Several dry methods of water-based coatings

Natural boredom has the advantage of being simple and well-used, but together it has the disadvantage of being slow and dry. Under natural conditions, temperature and humidity and wind speed change from time to time, and the dry speed and film quality are unstable. If be in high temperature high humidity or humidity is bigger below the condition, coating sends white simply, dry speed is slower. At low temperatures, boredom is slow; Especially under 5 ℃, water-based paint film. These are the important reasons for restricting the use of waterborne coatings.

Hot air boredom

Hot dry air convection principle is chosen to temperature of 40 ~ 60 ℃ hot air for heating medium, the heat transmitted to the workpiece surface coating, the coating after curing film absorption energy heating dry method. Commonly used electricity or steam as heat source, the air is heated first, the heat is transferred to the coating surface by convection method, so that the coating gets fast and dry. By using hot air dry technology, the coating can speed up the dry speed obviously, and has strong compliance, it is a kind of boring method used widely.

Microwave boring

Microwave refers to the wave length of 1mm-1m and frequency of 300mhz-300ghz with penetrating electromagnetic wave. Commonly used microwave frequency is 915-2450mhz. Microwave heating USES the principle of dielectric loss, while the dielectric constant of water is much larger than that of dry matter, and most of the energy released by the electromagnetic field is absorbed by the water painted in. The microwave field changes the direction of the applied electric field periodically at a rate of several hundred million times per second, causing the water molecules to sway rapidly, resulting in significant thermal effects, causing the interior of the coating to increase rapidly along with the surface temperature. The advantage of microwave heating is that the dry speed is particularly fast, different materials on microwave selective absorption; There is no shape appeal about being boring; The heating of the film is uniform, there is no temperature gradient, can dry thick film.

Ultraviolet boredom

On water - based UV wood coatings, UV curing can be selected dry methods. UV curing refers to the dry method of stopping curing water UV wood coatings under the UV mapping with a wavelength of 300-400nm.

In the water-based UV coating, there are a few photosensitizers. Under the ultraviolet light, the photosensitizer absorbs the ultraviolet light of a specific wavelength, synthesizes the active group, initiates the polymerization reaction of the film-forming material, and forms the reticular structure to solidify the coating. Uv curing is characterized by fast curing speed and good quality of coating. But. This method can only be used to dry water UV paint, and can only be dry flat plate - like furniture.

Infrared boring

Infrared curing can be used to dry waterborne wood coatings. The practice of infrared curing refers to that the painted furniture plate and its coating absorb radiation energy and is transformed into thermal energy under the reflection of infrared, so as to end the curing of the coating. Infrared ray is an invisible ray between visible light and microwave, with a wavelength of 0.72-1000um. By wavelength scale, can be divided into "near", "medium", "far" infrared.

The infrared curing of the common far infrared dry coating has the advantages of fast curing, rapid heating and good curing quality. However, when the dry coating is heated by infrared, the coating has a significant temperature gradient. Infrared boring can only heat the infrared light can reflect the area, can not be used to dry flat objects.