A kind of radiation causes the preparation of cationic starch method
Technical field
The invention belongs to field modified starch technologies of preparing such as papermaking, spinning sizing agent, be specifically related to a kind of radiation and cause the preparation of cationic starch method.
Background technology
Cationic starch is the various organic amine compounds that contain halogeno-group or epoxy group(ing), carries out etherification reaction with hydroxyl in the starch molecule and a kind of starch ethers analog derivative that contains amino and have positive charge on nitrogen-atoms of generating.Cationic starch is easily combined closely with electronegative fiber fines, filler because it has positive charge; The gelatinization point of cationic starch is low, and slurries stability is high, and good film-forming property is good with the affinity of fiber, thereby uses paper making wet part widely and make retention filtration adjuvant and toughener, and the sizing agent of textile warp.
But the cationic starch substitution value that a few days ago is applied to paper industry and spinning sizing agent industry is generally 0.01~0.07, belongs to the low degree of substitution cationic starch, and this has limited the more wide application of cationic starch in fields such as papermaking, spinning sizing agents to a certain extent.Causing cationic starch substitution value major cause on the low side is the restriction of cationic starch production technique.At present, the production method of cationic starch generally has 4 kinds, i.e. water solvent method, organic solvent method, dry method method and semidrying.Advantages such as product impurity is few though the water solvent method has, steady quality have certain sewage to discharge, and this method are unsuitable for preparing cationic starch with high substitution degree.Therefore organic solvent method exists shortcomings such as production cost height, poor stability, the large-scale reactor of needs owing to used a large amount of organic solvents.The advantage of dry process is that cationics needn't be made with extra care, needn't add anti-gelling agent, needn't carry out aftertreatment, not have the three wastes substantially, but this method reaction conversion ratio is low, because of being solid state reaction, apparatus and process is required than higher.Semidrying occurs after wet method and dry process, and this method still needs alkali lye as catalyzer, has defective at aspects such as environmental pollution and quality producies.
Summary of the invention
The object of the present invention is to provide a kind of radiation to cause the preparation of cationic starch method, this method non-environmental-pollution, production technique is simple, cost is low.
To achieve these goals, technical scheme of the present invention is: a kind of radiation causes the preparation of cationic starch method, it is characterized in that it comprises the steps:
1), will add cationic etherifying agent in the ative starch, the add-on of cationic etherifying agent is 1%~100% of an ative starch quality, stir, mixture;
2), mixture is placed
60Carry out irradiation in the Co irradiation field, under aerobic conditions, initiation reaction, according to different radiation dose rates, irradiation dose is controlled by the control irradiation time (different irradiation sources is different according to the different irradiation times of irradiatometer dose rate, satisfying total irradiation dose gets final product), make irradiation dose at 3KGy~15KGy, get blend;
3), the blend that obtains behind the irradiation is carried out aftertreatment processing: the baking oven drying that blend is placed 130~150 ℃ or 180~200 ℃, stir, so that peroxide breakdown, free radical fully reacts, last crushing screening, cross 100 mesh sieves, promptly get cationic starch, substitution value is 0.01~0.47.
Described cationic etherifying agent is quaternary ammonium salts or tertiary ammonium salt type organic.
Described cationic etherifying agent is epoxypropyl trimethylammonium bromide or epoxypropyl trimethylammonium chloride ammonium etc.
The add-on of described cationic etherifying agent is 3%~55% of an ative starch quality.
Described ative starch is corn ative starch, wheat ative starch, potato ative starch, cassava ative starch or Ipomoea batatas ative starch etc.
Described ative starch water ratio is 12%~16%.
The invention has the beneficial effects as follows: at Co
60Under the high-energy radiation condition, ative starch mixes mutual radiation with the positively charged ion etherificate, and the epoxy bond in the cationic etherifying agent is opened, and forms free radical on the epoxy bond that disconnects, and polyreaction to a certain degree also can take place wherein a part of etherifying agent; Ative starch is under radiation condition, with degraded and the oxidation that takes place to a certain degree, on starch molecule, produce free radical, and in blend, form certain density superoxide, by the control irradiation dose, molecular weight that can the stabilizing starch molecule is at certain level, and the cationic starch viscosity that guarantees preparation is at 6~18mpas.Adopt aerobic mutual radiation technology, in the irradiation process, a part of etherifying agent combines with starch by free radical reaction, generates starch ethers, other unreacted etherifying agents are reacted in follow-up high-temperature stirring process, make that the efficient in the whole process of preparation reaches more than 80%.Cause the preparation cationic starch with respect to the traditional chemical method, because the free radical uniform distribution that irradiation forms, and the quantity of free radical height very, so can on the basis of adjusting irradiation and aftertreatment complete processing, realize the cationic starch of different degree of substitution as required.Because the present invention does not relate to chemical reagent such as acid, alkali, and does not need water washing, can accomplish environmentally safe, production technique is simple, and is with low cost.
Description of drawings
Fig. 1 is a process flow sheet of the present invention
Embodiment
In order to understand the present invention better, further illustrate content of the present invention below in conjunction with embodiment, but content of the present invention not only is confined to the following examples.
Embodiment 1:
As shown in Figure 1, in one 1000 milliliters beaker, add 285 gram corn ative starchs, the ative starch water ratio is 14%, take by weighing 15 gram cationic etherifying agent (2,3-epoxypropyl trimethylammonium bromide) liquid and pour in the ative starch, with the abundant blended under agitation thing of glass stick 30 minutes, make the full and uniform mixing of mixture, preparation quality per-cent is the mixture of 5% etherifying agent; Then mixture is packed into polyethylene from sealing in the polythene bag, seal; The polythene bag that mixture is housed is placed
60The Co irradiation field (
60CO-gamma-ray irradiation field) carry out irradiation in, under aerobic conditions, the control irradiation dose is 5KGy; Blend behind the irradiation is poured in the sealed vessel, placed 140 ℃ constant temperature oven, drying 2 hours, cooling at normal temperatures then, crushing screening is crossed 100 mesh sieves, and packing can make heating gelatinization type cationic starch products.Substitution value DS=0.025, the viscosity stability of product.
Embodiment 2:
In one 1000 milliliters beaker, add 285 gram corn ative starchs, the ative starch water ratio is 14%, take by weighing 15 gram cationic etherifying agents (2,3-epoxypropyl trimethylammonium chloride ammonium) liquid is poured in the ative starch, with the abundant blended under agitation thing of glass stick 30 minutes, make the full and uniform mixing of mixture, preparation quality per-cent is the mixture of 5% etherifying agent content; Then mixture is packed into polyethylene from sealing in the polythene bag, seal; The polythene bag that blend is housed is placed
60Carry out irradiation in the Co irradiation field, under aerobic conditions, the control irradiation dose is 5KGy; Blend behind the irradiation is poured in the sealed vessel, placed 190 ℃ constant temperature oven, drying 2 hours, cooling at normal temperatures then, the crushing screening packing can make cold water solubles type cationic starch products.Substitution value DS=0.025.
Embodiment 3:
Get water ratio and be 13% potato ative starch 291 grams, add 2,3-epoxypropyl trimethylammonium chloride ammonium cation etherifying agent 9 grams stir, mixture; Mixture is placed
60Carry out irradiation in the Co irradiation field, under aerobic conditions, initiation reaction is controlled irradiation dose by the control irradiation time, makes irradiation dose at 15KGy, gets blend; Blend is placed 150 ℃ baking oven drying, stir, so that peroxide breakdown, free radical fully reacts, and pulverizes at last, crosses 100 mesh sieves, promptly gets cationic starch, and substitution value is 0.014.
Embodiment 4:
Get water ratio and be 16% cassava ative starch 165 grams, add 2,3-epoxypropyl trimethylammonium chloride ammonium cation etherifying agent 135 grams stir, mixture; Mixture is placed
60Carry out irradiation in the Co irradiation field, under aerobic conditions, initiation reaction is controlled irradiation dose by the control irradiation time, makes irradiation dose at 10KGy, gets blend; Blend is placed 150 ℃ baking oven drying, stir, so that peroxide breakdown, free radical fully reacts, and pulverizes at last, crosses 100 mesh sieves, promptly gets cationic starch, and substitution value is 0.47.
The bound value and the interval value of the add-on of cationic etherifying agent of the present invention, and the bound value of irradiation dose and interval value can both realize the present invention, just do not enumerate embodiment one by one at this.