JPH0144723B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a novel cationic polymer emulsion with excellent performance, stability, and economy, and more specifically, the present invention relates to a method for producing a novel cationic polymer emulsion having excellent performance, stability, and economy. The present invention relates to a method for producing a cationic emulsion characterized by emulsion polymerization of ethylenically unsaturated monomers in the presence of polyvinyl alcohol (abbreviated as PVA). (Here, A is

[expression] or

[Formula] R ² and R ³ are lower alkyl groups which may contain a substituent, and X each represents a negative group that forms a salt with ammonium nitrogen. ) Conventionally, emulsion stabilizers used in the production of vinyl polymer emulsions include surfactants such as nonionic emulsifiers or anionic emulsifiers, or
It has been common to use water-soluble polymers such as PVA and hydroxyethyl cellulose alone or in combination with each other. The emulsion particles thus produced are necessarily electrically approximately neutral or negatively charged. On the other hand, emulsions made of positively charged particles, that is, cationic emulsions, are also known, and although they have been confirmed to have significant characteristics such as outstanding fixing and adhesive properties, they have traditionally been used in special fields. It was just sitting there. This is thought to be due to the fact that there is still no known effective method for producing cationic emulsions that are satisfactory in terms of stability, performance, or toxicity. It has been known that cationic emulsions can be obtained by emulsion polymerization using cationic surfactants as emulsifiers, and laurylamine salts,
Cationic chloroprene latexes are manufactured using octadecylamine salts, laurylpyridinium chloride, octylbenzyltrimethylammonium chloride, or the like as emulsifiers. In addition, after producing a vinyl polymer emulsion using a nonionic emulsifier or anionic emulsifier, the above-mentioned cationic surfactant or cationic surfactant such as alkylamine or polyoxyethylene is added and mixed, and the PH
Techniques for controlling emulsion particles to cationize them are also known. However, the scope of application of cationic surfactants is currently limited due to toxicity. Also, 2-azobis-
A method of cationizing emulsion particles using a cationic polymerization initiator such as (2-methylpropamidinium) dihydrochloride or 2-azobis-(2'-isopropylimidazolinium) dihydrochloride is also known. However, this method generally yields only products with low cationic performance. Also, so-called "emulsifier-free emulsion polymerization" in which a monomer containing a quaternary cation group and other monomers are copolymerized at the initial stage of polymerization, and then emulsion polymerization is carried out using the resulting copolymer as a protective colloid. has also been proposed, but the control of the process is complicated and it is difficult to produce a stable emulsion. It has also been proposed to produce a cationic emulsion by emulsion polymerization using cationic starch, cationic cellulose, or cationic polyamide polyamine epichlorohydrin as a protective colloid, but these water-soluble polymers has low emulsion stability and lacks emulsion stability when used alone, so nonionic surfactants are generally used in combination.
The balance between cationic performance and emulsion stability remains problematic. PVA has traditionally been known as a water-soluble polymer with excellent protective colloidal action, and has been used in emulsion polymerization of many ethylenically unsaturated monomers, but in particular PVA is a water-soluble polymer with excellent protective colloidal action. In emulsions or copolymer emulsions of vinyl acetate and ethylene, acrylic acid esters, maleic acid diesters, or vinyl versatate, PVA exhibits particularly excellent emulsion stabilizing effects and can be stabilized without the concomitant use of emulsifiers such as surfactants. It is possible to produce emulsion. As described above, PVA is well-known as an excellent emulsion stabilizer, but the concept of using cation-modified PVA as an emulsion stabilizer was completely unknown. This is because the cationic group is
Several methods have been proposed for attaching PVA to PVA, but in all of them, the modification method is expensive and industrial production is difficult.In addition, many of the conventionally proposed methods involve adding PVA to PVA under strong alkaline or acidic conditions.
This is thought to be due to the fact that it is practically impossible to obtain a partially saponified product of modified PVA containing vinyl acetate units, that is, a partially saponified product of modified PVA. This is because, in general, completely saponified PVA has a small emulsion stabilizing effect, while partially saponified PVA having an appropriate degree of saponification and distribution of acetate groups has an excellent emulsion stabilizing effect. The present inventors focused on the industrial usefulness of cationically modified PVA with excellent emulsion stability performance and cationic emulsion produced using it as an emulsifier, studied its industrial production, and published the method in the patent application. Specification No. 124865 (1982)
47402 (see Publication No. 47402), but as a result of further investigation into an industrially advantageous method, the following formula () (Here, A is

[expression] or

[Formula] R ¹ , R ² and R ³ each represent a lower alkyl group (which may contain a substituent), and X represents a negative group that forms a salt with ammonium nitrogen. ) Cationic modified PVA containing as a copolymerized unit
has excellent emulsion stability, and emulsions obtained by emulsion polymerization of various ethylenically unsaturated monomers using this as an emulsion stabilizer are stable and have high cationic properties, making them highly useful in applications such as paper manufacturing, civil engineering, and architecture. The present invention was completed by confirming that the present invention has the following properties. The modified PVA used in the method for producing the cationic polymer emulsion of the present invention is a vinyl ester, especially vinyl acetate, and the following formula (a): (Here, A is

[expression] or

[Formula] R ¹ , R ² and R ³ each represent a lower alkyl group (which may contain a substituent), and X represents a negative group that forms a salt with ammonium nitrogen. ) is copolymerized with the polymerizable monomer represented by A in the presence of a radical polymerization initiator, and then A is copolymerized with

In the case of [Formula], the vinyl ester units in the copolymer are partially converted depending on the purpose by applying an alkali or acid catalyst to an alcohol solution of the copolymer with or without quaternizing with a quaternizing agent. saponified to a vinyl alcohol unit, or A is

[Formula] When the above-mentioned quaternization reaction is not carried out, it can be effectively and easily produced with or without quaternizing with a quaternizing agent after the saponification reaction. Representative examples of the monomer represented by the above general formula (A) include the following. N-(3-dimethylaminopropyl)methacrylamide Trimethyl-3-(1-methacrylamidopropyl)ammonium chloride The amount of copolymerized units containing a cationic group in the cationically modified PVA used as an emulsion stabilizer in the emulsion producing method of the present invention, the degree of saponification of the vinyl ester unit, or the degree of polymerization of the modified PVA are adjusted depending on the purpose. Although there are no particular restrictions on the selection, an appropriate combination of these three elements is important in producing a highly stable emulsion. For most purposes, the amount of cationic groups will be chosen from 0.01 to 10 mol%, the degree of saponification from 60 to 100 mol%, and the degree of polymerization from 300 to 3000. Generally, moderately saponified products have better emulsion stability than completely saponified products, and have the great advantage that they do not require the use of surfactants during polymerization of vinyl acetate emulsions and the like. Also,
Modification for purposes such as obtaining high viscosity emulsions
A partially saponified product produced by employing a saponification method in which the acetate groups in PVA are arranged in blocks along the molecular chain may also be used. Completely saponified products or highly saponified products generally have poor emulsion stability, so when using them in emulsion polymerization, partially saponified cation-modified PVA or partially saponified ordinary PVA should be used together, or surfactants should be used. You may also adopt a method that uses both. The amount of the above-mentioned cationic group-modified PVA used in the emulsion production method of the present invention is as follows:
It is preferably 0.01 to 20 parts by weight. modified with cationic groups
PVA, normal fully saponified PVA, partially saponified PVA
It is also possible to use PVA in combination, and the amount of total PVA used is usually 1 to 20 parts by weight per 100 parts by weight of the ethylenically unsaturated monomer. Further, in the method for producing an emulsion of the present invention, a nonionic surfactant or a cationic surfactant may be added to the emulsion polymerization system as necessary. In particular, when using ethylenically unsaturated monomers other than vinyl acetate, the maximum amount is 5 parts by weight per 100 parts by weight of the ethylenically unsaturated monomer in order to improve the mechanical stability of the emulsion. It is recommended to use it in However, if a large amount of surfactant is used, there are disadvantages such as a decrease in water resistance and a decrease in adhesive strength when an emulsion is used, so care must be taken depending on the purpose. Further, the amount of cationic surfactant to be used must be determined in consideration of toxicity. Examples of nonionic surfactants used in combination include polyoxyethylene alkyl ether,
polyoxyethylene alkyl phenyl ether,
Examples include polyoxyethylene sorbitan fatty acid ester and ethylene oxide-propylene oxide block copolymer. As specific examples of the cationic surfactant, those mentioned above can be used. Additionally, anionic surfactants are generally not recommended due to charge mismatch. Ethylenically unsaturated monomers that can be used in the emulsion production method of the present invention include vinyl esters such as vinyl acetate, vinyl propionate, and vinyl versatate which is a higher fatty acid vinyl ester, methyl acrylate, ethyl acrylate,
Acrylic esters such as butyl acrylate and octyl acrylate, methacrylic esters such as methyl methacrylate and ethyl methacrylate, or vinyl chloride, vinylidene chloride,
Dienes such as acrylonitrile, ethylene, styrene, vinyltoluene, chlorostyrene, α-methylstyrene, acrylamide, N-methylolacrylamide, methacrylamide, maleic acid diester, fumaric acid diester, itaconic acid diester, butadiene, isoprene, etc., or dimethylaminoalkyl acrylate,
Examples include amine-containing monomers such as dimethylaminoalkyl methacrylate, dimethylaminoalkylacrylamide, and dimethylaminoalkylmethacrylamide, or their quaternized products, and 2-hydroxy-3-methacryloxypropyltrimethylammonium chloride, all of which can be homopolymerized or Polymerization is carried out by copolymerization.
Among these, emulsion polymerization using monomers containing vinyl acetate, namely, vinyl acetate homopolymerization, vinyl acetate-ethylene copolymerization, vinyl acetate-acrylic acid ester copolymerization, vinyl acetate-maleic acid ester copolymerization, vinyl acetate- In higher fatty acid vinyl ester copolymerization or vinyl acetate-vinyl chloride copolymerization, PVA modified with cationic groups exhibits particularly excellent emulsion stabilizing effects, and is therefore particularly important among the emulsions obtained by the production method of the present invention. . Furthermore, it is important among the emulsions obtained by the production method of the present invention because good stability can be obtained even in vinyl chloride homopolymerization and (meth)acrylic acid ester homopolymerization or copolymerization with each other. The method for producing the cationic emulsion of the present invention involves adding the above-mentioned ethylenically unsaturated monomer in the presence of water in the presence of the above-mentioned cationic group-modified PVA to peroxide, which is a commonly used polymerization initiator. Hydrogen, potassium persulfide, ammonium persulfide, tertiary hydroperoxide or cumene hydroperoxide, or cationic polymerization initiator 2-azobis-(2-methylpropamidinium) dihydrochloride, 2 -Azobis-
This is carried out by polymerizing with stirring using (2'-isopropylimidazolinium) dihydrochloride or the like. The above polymerization initiators can be used alone, but known redox systems in which the above initiators are combined with reducing agents such as sodium bisulfite, sodium pyrosulfite, sodium metasulfite, and formaldehyde adducts can be used. May be adopted. The amount of these polymerization initiators used is 0.05 parts by weight per 100 parts by weight of ethylenically unsaturated monomer.
The amount is preferably in the range of 5 parts by weight. The emulsion polymerization temperature in the emulsion production method of the present invention is 30 to 120°C, preferably 40 to 90°C, and the pH during polymerization is 3 to 8. As a pH buffering agent, use salts such as sodium carbonate, sodium bicarbonate, sodium orthophosphate, monobasic sodium phosphate, dibasic sodium phosphate, and sodium acetate at 0.05 to 2 parts by weight per 100 parts by weight of the ethylenically unsaturated monomer. It is best to use within the range of parts by weight. In addition, if the cation group in modified PVA is a tertiary amino group, acetic acid,
PH3 by adding formic acid, phosphoric acid, hydrochloric acid or sulfuric acid
It is preferable to adjust it to a range of 8 to 8. The fact that the particles of the emulsion obtained by the production method of the present invention are cationic can be known from the observation of electrophoresis measured by a zetameter, etc., from the fact that the particles move toward the cathode side, and furthermore, the electrophoresis rate ( By measuring the mobility), the streaming potential (zeta potential) can be calculated. The fact that emulsion particles exhibit positive electrophoresis is a fundamental property of emulsions for their cationic properties; however, it is important to note that the magnitude of their streaming potential and various properties that are thought to be due to their cationic properties are not necessarily correlated. The inventors have discovered. In other words, if it is a cation emulsion that simply shows positive electrophoresis, there are a small number of emulsions made by the conventionally known manufacturing method mentioned above, but even if their apparent streaming potentials are the same, this is not the case. The cationic emulsion obtained by the production method of the invention can be easily distinguished from conventionally known cationic emulsions in that it has significantly higher various properties considered to be based on cationic properties. For example, when a liquid prepared by appropriately diluting the emulsion obtained by the production method of the present invention is sprinkled on sand, it is observed that the emulsion immediately reacts with the sand and forms a film on the surface of the sand. Of course, with anionic or nonionic emulsions, this phenomenon is not observed at all, and the emulsion liquid permeates into the sand layer. Furthermore, in commercially available cation emulsions or cation emulsions manufactured by conventionally known production methods, such phenomena are not observed at all, or even if they are observed, their effects are weak. Although it shows the same streaming potential, it is not clear why only the emulsion obtained by the production method of the present invention exhibits such properties and not the conventional cationic emulsion, but This is thought to be based on the use of PVA. As described above, the mechanism by which the cationic emulsion obtained by the production method of the present invention forms a film on the surface of sand is not fully clear, but the surface of sand particles is generally negatively charged in the presence of water. It is thought that this is because when the positively charged emulsion particles come into contact with the sand particles, they react immediately and the emulsion aggregates on the surface of the sand particles. Similarly, the emulsion obtained by the production method of the present invention exhibits an unprecedentedly high adhesive strength to materials that tend to be negatively charged, such as pulp, fibers, and glass. In this sense, the emulsion obtained by the production method of the present invention has a wide range of applications, such as a paper strength enhancer by the beater addition method, a binder for nonwoven fabrics or inorganic materials, a texture improver for textiles, a fiber treatment agent, and household use. Thickening materials, adhesives, cement bonding agents,
Applications include paints, farm mulching, slope reinforcement, and civil engineering and construction materials when blended with asphalt emulsions. EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but these Examples are not intended to limit the present invention in any way. All parts and percentages are by weight unless otherwise specified. Example 1 1400 parts of vinyl acetate and methanol were placed in a reaction tank equipped with a stirrer, thermometer, dropping funnel, and reflux condenser.
2500 parts and N-(3-dimethylaminopropyl)
A mixture of 1.0 part of methacrylamide and acetic acid in a neutralizing amount was placed in a constant temperature bath, and the system was purged with nitrogen while stirring, and the internal temperature was raised to 60°C. 23 parts of 2,2'-azobisisobutyronitrile and 100 parts of methanol were added to this system to initiate polymerization.
During the polymerization time of 2 hours and 40 minutes, 8 parts of N-(3-dimethylaminopropyl) methacrylamide and 32 parts of a methanol solution containing a neutralizing amount of acetic acid were added dropwise to the mixture depending on the solid concentration in the system. The solid content concentration in the system at the time of termination of polymerization was 25.9%. Vinyl acetate monomer remaining in the system was expelled by a conventional method. It was confirmed by nuclear magnetic resonance analysis and nitrogen analysis that this copolymer contained 0.4 mol% of N-(3-dimethylaminopropyl) methacrylamide units and 99.6 mol% of vinyl acetate units. 65% of this copolymer
After adding 79 parts of methyl acetate to 414 parts of methanol solution, 28 parts of 1N caustic soda methanol solution was added thereto while stirring at 40°C to perform a saponification reaction. The resulting gel was crushed, washed with methanol, and dried to obtain a white polymer powder. the resulting denaturation
PVA contained 0.4 mol% of N-(3-dimethylaminopropyl)methacrylamide units, and the degree of saponification of vinyl acetate units was 80 mol%. This degeneration
4% aqueous solution of PVA, viscosity at 20℃ is 7.3cp
(centipoise). (The viscosity was measured using a Burckfield viscometer. The same applies hereinafter.) Next, 80 parts of the modified PVA and 850 parts of distilled water were placed in a reaction tank equipped with a stirrer, thermometer, dropping funnel, and reflux condenser. The temperature was raised with stirring to dissolve the modified PVA, and then the mixture was cooled. The pH of the system was adjusted to 4.0 with 50% aqueous acetic acid while stirring. Next, 1000 parts of vinyl acetate monomer was added, the temperature was raised to 60°C, and the mixture was heated for 2 hours using a hydrogen peroxide aqueous solution and a sodium pyrosulfite aqueous solution.
Emulsion polymerization was carried out for minutes. The cationic polyvinyl acetate emulsion thus obtained had a resin content of 50
%, the viscosity at 25℃ is 98 cp, it has excellent mechanical stability and dilution stability, and the zeta potential measured by an electrophoresis measuring device (zetameter) is +
It was 10.2mV. Example 2 2500 parts of vinyl acetate and methanol were placed in a reaction tank equipped with a stirrer, thermometer, dropping funnel, and reflux condenser.
1000 parts and 2.2 parts of trimethyl-3-(1-methacrylamidopropyl)ammonium chloride were placed in a constant temperature bath, and the system was purged with nitrogen while stirring, and then the internal temperature was raised to 60°C. 3.1 parts of 2,2'-azobisisobutyronitrile and 71 parts of methanol were added to this system to initiate polymerization.
During the polymerization time of 2 hours and 20 minutes, trimethyl-3-(1
-Methacrylamide-propyl) 54 parts of a 25% methanol solution of ammonium chloride was added dropwise according to the solid content concentration in the system. The solid content concentration in the system at the time of termination of polymerization was 39.5%. Vinyl acetate monomer remaining in the system was expelled by a conventional method. This copolymer was saponified in the same manner as in Example 1 to give a white modified color.
Obtained PVA powder. This modified PVA is trimethyl-
It contained 0.4 mol% of 3-(1-methacrylamidopropyl)ammonium chloride units, and the degree of saponification of vinyl acetate units was 80 mol%. The viscosity of this 4% aqueous solution of modified PVA at 20℃ is
It was 20.0cp. Next, in a reaction tank equipped with a stirrer, a thermometer, a dropping funnel, and a reflux condenser, 80 parts of the modified PVA was dissolved in 950 parts of distilled water, and the pH was adjusted to 4.0 with 50% aqueous acetic acid while stirring. . Subsequently, 200 parts of vinyl acetate monomer were added, the temperature was raised to 60°C, 6 parts of a 60% aqueous hydrogen peroxide solution was added, and the temperature was raised to 70°C. While maintaining this temperature, 800 parts of vinyl acetate was continuously added dropwise over 3 hours to carry out emulsion polymerization. 1.5 hours after the start of polymerization, 4 parts of an aqueous hydrogen peroxide solution was added. After dropping vinyl acetate, the temperature was raised to 80°C, held for 30 minutes, cooled to room temperature, and adjusted to pH 6.0 with aqueous ammonia solution.
It was adjusted to The cationic polyvinyl acetate emulsion thus obtained had a viscosity of 510 cp at 25°C at a resin concentration of 50%, excellent mechanical stability and dilution stability, and a zeta potential measured by a zeta meter of +26.4 mV. Ta. Example 3 Trimethyl-3-(1
-Methacrylamide-propyl) A modified PVA containing 0.2 mol% of ammonium chloride units, a degree of saponification of vinyl acetate units of 81 mol%, and a viscosity of 4% aqueous solution at 20°C of 8.6 cp was synthesized. Next, 600 parts of the above modified PVA and distilled water were placed in a pressure-resistant reaction tank equipped with a stirrer, a temperature detection end, and a liquid charging device.
Add 10,000 parts and raise the temperature while stirring to form the above modified PVA.
was dissolved. After cooling, 12,000 parts of vinyl acetate monomer was added to the system with stirring, and the temperature inside the system was raised to 60° C. while ethylene gas was further introduced and the system pressure was adjusted to 45 Kg/cm ² . Add hydrogen peroxide aqueous solution and sodium pyrosulfite aqueous solution at a temperature of 60℃ 3
Emulsion polymerization is carried out for a period of time, and after the polymerization is completed, it is treated with aqueous ammonia solution.
The pH was adjusted to 6.0. The obtained cationic ethylene-vinyl acetate copolymer emulsion had an ethylene unit of 45.4 mol%, a resin concentration of 50%, a viscosity of 61 cp at 25°C, excellent mechanical stability and dilution stability, and a zetameter The zeta potential was +27.0 mV. Example 4 In the same manner as in Example 1, the viscosity at 20°C of a 4% aqueous solution containing 0.6 mol% of N-(3-dimethylaminopropyl)methacrylamide units and having a saponification degree of vinyl acetate units of 79 mol% synthesized a modified PVA of 14.2 cp. Next, a 5.4% aqueous solution of the modified PVA was placed in a pressure-resistant reaction tank equipped with a stirrer, a temperature detection end, and a liquid charging device.
740 parts of vinyl acetate monomer and 800 parts of vinyl acetate monomer were added, and ethylene gas was introduced to adjust the system pressure to 50 Kg/cm ² while the temperature inside the system was raised to 60°C. Polymerization was completed in 2 hours by adding a hydrogen peroxide aqueous solution and a sodium pyrosulfite aqueous solution, and the mixture was cooled to room temperature. The resulting cationic ethylene-vinyl acetate copolymer emulsion contained 46 mol% of ethylene units, a resin concentration of 50%, and 25
Viscosity at °C is 105 cp, mechanical stability,
It had excellent dilution stability, and the zeta potential measured by a zetameter was +28.7 mV. Example 5 Trimethyl-3-(1
-Methacrylamide-propyl) A modified PVA containing 1.5 mol% of ammonium chloride units, a degree of saponification of vinyl acetate units of 70 mol%, and a viscosity of 4% aqueous solution at 20°C of 11.0 cp was synthesized. A 10% aqueous solution of the above modified PVA was placed in a reaction tank equipped with a stirrer, a thermometer, a dropping funnel and a reflux condenser.
450 parts, 9 parts of ethyl acrylate and vinyl acetate
After charging 51 parts and uniformly emulsifying it, 43 parts of 5.7% ammonium persulfate and 46 parts of 13% sodium bisulfite were added to initiate polymerization. While maintaining the temperature in the system at 60° C., a mixture of 81 parts of ethyl acrylate and 459 parts of vinyl acetate and 80 parts of a 2% aqueous ammonium persulfate solution were added dropwise to carry out emulsion polymerization for 3 hours. After dropping, raise the temperature to 70℃, hold for 30 minutes, cool to room temperature, and add 10% ammonia aqueous solution.
The pH was adjusted to 5.0. The resulting cationic vinyl acetate-ethyl acrylate copolymer emulsion has a resin content of 50%, a viscosity of 130 cp at 25°C, and a zeta potential measured by a zetameter of +
It was 11.5mV. Example 6 A 9.6% aqueous solution of modified PVA synthesized in Example 5 was placed in a reaction tank equipped with a stirrer, a thermometer, and a dropping funnel.
450 parts of vinyl acetate, 42 parts of vinyl acetate, and 18 parts of vinyl versatate (manufactured by Ciel, trade name Veova-10).
After uniformly emulsifying the mixture, 43 parts of a 6% aqueous ammonium persulfate solution and 46 parts of a 13% aqueous sodium bisulfite solution were added to initiate polymerization. temperature in the system
While maintaining the temperature at 60° C., a mixture of 378 parts of vinyl acetate and 162 parts of vinyl versatate and 90 parts of a 2% ammonium persulfate aqueous solution were added dropwise to polymerize for 3 hours. After the dropwise addition, the temperature was raised to 70°C and held for 40 minutes, then cooled to room temperature, and the pH was adjusted with 10% ammonia aqueous solution.
was adjusted to 5.0. The resulting cationic vinyl acetate-vinyl versatility copolymer emulsion had a resin content of 50%, a viscosity at 25°C of 98 cp, and a zeta potential measured by a zeta meter of +
It was 28.3mV. Example 7 450 parts of a 10% aqueous solution of modified PVA synthesized in Example 5, 45 parts of vinyl acetate, and di-n maleate were placed in a reaction tank equipped with a stirrer, a thermometer, and a dropping funnel.
- After adding 15 parts of butyl and making it uniformly emulsified,
Polymerization was started by adding 43 parts of a 16% aqueous solution of ammonium persulfate and 48 parts of a 16% aqueous solution of sodium bisulfite. While maintaining the temperature in the system at 60 DEG C., a mixture of 405 parts of vinyl acetate and 135 parts of di-n-butyl maleate and 93 parts of a 2.5% ammonium persulfate aqueous solution were added dropwise to polymerize for 3.5 hours. After dripping, 70
℃, held for 50 minutes, cooled to room temperature, and heated for 10 minutes.
% ammonia aqueous solution to 5.0. The resulting cationic vinyl acetate-maleic acid di-
The resin content of n-butyl copolymer emulsion is 50
%, the viscosity at 25° C. was 95 cp, and the zeta potential measured by a zetameter was +28.4 mV. Example 8 Trimethyl-3-(1
-Methacrylamide-propyl) A modified PVA containing 0.8 mol% of ammonium chloride units, a degree of saponification of vinyl acetate units of 84 mol%, and a viscosity of 4% aqueous solution at 20°C of 13.8 cp was synthesized. Next, in a pressure-resistant container equipped with a stirrer and a temperature detection terminal, 660 parts of a 2.6% aqueous solution of the modified PVA, 500 parts of vinyl chloride monomer, 6 parts of polyoxyethylene nonyl phenyl ether, and 0.9 parts of potassium persulfate were placed.
After polymerizing at 45° C. for 13 hours while stirring in a sealed container, the mixture was cooled to room temperature. The resulting cationic vinyl chloride emulsion had a resin concentration of 30%, a viscosity at 25°C of 26 cp, and a zeta potential measured by a zetameter of +20.5 mV. Example 9 A 10% aqueous solution of modified PVA synthesized in Example 8 was placed in a reaction tank equipped with a stirrer, a thermometer, and a dropping funnel.
420 parts, polyoxyethylene lauryl ether type emulsifier 16 parts, N-methylol acrylamide 0.6
1 part, 29.4 parts of ethyl acrylate, and 30 parts of ethyl methacrylate were charged and uniformly emulsified, and then an emulsion containing 4 parts of a polyoxyethylene lauryl ether type emulsifier and 3 parts of kyumene hydroperoxide was prepared.
Polymerization was started by adding 43 parts of an aqueous solution containing 47 parts of anhydrous sodium pyrophosphate and 3 parts of anhydrous sodium pyrophosphate. While maintaining the temperature in the system at 60°C, add 54 parts of a 10% aqueous solution of N-methylolacrylamide and ethyl acrylate.
264.6 parts of a mixture of 270 parts of methyl methacrylate, 142 parts of an emulsion containing 4 parts of a polyoxyethylene lauryl ether type emulsifier and 1.8 parts of kyumene hydroperoxide, and 1.8 parts of anhydrous sodium pyrophosphate.
Polymerization was carried out for 3 hours while dropping 100 parts of % aqueous solution.
After dropping, the temperature was raised to 70°C, held for 1 hour, cooled to room temperature, and the pH was adjusted to 5.0 with 10% ammonia aqueous solution.
It was adjusted to The resulting cationic ethyl acrylate-methyl methacrylate-N-methylolacrylamide terpolymer emulsion has a resin content of
At 40%, the viscosity at 25°C was 130 cp and the zeta potential was +23.4 mV. Example 10 Trimethyl-3-(1-
A modified PVA containing 3 mol% of methacrylamide-propyl) ammonium chloride units, a degree of saponification of vinyl acetate units of 65 mol%, and a viscosity of 4% aqueous solution at 20°C of 15.5 cp was synthesized. Next, the modified PVA was placed in a reaction tank equipped with a stirrer, a thermometer, a dropping funnel, and a reflux condenser.
930 parts of a 9.3% aqueous solution and 1000 parts of vinyl acetate monomer were charged, the temperature was raised to 60°C, a hydrogen peroxide aqueous solution and a sodium pyrosulfite aqueous solution were added, and polymerization was carried out for 2 hours and 15 minutes. The resulting cationic polyvinyl acetate emulsion has a resin content of 50%, and the viscosity at 25°C is
109 cp, and the zeta potential was +27.5 mV. Comparative Example 1 In Example 1, 20% of a 4% aqueous solution with a saponification degree of 88 mol%, which does not contain a modifying group, was used instead of the modified PVA.
Example 1 using PVA with a viscosity of 8.0 cp at °C
A polyvinyl acetate emulsion was produced in the same manner as above. The resulting emulsion has a resin content of 50%.
The Bruckfield viscosity at 25℃ is 80cp,
The zeta potential was -25.0 mV, indicating anionic properties. Comparative Example 2 Vinyl acetate was emulsion polymerized in the presence of a copolymer of 2-hydroxy-3-methacryloxypropyltrimethylammonium chloride and vinyl acetate to obtain a cationic polyvinyl acetate emulsion. Comparative Example 3 A cationic polyvinyl acetate emulsion was obtained by emulsion polymerization in the presence of polyamide polyamine epichlorohydrin. Comparative Example 4 A cation-resistant latex was obtained by adding an alkylamine/polyoxyethylene surfactant to a carboxyl group-modified styrene-butadiene latex. Example 11 The table below shows the phenomenon when the diluted emulsions (resin content: 10%) obtained in Examples and Comparative Examples were sprinkled on sand. The sand used was Toyoura standard sand.

【table】

【table】

[Table] The film-forming ability on sand of the emulsions obtained in the Examples according to the production method of the present invention is higher than that of the emulsions obtained in Comparative Examples according to the production method different from the production method of the present invention, which have a similar zeta potential. shows a marked difference.

Claims (1)

[Scope of Claims] A method for producing a cationic emulsion, which comprises emulsion polymerizing an ethylenically unsaturated monomer in the presence of a modified polyvinyl alcohol containing a copolymerized unit represented by the following formula (): (Here, A is [Formula] or [Formula] R ¹ , R ² , R ³ are lower alkyl groups (which may contain substituents), and X is a negative group that forms a salt with ammonium nitrogen. 2. The manufacturing method according to claim 1, wherein R ¹ , R ² , and R ³ in the formula () are methyl groups. 3. The manufacturing method according to claim 1 or 2, wherein the ethylenically unsaturated monomer is mainly vinyl acetate. 4. The manufacturing method according to claim 1 or 2, wherein the ethylenically unsaturated monomer is mainly a mixture of vinyl acetate and ethylene. 5. The manufacturing method according to claim 1 or 2, wherein the ethylenically unsaturated monomer is mainly a mixture of vinyl acetate and acrylic ester. 6. The manufacturing method according to claim 1 or 2, wherein the ethylenically unsaturated monomer is mainly a mixture of vinyl acetate and higher fatty acid ester. 7. The manufacturing method according to claim 1 or 2, wherein the ethylenically unsaturated monomer is mainly a mixture of vinyl acetate and maleic acid diester. 8. The manufacturing method according to claim 1 or 2, wherein the ethylenically unsaturated monomer is mainly an acrylic ester and/or a methacrylic ester. 9. The manufacturing method according to claim 1 or 2, wherein the ethylenically unsaturated monomer is mainly vinyl chloride.