitution can be obtained.

The method for producing hydroxyethylcellulose according to the present invention is characterized in that the hydroxyalkylcellulose obtained after the completion of the step (2) is added to the hydroxyalkylcellulose obtained in the step (2) of hydrolytic alkylcellulose and the step (3) Cooling to 70 < 0 > C, and neutralizing the cooled hydroxyalkylcellulose.

Specifically, the step of cooling the hydroxyalkylcellulose to 50-70 ° C may be carried out in a manner to prevent the neutralization reaction and the local neutralization reaction occurring during the introduction of the neutralizing agent in the next step of "neutralizing the hydroxyalkylcellulose" .

As the neutralizing agent used in the step of neutralizing the hydroxyalkylcellulose, any oxidizing agent generally used in the field can be used, and preferably one or more selected from the group consisting of nitric acid, acetic acid and hydrochloric acid, Which may be diluted with water to a concentration of 40 to 90%. The amount of the neutralizing agent may be equal to or greater than the amount of the alkaline agent initially introduced. When the neutralizing agent is put in the above range, the state of the slurry after the completion of the etherification reaction can be maintained at a slightly acidic or neutral state, thereby improving the process efficiency of subsequent crosslinking and washing and improving the physical properties of the final product . Since the neutralization reaction proceeds very rapidly, there is no particular time limitation. However, the neutralization reaction is performed for 10 minutes or more in general process operation, and it is preferable to proceed at 40 ° C or more. In addition, the neutralization reaction is atmospheric or slight pressure (1kgf / cm ² By weight).

(3) crosslinking step of hydroxyalkylcellulose

This step is a step for reacting the hydroxyalkylcellulose with a crosslinking agent to delay the time for dissolving the hydroxyalkylcellulose obtained in the step (2) in water. Specifically, at this stage, the hydroxyalkylcellulose forms crosslinks with other hydroxyalkylcelluloses through the crosslinking agent. The crosslinked hydroxyalkylcellulose may have a delay in dissolving in water, and consequently water A hydroxyalkyl cellulose which can be cleaned by using a solvent can be provided.

At this stage, the conditions of the crosslinking reaction such as pH, reaction temperature, reaction time and amount of crosslinking agent treatment are very important.

First, this step is preferably carried out in a pH range of 2-6. When the pH is less than 2, it is difficult to control the crosslinking reaction. Thus, it can be converted into a structure that is not soluble in water due to over reaction. On the other hand, when the pH is more than 6, There is a fear that the hydroxyalkylcellulose melts in water and can not be cleaned.

The pH can be controlled by the addition of an acid component commonly used in the art, and preferably can be controlled by one or more acids selected from the group consisting of nitric acid, acetic acid and hydrochloric acid. The acid may be appropriately selected from the above-mentioned "step of reacting hydroxyalkylcellulose with a crosslinking agent ", but preferably the acid is added to the hydroxyalkylcellulose obtained in the step (2) before the crosslinking agent is added Lt; / RTI >

It is also preferable that this step is carried out at a reaction temperature range of 65 to 85 캜 for 10 to 30 minutes. When the reaction temperature is less than 65 ° C or the reaction time is less than 10 minutes, the crosslinking reaction efficiency is lowered, and the hydroxyalkylcellulose is dissolved in water when washing with water after completion of the reaction. On the other hand, when the reaction temperature exceeds 85 ° C or when the reaction time exceeds 30 minutes, the efficiency of the crosslinking reaction is insufficient relative to the reaction temperature or time, which is uneconomical and may increase the chromaticity due to the excessive reaction.

The crosslinking agent used in the present invention may be selected from the group consisting of glutaraldehyde, glyoxal, malondialdehyde, succindialdehyde, terephthalaldehyde, formadehyde, acetaldehyde, ) Selected from the group consisting of propionaldehyde, butyraldehyde, benzaldehyde, cinnamaldehyde, 4-methylbenzaldehyde and furfural. May include more than one, and more preferably, may contain glyoxal.

The amount of the cross-linking agent to be treated is preferably 2 to 18 parts by weight based on 100 parts by weight of the hydroxyalkylcellulose obtained in the step (2). When the amount is less than 2 parts by weight, the efficiency of the crosslinking reaction is lowered. When the reaction is completed, the hydroxyalkylcellulose may be dissolved in the water during washing with water, and the washing may not be possible. On the other hand, if the amount is more than 18 parts by weight, It is liable to be affected by the physical properties of the final product.

(4) Cleaning step

In this step, the hydroxyalkyl cellulose reacted with the crosslinking agent in the step (3) is washed with water to remove impurities.

In the case of hydroxyalkylcellulose crosslinked through the step (3), impurities can be easily removed only by a simple rinsing with water. Therefore, it is possible to remove impurities without a water / organic solvent mixture solvent and multi-stage centrifugal separator, which are required for conventional hydroxyalkylcellulose washing.

Since the hydroxyalkyl cellulose in which the impurities are removed as described above is improved in chromaticity, the hydroxyalkyl cellulose according to the present invention can produce hydroxyalkylcellulose having excellent quality with a low yellow index value without any additional process for improving chromaticity, Can be prepared.

The hydroxyalkylcellulose obtained through the above steps may be subjected to a post-treatment, such as filtration, drying, pulverization and classification, which may be carried out by a general method in this field.

Meanwhile, the present invention provides hydroxyalkylcellulose prepared according to the above-mentioned preparation method. Since the hydroxyalkyl cellulose exhibits excellent quality close to white due to its improved chromaticity, it can be used industrially in a wide range of fields such as medicines, foods, cosmetics, and building materials as well as applications that emphasize chromaticity such as household goods . Here, chromaticity generally means yellow when the powder of cellulose ether is measured. The chromaticity scale is a yellow index (YI), which is often measured with a spectrophotometer. The lower the value of the yellow index, the closer it is to white, and the better the quality, the better.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these embodiments.

Example One

200 g of cellulose was put in a pressure reactor and 1800 ml of a mixed solvent of tertiary butyl alcohol / isopropyl alcohol / water as a reaction solvent (weight ratio = 83: 6: 11) was added and 126 g of 50% sodium hydroxide solution as an alkalizing agent was added. Lt; 0 > C and 200 rpm with stirring to obtain an alkalized cellulose.

Then, 212 g of ethylene oxide, which is an etherifying agent, was added to the alkalized cellulose at 25 ° C., and then the reaction temperature was raised to 100 ° C. and etherification reaction was carried out at a pressure of ⁸ kgf / cm ² . After the temperature was elevated, the etherification reaction was carried out at the same temperature for 60 minutes. When the reaction was completed, the reaction mixture was cooled to 60 ° C and neutralized by adding 165 g of 60% nitric acid (HNO ₃ ) as a neutralizing agent to obtain a hydroxyethylcellulose slurry. At this time, 316.96 g of hydroxyethylcellulose produced in the hydroxyethylcellulose slurry was obtained.

After the neutralization was completed, hydrochloric acid (HCl) was added to the slurry to adjust the pH to 3, 6.4 g of glyoxal (about 2 parts by weight based on 100 parts by weight of hydroxyethylcellulose) as a crosslinking agent was added, Lt; 0 > C, followed by a crosslinking reaction at the same temperature for 10 minutes.

After completion of the crosslinking reaction, the reaction solvent was removed from the slurry, washed with 2500 ml of water twice, filtered, and dried to obtain hydroxyethylcellulose.

Examples 2 to 3 and Comparative Example 1

Hydroxyethyl cellulose was obtained in the same manner as in Example 1, except that pH, crosslinking agent throughput, and time and temperature were controlled as shown in Table 1 below.

Comparative Example 2

Then, 212 g of ethylene oxide, which is an etherifying agent, was added to the alkalized cellulose at 25 ° C., and then the reaction temperature was raised to 100 ° C. and etherification reaction was carried out at a pressure of ⁸ kgf / cm ² . After the temperature was elevated, the etherification reaction was carried out at the same temperature for 60 minutes. When the reaction was completed, the reaction mixture was cooled to 60 ° C and neutralized by adding 165 g of 60% nitric acid (HNO ₃ ) as a neutralizing agent to obtain a hydroxyethylcellulose slurry.

After neutralization was completed, the reaction solvent was removed from the slurry, and then 4000 ml of an acetone / water mixed solvent of 80% concentration, 3700 ml of an acetone / water mixed solvent of 85% concentration, 3520 ml of an acetone / water mixed solvent of 90% Of acetone / water mixed solvent (3300 ml), filtered, and dried to obtain hydroxyethylcellulose.

1. Chromaticity

The yellow index (YI) of hydroxyethylcellulose prepared according to Examples 1 to 3 and Comparative Examples 1 and 2 was measured with a color difference meter (DATACOLOR, 650 ^TM ), and the measured values are shown in the following Table 1 as chromaticity . At this time, the lower the yellow index value is, the closer to white color, the better the quality is evaluated.

2. Viscosity

Hydroxyethylcellulose prepared according to Examples 1 to 3 and Comparative Examples 1 and 2 was dissolved in water to prepare a hydroxyethylcellulose solution having a concentration of 1% by weight. Then, the viscosity of the cellulose ether solution was measured by Brookfield The results are shown in Table 1 below. The results are shown in Table 1. < tb > < TABLE >

pH condition Cross-linker throughput
(Parts by weight) Temperature
(° C) time
(minute) Chromaticity Viscosity
(cps) Example 1 3 2 75 20 7.6 2450 Example 2 5 7 65 10 6.9 2360 Example 3 6 15 72 30 7.3 2490 Comparative Example 1 2 20 85 30 5.9 320 Comparative Example 2 × × × × 13 2320

As shown in Table 1, the hydroxyethyl cellulose having undergone the crosslinking reaction under the conditions of Examples 1 to 3 of the present invention exhibited excellent chromaticity as compared with the hydroxyethyl cellulose of Comparative Example 2 in which the crosslinking reaction was not carried out . Unlike the hydroxyethylcellulose of Comparative Example 2, which must be cleaned using a mixed solvent of water and an organic solvent, the hydroxyethylcellulose of Examples 1 to 3 can be cleaned using water alone.

On the other hand, in Comparative Example 1 in which the crosslinking agent throughput was 20 parts by weight, the chromaticity was excellent, but the viscosity was reduced and the application was limited, so that the preferred treatment amount of the crosslinking agent was 2 to 18 parts by weight based on 100 parts by weight of cellulose .

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiment, but is to be accorded the widest scope consistent with the appended claims and their equivalents. Should be construed as being included in the scope of the present invention.

Claims

(1) reacting cellulose with an alkalizing agent to obtain an alkalized cellulose;
(2) reacting the alkalized cellulose with an etherifying agent to obtain hydroxyalkylcellulose;
(3) reacting the hydroxyalkylcellulose with a crosslinking agent; And
(4) washing the hydroxyalkylcellulose reacted with the cross-linking agent with water to remove impurities.

The method according to claim 1,
Wherein the step (3) is carried out in a pH range of 2 to 6.

3. The method of claim 2,
Wherein the pH is controlled by one or more acids selected from the group consisting of nitric acid, acetic acid and hydrochloric acid.

The method according to claim 1,
Wherein the step (3) is carried out at a reaction temperature range of 65 to 85 ° C for 10 to 30 minutes.

The method according to claim 1,
The crosslinking agent may be selected from the group consisting of glutaraldehyde, glyoxal, malondialdehyde, succindialdehyde, terephthalaldehyde, formadehyde, acetaldehyde, propionaldehyde, and one or more selected from the group consisting of propionaldehyde, butyraldehyde, benzaldehyde, cinnamaldehyde, 4-methylbenzaldehyde and furfural. Wherein the hydroxyalkyl cellulose is a hydroxyalkyl cellulose.

The method according to claim 1,
Wherein the treatment amount of the cross-linking agent in the step (3) is 2 to 18 parts by weight based on 100 parts by weight of the hydroxyalkyl cellulose obtained from the step (2).

The method according to claim 1,
Between the step (2) and the step (3)
Cooling the hydroxyalkylcellulose obtained after completion of the step (2) to 50 to 70 캜; And
And neutralizing the cooled hydroxyalkylcellulose. &Lt; Desc / Clms Page number 20 >

A hydroxyalkylcellulose prepared according to any one of claims 1 to 7.