For processing plastic profiles, a hard resin with a polymerization degree of 1000 (SG5 type) and a K value between 66 and 68 is generally used. Although the grades and production processes of resin suppliers are different, the resin selection of general profile manufacturers is fixed and will not be changed at will. However, the resin produced by the acetylene method has batch instability factors. If it is selected, it is best to use the same batch.
Moreover, the colorant is composed of a carrier, a colorant and an additive. The colorant and PVC resin have a certain degree of incompatibility. Therefore, the carrier of the colorant should be of the same type as the resin to be colored. vice versa.
2. PVC Stabilizer.
Stabilizers have a positive effect on the light fastness and weather resistance of plastic products. Stabilizers are divided into heat stabilizers and light stabilizers. In the same way, not only such additives should be added to the profile formulation, but also the colorant itself, and it is best to be consistent with the model, batch, and manufacturer in the profile formulation.
Antioxidants have a good protective effect on the color of polymers. Generally, the combination of main and auxiliary antioxidants has excellent thermal stability and antioxidant properties. At present, the best application in the plastics industry is 1010 produced by Swiss Ciba. Generally, it can be used in conjunction with ETHAPHOS368, BTHANOX310 or DLTP to play a synergistic effect.
4. Ultraviolet absorbent.
Adding an ultraviolet absorber to the polymer can reduce the damage of sunlight to the polymer resin, but this damage cannot be completely avoided. Experiments have shown that the addition of UV absorbers cannot protect the surface of the polymer because it first acts inside the polymer, so the purpose of adding UV absorbers is to deactivate the free radicals before the polymer chain reaction begins. Commonly used models are UV-9, UV-531, UV-35, UV-327, etc., and UV-531 is more commonly used in plastic profiles. And the combination of ultraviolet absorber and hindered amine (HALS) has a chemical synergistic effect.
The choice of lubricant in the formula is also very critical. A good lubricant will give the plastic profile a high-quality finish. Oxidized polyethylene wax, PE, OPE, EBS, etc. are generally used. Try not to use paraffin wax. Severe precipitation during paraffin extrusion will shorten the mold cleaning time and affect the finish of the product. In severe cases, it will directly affect the physical properties of the profile.
6. Other matters needing attention
During the processing of plastic profiles, resins and colorants will generate static electricity when flowing in the powder state. The addition of antistatic agents can avoid the bridging phenomenon caused by static electricity during the transportation and feeding of powder materials.
When adding the colorant to the formula to produce the same full-color plastic profile, the profile of the profile remains unchanged, and the switching of any auxiliary agent will affect the color, especially the color difference of the profile products caused by the switching of the stabilizer or calcium carbonate is very large .