What are the commonly used coating materials
xinstSep 01, 2020
Coating materials Laminating is a technology that attaches a plastic film to the surface of printed matter to protect the printed matter and increase gloss. The layer of film on the printed matter plays an important role in the quality, life and appearance of the printed matter. So what materials are generally used for the film? Below XINST will take you to learn about the commonly used materials for laminating!
1. Adhesives commonly used in laminates
Commonly used film adhesives are solvent-based, alcohol-soluble, water-soluble and solvent-free. Solvent-based adhesives have good stability, but still use a large amount of aromatic hydrocarbons and organic ester solvents, which are harmful to the health of operators and easily pollute the environment. Alcohol-soluble and water-soluble adhesives are low-toxic or even non-toxic, have great advantages, and are low in cost, but the adhesion fastness is unreasonable and the performance stability is poor.
2. Plastic film commonly used for laminating
There are many kinds of plastic films. Plastic films commonly used for laminating mainly include polyethylene film, polypropylene film, polyester film and new biaxially oriented polypropylene film, of which the most commonly used is biaxially oriented polypropylene film.
1) coating materials Polyethylene film
Polyethylene is abbreviated as PE. Polyvinyl film is usually produced by extrusion (forming) or calendering. PE film is colorless, tasteless, transparent and non-toxic. Water and chemicals will not affect it, and it is insoluble in most solvents at room temperature. Polyethylene is an inert material that is difficult to bond, so corona and other surface treatments must be carried out before coating. PE film can be divided into low density polyethylene, medium density polyethylene and high density polyethylene according to its density.
(2) coating materials Polypropylene film
Polypropylene is abbreviated as PP, and polypropylene film can be divided into blown film (IPP), non-stretched T-head flat film (CPP) and biaxially oriented film (BOPP) according to the production method, performance and use. Among them, BOPP film has excellent mechanical strength, double folding strength, toughness, air tightness, moisture barrier, cold resistance, heat resistance and transparency due to the orientation of the stretched molecules, and it is non-toxic and tasteless, and is the most widely used film. Film material.
As BOPP film is a non-polar substance, it must be corona treated before use to meet the required surface tension. The longer the storage time of BOPP film, the worse the corona treatment effect and the worse the adhesion fastness. If the time is too long, the corona treatment must be performed again.
(3) Polyester film
Polyester is abbreviated as PET, which is a kind of film material with good transparency and gloss. At the same time, it has the following characteristics: high mechanical strength, its tensile strength is about 5-10 times that of polyethylene, high stiffness and strong impact resistance; good heat resistance, melting point at 260℃, softening point at 230～240 ℃, the shrinkage is still very small at high temperature, and it has very good dimensional stability. It will not affect its performance after heating for a long time at high temperature; it has good oil resistance, good acid resistance, not easy to dissolve, and has good acid corrosion resistance. Corrosion by organic solvents and oils, but it is easily deteriorated when exposed to strong alkalis; it has good gas barrier properties and good odor barrier properties; good transparency, light transmittance above 90%; barrier performance to water vapor is not as good as polyethylene And polypropylene; poor protection against ultraviolet rays; easy to charge static electricity, static elimination treatment should be carried out before printing. The polyester film used for the film is also a biaxially stretched PET film.