JPH0511129B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] This invention uses a high molecular weight copolymer with an average particle size.
The present invention relates to a method for producing a hydrosol that is stably dispersed in water in a range of 0.01 to 0.1 μm. [Prior Art] Conventionally, as a method for producing hydrosol, polymer particles having carboxyl groups obtained by emulsion polymerization method are used, as shown in, for example, Japanese Patent Publication No. 46-22343 and Japanese Patent Application Laid-Open No. 50-19842. (Particle size approx. 0.3~
The so-called strippable method is generally adopted, in which the surface of particles (0.7 μm) is scraped off under high-speed stirring using an alkali such as caustic potash, caustic soda, or ammonium hydroxide to make fine particles with a particle size of approximately 0.01 to 0.1 μm. Ta. However, according to the above-mentioned conventional method, although the film-forming ability is improved due to the micronization, since the emulsifier is mixed into the hydrosol, the water resistance of the resulting film and other molded products deteriorates. Furthermore, there is a limit to the molecular weight of a polymer that can be converted into a hydrosol, and generally, when the weight average molecular weight is 10 ⁴ (10,000) or more, it becomes difficult to form a hydrosol. This naturally limits its application to various uses, and its applications have only been developed mainly in the paint field and paper size processing field. On the other hand, in the field of paints, a method of obtaining a hydrosol by adding an alkali and water to a solution polymer using a hydrophilic organic solvent and stirring and mixing the mixture without using the above-mentioned strippable method was proposed in the Japanese Patent Publication No. 52
This is proposed in Publication No. 47489, etc. According to this method, the water resistance of the film is improved because no emulsifier is used, but on the other hand, since a large amount of organic solvent is used, there are problems in terms of environmental hygiene, pollution, and material cost. Furthermore, because the polymerization process uses a large amount of a hydrophilic organic solvent such as alcohol, the molecular weight of the polymer is low, making it difficult to apply it to applications such as adhesives and films that require high film properties. . Therefore, after extensive study, the inventors have already synthesized a copolymer having an acidic group in the molecule.
An alkaline substance and water are added to this copolymer in a state substantially free of organic solvent or in the presence of a small amount of organic solvent of 20% by weight or less to neutralize some or all of the above acidic groups. At the same time, by inverting the phase from the W/O type (water-in-oil type) to the O/W type (oil-in-water type), the copolymer has an average particle size of
We proposed a method to obtain a hydrosol stably dispersed in water in the range of 0.01-0.1 μm. According to the above-mentioned proposed method, since no emulsifier is required, it is possible to improve the water resistance when used as a film or other molded product, and to increase the molecular weight of the copolymer to a high weight average molecular weight in the range of 10 ⁴ to 10 ⁶ . Since a hydrosol with a stable molecular weight can be obtained, various physical properties when formed into films and other molded products are good, and it can be applied to applications such as adhesives and films.
Furthermore, since a large amount of organic solvent is not used, there are no disadvantages in terms of environmental health, pollution, material cost, etc. [Problems to be Solved by the Invention] However, according to subsequent studies by the inventors, the above proposed method does not allow for successful dispersion of fine particles depending on the type of copolymer and conditions such as alkali neutralization. In some cases, the stability of the dispersed particles was poor, and in particular, an increase in the number of particles over time and the occurrence of aggregates were observed. Therefore, the present invention solves the problems of the above-mentioned proposed method, and enables fine-particle dispersion of copolymers even when there are slight variations in alkali neutralization conditions, etc. In addition to making it easy to
It is an object of the present invention to provide a method for producing a hydrosol that can obtain a hydrosol with improved stability of dispersed particles. [Means for Solving the Problems] As a result of intensive studies to achieve the above object, the inventors neutralized the copolymer with an alkaline substance and water and changed it from the W/O type. O/
When a specific amount of a specific water-soluble polymer substance is added at any stage before the phase inversion to the W type, the copolymer can be easily dispersed into fine particles, and It was discovered that very good results can be obtained in terms of the stability of dispersed particles, and this led to the completion of this invention. That is, the present invention is directed to a monomer having a weight average molecular weight of ¹⁰⁴ to 106, consisting of 0.5 to 20% by weight of an unsaturated monomer having a carboxyl group and 99.5 to 80% by weight of another unsaturated monomer copolymerizable ^therewith. By adding an alkaline substance and water to the copolymer to neutralize some or all of the carboxyl groups in the copolymer molecule and inverting the phase from W/O type to O/W type, In the method for obtaining a hydrosol in which the above-mentioned copolymer is dispersed in water with an average particle size in the range of 0.01 to 0.10 μm, prior to the above-mentioned phase inversion, a nonionic water-soluble polymer substance having an alkylene oxide group and a water-soluble polyurethane resin are prepared. At least one water-soluble polymer substance selected from the above copolymer
This relates to a method for producing a hydrosol, characterized in that 0.01 to 20 parts by weight are added to 100 parts by weight. [Structure and operation of the invention] The copolymer used as a raw material for hydrosol production in this invention is a copolymer of an unsaturated monomer having a carboxyl group and another unsaturated monomer that can be copolymerized with the unsaturated monomer. It is something that can be done. The above unsaturated monomer having a carboxyl group is an essential component for introducing a functional group, that is, a carboxyl group, into the copolymer during hydrosolization, and includes, for example, acrylic acid, methacrylic acid, crotonic acid, Examples include unsaturated carboxylic acids such as itaconic acid, maleic acid, and fumaric acid, and one or more of these monomers can be used. In addition to such unsaturated carboxylic acids, styrene sulfonic acid,
Allylsulfonic acid, sulfopropyl acrylate, 2-acryloyloxynaphthalene-2-sulfonic acid, 2-methacryloyloxynaphthalene-2-sulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, 2-acryloyloxybenzenesulfonic acid, etc. An unsaturated monomer having an acidic group other than a carboxyl group, such as unsaturated sulfonic acid, may be used in combination. The amount of the unsaturated monomer having a carboxyl group is determined in the monomer mixture to obtain the copolymer.
0.5 to 20% by weight, preferably 2 to 10% by weight. If the amount of this monomer used is less than 0.5% by weight, it will be difficult to form a hydrosol;
If it is used in excess of this amount, there is a risk that the film properties, such as adhesive properties such as tackiness and adhesion, may be impaired. Other unsaturated monomers that can be copolymerized with the above unsaturated monomer having a carboxyl group can be selected as appropriate depending on the intended use of the hydrosol, but generally ethyl acrylate, butyl acrylate, and acrylic The main component is (meth)acrylic acid alkyl ester with an alkyl group having a carbon number of 2 to 15, such as 2-ethylhexyl acrylate, isooctyl acrylate, ethyl methacrylate, and butyl methacrylate, and 40% by weight of it as necessary. Those obtained by replacing the following with the following modifying monomers are preferably used. These monomers may be used alone or in combination of two or more, and the amount used is determined in the monomer mixture.
80-99.5% by weight, preferably 90-98% by weight. Examples of the above-mentioned modifying monomers include (meth)acrylic acid alkyl esters in which the number of carbon atoms in the alkyl group is different from that of the main component, such as methyl acrylate and methyl methacrylate, vinyl acetate, acrylonitrile, styrene, and glycidyl acrylate. , glycidyl methacrylate, 2-methoxyethyl acrylate, vinyl ethers, 2-hydroxyethyl methacrylate, acrylamide, N-methylolacrylamide, and the like. A mixture of these monomers can be copolymerized by conventionally known methods such as solution polymerization, emulsion polymerization, suspension polymerization, and bulk polymerization. Particularly preferred are bulk polymerization and solution polymerization using a small amount of solvent. Among these polymerization methods, in the bulk polymerization method, the copolymer obtained by this polymerization method can be used as it is as a raw material for hydrosolization. In the solution polymerization method, if the amount of solvent used is more than 20% by weight, part or all of the organic solvent is removed after polymerization by means such as distillation, but if it is less than 20% by weight, it is converted into a hydrosol as it is. It can be used as a raw material. The organic solvent in this case is preferably an alcoholic water-soluble solvent such as lower alkyl alcohol. Of course, even if it is less than 20% by weight, part or all of it can be removed in the same manner as above. On the other hand, in other polymerization methods, the medium used in each method is removed by appropriate means after synthesis to obtain a solid material substantially free of medium. That is, in the emulsion polymerization method, water is removed by coagulating and separating by salting out, and in the suspension polymerization method, water is removed by filtering the particulate copolymer. In addition,
Some of the emulsifier or dispersant used during polymerization will adhere to the surface of the copolymer particles, but this will be removed during the above-mentioned medium removal operation, and if necessary, it will be almost completely removed by washing several times. Just remove it. In addition, in the emulsion polymerization method, highly three-dimensional copolymers, so-called gelled products, may be produced, but such copolymers can be an obstacle to hydrosolization, and are It is desirable to prevent the formation of this copolymer as much as possible during heating.
However, even if a small amount of this type of copolymer is produced, it can be solved by masticating using a mixing roll, a Banbury mixer, etc., and applying a high shearing force. It is necessary that the weight average molecular weight of the copolymer thus obtained is designed to be in the range of 10 ⁴ to 10 ⁶ . If this molecular weight is less than 10 ⁴ , there is a risk that the strength of the hydrosol film will be poor, or that adhesive coatings will have poor adhesion, while if this molecular weight exceeds 10 ⁶ , it will be difficult to form a hydrosol into a film. Both of these methods are unsuitable because they cause unfavorable results in terms of film properties and other film properties. In this invention, the copolymer obtained in this way is heated in an alkaline state while stirring in a state substantially free of organic solvent or in a state containing 20% by weight or less of an organic solvent as described above. Add the substance and water to neutralize some or all of the carboxyl groups in the copolymer molecules, and add W/
By inverting the phase from O type to O/W type, a hydrosol in which the above copolymer is dispersed in water with an average particle size in the range of 0.01 to 0.1 μm is obtained. The method of proceeding with the neutralization and phase inversion described above to obtain this hydrosol can be arbitrarily selected. Preferably, the above-mentioned copolymer is first neutralized by adding a predetermined amount of an alkaline substance and water, and then, in the second step, water is gradually added to invert the phase to O/W type. It is better to adopt this method (hereinafter referred to as the two-step operation method). For this two-step operation method, all the necessary amount of water is added in the first step above, and the O/
A method of inverting the phase to a W-type, that is, omitting the second step described above (hereinafter referred to as the one-step operation method)
Of course, it is also possible to adopt In each of these operating methods, the alkaline substances used for neutralization include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, amines such as ethylamine and propylamine, ammonia, and α-aminoethyl hydroxide. Alcohol, etc. Among these, readily volatile alkaline substances such as ammonia are particularly preferred. This is because it can be easily volatilized and removed by heating when forming a film etc. from hydrosol.
This is because adverse effects on film properties such as adhesive properties can be reduced. The amount of this alkaline substance to be used may be generally 0.02 to 2 equivalents relative to the carboxyl groups of the copolymer. The temperature during the neutralization treatment can be appropriately set depending on the type and properties of the copolymer, and is generally preferably in the range of 30 to 95°C. The amount of water required for final phase inversion to O/W type cannot be determined unconditionally depending on the type of copolymer, but in general,
Within the range of 70 to 10,000 parts by weight per 100 parts by weight,
It can be appropriately selected depending on the desired solid content concentration of the hydrosol. Now, a major feature of this invention is that a specific water-soluble polymeric substance is added during such hydrosolization in order to disperse the copolymer into particles and stabilize the dispersed particles. . The water-soluble polymeric substance is at least one selected from nonionic water-soluble polymeric substances having alkylene oxide groups and water-soluble polyurethane resins. Such water-soluble polymer substances have the effect of lowering the surface tension of water when dissolved in water, and lowering the interfacial tension between the copolymer and water. becomes wettable with water, promoting fine particle dispersion. Furthermore, the polymer substance is adsorbed on the surface of the dispersed particles and acts as a protective colloid for the particles, making the dispersed particles extremely stable. In this way, the above specific water-soluble polymeric substance is
Regardless of the type of copolymer, especially if the copolymer is highly hydrophobic, the conditions for alkali neutralization may vary depending on the surface tension lowering ability and protective colloid ability of water. This also facilitates the particle dispersion of the copolymer and greatly contributes to the stabilization of the dispersed particles. Moreover, such a water-soluble polymer substance has the feature that there is no risk of adversely affecting the water resistance when the obtained hydrosol is formed into a film, and the excellent water resistance inherent to the hydrosol can be maintained. ing. Note that, as water-soluble polymeric substances, polyvinyl alcohol, carboxymethyl cellulose, sodium parylate acrylate, etc., which have the same protective colloid ability as described above, are known. However, when these polymeric substances are used as additives in the hydrosol of the present invention, they have a tendency to have an adverse effect on the fluidity of the hydrosol, and in particular to cause high thixotropy and thicken the hydrosol, thereby adversely affecting the stability of the hydrosol. can be seen. Moreover, such polymeric materials have the problem of extremely low water resistance when formed into a film. The nonionic water-soluble polymer substance having an alkylene oxide group used in this invention has the following general formulas (1) and (2); R-O(-CmH ₂ mO) _o --H...( 1) R-O(-CmH ₂ mO) _o --R ......(2) mono(or di)alkyl ethers of polyalkylene glycol, or the following general formulas (3), (4); RCO -O(-CmH ₂ mO) _o --H...(3) RCO-O(-CmH ₂ mO) _o --OCR...(4) Polyalkylene glycol mono(or di)alkyl esters Examples include. R in each general formula has 1 to 20 carbon atoms, preferably 6
In addition to the alkyl group of ~18, it may also be an alkenyl group having the same number of carbon atoms, or an alkyl group or phenyl group substituted with an alkenyl group having the same number of carbon atoms. Moreover, m is an integer of 2 to 4, and specific examples of the alkylene oxide group represented by C _n H _2n O include ethylene oxide group, propylene oxide group, and butylene oxide group. Furthermore, n in each general formula is an integer from 20 to 30000,
The weight average molecular weight of the entire polymer substance ranges from several thousand to several tens.
Preferably, it is set within a range of 10,000. If the molecular weight is too high, the hydrophilicity will decrease, and if it is too low, the water resistance will decrease when the hydrosol is formed into a film, so neither is preferable. Specific examples of such nonionic water-soluble polymer substances include mono(or di)alkyl ethers such as polyethylene glycol mono(or di)alkyl ethers and polypropylene glycol mono(or di)alkyl ethers, polyethylene glycol mono(or di)laurate,
Examples include mono(or di)alkyl esters such as polyethylene glycol mono(or di)stearate, polypropylene glycol mono(or di)stearate, and polypropylene glycol mono(or di)laurate. Among the above-mentioned nonionic water-soluble polymer substances, polymer substances with OH or OR groups at the end of the molecule are highly hydrophilic, and polymer substances with an OCOR group at the end of the molecule are difficult to coat when formed into a film. This gives better results in terms of water resistance. The water-soluble polyurethane resin used in this invention has the following general formula (5); [-(-CmH ₂ mO) _o --CONH-R-NHCOO] _l --
...(5) Those made from a water-soluble polyol represented by the following general formula (6); Examples include cationic water-soluble polyurethane resins obtained by introducing tertiary amino groups into hydrophobic aliphatic polyols represented by the following. m in both formulas (5) and (6) above is an integer of 2 to 4, R,
R' and R'' are a lower alkylene group having 2 or more carbon atoms or a group having an aromatic ring, R is an alkyl group or alkenyl group having 1 to 6 carbon atoms, or a phenyl group that may have a substituent, etc.; , n is the weight average molecular weight of the entire polymer substance from several thousand to several tens.
It is an integer set to be in the range of 10,000. The reason for setting the molecular weight within the above range is the same as in the case of the nonionic polymer substance. In this invention, one kind of water-soluble polymer substances and water-soluble polyurethane resins having such alkylene oxide groups may be used, or two or more kinds thereof may be used as a mixture. In the case of a mixed system, two or more of the former polymeric substance and the latter polyurethane resin may be selected and used from one or both of them. The amount of such a water-soluble polymer substance to be used should be 0.01 to 20 parts by weight per 100 parts by weight of the copolymer to be hydrosolized, and preferably
The amount is preferably 0.1 to 10 parts by weight. If the amount is less than 0.01 part by weight, the effect of the present invention cannot be sufficiently obtained, and if it is more than 20 parts by weight, the stability of the dispersed particles will decrease, so both are unsuitable. The optimum amount to be used varies depending on the hydrophilicity of the water-soluble polymer, the ability to lower the surface tension of water, and the hydrophobicity of the copolymer to be hydrosolized. It is desirable to set it appropriately. The above-mentioned water-soluble polymeric substance should be added at a stage before phase inversion in a series of hydrosolization steps consisting of neutralization and phase inversion. That is,
Even if it is added after being hydrosolized by phase inversion, it will not be possible to sufficiently improve the dispersion of fine particles and the stabilization of dispersed particles, which are the objectives of this invention, and on the contrary, the resulting hydrosol will become thicker, etc. The result is accompanied by undesirable phenomena. As long as it is added at a stage before phase inversion, the timing of its addition is not particularly critical. For example, in the hydrosolization using the two-step operation method, in the first step of adding an alkaline substance and water for neutralization, the alkaline substance and water are added before or at the same time, or after the addition, that is, the neutralization process is performed. It can be added after doing this. In addition, in the hydrosolization using the one-step operation method, the alkaline substance and water may be added before or at the same time. The hydrosol obtained in this way consists of a copolymer stably dispersed in water with an average particle size in the range of 0.01 to 0.1 μm, the solid content concentration is usually about 1 to 50% by weight, and the viscosity is at 25℃
It is about 0.1 to 1000 poise. It should be noted that various additives such as tackifiers, softeners, plasticizers, crosslinking agents, fillers, and colorants can be added to this hydrosol at any stage before or after hydrosolization. Needless to say. [Effects of the Invention] As described above, in this invention, a specific amount of a specific water-soluble polymer substance is added during hydrosolization, so that the copolymer to be hydrosolized is hydrophobic. Even if the hydrosolization conditions are high and the hydrosolization conditions vary slightly,
The copolymer can be dispersed into particles easily and in a short time, and a hydrosol can be obtained that has excellent stability of the dispersed particles and is less likely to thicken over time or generate aggregates. Additionally, because the copolymer used in this hydrosol has a high molecular weight and is dispersed in extremely fine particles, this hydrosol can form films with excellent film-forming properties and physical properties such as mechanical strength. grant,
Moreover, molded products such as these films are characterized by excellent water resistance. [Examples] Below, examples of the present invention will be described in more detail. In the following, parts and % mean parts by weight and % by weight, respectively. The weight average molecular weight of the copolymer means the value measured by GPC (gel permeation chromatography), and the viscosity of the copolymer means the value measured by a Bruckfield viscometer (rotor No. 29, 1 rpm). Furthermore, the average particle size of the hydrosol particles is determined by the nanosizer, and the viscosity of the hydrosol is
Means the value measured by a BH type viscometer (rotor No. 6, 10 rpm). Example 1 10 parts of a monomer mixture consisting of 90 parts of n-butyl acrylate, 10 parts of styrene, and 4 parts of methacrylic acid and 5 parts of sec-butanol were charged into a four-necked flask and stirred. While the inner bath temperature is 40℃
The air was replaced with nitrogen for 40 minutes. Then, after adding 0.1 part of benzoyl peroxide and completely dissolving it,
The reaction was started by raising the temperature to 80°C, and the remaining monomer mixture was added dropwise from the dropping funnel over a period of about 2 hours.
The reaction was carried out for 4 hours while maintaining the reaction temperature at 85±5°C. The copolymer thus obtained had a weight average molecular weight of 4.1×10 ⁵ and a viscosity of 5100 poise at 80°C. A 25% aqueous solution of a nonionic water-soluble polymer substance (trade name Unisafe UI1300, manufactured by NOF Corporation; represented by the above general formulas (2) and (4)) was added to 100 parts of this copolymer at a temperature of 80°C. Mixture) 5 parts were added and mixed. Next, 0.8 equivalent of ammonia based on the carboxyl group contained in the above copolymer and water in a ratio of 170 parts to 100 parts of the copolymer were added to this mixture, and the mixture was heated to a temperature of 70±3°C. A hydrotosol in which the continuous phase was water was obtained by neutralization and phase inversion. This hydrosol has a solids concentration of 33
%, the viscosity at 25° C. was 87 poise, and the average particle diameter of the dispersed particles was 0.06 μm. Example 2 Polymerization was carried out in the same manner as in Example 1 using 80 parts of 2-ethylhexyl acrylate, 20 parts of ethyl acrylate, 2.5 parts of methacrylic acid, and 0.05 parts of lauryl mercaptan, so that the polymerization average molecular weight was
A copolymer having a density of 3.7×10 ⁵ and a viscosity (80° C.) of 3800 poise was obtained. Polyethylene glycol distearate (weight average molecular weight 10,000) is added to 100 parts of this copolymer.
1.0 part was added and mixed at 80°C. Next, 1.4 equivalents of ammonia with respect to the carboxyl group contained in the above copolymer and water in a ratio of 280 parts with respect to 100 parts of the copolymer were added to this mixture, and the mixture was heated to a temperature of 70±3°C. By neutralization and phase inversion below, a hydrosol with water as the continuous phase was obtained. This hydrosol has a solids concentration of 27
%, the viscosity at 25° C. was 16 poise, and the average particle diameter of the dispersed particles was 0.08 μm. Example 3 To 100 parts of a copolymer obtained in the same manner as in Example 1,
At a temperature of 70±3°C, 0.8 equivalent of ammonia water (25%
water-soluble polyurethane resin (trade name: Coraclar, manufactured by BASF).
Three parts of a 25% aqueous solution of PU-85 (the main component of which is represented by the general formula (5)) was added and mixed. Subsequently, 170 parts of water was gradually added and phase inversion was carried out to obtain a hydrosol in which copolymer particles were stably dispersed in water. This hydrosol had a solid content concentration of 34 parts, a viscosity at 25° C. of 52 poise, and an average particle diameter of 0.07 μm. Comparative Example 1 Example 1 was prepared without adding a nonionic water-soluble polymer substance to the copolymer obtained in the same manner as in Example 1.
A hydrosol was obtained by performing the same neutralization treatment and phase inversion. This hydrosol has a solid content concentration of 32%,
The viscosity at 25° C. was 23 poise, and the average particle diameter of the dispersed particles was 0.09 μm. Comparative Example 2 To the hydrosol obtained in Comparative Example 1, 5 parts of a 25% aqueous solution (same as in Example 1) of a nonionic water-soluble polymer substance was added and mixed with respect to 100 parts of the copolymer. The viscosity of the hydrosol after this mixing at 25°C was 340 poise. Comparative Example 3 To 100 parts of a copolymer obtained in the same manner as in Example 1,
After adding and mixing 18 parts of a 7% polyvinyl alcohol (saponification degree 99%) aqueous solution at a temperature of 80°C,
A hydrosol was obtained by performing the same neutralization treatment and phase inversion as in Example 1. The solid content concentration of this hydrosol was
31% by weight, the viscosity at 25°C was 840 poise, and the average particle diameter of the dispersed particles was 0.09 μm. The results of examining changes in appearance, viscosity, and mechanical stability of each hydrosol obtained in the above Examples and Comparative Examples after storage at 30°C for one month, as well as the water resistance of the film formed from each hydrosol. The results of examining the characteristics were as shown in the table below. In the table, A is before storage (initial stage) and B is after storage at 30°C for one month. The mechanical stability and water resistance were measured and evaluated using the following methods. <Mechanical stability> Sample (hydrosol) 50
The weight percent of aggregates produced after the test was measured under conditions of 20 kg load, 5 minutes time. <Water Resistance> Each hydrosol was applied onto a glass plate using a coating rod, and then heated and dried at 110°C for 10 minutes to form a film with a thickness of 50 μm. This film
It was immersed in water at 40°C for a predetermined period of time to examine changes in its properties.

[Table] As is clear from the above results, according to the method of the present invention, it is easy to disperse the copolymer into fine particles, the stability of the dispersed particles is excellent, and a film with good water resistance is formed. It turns out that it is possible to produce hydrosols that can be used.

Claims (1)

[Claims] 1 Unsaturated monomer with carboxyl group 0.5~
20% by weight and other unsaturated monomers copolymerizable with it
Weight average molecular weight 10 ⁴ ~ 99.5 ~ 80% by weight
10 Adding an alkaline substance and water to the copolymer of ⁶ to neutralize some or all of the carboxyl groups in the copolymer molecule and inverting the phase from W/O type to O/W type. In the method for obtaining a hydrosol in which the above-mentioned copolymer is dispersed in water with an average particle size in the range of 0.01 to 0.10 μm, prior to the above-mentioned phase inversion, a nonionic water-soluble polymeric substance having an alkylene oxide group and a water-soluble At least one water-soluble polymer substance selected from polyurethane resins is added to 100 parts by weight of the copolymer.
A method for producing a hydrosol, characterized by adding 0.01 to 20 parts by weight.