Performance indicators of paint products -- What is the water resistance of paint products, and which types of paint have good water resistance?

Water-resistant solutions 1. Chemical cross-linking modification techniques: (modified resins, functional modifying monomers, modified curing agents, water-based silane couplings, plasticizers). Methods such as those for increasing cross-linking density and strength enable the resulting water-based coating systems to exhibit good resistance to water, alcohol, chemicals, and solvents. 2. Physical cross-linking modification techniques: These techniques make use of intermolecular forces and hydrogen bonds – with hydrogen bonds being a special type of intermolecular force. Through chemical reactions, certain functional groups are introduced into the main chain or side chains of polymers, thereby enhancing the coating’s resistance to water, alcohol, chemicals, and other substances. Considering the relationship between hydrogen bonds, crystallinity, and properties of groups such as polyurethane, acrylic, and epoxy, hydrogen bonds represent a physical attraction; they are much weaker than the bonds between atoms. Nevertheless, the presence of numerous hydrogen bonds is one of the key factors that influence the properties of polar polymers. The more hydrogen bonds there are, the stronger the intermolecular forces, and the higher the strength of the material. 3. Polymer blending and compounding modification: Two or more polymers are blended in appropriate proportions to create materials with properties that cannot be achieved by using a single polymer. By introducing certain functional groups, the water resistance, alcohol resistance, and chemical resistance of the coating are improved. 4. Copolymer modification technology: For example, copolymer emulsions modified by epoxy resins form a three-dimensional cross-linked structure during film formation, resulting in irreversible covalent cross-linking, which significantly improves the tensile strength and water resistance, as well as resistance to alcohol and chemicals, of the coating. 5. Modification technology using organic fluorine-functional monomers: By adding fluorine-containing functional monomers, the water contact angle, adhesion, and hardness of the modified resin or coating increase gradually, while the water absorption rate decreases. The tensile strength and elongation at break first increase and then decrease. The surface energy of the resin or coating is significantly reduced, and it possesses good tensile strength and water resistance. The introduction of fluorine elements addresses the shortcomings of traditional water-based polyurethanes, such as poor water and oil resistance, as well as weak resistance to alcohol and chemicals. Image 6. Multiple modification techniques: For example, pure polyurethane does not have optimal properties; by combining it with epoxy resin, the chemical resistance, toughness, water resistance, alcohol resistance, and other characteristics of the polyurethane adhesive film are improved. 7. Hydrophobic compound modification technology: Adding hydrophobic compounds to the formula can improve the hydrophobicity of the paint film, thereby reducing or minimizing penetration into the paint film. Wax emulsions and wax powders are commonly used additives to improve water resistance, resistance to alcohol wiping, and chemical resistance, among which PE wax emulsions yield the best results. Image 8. The addition of crosslinking agents (post-crosslinking agents) via modification techniques can reduce the particle size of emulsions in water-based systems, while improving the water resistance and hydrophobicity of the coating surface, as well as significantly enhancing adhesion and crosslinking density. The poor oil resistance has been improved, along with resistance to alcohol and chemicals. 9. Hydrophobic nano-modification technology: The introduction of hydrophobic nano-fillers and functional monomers enhances water resistance; for example, the composite blending and copolymerization modification method using inorganic nanomaterials such as silica sol can significantly improve properties related to oil resistance, alcohol resistance, and chemical resistance.

This post was last edited by Wang Genrong on 2021-7-21 at 10:33. Polyaniline anti-corrosion coatings have excellent water resistance, including against seawater and saltwater.

Polyaniline is regarded as a new generation of high-performance anti-corrosion material due to its readily available raw materials and simple synthesis. Since DeBerry proposed in 1985 that polyaniline films prepared by electrochemical methods possess a passivating effect on stainless steel, research and development on polyaniline for anti-corrosion purposes has become a new area of interest [1–3]. 1. Structure and properties of polyaniline: The structure of polyaniline was first proposed by MacDiarmid et al. [4], and it consists of oxidized units and reduced units. Depending on the proportion of the two units, PANI can exist in three extreme forms: the fully oxidized state (y=0, abbreviated as PNB), the fully reduced state (y=1, abbreviated as LEB), and the intermediate oxidation state (y=0.5, abbreviated as EB); these states can transform into one another. Compared to other polymers, polyaniline has the following characteristics: ① Diverse structures – experiments have shown that polyaniline in different oxidation and reduction states corresponds to distinct structures, with varying electrochemical properties as well; ② A unique doping mechanism – PANI becomes conductive through protonic acid doping, and this distinctive doping property endows it with unique corrosion-resistant capabilities.

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