Classification, characteristics and formulation of water-based wood coatings.

Water-based coatings, english for waterbornes or waterbased coatings, also known as water-based coatings.
water-based coatings for wood coating have a variety of classification methods, commonly named according to appearance, use, construction and curing methods, emulsion type, chemical structure and equipment methods.
most important components of water-based wood paint are the emulsion and the type of resin that make up the emulsion, and the scientific method is to classify the emulsion according to its

. According to the chemical structure, water-based wood paint can be divided into:
-water-based acrylic coatings
water-based polyurethane coatings
water-based aleate paints
water-based epoxy coatings
Sol one gel coating
. . . water-based photo-curing coating
1, water-based acrylic coating
acrylic water-based wood paint is an early application and is still in a large number of applications of varieties. Since the 1970s, acrylic building latex paint began to spread widely, water-based acrylic wood paint has also appeared on the market.
acrylic emulsion is made up of acrylic monosome-based vinyl monosomes polymerized by emulsions. Various additives such as emulsifying agents, stabilizers and pH regulators have been added to the polymerization process, and the system is quite complex. Using different monomers, adjusting dosage, and changing the feeding method can control the distribution of the polymer molecules in the emulsion particles, so as to obtain different glassy temperature (Tg or different minimum film temperature (MFFT) emulsion. The emulsifying agent used in polymerization may be anion-type, or non-ionic or cation-type, the corresponding emulsion and the paint made can also be called anion-type, non-ionic or cation-type.
is only polymerized with acrylic monotones to obtain a pure propylene emulsion, made of paint called pure propylene water-based paint. Other vinyl monosomes can be added to the polymerization to modifie the emulsion, for example, add styrene to improve the hardness of the paint film and reduce costs, introduce fluorine-containing, silicon-containing monosomes to improve the surface performance of the paint film, reduce the surface free energy of the film, improve hydrophobicity and anti-stain resistance. Resulting in phenylpropanine water-based paint, fluorocarbon water-based paint, silicon propylene water-based paint and other varieties.
made of acrylic emulsion has good weather resistance, not easy to yellow, high hardness, good gloss. But its main disadvantage is poor anti-adhesion, easy to appear hot sticky cold brittle phenomenon, hard through the high and low temperature film-forming is not good, winter difficult to carry out coating construction. The properties of acrylic emulsions are further improved and improved by the techniques of self-interlinking polymerization, soap-free polymerization and nuclear shell polymerization, especially the use of nuclear shell technology, the structure of emulsion particles into hard-core soft-shell or soft-core hard shells, and even multi-layered structures of soft and hard questions, to meet the needs of different construction and use conditions.
2, water-based polyurethane coating
polyurethane is a class of large molecular compounds in molecular structure with urethane structure, usually made of isocyanate and polyol by polygame reaction. Due to the diversity of isocyanate and polyol species, polyurethanes can be obtained from soft to hard, from brittle to tough, from high elasticity to a certain rigidity of various forms of products. Polyurethane coatings also have a wide range of performance adjustments.
according to the type of isocyanate used in the preparation of polyurethane, polyurethane emulsion and the corresponding paint can be divided into two categories: fat family type and aromatic family type. The paint film of the fat family has excellent weather resistance and yellow degeneration and can be used as an outdoor decorative coating; Polyols used are polyether polyols, polyester polyols, polyolefin polyols, etc., resulting in polyether polyurethane water-based coatings, polyester polyurethane water-based coatings and other titles.
hydro-based groups or hydro-water chain segments must be introduced in the process of synthesization of water-based polyurethanes. The most common hydrophobic groups are anionic niobium and sulfonate- and large-molecule main and side chains can also have cation groups like seasonal ammonium ions, or the introduction of non-ionized polyoxyethylene long-chain segments and hydrohydroxymethyl hydroxymethyl hydroxymethyl hydroxymethyl hydroxyl hydroxyl hydroxyl hydroxyl hydroponics, the corresponding water-based polyurethane is called anion, cation and non-ionic type.
The resulting particle sizes are polyurethane emulsions and polyurethane dispersions (PUDs), which usually have nanoscale particle sizes, are translucent and even completely transparent in appearance, and are one of the best water-based wood lacquer substrates available, especially called nano-emulsions, to distinguish them from ordinary white emulsions.
water-based polyurethane film has excellent flexibility, often mixed with relatively rigid acrylic emulsion paint, the resulting water-based wood paint has both advantages, especially in the lower temperature can be filmed, and better paint film hardness. A better approach is to introduce acrylic monomers into the preparation of polyurethane dispersions to form nuclear shell structure particles with polyacrylates as cores and polyurethanes as shells. This polyurethane monopropylene dispersion (PUA) is considered to be the fourth generation polyurethane dispersion, specifically known as hybrid, its performance is better than acrylic emulsion and polyurethane dispersion mix, mainly in the paint more stable, lower temperature film-forming better, non-sticky, high hardness, flexibility, good adhesion, etc., has been widely used.
3, water-based alicic acid paint
vegetable oil after alcoholation and acid reaction to produce aolic acid resin, increase the content of hydro-hydrogenic groups can be made into water-soluble or water-dispersable resin, water-soluble hydroolic acid appearance is quite transparent, but color, and aolic acid emulsion is brownish opaque. Unsaturated bonds in aolic acid resin molecules are the basic guarantee of excellent performance of paint film. As with solvent-based alcoholic acid, the performance of the coating can be adjusted by the length of oil, short oil, fast drying, high gloss, paint film hardness, long oil, good flexibility of the paint film, good impact resistance. Therefore, water-like alcoholic acid also has a short oil and long oil degree.
acid resin has good permeability in wood and is particularly suitable for the manufacture of water-based colorants. Another great advantage of water-based alcoholic acid is the use of oxygen cross-curing in the air, so the solvent resistance of the paint film is much better than other single-group water-based paint. Acrylic modified water-based alcoholic acid is in the synthesis of alcoholic acid in the molecule into the acrylic monosome, modified alicic acid resin preservation has been significantly improved. Recently, in order to further improve the performance of water-based aliclicic acid paint, the development of aliclicic acid /acrylic hybrid technology, to make aolic acid polymer for the nucleo, acrylic polymer shell system, hydrophobic acrylic shell to protect the alicic acid nucleation is not hydrolysed. The water in the paint is evaporated, the emulsion fine particles seep into the wood micropores, and the wired polymer molecules are then oxidized into a membrane.
water-based ammonia oil is a modified aolic acid resin with isocyanate. The hydroxyl reaction of isocyanate and acetic acid resin produces polyurethane structure, which has the performance of some polyurethanes, while retaining the properties of oxidation crosslinking of acetic acid resin, thus making the single-part water-based paint construction convenient, excellent performance, is one of the excellent varieties of water-based paint.
4, sol/gel coatings
Sol-Gel coatings are new coatings that have received special attention in recent years. The progress of inororous nano-powder has promoted the development of sol-to-gel coatings.
main components of a gel coating are organic resins and silane compounds, which hydrolyze to produce the sol, which is then reduced to a gel on a solid surface. The active group in silane reacts easily with inorganic materials such as organic resins or silicon dioxide sol, and silane itself can shrink into large molecules of mesh structures, resulting in a paint film with high hardness, scratch resistance, solvent resistance and water resistance. The solvents in the coating are mainly organic solvents such as isopropyl alcohol, containing a small amount of water, strictly speaking, not the true sense of water-based coatings, but environmentally friendly coatings. The newly emerging sol-gel coating for wood paint is a promising new variety of wood coating.
5, water-based photo-curing coatings
water-based photo-curing coatings are classified according to the curing method of a class of coatings, is an important type of coatings. Any polymer molecule that introduces an active group that can be decomposed by a light trigger, or a structure that can be stimulated by high-energy radiation to produce an active group, can be made into a photo-cured coating or a radiation-cured coating.
are ultraviolet (uV) curing coatings, visible light curing coatings, and electron (EB) beam curing coatings, most commonly UV curing methods, according to the light source required for curing. Photo-curing coating has a highly interlinked structure, solvent resistance, scratch resistance is very good, paint film hardness is very high, as a water-based floor coating is the most widely used, of course, can also be used to do water-based furniture paint, water-based cabinet paint and water-based board wall paint.
water-based coating formulation design principles
water-based coatings, including water-based wood paint is water-based dispersion medium and thinner coatings. Unlike commonly used solvent-based coatings, the formulation system is a more complex one. When formulating, we should pay attention not only to the type of polymer, emulsion and the performance of dispersion. There is also a need for a reasonable selection of additives and a reasonable match taking into account the interaction between the ingredients. Sometimes special additives are selected for special requirements, resulting in an applicable formula.
the basic composition and action of water-based wood paint
⊙ polymer emulsion or dispersion: this is the substing of the film, determines the main function of the lacquer film.
⊙ film additives: after water evaporation, so that emulsions or dispersive particles form a uniform dense membrane, and improve the film-forming under low temperature conditions.
⊙ anti-foaming agents and de-foaming agents: inhibit the bubbles produced in the lacquer liquid during the production process and allow the resulting bubbles to escape from the surface and break the bubbles.
⊙ wetting leveling agent: improve the wetting performance of lacquer liquid on the substrate, improve the leveling, increase the adhesion of the paint film to the substrate.
⊙ the paint: to provide good fluidity and leveling of paint materials, reduce the ills in the coating process.
⊙ control aids: improves the performance of the coating film.
⊙ anti-lighting agent: regulate the water-like wood coating film gloss.
⊙ preservatives: prevent mold in the storage process.
⊙ pH regulator: adjust the pH of the lacquer liquid to stabilize the lacquer liquid.
⊙ special additives for colorants
⊙ fillers
in addition, small amounts of deionized water are often added to the formulation for painting.water-based coating design system - substitlysis
water-based wood paint formulation, the substation is the formation of lacquer film and determine the paint film performance of the key ingredients. The base material, i.e. polymer emulsion, dispersion or hybrid, accounts for more than 80%, preferably more than 90%. Due to the low solid content of the emulsion, especially the water dispersion (water dispersion is generally 30% to 35%), the formulation should be designed to maximize the amount of the base material, so that the effective film content in the lacquer liquid as much as possible, so as to ensure that the paint made of a coated paint film thicker, high plumpness.
polymer emulsions are generally higher than the solids of water dispersions. The water-based base solids increase their viscosity so quickly that they can be thickened to the point where they cannot be painted smoothly. The particles in the water dispersion area are small, so this phenomenon is more significant, usually only to make a concentration of less than 35%. Because the emulsion particles are relatively large, the same solids under the viscosity is smaller, generally can be made into about 50% of the solid parts. This difference should be taken into account in formulation design, i.e. when using water dispersion system paint, the amount of dispersion should be increased as much as possible.
type of emulsion or water dispersion to be selected depends on the purpose of the use of water-based wood paint. Outdoor water-based wood paint climate aging conditions are harsh, should give priority to the use of adipose polyurethane dispersion or acrylic emulsion. Indoor paint can be used aromatic polyurethane dispersion or acrylic emulsion, glucification temperature is high or curing process can be cross-linked to improve water resistance, iron resistance.
Water-like wood paint solid paint has some pigments and fillers, emulsion or water dispersion of the amount of corresponding to reduce, generally in 70% to 80%, and putty fillers more, emulsion or dispersion of the amount can even be as low as about 50%.
has been successfully applied to water-based wood coating resin types are mainly water-based alcoholic acid, acrylic emulsion or dispersion, water-based polyurethane dispersion and water-based acrylic polyurethane dispersion.
water-based coating formulation design system - preservatives
water-based wood coating is a water-based system, in the production process is easier to bring in bacteria, in the storage process are more easily degraded by microorganisms, therefore, in the formulation design should be appropriately added preservative type and dosage, to prevent the system and coating corruption. From the point of view of environmental protection, we should use lower toxic preservatives, but also pay attention to the matching with the system, and must be diluted with water when added, otherwise, flocculation and adverse phenomena will occur with the system.
generally speaking, the amount of preservatives used in 0.1% is sufficient to prevent mold in the storage process. With 0.1% preservatives, sealed storage for two or three years is not a problem.
water-based coating formulation design system - pH regulators
water-based wood coatings may also need to adjust pH when necessary. Most emulsions or water dispersions have been produced with a pH of 8 to 9, and pH regulators are no longer required for painting. If the pH deviation in the process of painting to add 0.05% to 0.1% of the pH regulator, the pH of the paint liquid to 7 to 9. Many water-based wood paints can only be stabilized under neutral to slightly alkaline conditions, when the pH is too high or too low, the lacquer liquid may produce flocculation, precipitation, re-coarseness, deterioration of construction performance and other phenomena.
the pH requirements of different systems are different, so the pH of water-based wood coatings is adjusted according to the different systems, taking into account the matching of preservatives in the formulation. It is also important to note that water must be diluted in multiply when added to avoid causing particles to be produced by the system.
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