CN101555287B - Cationic starch producing method - Google Patents

Abstract

The invention belongs to the field of paper making technology and in particular relates to a Cationic starch producing method. The specific steps of the process of the method include etherifying agentactivation and emulsification, etherification reaction, neutralization washing, dehydration, drying and finished product obtaining. Cationic starch materials produced according to the method is safe and also simply, conveniently and practically used, and has high reaction efficiency; the starch grains are not subject to pasting; the yield rate can be as high as 99 percent, and the reaction efficiency reaches 68 percent; and the property of the finished product is stable.

Description

A kind of cationic starch producing method

Technical field

The invention belongs to pulp technology for making paper, relate in particular to a kind of cationic starch producing method.

Background technology

Cationic starch is a kind of important derivatives of starch ethers.Because it has positive charge, can combine closely with electronegative fiber fines, filler, thereby be widely used in paper making wet part, as enhancing, retention, flocculating aids, can significantly improve paper quality, reduce consumption, reduce cost.The cationic starch huge market demand, various in style, structure by its aminocompound can be divided into: cationic starch such as tertiary amine-type, quaternary ammonium type, primary amine type, secondary amine type and miscellany (as imines etc.), wherein quaternary ammonium cation starch all can use and stable existence under the pH scope widely in neutrality, alkalescence etc., therefore has bigger commodity value.Cationic starch with high substitution degree can neutralize at wet end of machine and remove the interference of anionic species to papermaking.Usually the cationic starch of preparation DS＜0.1 can satisfy the paper making wet part requirement.Usually the reagent of the starch cationization of usefulness reaction is quaternary ammonium type 3-chloro-2-hydroxypropyl-trimethyl ammonium chloride etherifying reagent.This etherifying reagent all shows cation state under acid, neutrality, alkaline condition.

From production technique production cationic starch, can roughly be divided into four classes: (1) semidrying; (2) with water be the wet method of medium, this method is an industry production method commonly used; (3) dry method; (4) organic solvent method.These four kinds of technologies respectively have relative merits.Semidrying reaction efficiency height reaches more than 92%, can prepare substitution value greater than 0.05 cationic starch, and insufficient is that product impurity is many, reacts inhomogeneous, only occurs in starch particle surface mostly, influences result of use.Dry method can prepare DS＞0.1, more is at 0.1-1.0, but has the problem that reagent is residual and foreign matter content is many equally, and apparatus and process is required than higher.Organic solvent method is subjected to the restriction of cost and environment protection, produces cationic starch without this method usually.The wet method that with water is medium is China's the most frequently used cationic starch production technique at present.Wet processing has reaction evenly, the characteristics of good product quality, but can only prepare low degree of substitution, the cationic starch of common DS＜0.1, reaction efficiency (RE) is also lower, general RE is 60%-63%, the etherifying agent activation back shelf-time is short, complicated operation, and at high pH and slightly under the high-temperature, gelatinization easily takes place in starch especially tapioca (flour), and loss is big.

Wet method synthesis method of the prior art may further comprise the steps: the certain density starch suspension of preparation under alkaline condition adds the etherifying agent reaction.Its reaction formula is as follows:

Starch-OH+OH ^-→Starch-O ^-

Summary of the invention

The purpose of this invention is to provide a kind of preparation of cationic starch method, present method materials handling safety, operation of equipment is easy, the reaction efficiency height, the etherifying agent reaction efficiency can reach about 68%, the product yield height, and the dry yield can reach 99%, the cationic starch quality better of preparing uses extensively in papermaking.

A kind of cationic starch producing method, its concrete steps are:

(1) etherifying agent activation and accent breast: at normal temperatures, adding starch quality is that 2.3～11.5% content is 69% cationic etherifying agent 3-chloro-2-hydroxypropyl-trimethyl ammonium chloride, transfer PH to 11～12 with circulating line with 3000-4000L/h hydro-oxidation sodium solution, add 5-10% starch, be 3.45～7.47% Sodium sulfate anhydrous.min(99) to add starch weight in 10kg/ minute then, add remaining starch again, control starch adding speed is 100kg/ minute, PH is controlled at 11.5～11.6, concentration control 23～25 Baumes.

(2) etherification reaction: heat up, react 8～12h down at 40～55 ℃;

(3) neutralization: with in 8～10% hydrochloric acid and to prepare PH be 6～8 neutral cation starch;

(4) washing, dehydration, drying obtain finished product.

Starch is tapioca (flour) or W-Gum.

By above-mentioned technology, with being 2～4 acidic cation starch with preparing PH in 8～10% hydrochloric acid.

With any in tapioca (flour), the W-Gum be raw material, with 3-chloro-2-hydroxypropyl-trimethyl ammonium chloride (CHPTMA) is etherifying agent, under sodium hydroxide catalysis, adopts activation and two step of etherificate wet method synthetic method separately, the cationic starch that synthesizes low degree of substitution, its general formula is:

Starch-OH is a starch:

The cationic starch substitution value is 0.01～0.045.This product is used for the toughener and the ASA emulsifying agent of high-grade culture usefulness and high-grade package paper.

Beneficial effect of the present invention: the cationic starch material safety that the method for the invention makes, practicality easy and simple to handle, the reaction efficiency height, starch granules does not have gelatinization, and the yield height can reach 99%, and reaction efficiency reaches 68%, and end properties is stable.On the basis of wet process technique, etherifying agent activation and accent breast are carried out in an accent breast jar simultaneously, reduced operation link, under the room temperature, with circulation line add the alkali pattern, effectively to prevent the gelatinization of starch, help further etherification reaction and yield and improve.Provide the basis for reducing production costs, effectively reduce energy consumption, production cost, the cationic starch products quality better that makes, widespread use in papermaking is specially adapted to enhancement and the ASA emulsification of high-grade culture with paper and high-grade package paper.

Embodiment

Further specify technical scheme of the present invention below by embodiment, but do not exceed with embodiment.

Embodiment 1

20m ³2 in individual accent breast jar, electric mixer and recycle pump are housed, add content 69% cationic etherifying agent to starch quality 8.05%, add starch quality 2.76%NaOH with flow velocity 4000L/h through circulating line, concentration is 2.25%NaOH solution, when PH to 11.8 the time, add the 1t tapioca (flour) earlier, then with the Sodium sulfate anhydrous.min(99) of adding in 10kg/ minute to starch quality 6.3%, adding remaining 15t tapioca (flour) control rate of feeding again is 100kg/ minute, PH is 11.6 in control, starch suspension concentration 24.2 Baumes.Be warmed up to 45 ℃ of reaction 8h then, cooling with concentration be in 8% the dilute hydrochloric acid with PH to 6.0, through washing, dehydration, drying, obtain finished product.

Embodiment 2

20m ³2 in individual accent breast jar, electric mixer and recycle pump are housed, add content 69% cationic etherifying agent to starch quality 8.5%, add starch quality 2.8%NaOH with flow velocity 4000L/h through circulating line, concentration is 2.25%NaOH solution, when PH to 11.8 the time, add the 1t W-Gum earlier, then with the Sodium sulfate anhydrous.min(99) of adding in 10kg/ minute to starch quality 5.75%, adding remaining 15t W-Gum control rate of feeding again is 100kg/ minute, PH is 11.5 in control, starch suspension concentration 23 Baumes.Be warmed up to 48 ℃ of reaction 9h then.Cooling is in 8% dilute hydrochloric acid and PH to 7.0 with concentration, through washing, dehydration, drying, obtains finished product.

Embodiment 3

20m ³2 in individual accent breast jar, electric mixer and recycle pump are housed, add content 69% cationic etherifying agent to starch quality 10%, add starch quality 3.0%NaOH with flow velocity 4000L/h through circulating line, concentration is 2.25%NaOH solution, when PH to 11.8 the time, add the 1t W-Gum earlier, then with the Sodium sulfate anhydrous.min(99) of adding in 10kg/ minute to starch quality 7.0%, adding remaining 15t W-Gum control rate of feeding again is 100kg/ minute, PH is 11.6 in control, starch suspension concentration 24 Baumes.Be warmed up to 48 ℃ of reaction 8h then.Cooling adds concentration and is in 8% the dilute hydrochloric acid and PH to 8.0, through washing, dehydration, drying, obtains finished product.

Embodiment 4

20m ³2 in individual accent breast jar, electric mixer and recycle pump are housed, add content 69% cationic etherifying agent to starch quality 11%, add starch quality 3.0%NaOH with flow velocity 4000L/h through circulating line, concentration is 2.25%NaOH solution, when PH to 12 the time, add the 1t tapioca (flour) earlier, then with the Sodium sulfate anhydrous.min(99) of adding in 10kg/ minute to starch quality 7.4%, adding remaining 15t tapioca (flour) control rate of feeding again is 100kg/ minute, PH is 11.6 in control, starch suspension concentration 25 Baumes.Be warmed up to 45 ℃ of reaction 8h then.Cooling with PH to 6.0, through washing, dehydration, drying, obtains finished product in the dilute hydrochloric acid.

Claims (2)

1. cationic starch producing method, it is characterized in that: concrete steps are:

(1) etherifying agent activation and accent breast: at normal temperatures, adding starch quality is that 2.3～11.5% content is 69% cationic etherifying agent 3-chloro-2-hydroxypropyl-trimethyl ammonium chloride, adding concentration with circulating line with 3000-4000L/h is that 2.25% sodium hydroxide solution is transferred pH to 11～12, add 5～10% starch, be 3.45～7.47% Sodium sulfate anhydrous.min(99) to add starch weight in 10kg/ minute then, add remaining starch again, control starch adding speed is 100kg/ minute, pH is controlled at 11.5～11.6, concentration control 23～25 Baumes;

(2) etherification reaction: heat up, react 8～12h down at 40～55 ℃;

(3) neutralization: with in 8～10% hydrochloric acid and to prepare pH be 6～8 neutral cation starch;

(4) washing, dehydration, drying obtain finished product.

2. cationic starch producing method as claimed in claim 1 is characterized in that: in can also be in (3) neutralization with 8～10% hydrochloric acid and preparation pH be 2～4 acidic cation starch.