What are the requirements of plastic container molding?
The hollow blow molding of plastic container has the following two requirements on plastic.
(1) general requirements for production technology.
The plastics used should be compatible with additives and concentrated masterbatch (thick color masterbatch, functional masterbatch) and even plasticizing.
Potassium single plastic or blending materials, its melt plasticizing is even, the surface of the billet is smooth and smooth.
In the range of molding temperature, the melt has sufficient flow capacity and thermal stability, and can be repeated when needed.
The billet is not easy to self-weight droop, and has good quality and length of repetition ability.
Even at high speed tensile billets, plastic billets should have sufficient tensile strength.
The billet has enough heat sealing strength to prevent the bottom seam from cracking when the billet is blown out or formed
The blow-molding container made by utilizing the tool can be reprocessed.Each batch of plastic has stable and repeatable molding and processing performance.
(2) requirements of molding method on plastics.
High pressure extrusion blow molding.The plasticizing of molten material, the melt in the flow channel (such as mold core, diversion comb) 屮, be able to merge has no obvious seam line, stable parison;The self - weight sag of billet is not obvious and has enough melt strength.The clamping section of the billet has good weld ability.The melt flow rate of the material is low.
Potassium injection blow molding, stretch blow molding.The melt flow rate of the material is high, the melt is easy to flow, low viscosity, and can quickly fill the heat flow xiao or polyfilm cavity.The strength of the melt is lower than that of extrusion molding.
Press multilayer blow molding.When multi-layer co-extrusion blow molding, the materials of the co-extruded layers should meet the requirements of composite layers.The adhesive layer should have enough adhesive force.The barrier layer shall meet the requirements of the product for the barrier property and product performance.If the support layer adopts the material with high melt strength, other layers can use the material with low melt strength.The melt flow velocity of the material is low and the self - weight sag of the billet is not obvious.