Selection of fungicides that meet the requirements of green water-based building coatings (2)

3 The choice of fungicides for green water-based building coatings
in accordance with the role of fungicides in water-based building coatings, it can be divided into the production, storage and use of the process of playing a role in the wet tank preservatives, dry-film anti-mold agent and dry-film anti-algae three categories, as described below.
3.1 tank preservatives
water-based paint building coatings with water as a dispersion medium, and rich in a variety of nutrients can nourish the components, such as lotions, cellulose, other polymers, all kinds of powders, so it is the ideal breeding ground for microbial growth and reproduction. Bacteria once breeding, it is easy to grow quickly, in a very short period of time may make paint products corrupt and bad, the occurrence of slime, broken milk, acid, odor, quality decline and even scrap, to bring economic and goodwill losses to enterprises. This broken ring can occur in the paint production process, may also occur in the paint storage, transportation, or even in the construction process to open the product not used in time, so the proper addition of preservatives in the tank is to ensure the quality of water-based building coatings necessary to ensure the guarantee.
3.1.1 In-tank preservative activity overview
Water-based coatings commonly used in tank preservative activity are: formaldehyde, bromide nitrool, CIT, MIT, BIT, 2,2-dibromo-3-sub-nitrogen acrylamide (DBNPA) and so on, its main characteristics are listed in Table 6.can be seen in Table 6, formaldehyde, bromine nitrosol, DBNPA, and CIT have rapid sterilization, while MIT and BIT have long-lasting properties. Considering the growth law of bacteria and the production process of water-based building coatings, it is necessary to take into account rapid sterilization and long-lasting protection in order to ensure product quality stability.
3.1.2 In-tank preservative compound
a single fungicide active may not have a broad spectrum, or may not be easily made into a stable commodity, such as the CIT stability issues mentioned in Table 6. Therefore, in order to increase synergies, stabilize product performance, make up for the lack of individual products, easy to use, commercially available tank preservatives have a lot of compounding products to choose from, such as the already widely used CIT/MIT-3/1 quality ratio of compounds (also known as "cason"), cassoon and formaldehyde compounds, MIT/BIT compounds and so on.
1 is a MIC (minimum bactericide concentration) comparison of CIT, MIT, BIT, and its compounds. It can be seen that the co-ordinated effects of the in-tank fungicide recomboulation, e.g. for Bacillus green, the MIC using BIT alone is 150 x 10-6, the MIC using MIT alone is 30 x 10-6, and the MIT/BIT recommunication MIC is 20 x 10-6. This shows that by re-matching, the amount of active substance can be reduced.3.1.3 Green labeled in-tank preservatives program
In view of the very low limit of free formaldehyde in green water-based interior and exterior wall coatings, the formula to apply for green products should try not to use formaldehyde, formaldehyde releasers as preservatives. Cit/MIT (3/1) has a limit of less than 15mg/Kg and cannot be added more than 0.1% of the total formula weight if a conventional 1.5% concentration of CIT/MIT (3/1) is used; DBNPA can be used as a quick-kill preservative in whole or in part in hot and humid areas, seasons, and production environments where it is difficult to control, while the use of MIT and BIT requires consideration of total IT limits, which can significantly increase the space for mold inhibitors to use IT..