1.Requirements of color masterbatch for film industry
Safety: Meet relevant food hygiene regulations (EU or FDA or GB9685 ……)
Dispersibility: smooth printing surface coverage – high concentration
Hue: bright, stable color control (L a, b value control)
Thermal stability: meet the high temperature continuous processing requirements
Mechanical properties: to meet the product application requirements How to choose the masterbatch
2.Factors to be concerned about when choosing color masterbatch
(1) Safety of color masterbatch
(2) Type and content of TiO in the masterbatch
(3) Type and content of additives in the masterbatch
(4) Whether the viscosity of the masterbatch matches the raw material system
(5) The content of low molecular volatiles in the processing temperature zone of the masterbatch (high temperature resistance)
(6) Dispersibility of the masterbatch
(7) Stability of color using masterbatch
3.Precautions for using color masterbatch in the processing of blown film cast
(1) Fix the ratio of masterbatch and raw material: different ratio of masterbatch will affect the color and coverage rate;
(2) Fixed production process: the change of process parameters needs to be evaluated, otherwise it will affect the product quality;
(3) Fixed mixing time: the specific gravity and particle shape of masterbatch and raw materials are different, so if the mixing time is not fixed, it will lead to uneven distribution or delamination of masterbatch in the mixing cylinder;
(4) Prevent static electricity: Static electricity is generated by friction during the mixing process, which leads to uneven distribution of plastic;
(5) Stopping in the middle of the process: the raw material should be emptied from the barrel and the temperature of the barrel should be reduced to avoid the oxidation and decomposition of the raw material for a long time, which will cause the film to turn yellow and produce black spots;
(6) selection of materials: try not to choose raw materials containing BHT antioxidants, because hindered phenol antioxidants in high temperature, high humidity, the presence of oxides in the alkaline environment, prone to automatic oxidation reaction will lead to discoloration of the surface of the finished plastic (generally become pink or light yellow);
(7) Storage: Please store the color masterbatch in a dry, ventilated and clean environment with the ambient temperature below 50℃ to avoid pollution. It is necessary to use battery car in the warehouse, because there are a lot of oxides (NOx, SOx) in the car exhaust, which will accelerate the oxidation of BHT-type antioxidants in plastic, leading to film discoloration, and there will be obvious color difference in the finished plastic bags biodegradable bags after bag cutting.
Biodegradable bags have particularly high requirements for color masterbatches. Many companies do not pay attention to the quality of color masterbatches, resulting in poor product quality. Once the color masterbatches of biodegradable bags are not good, it will affect printing.If you are doing biodegradable bags, be sure to pay attention to this factor.
