JPS595628B2 - Manufacturing method of fine particle calcium carbonate pigment for paints - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a fine-particle calcium carbonate pigment which, when incorporated into a paint as an extender pigment, has extremely good dispersibility and provides excellent coating gloss.

Conventionally, methods of treating the surface of calcium carbonate with anionic surfactants, cationic surfactants, nonionic surfactants, etc. have been known as methods for improving the suitability of fine-particle calcium carbonate for paints. The surface-treated fine-particle calcium carbonate obtained by this method has, for example, improved dispersibility in a paint resin solution or improved coating film gloss compared to untreated fine-particle calcium carbonate.

However, originally calcium carbonate pigments are often used together with titanium white, a white pigment, as extender pigments, and from the viewpoint of productivity in paint production, they have a dispersibility comparable to that of titanium white, preferably higher than that of titanium white. It is insufficient for general use in paints, since it is desired that there is no reduction in coating film gloss even when used in combination with titanium white. As a method to improve the suitability of fine particulate calcium carbonate for paints, a carboxylic acid type anionic surfactant such as a resin acid soap or a fatty acid soap,
Method of combined treatment with a hard water resistant surfactant such as dodecylbenzenesulfonic acid (Japanese Patent Publication No. 15771/1971)
Also, methods have been proposed in which a fatty acid ester emulsified with a surfactant is blended (Japanese Patent Application Laid-open No. 107929/1983), but even surface-treated calcium carbonate obtained by these methods cannot be used for paints. Compared to titanium white, which is commonly used as a titanium white, its dispersibility and coating gloss are still inferior.

The present inventors have researched surface treatment methods using various organic compounds for the purpose of improving the dispersibility of fine-particle calcium carbonate in resin solutions for paints and the gloss of the paint film. We have completed the invention of a fine particle calcium carbonate pigment for paints that has moderately excellent dispersibility and provides good coating gloss.

That is, the present invention combines a hard water-resistant sulfuric acid ester type or sulfonic acid type anionic surfactant and an ester of aromatic carboxylic acid to a fine particle aqueous suspension of calcium carbonate. The present invention relates to a method for producing a fine-particle calcium carbonate pigment for paints, which is characterized by treating the particle surface, dehydrating, drying, and pulverizing it, and which has extremely good dispersibility in paints and provides excellent paint film gloss. still,
In the present invention, the average particle diameter of calcium carbonate particles refers to the length of one side of a cubic crystal, which is determined from the specific surface area determined by the BET method, assuming that the calcium carbonate particles are cubic particles. The present invention will be explained in more detail below. The base calcium carbonate that exhibits the effects of the present invention is fine precipitated calcium carbonate with an average particle size of 0.08 to 0.5 μm.

When calcium carbonate with an average particle size of 0.5 to 2 μm is subjected to the surface treatment according to the present invention, the dispersibility is improved compared to that of untreated calcium carbonate, but the same level of coating gloss as titanium white cannot be obtained. I can't. Average particle size is 0.0
Calcium carbonate with a diameter of less than 8 μm gives results that are inferior to those of titanium white in terms of dispersibility and coating gloss. Calcium carbonate as a base material has excellent dispersibility to the same extent as titanium white and provides good coating gloss. Average particle size is 0.08-0.5μm
It is within the range of . Aromatic carboxylic acid esters used in the present invention include esters of phthalic acid such as octyl alcohol, butyl alcohol, and isobutyl alcohol, lower alcohol esters of naphthoic acid,
Examples include lower alcohol esters of rosin acid.
In the case of aromatic polycarboxylic acids such as aromatic dicarboxylic acids or maleic acid adducts of rosin acid, effects can also be obtained with partial esterification products of the carboxylic acids or esterification products of different alcohols. Further, the total amount of the aromatic carboxylic acid ester and sulfuric acid ester or sulfonic acid type anionic surfactant required to achieve the effects of the present invention is 0.000 parts by weight per 100 parts by weight of calcium carbonate. It is in the range of 5 to 10 parts by weight. The anionic surfactant added together with the aromatic carboxylic acid ester is sufficient for the purpose of emulsifying the aromatic carboxylic acid ester in a ratio of 2 parts by weight or less per 10 parts by weight of the aromatic carboxylic acid ester. However, in order to make the anionic surfactant to be added effectively act on the dispersion of the calcium carbonate particles in water, aromatic carboxylic acid ester 10
The anionic surfactant must be added in an amount of 5 parts by weight or more based on the weight part. However, the combined addition of 20 parts by weight or more of the anionic surfactant is not only uneconomical as it unnecessarily flows out into the wastewater, but also leads to the formation of excessive foam, resulting in deep dewatering of the treated calcium carbonate suspension. It has the disadvantage of significantly reducing work efficiency. Therefore,
The optimal combination addition ratio of sulfate ester type or sulfonic acid type anionic surfactant is 10% of aromatic carboxylic acid ester.
The amount is 5 to 20 parts by weight. The aromatic carboxylic acid ester and the anionic surfactant are added by adding the surfactant aqueous solution to an aqueous suspension of calcium carbonate while stirring, and then adding the aromatic carboxylic acid ester.

Alternatively, a method can be adopted in which the surfactant and the aromatic carboxylic acid ester are added at the same time, but a more preferable method is to form an emulsion of the aromatic carboxylic acid ester with the surfactant aqueous solution and then add the emulsion. Next, Examples will be given to further clarify the features of the present invention.

Examples 1-2 First, water 279 was added to hydrogenated rosin methyl ester 39, heated to 50°C, and while stirring strongly, a separately prepared 10% aqueous solution of dodecylbenzenesulfonic acid 209 was injected.
Hydrogenated rosin methyl ester emulsion 5 containing hydrogenated rosin methyl ester 39 and dodecylbenzenesulfonic acid 29
While stirring a 10% aqueous suspension 10009 of precipitated calcium carbonate having an average particle size of 0.08 μm prepared from 09,
The previously prepared emulsion 509 of hydrogenated rosin methyl ester with dodecylbenzenesulfonic acid was added, and stirring was continued for 30 minutes, followed by suction, filtration, drying at 60°C, and pulverization to give an average particle size of 0. A calcium carbonate pigment for paint with a diameter of 0.08 μm was obtained.

(Sample of Example 1) Precipitated calcium carbonate having an average particle diameter of 0.2 μm was subjected to surface treatment according to Example 1 to obtain a calcium carbonate pigment of the present invention having an average particle diameter of 0.2 μm. (Example 2 sample) Comparative examples 1 to 2 As a comparative sample of Examples 1 and 2, the average particle size was 0.03μ.
Precipitated calcium carbonate of m1 and 2 μm was subjected to surface treatment according to Example 1, and precipitated calcium carbonate of 0.03 μm and 2 μm was
m of the surface-treated calcium carbonate was obtained.

(Comparative Examples 1 and 2 samples, respectively) Example 3 According to Example 1, an emulsion was prepared using dibutyl phthalate as the aromatic carboxylic acid ester, and the average particle size was 0.0.
Precipitated calcium carbonate having a diameter of 8 μm was subjected to surface treatment to obtain a calcium carbonate pigment for paints having an average particle diameter of 0.08 μm according to the present invention.

(Example 3 sample) Example 4 According to Example 1, an emulsion of hydrogenated rosin methyl ester was prepared using sodium lauryl sulfonate, and surface treatment was applied to precipitated calcium carbonate with an average particle size of 0.08 μm. The average particle diameter according to the present invention was 0.08 μm.
A calcium carbonate pigment for paint was obtained.

(Example 4 sample) Example 5 According to Example 1, an emulsion was prepared using hydrogenated rosin methyl ester 19 and dodecylbenzenesulfonic acid 19, and the surface was coated with precipitated calcium carbonate having an average particle size of 0.08 μm. The average particle size according to the present invention is 0.08μ.
A calcium carbonate pigment for paints was obtained.

(Sample of Example 5) Comparative Example 3 While stirring a 10% aqueous suspension of precipitated calcium carbonate 10009 having an average particle diameter of 0.08 μm, 20 f! of a 10% aqueous solution of dodecylbenzenesulfonic acid! Then, 10% aqueous solution 309 of hydrogenated rosin soda was added, stirring was continued for 30 minutes, the mixture was filtered under suction, dried at 60° C., and pulverized to obtain surface-treated calcium carbonate.

(Comparative Example 3 Sample) Comparative Example 4 In Example 1, an emulsion was prepared using oleic acid methyl ester, which is a fatty acid ester, in place of hydrogenated rosin methyl ester, which is an aromatic carboxylic acid ester, and the average Surface treatment was performed on precipitated calcium carbonate with a particle size of 0.08 μm.

Surface-treated calcium carbonate was obtained. (Comparative Example 4 Sample) Comparative Example 5 According to Example 1, hydrogenated rosin methyl ester 3
f! , and dodecylbenzenesulfonic acid (0.59 μm), and precipitated calcium carbonate having an average particle size of 0.08 μm was surface-treated to obtain surface-treated calcium carbonate.

(Comparative Example 5 Sample) Comparative Example 6 While stirring 10% aqueous suspension 10009 of precipitated calcium carbonate with an average particle size of 0.08 μm, hydrogenated rosin soda 1070 aqueous solution 309 was added, and after continued stirring for 30 minutes, After suction filtration and drying at 60°C, the mixture was pulverized to obtain hydrogenated rosin-treated calcium carbonate.

(Sample of Comparative Example 6) Comparative Example 7 In Comparative Example 3, a predetermined amount of sodium stearate was added in place of hydrogenated rosin soda to obtain calcium carbonate treated with stearic acid.

(Comparative Example 7 Sample) Hereinafter, the properties of the samples obtained in Examples and Comparative Examples when blended into paints will be compared. (1) Dispersibility of Millbase In a glass bottle with a content of 160 cc, add 20 weight diluted mineral spirits of soybean oil-modified long oil alkyd resin. solution 259, calcium carbonate-based sample 179 (however, in the case of control titanium white, the same pigment volume concentration (PVC
) and 3m77!
A glass bulb 1209 having a diameter of φ was taken and shaken using a paint conditioner manufactured by Red Devil Co., Ltd., and the degree of sluggishness was measured over time.

The viscosity of the millbase that was shaken and dispersed for 30 minutes was measured using an Ostwald viscometer, and after the same dispersion, the millbase was wet applied to a paint test paper to a thickness of 3mil (75μm), and the dried coating film was coated with a viscosity of 60μ-60. Gloss was measured.

The results are shown in Table 1. It can be seen that all of the surface-treated calcium carbonates according to Examples have good dispersibility and provide high-gloss coatings. (2) Mixed paint properties and content 22
Measure out the following milbase formulation into a 5CC glass bottle,
Using Red Devil's paint conditioner,
After shaking and dispersing for 20 minutes, alkyd resin, dryer, anti-skinning agent, etc. for preparing mixed paint were added.
The mixture was shaken for 0 minutes to prepare a blended paint.

Table 2 shows the dispersibility of the mill base, the viscosity of the prepared coating material, and the gloss of the coating film that was applied wet to a thickness of 3 mil (75 μm) and dried. Compounded mill base titanium white (“Type 259-A” manufactured by Ishihara Sangyo Co., Ltd.)
R-550) Sample (surface treated calcium carbonate) 25
9 Soybean oil modified long oil alkyd resin solution 35fI [“Betucosol” P-470 manufactured by Dainippon Ink and Chemicals Co., Ltd.
-70 (NV-7070)] Mineral spirit diluted solution (NV-2570) Glass bulb (diameter 3m01809 Prepared soybean oil modified long oil alkyd resin solution 309 (same as above) (NV-70%) Naphthenic acid dryer (metal Content 0.4596.0%, CO:Zr-1:2) Anti-skinning agent (Dainippon Ink Chemical 0.159 “Skinner TM” manufactured by Kogyo Co., Ltd.) Pigment volume concentration: 35.970 ]:;) It is clear that the prepared paints in which the surface-treated calcium carbonate according to the examples was used in combination with the titanium white-containing paints also had good dispersibility and high paint film gloss.

Claims (1)

[Claims] 1. An aqueous suspension of finely divided calcium carbonate having an average particle diameter of 0.08 to 0.5 μm, an anionic surfactant of the sulfuric acid ester type or sulfonic acid type having hard water resistance, and an aromatic A method for producing a fine particle calcium carbonate pigment for paints, which comprises treating the surface of calcium carbonate particles by adding an ester of group carboxylic acid in combination, followed by dehydration drying and pulverization. 2. Fine particles for paint according to claim 1, wherein 5 to 20 parts by weight of a sulfuric acid ester type or sulfonic acid type anionic surfactant is added to 10 parts by weight of the ester of aromatic carboxylic acid. Method for producing calcium carbonate pigment.