Nitrocellulose paint (code Q) is nitrocellulose paint, commonly known as "spray paint". Its main raw material is nitrocellulose , also known as nitrocellulose, which is made of cotton fiber or cottonseed linter fiber nitrated by nitric acid and sulfuric acid . The nitrogen content of nitrocellulose for paint is about 12% (nitrogen content of 12.5% ~ 14% is used for smokeless powder , and 10% ~ 11% is used for celluloid). Nitro lacquer is prepared by dissolving nitrocellulose, synthetic resin and plasticizer in a mixed solvent. The synthetic resin used is divided into hard resin and soft resin. Hard resins such as rosin acid glyceride resin, rosin modified maleic anhydride resin, etc., which make the coating film glossy, increase , and have good polishing performance; soft resins such as modified alkyd resin, amino resin, epoxy resin, etc. Resins, acrylic resins, etc., these resins can significantly improve the weather resistance, mechanical properties and gloss of the coating film.
Plasticizer is another important component in lacquer, which can improve the flexibility and adhesion of the paint film and reduce the permeability. Plasticizers can be divided into two types: solvent type and non-solvent type: solvent type includes dibutyl phthalate , dioctyl phthalate, dioctyl phosphate, etc.; non-solvent type plasticizers mainly include castor oil, Oxidized castor oil. Nitro paint is a volatile and drying paint, so the solvent composition in the formula directly affects the solvency . Solvents for nitro lacquer include:
①True solvents, such as butyl acetate, ethyl acetate, acetone.
② Co-solvents, such as butanol and ethanol. Co-solvents do not dissolve nitrocellulose by themselves, but their addition can increase the solubility of true solvents for nitrocellulose.
③ Thinner : such as toluene, petroleum hydrocarbons. The diluent does not dissolve the nitrocellulose, but only dilutes it and reduces the cost of the solvent .
Nitro paint is characterized by rapid drying, which can be surface-dried within ten minutes after construction, which can shorten the working hours, and the paint film is hard and wear-resistant, has sufficient mechanical strength and durability, is convenient for grinding, polishing and waxing, and has a good gloss. The disadvantages are that the solid content is low, the dry film is thin, and multi-process construction is required; a large amount , causing serious pollution; and the paint film is easy to turn white when applied in a high-humidity environment. Nitro-based paint is widely used in machinery, light industrial products, electrical instruments, wooden furniture, pencils, leather, etc. It is an important category of paint products.
