Silver grain is mainly caused by incomplete drying of raw materials, caused by moisture or volatile components (mainly caused by moisture, decomposition gas, solvent gas, air interference). When producing silver filaments, the molding experiment should first be carried out with thoroughly dried pellets. If this is not possible, other causes can be checked.
The specific reasons for the production of silver wire are as follows:
1. Injection molding machine
(1) The barrel, the screw wears or the rubber head and the apron have a dead angle of the material, which is decomposed by heat for a long time.
(2) If the heating system is out of control, causing the temperature to be too high and decomposed, check whether there are any problems with the heating elements such as thermocouples and heating coils. Improper screw design results in improper venting or easy introduction of air.
2. Plastic aspect
(1) The plastic has a large humidity, and the proportion of the added recycled materials is too large or contains harmful scraps (the scraps are easily decomposed), and the plastic should be sufficiently dried and the scraps should be eliminated.
(2) Moisture absorption from the atmosphere or moisture absorption from the colorant, and the coloring agent should also be dried. It is preferable to install a dryer on the machine.
(3) The amount of lubricant, stabilizer, etc. added to the plastic is excessive or unevenly mixed, or the plastic itself has a volatile solvent. Decomposition occurs when the mixed plastic is difficult to maintain heat.
(4) The plastic is contaminated and mixed with other plastics.