JPH0328442B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to polyvinyl alcohol (hereinafter referred to as
This invention relates to a method for producing a cationic copolymer in which a cationic group is introduced into the chain (abbreviated as PVA). [Prior art] In recent years, cationic copolymers have been used as polymer flocculants, paper-making agents such as paper strength enhancers, warp sizing pastes, antistatic agents, fiber dyeability improvers, antibacterial agents, and antifungal agents. , is attracting attention as a raw material base for ion exchange resins. PVA has been used for a long time to improve the strength of paper for surface sizing and fiber warp sizing, but recently, PVA has been used as an internal additive to improve paper strength, size properties, water resistance, and fiber yield. It suddenly increased. Despite these expectations, cationized polyvinyl alcohol has not yet been put into practical use because it is difficult to introduce cationic groups into PVA. The following methods have been disclosed as conventional methods for introducing cationic groups into PVA. A. Method for post-modifying polymers (a) Japanese Patent Publication No. 30-5563, Collection of Polymers,
34, 843 (1977), the introduction of amino groups by aminoacetalization of PVA. (b) Japanese Patent Publication No. 57-34842 discloses a method for producing cationic PVA containing a quaternary ammonium salt by reacting glycidyltrimethylammonium chloride with PVA in the presence of an alkali catalyst. Similarly, 3-chloro-2-hydroxypropyltrimethylammonium chloride with a glycidyl group opened
There are also reports of reactions with PVA. (c) Journal of the Chemical Society of Japan, 1975 (11) P.1955-2000
Now let's react PVA with epichlorohydrin,
Furthermore, cationized PVA is obtained by reacting polyethylene polyamine. B. Copolymerization method (a) In the method reported in Kobunshi Kagaku, 8 , 467 (1951), PVA is obtained by saponifying a copolymer of vinyl acetate and vinylpyridine. (b) JP-A-56-14504, JP-A-56-88413,
JP-A-56-118997 discloses a method for obtaining cationized PVA by saponifying a copolymer of aminoalkyl (meth)acrylamide, aminoalkyl (meth)acrylate (or its quaternary ammonium salt), and vinyl acetate. is disclosed. However, although the production method of introducing a cationic group by post-modification in Method A is possible in small-scale experiments, various problems listed below arise when attempting to produce it industrially. (1) In order to conduct the reaction uniformly, a PVA dissolution step is required. (2) It is generally difficult to produce products with a certain degree of modification. (3) Often involves cross-linking reactions, and polymer compounds tend to gel. On the other hand, Method B, which uses copolymerization, overcomes the above drawbacks and can be fully industrialized in terms of cost, but (1) the copolymerization rate of vinylpyridine and vinyl acetate is extremely slow (2) aminoalkyl (Meth)acrylamide has an amide group, so even if a cationic monomer can be introduced into the polymer, the cationic group will disappear or decrease during the saponification process or aqueous solution (3) Aminoalkyl (meth)acrylamide Judging from the reactivity ratio of the monomers, a homopolymer of aminoalkyl (meth)acrylamide is very easy to form in the copolymer of vinyl acetate and vinyl acetate compared to the monomers charged. It is expected that the proportion of cationic monomers contained in the copolymer is very low, and it can be said that it is unsuitable for industrial use. In addition, aminoalkyl (meth)acrylates and their quaternary ammonium salts are also produced industrially as cationic monomers, but these monomers cannot be copolymerized with vinyl esters, especially vinyl acetate. However, in the process of saponifying the copolymer, the ester bonds of the cationic monomers are also saponified at the same time, making it impossible to introduce cationic groups into PVA. In summary, in the prior art, due to the low reactivity of the cationizing agent or the difficulty in producing a uniform degree of modification, and even if a cationic group could be introduced, the cationic structure At present, it has not been commercialized due to partial or complete elimination of the cationic group due to instability of the unit. [Object of the Invention] The present invention was made as a result of repeated research to compensate for the drawbacks of the prior art described above, and its purpose is to provide a cationic copolymer that stably retains cationic groups and a method for producing the same. Our goal is to provide the following. [Structure of the Invention] To summarize the present invention, the present invention relates to a method for producing a cationic copolymer, which has the following general formula: [In the formula, A represents [Formula] [Formula] or [Formula], B represents [Formula] and/or [Formula] (However, R ₁ is the same or different lower alkyl group,
means an anion)], and the following general formula: In a method for producing a cationic copolymer containing a copolymer unit represented by the following general formula: (In the formula, A and B are synonymous with the above formula) and the following general formula: CH ₂ = CH-O-CO-R ₂ ...... () (In the formula, R ₂ is hydrogen or a step of copolymerizing with a vinyl ester represented by (representing a lower alkyl group),
and a step of partially or completely saponifying the resulting copolymer. The cationic copolymer of the present invention has the following general formula: (In the formula, R ₂ represents hydrogen or a lower alkyl group.) It may include a copolymerized unit represented by the formula: When partially saponified, a cationic copolymer containing copolymerized units represented by the above formula can be obtained. Further, in the above invention, when at least a part of the group B in the target cationic copolymer is a quaternary ammonium group, a material containing the corresponding group B may be used as the raw material. However, as an alternative method, when at least a part of the groups B of the raw materials and/or intermediates are tertiary amino groups and the amount of quaternary ammonium groups is smaller than that in the target compound, the above-mentioned saponification The desired copolymer may be obtained by performing quaternization using a quaternizing agent before or after the step. Examples of the cationic monomers represented by the above formula used in the present invention include N-(3-allyloxy-2-hydroxypropyl)dimethylamine, N
-(3-allyloxy-2-hydroxy-2-methylpropyl)dimethylamine, N-(4-allyloxy-3-hydroxybutyl)dimethylamine, N-(3-allyloxy-2-hydroxypropyl)diethylamine, N-( 3-allyloxy-2-hydroxy-2-methylpropyl)diethylamine, N-(4-allyloxy-3-hydroxybutyl)diethylamine and their quaternary
There are monomers of class ammonium salts. Any copolymerization method such as solution polymerization or emulsion polymerization is possible, but 2,2'-azobisisobutyronitrile is currently used as a radical polymerization initiator in the industrial production of PVA. Alternatively, methanol solution polymerization using benzoyl peroxide or the like is easy to put into practical use. The polymerization temperature at that time may be 50°C to the boiling point of the polymerization reaction system, and there are no particular restrictions on the degree of polymerization or the amount of cationic groups, but the degree of polymerization is 300°C to the boiling point of the polymerization reaction system.
2000, a cationic group content of 0.01 to 20 mol% is desirable. Note that the degree of polymerization was measured according to JIS K6726. The unreacted vinyl ester monomer represented by the formula can be removed by distillation etc.
The cationic monomer represented by the formula may remain, especially during the saponification step. The saponification step of the obtained copolymer may be carried out by a conventional method, and it is particularly preferable to use the method currently used in the industrial production of PVA as it is. That is, it is a saponification method using an alkali catalyst in an alcohol solution. Examples of alkali catalysts include sodium or potassium hydroxides and alcoholates, but from an economic standpoint, it is desirable to use a sodium hydroxide catalyst in a methanol solution. The amount of the alkali catalyst is preferably 0.001 to 0.1 molar equivalent relative to the vinyl ester unit. The degree of saponification may be varied depending on the purpose, but a range of 65 to 100 mol % is selected as a range that can be industrially advantageously produced. Quaternization, which may be carried out as necessary before or after this saponification step, can be carried out according to a conventional method. However, when quaternization is performed after copolymerization and before the saponification step, lower alkylating agents such as alkyl halides, dialkyl sulfates, and alkyl p-toluenesulfonates are used in alcoholic solutions, especially methanol solutions. It is desirable to quaternize the material. In this case, the most suitable alkylating agent in terms of cost and process control is methyl chloride, and almost 100% quaternization can be achieved simply by bubbling methyl chloride gas into an alcoholic solution of the copolymer. In addition, when quaternization is performed after the saponification step, it is desirable to use a lower alkylating agent, particularly methyl chloride gas, in an aqueous solution. Examples of anions represented by X in the copolymer include Cl, Br, _CH3COO , _{CH3OSO3 ,}
There are _CH3 - _{C6H4 - SO3} , etc., but Cl is preferable from the viewpoint of cost and safety. As explained above, the cationic copolymer of the present invention has a stable ether bond in the cationic structural unit, so that the cationic group is retained sufficiently stably even after the saponification process in an aqueous solution. It has the characteristics and advantages of being The cationized PVA according to the present invention can be used as a polymer flocculant, a papermaking agent for increasing paper strength, improving sizing properties, improving yield, etc., a sizing agent for warp sizing, a fiber dyeability improver, an antistatic agent, an ion exchange resin, It can be used in emulsion polymerization emulsion stabilizers, rust preventives, antifungal agents, binders for glass fibers, adhesives, etc. [Examples of the Invention] Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited to these Examples. In the examples, "part" means part by weight. In addition,
The attached drawing is a proton nuclear magnetic resonance spectrum diagram of the target copolymer in Examples. The solvent in this measurement is D ₂ O, and the reference substance is trimethylsilylpropionic acid- _{d 4} -sodium salt. In addition, the viscosity in each example was determined using a B-type viscometer.
℃, Bruckfield viscosity value of a 4% aqueous solution, which corresponds to the degree of polymerization. Example 1 Vinyl acetate 800 was added to a three-separable flask equipped with a stirrer, thermometer, addition funnel, and reflux condenser.
1 part, 200 parts of methanol, 2 parts of 2,2'-azobisisobutyronitrile, and after deoxidizing by bubbling nitrogen gas for 30 minutes, add N-(3
-Allyloxy-2-hydroxypropyl)trimethylammonium chloride dissolved in vinyl acetate at 5% by weight was added dropwise to
Polymerization was carried out at ℃ for 5 hours. The solid content concentration of the copolymer is
It was 46.3% by weight. After removing unreacted vinyl acetate by blowing methanol vapor into the polymerization reaction solution, the copolymer was heated at 30℃ for 30 minutes.
% methanol solution was prepared. When 67 parts of a 2.5N methanol solution of sodium hydroxide was added to 1200 parts of this methanol solution and mixed, the system became viscous after 8 minutes and particles precipitated. After washing with methanol, it was dried to obtain a white copolymer. The degree of saponification of vinyl acetate units was 97.7 mol%. The viscosity of this copolymer was 31.2 cps. The proton nuclear magnetic resonance spectrum of this copolymer is shown in FIG. The absorption at 3.22 ppm is N-(3-
It is attributed to the three methyl groups bonded to the ammonium nitrogen of allyloxy-2-hydroxypropyl)trimethylammonium chloride, and based on its strength, the N-(3-allyloxy-2-hydroxypropyl)trimethylammonium chloride unit is contained at 0.71 mol%. It turned out that Example 2 As in Example 1, vinyl acetate and N-(3-allyloxy-2-hydroxypropyl)dimethylamine were copolymerized for 7.5 hours. The solids concentration of the copolymer was 33.5% by weight. After removing the monomer, a 30% methanol solution of the copolymer was prepared at 30°C, and 22 parts of a 2.5N methanol solution of sodium hydroxide was added to 400 parts of this methanol solution, and the mixture was saponified. However, after 12 minutes, the system became viscous.
White particles precipitated. In the same manner as in Example 1,
The copolymer was isolated. This saponification degree is 95.6 mol%
It was hot. The viscosity of this copolymer was 38.5 cps. The proton nuclear magnetic resonance spectrum of this copolymer is shown in FIG. The absorption of 2.65 ppm is N-(3
-allyloxy-2-hydroxypropyl)dimethylamine, and it was found that 1.9 mol% of the monomer units were copolymerized. Example 3 N-(3-allyloxy-2- obtained in Example 2)
400 parts of a 30% methanol solution of (hydroxypropyl) dimethylamine-vinyl acetate copolymer was placed in a reaction vessel equipped with a stirrer, a gas inlet tube, and a reflux condenser tube, and the mixture was stirred at 40°C for 2 hours while bubbling methyl chloride gas. Ta. Next, while adjusting the liquid temperature to 30°C, 22 parts of a 2.5N methanol solution of sodium hydroxide was added, mixed, and saponified. After 12 minutes, the system became viscous and fine particles were precipitated.
FIG. 3 shows the nuclear magnetic resonance spectrum of the saponified copolymer isolated in the same manner as in the previous example. From this Figure 3, the amino group of N-(3-allyloxy-2-hydroxypropyl)dimethylamine is completely quaternized and becomes an N-(3-allyloxy-2-hydroxypropyl)trimethylammonium chloride unit. From the absorption intensity of 3.22 ppm, it was confirmed that the unit was contained in an amount of 1.9 mol%. The degree of saponification was 97.3 mol%. The viscosity of this copolymer was 35.5 cps. Example 4 In the same manner as in Example 1, vinyl acetate and N-(3-allyloxy-2-hydroxy-2-methylpropyl)trimethylammonium chloride were copolymerized for 5 hours. The solids concentration of the copolymer was 42.5% by weight. 44 parts of a methanol solution of 2.5N sodium hydroxide was added to 1000 parts of a methanol solution of the copolymer prepared to a concentration of 30% at 30°C, and the mixture was saponified. After 15 minutes, the system became viscous and white particles were formed. was precipitated. N determined from the proton nuclear magnetic resonance spectrum of this copolymer isolated in the same manner as in the previous example.
The content of -(3-allyloxy-2-hydroxy-2-methylpropyl)trimethylammonium chloride units was 2.9 mol%. The degree of saponification was 98.7 mol%. The viscosity of this copolymer was 28.8 cps. Example 5 In the same manner as in Example 1, vinyl acetate and N-(4-allyloxy-3-hydroxybutyl)trimethylammonium chloride were polymerized for 8 hours. The solid content concentration of the copolymer was 46.2% by weight. 30℃,
Methanol solution of the copolymer adjusted to a concentration of 30%
44 parts of a 2.5N methanol solution of sodium hydroxide was added to 1200 parts, mixed, and saponified. After 14 minutes, the system became viscous and white particles were precipitated. The content of N-(4-allyloxy-3-hydroxybutyl)trimethylammonium chloride units determined from proton nuclear magnetic resonance spectrum of this copolymer isolated in the same manner as in the previous example was 2.4 mol%. The degree of saponification was 96.2%. The viscosity of this copolymer was 41.3 cps. Example 6 In the same manner as in Example 1, vinyl acetate and N-(3
-allyloxy-2-hydroxypropyl)trimethylammonium chloride for 4 hours. The solid content concentration of the copolymer was 42.4% by weight. Prepare a 30% methanol solution of the copolymer at 30°C, add 18 parts of 2.5N methanol solution of sodium hydroxide to 1000 parts of this, mix and saponify; the system becomes viscous and white after 20 minutes. Particles were precipitated. Further, 20 parts of a 2.5N methanol solution of sodium hydroxide was added and mixed to perform secondary saponification. The N-
(3-allyloxy-2-hydroxypropyl)
The content of trimethylammonium chloride units was 0.47 mol%. Saponification degree is 100 mol%
It was hot. The viscosity of this copolymer was 34.6 cps. [Effects of the Invention] As explained in detail above, the cationic copolymer of the present invention is superior to conventional cationized PVA in that it stably retains and contains cationic groups, and thereby , which is excellent in that new uses can be developed.

[Brief explanation of drawings]

1 to 3 are proton nuclear magnetic resonance spectra of the cationic copolymers of the present invention shown in Examples 1 to 3.

Claims (1)

[Claims] 1. The following general formula: [In the formula, A represents [Formula] [Formula] or [Formula], B represents [Formula] and/or [Formula] (wherein R ₁ is the same or different and represents a lower alkyl group, and X represents an anion) ] The copolymerized unit represented by and the following general formula: In the method for producing a cationic copolymer containing a copolymer unit represented by the following general formula: (In the formula, A and B are synonymous with the above formula) and the following general formula V: CH ₂ = CH-O-CO-R ₂ ...... () (In the formula, R ₂ is a step of copolymerizing a vinyl ester represented by hydrogen or a lower alkyl group;
and a step of partially or completely saponifying the resulting copolymer. 2 The cationic copolymer has the following general formula: 2. The method for producing a cationic copolymer according to claim 1, which includes a copolymer unit represented by the following formula (wherein R ₂ represents hydrogen or a lower alkyl group). 3 At least a part of the groups B in the cationic copolymer are quaternary ammonium groups, and the raw material and/or
Or, if at least a part of the groups B in the intermediate is a tertiary amino group and the amount of quaternary ammonium groups is less than that in the target compound, quaternary 2. A method for producing a cationic copolymer according to claim 1 or 2, wherein quaternization is carried out using a curing agent. 4. The method for producing a cationic copolymer according to any one of claims 1 to 3, wherein the vinyl ester represented by the general formula is vinyl acetate.