JPH0480925B2 - - 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 polymers have been used as polymer flocculants, paper-strengthening agents, paper-making agents, warp sizing agents,
It is attracting attention as a raw material base for antistatic agents, fiber dyeability improvers, antibacterial agents, antifungal agents, and 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, 1795 (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) the copolymerization rate of vinylpyridine and vinyl acetate is extremely slow; Since alkyl (meth)acrylamide has an amide group, even if a cationic monomer can be introduced into the polymer, the cationic group disappears or decreases during the saponification process or aqueous solution (3) Aminoalkyl (meth) Judging from the reactivity ratio of the monomers in the copolymer of acrylamide and vinyl acetate, it is very easy to form a homopolymer of aminoalkyl (meth)acrylamide. It is expected that the proportion of cationic monomers contained in the copolymer with the cationic monomer 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 develop a method for producing a cationic copolymer that stably retains cationic groups. It is about providing. [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], R ₁ and R ₂ are the same or different lower alkyl groups,
X means an anion. ] A monomer represented by the following general formula (): CH ₂ = CH-O-CO-R ₃
... () (in the formula, R ₃ represents hydrogen or a lower alkyl group) A step of copolymerizing with a vinyl ester represented by This is a method for producing a cationic copolymer, which includes the steps of quaternizing the polymer by adding an acid to the aqueous solution or adding an alkylating quaternizing agent. 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-( Salts of suitable acids such as 3-allyloxy-2-hydroxy-2-methylpropyl)diethylamine, N-(4-allyloxy-3-hydroxybutyl)diethylamine, monomers such as hydrochlorides, acetates, sulfates, etc. can be given. Examples of the vinyl ester represented by the above formula include vinyl formate, vinyl acetate, and vinyl propionate, with vinyl acetate being particularly preferred. Regarding the copolymerization method, any polymerization method such as solution polymerization or emulsion polymerization is possible, but 2,2'-azobisisobutyronitrile or 2,2'-azobisisobutyronitrile or Methanol solution polymerization using benzoyl peroxide etc. is easy to put into practical use. Although it is often desirable for the amino group to be in the form of a quaternary ammonium salt from the viewpoint of exhibiting cationic properties, it is preferable that the amino group be in the form of a quaternary ammonium salt, but it is _preferable that the amino group be in the form of a _quaternary ammonium salt.
In some cases, the shape of is important. When a quaternary amine monomer is used as a suitable acid salt, such as hydrochloride, acetate, or sulfate, during polymerization, the cationic copolymer salt is formed during the saponification step after copolymerization. Returning to the tertiary amine due to the alkali, the cationic copolymer of the tertiary amino group type is made into an aqueous solution and the appropriate acid mentioned above is added to carry out the quaternization reaction, or an alkyl halide, dialkyl sulfate and The quaternization reaction can also be carried out using a lower alkylating agent such as alkyl p-toluenesulfonate. In the case of alkyl quaternization reactions, the most suitable alkylating agent in terms of cost and process control is methyl chloride, and almost 100% alkyl quaternization can be achieved by simply bubbling methyl chloride gas into an aqueous solution of the copolymer. It is possible. The polymerization temperature may be 50°C to the boiling point of the polymerization reaction system, and there are no particular restrictions on the degree of polymerization and the amount of cationic groups, but the degree of polymerization is 300 to 3000, and the content of cationic groups is
Desirably 0.01 to 20 mol%. Although the unreacted vinyl ester monomer represented by the formula can be removed by distillation or the like, the cationic monomer represented by the formula may remain, especially during the saponification step. The step of saponifying 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, this is a saponification method using an alkali catalyst in an alcohol solution. Examples of alkaline catalysts include sodium and potassium hydroxides or alcoholates, but economically, in methanol solution,
A method using a sodium hydroxide catalyst is preferred.
Moreover, before saponification, the solution of the copolymer may be neutralized and then saponified. 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 it is within the range of 65 to 100 that can be produced industrially advantageously.
selected from mol%. Examples of anions represented by X in the copolymer include Cl, Br, _CH3COO , _SO42 ^,
There are _CH3OS3 , _CH3 - _{C6H4 - SO3,} etc., but Cl is preferable from the _viewpoint of cost and safety. As explained above, since the cationic structural unit of the cationic copolymer of the present invention has a stable ether bond, the cationic group is retained sufficiently stably even after the saponification process in an aqueous solution. It has the characteristics and advantages of The cationized PVA according to the present invention is a polymer flocculant,
Paper manufacturing agents that increase paper strength, improve sizing, and improve yield, sizing agents for warp sizing, fiber dyeability improvers,
It can be used in antistatic agents, ion exchange resins, emulsion polymerization emulsion stabilizers, rust preventives, antifungal agents, binders for glass fibers, adhesives, and the like. [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. The attached drawings are proton nuclear magnetic resonance spectra of the target copolymers 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 measured at 20℃ using a B-type viscometer.
This is the Bruckfield viscosity value of a 4% aqueous solution in , which corresponds to the degree of polymerization. Example 1 2700 parts of vinyl acetate was placed in a 5-separable flask equipped with a stirrer, a thermometer, a dropping funnel, and a reflux condenser.
300 parts of methanol and 1.5 parts of 2-2'-azobisisobutyronitrile were charged, and after deoxidizing by bubbling nitrogen gas for 30 minutes, N-(3-allyloxy-2-
Hydroxypropyl) dimethylamine acetate 135
The copolymerization was carried out at 60° C. for 6 hours while dropping a portion of the mixture dropwise.
The solid content concentration of the copolymer was 51.4% 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 200 parts of a 2.4N methanol solution of sodium hydroxide was added to 3,400 parts of this methanol solution and mixed, the system became viscous and particles precipitated after 31 minutes. After washing with methanol, it was dried to obtain a white copolymer. The degree of saponification of vinyl acetate alone was 99.6 mol%. The viscosity of this copolymer was 45.3 cps. The first proton nuclear magnetic resonance spectrum of this copolymer was
As shown in the figure. The absorption at 2.65 ppm is attributed to the two methyl groups bonded to the nitrogen atom of the N-(3-allyloxy-2-hydroxypropyl) dimethylamine structural unit, and its strength indicates that it is N-(3-allyloxy-2-hydroxypropyl). It was found that 2.3 mol% of dimethylamine units were contained. Example 2 The copolymer obtained in Example 1 was made into a 10% aqueous solution, and 1
% acetic acid aqueous solution to adjust the pH to 7.5~7 and
(3-allyloxy-2-hydroxypropyl)
A cationic copolymer containing a dimethylamine acetate structural unit was obtained. Example 3 A 10% aqueous solution of the copolymer obtained in Example 1 was charged into a reaction vessel equipped with a stirrer, a gas introduction pipe, and a reflux condenser, and stirred at 40°C for 2 hours while bubbling methyl chloride gas. I let it happen. The nuclear magnetic resonance spectrum of this copolymer is shown in FIG. Figure 2 shows that the amino group of the N-(3-allyloxy-2-hydroxypropyl)dimethylamine structural unit is completely quaternized and N-(3-allyloxy-2-hydroxypropyl).
hydroxypropyl) trimethylammonium chloride unit, and it was confirmed from the intensity of 3.22 ppm that the unit was contained in an amount of 2.3 mol%. Example 4 In the same manner as in Example 1, vinyl acetate and N-(3-allyloxy-2-hydroxy-2-methylpropyl)dimethylamine hydrochloride were copolymerized for 7 hours. The solid content concentration of the copolymer was 57.6% by weight. 188 parts of a methanol solution of 2.4N sodium hydroxide was added to 4,500 parts of a methanol solution of the copolymer prepared at 30°C to a concentration of 30%, and the mixture was saponified. After 35 minutes, the system became viscous and white particles were formed. It precipitated. N-(3
-Allyloxy-2-hydroxy-2-methylpropyl)dimethylamine structural unit content is 1.1
It was in mol%. The degree of saponification is 98.9 mol%,
The viscosity was 58.5 cps. Example 5 The copolymer obtained in Example 4 was made into a 10% aqueous solution, and 1
% hydrochloric acid aqueous solution to adjust the pH to 7.5~7, and
A cationic copolymer containing a (3-allyloxy-2-hydroxy-2-methylpropyl) dimethylamine hydrochloride structural unit was obtained. Example 6 Vinyl acetate and N-(4-
Allyloxy-3-hydroxybutyl) dimethylamine acetate was copolymerized for 4 hours. The solid content concentration of the copolymer was 39.7% by weight. of the copolymer
Prepare a 30% methanol solution at 30℃, and add 2.4N methanol solution of sodium hydroxide to 1070 parts of this.
When 129 parts were added, mixed and saponified, the system became viscous after 40 minutes and white particles were precipitated. Furthermore, 65 parts of a 2.4N methanol solution of sodium hydroxide was added,
They were mixed and subjected to secondary saponification. N-(4-allyloxy-3-
The content of the (hydroxybutyl)dimethylamine structural unit was 0.76 mol%. The degree of saponification was 100 mol%, and the viscosity was 32.0 cps. Example 7 A 10% aqueous solution of the copolymer obtained in Example 6 was charged into a reaction vessel equipped with a stirrer, a gas inlet tube, and a reflux condenser tube, and stirred at 40°C for 2 hours while bubbling methyl chloride gas. I let it happen. The proton nuclear magnetic resonance spectrum of this copolymer revealed that the amino groups in the N-(4-allyloxy-3-hydroxybutyl)dimethylamine structural unit were completely quaternized and became N-(4-allyloxy-3-hydroxybutyl). )
It is a trimethylammonium chloride unit, and from its intensity of 3.22 ppm, the unit is 0.76 mol%.
It was confirmed that it was contained. Comparative Example 1 Vinyl acetate 2500 was added to a 5-separable flask equipped with a stirrer, thermometer, dropping funnel, and reflux condenser.
1 part, 375 parts of methanol, and 3 parts of N-(3-dimethylaminopropyl)acrylamide, and after deoxidizing by bubbling nitrogen gas for 30 minutes, the internal temperature was raised to 60°C.
And so. To this system, 0.6 part of 2,2'-azobisisobutyronitrile was added together with 250 parts of methanol to initiate polymerization. During the polymerization time of 2 hours and 20 minutes, N-
Fifty parts of a 10% by weight methanol solution of (3-dimethylaminopropyl)acrylamide was added dropwise at a constant rate to the stirring polymerization system. The solid content concentration of the polymerization system at the time of termination of polymerization was 11.4% by weight. From the obtained polymer solution, unreacted vinyl acetate was removed in the same manner as in Example 1 to prepare a 30% by weight copolymer methanol solution. The content of N-(3-dimethylaminopropyl)acrylamide units in this copolymer determined from proton nuclear magnetic resonance spectrum was 1.1 mol%. 1200 parts of a methanol solution of this copolymer at 30°C
When 145 parts of a 2.4N methanol solution of sodium hydroxide was added and mixed, the system became viscous and white particles precipitated after 35 minutes. Then, the temperature of the system was set to 50℃, and a 2.4N methanol solution of sodium hydroxide was added.
75 parts were added and mixed for further saponification. The degree of saponification of this copolymer was 100 mol%, and the content of N-(3-dimethylaminopropyl)acrylamide units determined from proton nuclear magnetic resonance spectrum was 0.1 mol%. Each of the cationic copolymers and completely saponified unmodified PVA (K-17 manufactured by Denki Kagaku Kogyo, hereinafter referred to as Comparative Example 2) obtained in Examples 1 to 7 and Comparative Example 1 was made into paper by the following method. An evaluation test was conducted as an internal additive. The copolymer obtained in each example and comparative example or the unmodified PVA mentioned above was added to a 3% by weight slurry dispersion of L-BKP/N-BKP = 80/20 in 400 ml of Canadian Standard Freeness as a pulp solid content. Calcium carbonate (NITOREX #70 manufactured by Nippon Funka Kogyo) was added at 20% by weight based on the pulp solid content, and water was added to dilute to 0.6% by weight. Furthermore, an alkyl ketene dimer-based sizing agent (Harcon W manufactured by Deitsku Hercules) and a fixing agent (cationic resin Hireten 101 manufactured by Deitsku Hercules) were added to the pulp solid content, respectively.
Add 0.2 wt% and 0.02 wt%, add water to 0.2
% by weight. This paper making stock solution is processed into JIS P
Paper was made based on the paper making method of No. 8209 to have a basis weight of 60±5 g/m ² . The paper was pressed for 5 minutes at a pressure of 3.5Kg/ ^m2 , then dried in a drum dryer at 105℃ for 5 minutes, and then conditioned for 48 hours in an atmosphere of 20℃ and 65%RH, and the properties of the paper were measured. did. In addition, each copolymer and
The content ratio of each PVA was measured by the iodine coloring method, and the value was converted to determine the fixation rate to the pulp. Further, the properties of the above-mentioned humidity-conditioned paper were measured by the following method. The results of these measurements are shown in Table 1.・Rupture length: JIS P 8113 (using Tensilon tensile testing machine) ・Tearing strength: JIS P 8112 ・Stekihyde sizing degree: JIS P 8122 ・Calcium carbonate yield: Based on scorching ash content [Table]

[Brief explanation of the drawing]

1 and 2 are proton nuclear magnetic resonance spectra of the cationic copolymers of the present invention shown in Examples 1 and 3.

Claims (1)

[Claims] 1. The following general formula (): [In the formula, A represents [Formula] [Formula] or [Formula], R ₁ and R ₂ are the same or different lower alkyl groups,
X means an anion. ] A monomer represented by the following general formula (): CH ₂ = CH-O-CO-R ₃
...() A step of copolymerizing with a vinyl ester represented by (in the formula, R ₃ represents hydrogen or a lower alkyl group),
Partially or completely saponifying the resulting copolymer and preparing the cationic copolymer as an aqueous solution by adding an acid or adding an alkylating quaternizing agent to a fourth stage.
1. A method for producing a cationic copolymer, comprising the steps of grading. 2. The method for producing a cationic copolymer according to claim 1, wherein the vinyl ester represented by the general formula () is vinyl acetate.