Copper pyrithione aggregate and its uses_Industrial additives

Background technology of copper pyrithione aggregates and their uses

Japanese Patent No. 3062825 discloses a method of adding a surfactant in the manufacture of copper pyrithione for the purpose of preventing gelation and accelerating reactions caused during the manufacturing process. If an inorganic copper (II) salt is added to a pyrithione alkali metal salt solution under the pH 3-8 conditions described in the claims of this patent, fine crystals of the alkaline copper salt will form before copper pyrithione is produced. Precipitate first. This is what is known as gelation. Copper pyrithione is obtained through the reaction of a slightly soluble alkaline copper salt and an alkali metal pyrithione salt. The crystals of the product are small, and the average particle size does not exceed 5 μm. In addition, alkaline copper salts remaining as impurities in copper pyrithione products cause the paint to gel during storage when blended into ship bottom antifouling paint.

Japanese Patent No. 3532500 describes reacting a pyridinethione metal aqueous solution and an inorganic copper (II) aqueous solution at a high temperature in the pH range of 1.6-3.2, and then adding the inorganic copper (II) salt. Method for producing heat-treated copper pyrithione. In the first step of this method, bipyridinethione (dimer) is easily generated by oxidation of pyridinethione acid under the production conditions of low pH and high temperature for a long time. In the second step, bipyridine is Thermal decomposition of thione and supplementation of inorganic copper (II) salt can provide a method to improve the purity of copper pyrithione. Therefore, in the second step, although the amount of production is limited, the alkaline copper salt precipitates first as shown above. The average particle size of copper pyrithione obtained by the production method of this patent is smaller than the average particle size of copper pyrithione obtained by the production method of Japanese Patent No. 3062825 because less basic copper basic copper carbonate is produced. The particle size is exceptionally large, and even then, as shown in the patent claims, it does not exceed 5 μm.

Copper pyridinethione aggregate and its use Contents of the invention

When copper pyrithione is blended into ship bottom coatings, the most important factor affecting its antifouling effect is the dissolution rate into seawater, that is, the solubility in water, which is determined by the surface area of ​​the particles. It is considered that the average particle diameter of copper pyrithione obtained by Japanese Patent No. 3062825 is suitable in cold zone sea areas, and that the average particle diameter of copper pyrithione obtained by Japanese Patent No. 3532500 is suitable in temperate sea areas. However, considering that even the copper pyrithione obtained in Japanese Patent No. 3532500 elutes into seawater too quickly in tropical seas, it is necessary to develop pyridine with a larger average particle size in order to slow the elution into seawater. Copper Thione. In addition, conventional copper pyrithione products are easily dusty at work sites, and once inhaled into the lungs, they pose health concerns due to their needle-like crystals.

Embodiment of the invention of copper pyridinethione aggregate and its use

The following examples are given to illustrate the present invention in detail. The following examples are for illustration and do not limit the scope of the present invention.

Add 3.0g copper (II) sulfate 5-hydrate and 1.5g ammonium sulfate to 40 mL of water in a beaker, and further add 5% sulfuric acid to prepare a copper (II) sulfate·ammonium sulfate complex with a pH adjusted to 2. Saline solution (A). Next, 8.85 g of a 40% aqueous solution of sodium pyrithione (specific gravity 1.20) was added to 50 mL of water in the beaker to prepare a sodium pyrithione dilute aqueous solution (B). Maintaining the temperature at 25°C, drop (B) into (A) while stirring within 30 minutes. During this period, 5% sulfuric acid was added appropriately to keep the pH from exceeding 3. Filter the obtained green copper pyrithione slurry, repeat 3 times, put the filter residue back into 100 mL of water, stir and then filter, dry the obtained solid, and grind it in a mortar to obtain 3.6 g of green granular material. .

Pyridinium dichromate

The median diameter of the substance obtained by dispersing the green granular substance into a 0.1% DEMOLN (DemoluN) (Kao Corporation) aqueous solution was measured using a laser diffraction particle size distribution measuring device, “LA-” of Horiba Manufacturing Co., Ltd. The result measured at 920” is 10.6μm. Furthermore, the median diameter after the ultrasonic function of the device was applied for 1 minute was 9.5 μm. The tendency of the value to decrease as the ultrasonic exposure time increases is the same as that of commercially available copper pyrithione.

To observe the internal state of the particles, photographs were taken at 6,000 times (Figure 2) and 30,000 times (Figure 3) using an electron microscope. The result was judged to be an aggregate of ellipsoidal and rod-shaped copper pyrithione substances having an internal length of 0.1 to 1.0 μm.

Next, in order to study the chemical composition of the aggregate, X-ray diffraction analysis was performed. As a result, the peak positions seen in the graphs (Figures 4 and 5) of this green granular aggregate and commercially available copper pyrithione (manufactured by Kolon Life Sciences Co., Ltd.) were exactly the same, so it was confirmed that the green granular aggregate is essentially pyridine. Copper Thione.

The copper pyrithione granular aggregate was further dispersed in water and stirred at 80°C for 30 minutes. After stirring, there was a faint ammonia odor and the aggregate was destroyed by about several dozen percent. This indicates that the aggregate contains a water-soluble ammonia compound. Considering the process of producing copper pyrithione from copper(II) sulfate·ammonium sulfate complex salt and sodium pyrithione, it is speculated that the ammonium sulfate dissociated during the reaction is converted into pyrithione. Copper ketone is adsorbed and linked between copper pyrithione. That is, it is considered that a complex is formed. But in X-rayNo trace of it was found in the diffraction pattern, so it is presumed that the content of ammonium sulfate is trace.