At present, "masterbatch" (also called masterbatch or masterbatch) is widely used for plastic coloring. "Masterbatch" is made by mixing fluorescent whitening agent or pigment with the required resin plastic in advance, and directly melting and extruding it. The resulting colorant products containing Optical Brighteners or pigments with a relatively high concentration can be used directly and have become a major means of coloring plastics.
Why should we add fluorescent whitening agent to the masterbatch? The white masterbatch formula in the color masterbatch often turns yellow. The incident reflectivity of titanium dioxide is less than 100%, especially the blue and purple spectrum wave ends, and the light absorption rate is very high. Therefore, it is not pure white, but has a light yellow tint. The fluorescent whitening agent can absorb ultraviolet light (wavelength 300-400nm), and then emit purple fluorescence (wavelength 420-480nm), so it can significantly improve the whiteness and gloss. However, the mechanism of Optical Brighteners and blue-added whitening are different. The former lies in "adding light", while the latter lies in "reducing light". When the light is added strongly, the reflectivity can greatly exceed 100%. In the past, people believed that objects that can reflect 100% of the incoming light should be the whitest. Therefore, after the advent of Optical Brighteners, people obtained the so-called whiter than white. From the perspective of people's visual consciousness, the bluish tint is more White with a yellow tint makes it appear whiter.
Since the amount of masterbatch fluorescent whitening agent is very small, the masterbatch used only needs to be accurately measured. When using, a certain amount of it is mixed into the material before plastic molding to achieve the purpose of coloring and whitening, which is quite convenient. It also reduces dust and greatly improves the working environment. It is loved by many manufacturers and currently has optical brightener masterbatch products supplied to the market. Plastics colored by this method include polyvinyl chloride, polyethylene, polypropylene, etc. Generally, injection molding, extruded tubes, extruded films, wire coatings, hollow molded products or sheets with mixing equipment are suitable for coloring with masterbatch.
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