Paints Sector Raw Materials / Solvents

• Pigments and fillers, • Binders, • Chemical additives, • Solvents & water. Paint composition consists of binders, pigments, solvents and other additive materials. Pigments: Dispersed within the paint, pigments provide color while also enhancing fundamental paint properties such as opacity, consistency, durability and corrosion resistance. Binders: They transition from liquid to solid as the solvent evaporates. They influence numerous factors including drying method and duration, compatibility with other layers, durability, application properties and gloss. Examples include alkyd, acrylic, polyurethane, PVA, polyester and epoxy. Additives: They are incorporated in small quantities and improve certain properties of the paint. Solvents: Solvents adjust paint viscosity, dissolve the resin into solution and facilitate easier paint application. Solvent is a volatile material, and after application, the remaining paint is fixed to the surface. Examples include xylene, toluene, acetone, ethyl and butyl acetate. Solvent Performance Is Generally Evaluated According to the Following Parameters: • Dissolving the binder at high concentration • Ensuring this binder solution has low viscosity Solvents can be divided into two main groups: organic and inorganic. Carbon dioxide, phosphorus tribromide, ammonia and water are inorganic solvents. Solvents containing carbon are classified as organic solvents. Examples of organic solvents include alcohols, ethers, esters and amines. Hydrocarbon solvents are the most widely used solvents in the paint industry. Hydrocarbon solvents are preferred because they are cost-effective and effectively dissolve oils, alkyds, varnishes and other resins. [1] Below are the general solvent (volatile substance) contents of water and solvent-based paints: In solvent-based paint, the solvent ratio is approximately 80%. Meanwhile, the ratio in water-based paint is approximately 10%. In water-based paints, the water ratio is approximately 70%. The function of water here is not to dissolve the binder but to form an emulsion with it. Some Properties of Solvents Evaporation Rate: Solvents evaporate after paint is applied to the surface. This property significantly affects the physical and mechanical properties of the paint. As evaporation rate increases, drying speed increases and sagging decreases. A disadvantage of very rapid evaporation is brush marks. The paint does not have sufficient time to flow. Evaporation Number: The "evaporation number" is defined as the ratio of the time required for a given amount of solvent to completely evaporate at 20 °C and 65% relative humidity to the time required for the same amount of reference solvent to completely evaporate under the same conditions. Diethyl ether is commonly used as the reference solvent in Europe and Turkey. In America and the Far East, n-butyl acetate is the more widely used reference solvent. Thus, the evaporation number and evaporation rate of n-butyl acetate are taken as "1" and other solvents' values are calculated by proportional comparison. On the other hand, evaporation number is the inverse of "evaporation rate". [2] For example: Acetone's evaporation time is 2.1 times that of ether. Evaporation Number: 2.1. In other words, acetone evaporates 2.1 times slower than ether. Evaporation Rate: Acetone's evaporation rate relative to ether is 1/2.1 = 0.48. Boiling Point: The point at which vapor pressure equals atmospheric pressure. Color: Most of the solvents used are colorless, so they do not cause problems in production. Acidity: Solvents must be free of acidic substances and sulfur compounds to avoid reaction with other materials used in paint. Small quantities of sulfur-containing substances in solvents can create a corrosive effect. Odor: Each solvent has its own characteristic odor. When solvents evaporate, these odors disperse into the environment. Since they are generally harmful to health, work areas must be well ventilated. [3] Bilge Çalışkan / Product & Service Development Manager / Aleph Trade

Table 1. Average Solvent Usage Ratios in Some Paint Formulations

References [1] Gündüz, G., "Boya Bilgisi", TMMOB Kimya Mühendisleri Odası. [2] http://megep.meb.gov.tr/mte_program_modul/moduller_pdf/ Boya%20Solventleri.pdf [3] https://www.tobb.org.tr/SanayiMudurlugu/Documents/KapasiteKriterleri/ grup3521_1.pdf