On the formulation design of water-based wood paint

All of our water-based interior and exterior wall coatings, metal paint, automotive paint, etc. have the corresponding water-based paint products. Visible water-based paint has been widely used in many industries. And our daily life is generally concerned about water-based wood paint, wood coating in the technical difficulty and high-tech products,

. Today, we use wood paint in water-based coatings as an example to illustrate formulation design.
water-based wood paint is a water-dispersed medium and thinner coating, unlike the commonly used solvent-based coating, its formulation system is a more complex. The formulation is designed not only to pay attention to the type of polymer, emulsion and dispersion performance, but also to select a variety of additives and take into account the interaction between the components to make a reasonable match. Sometimes special additives are selected for special requirements, resulting in suitable formulations.
The basic principles of water-based wood paint formulation design
(1) emulsion or water dispersion dosage as much as possible;
(2) additive varieties as few as possible, can not be used;
(3) most of the improper dosage of additives have side effects, so the dosage of additives as little as possible;
(4) pigmentation dosage is as good as possible, as long as the purpose can be achieved.
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wood paint formulation, the substation is the key part to form the paint film and determine the paint film performance. The base material, i.e. polymer emulsion, dispersion or hybrid, accounts for more than 80%, preferably more than 90%. Because the solid content of the emulsion, especially the water dispersion body is low (water dispersion is generally 30% to 35%), the formulation design should try to improve the amount of 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 is thicker, high fullness.
polymer emulsions are generally higher than the solids of water dispersions. Water-based solids are raised to a certain degree and the viscosity increases so quickly that they can thicken 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 the 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 used depends on the purpose of water-based wood paint. Outdoor water-based wood paint climate aging conditions are harsh, should be preferred to choose adipose polyurethane dispersion or acrylic emulsion. Indoor paint can be used aromatic polyurethane dispersion or acrylic emulsion, glucification temperature to be 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.
de-foaming agent
water-based wood paint is now generally polyurethane, acrylic and polyurethane acrylic mixing system. At present, the main push of the market or acrylic emulsion-based wood paint. However, the overall performance is worse than oily wood paint. So large enterprises use acrylic polyurethane mixture to replace, pure acrylic wood paint. With the strengthening of environmental protection, water-like paint on the product performance requirements increased. The selection of water-powered wood furniture paint additives also needs to meet the requirements of the product itself. Therefore, the role of desiccant in water-like wood paint is very important. There are many gaps in the wood, not only need to de-foam, but also need to de-bubble.
desulbant concentrate: the tendency to trigger the surface is small. Excellent de-foaming during grinding, especially recommended for pure propylene emulsions and their use in conjunction with other desobbists emulsions, suitable for gonorrhea construction.
de-foaming agent emulsion: in low to medium viscosity acrylic or acrylic/polyurethane emulsion and two-group polyurethane system can effectively eliminate micro-bubbles and large bubbles. Suitable for mixed spray construction. It is especially recommended for water-like, radiation curing systems and aolic acid emulsion systems. Can also be applied to the construction of spray coating.
pH regulator
water-based wood coating may also need to adjust pH when necessary, most emulsions or water dispersion production has been set to 8 to 9 pH, paint no longer need to use pH regulator. If the pH is biased, the pH regulator of 0.05% to 0.1% should be added to the painting process, and the pH of the lacquer liquid should be adjusted to 7 to 9. Many water-based wood paint 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, construction performance deterioration and other phenomena.
The pH requirements of different systems are not the same, therefore, the pH of water-based wood coating is adjusted according to the different systems, at the same time to consider the match with the preservatives in the formula, but also note that the addition must be diluted with water multiples, so as not to cause the system to produce particles.
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