CN104774273A - Method for preparing phosphate ester starch slurry - Google Patents

Abstract

The invention discloses a method for preparing phosphate starch slurry, which comprises adding water and raw starch into a reactor, preparing starch milk with a mass percent concentration of raw starch of 10%-15%, and adding starch milk to the starch under stirring conditions. Add 5%-15% phosphating agent relative to the original starch mass and 2%-5% composite catalyst equivalent to the starch weight to the milk, adjust the pH value between 6.0-8.5, turn on the heating, and control the temperature ratio of the reactor Correspondingly, the complete gelatinization temperature of raw starch is 0-50°C higher. After the reaction, the obtained slurry is phosphate starch slurry, which can be directly used for warp yarn sizing, eliminating the need for phosphate starch to be processed in the starch factory. The special production process greatly saves the production cost, simplifies the production process, and reduces the environmental pollution caused by the waste water discharged in the production process of phosphate starch.

Description

A kind of method for preparing phosphate starch size

technical field

The invention relates to a method for preparing starch ester derivatives, in particular to a method for preparing phosphate ester starch slurry.

Background technique

At present, phosphate starch sizing in the textile industry usually directly purchases phosphate starch produced by a starch factory, adds water to prepare starch milk of a certain concentration, and after heating and gelatinizing, phosphate starch sizing that can be used in the sizing process is obtained. And starch factory can adopt dry method or wet method when producing phosphate starch, conventional wet method is: add 15% phosphate mixture of starch quality and starch quality to 35%-42% starch milk 2% urea is used as a catalyst, and the reactants are mixed uniformly, and reacted for 3-10 hours at a temperature of 30-60°C and a pH value of 5.0-6.5, and the reaction product is separated from solid and liquid, and 2 The double amount of 2.5% sodium chloride aqueous solution is fully stirred and dispersed into a milky state, then left to soak for 30 minutes, solid-liquid separation again, the solid is repeated for at least 6 times, and finally rinsed with distilled water for 3 times, and the finally obtained solid is dried and obtained Phosphate starch. In this production process, the production steps are cumbersome, the production cost is high, and the energy consumption is large. Especially in the post-treatment process of phosphate ester starch, more acid-containing wastewater will be discharged, which will pollute the environment. Moreover, phosphate starch is prepared at a gelatinization temperature lower than that of the original starch, and the starch is in a granular state during preparation, which will hinder the diffusion of the esterification agent into the interior of the starch granules, affecting the reaction efficiency of the esterification agent and the degree of substitution of the phosphate starch. .

Contents of the invention

In view of the above-mentioned problems in the prior art, the technical problem to be solved by the present invention is to provide a method for preparing starch phosphate slurry.

In order to solve the problems of the technologies described above, the technical solution adopted in the present invention is: a method for preparing starch phosphate slurry, comprising the following steps:

(a) add water and original starch (its chemical structure and property are identical with existing in raw material) in reactor, prepare the starch milk that the mass percent concentration of original starch is 10%-15%, described original starch is At least one of corn starch, potato starch, and tapioca starch;

(b) under stirring condition, add relative to the original starch quality 5%-15% phosphatizing reagent and the composite catalyst equivalent to starch weight 2%-5% in starch milk, described phosphatizing reagent is At least one of sodium tripolyphosphate, sodium trimetaphosphate or sodium pyrophosphate, the composite catalyst is urea and sodium hypophosphite, wherein the quality of urea is 0.5-2 times that of sodium hypophosphite;

(c) Add acid to adjust the pH value between 6.0-8.5, turn on the heating, control the temperature of the reactor to be 0-50°C higher than the complete gelatinization temperature of the corresponding raw starch, and maintain the temperature until the end of the reaction.

In order to further improve the reaction efficiency and the degree of substitution of phosphate starch, the further technical solution adopted by the present invention is: a method for preparing phosphate starch slurry, comprising the following steps:

(a) add water and original starch (its chemical structure and property are identical with when existing in raw material) in reactor, prepare the starch milk that the mass percent concentration of original starch is 12%-14%, described original starch is At least one of corn starch, potato starch, and tapioca starch;

(b) under agitation, add 7%-10% phosphating agent relative to the original starch quality and a composite catalyst equivalent to 3%-4% starch weight in the starch milk, and the phosphating agent is At least one of sodium tripolyphosphate, sodium trimetaphosphate or sodium pyrophosphate, the composite catalyst is urea and sodium hypophosphite, wherein the quality of urea is 1-1.5 times that of sodium hypophosphite;

(c) Add dilute hydrochloric acid or dilute sulfuric acid to adjust the pH value between 6.5-7.5, turn on the heating, control the temperature of the reactor to be 10-30°C higher than the complete gelatinization temperature of the corresponding raw starch, and maintain the temperature until the end of the reaction.

Compared with the prior art, the inventive method has the following beneficial effects:

(1) The present invention organically combines the preparation of starch size and the production of phosphate starch size, and realizes the one-pot method of the production of starch preparation and phosphate starch size and phosphate starch On-line production of materials, the obtained phosphate starch size can be directly used for warp yarn sizing, which avoids the special production process of phosphate starch in the starch factory or size factory, greatly saves production costs, simplifies the production process, and reduces The environmental pollution caused by the waste water discharged in the production process of phosphate ester starch was eliminated.

(2) Since the starch slurry is in a gelatinized state when the phosphating reaction occurs, the molecular chain is fully extended and can be fully contacted with the phosphating reagent, which improves the uniformity of the reaction and significantly improves the phosphating reagent. Reaction efficiency and degree of substitution of phosphate starch.

Detailed ways

The present invention will be further described in detail through specific examples below. The following descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention.

Example 1

Take by weighing 100kg tapioca starch (the gelatinization complete temperature is 70 ℃), add 900kg water to make the starch milk that the mass percent concentration is 10%, start the mixer and stir evenly. Add 5kg of sodium pyrophosphate, 0.67kg of urea, and 1.33kg of sodium hypophosphite, stir evenly, and then use 5% dilute hydrochloric acid solution to adjust the pH of the system to 7.5-8.5. Turn on the heating while stirring. When the temperature of the system reaches 70°C, control the heating and keep it at 70°C, and react at this temperature for 120 minutes. Turn off the heating, and the obtained slurry is the phosphate starch slurry prepared on-line.

Take an appropriate amount of the phosphate starch slurry prepared above, and fully wash the starch slurry with 65%-70% alcohol, wash away the unreacted pyrophosphate in the slurry, and precipitate the phosphate starch. Use ammonium molybdate solution to check whether the unreacted pyrophosphate is completely washed out. The precipitated starch phosphate was vacuum dried at low temperature to constant weight. Weighing an appropriate amount of phosphate starch sample that has been dried to constant weight, the measured degree of substitution of the sample is 0.009, and the calculated reaction efficiency of sodium pyrophosphate is 50%.

Take an appropriate amount of the phosphate starch slurry prepared above, adjust its mass concentration to 6.0%, measure its viscosity with NDJ-79 rotary viscometer as 15.6mPa.s, and its thermal viscosity stability is 88.5%.

Take an appropriate amount of the phosphate starch slurry prepared above, adjust its mass concentration to 6.0%, and prepare a size film under constant temperature and humidity conditions. The measured breaking strength of the size film is 22.5N/mm ² , and the elongation at break is 3.8%. , The moisture absorption rate of the serous film is 25.6%.

Take an appropriate amount of the phosphate starch slurry prepared above, adjust its mass concentration to 1.0%, and measure its adhesion to 14.5tex pure cotton roving as 65.9N, and its adhesion to 13tex63/35 polyester-cotton roving as 115.8N.

Example 2

Weigh 150kg of cornstarch (the gelatinization complete temperature is 72°C), add 850kg of water to make starch milk with a mass percentage concentration of 15%, and start the mixer to stir evenly. Add 22.5kg of sodium trimetaphosphate, 3.33kg of urea, and 1.67kg of sodium hypophosphite, stir evenly, and then use 5% dilute hydrochloric acid solution to adjust the pH of the system to 6.0-7.0. Turn on the heating while stirring. When the temperature of the system reaches 122°C, control the heating and keep it at 122°C, and react at this temperature for 30 minutes. Turn off the heating, and the obtained slurry is the phosphate starch slurry prepared on-line.

According to the method of Example 1, the measured substitution degree of the sample is 0.022, and the calculated reaction efficiency of sodium trimetaphosphate is 28%; the viscosity is 16.7 mPa.s, and the thermal viscosity stability is 91.0%. The breaking strength of the size film is 23.2N/mm ² , the elongation at break is 3.2%, and the moisture absorption rate of the size film is 25.4%. The force is 121.3N.

Example 3

Weigh 120kg of potato starch (the complete gelatinization temperature is 67°C), add 880kg of water to make starch milk with a mass percentage concentration of 12%, and start the mixer to stir evenly. Add 8.4 kg of sodium tripolyphosphate, 1.5 kg of urea, and 1.5 kg of sodium hypophosphite, stir evenly, and then use 5% dilute sulfuric acid solution to adjust the pH of the system to 6.5-7.5. Heating was started while stirring, and when the temperature of the system reached 77°C, the heating was controlled and kept at 77°C, and the reaction was carried out at this temperature for 90 minutes. Turn off the heating, and the obtained slurry is the phosphate starch slurry prepared on-line.

According to the method of Example 1, the measured substitution degree of the sample was 0.017, and the calculated reaction efficiency of sodium tripolyphosphate was 55%; the viscosity was 17.3 mPa.s, and the thermal viscosity stability was 87.3%. The breaking strength of the size film was 19.5 N/mm ² , the breaking elongation was 4.2%, and the moisture absorption rate of the size film was 23.7%. The adhesion to 14.5tex pure cotton roving is 68.3N, and the adhesion to 13tex63/35 polyester-cotton roving is 110.7N.

Example 4

Weigh 140kg of potato starch (the complete gelatinization temperature is 67°C), add 860kg of water to make starch milk with a mass percentage concentration of 14%, and start the mixer to stir evenly. Add 14kg of sodium tripolyphosphate, 3.36kg of urea, and 2.24kg of sodium hypophosphite, stir evenly, and then use 5% dilute sulfuric acid solution to adjust the pH of the system to 6.5-7.5. Turn on the heating while stirring. When the temperature of the system reaches 97°C, control the heating and keep it at 97°C, and react at this temperature for 90 minutes. Turn off the heating, and the obtained slurry is the phosphate starch slurry prepared on-line.

According to the method of Example 1, the measured substitution degree of the sample is 0.025, and the calculated reaction efficiency of sodium tripolyphosphate is 57%; the viscosity is 17.8 mPa.s, and the thermal viscosity stability is 84.7%. The breaking strength of the size film was 19.8 N/mm ² , the breaking elongation was 4.0%, and the moisture absorption rate of the size film was 23.8%. The adhesion to 14.5tex pure cotton roving is 65.3N, and the adhesion to 13tex63/35 polyester-cotton roving is 107.6N.

Claims (2)

1. A method for preparing starch phosphate size, comprising the following steps: (a) add water and native starch (its chemical structure and property are identical with existing in raw material) in container, prepare the starch milk that the mass percent concentration of raw starch is 10%-15%, and described raw starch is corn At least one of starch, potato starch, and tapioca starch. (b) under agitation, add 5%-15% phosphating agent relative to the original starch weight and a composite catalyst equivalent to 2%-5% of the original starch weight in the starch milk, and the phosphating agent It is at least one of sodium tripolyphosphate, sodium trimetaphosphate or sodium pyrophosphate, and the composite catalyst is urea and sodium hypophosphite, wherein the quality of urea is 0.5-2 times that of sodium hypophosphite; (c) adding acid to adjust the pH value between 6.0-8.5, heating, controlling the reaction temperature to be 0-50°C higher than the complete gelatinization temperature of the corresponding original starch, and maintaining this temperature until the end of the reaction. 2. the method for preparing starch phosphate size according to claim 1, comprises the following steps: (a) add water and original starch (its chemical structure and property are identical with when existing in raw material) in container, prepare the starch milk that the mass percent concentration of original starch is 12%-14%, and described original starch is corn At least one of starch, potato starch, and tapioca starch. (b) under agitation, add 7%-10% phosphating agent relative to the original starch quality and a composite catalyst equivalent to 3%-4% of the original starch weight in the starch milk, the phosphating agent It is at least one of sodium tripolyphosphate, sodium trimetaphosphate or sodium pyrophosphate, and the composite catalyst is urea and sodium hypophosphite, wherein the quality of urea is 1-1.5 times that of sodium hypophosphite; (c) adding dilute hydrochloric acid or dilute sulfuric acid to adjust the pH value between 6.5-7.5, heating, controlling the reaction temperature to be 10-30°C higher than the complete gelatinization temperature of the corresponding raw starch, and maintaining this temperature until the end of the reaction.