JPH089654B2 - Method for preparing polysaccharide-based alkali metal salts of polyacrylic acid - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a method for preparing alkali metal salts of polyacrylic acid based on polysaccharides as dispersants. According to the invention, alkali metal salts of polyacrylic acid based on polysaccharides which have both good chelating ability for heavy metal ions and biodegradability by microorganisms are grafted with acrylic monomers onto polysaccharides in aqueous alcohol solution. A high yield is obtained by reaction followed by neutralization with aqueous sodium hydroxide solution.

Generally, detergents are linear alkyl benzene sulfonates,
It consists of multiple components such as sodium tripolyphosphonate, alkali metal salts of polyacrylic acid, sodium silicate, sodium carbonate, perfumes and dyes. Among these, sodium triphosphonate, which has a good chelating ability, promotes small streams and malnutrition in rivers and pollutes water. The alkali metal salt of polyacrylic acid as a dispersant has a low chelating ability for heavy metal ions and a low biodegradability by microorganisms.

In order to increase the chelating ability and biodegradability of alkali metal salts of polyacrylic acid, graft copolymerization of acrylic monomers onto polysaccharides was performed [J. Appl. Polym. Sci., 32
(1986) 4971: Eur. Polym. J., 25 (1989) 423]. The results showed that the grafting yield was low due to the poor solubility of polysaccharides in aqueous solution at the reaction temperature of 25-70 ℃.

To improve these problems, highly reactive starch / thiolation [Tappi, March, 56 (1973) 97], irradiation [J.App
L.Polym.Sci., 26 (1981) 2073], acrylated [J.Poly.
m.Sci., Part-A, 5 (1965) 1031] and the like were used in the grafting reaction, and several methods were proposed in which the reaction was carried out at high temperature [Ger Offen., 2, 436, 555 (1976)]. Redox catalysts such as cerium ammonium salts, Penton's reagent and manganese sulfate are used [J. Polym. Sci., 23 (197
1) 229] Other methods were also introduced. In particular, it has been difficult to carry out the graft reaction of acrylic monomers on polysaccharides with radical initiators [J.Appl.Polym.sci., 23 (1971)
229]. This method was not desirable due to the low yield of grafting at reaction temperatures of 25-70 ° C.

SUMMARY OF THE INVENTION It is an object of the present invention to use an alcohol as a reaction diluent for a polysaccharide and to improve the yield of grafting by the graft reaction of an acrylic monomer onto a polysaccharide in the presence of a redox catalyst in aqueous alcohol solution. It consists in preparing a high low molecular weight copolymer.

The alkali metal salt of polyacrylic acid based on the polysaccharide of the present invention is prepared by heating the polysaccharide with an aqueous alcohol solution to dissolve it, and gradually cooling it to obtain an acrylic monomer and / or
Alternatively, a mixture of a vinyl comonomer and a redox catalyst is added, the mixture is stirred at a suitable temperature for several hours, then the hydroalcoholic solution is distilled off under reduced pressure and neutralized with an aqueous sodium hydroxide solution.

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, an alkali metal salt of polyacrylic acid based on a polysaccharide dissolves the polysaccharide in 0.5 to 95% aqueous alcohol at 60 to 90 ° C. for 0.5 to 5 hours and gradually Cooled, and a mixture of acrylic monomer and / or vinyl comonomer and redox catalyst is added under nitrogen atmosphere,
It is prepared in high yield by stirring the mixture at 25-70 ° C. for 2-40 hours, then distilling the hydroalcoholic solution at 60 ° C. under reduced pressure and neutralizing with sodium hydroxide-aq.

The alcohol as the reaction diluent in the present invention is used to bring the acrylic monomer into good contact with the polysaccharide in an aqueous solution to reduce the molecular weight of the product.

Alcohols are normal or isoalcohols having 3 to 9 atoms, such as propanol, butanol, pentanol, hexanol, heptanol, octanol, isopropanol, isobutanol, isohexanol and isoheptanol, one or more. A mixture is chosen. The polysaccharide was then dissolved by the alcohol in the graft copolymer of acrylic monomer onto the polysaccharide. The yield of the grafting reaction using alcohol was very high. The molecular weight of the product was accurately adjusted by the chain transfer reaction generated by the alcohol solvent.

Alcohol was used in 0.5-95% aqueous solution. Reactant solutions below 0.5% are not homogeneous and more viscous. A 95% or more solution has a low viscosity and requires a lot of energy to recover alcohol.

The acrylic monomers used in the present invention are acrylic acid, methacrylic acid, maleic anhydride and fumaric acid.

And the vinyl comonomers are methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, methyl methacrylate, hydroxyalkyl methacrylate, acrylonitrile, acrylamide and 4-vinyl pyridine. In the present invention, one kind or two or more kinds of these vinyl comonomers can be used.

These monomers are used to maintain the chelating ability to solubilize the polysaccharide and are used at 20-700% by weight of the amount of polysaccharide used. Below 20% by weight of the reactant solution is not homogeneous, above 700% by weight it is not possible to adjust the chelating capacity for heavy metal ions.

Further, the polysaccharides used in the present invention are starch, cellulose and their derivatives. That is, they are cereals, potatoes, wheat, sweet potato and rice starches, and aldehydes, alkyl ethers, oxyalkyls,
Modified starches containing hydroxyethyl ether, aminoethyl ether, cyanoethyl ether and carboxymethyl groups, and alkyl ethers, organic acid esters, cellulose derivatives containing hydroxy and carboxymethyl groups.

The oxidation catalyst used in the present invention is hydrogen peroxide,
Ascorbic acid, tert-butyl hydroperoxide, di-te
rt-Butyl hydroperoxide, dicumyl peroxide, cumene hydroperoxide, 2,5-dimethyl-hexyl-2,5-dihydroperoxide, diisopropylbenzene peroxide, 2,5
-Dimethylhexyl-2,5- (peroxybenzoate), di-tert-butyl peroxyphthalate, tert-
Butyl peroxyacetate, tert-butyl peroxy isopropyl carbonate and the like. These are 1
One kind or a mixture of two or more kinds is used.

The reducing catalyst used in the present invention is potassium persulfate, potassium permanganate, potassium perchromate, iron ammonium sulfate, N-cyclohexylbenzothiazole-2-
Sulfonamide, N, N 'dimethyl-p-toluidine, N,
N'-diethyl-p-toluidine, N, N'-diisopropyl-p-toluidine, butylamine, N, N'-dimethylaniline, bis (phenylsulfonmethyl) amine, bis (p-tolylsulfonmethyl) amine, N- Methyl-
Bis (p-tolylsulfonmethyl) amine, N-ethyl-bis (p-tolylsulfonmethyl) amine, N-ethanol-bis (p-tolylsulfonmethyl) amine, N
-Phenyl-p-tolylsulfone methylamine, N-phenyl-N-methyl-p-tolylsulfone methylamine, bis (p-tolylsulfonemethyl) ethylenediamine, N- (p-chlorophenyl) -p-tolylsulfone methylamine , N- (iso- or p-carboethoxyphenyl)-(p-tolylsulfonmethyl) amine, o
-Benzoxulfamide, phthalamide, sulfamide benzoate, hydrazine acetate, thiourea, N, N'-dimethyl-p-toluidine, N, N'-dimethyl-o-toluidine, N, N'-dicyclohexyl-thiourea , Acetylthiourea, tetramethylthiourea, mercaptobenzothiazole, 2-triazole-3-diol, and mercaptobenzimidazole. These use 1 type or a mixture of 2 or more types.

The catalyst used in the present invention is used at 0.005 to 0.5 mole percent of the amount of acrylic and vinyl comonomers used, and one or a mixture of redox catalysts is selected. If these are used in an amount of 0.0005 mol or less, there is no effect, and if they exceed 0.5 mol, the grafting yield is reduced by the production of a large amount of homopolymer.

The alkali metal salt of polyacrylic acid based on the polysaccharide prepared in the present invention has a viscosity of 50 to 10,000 cps. Even when using hard water, they show a good dispersing effect and prevent the precipitation of heavy metal ions in aqueous solution. Further, since these polysaccharide components have high biodegradability, they exhibit good biodegradability by microorganisms.

Therefore, these are extremely useful dispersants having both chelating ability and component degradability.

The following example illustrates how to apply the principles of the invention,
It does not limit the range.

Examples 1-10 Two liters of 2.6-10.6% aqueous isopropanol or butanol and 32.4 g (0.2 mol) -129.6 g (0.8
Mol) of cereal starch was added to a reactor with a reflux condenser, heated to 70 ° C. for a homogeneous solution and then gradually cooled to 40 ° C. Then, 14.4g (0.2mol) -57.6
g (0.8 mol) acrylic acid, 8.6 g (0.1 mol) ~ 17.2 g
(0.2 mol) methacrylic acid, 10 g (0.1 mol) to 20 g (0.
2 mol) of ethyl acrylate and kalimu persulfate [9.99 g (0.037 mol)] and hydrogen peroxide [1.97 g (0.0
58 mol)] and the mixture was stirred at 40 ° C. for 9 hours.

The aqueous alcohol solution was distilled off under reduced pressure, and the reaction product was neutralized with 8 g (0.2 mol) to 32 g (0.8 mol) of an aqueous sodium hydroxide solution to obtain a viscous liquid (solid content of 40% by weight).
The physical properties of the product are shown in Table 1.

Comparative Examples 1-9 2 liters of distilled water, 3 for the same reaction as the above example
2.4g (0.2mol) to 129.6 (0.8mol) cereal starch, 14.4g
(0.2 mol) to 57.6 g (0.8 mol) acrylic acid, 8.6 g
(0.1 mol) to 17.2 g (0.2 mol) methacrylic acid, 10 g
(0.1 mol) ethyl acrylate, and potassium persulfate [9.99 g (0.037 mol)] and hydrogen peroxide [1.97 g
(0.058 mol)] was added and heated to 70 ° C to form a homogeneous solution, then gradually cooled to 40 ° C.

The mixture was stirred at 40 ° C. for 6 hours. The aqueous solution was distilled under reduced pressure, and the reactant was neutralized with 8 g (0.2 mol) to 32 g (0.8 mol) of sodium hydroxide aqueous solution to obtain a viscous liquid (solid content of 40% by weight). The physical properties of the product are shown in Table 2.

In Tables 1 and 2, the chelating ability ¹⁾ of the product is shown in Japanese Patent Publication Nos. 52-4510 (1977) and 52-9005 (197).
It was measured by the test method of 7). And biodegradable
²⁾ was measured by the Miller test method [Anal. Chem., 31 (1959) 426].

That is, 3000 IU / ml of α-amylase enzyme is 4% (w / v)
Was added to the solid sample of, and allowed to stand for 20 minutes at 45 ° C and 5 minutes in boiling water. The extinction coefficient of the solution at 550 nm was measured by the dinitrosalicylic acid method, and the higher the extinction coefficient, the better the biodegradability by the enzyme.

Front Page Continuation (72) Inventor Kim Yang Eun, Republic of Korea Taejeong 300-120, Dong-Guk, Young-Gun-Dong 297, Dugong Apart 142-203

Claims (3)

[Claims] 1. A polysaccharide is dissolved in alcohol in the temperature range of 60 to 90 ° C. for 2 to 40 hours to obtain an acrylic monomer and / or
Or a polysaccharide-based polyacrylic resin characterized by adding a mixture of a vinyl comonomer and a redox catalyst for the grafting reaction, then distilling the hydroalcoholic solution under reduced pressure and neutralizing with aqueous sodium hydroxide solution. A method for preparing an alkali metal salt of an acid. 2. A process according to claim 1, wherein the alcohol is a normal or isoalcohol of 3 to 9 carbons and is used in a 0.5 to 95% aqueous solution. 3. The method according to claim 1, wherein the grafting reaction is carried out at 25 to 70 ° C. for 2 to 40 hours under a nitrogen atmosphere.