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    Home > Coatings News > Paints and Coatings Market > Coating classification: tf-469: a new type of high efficiency coating preservative

    Coating classification: tf-469: a new type of high efficiency coating preservative

    • Last Update: 2020-04-03
    • Source: Internet
    • Author: User
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    Core tip: Introduction: In the development of coatings industry, environmental friendly waterborne coatings are becoming the focus of the market Among many coating additives, the safety and environmental protection of preservatives are the most important This is because the existence of water is one of the necessary conditions for the growth and reproduction of microorganisms Various additives rich in nutrients, such as thickeners, provide more favorable conditions for the growth of microorganisms The pollution of bacteria, mould and other microorganisms will lead to a series of problems, such as discoloration of the product surface, poor sagging performance, increased acidity, deterioration of service performance, agglomeration, demulsification, peculiar smell, even mildew on the surface, and gas flushing, etc Application scope and advantages of roller ceramic coating Recommended introduction: the surface of ceramic rubber plate used for roller ceramic coating is cast into durable rubber plate by hundreds of independent small ceramic pieces Each ceramic piece has raised characteristics Under general conveyor belt pressure, thousands of unique cast bumps can produce positive traction, prevent slipping and extend the service life of conveyor belt roller At the same time, the bottom layer adopts high-quality rubber, which has strong elasticity and can play a good impact resistance role The scope of application of roller ceramic coating is one three six 83857180 (the same as V) 1 Roller coating in extremely harsh working environment 2 The belt joint is not suitable for fixing with iron buckle; 3 It is suitable for leather Introduction: in the development of coatings industry, environmental friendly waterborne coatings are becoming the focus of the market Among many coating additives, the safety and environmental protection of preservatives are the most important This is because the existence of water is one of the necessary conditions for the growth and reproduction of microorganisms Various additives rich in nutrients, such as thickeners, provide more favorable conditions for the growth of microorganisms The pollution of bacteria, mould and other microorganisms will lead to a series of problems, such as discoloration of the product surface, poor sagging performance, increased acidity, deterioration of service performance, agglomeration, demulsification, peculiar smell, even mildew on the surface and gas flushing In order to protect the storage and use of waterborne coating products, many manufacturers will think of adding preservatives to their products But many times preservatives still can not play an ideal role, and even bring other problems, such as caking, demulsification, viscosity abnormality, etc Therefore, in order to control the growth of microorganisms, anticorrosion technology and selection of preservatives are very important In the development of preservative technology for several years, a new type of preservative was developed by analyzing the advantages and disadvantages of various preservatives at home and abroad, combining with a large number of application data and cases Introduction of commonly used preservatives: there are many kinds of preservatives for waterborne coatings on the market, but only a few are commonly used The analysis of their active components can be divided into the following categories: isothiazolinone, formaldehyde releasing, benzimidazole, organic bromine, organic amines, triazine, etc 5-chloro-2-methyl-4-isothiazoline-3-one / 2-methyl-4-isothiazoline-3-one, referred to as CMIT / MIT, collectively referred to as Casone, is a common preservative with high cost performance in tanks Because the upper limit of pH value is 8-9, just the pH range of conventional waterborne coatings, a little carelessness in use will lead to corrosion failure In addition, conventional Casson contains about 25% magnesium salt, which will bring other adverse effects to the coating 1,2-benzoisothiazoline-3-one, referred to as bit, has a higher pH value than that of Casone, but its water solubility is not good and its price is also high It is usually not used alone It can be combined with Casone to improve alkali resistance and use at a proper high temperature There are many kinds of formaldehyde type preservatives Formalin is 35% - 45% formaldehyde solution In the past a long time, formaldehyde is the most widely used and cheapest preservative for coatings Since the national formal implementation of 100 ppm formaldehyde limit for interior wall coating, formaldehyde is the primary condition for everyone to evaluate the quality of coating Due to the strict requirements of free formaldehyde content in domestic wall coatings, the use of formaldehyde releasing preservatives in interior walls is limited It belongs to formaldehyde releasing preservatives such as n-formaldehyde, o-formaldehyde, DMDMH, sodium hydroxymethylglycine, etc In fact, formaldehyde release preservatives have their inherent advantages, such as good space protection It is unscientific to give up the use blindly If it can be used in combination with other preservatives, the formaldehyde content will not exceed the standard, and it will have a good anticorrosive effect 1,3,5-tris (2-hydroxyethyl) - triazine is a product of the reaction of organic amines with formaldehyde Due to its pH value of 9-11, it has good alkaline resistance, moderate relative price and convenient addition Formaldehyde may be released during sterilization, and its use is restricted artificially 2,2-dibromopropamide, or DBNPA for short, has a very fast sterilization speed 1-2 min can eliminate the peculiar smell of the coating Usually 20% polyethylene glycol solution is used as commodity It has poor alkali resistance and its half-life is about 20 min when pH is 9 It is not suitable to be used as a preservative It can be combined with other preservatives to quickly kill microorganisms in raw materials or production systems Composite preservative is a new direction of preservative development It is widely praised because of the following advantages: ① quick sterilization and long-term antibacterial; ② the antibacterial spectrum of concentrated preservatives can be complementary; ③ the protection range (space) of preservatives is increased; ④ the pH value of preservatives is extended; ⑤ the dosage of preservatives is reduced; ⑥ the stability of high and low temperature is improved; ⑦ the use cost of composite preservatives is reduced; ⑧ The composite adaptability of preservatives with different sterilization mechanism is better; ⑨ the toxicity of preservatives is reduced and the safety is improved According to the characteristics of the above composite preservatives, the new high-efficiency coating preservative tf-469 is introduced below Tf-469, a new type of high-efficiency coating preservative: the main component of the coating formulation design the conventional Casone contains a large amount of magnesium nitrate (about 23-28%) as a stabilizer At the same time, due to the needs of the production process of Casone, about 3-8% magnesium chloride is preferred, so there are a large number of Mg2 + ions in Casone, which often lead to emulsion condensation (salt cluster), and have a negative impact on the rheological properties of the coating Te-469 does not use magnesium salt and divalent metal ions as stabilizers to effectively avoid the "salt cluster" effect Tf-469 is compounded with at least two other preservatives to make up for the poor killing ability of Casson to Pseudomonas and mould The stability of tf-469 was improved and its germicidal efficacy was enhanced by using at least three additives In the formula, the broad spectrum, pH applicability, environmental protection and safety of sterilization are effectively considered Physical property parameters during the manufacturing process, add deionized water of specified amount into the reactor, add additives to dissolve, adjust the acidity, then add several preservatives to mix evenly, pass the inspection and filter the package Tf-469 performance test: stability: tf-469, Cu2 + stable and Mg2 + stable conventional Casone were prepared into the same concentration, and were observed at room temperature and stored at 40 ℃ There is no obvious change in the three at room temperature for 12 months, and the stability is good; however, tf-469 shows better stability at constant temperature of 40 ℃, as shown in the table below The effect of Ø on the latex of the coating, 5 ml preservative was added into 10 ml latex drop by drop, and the change of latex was observed The results show that tf-469 has no adverse effect on the general latex for coating, and the control sample appears latex condensation in some cases This is the reason why sometimes the coating has caking and poor fluidity, and these situations often do not cause the vigilance of coating technicians What's more dangerous is that once the agglomerates are filtered out, it is likely to cause poor corrosion protection, because there are relatively more preservatives in the agglomerates On the other hand, the magnesium salt contained in 1-2kg conventional Casson preservative added to each ton of coating is equivalent to transforming one ton of softened water into tap water with high hardness It can be seen that the effect of Mg2 + in conventional Casson is worthy of high attention See the table below The effect of thickening agent on thickening agent of coating is commonly used as thickening agent in the coatings, such as cellulose, such as HEC, and associating thickening agent, such as associative HASE, is hydrophobically modified polyacrylic acid alkali swelling emulsion The thickening mechanism of alkali swelling thickener is first because it can adsorb on the surface of emulsion particles to form a coating layer, which increases the viscosity of emulsion particles and leads to the increase of viscosity Secondly, it can also enter the aqueous system to increase viscosity In addition, it mainly depends on the attraction repulsion of the dissociated carboxylic acid ions under the alkaline condition to make the helical molecular chain stretch into rod-shaped thickening, so its thickening efficiency is very sensitive to pH, and it must reach pH 8.0 to make it fully play the thickening role: the thickening mechanism of the associative polyurethane thickener HEUR lies in the presence of water repellent and strong polar groups in their molecules, which can be used with latex paint The polymer and pigment associate to form instantaneous network structure The coating with better application and film-forming characteristics can be obtained by using association thickener compared with traditional cellulose thickener The main chain of HEUR thickener is hydrophilic and can form hydrogen bond with water under normal conditions However, in the environment with high ion concentration, water is more likely to combine with ions, which causes the main chain dehydration and makes the thickener insoluble The thickener can not play a good role, and phase separation occurs on the micro scale, resulting in flocculation, which leads to the decrease of liquidity and luster Any raw material with high ion content will lead to the decrease of the solubility of HEUR thickener The alkali swelling association type hase thickener and association type polyurethane HEUR thickener are respectively mixed with softened water to a concentration of 4%, adjusted to a pH value of 8-9, added with preservatives, and observed the viscosity change, as shown in the table below It can be seen that the alkali swelling association type hase thickener is very sensitive to divalent metal ions, and the viscosity drop is amazing when using conventional Casson preservative; relatively speaking, the association type polyurethane HEUR thickener is not too sensitive when the content of divalent metal ions is low This method is mainly used to determine the inhibition of Fungicides on bacteria, mold, yeast and other microorganisms In this method, a certain concentration of antiseptic solution is injected into a certain volume of steel ring, and the steel ring is located on the plate with bacteria on the surface At the appropriate temperature for a certain period of time, observe and measure the size of the bacteriostatic circle The large bacteriostatic circle indicates that the bacteriostatic ability of the bactericide is strong This method is affected by the diffusion ability of bactericide on agar plate, and has some errors However, it is still often used because of its advantages such as simple operation, visual recognition and good visualization If the preservative with the same concentration is diluted to 0.4% and added to the beef culture medium with mixed bacteria, culture at 37 ℃ for 18 h, and measure the size of the bacteriostatic circle, as shown in the table below It can be seen that tf-469 has the best antibacterial effect, which is the advantage of composite preservatives The industrial application of tf-469 preservative in coating industry has achieved a very good comprehensive effect after a large number of industrial applications Not only the anticorrosion effect is better than the conventional preservative, but also a large number of thickeners are saved The value of the thickener saved is far more than the use cost of the preservative by 3-10 times, and the rheological property of the coating is also improved Here is a production example It can be seen that the use of tf-469 preservative in system 1 and system 2 can save 47% and 38% of thickener respectively compared with conventional Casone, and the rheological property is effectively improved The application in the past year shows that tf-469 preservative has a good development prospect in the coating industry, and it is worth promoting Paint house is focused on coatings, diatom mud, paint coating, coating technology, fire retardant coating news and coating, diatom mud, paint coating, coating
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