JPS6314723B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel aqueous dispersion solution of a urethane-modified vinyl polymer and a method for producing the same.
It has excellent stability and can form a film with excellent water resistance and weather resistance, and can be used for example in water-based paints, water-based inks, water-based coating agents, processing agents for paper and fibers, dispersants, etc. The present invention provides an aqueous dispersion solution that can be used as a dispersion solution.

Aqueous dispersion solutions of urethane polymers include polyurethane dispersed in water using an emulsifier or dispersant, or polyurethane with hydrophilic groups (including ionic groups) introduced into the polyurethane chain in advance. Although there are dispersed solutions, all of the conventionally used aqueous dispersions have the disadvantage that they have insufficient stability and the films formed have poor water resistance and weather resistance.

In contrast, the first invention provides an aqueous dispersion of a urethane-modified vinyl polymer that does not have the above-mentioned drawbacks, and the second invention provides an aqueous dispersion of a urethane-modified vinyl polymer that does not have the above-mentioned drawbacks. The present invention provides a method for efficiently, reliably, and easily obtaining an aqueous dispersion solution.

The configuration of the present invention will be explained below.

The aqueous dispersion solution of the urethane-modified vinyl polymer of the present invention is a reaction product of a vinyl polymer having hydroxyl groups and carboxyl groups and a urethane prepolymer having terminal isocyanate groups, and has an acid value of 20.
The above urethane-modified vinyl polymer is dispersed in an aqueous solvent containing an alkaline substance.

In the present invention, it is an essential component that the urethane-modified vinyl polymer used has an acid value of 20 or more. This is because if the acid value of the urethane-modified vinyl polymer used is less than 20, it will not be possible to obtain an aqueous dispersion solution with sufficient stability, which is the objective of the present invention. On the other hand, the upper limit of the acid value of the urethane-modified vinyl polymer is not particularly limited, but if the acid value exceeds 200, a coating film formed from an aqueous dispersion solution may be used. However, it is preferable to use a urethane-modified vinyl polymer having an acid value of 200 or less.

A vinyl polymer having a hydroxyl group and a carboxyl group can be obtained by copolymerizing a monomer having a hydroxyl group, a monomer having a carboxyl group, and other monomers that can be copolymerized with these monomers. It is easily manufactured by.

Examples of monomers having hydroxyl groups include hydroxyalkyl (meth)acrylates such as hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, and hydroxybutyl (meth)acrylate, polyethylene glycol mono(meth)acrylate, and allyl Alcohols, hydroxystyrenes, etc., and monomers having carboxyl groups include, for example, α,β-unsaturated monobasic acids such as acrylic acid, methacrylic acid, and crotonic acid, maleic acid, fumaric acid, itaconic acid, etc. α,β-unsaturated polybasic acids and half esters thereof, etc. can be used. Furthermore, other monomers that can be copolymerized with these monomers include, for example, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and lauryl (meth)acrylate. ) Alkyl (meth)acrylates such as acrylates, vinyl esters such as vinyl acetate and vinyl propionate, aromatic monovinyl compounds such as styrene and vinyltoluene, allylsulfonic acid,
Monovinyl sulfonic acids such as styrene sulfonic acid, vinyl ethers, allyl ethers, etc. can be used.

Of course, each of the monomers having a hydroxyl group, the monomers having a carboxyl group, and other monomers copolymerizable with these monomers may be used as single compounds. Yes, but
It can also be used in the form of a mixed compound in which several types of compounds are mixed.

When obtaining this vinyl polymer having a hydroxyl group and a carboxyl group, each of a monomer having a hydroxyl group, a monomer having a carboxyl group, and other monomers copolymerizable with these monomers is used. When an acrylic polymer is obtained as a vinyl polymer having a hydroxyl group and a carboxyl group by selecting and using a (meth)acrylic monomer, it is used as a vinyl polymer having a terminal isocyanate group. A urethane-modified vinyl polymer obtained by reacting with a urethane prepolymer has particularly excellent weather resistance.

The vinyl polymer is prepared by adding each of the above-mentioned monomers, that is, a monomer having a hydroxyl group, a monomer having a carboxyl group, and other monomers copolymerizable with these monomers, in a conventional manner. It is easily produced by subjecting it to a polymerization operation such as bulk polymerization, suspension polymerization, emulsion polymerization, or solution polymerization, but in particular, it is reacted with the obtained vinyl polymer in the steps described below. Ester solvents such as ethyl acetate and formate, acetone, methyl ethyl ketone, etc. that have the effect of dissolving urethane prepolymers having terminal isocyanate groups and do not show reactivity with hydroxyl groups, carboxyl groups, and isocyanate groups. Utilizing a solution polymerization reaction using a solvent such as a ketone solvent, dimethylformamide, or dimethyl sulfoxide allows the obtained vinyl polymer to be combined with another reaction component, a urethane prepolymer having terminal isocyanate groups. In the reaction step, the solution of the vinyl polymer can be used as it is, which is convenient in terms of operational steps.

In the vinyl polymer obtained by copolymerization of a monomer having a hydroxyl group, a monomer having a carboxyl group, and another monomer copolymerizable with these monomers in the present invention, The amount of hydroxyl groups contained in the vinyl polymer is not particularly limited; If is small, the amount of urethane prepolymer that reacts with the vinyl polymer will be relatively small, which may make it impossible to obtain an aqueous dispersion solution having the ability to form a film with the properties targeted by the present invention. Therefore, it is desirable that the hydroxyl value is preferably 30 or more. On the other hand, when the hydroxyl group value contained in the vinyl polymer is high, it is possible to react the urethane prepolymer with a portion of the hydroxyl groups in the vinyl polymer, and the resulting urethane-modified vinyl polymer The unreacted hydroxyl groups in the polymer have the effect of further improving the stability of the aqueous dispersion of the polymer. However, if the hydroxyl value is
If it is as high as 200 or more, it will cause a decrease in the water resistance of the coating film formed from the aqueous dispersion, so for this reason it is desirable that the hydroxyl value is 200 or less. On the other hand, the amount of carboxyl groups contained in the vinyl polymer depends on the acid value of the urethane-modified vinyl polymer, which is the reaction product with the urethane prepolymer having terminal isocyanate groups, which is another reaction component mentioned above. Since it has a direct influence, it is desirable that the amount is such that the acid value of the urethane-modified vinyl polymer is 20 to 200, that is, the acid value is within the range of about 30 to 250.

The urethane prepolymer having a terminal isocyanate group to be reacted with the vinyl polymer having a hydroxyl group and a carboxyl group has at least one isocyanate group at the terminal, and the reaction between the polyhydroxy compound and the polyisocyanate compound Preference is given to using a product urethane prepolymer.

Specific examples of polyhydroxy compounds include:
Polyethylene glycol, polypropylene glycol, ethylene oxide-propylene oxide block copolymer, polyether polyols such as poly(tetramethylene ether) polyol, polyester polyols, ethylene glycol, 1,4-butanediol, 1,
Alkylene glycols such as 6-hexanediol can be used alone or in mixtures.

Specific examples of the polyisocyanate compound include tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, isophorone diisocyanate, and prepolymers thereof, singly or in mixtures.

When obtaining a urethane prepolymer, a urethane prepolymer having isocyanate groups at both ends can be obtained by reacting a dihydroxy compound and a diisocyanate compound with an appropriate excess proportion of isocyanate groups, or a trifunctional or higher functional polyhydroxy compound or polyisocyanate compound. By reacting, a urethane prepolymer having three or more terminal isocyanate groups can be obtained, but if these urethane prepolymers are reacted with the above-mentioned vinyl polymer, there is a disadvantage that gelation occurs due to crosslinking reaction. In such a case, it is preferable to use a blocking agent to suppress the number of terminal isocyanate groups in the urethane prepolymer to about 1 to 1.5 on average. This blocking agent can be used at any stage when reacting a polyhydroxy compound and a polyisocyanate compound to obtain a urethane prepolymer, or when reacting the obtained urethane prepolymer with a vinyl polymer. . This blocking agent can be one having one functional group reactive with isocyanate groups, such as alcohols, phenols, thiols, amines, etc. When used to obtain a urethane prepolymer, It is preferable to obtain a urethane prepolymer by using a suitable solvent and a suitable urethanization reaction catalyst and performing a normal polyurethane synthesis reaction.

The urethane-modified vinyl polymer in the present invention is a urethane-modified polymer with an acid value of 20 or more obtained by reacting the above-described vinyl polymer having hydroxyl groups and carboxyl groups with a urethane prepolymer having terminal isocyanate groups. It is a vinyl polymer, and the vinyl polymer and urethane prepolymer are mixed at a desired mixing ratio, preferably 1 equivalent or less of the terminal isocyanate group of the urethane prepolymer per 1 equivalent of hydroxyl group of the vinyl polymer, especially It is obtained by mixing 1 to 1/5 equivalents and subjecting the mixture to a heating reaction.

In this reaction between the vinyl polymer and the urethane prepolymer, the terminal isocyanate group of the urethane prepolymer preferentially reacts with the hydroxyl group of the vinyl polymer, and the urethane-modified vinyl polymer having carboxyl groups in the present invention reacts preferentially with the hydroxyl group of the vinyl polymer. However, the reaction between the vinyl polymer and the urethane prepolymer is carried out in a solvent that uniformly dissolves both of these reaction components and does not show reactivity with the functional groups of each reaction component. It is preferable to carry out the reaction in such a manner that the reaction can proceed smoothly. The end point of the reaction is the point at which the free isocyanate groups contained in the reaction mixture are substantially exhausted, but the presence of small amounts of free isocyanate groups in the reaction product does not pose any particular hindrance. In addition, the above-mentioned blocking agent can be added if necessary.

In the aqueous dispersion solution of the urethane-modified vinyl polymer of the present invention, the urethane-modified vinyl polymer having an acid value of 20 or more as described above at least partially neutralizes the carboxyl groups in the urethane-modified vinyl polymer. It is dispersed in an aqueous solvent, ie, water or a mixture of water and a hydrophilic solvent, containing a suitable amount of an alkaline substance.

An aqueous dispersion solution in which a urethane-modified vinyl polymer is dispersed in water containing an alkaline substance or an aqueous solvent consisting of water and a hydrophilic solvent is prepared by mixing the urethane-modified vinyl polymer in an aqueous solvent, It can be obtained by adding an alkaline substance to this, or by mixing the urethane-modified vinyl polymer into an aqueous solvent to which an alkaline substance has been added in advance. Also, when using a solvent solution of the polymer as the urethane-modified vinyl polymer, similarly, this solvent solution is mixed as it is in an aqueous solvent, and then an alkaline substance is added to this mixed solution. Alternatively, a solvent solution of a urethane-modified vinyl polymer is mixed in an aqueous solvent to which an alkaline substance has been added in advance, and the resulting mixed solution is then subjected to vacuum distillation to remove the organic solvent in the mixed solution. obtained by removing,
In particular, in the former method in which the solvent solution of the urethane-modified vinyl polymer is directly mixed into the aqueous solvent, the vacuum distillation operation for removing the organic solvent is performed even before adding the alkaline substance to the mixed solution. Alternatively, the step may be carried out separately, before and after adding the alkaline substance.

As mentioned above, the alkaline substance present in the aqueous dispersion of the urethane-modified vinyl polymer of the present invention is one that at least partially neutralizes the carboxyl groups in the urethane-modified vinyl polymer with an acid value of 20 or more. This imparts dispersibility in an aqueous solvent to the urethane-modified vinyl polymer. This alkaline substance includes inorganic and organic alkaline substances such as methylamine,
Examples include alkylamines such as ethylamine, dimethylamine, and triethylamine, alkanolamines such as monoethanolamine, diethanolamine, dimethylethanolamine, and methyldiethanolamine, caustic soda, caustic potash, and ammonia, but especially ammonia, lower alkyl amines, and lower alkanols. When an aqueous dispersion solution obtained using a volatile alkaline substance such as an amine is formed into a film, the alkaline substance volatilizes, resulting in a film with excellent water resistance.

The aqueous dispersion solution of a urethane-modified vinyl polymer and the method for producing the same of the present invention are constructed as described above, in which the urethane-modified vinyl polymer dispersed in an aqueous solvent is The aqueous dispersion solution of the present invention has excellent self-dispersibility due to its carboxyl group, and the polyurethane segment of the polymer is protected by a stable vinyl polymer. The dispersion solution has the characteristics that it has excellent stability and that a coating film with excellent water resistance and weather resistance can be obtained from this dispersion solution. In addition, since the production method involves carrying out the reaction in a solvent, the reaction proceeds smoothly and has the effect that the dispersion solution, which is the object of the present invention, can be produced reliably and easily. .

Hereinafter, an aqueous dispersion solution of a urethane-modified vinyl polymer of the present invention, the functions and effects of the solution, and an example of a method for producing the solution will be explained based on Examples and Comparative Examples.

Example 1 (i) Production of vinyl polymer having hydroxyl group and carboxyl group 200 g of ethyl acetate was charged into a 500 ml four-necked flask, heated and maintained at reflux temperature. While passing nitrogen gas, 206 g of a mixed monomer solution consisting of 30 g of acrylic acid, 30 g of 2-hydroxyethyl acrylate, 30 g of 2-ethylhexyl acrylate, 110 g of methyl methacrylate, 2 g of thioglycolic acid, and 4 g of azobisisobutyronitrile was added over 3 hours. drip. After the dropwise addition was completed, the temperature was maintained for another 4 hours to obtain 393 g of an ethyl acetate solution of vinyl polymer (A).

The vinyl polymer (A) has an acid value of 119 and a hydroxyl value of 70.

(ii) Production of urethane prepolymer having terminal isocyanate groups A 500 ml four-necked flask was charged with 100 g of ethyl acetate and 56.7 g of polyethylene glycol (molecular weight 300), and tolylene diisocyanate (TDI) was prepared at room temperature.
41.1g was administered. After the exotherm stopped, the reaction was carried out at 40 to 50°C for 1 hour, and then 2.2 g of ethanol was added and the reaction was carried out at the same temperature for an additional hour. Subsequently, 0.06 g of dibutyltin dilaurate was added, and after the heat generation had stopped, the reaction was carried out at 50 to 60°C for about 1 hour to form a urethane prepolymer (B) having terminal isocyanate groups.
200 g of an ethyl acetate solution was obtained. The reaction component ratio of this urethane prepolymer (B) is polyethylene glycol: TDI: ethanol = 4:5:1 (molar ratio)
and has an average of one terminal isocyanate group.

(iii) Production of urethane-modified vinyl polymer In a 500 ml four-necked flask, add 48 g of the ethyl acetate solution of the vinyl polymer (A) obtained in section (i) above and the same solution obtained in section (ii) above. Ethyl acetate solution of urethane prepolymer (B) with terminal isocyanate groups
After charging 100 g and reacting at 70 to 80° C. for 2 hours, 4 g of ethanol was added and the reaction was further continued for 30 minutes to obtain an ethyl acetate solution of urethane-modified vinyl polymer (C).

The reaction ratio of urethane prepolymer/vinyl polymer in this reaction is approximately 2/1 by weight.
The equivalent ratio of NCO/OH was about 1/1.33, and the acid value of the obtained urethane-modified vinyl polymer (C) was about 40.

(iv) Preparation of aqueous dispersion solution of urethane-modified vinyl polymer The ethyl acetate solution of the urethane-modified vinyl polymer obtained in section (iii) above was subjected to a distillation operation to remove a portion of the ethyl acetate. . Next, 5.5 g of dimethylethanolamine and 175 g of water were added, thoroughly stirred and dispersed, and then distilled under reduced pressure at about 70°C for 1 hour to remove the remaining ethyl acetate, and further diluted with water to give a polymer concentration of 30%. An aqueous dispersion solution (PH7.4) of a urethane-modified vinyl polymer was obtained.

The resulting aqueous dispersion of the urethane-modified vinyl polymer has very good stability, and the film obtained by coating this dispersion on a glass plate and drying it is colorless, transparent, water resistant, It had excellent weather resistance.

Example 2 (i) Production of a vinyl polymer having hydroxyl groups and carboxyl groups In the operation in item (i) of Example 1, 20 g of acrylic acid, 40 g of 2-hydroxyethyl acrylate, 2- The same procedure as in section (i) of Example 1 was carried out except for using a mixed monomer solution consisting of 20 g of ethylhexyl acrylate, 80 g of methyl methacrylate, 40 g of styrene, 2 g of thioglycolic acid, and 4 g of azobisisobutyronitrile. Ethyl acetate solution of vinyl polymer (D)
Obtained 391g.

The vinyl polymer (D) has an acid value of 81 and a hydroxyl value of 94.

(ii) Production of urethane prepolymer having terminal isocyanate groups In a 500 ml four-necked flask, add 100 ml of ethyl acetate.
g, polyethylene glycol (molecular weight 200) 38.3
g, prepare 7g of trimethylpentanediol,
After uniformly mixing and dissolving, 52 g of TDI was added dropwise at room temperature. Following the same procedure as in section (ii) of Example 1, 200 g of an ethyl acetate solution of the urethane prepolymer (E) having terminal isocyanate groups was obtained using 2.8 g of ethanol and 0.06 g of dibutyltin dilaurate.

The reaction component ratio of this urethane prepolymer (E) is
Polyethylene glycol: trimethylpentanediol: TDI: ethanol = 3.2:0.8:5:1 (mole ratio), and has one terminal isocyanate group on average.

(iii) Production of urethane-modified vinyl polymer 47.5 g of an ethyl acetate solution of the vinyl polymer (D) obtained in the above (i) and the urethane prepolymer (E) obtained in the above (ii) ) in ethyl acetate solution 100g,
The same operation as in section (iii) in Example 1 was performed using 5 g of ethanol and 5 g of ethanol to obtain an ethyl acetate solution of the urethane-modified vinyl polymer (F).

The reaction ratio of urethane prepolymer/vinyl polymer in this reaction is approximately 2/1 by weight.
The equivalent ratio of NCO/OH was about 1/1.4, and the acid value of the obtained urethane-modified vinyl polymer (F) was about 27.

(iv) Preparation of an aqueous dispersion solution of urethane-modified vinyl polymer Using 3.8 g of dimethylethanolamine and 175 g of water, an ethyl acetate solution of the urethane-modified vinyl polymer (F) obtained in section (iii) above was prepared. In the same manner as described in Section (iv) of Example 1, an aqueous dispersion of a urethane-modified vinyl polymer (PH
8.5).

The stability of the obtained aqueous dispersion of the urethane-modified vinyl polymer was very good, and the film obtained by coating and drying this dispersion on a glass plate had excellent water resistance and weather resistance. It was hot.

Example 3 (i) Production of vinyl polymer having hydroxyl group and carboxyl group The ethyl acetate solution of the vinyl polymer (D) in item (i) of Example 2 is used.

(ii) Cutting of urethane prepolymer having terminal isocyanate groups 100 g of ethyl acetate, polyester glycol (esterified in a molar ratio of adipic acid: phthalic anhydride: 1,4-butanediol = 1:1:3) Using 66.5 g, TDI 34 g, ethanol 3 g, and dibutyltin dilaurate 0.06 g, the same operation as in section (ii) of Example 1 was performed to obtain a urethane prepolymer having terminal isocyanate groups.
An ethyl acetate solution of (G) was obtained. The reaction component ratio of this urethane prepolymer (G) is polyester glycol:TDI:ethanol=2:3:1 (molar ratio), and it has one terminal isocyanate group on average.

(iii) Production of urethane-modified vinyl polymer Ethyl acetate solution of vinyl polymer (D) in item (i) above
64.5g, 82g of the ethyl acetate solution of the urethane prepolymer (G) from item (ii) above, and 4.8g of ethanol.
Using g, the same operation as in section (iii) of Example 1 was performed to obtain an ethyl acetate solution of the urethane-modified vinyl polymer (H). The reaction ratio of urethane prepolymer/vinyl polymer in this reaction is approximately 6/5 by weight, and approximately 1/2.2 by equivalent ratio of NCO/OH.
The obtained urethane-modified vinyl polymer (H)
The acid value was approximately 37.

(iv) Preparation of aqueous dispersion solution of urethane-modified vinyl polymer Using 5.0 g of dimethylethanolamine and 170 g of water, an ethyl acetate solution of the urethane-modified vinyl polymer (H) obtained in the above (iii) was prepared. In the same manner as described in Section (iv) of Example 1, an aqueous dispersion of a urethane-modified vinyl polymer (PH
8.3) was obtained.

The stability of the obtained aqueous dispersion of the urethane-modified vinyl polymer was very good, and the dry film obtained by coating this dispersion on a glass plate was
It was colorless and transparent, and had excellent water resistance and weather resistance.

Example 4 (i) Production of a vinyl polymer having a hydroxyl group and a carboxyl group In the operation in item (i) of Example 1, 280 g of ethyl acetate was used as a solvent, and 50 g of acrylic acid, 2-hydroxy as a mixed monomer. ethyl acrylate
40g, 2-ethylhexyl acrylate 20g,
Methyl methacrylate 90g, thioglycolic acid 2
g, azobisisobutyronitrile, 4 g, except that a mixed monomer solution consisting of 4 g of azobisisobutyronitrile was used.
The same procedure as in section (i) was carried out to obtain 476 g of an ethyl acetate solution of vinyl polymer (I).

This vinyl polymer (I) has an acid value of 195 and a hydroxyl value of 94.

(ii) Production of urethane prepolymer having terminal isocyanate groups 100 g of ethyl acetate, 46.6 g of polyethylene glycol (molecular weight 200), 50.7 g of TDI, 2.7 g of ethanol
The same operation as in section (ii) of Example 1 was carried out using 0.06 g of dibutyltin dilaurate to obtain an ethyl acetate solution of the urethane prepolymer (J) having terminal isocyanate groups.

The reaction component ratio of this urethane prepolymer (J) is
Polyethylene glycol: TDI: Ethanol =
The molar ratio is 4:5:1, and the average is one terminal isocyanate group.

(iii) Production of urethane-modified vinyl polymer Ethyl acetate solution of vinyl polymer (I) in item (i) above
87g and the same urethane prepolymer described in item (ii) above.
Using 75 g of an ethyl acetate solution of (J) and 4 g of ethanol, the same operation as in section (iii) of Example 1 was performed to obtain an ethyl acetate solution of the urethane-modified vinyl polymer (K). The reaction ratio of urethane prepolymer/vinyl polymer in this reaction was approximately 1/1 in weight ratio and approximately 1/2.87 in equivalent ratio of NCO/OH, and the resulting urethane modified vinyl polymer ( The acid value of K) was approximately 98.

(iv) Preparation of an aqueous dispersion solution of urethane-modified vinyl polymer Using 14 g of dimethylethanolamine and 285 g of water, prepare an ethyl acetate solution of the urethane-modified vinyl polymer (K) obtained in section (iii) above. An aqueous dispersion of urethane-modified vinyl polymer with a polymer concentration of 25% (PH
6.9) was obtained.

The stability of the obtained aqueous dispersion of the urethane-modified vinyl polymer was very good, and the film obtained by coating and drying this dispersion on a glass plate had excellent water resistance and weather resistance. It was colorless and transparent.

Comparative Example 1 (i) Production of a vinyl polymer having a hydroxyl group and a carboxyl group Among the operations in section (i) of Example 1, 10 g of acrylic acid, 30 g of 2-hydroxyethyl acrylate, and 2-ethylhexyl were used as mixed monomers. The same procedure as in (i) of Example 1 was carried out except for using a mixed monomer solution consisting of 30 g of acrylate, 130 g of methyl methacrylate, 2 g of thioglycolic acid, and 4 g of azobisisobutyronitrile. 390 g of an ethyl acetate solution of ) was obtained.

The acid value of this vinyl polymer (L) was 43.

(ii) Production of urethane prepolymer having terminal isocyanate groups Urethane prepolymer in section (ii) of Example 4
Use an ethyl acetate solution of (J).

(iii) Production of urethane-modified vinyl polymer 47 g of an ethyl acetate solution of the vinyl polymer (L) obtained in section (i) above and the urethane having terminal isocyanate groups also obtained in section (ii) above. prepolymer
Using 100 g of an ethyl acetate solution of (J) and a small amount of ethanol, the same operation as in section (iii) of Example 1 was performed to obtain an ethyl acetate solution of the urethane-modified vinyl polymer (M).

The reaction ratio of urethane prepolymer/vinyl polymer in this reaction is approximately 2/1 by weight,
The equivalent ratio of NCO/OH was about 1/1.08, and the acid value of the obtained urethane-modified vinyl polymer (M) was about 15.

(iv) Preparation of aqueous dispersion solution of urethane-modified vinyl polymer Using 2.3 g of dimethylethanolamine and 172 g of water, an ethyl acetate solution of the urethane-modified vinyl polymer (M) obtained in the above (iii) was prepared. Proceed in the same manner as described in section (iv) of Example 1, with a polymer concentration of 30%.
An aqueous dispersion solution (PH8.1) of a urethane-modified vinyl polymer was obtained.

After leaving the obtained aqueous dispersion of the urethane-modified vinyl polymer for 24 hours, we observed its stability. As a result, a large amount of precipitated substances were generated in the dispersion, and its stability was poor. There was found.
Further, the film obtained by applying this dispersion solution onto a glass plate and drying it was cloudy.

Claims (1)

[Claims] 1. An acid value of 20 obtained by reacting a vinyl polymer having a hydroxyl group and a carboxyl group with a urethane prepolymer having a terminal isocyanate group.
An aqueous dispersion solution of a urethane-modified vinyl polymer, characterized in that the above-mentioned urethane-modified vinyl polymer is dispersed in an aqueous solvent containing an alkaline substance. 2. The aqueous urethane-modified vinyl polymer according to claim 1, wherein the vinyl polymer having a hydroxyl group and a carboxyl group is an acrylic polymer having a hydroxyl value of 30 to 200 and an acid value of 30 to 250. Dispersion solution. 3. The aqueous urethane-modified vinyl polymer according to claim 1 or 2, wherein the urethane prepolymer having terminal isocyanate groups is a urethane prepolymer having an average of 1 to 1.5 terminal isocyanate groups per molecule. Dispersion solution. 4. A urethane-modified vinyl polymer obtained by reacting a vinyl polymer having a hydroxyl group and a carboxyl group with a urethane prepolymer having a terminal isocyanate group is a urethane-modified vinyl polymer having an acid value of 200 or less. An aqueous dispersion solution of a urethane-modified vinyl polymer according to claim 1, 2, or 3. 5 A vinyl polymer having a hydroxyl group and a carboxyl group and a urethane prepolymer having a terminal isocyanate group have a dissolving effect on both the vinyl polymer and the urethane prepolymer, but the The acid value of
An aqueous dispersion solution of a urethane-modified vinyl polymer, characterized in that 20 or more urethane-modified vinyl polymers are produced, and then the obtained urethane-modified vinyl polymer is dispersed in an aqueous solvent containing an alkaline substance. manufacturing method. 6. The aqueous urethane-modified vinyl polymer according to claim 5, wherein the vinyl polymer having a hydroxyl group and a carboxyl group is a vinyl polymer having a hydroxyl value of 30 to 200 and an acid value of 30 to 250. Method for producing a dispersion solution. 7. The aqueous urethane-modified vinyl polymer according to claim 5 or 6, wherein the urethane prepolymer having terminal isocyanate groups is a urethane prepolymer having an average of 1 to 1.5 terminal isocyanate groups per molecule. Method for producing a dispersion solution. 8 When heating a vinyl polymer having a hydroxyl group and a carboxyl group and a urethane prepolymer having a terminal isocyanate group in an organic solvent, hydroxyl groups 1 to 5 in the vinyl polymer are heated.
Claims 5, 6, or 7 consisting of reacting at a reaction ratio of 1 equivalent of terminal isocyanate groups in the urethane prepolymer to 1 equivalent of terminal isocyanate groups in the urethane prepolymer.
A method for producing an aqueous dispersion of a urethane-modified vinyl polymer as described in 1. 9. The aqueous dispersion of a urethane-modified vinyl polymer according to claim 5, 6, 7, or 8, wherein the alkaline substance in the aqueous solvent containing an alkaline substance is ammonia, a volatile organic amine, or a mixture thereof. Method of manufacturing the solution.