阅读说明：本技术 一种速溶性羧甲基淀粉或羧甲基纤维素浆料的制备方法 (Preparation method of instant carboxymethyl starch or carboxymethyl cellulose pulp ) 是由 范雪荣 吴燕 高卫东 徐进 荣瑞萍 汤健 于 2019-11-02 设计创作，主要内容包括：一种速溶性羧甲基淀粉或羧甲基纤维素浆料的制备方法,利用羧甲基淀粉或羧甲基纤维素中含有大量反应性活泼的羟基,与加入的乙二醛发生亲核加成反应生成不稳定的半缩醛,直接制备速溶性非常好的速溶型羧甲基淀粉或羧甲基纤维素,解决羧甲基淀粉和羧甲基纤维素在纺织上浆投料溶解过程中易结块、结团,溶解速度慢、溶解不完全的问题。本发明在制备过程中所加入的乙醇通过蒸馏充分回收利用、成本低、不污染环境,所制备的半缩醛型羧甲基淀粉或羧甲基纤维素中的半缩醛不稳定,在溶解时会发生逆反应,重点生成羧甲基淀粉或羧甲基纤维素,产品的性能不受影响,具有溶解速度快、溶解效率高等诸多优点,溶解速率是常规羧甲基淀粉和羧甲基纤维素的数十倍。(A method for preparing instant carboxymethyl starch or carboxymethyl cellulose pulp, which utilizes the nucleophilic addition reaction of a large amount of reactive and active hydroxyl contained in carboxymethyl starch or carboxymethyl cellulose and added glyoxal to generate unstable hemiacetal, directly prepares instant carboxymethyl starch or carboxymethyl cellulose with good instant solubility, and solves the problems of easy caking and agglomeration, low dissolution speed and incomplete dissolution of carboxymethyl starch and carboxymethyl cellulose in the process of feeding and dissolving sizing for textile. The ethanol added in the preparation process is fully recycled by distillation, the cost is low, the environment is not polluted, the hemiacetal in the prepared hemiacetal carboxymethyl starch or carboxymethyl cellulose is unstable, reverse reaction can occur during dissolution, the carboxymethyl starch or carboxymethyl cellulose is mainly generated, the performance of the product is not affected, and the preparation method has the advantages of high dissolution speed, high dissolution efficiency and the like, wherein the dissolution speed is tens of times of that of the conventional carboxymethyl starch and carboxymethyl cellulose.)

1. A preparation method of instant carboxymethyl starch or carboxymethyl cellulose pulp is characterized in that:

preparing carboxymethyl starch or carboxymethyl cellulose according to a conventional method, washing the carboxymethyl starch or carboxymethyl cellulose to be neutral by adopting an alcohol/water solution, adding ethanol with the mass of 100-150% of that of the carboxymethyl starch or carboxymethyl cellulose and the concentration of more than 85%, stirring and uniformly mixing, then adding glyoxal with the mass of 5-20% of that of the carboxymethyl starch or carboxymethyl cellulose and 0.3-1.2% of a potential acid catalyst, heating to 35-55 ℃, slowly stirring for reaction for 30-90min, and distilling and recovering ethanol to obtain the instant carboxymethyl starch or carboxymethyl cellulose.

2. The method for producing a instant carboxymethyl starch or carboxymethyl cellulose pulp according to claim 1, characterized in that: the degree of substitution of the carboxymethyl starch is 0.10-0.90, and the degree of substitution of the carboxymethyl cellulose is 0.50-1.20.

3. The method for producing a instant carboxymethyl starch or carboxymethyl cellulose pulp according to claim 1, characterized in that: the addition amount of the glyoxal is 8-18% of the mass of the carboxymethyl starch or the carboxymethyl cellulose.

4. The method for producing a instant carboxymethyl starch or carboxymethyl cellulose pulp according to claim 1, characterized in that: the potential acid catalyst is magnesium chloride or aluminum trichloride.

5. The method for producing a instant carboxymethyl starch or carboxymethyl cellulose pulp according to claim 1 or 4, characterized in that: the adding amount of the potential acid catalyst is 0.5-1.0% of the mass of the carboxymethyl starch or the carboxymethyl cellulose.

6. The method for producing a instant carboxymethyl starch or carboxymethyl cellulose pulp according to claim 1, characterized in that: the reaction temperature for preparing the instant carboxymethyl starch or carboxymethyl cellulose pulp is 40-50 ℃, and the reaction time is 45-75 min.

Technical Field

The invention belongs to the technical field of textile warp sizing, and particularly relates to a method for preparing a quick-soluble carboxymethyl starch or carboxymethyl cellulose slurry by utilizing a nucleophilic addition reaction of glyoxal and hydroxyl on carboxymethyl starch or carboxymethyl cellulose in an ethanol solution to generate unstable hemiacetal.

Background

Warp sizing is a key process in textile production, and the sizing quality directly affects the weaving efficiency. The sizing quality of the warp yarn mainly depends on the composition and proportion of the sizing agent, particularly the adhesive property of the sizing agent. Carboxymethyl starch and carboxymethyl cellulose have good water solubility, good adhesion performance to cellulose fibers such as cotton, viscose and the like, and other excellent sizing performances, and are very important textile sizing agents.

However, carboxymethyl starch and carboxymethyl cellulose are very water-soluble and have a large surface activity, and are agglomerated when they are in contact with water, and when they are dissolved in cold or hot water, carboxymethyl starch and carboxymethyl cellulose on the surface are dissolved and agglomerated, and thus, the undissolved carboxymethyl starch and carboxymethyl cellulose are coated inside the agglomerate, and it is difficult to dissolve the carboxymethyl starch and carboxymethyl cellulose once they are agglomerated. In order to solve the problem of dissolution of carboxymethyl starch and carboxymethyl cellulose in production, when the carboxymethyl starch and carboxymethyl cellulose are prepared and used, water is required to be added in advance for soaking and placing for one day, the carboxymethyl starch and carboxymethyl cellulose are dissolved in water after being transparent, but the carboxymethyl starch and carboxymethyl cellulose cannot be dissolved uniformly, the preparation time is long, the dissolution is incomplete, the product quality is influenced, and the production requirements cannot be met.

Other methods for improving the instant solubility of carboxymethyl starch and carboxymethyl cellulose have also been studied in production, such as soaking in ethanol solution with concentration of over 60% for a period of time, and then adding water to dissolve the solution to the desired concentration with stirring. However, this method requires a higher concentration of ethanol solution, and the low concentration of ethanol does not solve the instant dissolution problem, and it requires ethanol having a concentration 7-8 times the amount of carboxymethyl starch and carboxymethyl cellulose, which is not economical in production and increases the cost. On the other hand, the method does not solve the problem of immediate use in production.

In the production, a glycerol solution with the concentration of 99% is also added to soak and disperse the carboxymethyl starch and the carboxymethyl cellulose, and the dosage of the glycerol soaking solution is generally 6-8 times of the dosage of the carboxymethyl starch and the carboxymethyl cellulose. Or firstly soaking and dispersing by using 80% -95% of glycerol solution, and then adding 25% -75% of glycerol solution into the soaking solution for dissolving. The method also has the problems of high cost and incapability of being instantly dissolved for use because the method needs to soak and disperse for a certain time and then dissolve, and the added glycerol influences the use performance of the final product.

Disclosure of Invention

The purpose of the invention is as follows: in the preparation process of carboxymethyl starch or carboxymethyl cellulose, the invention utilizes the fact that a large amount of reactive and active hydroxyl groups contained in carboxymethyl starch or carboxymethyl cellulose and added glyoxal undergo nucleophilic addition reaction to generate unstable hemiacetal, and directly prepares instant carboxymethyl starch or carboxymethyl cellulose with very good instant solubility, thereby solving the problems of easy caking and agglomeration, low dissolution speed and incomplete dissolution of carboxymethyl starch or carboxymethyl cellulose in the dissolution process.

The technical scheme is as follows: in order to solve the technical problems, the invention provides a preparation method of instant carboxymethyl starch or carboxymethyl cellulose pulp,

preparing carboxymethyl starch or carboxymethyl cellulose according to a conventional method, washing the carboxymethyl starch or carboxymethyl cellulose to be neutral by adopting an alcohol/water solution, adding ethanol with the mass of 100-150% of that of the carboxymethyl starch or carboxymethyl cellulose and the concentration of more than 85%, stirring and uniformly mixing, then adding glyoxal with the mass of 5-20% of that of the carboxymethyl starch or carboxymethyl cellulose and 0.3-1.2% of a potential acid catalyst, heating to 35-55 ℃, slowly stirring for reaction for 30-90min, and distilling and recovering ethanol to obtain the instant carboxymethyl starch or carboxymethyl cellulose.

The degree of substitution of the carboxymethyl starch is 0.10-0.90, and the degree of substitution of the carboxymethyl cellulose is 0.50-1.20.

The addition amount of the glyoxal is 8-18% of the mass of the carboxymethyl starch or the carboxymethyl cellulose.

The potential acid catalyst is magnesium chloride or aluminum trichloride.

The adding amount of the potential acid catalyst is 0.5-1.0% of the mass of the carboxymethyl starch or the carboxymethyl cellulose.

The reaction temperature for preparing the instant carboxymethyl starch or carboxymethyl cellulose pulp is 40-50 ℃, and the reaction time is 45-75 min.

Carboxymethyl starch or carboxymethyl cellulose is prepared by a semi-dry method. 100g of corn starch or wood pulp cellulose is weighed and put into a kneader, and 30g of absolute ethyl alcohol is added. Introducing nitrogen, spraying 25g of 40% sodium hydroxide solution at room temperature, and alkalifying at 30 deg.C for 60 min. Then, 16g of 75% sodium monochloroacetate solution was sprayed in, and the reaction was carried out for about 3 hours while the temperature was raised to 40 ℃. After the reaction is finished, dilute hydrochloric acid solution is used for adjusting the pH value of the system to be 6.5-7.2. The temperature was then raised to 50 ℃ during which time oxygen was introduced at a rate controlled to reduce the moisture content of the reactants to 9% -12%. Cooling to room temperature to obtain carboxymethyl starch or carboxymethyl cellulose with substitution degree of about 0.5.

For the preparation of carboxymethyl starch or carboxymethyl cellulose of other degrees of substitution, reference is made to the above-mentioned methods.

Has the advantages that: compared with the prior art, the invention has the following remarkable advantages:

in the preparation process of carboxymethyl starch or carboxymethyl cellulose, the instant carboxymethyl starch or carboxymethyl cellulose is directly prepared by utilizing the fact that a large amount of reactive and active hydroxyl groups are contained in the carboxymethyl starch or carboxymethyl cellulose and nucleophilic addition reaction is carried out on the carboxymethyl starch or carboxymethyl cellulose and added glyoxal in an ethanol medium to generate unstable hemiacetal, and the problems of easy caking and agglomeration, low dissolution speed and incomplete dissolution of the carboxymethyl starch or carboxymethyl cellulose in the dissolution process are solved; the ethanol added in the process of preparing the instant carboxymethyl starch or carboxymethyl cellulose can be fully recycled by distillation after the preparation is finished, so that adverse effects on the environment are avoided, and the cost is not remarkably increased; the reaction of carboxymethyl starch or carboxymethyl cellulose and glyoxal to generate hemiacetal is a reversible reaction, the hemiacetal is unstable, the hemiacetal can be hydrolyzed to generate the original carboxymethyl starch or carboxymethyl cellulose and glyoxal again in the dissolving time, and the performance of the product is not affected; the instant carboxymethyl starch or carboxymethyl cellulose prepared by the method can be directly dissolved without soaking, so that the production process is simplified, the dissolving time is shortened, and the production efficiency is improved.

Detailed Description

The present invention will be further described with reference to the following examples.