Water-based acrylic acid-epoxy-polyurethane dispersoid and alcohol-rubbing-resistant and alkali-resistant coating

Abstract

The invention provides a water-based acrylic acid-epoxy-polyurethane dispersoid and an alcohol-rubbing-resistant and alkali-resistant coating; the coating is non-toxic and pollution-free, and the properties of high temperature resistance, alcohol rubbing resistance, fingerprint resistance, flexibility, coating property and the like are good. A preparation method of the dispersoid comprises the following steps: 1) carrying out a reaction on an epoxy compound with a micromolecular alkyd compound to prepare epoxy polyol; 2) carrying out a reaction on epoxy polyol, hydrophilic polyurethane and a chain extension cross-linking agent to prepare water-based epoxy resin modified polyurethane, and neutralizing, shearing and dispersing to obtain an ester mixed emulsion; 3) mixing and dissolving the mixed emulsion and an acrylate monomer, and shearing and dispersing to obtain a ternary system mixed emulsion; 4) after the mixed emulsion is subjected to a chain extension reaction, adding an initiator and a polymerizable monomer containing keto-carbonyl, carrying out a reaction, then adding a reactive monomer containing hydrazide groups, mixing and dissolving, and 5) removing the solvent to obtain the water-based acrylic acid-epoxy-polyurethane dispersoid.

Description

technical field [0001] The invention relates to a water-based alcohol-resistant rubbing / alkali-resistant coating composition for metal based on a water-based acrylic-epoxy-polyurethane dispersion, a preparation method thereof, and an application in metal coating, especially the coating of metal coils. Background technique [0002] The pre-coating coating for metal coils is based on cold-rolled steel sheets, galvanized steel sheets, galvanized steel sheets, aluminum-magnesium alloys, aluminum sheets, etc., and adopts a fast and highly automated production line of roller coating. The steel sheets are degreased and chemically treated. , Primer coating, high temperature baking, top coating, high temperature baking to form a film, after curing to achieve a certain physical and mechanical properties, scratch resistance, alcohol rubbing, boiling, salt spray, alkali resistance and other properties Professional paint. [0003] The coated metal coils are widely used in home appliance...

AI Technical Summary

Problems solved by technology

[0008] CN105542630A discloses a polyester paint for water-based coil coatings and a preparation method thereof. The polyester resin is used as a film-forming substance, and the prepared coating has excellent scratch resistance, corrosion resistance, solvent resistance, and good flexibility. Easy hydrolysis, short storage time, poor storage stability, poor weather resistance, etc.

[0009] US5389704A discloses an epoxy phosphate primer for coils and a preparation method thereof. The prepared coating has good corrosion resistance, chemical resistance, thermal stability and flexibility, but T-bend performance, yellowing resistance Poor denaturation performance and stability, the scope of application is limited, in addition, this coating is a solvent-based product, the system has high VOC, which is not conducive to environmental protection

[0010] CN102827325A discloses a preparation method and application of a core-shell polyurethane / acrylic composite emulsion. The core-shell polyurethane / acrylic composite emulsion prepared by it is combined with a water-based amino resin or a water-based blocked isocyanate resin cross-linking component to prepare a The two-component stoving-dry coating with low organic content can be used as a low-VOC water-based coil coating, but this coating needs to be prepared immediately, the pot life of the finished paint is relatively short, the PMT temperature needs to be higher than 200°C, and the energy consumption is high.

[0011] CN101434133A discloses the preparation and application of a kind of acrylic urethane resin for surface treatment of metal plate. The acrylic urethane resin containing ketone hydrazine room temperature self-crosslinking contains anionic surfactant, which causes its hydrophilicity. Increase, water boiling resistance, alkali resistance, chemical resistance decrease, and use highly active glycidoxy silane coupling agent as the post-crosslinking part of the resin, the epoxy group reacts with the carboxylic acid, and the siloxy group hydrolyzes Polycondensation will lead to unstable coating system, short storage time and other problems

In addition, epoxy resin is a polyhydroxy compound, which is introduced into the main chain of polyurethane as a branch in the polyurethane reaction, so that the crosslinking is more sufficient and the performance is more excellent, but it is less used in the modification of waterborne polyurethane resin

This is because there are some epoxy groups in the molecular chain of the polyurethane prepolymer, and the epoxy groups are easy to react with carboxylic acid, hydroxyl, amino group or other active groups, and the ring opening of the epoxy will increase the molecular weight and improve the stability of the emulsion. decline

Images