Solvent based three proofing paint
Solvent based three proofing paint is a kind of electronic three proofing paint which takes organic solvent as dispersion medium. First of all, from the performance comparison, solvent based three proofing paint still has a great advantage. Three anti paint solvents mainly include three categories of products, the first category is hydrocarbon solvent, which is classified according to different boiling points; the second category is also the most widely used and most mainstream one, which is oxygenated solvent; the third category is the most unique solvent water.
Types of solvents
Hydrocarbon solvent: it is usually a mixture of different molecular weight materials, and is classified by different boiling points, including aliphatic hydrocarbon, aromatic hydrocarbon, chlorinated hydrocarbon, terpene and other products.
Oxygenated solvent: a solvent containing oxygen atoms in a molecule. They provide a wide range of solubility and volatility. Many resins are insoluble in hydrocarbon solvents, but soluble in oxygenated solvents. Common products include alcohol, ketone, ester and alcohol ether.
Water: there are two active hydrogen ions and one electronegative oxygen molecule in the water molecule, which is different from the linear chain formed by alcohols. Water molecule combines in three-dimensional array, similar to cross-linked polymer. When water molecules combine with each other in this way, the strength of the second valence bond is greater than that of alcohols. Compared with alcohol as solvent, water as solvent needs more energy to separate molecules and combine them with other materials. This means that water is an efficient solvent for many resin materials. At the same time, it has the disadvantages of high specific energy and high boiling point. Unlike most solvents, the evaporation rate of water is greatly affected by the relative humidity of the surrounding environment and the air flow through the wet film during construction. Finally, the same unique molecular structure, which represents the low vapor pressure of water, results in high surface tension. This directly affects the wettability of the coating products and the adhesion to the substrate. This high surface energy provided by hydrogen ions makes it difficult to wet with water and obtain good adhesion bond to the substrate with low surface energy.
Characteristics of solvent based three proofing paint
1) Coating quality:
In the case of high decorative requirements, the fullness of water-based three proofing paint usually can not meet the requirements of people, and the high gloss requires the use of solvent based three proofing paint to achieve.
2) Adaptability to various construction environments:
In some harsh environments, the application of water-based three proofing paint may be limited; on the contrary, the solvent based three proofing paint can control the solvent proportion with the change of location and climate to obtain high-quality coating.
3) Solvent based paint has a wide range of options:
Almost all kinds of resins can be dissolved in solvents, so there is a wide choice. Different resins have their own unique properties, such as polyurethane with excellent weather and chemical resistance, high gloss, wear resistance, etc. silicone resin with excellent heat resistance can be used as the base material of heat-resistant and weather resistant coating.
4) Cleaning problem:
Solvent based three proofing paint construction tools must be cleaned with solvent, which is harmful to human body and environment.
Solventless three proofing paint
Solventless coatings, also known as active solvent coatings, means that the solvent eventually becomes a component of the coating film of the three proofing paint, and VOCs (volatile organic compounds) are not discharged into the atmosphere during the curing process.
Characteristics of solventless three proofing paint 1. Product environmental protection, safety and health
Because the three proofing paint is solvent-free and is composed of 100% solids, it is considered as environmental protection paint when VOC is zero. It does not contain volatile and flammable dangerous solvents, so it can be operated safely even in closed environment or poor ventilation.
2. Construction convenience
The reaction rate of solventless three proofing paint is relatively fast, and it can be sprayed repeatedly in a short time, so as to meet the requirements of different film thickness (up to several millimeter thick film). It is especially suitable for products requiring thick film type, which can be called convenience.
3. Chemical resistance and acid and alkali resistance
At present, the components of solvent-free three proofing paint, a and B, also have a single component, which can be changed in selection, so it can meet the special needs of different chemical resistance and acid-base resistance. However, due to the different composition and structure of the main agent resin in different systems of the three proofing paint, it should be selected according to its own needs.
4. Excellent physical properties
Solventless three proofing paint does not contain solvent, so there will be no bad solvent residue and affect the physical properties. Because of the homogeneity of the reaction, excellent physical properties can be obtained when the raw materials are measured correctly and are not affected by the external environment. Because the reaction degree of the resin is very complete, and its molecular arrangement is very complete. Among them, wear resistance, water permeability resistance, weather resistance and mechanical and physical properties can better show its excellent performance, such as Qingshan new material tis-nm single component solvent-free silicone three proofing paint, which has excellent performance in moisture resistance and high temperature resistance.
5. Construction operability
The solventless three proofing paint can be basically operated at room temperature without any heating equipment. At the same time, because of the short reaction time, it can be directly constructed on site, so it is very convenient in use. Because of the low impact of climate, it can be constructed in humid environment or low temperature climate. Spray can be continuous without any joints, to ensure the quality of the film.
Spraying requirements of solventless three proofing paint
Generally speaking, the solventless three proofing paint does not contain any solvent, and its viscosity is high (you can check the viscosity parameters of the three proofing paint for selection), so you need a heatable, high-pressure mixing airless spraying machine. Theoretically, the gun head temperature of spraying machine is 55-65 ℃, which can control the viscosity and reactivity of raw materials. The pressure of the equipment must be more than 2500pa (according to the raw material formula), so as to achieve the best spraying effect (of course, it is also necessary to cooperate with the selection of the gun head, discharge volume, rate, etc.). The selection of spray gun head is also very important. The equipment must keep the temperature of the gun head up to about 60 ℃. It is necessary to spray and mix the gun head mechanically and ensure that the gun head is not blocked.