The composition and selection principle of can wall coating
Paint is an organic compound. The raw materials of the paint are the following: oil, resin, pigment, plasticizer, diluent and other auxiliary materials. Oil and resin is the main film coating material, but also the basis of paint, pigments and plasticizers are secondary film material. Many types of oil, in the paint industry is commonly used in linseed oil, tung oil, cottonseed oil and sesame oil and so on. Resin is an important part of the composition of paint, is a complex polymer compounds, can be solid state, can also be high viscosity colloidal state. The resin solution will be coated on the surface of the object, the solvent can be cured after the resin can be cured film, with resin coating can improve the coating film hardness and chemical resistance. Generally, most of the paint in the tank is made of resin as the main component.
Many types of resin, according to its source can be divided into two major categories of natural resin and synthetic resin. Synthetic resin, also known as synthetic resin, such as epoxy resin, phenolic resin, and polyethylene resin. Before the successful development of synthetic resin, natural resin in the paint industry is widely used, but its quality is unstable, subject to regional restrictions, the use of inconvenient. The use of synthetic resin after not only improve production, but also easy to control the quality. A wide range of synthetic resins are used throughout the world to produce coatings, including canned coatings. Most pigments are powdery solids that are insoluble in water and oil, some of which are natural minerals, and many are synthetic organic or inorganic compounds. Empty tank coatings rarely use pigments, but add a small amount of zinc oxide to the anti-sulfur coating. The solvent is also part of the coating, which dissolves and dilutes the resin and the coating, changing its viscosity for coating. The solvent is a volatile liquid that evaporates all during the drying of the paint and should not leave a nonvolatile residue in the coating film. Although there is no solvent in the coating film, the solvent and coating film formation and quality are closely related. If the solvent is used improperly, the quality will be greatly affected. It is very important to choose the solvent correctly in the production of the coating iron. It is best to take into account the different conditions of the coating, the specific conditions of the processing, the workshop equipment and so on. To ensure product quality. China since the sixties of last century began to develop canned food coatings, since the early 70s, stopped the import of paint iron.
What are the benefits of the inner wall coating for canned storage?
Canned paint generally divided into four kinds: the inner wall coating; outer wall paint; seams fill paint; all spray coating.
Outside the wall to remove the rust to prevent rust and safety and health requirements outside the point of contact, the other functional role we are not here to explore.
And the other three kinds are in close contact with the contents of the canned food: the coating after the film is not toxic, do not pollute the contents; better adhesion; after a certain temperature sterilization, the coating does not soften, fall off, dissolved; For different products, different sterilization temperature, the choice of paint requirements are different.
Commonly used canned wall paint and color, the principle of selection
Various coatings have their own characteristics and applicability. Different types of food, paint and coating iron requirements are also different. According to the use of large governance with anti-sulfur coatings, acid-resistant paint, anti-stick coating, paint cans and foreign printing iron coating.
Commonly used canned wall paint and color, the principle of selection:
1. Acid-resistant paint: commonly used is 214 epoxy phenolic resin coating, mainly for acid cans. 214 golden yellow.
2. Anti-sulfur coating: commonly used is 214 epoxy phenolic resin coating, mainly for animal cans. 214 golden yellow. That is 214 is anti-acid, anti-sulfur dual-use coating. With anti-hydrogen sulfide permeability.
3. Pouring the tank paint: for washing cans, aquatic products, golden yellow.
4. Stripping (anti-stick) paint: to solve luncheon meat and other meat products sticky cans. Pale white.
5. Seal fill coating: Seam coating due to welding heat damage, so to make up. Most golden yellow. Paint, but caused by corrosion, causing container trade disputes. Such as Gongjing factory.
6. Other special coatings: such as mushrooms 510 paint.