Rheological AIDS provide a leveling effect under high shear conditions, allowing the painted fluid to level out as quickly as possible, reducing brush marks and avoiding spatter. However, as the drying time goes by, this leveling effect weakens and the film is fixed, which can prevent the fluid from sagging on the vertical surface. Rheological additives can be divided into high, medium and low shear viscosity types: low shear viscosity rheological additives can provide viscosity inside the tank, prevent pigment settling, and effectively control the paint liquid in the standing Snails generated during surface operations; rheological additives that provide medium to high shear viscosity can improve the fullness and leveling of waterborne wood coatings, while rheological additives that increase high shear viscosity help leveling, Prevent splashing and improve roller and brush application performance.Therefore, the type and amount of rheological additives must be selected according to the requirements and system of the construction. Generally, the type of rheological additive is selected according to the different construction methods, and is often matched by three rheological additives of shear viscosity. In order to achieve the required construction results. Polyurethane associative thickeners are currently the most widely used in waterborne wood coatings, but the choice of such thickeners in aqueous wood coating systems is closely related to the other ingredients in the formulation.For example, the thickening effect has a great relationship with the polymer particle size and hydrophobicity and the cosolvent in the waterborne wood coating. If the polymer particles in the waterborne wood coating are smaller, the more hydrophobic, and the distribution of the cosolvent in the polymer. The higher the coefficient, the higher the thickening efficiency, otherwise a large amount of such thickeners do not reach the desired viscosity.At the same time, it is recommended to dilute with water and add it under reasonable shearing force. Otherwise, it may also flocculate with the system to produce particles. Sinograce Chemical produces water based additives, such as thickener, crosslinking agent, wetting agent.

Variety Feature Application Traditional surfactants (mainly anionic or nonionic) Poor water resistance Easy to foam and stabilize foam cheap price Putty and low-grade system · Fluorocarbon polymer Efficient Reduce static surface tension Good effect on contaminated substrates Easy to cause surface problems Not easy to control High price Very difficult to attach substrates And contaminated substrates PSAMS Wetting effect、Good resistance to foaming, shrinkage and water resistance Wide adaptability Common application Non-silicon non-fluorine Minimize possible defects Minimize possible defects Low water sensitivity Low foaming Good dynamic effect expensive All kinds of coating The ideal wetting agent should contain the following aspects: 1. Effectively reduce the surface tension of the system and improve its wettability and permeability to the substrate. 2. Foaming and foam stabilization as low as possible. 3. As low a water sensitivity as possible. 4. Does not affect interlayer adhesion 5. A good balance of surface tension can improve the wetting of the substrate without affecting the leveling or defects due to excessive reduction of surface tension. Generally, the dosage of levelling agent is 0.1%~1.0%, and it is better to control it at 0.3%. When the defoaming agent exceeds the quantity, in order to overcome shrinkage cavity, the dosage of levelling agent can even exceed 1% in the putty formula without levelling agent . Sinograce Chemical produces water based additives, such as thickener, crosslinking agent, wetting agent.

Formulation design system for water based coatings - wetting leveling agent The wetting leveling agent can effectively reduce the surface tension of the system and significantly improve the construction effect of the waterborne wood lacquer.After the addition of the wetting leveling agent, the wetting property and permeability of the paint increase, the leveling property of the paint liquid is improved, and sometimes the shrinkage (frame effect) problem can be overcome.More importantly, the leveling agent can solve the common shrinkage cavity problem, especially the shrinkage cavity caused by excessive use of the defoaming agent.Excessive leveling agent will offset the defoaming effect of the defoaming agent, so that the paint liquid will generate bubbles during construction, and some will have obvious foam stabilization effect. Therefore, it should be used with good leveling property, low foaming property and stable foaming. Small wet wetting leveling agent.The combination of leveling agent and defoamer, including the selection of varieties and the control of dosage, is the focus of research on waterborne wood lacquer formulations.

Types of defoaming agents Character Application Mineral oil Strong anti-bubble ability Low price Poor system compatibility Easy migration Primer Matte Organic silicon class Strong defoaming ability higher price Different product performance differences Large adjustment space Improper selection can cause film defects Influence gloss, flow equality Various coatings Non-silicone non-oil Good security Low probability of defects Does not affect the gloss But the amount is slightly larger Insufficient bubble breaking ability higher cost Various types of coatings, especially in high gloss finishes There are many defoamers on the market, and the choices are very cautious and can be noted in several ways: 1. Controlled compatibility, that is, to achieve the balance between defoaming and surface effects, both defoaming and prevention of defects such as shrinkage cavities and poor leveling. 2. Defoaming according to the construction conditions and methods, such as brushing, spraying and roller coating, face different degrees of foaming, and also means different defoaming agents. 3. The balance between foam suppression and foam breaking can be reasonably matched according to different processing and construction methods. 4. Long-term defoaming performance. Many defoamers will gradually reduce their defoaming performance during storage of the paint, and the antifoaming agent content in the paint should be higher when designing the formula. The amount of defoaming agent is 0.05% to 0.5% of the whole formulation, preferably about 0.1%. If the defoaming agent used exceeds 0.5% to have a good defoaming effect, the defoaming agent should be considered.Different resin systems are sensitive to defoamers. The type and amount of aqueous defoamer selected must be determined experimentally, depending on the system.