China's wood-based high-grade coatings mainly include polyurethane paint (PU) and polyester paint (PE). There are two major types of coatings in the national standard classification, which are very different in terms of category, composition, performance, application and curing mechanism.
1. Composition base material: Polyester paint (PE): unsaturated polyester, cross-linking monomer; polyurethane paint (PU): polyester, acrylic resin, polyether, epoxy resin (hydroxy-OH-containing) The component is often referred to as the main component or the component B) an adduct or prepolymer of a polyisocyanate group (containing an isocyanato-NCO component)
2. Number of components Polyester lacquer (PE): 3-4 components, 3 components are non-wax polyester lacquers, and 4 components are waxy polyester lacquers. Component one is a styrene solution (main agent) of unsaturated polyester; component two is an initiator (also known as curing agent, hardener, common name white water); component three is an accelerator (common name Lanshui) Component 4 is a 4% paraffin styrene solution. Polyurethane lacquer (PU): 1-3 components, one-component, two-component, the latter also has a thinner when adjusting the paint, the general ratio of paint is: main agent: curing agent: thinner is 1:0.5 -1:0.5-1.5
3. Classification of polyester paint (PE): PE gas-dissolved PE and anaerobic PE, anaerobic PE and wax-type PE and non-wax PE; polyurethane paint (PU): PU sub-component and double Minute, one-component urethane oil and urethane alkyd. There are many types of PU, and the market is mainly a two-component hydroxyl-curing PU.
4. Solvent polyester paint (PE): styrene, etc. (ie solvent and film-forming substance); polyurethane paint (PU): anhydrous xylene, anhydrous cyclohexanone or anhydrous butyl acetate
5. Solid content polyester paint (PE): close to 100%; polyurethane paint (PU): 40-70%
6. Construction time limit (use period and active period of paint) Polyester paint (PE): 15-20min; Polyurethane paint (PU): 4-8h
7. Curing conditions and mechanism Polyester lacquer (PE): traditional anaerobic polyester needs oxygen curing (wax sealing method), new air-drying polyester does not need oxygen barrier curing, unsaturated polyester and styrene in initiator Free radical polymerization occurs under the action of a promoter to crosslink and solidify into a film. Polyurethane lacquer (PU): It can be dried at room temperature or at low temperature (50 °C). The solvent in the coating is volatilized, and an addition polymerization reaction occurs between the isocyanate-containing component and the hydroxyl group-containing component to form a film.
8. Hygienic conditions for construction Polyester lacquer (PE): It is a solvent-free lacquer. The solvent contained in the lacquer is coated with the unsaturated polyester after co-polymerization. The film formation is basically free of harmful gases. Polyurethane paint (PU): It is a solvent-based paint. It contains 30-60% organic solvent. It needs to be completely volatilized after painting. It pollutes the environment, is toxic and odorous, flammable and explosive, requires enhanced ventilation, and harmful substances (volatile organic compounds). , benzene, toluene, xylene TDI and heavy metals) limited national standards "room decoration materials solvent-based coatings in hazardous substances" GB18581-2001 has been clearly defined.
9. Drying time polyester lacquer (PE): surface drying 30-40min, grinding 6-10h, solid drying>24h; polyurethane lacquer (PU): surface drying 15-20min, grinding 3-4h, solid drying <24h
10. Recoating interval polyester paint (PE): It can be used as “wet-on-wet†process, that is, dry-coating; polyurethane paint (PU): “wet-on-wet†process, that is, dry-coating
11. Performance polyester paint (PE): The paint film has excellent comprehensive physical and chemical properties and unique characteristics of solvent-free paint; polyurethane paint (PU): paint film with excellent comprehensive physical and chemical properties
The so-called "polyester paint" that is common on the market today is actually a polyurethane paint. It is a two-component, one is the main paint, the other is the curing agent, mixed in the required proportion when used, plus an appropriate amount of thinner, can be brushed evenly, the process is simple, suitable for home decoration. Distinguish between "polyester paint" and "polyurethane paint". The easiest way to do this is: "Polyester paint" is packed with more than four components. "Polyurethane paint" is suitable for small items, including single-component and two-component. There are many two-component products on the market, that is, one is the main paint, and the other is the curing agent. The ratio and construction are relatively easy. some.
1. The diluent is a mixed organic solvent prepared by cyclohexanone, butyl acetate and anhydrous xylene.
2. The diluent is xylene, but acetone can also be used as a diluent. The dilution ratio is 1:1.5. But there are also materials that say 1:2 or even 1:4.
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