JPS60156701A - Preparation of cationic starch - Google Patents

Abstract

PURPOSE:To prepare a cationic starch, having a high substitution degree and useful as a paper strength improver, etc. in high yield, by reacting cyanoethylated starch with NH2OH in an aqueous system, and converting the terminal nitrile groups into amidoxime. CONSTITUTION:Cyanoethylated starch of formula I is reacted with NH2OH or a salt thereof, e.g. sulfate or hydrochloride, in an aqueous solution or slurry or a slurry in a hydrophilic solvent preferably at 50-100 deg.C at neutral - weakly alkaline pH for 3-6hr to give the aimed cationic starch of formula II or III. The cyanoethylated starch of formula I is obtained, e.g. by solubilizing starch of formula IV in water, adding 5-10mol%, based on the starch, NaOH or KOH thereto, and heating the resultant mixture at about 60 deg.C in the presence of acrylonitrile.

Description

Detailed Description of the Invention The present invention involves reacting cyanoethylated starch obtained by adding acrylonitrile to starch in the presence of an alkali catalyst with hydroxylamine or its salts in an aqueous solution or slurry form or in a slurry form in a hydrophilic solvent. This invention relates to a method for producing cationized starch by converting the terminal nitrile group into an amidoxime.

In the paper industry, cationized starch is used as a paper direction agent, filler retention agent, and P waterability improver by being added internally during papermaking, and in the textile industry, it is used as a warp sizing agent, a finishing agent, and as a flocculant and Various uses such as emulsifiers are known, but the conventional method for producing them is to prepare alkaline starch in the form of a slurry or paste in the presence of a strong alkali, for example, with a haloalkylamine such as 2-dimethylamine ethyl chloride or 3-dimethylamine. Reaction with an aminochlorohydrin compound such as chloro-2-hydroxyglobil dimethylamine or with a glycidylamine such as N-(2,3 epoxyglobil) diethylamine in the presence of a catalytic amount of alkali. methods are commonly used.

It is also useful to react starch with alkali metal salts of cyanamide or alkaline earth metal salts in alkaline conditions.)
Methods of producing cationized starch are also known, but this product suffers from stability problems when left as a paste.

t 7'c Schiff / A method is proposed in which monotylated starch is reduced with lithium aluminum/N hydride to cationize it, but this method is difficult to implement in an aqueous system.

In the present invention, by reacting cyanoethylated starch with hydroxylamine or its salt in an aqueous system, the terminal nitrile group is removed from the amide oxide in an almost neutral region, and a high degree of substitution of 10 mole or more based on starch is obtained with high yield. A method for producing cationized starch is provided. The Taisho amidoximation reaction is a well-known method for modifying acrylonitrile polymers, and is shown in the reaction formula below.

-OH, -OH- In the production of cationized starch by conventional methods, the cationization yield was poor, and it was particularly difficult to obtain products with a high degree of substitution.

Cyanoethylated starch is made by solubilizing starch in water by a known method, and adding 5 to 1 ml of caustic soda or caustic potash to the starch.
It is obtained by adding 0 molt and heating to around 6,000 ℃ in the presence of a predetermined amount of acrylonitrile. Granular products can also be obtained by dipping starch in alkaline water, reacting it in the same manner as acrylonitrile, collecting unreacted acrylonitrile, and then drying it.The reaction formula is as follows.

The degree of OH cyanoethylation depends on the reaction temperature, reaction time and molar ratio of acrylonitrile to starch and the amount of alkali. Especially when carried out in strong alkalinity, acrylonitrile is nitrile trisnorobyl nitrile, β
, β'-oxydipropyl 3- 7.5. ), the apparent consumption rate of acrylochitrile increases, but the reaction rate of starch cyanoelation and chilling decreases. In a 1:1 aqueous solution of starch, add 5 mol of NaOH to starch and 10 mol of acrylonitosol to powder.
0-! 70'O-t' 3 Il! When the mixture is stirred for 5 to 5 hours, a degree of cyanethylation of about 70 to 785 degrees can be obtained. .

, If I were to just use the name of the amidoxime group, I would say that hydro-, doro-, and xylamine are not commercially available as monomers, so
Use hydrochloride instead of sulfate. For use, the free hydroxyl, amino acid, is added to the aqueous salt solution described above. t
7th, equivalent or slightly less caustic saw-1,,,'
f! , sex potash, 1. , open. Burnt sodium carbonate, carbonic power +4. ．． 1. ;Ru. Then, a solution containing an organic amine such as ethylene diamine is used. The reaction temperature is 5
0? o is 1' et al. 100'0. Up to 1. Reaction time is 3 to 6 hours
Time □ r! ! Degree, narrowness, necessity. During this time, the pH remains neutral or weakly alkaline.

The reaction solution thus obtained is cationized by the following method.
When e is measured, a cationization rate of 60 to 70% is obtained compared to 4 for cyanoethylated starch.

The degree of cationization of the obtained cationized starch was measured by colloid titration. That is, a sample equivalent to 10 μm was taken and diluted with 100 μl of distilled water. Titrate with /400 polyvinyl sulfate potassium using toluidine blue as an indicator. In this case, the amount of potassium polyvinyl sulfate consumed is proportional to the amount of cations in the sample. Therefore, in this case, titration (only the electrolytic colloid that contributes to the measurement is the amidoxime compound of the low molecular weight monomer acrylonitrile, etc., but only the cyanoethylated amidoxime compound of the powder is measured. And now it happens.

It is thought that the cationized starch obtained by pressing 9 and 9 has the following structure.

, , :::', :1:l” , : , , , :,
, O.M.

When added internally during paper making, this material not only exhibits significantly improved paper strength by 1 to 10% compared to conventional cationized starch, but also
It can be said to be significantly superior to conventional cationized starch, as it can obtain paper strength values comparable to those of polyacrylamide-based paper strength agents, and improves furnace water resistance during paper making.

EXAMPLES Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited thereto.

Reference example Method for producing cyanethylated starch.

(Reference Example 1) Oxidized starch (purity 87%) 46 f was placed in a backflow cooler,
Place in a tri-lokolben equipped with a thermometer and stirrer, and add 1 part distilled water.
Add 5Q Wt, N-NaOH12,5- and heat and stir at 70°0 for 1 hour to dissolve. Added NaOHii
is 5 mol of starch. Transfer the solution to a glass autoclave equipped with a stirrer, and add acrylonitrile 13
Add v (100 mol % based on starch) and stir at 70°0 for 5 hours. After the reaction is completed, unreacted acrylonitrile is quantified by the dodecyl mercaptan method. In this case, the reaction rate of acrylonitrile was 83.0%.

(Reference Example 2) Cornstarch (purity 87%) 46F was added to the above trilocolben, and 320 ml of distilled water and 5N-NaO were added.
Add H32rail (10 molt to starch) and 3 m/(4 molt to starch) of sodium hypochlorite (12% chlorine) and dissolve by heating and stirring at 50°C for 2 and a half hours. After dissolution, 5N-H, 5o429- is added to neutralize a portion of the alkali, and the amount of remaining alkali is adjusted to 6 moles of starch. This solution was transferred to the above autoclave, and acrylonitrile 1
Add 3v (100 mol of starch) and heat and stir at 70°0 for 3 hours. The reaction rate of acrylonitrile is 57.5
%Met.

(Reference Example 3) 46 tons of oxidized starch (purity 87%) was placed in the same three-necked flask as in (1), and 340 m of distilled water and ``N-NaOH20
ml (8 moles of starch) was added and dissolved by heating at 60'O for 1 hour, and this was transferred to a glass autoclave.
Add 10v of acrylonitrile (76.5 mol relative to starch) and heat and stir at 0.000C for 3 hours. After the reaction was completed, unreacted a7-crylonitrile was measured by the dodecyl mercaptan method, and the reaction rate to starch was 53.0%.

Example 1 of the method for producing amidoxime-modified starch.Cyanethylated starch paste liquid 100 starting from the oxidized starch produced in Reference Example 1 for the production of cyanethylated starch.
t (18.6% product as starch) was placed in the three-loaf flask, and hydroxylamine sulfate (NH, OHTH, 8
04) 9.49 (100% starch #%) 5N-NaOH207! (For hydroxylamine (a)
Add the solution dissolved in mol.), heat and stir at 70'O for 5 hours, and after the reaction is complete, take a sample equivalent to 10 ml of starch, dilute it with distilled water, and dilute it with N/4oo potassium polyvinyl sulfate solution. A titration L value of 12.5 was obtained using toluidine purpurate as an indicator. This value is 50.4 for starch.
% reaction rate.

Example 2 Cyanoethylated starch (starting from raw starch) prepared in Reference Example 2 100 y of starch (9.3 y as starch)
In the same manner as in Example 1, 4.8 f of hydroxylamine sulfate (100 mol q6 of starch) was heated and stirred for 50 m of N-NaOH (4 f85 of hydroxyl sulfate) in the same manner as in Example 1. After the reaction was completed. A sample equivalent to 10 μ of starch was taken, and the amount of cations was measured by colloid titration in the same manner as in Example 1. The titration value was 8.4-, which was 33.9 against starch.
% reaction rate.

Example 3 Starting from the raw starch produced by the method of Reference Example 2, 100 t of cyanoethylated starch paste liquid (9, 3 t as starch) was prepared.
%) was placed in the same three-ring flask as in Example, and a solution of 2.4 f of hydroxylamine sulfate (anti-starch) dissolved in 25 ml of N-NaOH (85 mol % relative to hydroxylamine) was added and the mixture was heated to 70'0. The mixture was heated and stirred for 3 hours. After the reaction was completed, colloid titration was performed in the same manner as in Example 1. The titration value is 4.4- and the reaction rate for starch is 1.
It was 7.7 excellent.

Example 4 Cyanoethylated starch paste liquid io obtained by the method of Reference Example 3 above
o t (9.9% product as starch), 4.2 f of hydroxylamine salt (NHIOH-HOj) (same mole as the acrylonitrile added in the above (A) (3) production of thick liquid) in 50 ml of N-NaOH ( A solution dissolved in Hydroxylamine Co., Ltd. (Molti) was added, and the mixture was placed in the same three-ring flask as described above and reacted at 70°0 for 3 hours. After the reaction was completed, colloid titration of the amount of cations was carried out, and starch 1
A value of 7.1-/011 g was obtained. This is against starch 28.
This corresponds to a reaction rate of 8%.

Reference example paper strength test freeness 550 +d 01! 'B's site IJUKP
Paper was made using a TAPPI standard machine under the conditions of adding bread soil of N = 3% and having a basis weight of 50 t/m2.

Drying conditions are 120°/2 minutes. As a control, a comparison was made with a commercially available cationic starch (3-chloro-2-hydroxyglobil dimethylamine is reacted with starch and then classified). Paper strength was measured using a bursting strength tester.

The results were as shown in the table below.

According to this table, the present invention is applied. It is understood that the paper strength effect of cationized starch is remarkable.

Patent applicant: Kyoritsu Organic Industrial Research Institute A-

Claims (1)

[Claims] '77 A method for producing cationized starch by reacting noethylated starch with hydroxylamine or its salt in an aqueous system and converting the terminal IJ group into amidoxime.