The formula design of plastic profile extrusion generally follows the following principles:
(1) Fully understand the performance requirements of profiled materials: fully understand the performance indicators required by profiled materials, and should meet the highest standards required by users as the basis; understand the use environment of profiled materials such as climate, temperature and humidity, wind pressure, noise and ultraviolet rays Specific conditions, such as the purpose of use such as doors and windows or other uses such as shelves, and problems that may arise during use; understand market information, consumer interests and sales trends.
(2) Pay attention to the choice of raw materials: pay attention to the role and nature of the raw materials and the mutual influence of various additives when they are combined, and give play to the synergy between the raw materials to obtain the best effect. The general user likes the local raw materials, so use the same equipment. To produce profiles with the same properties due to the difference in the quality of raw materials, the formula design is very different; pay attention to the quality of raw materials and inspection; pay attention to the relationship between the amount of related raw materials and the performance of the profile and the extrusion process; pay attention to the price of raw materials and maintain the raw material supply channels Stability and cost reduction.
(3) Have an in-depth understanding of the extrusion equipment and production conditions. Pay attention to the whole process research of the heating behavior of the material in the extrusion equipment; pay attention to the influence of the residence time of the material in the extrusion equipment; understand the structural characteristics of the head and die and the material The relationship between rheological behavior. Only on this basis can we grasp the essence of formula design and provide practical guidance and theoretical basis for scientific and effective adjustment of formula.
Formulation design is a process of repeated practice and understanding. It is a science with strong practicality and the accumulation of experience that pays more attention to the combination of theory and practice, but it also follows its unique objective laws. At present, the amount of resin and various additives in the formulation is often expressed in weight percentage. Generally, the amount of resin is 100 (parts by weight), and other additives are expressed as a few percent of the weight of the resin.
After the formula is designed, the material compounding in accordance with the requirements of the formula is also the most important step. Different formulations have different process requirements for the mixing, mainly in the order of feeding, hot mixing temperature, cold mixing (discharge) temperature and other requirements. The processing of plastic profiles has extremely high requirements for the uniformity of the mixing, the more uniform the better it is good. This requirement is determined by the characteristics of the extrusion processing equipment.