In today’s coatings industry, zinc stearate is used as a polishing agent. Based on its incompatibility with the paint components, it is dispersed in the paint as a very fine suspension, and is distributed on the surface of the paint film during film formation, causing microscopic roughness on the surface of the paint film. Zinc stearate is the least soluble stearate among the five common stearates. It has excellent transparency, dispersion, adhesion, weather resistance, storage, etc.
1. Paint grade zinc stearate is a good drier and wetting dispersant:
Paint grade zinc stearate is an important paint drier. Used in conjunction with other drier, it can accelerate the drying of the paint film, improve the surface condition of the paint film, and eliminate wrinkles. , cloth texture, fogging and other defects, it can achieve uniform surface and interior, rapid drying, smoothness, plump appearance, good gloss. It is also a good wetting dispersant, which can improve the wetting properties of pigments and paints and increase grinding efficiency. , to prevent the tendency of pigments to precipitate during storage. Zinc stearate is also a stabilizer for drier agents such as cobalt, manganese, and lead, which can prevent the loss of drier force caused by certain pigments or fillers during storage. Crushing phenomenon, etc.
2. Zinc stearate has several main technical indicators in wood primers that affect the performance of the paint:
1. Sandability
In wood primer , Sanding performance is a very important indicator in paint. The usual test method is to use the same paint formula and the spray plate to be polished and tested at the same time at the same time. There is no fixed standard. If you have only used one zinc stearate coating manufacturer, it does not matter how good the grinding properties are. However, market competition has led to product comparisons and also stimulated the further development of zinc stearate grinding aids. The quality of sanding performance directly affects the speed of construction and the frequency of sandpaper replacement, which directly affects the cost of furniture manufacturers.
2. Transparency
In transparent primer Among them, the quality of transparency directly affects the beauty of wood. Therefore, zinc stearate produced by the water method cannot be used in transparent wood paint, mainly because there are too many impurities. The zinc stearate produced by the direct method can meet the purity requirements, but the process requirements are also very high. Different production processes have a great impact on transparency. It is possible that small differences in processes can lead to huge differences in transparency. . Therefore, although there are many direct-method manufacturers of zinc stearate, few can be used in the coatings industry. This is also the core technology of zinc stearate coating companies. The usual testing method for transparency is to use a certain proportion of resin, solvent, and zinc stearate to disperse, one test sample and one standard sample, and then use an applicator to apply a layer of film on black and white paper or glass to see the degree of transparency. .
3. In addition to focusing on polishing and transparency, zinc stearate also has other influencing factors such as diameter, dispersion, Thickening,, etc. also have an impact on the overall performance of wood paint:
1. Particle size of zinc stearate
Particle size is an indicator of the size of zinc stearate particles, generally Measured by fineness. Usually, the easiest and quickest test for fineness is the scraper fineness. Generally, a certain proportion of zinc powder is added to the alkyd resin to disperse, then a little solvent is added to adjust the viscosity, and then a scraper fineness meter is used to test, like this The test results will be slightly larger than the actual fineness because the resin-coated powder occupies a certain thickness. However, as long as the standards are comparable and repeatable, this testing method can be used to measure whether the fineness exceeds the standard.
In coatings, the fineness of zinc stearate should not be too large. This will cause the effect of the spray plate to be filled with particles protruding from the surface, and some Unsanded areas will show unevenness. Sometimes zinc stearate contains coarse particles, which will also have a certain impact on the aesthetics of the paint film.
2. Dispersibility of zinc stearate
During the production process of coatings, many zinc stearate manufacturers also mentioned the problem of dispersion. Under normal circumstances, there is no problem with the dispersion of zinc stearate in paint. However, during the production process of zinc stearate, some indicators will have a certain impact on the dispersion, such as the dispersion of zinc stearate. When the acid value is too high, the temperature of the semi-finished product is too high, or the workers press the package too hard, there will be problems with poor dispersion of the zinc powder in the paint. At the same time, if the moisture in the zinc powder is too high, crystallization problems will also occur, which is considered dispersion. Not good, but this problem will not occur when using zinc stearate from Jiangxi Hongyuan Chemical Industry.
3,Zinc stearateThickening
Comparison of manufacturers that produce coatingsThe thickening of zinc stearate is not acceptable, because when zinc stearate is added to the paint to make the finished product, its viscosity is determined, and the factory index is set. Even the error is within ±500mP·s, so the test is difficult. The thickening method of zinc fatty acid is generally tested with a rotational viscometer. If the deviation between the newly dispersed viscosity and the viscosity after a few hours is greater than 500 mP·s, it is considered thickening. If zinc stearate is thickened, the finished product tested by the paint manufacturer will be very different from the one used when it is used. Even the original viscosity required for the production of paint is relatively high, plus the thickening of zinc stearate, this is likely to cause The paint cannot flow at all, especially PE paint, resulting in solidification and scrapping. Therefore, thickened zinc stearate cannot or is rarely used in coatings. This is why there are many zinc stearate manufacturers but only a few manufacturers sell coating grade zinc stearate.
4. Application of water-based zinc stearate in coatings:
1. Application of water-based zinc stearate as a waterproofing agent in coatings:
Friction will cause material wear, and the way to alleviate friction and wear is lubrication. Adding water-based zinc stearate to the surface coating can reduce the effect of friction coefficient and form a self-lubricating material.
When the friction pairs slide against each other, the temperature rise generated changes the properties of the material surface, thereby affecting the friction coefficient, and varies with the working conditions of the friction pair. And change. When water-based zinc stearate is heated, it changes from solid melt to liquid, absorbs a large amount of heat, stabilizes the surface properties of the material, and reduces the friction coefficient.
During the friction process, due to the low shear strength of the lubricating coating added with aqueous zinc stearate that adheres to the surface of the substrate, it will transfer to A transfer film is formed on the surface of the dual material, causing friction to occur between the coating film and the transfer film, thereby reducing friction. Moreover, the lubricating coating film added with water-based zinc stearate can firmly adhere to the surface of the substrate and is not easy to fall off during friction. It can provide a stable and long-lasting dedicated nano film, so that the formation and consumption of the transferred nano film are balanced, so Lubrication is in good condition.
2. Application of water-based zinc stearate as wear-resistant additive in coatings
The wear resistance of wear-resistant coatings actually refers to the ability of the coating to resist friction, scratches, and erosion. It is related to many properties of the coating, including hardness, scratch resistance, and cohesion. , tensile strength, elastic mode and toughness, etc.
The commonly used wear-resistant coatings are polyurethane and its modifications, epoxy and its modifications, silicone and its modifications. Although polyurethane elastomer is recognized as an excellent wear-resistant material, it has the disadvantages of too low hardness and poor adhesion, and sometimes its performance advantages cannot be fully exerted; epoxy resin has good adhesion, and the cured ring Oxygen resin coatings have high hardness, but the coating is brittle; silicone has poor wear resistance, both of which cannot meet the needs of practical applications.
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