JPH09202802A - Production of nonaqueous polymer dispersion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new method for producing a nonaqueous polymer dispersion having a dispersoid with small average particle diameter, capable of using as a rheology controlling agent having excellent sagging-preventing effect to solve the problem of appearance of a coated film. SOLUTION: This method for producing a nonaqueous polymer dispersion comprises carrying out solution polymerization of a vinyl monomer in an organic solvent capable of dissolving a disperse stabilizer without dissolving the vinyl polymer constituting a dispersoid of a nonaqueous polymer dispersion, while using an addition reaction product of a linear polyester having a carboxyl group at one end with a glycidyl group-containing acrylic resin as the disperse stabilizer. In the method, the polymerization is carried out by dropping the vinyl monomer into a disperse stabilizer solution containing 0.001-0.5wt.% radical polymerization initiator based on the vinyl monomer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a non-aqueous polymer dispersion used as a rheology control agent for paints, and more specifically, a non-aqueous system having an excellent anti-sagging effect with a smaller addition amount than before. It relates to a method for producing a polymer dispersion.

[0002]

2. Description of the Related Art In recent years, there has been an increasing need for paints having excellent coating film appearance, and many paint manufacturers have developed and marketed many paints. In order for a paint to have a high coating appearance, it is necessary to impart a sagging preventive effect to the paint to make the coating smooth. Aluminum powder,
For a coating material containing a glitter material typified by a pearl pigment, it is also necessary to orient the glitter material in parallel with the object to be coated. For these purposes, a viscosity controlling agent called a rheology control agent such as an amide wax having an anti-sagging effect, an organic bentonite, a reactive microgel and a non-aqueous polymer dispersion is used. Among these rheology control agents, reactive microgels and non-aqueous polymer dispersions have been attracting much attention in recent years because their compositions can be freely changed. Although the reactive microgel and the non-aqueous polymer dispersion liquid are dispersed as a particulate resin in the coating material, they are aggregated to give viscosity to the coating material when it becomes a coating film after coating. As a result, the flow (drip) on the surface of the coating film, the flow of the glittering material, etc. are suppressed, and the appearance of the coating film is improved. Therefore, the effect of improving the coating appearance of the reactive microgel and the non-aqueous polymer dispersion depends on the cohesive force of the particles, but the strength of the cohesive force depends on the polarity of the particles and the size of the particles. Depending on the size of the determined surface area, the smaller the particles, the larger the surface area of the particles, which leads to the effect of improving the anti-sagging effect.

Reactive microgels are obtained by emulsion polymerization of vinyl monomers and have an average particle size of 50-100.
nm, which is an advantage of having a small particle size among other rheology control agents. However, after the production, it is necessary to perform a phase conversion step of moving the particles of the reactive microgel to the organic solvent layer, and it is necessary to perform a treatment for removing the emulsifier used, and the remaining emulsifier makes the water resistance of the coating material. It has the drawback of blocking. On the other hand, the non-aqueous polymer dispersion,
An acrylic resin graft-bonded with a polyester polymer or a 12-hydroxystearic acid self-condensate is used as a dispersion stabilizer, and the dispersion stabilizer is dissolved without dissolving the vinyl polymer constituting the particle component of the non-aqueous polymer dispersion. It is obtained by dropping a vinyl monomer composition and a polymerization initiator into a dispersion stabilizer solution using a solvent and carrying out solution polymerization (Japanese Patent Laid-Open No. 64-54074). The advantages of such a non-aqueous polymer dispersion include that a phase inversion step and a step of removing an emulsifier in the reactive microgel are unnecessary, and that the lack of stability due to the remaining emulsifier is not considered. . However, the average particle size of the obtained particles is 300-
This is 600 nm, which is larger than that of the reactive microgel, and there is a drawback that the effect of suppressing the flow (sagging) on the surface of the coating film and the flow of the glittering material is small due to the size of the average particle size.
As described above, if a non-aqueous polymer dispersion having a small average particle size can be synthesized, a rheology control agent that compensates for the disadvantages of the reactive microgel and the non-aqueous polymer dispersion can be obtained. As expected, no such non-aqueous polymer dispersion has been found.

[0004]

The present invention is a non-aqueous polymer having a dispersoid with a small average particle diameter, which can be used as a rheology control agent having an excellent anti-sagging effect for solving the problem of coating film appearance. The present invention provides a novel method for producing a dispersion liquid.

[0005]

Means for Solving the Problems As a result of earnest research by the present inventors, the conventional production method in which a mixture of a vinyl monomer and a radical polymerization initiator was dropped into an organic solvent in which a dispersion stabilizer was dissolved to carry out polymerization Instead of the method, a vinyl monomer is dropped into an organic solvent in which a radical polymerization initiator and a dispersion stabilizer are dissolved and polymerized to produce a non-aqueous polymer dispersion having a dispersoid with a small average particle size. The present inventors have completed the present invention by finding that this non-aqueous polymer dispersion can be used as a rheology control agent for solving the problem of coating film appearance. That is, the present invention, the addition reaction product of a linear polyester having a carboxyl group at one end and a glycidyl group-containing acrylic resin as a dispersion stabilizer, to dissolve the vinyl polymer constituting the dispersoid of the non-aqueous polymer dispersion In the method of obtaining a non-aqueous polymer dispersion by solution-polymerizing a vinyl monomer in an organic solvent that dissolves a dispersion stabilizer without using a radical polymerization initiator, 0.001 to 0.5% by weight based on the vinyl monomer. %, A vinyl monomer is added dropwise to the dispersion stabilizer solution to be polymerized, and the resulting dispersion is polymerized.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The method for producing a non-aqueous polymer dispersion of the present invention relates to a method for reducing the average particle size of dispersoids in a non-aqueous polymer dispersion, in which a vinyl monomer is used as a dispersion stabilizer. Before being added dropwise to the solution, a radical polymerization initiator is added to the dispersion stabilizer solution in an amount of 0.001 to 0.5% by weight, preferably 0.01 to 0.5% by weight, based on the vinyl monomer.
0.3 wt% is added, and then a vinyl monomer is dropped into the dispersion stabilizer solution to polymerize. In this case, the radical polymerization initiator may be contained in the dropped vinyl monomer. Further, in this case, if the radical polymerization initiator is not contained in the dispersion stabilizer solution but is contained only in the vinyl monomer to be dropped, a non-aqueous polymer dispersion having a target dispersoid with a small average particle size is obtained. No liquid is obtained. The addition amount of the radical polymerization initiator is 0.00 with respect to the total amount of the vinyl monomer.
If it is less than 1% by weight, the average particle size of the obtained non-aqueous polymer dispersion is not much different from that by the conventional method, and is 0.5.
Even if it exceeds the weight%, the average particle size does not become so small.

Further, as a dispersion stabilizer when a non-aqueous polymer dispersion is produced using the production method of the present invention, an addition reaction of a linear polyester having a carboxyl group at one end and an acrylic resin containing a glycidyl group is produced. You have to use things. Here, a linear polyester having a carboxyl group at one end contains only one carboxyl group as a functional group capable of reacting with a glycidyl group in one molecule, and the position where it is present is the end of the molecule. Is. A particularly preferable linear polyester polymer having a carboxyl group at one end is a linear polyester obtained by reacting an intramolecular acid anhydride, a monocarboxylic acid and a monoglycidyl compound, or 12-hydroxystearin. It is a linear polyester that is a self-condensation product of an acid.

Here, as the intramolecular acid anhydride, compounds having an acid anhydride group such as phthalic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, maleic anhydride, dodecyl succinic anhydride can be used. Hexanoic acid, heptanoic acid, 2-ethylhexanoic acid, lauric acid, stearic acid, oleic acid, linoleic acid and the like can be used as the monocarboxylic acid. Further, as a monoglycidyl compound, phenylglycidyl ether,
A compound having one glycidyl group such as p-tolyl glycidyl ether, n-butyl glycidyl ether, persatic acid glycidyl ester, p-tert-butyl benzoic acid glycidyl ester can be used. A linear polyester polymer having a carboxyl group at one end can be obtained by a known method using these compounds. That is, a monohydroxyl compound is first produced by the reaction of a monocarboxylic acid and a monoepoxy compound, and the reaction conditions and the molar ratio of the raw materials are sequentially adjusted so that the acid anhydride and the epoxy compound are sequentially reacted. A linear polyester polymer having a carboxyl group can be obtained.

A self-condensate of oxycarboxylic acid can also be used as the linear polyester polymer having a carboxyl group at one end, and a self-condensate of 12-hydroxystearic acid is particularly preferable. As a method for self-condensing an oxycarboxylic acid, for example, an oxycarboxylic acid may be heated to form an intermolecular esterified product.

A glycidyl group-containing acrylic resin which undergoes an addition reaction with a linear polyester having a carboxyl group at one end is an acrylic resin containing a glycidyl group in the molecule, and for example, glycidyl (meth) acrylate (hereinafter referred to as acrylic and meta Acrylic together (meth) acrylic, allyl and methallyl together ((meth) allyl), polymerizable vinyl groups such as β-methylglycidyl (meth) acrylate, (meth) allylglycidyl ether and glycidyl groups A monomer having both and methyl (meth) acrylate,
Ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate,
T-butyl (meth) acrylate, n (meth) acrylate
-Hexyl, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, (meth)
(Meth) acrylic acid ester such as 2-hydroxyethyl acrylate and 2-hydroxypropyl (meth) acrylate, (meth) acrylamide, n-hydroxymethyl (meth) acrylamide, (meth) acrylonitrile,
Copolymer with a monomer having a polymerizable vinyl group such as (meth) acrylamide, n-hydroxymethyl (meth) acrylamide, (meth) acrylonitrile, vinyl acetate, styrene, vinyltoluene, vinylpyrrolidone, and (meth) allyl alcohol. Is.

The reaction between a linear polyester having a carboxyl group at one end and an acrylic resin containing a glycidyl group is
It can be easily carried out by reacting the carboxyl group in the polyester with the glycidyl group in the acrylic resin as it is or by heating in an organic solvent. Further, there is no problem in using a catalytic amount of an amine compound, a quaternary ammonium salt, a phosphonium salt, a Lewis acid salt or the like in order to accelerate the reaction.

Examples of the organic solvent which does not dissolve the vinyl polymer constituting the dispersoid of the non-aqueous polymer dispersion and dissolves the dispersion stabilizer include, for example, n-hexane and cyclohexane.
Aliphatic hydrocarbons such as methylcyclohexane, ethylcyclohexane, n-heptane, n-octane and mineral spirits; aromatic hydrocarbons such as benzene, toluene, xylene and ethylbenzene; methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, butyl Alcohol, alcohol such as isobutyl alcohol; ester such as methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, isobutyl acetate, cellosolve acetate; acetone, methyl ethyl ketone,
Examples thereof include ketones such as methyl isobutyl ketone, methyl amyl ketone, cyclohexanone, and isophorone.
From these, a solvent that dissolves the dispersion stabilizer and does not dissolve the polymer that becomes the dispersoid of the non-aqueous polymer dispersion is selected. Further, as the organic solvent, a mixed organic solvent of two or more kinds can be used, and the mixed organic solvent has a property of dissolving the dispersion stabilizer without dissolving the vinyl polymer constituting the dispersoid of the non-aqueous polymer dispersion. It should be equipped.

As the vinyl monomer used in the production of the vinyl polymer which is the dispersoid of the non-aqueous polymer dispersion of the present invention, the monomers used in the production of ordinary paint resins can be used. For example, (meth) Methyl acrylate,
Ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate,
T-butyl (meth) acrylate, n (meth) acrylate
-Hexyl, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, (meth)
Glycidyl acrylate, 2-hydroxyethyl (meth) acrylate, (meth) acrylic acid ester such as 2-hydroxypropyl (meth) acrylate, (meth) acrylic acid, (meth) acrylamide, N-hydroxymethyl (meth) Acrylamide, (meth) acrylonitrile,
One or more compounds having a polymerizable double bond such as vinyl acetate, styrene, vinyltoluene, vinylpyrrolidone, (meth) allylglycidyl ether, and (meth) allyl alcohol can be used. A non-aqueous polymer dispersion can be produced by polymerizing these monomers according to the method described above.

The radical polymerization initiator used in the present invention includes 2,2'-azobisisobutyronitrile and 2,2 '.
-Azobis (2,4-dimethylvaleronitrile), 1-
Azo-based polymerization initiators such as azobis-1-cyclohexanecarbonitrile and dimethyl-2,2′-azobisisobutyrate; benzoyl peroxide, lauroyl peroxide, bis-3,5,5-trimethylhexyl peroxide, t- Butyl cumyl peroxide, di-t-butyl peroxide, 1,1-di-t-butyl peroxy-
3,3,5-Trimethylcyclohexane, t-butylperoxy-2-ethylhexanoate, t-butylperoxybenzoate, cumene hydroperoxide, t-
Peroxide-based polymerization initiators such as butyl hydroperoxide and dimethoxybutyl peroxydicarbonate are preferred, and one or more of these can be selected depending on the reaction temperature in the production of the non-aqueous polymer dispersion. The amount of these polymerization initiators used is 0.001 to 0.5% by weight based on the vinyl monomer constituting the dispersoid.

Further, the weight ratio of the dispersion stabilizer used in the method for producing the non-aqueous polymer dispersion of the present invention to the total amount of the vinyl monomer as the raw material of the vinyl polymer of the dispersoid is 1:
It is 1 to 1:10, preferably 1: 2 to 1: 5. 1:
When it is less than 1, the rheological effect of the obtained non-aqueous polymer dispersion is insufficient, and when it exceeds 1:10, the dispersion stability of the non-aqueous polymer dispersion is lowered. The size of the dispersoid particles of the non-aqueous polymer dispersion obtained in the present invention is about 1.
It is 00-200 nm.

The non-aqueous polymer dispersion obtained by the method of the present invention is used as a rheology control agent for paints,
An excellent anti-sagging effect can be given. The amount of the non-aqueous polymer dispersion added to the coating material is 0.5 to 20% by weight, and more preferably 2 to 10% by weight, based on the resin solid content in the coating material.

[0017]

By the method for producing a non-aqueous polymer dispersion of the present invention, the average particle size of the non-aqueous polymer dispersion becomes smaller than the average particle size of the non-aqueous polymer dispersion obtained by the conventional method. It can be applied to paints as a rheology control agent having an excellent anti-sagging effect.

[0018]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples. Production Examples 1 to 4 (Production of Polyester Having Carboxyl Group at One Terminal) The mixture shown in Table 1 was charged in a four-necked flask equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen gas introducing tube, while blowing nitrogen gas. The reaction was continued under reflux, and when the acid value of the reaction solution reached the theoretical value, the reaction was stopped to obtain a polyester resin having a carboxyl group at one end used for producing the dispersion stabilizer. Here, the theoretical value of the acid value is as shown in Table 1.

[0019]

[Table 1]

Note in Table 1 * 1: Versatic acid glycidyl ester, glycidyl tertiary carboxylate glycidyl produced by Yuka Shell Epoxy Co., Ltd., epoxy equivalent 250 * 2: Measurement of acid value; JIS-K-5407 (1990)
by.

Production Examples 5 to 8 (Production of Glycidyl Group-Containing Acrylic Resin) Into a four-necked flask equipped with a stirrer, a thermometer, a reflux condenser and a dropping funnel was added toluene as shown in Table 2.
0% by weight and 35.2% by weight of xylene were charged, and the temperature was raised to reflux with stirring. Then, the mixture of the dropping components shown in Table 2 was dropped from the dropping funnel at a constant addition rate over 2 hours. Thirty minutes after the completion of dropping, an additional catalyst was added and the mixture was kept under reflux for 2 hours to obtain a glycidyl group-containing acrylic resin used for producing a dispersion stabilizer.

[0022]

[Table 2]

Production Examples 9 to 24 (Production of Dispersion Stabilizer) A four-necked flask equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen gas inlet tube was charged with carboxyl at one end obtained in Production Examples 1 to 4 above. Group-containing polyester resins PE1-P
E4 and the glycidyl group-containing acrylic resins PA1 to PA4 obtained in Production Examples 5 to 8 were added in the formulations shown in Tables 3 and 4. The reaction mixture was heated to reflux with stirring, and when the acid value became 1 or less, the reaction was stopped and the dispersion stabilizer D
1 to D16 were obtained.

[0024]

[Table 3]

[0025]

[Table 4]

Examples 1 to 18 (Production of Non-Aqueous Polymer Dispersion) Using the dispersion stabilizers produced in Production Examples, non-aqueous polymer dispersions were synthesized according to the formulations shown in Tables 5 and 6. That is, 4 equipped with a stirrer, thermometer, reflux condenser and dropping funnel.
16. Add the dispersion stabilizer prepared in the above Preparation Example to the neck flask.
0% by weight was added and the temperature was raised to 95 to 100 ° C with stirring. Then, a polymerization initiator was added to Examples 1 to 7 and Examples 10 to 1.
In the case of No. 8, 0.153% by weight (% by weight based on vinyl monomer, the same applies hereinafter), 0.076% by weight in Example 8 and 0.031% by weight in Example 9 were added. The dropping composition shown was dropped from the dropping funnel at a constant rate over 3 hours. An additional catalyst was added 30 minutes after the dropwise addition was completed, and the temperature was raised to 120 ° C. 30 minutes after the addition, and the temperature was maintained for 2 hours to obtain a milky white non-aqueous polymer dispersion liquid (N1 to N18). The average particle size of the dispersoids of the obtained non-aqueous polymer dispersion liquids N1 to N18 and the anti-sagging effect in the clear paint were measured by the methods described below. The measurement results of the average particle size are also shown in Table 5 and Table 6.
Tables 8 and 9 show the results of evaluation of the clear coating composition and anti-sagging effect.

Comparative Example 1 (Production of Non-Aqueous Polymer Dispersion Liquids Other Than the Present Invention) When no polymerization initiator was added to the dispersion stabilizer solution in advance, the non-aqueous polymer dispersion liquid ( HN1) was produced. Table 7 shows the compounding composition at the time of production. The average particle diameter of the dispersoid and the anti-sagging effect of the obtained non-aqueous polymer dispersion were measured in the same manner as in the examples. Table 7 shows the measurement results of the average particle size, and Table 9 shows the formulation of the coating used for the evaluation of the anti-sagging effect and the evaluation results.

Reference Example 1 (Production of Acrylic Resin for Paint Used in the Test of the Present Invention) An acrylic resin used in the test of the present invention was produced by the following method. That is, xylene 3 was placed in a 4-neck flask equipped with a stirrer, a thermometer, a reflux condenser and a dropping funnel.
9.0 parts by weight was charged, and the temperature was raised to reflux with stirring. Then, as a dropping component, 6.9 parts by weight of 2-hydroxyethyl methacrylate, 21.9 parts by weight of butyl acrylate, 30.3 parts by weight of styrene, 0.7 part by weight of acrylic acid and t-butylperoxy-2-ethylhexa. A mixture of 1.2 parts by weight of Noate was added dropwise from the dropping funnel at a constant addition rate over 2 hours. After the completion of dropping, the mixture was kept under reflux for 2 hours to obtain an acrylic resin for paint used in the test. The resulting acrylic resin has a nonvolatile content of 60.6% by weight.
(Theoretical value 61.0% by weight).

[0029]

[Table 5]

Note 5 in Table 5: The value in () is the weight% of the radical initiator in the dispersion stabilizer solution with respect to the vinyl monomer.

[0031]

[Table 6]

Note * 1 in Table 6: () indicates the weight% of the radical initiator in the dispersion stabilizer solution with respect to the vinyl monomer.

[0033]

[Table 7]

[0034]

[Table 8]

[0035]

[Table 9]

Note in Tables 8 and 9 * 1: Acrylic resin produced in Reference Example 1. * 2: n-butylated melamine resin (resin solid content 60
%): Mitsui Toatsu Chemical Co., Ltd. product name * 3: UV absorber (10% xylene solution): Ciba Geigy product name * 4: Hindered amine light stabilizer: Ciba Geigy product name

Test Method The average particle size in Examples and Comparative Examples was measured by NICO.
MP Model 370 (Particle Siz
e Systems, trade name) was used for measurement by the laser light scattering method. The sagging prevention effect was evaluated by the following method. That is, a zinc phosphate-treated steel sheet was coated with a cationic electrodeposition coating (trade name: Aqua No. 4200, manufactured by NOF CORPORATION) to a dry film thickness of 20 μm, and baked at 175 ° C. for 25 minutes for electrodeposition. A coated board was obtained.
In addition to this, an intermediate coating (trade name High Epico No. 1500C
P sealer, manufactured by NOF CORPORATION, with a dry coating thickness of 40μ
After air-spraying so as to have m, it was baked at 140 ° C. for 30 minutes to prepare a test plate. To this, paints prepared with the formulations of Tables 8 and 9 were applied with thinner (Solveso # 100 / xylene / n-butyl alcohol = 4/4 /
2 weight ratio, coating viscosity (Ford Cup No. 4, 2
The test plate was diluted with 0 ° C. for 25 seconds) by air spray coating and baked at a temperature of 140 ° C. for 30 minutes while standing vertically to measure the maximum film thickness without sagging. The measurement results are also shown in Tables 8 and 9. From the measurement results of Tables 5 to 9, the non-aqueous polymer dispersions obtained in Examples 1 to 18 have much smaller average particle diameters than those obtained in Comparative Examples, and also have an excellent anti-sagging effect. You can see that

Claims (4)

[Claims] 1. A vinyl polymer constituting a dispersoid of a non-aqueous polymer dispersion is dissolved by using an addition reaction product of a linear polyester having a carboxyl group at one end and a glycidyl group-containing acrylic resin as a dispersion stabilizer. In a method of obtaining a non-aqueous polymer dispersion by solution-polymerizing a vinyl monomer in an organic solvent which dissolves a dispersion stabilizer without adding a radical polymerization initiator, the radical polymerization initiator is added in an amount of 0.001 to 0.5 with respect to the vinyl monomer.
A method for producing a non-aqueous polymer dispersion, which comprises adding a vinyl monomer dropwise to a dispersion stabilizer solution containing 1% by weight to perform polymerization. 2. The method for producing a non-aqueous polymer dispersion according to claim 1, wherein the weight ratio of the dispersion stabilizer and the vinyl monomer is 1: 1 to 1:10. 3. The non-aqueous polymer dispersion according to claim 1, wherein the linear polyester having a carboxyl group at one end is a polyester obtained by polymerizing an intramolecular acid anhydride, a monocarboxylic acid compound and a monoepoxy compound. Manufacturing method. 4. The method for producing a non-aqueous polymer dispersion according to claim 1, wherein the linear polyester having a carboxyl group at one end is a self-condensation product of 12-hydroxystearic acid.