JPH0834953A - Water-based titanium paste having high pigment content - Google Patents

Abstract

PURPOSE:To obtain the paste excellent in dispersibility of pigment without loosing fluidity even if surface-treated titanium dioxide having ultrahigh weather ing resistance is contained in a high content by using a neutralized material obtained by neutralizing a styrene-maleic anhydride copolymer resin having a specific ratio of styrene with maleic anhydride with a basic compound. CONSTITUTION:This paste is obtained by blending (A) 100 pts.wt. of surface- treated titanium dioxide pigment with (B) 0.5-19 pts.wt. (as a solid content) of a styrene-maleic anhydride copolymer resin, partially esterified and neutralized with a basic compound, having about 5000-15000 molecular weight and obtained by copolymerizing styrene with maleic anhydride in a weight ratio of (1-1.5):1, so that a ratio of pigment solid content to the total amount may be 60-75wt.%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aqueous titanium paste used in the production of an aqueous paint, which has a high content of a surface-treated titanium dioxide pigment having high weather resistance, and a molecular weight of a resin in which titanium dioxide is dispersed. It has a good fluidity despite its relatively high value.

[0002]

2. Description of the Related Art Conventionally, titanium dioxide has been used as a coloring pigment in the production of water-based paints. In an aqueous paint using an emulsion or a water-soluble resin, a pigment-dispersed paste having good compatibility with the binder is produced and blended in order to favorably disperse titanium dioxide in these binders. Such a pigment-dispersed paste has a molecular weight of about 500 to 5,000 and a styrene / maleic acid ratio of 0.2 to 4/1 as disclosed in JP-B-54-10019 as a water-based processed pigment. For example, a basic compound salt of a styrene-maleic anhydride copolymer resin ester and a nonionic surfactant having an HLB of 9 to 20 are dispersed together with a pigment in water.

[0003]

Since the above water-based processed pigment does not use a large amount of a surfactant as in the pigment dispersion paste before that, the weather resistance of the coating film using this is improved. However, the demand for weather resistance of the coating film is further increasing under the present circumstances, and various attempts have been made to cope with such a present condition. The first of such attempts is to use a resin having a relatively high molecular weight for dispersing titanium dioxide.
This is 500 to 50 of the dispersion resin of the above water-based processed pigment.
This is because with a molecular weight of 00, a coating film formed from a water-based paint containing this compound is insufficient in various physical properties of the coating film including water resistance. The second is to use ultra-weather resistant grades made by subjecting titanium dioxide to various surface treatments. This is because titanium dioxide is originally excellent in the ability to block ultraviolet rays, but the pigment surface in the coating film is reduced by ultraviolet rays to generate atomic oxygen, which oxidizes the synthetic resin of the binder, which is the main element for forming the coating film. ,
This is to prevent this by surface treatment. However,
Ultra-weather resistant grade titanium dioxide that has undergone such a surface treatment generally has poor dispersibility in water, and in combination with the use of a resin with a relatively high molecular weight for dispersing titanium dioxide, titanium paste Liquidity of the. This decrease in fluidity has been a problem in that it is clogged in a raw material supply pipe in a paint manufacturing factory and lacks in smoothness when the titanium paste is put into a paint agitation tank and it takes time. For this reason, the content of titanium dioxide pigment in the paste must be reduced to ensure fluidity, and as a result, a large amount of titanium paste must be blended in order to obtain the same hiding power in the paint production. The degree of freedom in designing the composition was reduced. In addition, even when transporting the titanium paste itself, the weight of the same titanium dioxide is higher than that of a high content,
As a result, the volume increases and the transportation cost increases. Thus, in the aqueous titanium paste, there is a conflict that the content of the pigment is high, the titanium dioxide has super weatherability, the resin for dispersing the pigment has a relatively high molecular weight, and yet has high fluidity. I couldn't find anything that could fulfill the task. The problem to be solved by the present invention is to obtain such an aqueous titanium paste.

[0004]

In order to solve such a problem, the inventors of the present invention have made earnest studies, and as a result, as a result, styrene-maleic anhydride copolymer resin having a relatively high molecular weight of about 5000 to 15000. By setting the ratio of styrene / maleic anhydride in the neutralized basic compound to a specific range, the fluidity is not lost even when the content of super weathering surface-treated titanium dioxide is high, and the pigment dispersibility is maintained. We solved the problem by finding that it is excellent. That is, 100 parts by weight of the surface-treated titanium dioxide pigment was copolymerized with styrene / maleic anhydride at a weight ratio of 1 to 1.5 / 1, and had a molecular weight of about 5,000 to 15,000 and was partially esterified. Further, 0.5 to 19 parts by weight of the styrene-maleic anhydride copolymer resin neutralized with a basic compound is mixed in the solid content, and the ratio of the pigment solid content to the whole aqueous titanium paste is 60 to 75% by weight. To do so. Here, the super weather resistant surface-treated titanium dioxide pigment corresponds to a super weather resistant grade of a normal titanium dioxide pigment, and for example, "titanium oxide-physical properties and applied technology" (199).
June 25, 1st, Gihodo Publishing Co., Ltd. Issue 37-3
Some of the main applications are paints with super weather resistance as described in Table 3.3 "Classification of titanium oxide products for pigments" on page 9). CR-97, CR-90, CR-93 manufactured by Ishihara Sangyo Co., Ltd. , CR
-95, JR-603, JR-80 manufactured by Teika Co., Ltd.
5, Sakai Chemical R-61N, R-52N, R-62N, Furukawa Kikinzoku FR-35, D-Pont R-960, T
Ioxide R-TC60, R-TCY, R-CR
60 and the like. Next, the styrene-maleic anhydride copolymer resin has a molecular weight of about 5,000 to 15,000, but when the molecular weight is less than 5,000, the weather resistance of the coating material produced using the aqueous titanium paste of the present invention decreases, As a result, there arises a problem that the gloss retention rate of the coating film decreases quickly. On the other hand, when the molecular weight is more than 15,000, the fluidity is lowered and the titanium dioxide is not sufficiently dispersed, so that the hiding property is lowered. When the weight ratio of styrene / maleic acid in the molecule is smaller than 1/1 or larger than 1.5 / 1, it has a structural viscosity, and the viscosity increases with time during long-term storage, resulting in fluidity. descend. The styrene-maleic anhydride copolymer resin is partially esterified and neutralized with a basic compound, but the partial esterification can be carried out within a range not impairing the water dilutability of the copolymer. A particularly desirable range of partial esterification is a degree of esterification of 30 to 70%. As the esterification agent, usable are n-amyl alcohol, isoamyl alcohol, secondary amyl alcohol, tertiary amyl alcohol, n-butanol, secondary butanol, tertiary butanol, isobutanol, methanol, ethanol, n- Propanol, isopropanol, third
Pentanol, 2-ethylbutanol, butyl cellosolve, ethyl cellosolve, phenyl cellosolve, carbitol, butyl carbitol, tetrahydrofurfuryl alcohol, n-hexanol, tertiary pentanol, butoxyethoxypropanol, 2 ethylhexanol, cyclohexanol, etc. . Further, the basic compound for partially neutralizing is, for example, ammonia, primary amine,
There are secondary amines, tertiary amines, and hydroxy amines. Specifically, monoethanolamine, triethanolamine, N-methylethanolamine, N-aminoethylethanolamine, N-methyldiethanolamine,
Monoisopropanolamine, diisopropanolamine, triisopropanolamine, hydroxylamine, butanolamine, hexanolamine, methyldiethanolamine, octanolamine, ethylenediamine, diethylenetriamine, triethylenetetramine, hexamethylenetetramine, tetraethylenepentamine, propylenediamine, imino-2 Diaminepropane, imino-bis-propylamine, lower mono-, di- and trialkylamines (alkyl groups C ₁ -C ₈ ), for example mono-, di- and triethylamines, reaction products of alkylene oxides with mono- or polyamines, for example , A reaction product of ethylenediamine and ethylene oxide, and sodium hydroxide, potassium hydroxide and the like. This styrene-maleic anhydride copolymer resin has a solid content of 0.5 to 19 relative to 100 parts by weight of the surface-treated titanium dioxide pigment.
It is mixed in parts by weight, but if it is less than 0.5 parts by weight, the dispersibility is poor and the paste viscosity increases. If the amount is more than 19 parts by weight, water resistance, weather resistance and gloss retention are deteriorated. In the aqueous titanium paste of the present invention, to the extent that the effects of the present invention are not lost,
Further, various additives and fillers used as usual paint formulations may be added. Examples of such compounds include thickeners such as methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose and the like, mineral-based or silicone-based defoaming agents, such as mineral oil based mineral oils, fatty acid esters, higher fatty acid metal Soap, organophosphorus compound polypropylene glycol, organic urea compounds, compounds containing insoluble substances such as hydrophobic silica, silicone-based dimethyl silicone, modified silicone such as polyether modified, hydrophobic silica silicone compound, etc. are available. Emulsified by adding or emulsified, self-emulsifying type, various wetting agents / dispersants / color separation inhibitors, high molecular weight polyacrylic acid salts, formalin condensates of naphthalene / sulfonate salts, long-chain alkyl Organic sulfonic acid salt, Salts of Guninsuruhon acid, salts of polyphosphoric acids and poly silicic acid,
Examples thereof include polyethylene glycol derivatives and sorbitan fatty acid esters. The aqueous titanium paste of the present invention has a total solid content of 60 to 75% by weight including these compounds.
Is to be

[0005]

【Example】

(Example 1) Dispersant 4 shown in Table 1 (styrene / maleic acid ratio 1.3 / 1, solid content 20%, molecular weight 1400)
0, acid value 190) at the compounding ratio shown in Table 2,
An aqueous titanium paste was produced. As a mixing procedure, first, water is put into a tank, and then a thickener, a dispersant, an additive, and titanium dioxide are added in this order while mixing and stirring with a dissolver. Was used. (Example 2 to Comparative Example 4) Similarly to Example 1, the aqueous titanium pastes of Example 2 to Comparative Example 4 were used at the respective compounding ratios shown in Table 2 using the dispersant shown in Table 1. Each was manufactured.

[Table 1]

[Table 2] <Physical Properties Test> The aqueous titanium pastes of the above-mentioned Examples and Comparative Examples were manufactured by using the test of viscosity change after storage as an index of fluidity, and the immediately after storage of an aqueous titanium paste and as an index of dispersibility, respectively. The gloss change of the white enamel and the change of the gloss retention rate of the white enamel as an index of weather resistance were tested. -Test of viscosity change after storage and before and after stirring For Example 1, Example 2, Comparative Example 1 and Comparative Example 2, the viscosity at the time of producing the aqueous titanium paste and 50 ° C x 7 days and 50 ° C x 1 The viscosity after a month was measured. The results are shown in Table 3.
It was shown to. Regarding the solid content ratio of the dispersant to the pigment, Example 1 and Comparative Example 1, and Example 2 and Comparative Example 2 have the same value, but the value of the styrene / maleic acid ratio in the dispersant used in the present invention is the same. In Comparative Example 1 and Comparative Example 2 which exceed the specified range, the change in viscosity with respect to the viscosity at the time of production was extremely large as compared with Example 1 and Example 2 both after 7 days and after 1 month. It is a value.

[Table 3] -Test of change in gloss of white enamel For Example 1, Example 2, Comparative Example 1 and Comparative Example 2, using the aqueous titanium paste immediately after production and after 50 ° C x 7 days and after 50 ° C x 1 month, Manufacture white enamel,
2 of each white enamel dry coating (film thickness 100μ)
Gloss at 0 ° and 60 ° were measured. White enamel blend is acrylic-styrene emulsion (solid content 50%)
Of 59 parts by weight, texanol of 7.6 parts by weight, aqueous titanium paste of 33 parts by weight, and antifoaming agent of 0.4 parts by weight. The results are shown in Table 4. Compared with Example 1 and Example 2, Comparative Example 1 and Comparative Example 2 showed a larger degree of decrease in gloss value after 7 days and 1 month.

[Table 4] -Test of change in gloss retention of white enamel For Example 3 and Comparative Example 2, white enamel was produced with the same composition as in the test of change in gloss of white enamel described above, and a dry coating film (film thickness 100 µ) of 20 was prepared. The gloss at 60 and 60 was measured. This coating film was immersed in warm water at 50 ° C for 1 hour and irradiated with a germicidal lamp 1
Three cycles were carried out with one cycle of 6 hours, and the gloss for each cycle was measured to calculate the gloss retention rate. The results are shown in Table 5.
It was shown to. In the solid content ratio of the dispersant to the pigment, Example 3 and Comparative Example 3 have the same value, but the value of the molecular weight of the styrene-maleic anhydride copolymer resin in the dispersant used is within the range specified in the present invention. In Comparative Example 3 exceeding 1, the deterioration of the gloss retention ratio with respect to the initial gloss was observed in Example 3 after 1 cycle, 2 cycles, and 3 cycles.
Is larger than.

[Table 5]

[0006]

EFFECTS OF THE INVENTION Due to the high pigment content, the transportation cost per same pigment weight can be reduced as compared with the conventional one, and the same effect (concealing power etc.) as the conventional one can be obtained by adding a small amount even in the paint formulation. Super weather resistant surface treated titanium dioxide and high molecular weight dispersing resin do not deteriorate the coating film, yet it has excellent dispersibility and does not cause agglomeration, etc. Even in the raw material transport pipe, the paste flows smoothly through the pipe.

Claims (1)

[Claims] 1. Styrene / maleic anhydride is used in a weight ratio of 1-1.1 to 100 parts by weight of the surface-treated titanium dioxide pigment.
Copolymerized at a ratio of 5/1 and has a molecular weight of about 5000 to 15
Styrene-maleic anhydride copolymer resin partially esterified and neutralized with a basic compound in an amount of 0.5 to 19 parts by weight in terms of solid content, and a pigment solid content ratio to the total of 60 to 75. Aqueous titanium paste with high pigment content, characterized in that it is made to be wt%.