JPS6334882B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for cationizing acrylic acid hydrazide polymer compounds. More specifically, the present invention relates to a method for obtaining a cationized acrylic acid hydrazide polymer compound that behaves as a cationic polymer even in a neutral solution or in a diluted state. Conventionally, water-soluble polymers containing acrylic acid hydrazide units in their polymer chains behave as cationic polymers in acidic aqueous solutions due to their acid hydrazide groups; For example, as previously disclosed in JP-A No. 55-3440, by treating the acrylic acid hydrazide polymer compound with a water-soluble inorganic salt of an alkaline earth metal, it is possible to reduce the pH of the aqueous solution to less than 3.5. It can be cationized even at pH 3.5 or around neutrality, and under such conditions the problem of equipment corrosion in the paper manufacturing industry, which uses iron-based equipment, has been solved. However, even with this method, as seen in the examples in the above-mentioned publication, cationization is possible unless the alkaline earth metal is present in an amount of 1/2 mole or more per mole of acid hydrazide groups in the acrylic acid hydrazide polymer compound. Furthermore, it has the disadvantage that cationization becomes low in a diluted state. This is considered to be due to the low chelate stability constant between the acrylic acid hydrazide polymer compound and the alkaline earth metal ion. Therefore, the present inventors have conducted intensive research to improve the above-mentioned drawbacks, and as a result, we have developed an aqueous solution by allowing heavy metal ions to act on acrylic acid hydrazide-based polymer compounds instead of water-soluble inorganic salts of alkaline earth metals. It is possible to cationize more strongly than conventional methods using hydrochloric acid, etc., not only when the PH is less than 3.5, but also at PH3.5 or neutral, and even in the alkaline range, and even at low concentrations, cationization can be achieved by using heavy metal ions. They discovered that this is possible and that cationization occurs even in a diluted state, leading to the completion of the present invention. That is, the present invention is based on the general formula (): (In the formula, X is a hydrogen atom or a methyl group, and A
is an acrylamide, methacrylamide, acrylic ester or methacrylic ester unit, B is a monomer unit copolymerizable with acrylamide, methacrylamide, acrylic ester or methacrylic ester, l, m and n are 0 mol% The present invention relates to a method for cationizing an acrylic acid hydrazide polymer compound, which is characterized by causing a heavy metal ion to act on the acrylic acid hydrazide polymer compound having the following relationship: <l≦91 mol% l+m+n=100 mol%. In the cationization method of the present invention in which heavy metal ions are applied to the acrylic acid hydrazide polymer compound, even if the pH of the aqueous solution of the acrylic acid hydrazide polymer compound is 3.5 or around neutral, the pH can be reduced to 3.5 using conventional hydrochloric acid or the like. Compared to the method in which cationization is performed by reducing the amount of
Therefore, when cationizing acrylic acid hydrazide-based polymer compounds and using them for purposes such as size fixing agents, paper strength enhancers, and flocculants, problems such as equipment corrosion are less likely to occur, and the effects are also large. There is. In the cationization method of the present invention, the cationization mechanism of an acrylic acid hydrazide polymer compound by heavy metal ions is expressed by the formula (): As shown in the figure, it is thought that the acid hydrazide group forms a coordination bond with the heavy metal ion in the keto form, and as a result, the acrylic acid hydrazide-based polymer compound exhibits cationic properties. In the acrylic acid hydrazide polymer compound () used in the present invention, the acrylic ester providing the monomer unit (A) is preferably, for example, acrylic acid methyl ester, ethyl ester, butyl ester, 2-ethylhexyl ester, etc. can give. Also monomer unit (A)
Preferred examples of the methacrylic acid ester that give methacrylic acid include methyl ester, ethyl ester, and butyl ester of methacrylic acid. Examples of the monomer providing the monomer unit (B) include vinyl chloride, vinylidene chloride, vinyl acetate, butadiene, styrene, acrylonitrile, acrylic acid, maleic anhydride, and the like. The acrylic acid hydrazide polymer compound () may be a block type, alternating type, or random type polymer, and this polymer compound is usually a homopolymer or copolymer of acrylamide, methacrylamide, acrylic ester or methacrylic ester, or A copolymer of these monomers and a monomer copolymerizable with them, or a partial hydrolyzate thereof, is mixed with hydrazine in an amount of 0.1 to 30 moles of acrylamide, methacrylamide, acrylic ester, or methacrylic ester unit in the polymer chain. Obtained by heating reaction with hydrate. The acrylic acid hydrazide polymer compound () is a reaction product of the copolymerizable monomer and hydrazine hydrate (for example, when the copolymerizable monomer is vinyl acetate, the monomer unit (B) is a reaction product of the copolymerizable monomer and hydrazine hydrate). In some cases, the acetoxy group of the vinyl acetate unit in the copolymer is hydrolyzed by hydrazine hydrate and converted to a hydroxyl group, and in this case, the copolymer may contain a vinyl alcohol unit. In addition, even if some crosslinking occurs between acid hydrazide groups or between acid hydrazide groups and ester or amide groups within or between polymer molecules, the resulting acrylic acid hydrazide polymer This is acceptable as long as the compound is water-soluble. The acrylic acid hydrazide polymer compound () preferably exhibits an intrinsic viscosity [η] in the range of 0.1 to 28 in an aqueous solvent at 25°C. Heavy metal ions used in the present invention include, for example, mercury, copper, silver, nickel, iron, lead, cadmium, zinc, cobalt, and manganese ions, but zinc ions and iron ions are particularly preferred from the economical and toxicity standpoints. preferable. These heavy metal ions may be used alone or in combination of two or more. These heavy metal ions account for 1/50 to 1/2 (mole ratio), preferably 1/30 to 1/4 (mole ratio) of the number of moles of acid hydrazide groups in the acrylic acid hydrazide polymer (). used. There is no problem even if heavy metal ions exceed 1/2 (mole ratio), but the degree of cationization does not increase even if more than that is added, and the degree of cationization is low if it is less than 1/50 (mole ratio). However, this does not limit the lower limit. The cationization method of the present invention is particularly suitably applied to cationization of an acrylic acid hydrazide polymer compound () in an aqueous solution state. At this time, as a method for adding heavy metal ions to the acrylic acid hydrazide polymer compound (), the heavy metal ions may be added to an aqueous solution of the polymer compound, or the polymer compound and heavy metal ions may be added together in water. May be added. Furthermore, the polymer compound may be added to an aqueous solution containing heavy metals. The cationization method of the present invention is applicable when the acrylic acid hydrazide polymer compound () is cationized in advance and used as a size fixing agent for paper, a paper strength enhancer, a flocculant, etc., or when it is used in a liquid to be treated. It is applicable to any of the cases where the acrylic acid hydrazide polymer compound () is cationized and used for the above-mentioned purposes. Acrylic acid hydrazide polymer compound () usually has a concentration of 0.5~
Used at a concentration of 5000ppm. As mentioned above, when using the method of the present invention, acrylic acid hydrazide-based polymer compounds can be treated with heavy metal ions even at low concentrations, even in neutral or alkaline aqueous solutions, or even in diluted states. It becomes possible to cationize the polymer compound, which makes it possible to practically utilize the polymer compound as a size fixing agent for paper, a paper strength enhancer, a flocculant, etc., which is extremely advantageous industrially. Next, the method of the present invention will be explained by referring to Reference Examples, Examples, and Comparative Examples. Note that the reference example shows a production example of an acrylic acid hydrazide-based polymer compound. Also, % is weight % unless otherwise specified.
It is. Reference Example 1 1 kg of a 10% aqueous solution of polyacrylamide having an average molecular weight of about 200,000 and 1 kg of an 80% aqueous hydrazine hydrate solution were added to a four-necked flask from Reference Example 1 3, and the mixture was reacted at 55° C. for 3 hours with stirring. The resulting viscous solution was poured into about 15 times the volume of methanol to obtain a white precipitate. This product was purified by reprecipitation method and then heated to 60°C.
It was dried under reduced pressure. The content of acrylic acid hydrazide units in the obtained polymer compound was 30 mol% (according to iodometric titration, hereinafter the same). Reference Example 2 200 g of polymethyl acrylate having an average molecular weight of about 800,000 and 2 kg of an 80% aqueous hydrazine hydrate solution were added to the four-necked flask of Reference Example 2, and the mixture was reacted at 80° C. for 5 hours with stirring. The resulting viscous solution was poured into about 20 methanol to obtain a white precipitate. This product was purified by a reprecipitation method and then dried under reduced pressure at 60°C. The content of acrylic acid hydrazide units in the obtained polymer was 88 mol%. Reference Example 3 1 kg of a 10% aqueous solution of polyacrylamide having an average molecular weight of about 45,000 and 1 kg of an 80% aqueous hydrazine hydrate solution were added to the four-necked flask from Reference Example 3, and the mixture was reacted at 55° C. for 6 hours with stirring. The resulting viscous solution was poured into about 20 times the volume of methanol to obtain a white precipitate. This product was purified by reprecipitation method and then heated to 60°C.
It was dried under reduced pressure. The content of acrylic acid hydrazide units in the obtained polymer was 60 mol%. Reference Example 4 100 g of acrylamide and styrene copolymer containing 10 mol% of styrene units and 1.5 kg of 80% hydrazine hydrate aqueous solution were placed in the four-necked flask from 3.
and heated at 80℃ for 10 minutes while stirring in a nitrogen stream.
The mixture was allowed to react for a period of time, and then treated in the same manner as in Reference Example 1 to obtain a polymer compound. The content of acrylic acid hydrazide units in this product was 82 mol%. Examples 1 to 8 and Comparative Example 1 0.1 g of the acrylic acid hydrazide polymer compound obtained in Reference Example 1 was dissolved in 1 part of distilled water.
A 100 ppm (w/v) solution was prepared. This solution 100
Take ml of ZnCl ₂ , FeCl ₃ −6H ₂ O, CoCl ₂・6H ₂ O,
0.1% of _{Cu2Cl2 ・ 2H2O} , _NiCl2・_6H2O , _HgCl2
After adding (w/v) solutions as shown in Table 1 and stirring for 1 minute, 1/400-N polyvinyl potassium sulfate (PVSK) was added using toluidine blue as an indicator.
Table 1 shows the results of colloid titration with an aqueous solution. For comparison, an experiment similar to the above was conducted without adding heavy metal ions.

[Table] Examples 9 to 11 and Comparative Examples 2 to 4 The acrylic acid hydrazide polymer compounds obtained in Reference Examples 2 to 4 were added to 100 ppm in the same manner as in Examples 1 to 8.
Prepare a solution, take 100 ml of this solution and add 0.1 of ZnCl ₂
After adding 1 ml of % solution and mixing for 1 minute, colloid titration was performed with 1/400-NPVSK in the same manner as in Examples 1-8. For comparison, an experiment similar to the above was conducted without adding ZnCl ₂ . The results are shown in Table 2.

【table】

[Table] Example 12 and Comparative Example 5 0.1 part of ZnCl ₂ was added to 49.9 parts of a solution of 1 part of the acrylic acid hydrazide polymer compound obtained in Reference Example 1 (parts by weight, hereinafter the same) in 49 parts of water. A cationized acrylic acid hydrazide polymer compound solution was prepared by adding and mixing the solution dissolved in water. On the other hand, 100 copies of bone dry pulp (NUKP) were torn by hand.
Place in a TAPPI beater with 9900 parts of water.
Beaten to CSF (Canadian Standard Form Water) 360. The cationized acrylic acid hydrazide polymer compound solution and 0.5 part of a rosin sizing agent were added to the pulp slurry after beating. PH of pulp slurry
was 7. After stirring for 1 minute,
The paper was made on a TAPPI standard paper machine. After drying at 105℃,
It was left standing for 24 hours under conditions of 20°C and 65% RH.
The basis weight of the obtained paper was measured, and the specific bursting strength (JIS P-1112) and specific compressive strength (JIS P
-8126), rupture length (JIS P-8113) and Steckigt size degree (JIS P-8135). For comparison, an experiment similar to the above was conducted using an acrylic acid hydrazide polymer compound to which ZnCl ₂ was not added. The results are shown in Table 3.

[Table] Example 13 Zinc chloride was added to a solution of 1 part of the acrylic acid hydrazide polymer compound obtained in Reference Example 1 in 49 parts of water.
Prepare a cationized acrylic acid hydrazide polymer compound solution by adding and mixing 0.1 part dissolved in 49.9 parts of water, take 1 part of it, suspend 50 parts of kaolin in 9950 parts of water, and add and mix it. - When added to a suspension made to pH 11 with KOH and stirred gently, a very large floc was obtained. Comparative Example 6 1 part of the acrylic acid hydrazide polymer compound obtained in Reference Example 1 was dissolved in 99 parts of water, 1 part was taken, 50 parts of kaolin was suspended in 9950 parts of water, and IN
When added to a suspension adjusted to pH 11 with -KOH and gently stirred, no floc formation was observed. The results are shown in Table 4.

【table】

Claims (1)

[Claims] 1 General formula (): (In the formula, X is a hydrogen atom or a methyl group, and A
is an acrylamide, methacrylamide, acrylic ester or methacrylic ester unit, B is a monomer unit copolymerizable with acrylamide, methacrylamide, acrylic ester or methacrylic ester, l, m and n are 0 mol% 1. A method for cationizing an acrylic acid hydrazide polymer compound, the method comprising causing a heavy metal ion to act on the acrylic acid hydrazide polymer compound having the following relationship: <l≦91 mol% l+m+n=100 mol%.