JPH0873502A - Production of cationized starch - Google Patents

Abstract

PURPOSE: To provide a process for producing a cationized starch whereby starch is cationized by dry process using an entirely new cationizing agent without using an alkali catalyst by using a specific cationic resin compsn. as the cationizing agent. CONSTITUTION: Starch is compounded with a cationizing agent comprising an acid-sol. cationic resin compsn. which is a polycondensate obtd. by heating a dicyandiamide-formaldehyde mixture in the presence of ammonium chloride or sulfate. The resin compsn. is formed by thermally reacting 1mol of dicyandiamide with 1mol or lower of the ammonium salt and then condensing the reaction product with 2mol or higher formaldehyde. A cationized starch is formed merely by homogeneously mixing starch with an aq. soln. of the cationizing agent having a concn. as high as possible. Further, the reaction can be accelerated by heating at 40-60 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a cation-modified starch easily by a dry method. More specifically, an acid-soluble cationic resin composition obtained by a polycondensation reaction by heating in the presence of dicyandiamide / formaldehyde and ammonium chloride or ammonium sulfate as a cationizing agent is used as a cationic agent in dry starch in a natural state without a catalyst. It relates to a method for producing a cationized modified starch obtained by mixing and drying.

[0002]

2. Description of the Related Art A generally known method for cationizing starch is a wet method. The method is a method in which starch is suspended in water, sodium sulfate or sodium chloride is added as a swelling inhibitor for starch particles, caustic soda is added to make starch a sodium salt, and diethylaminoethyl chloride is added to this solution for reaction. However, since the starch obtained here is of the tertiary amine type, a large amount of cation-modified starch is produced by the method of adjusting the pH of the liquid to 3.0 to 4.0 after the reaction.

Another method for producing a cationized starch is to disperse the starch in an aqueous solution containing 2,3-epoxypropyltrimethylammonium chloride obtained from epichlorohydrin and trimethylamine as a cationizing agent and react with caustic alkali as a catalyst. However, in any method, after the reaction, it is filtered, washed with water, and then dried to be manufactured. However, recently, as patents which can be produced by a dry method by this method, Japanese Patent Publication Nos. 56-14681 and 59-5.
No. 2162 discloses the production method, but all of them use caustic as a catalyst. Further, as a non-catalytic method, a method which does not use caustic is disclosed in JP-A-6-87902, but it has not been put to practical use yet.

[0004]

It is known that the dry method is the most economical method for producing the cationized modified starch, but since the amount of the cationizing agent used is small, the dry method is used. However, the wet method is adopted because it is difficult to react the cationizing agent evenly.
In particular, cationization with diethylaminoethyl chloride is an ionic reaction and must be reacted as an alkali starch, so that it is difficult to produce by a dry method.

Further, a method of reacting 2,3-epoxypropyltrimethylamine ammonium chloride obtained from epichlorohydrin and trimethylamine with starch in the presence of an alkali catalyst to obtain a cationized modified starch is generally used. The reaction is a wet reaction in which starch is reacted in water in a dispersed state. There is a demand for a method for producing a cationized modified starch which is a dry method and is catalyst-free.

[0006]

Means for Solving the Problems As a result of studying the conditions necessary for the above reaction, the present inventors have found that a cationized modified starch with a completely new cationizing agent which is a dry method and does not require an alkali catalyst. The present invention was completed by discovering that The cationized modified starch obtained here can be said to be a completely new production method which is comparable to conventional cationized modified starch.

The compound used as the cationizing agent is not a novel compound, but has been conventionally used as a fixing agent for direct dyes.
It is an acid-soluble cationic resin obtained by heating reaction of formaldehyde with ammonium chloride or ammonium sulfate. This resin is a cationizing agent having no surface activity.

The reaction of dicyandiamide formaldehyde with ammonium chloride or ammonium sulphate involves reacting 1 mole of dicyandiamide with up to 1 mole of ammonium salt by heating and then condensing the reaction product with at least 2 moles of formaldehyde. The acid-soluble cationic resin obtained by

In addition, the cationizing agents which have been conventionally used are, when they are used, liberated from an acid salt by using caustic alkali to cause an ionic reaction, or by reacting with caustic alkali as a catalyst. Alkaline is unstable and prone to hydrolysis. However, the cationizing agent used in the present invention is stable and hardly decomposes even after mixing with starch and after the reaction, it is an easy-to-use cationizing agent.

In the method for producing the cation-modified starch according to the present invention, it suffices to mix the starch with an aqueous solution of the cationizing agent according to the present invention in a concentration as high as possible. The reaction temperature may be room temperature, but the reaction proceeds more quickly if heated to 40 to 60 ° C. It is known that the acid-soluble cationic resin obtained by the heating reaction of dicyandiamide formaldehyde with ammonium chloride or ammonium sulfate, the composition of the obtained product greatly changes depending on the ratio of the raw materials used and the reaction conditions.

The resin obtained in this reaction is in a pre-resin state, that is, in most of the pre-resinification steps, when the methylol compound is dehydrated and condensed into a resin, a part of the active groups are converted to -OH groups of starch. It may be crosslinked. The resin compound before the initial product of such a resin may be regarded as a reactive resin, and the reaction mechanism is considered to be a condensation reaction between a methylol compound and starch.

The starch used in the present invention is a common starch,
For example, any starch such as corn starch, potato starch, sweet potato starch, tapioca starch, wheat starch, rice starch, or sago starch obtained from sago palm can be used without any trouble. The water required for the reaction is not particularly concerned, and 10-18%, which is the water retained by the starch in the natural state, is sufficient, but in addition to this, the amount used to blend the cationizing agent into the starch as uniformly as possible. Dilution water is required.

To mix the cationizing agent and the starch, the starch is put in a powder mixer such as a kneader having an appropriate volume and stirred, and a 10 to 50% diluted water solution of the cationizing agent or a part of the water is added to methanol or ethanol. It can also be used as a diluent for a cationizing agent by replacing it with a lower alcohol such as. A small amount of this diluted solution is dropped or sprayed and added. Further, for 30 to 120 minutes so that the cationizing agent can be mixed uniformly,
Continue stirring. After the mixing is completed, the cationized modified starch can be obtained by drying at a temperature of 40 to 60 ° C. or simply by naturally drying. 1 to 1 in natural drying
It takes a drying time of 5 days, but there is no risk of decomposition unlike conventional cationizing agents. Next, the present invention will be described with reference to examples, but the present invention is not limited to these examples. In addition, all percentages shown in the examples are represented by weight percentage.

[0014]

The present invention differs from the conventional method for producing a cationized modified starch obtained by reacting starch with a cationizing agent, unlike corn starch, potato starch, sweet potato starch, tapioca starch, wheat starch, rice starch, sago. This is a method for producing a cationized modified starch obtained by simply mixing ordinary starch such as starch with dicyandiamide formaldehyde and an acid-soluble cationic resin obtained by a polycondensation reaction by heating in the presence of ammonium chloride or ammonium sulfate.

[0015]

[Example] Desktop type kneader for a laboratory (use capacity 200 m
Into l), 100 g of sago starch (nitrogen content 0.03% of dried matter, water content 12.8%) was added and stirred (rotation speed 25 rpm).
However, as a polycondensate of dicyandiamide / formaldehyde aqueous solution / ammonium chloride salt, Daifix D-10 (product of Daiwa Chemical Industry Co., Ltd .: Pure 51.
0%) 5.0 g and diluted water 5.0 g were applied to a small amount. After completion of the appropriate period, stirring was continued for another hour, then spread on paper and dried overnight to obtain cationized modified sago starch. After drying, place the sample in a 50 ° C incubator for 1 day, 3 days, 5 days, 1 day.
After storage for 0 days, each was thoroughly washed with methanol and the nitrogen content was measured. The results are shown in Table 1, and as confirmation of the cationic property, the treatment was carried out in an acidic dye solution, and the dye concentration in the residual solution due to dye adsorption was measured by colorimetry. The results are shown in Table 2.

[0016]

[Table 1]

[0017]

[Table 2]

Method for Measuring Nitrogen Content of Cationized Modified Starch About 5 g of the cationized modified starch was put into 100 ml of methanol, stirred well, and then filtered. After filtration, the sample was washed with the same amount of methanol and dried to obtain a sample for measuring nitrogen. The sample thus obtained was analyzed for nitrogen by the semi-micro Kjeldahl method (according to the 12th revised Japanese Pharmacopoeia) to determine the content of nitrogen.

Method for Measuring Cationization Degree by Adsorption of Dye on Cationized Modified Starch The cationized modified starch after washing with methanol is well ground in a mortar, and 1 g thereof is weighed in a 100 ml beaker. Add 5% of a 0.1% solution of Azorbinol 3GP as a dye solution.
Add ml and stir well with a glass rod for 1 minute, then add 50 ml
Immediately, add the distilled water mentioned above and filter immediately. This filtrate was subjected to color comparison with a photoelectric colorimeter (Model AE-11 Elma Photoelectric Co., Ltd.). The measurement was performed by setting T% of water to 100. As a control, the same treatment was applied to the non-cationized starch.

[0020]

According to the conventional method for producing cation-modified starch, the starch and the cationizing agent are mainly caustic, and the method of the present invention is used. It is a production method in which a cationized modified starch is obtained by simply mixing a solution of an acid-soluble polycondensate obtained by a heating reaction with ammonium or ammonium sulfate with dry starch.

Claims (1)

[Claims] 1. An acid-soluble cationic resin composition obtained by polycondensation reaction by heating reaction in the presence of ammonium chloride or ammonium sulfate in a mixture of dicyandiamide and formaldehyde, which is obtained by blending starch as a cationizing agent for starch. A method for producing a cationized modified starch, which comprises: