Optical brightener has been playing the role of "salt" in plastic processing. The amount of ten thousandths can make the plastic products whiten and brighten, and improve the appearance of plastic. There are many ways to add brighteners, but their use methods are mainly divided into dry whitening, wet whitening and color masterbatch whitening.
Introduction of three usage methods of plastic optical brightener
1. Dry whitening
Plastic dry whitening is that a certain amount of optical brightener dry powder is directly added to the plastic substrate before plastic forming. First, it is mixed with the plastic substrate. When the extruder reaches the plastic melting temperature, the mixture is squeezed into the screw to melt, so as to make the plastic whitening agent evenly distributed in the melt. Finally, it is granulated or pressed.
Dry process Plastic whitening agent is mainly used for injection molding whitening of rigid PVC, PE, PP, ABS and other thermoplastic resins. Fluorescent brighteners used for dry whitening agents are relatively cheap, but they have the disadvantages of high dust dispersion and environmental pollution.
2. Wet whitening
In order to improve the dispersion effect of wet whitening, it is necessary to add a certain amount of adhesive to the plastic whitening agent to make the plastic whitening agent adhere to the surface of the material, so as to reduce the dust flying and pollution.
The optical brightener can also be dispersed in the auxiliary solution and added in batches in the form of auxiliary dispersion. For example, it can be used in soft polyvinyl chloride (PVC) to form 10% dioctyl phthalate plasticizer solution and then added in batches.
In wet whitening, the plastic whitening agent is a fine dispersion slurry, because there are non-volatile organic solvents mixed into the plasticizer, so it has the disadvantage of viscosity. Hony chemical generally recommends this whitening method for soft PVC.
3. Color Masterbatch whitening
At present, the use of "Color Masterbatch" has become an important means of plastic coloring. When using color masterbatch, as long as the color masterbatch and resin are evenly mixed in proportion, it can be directly used for the molding of plastic products.
A small amount of mixing only needs hand, in the case of a large amount of processing, in order to ensure the dispersion of Color Masterbatch, mechanical mixing can be used. After the color masterbatch is mechanically mixed with the resin plastic, it can be sent to the injection molding machine with the pre molding device for pre molding and coloring.
Precautions for use of plastic whitening agent
1. The addition amount of optical brightener must be well controlled. Please add it in strict accordance with the manufacturer's instructions. Do not add too much (the more the brightener, the better. Excessive amount will make the plastic yellowing).
If you can not determine the exact amount of plastic whitening agent, you can contact us, we will give detailed instructions according to your product within 3 days.
2. The whitening agent and raw materials must be stirred evenly, must be even, must be even, important things to say three times.
Here is just to introduce the use of several kinds of plastic optical brightener, which needs to be selected by terminal plastic manufacturers according to their own situation.