It is using the injection moulding method to make the plastic material to be parison, then move the hot parison to the
settled blow mould area to make the parison into a finished plastic product.
and thread quality , Advance adjustment of parison thickness, Good glossy product, economize raw materials.
But the injection and blow moulding is not suitable for the production of large and complex shape of container, and
because to use injection and blow molding technique, so the equipment investment is large.
So, it is mainly produce simple and small size bottle. The materials are usually to be PP, PS, HDPE, PVC, PET, PA etc.
It is mainly used in medicine, food, and cosmetics packaging.
The main raw material and the typical formula:
1) PE, Generally select melt index for 1~ 6 polyethylene resin.
2) PP, Generally select melt index for 2 - 4 polypropylene resin.
3) PS, Generally select universal or impact type injection level polystyrene resin.
1, process control of injection parison
1)Injection temperature :
It is related to varieties and characteristics of the raw materials, the type injection molding machine and product thickness
and other factors.For crystalline resin, such as polyethylene, polypropylene, injection temperature should be higher than
the melting point.
For amorphous polymer, such as polystyrene, polyvinyl chloride (PVC), injection temperature higher than the temperature
of viscous flow. The injection temperature of melt batch number low resin is higher than melt index high resin.
The injection temperature of thin wall parison is higher than thick wall parison.
General polystyrene injection temperature of 140 ℃ ~ 240 ℃, polyethylene for 150 ℃ ~ 280 ℃, polypropylene for 205 ℃ ~
285 ℃, polyvinyl chloride (PVC) for 160 ℃ ~ 190 ℃. Injection mold temperature is commonly 40 ℃ ~ 80 ℃.
2)Injection pressure
General resin melt index is low, the parison wall thin, then injection pressure need to be high, conversely need to be low.
Plunger type injection molding machine need higher pressure than screw injection molding machine.
In order to guarantee product quality, use lower injection pressure as far as possible.
General polystyrene injection pressure is 58.8 ~ 107.9 MPa, polyethylene is 58.8 ~ 98.06 MPa, polypropylene is 54.9 ~
98.06 MPa, polyvinyl chloride (PVC) is 78.4 ~ 127.5 MPa.
2, Blow molding process control and extrusion - blow molding of blow molding process are basic the same.
The main equipment and characteristics
1) Parison injection machine
The structure of this injection molding machine has the general basic characteristic, but injection pressure is low, screw
length to diameter ratio can be smaller, compression ratio also should not be too big.
2) Mould, it includes injection mould and blow mold.
Injection parison of moulds and general injection mould materials and processing requirements are basically the same,
but core module must be hollow, in order to pass into the compressed air.
3) Demoulding device
That is different from Extrusion blow moulding, cause when blow molding process is completed, open the blow molding
mold, it will bring molding products core die sent to the take off membrane device, the knockout plate will products and core die separate.
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Canvard Packaging Factory is a leading supplier of both custom and stock packaging of containers. We mainly produce empty lotion bottles, shampoo bottles, airless pump bottles, cosmetic jar, plastic tube with caps, detergent bottles, deodorant stick tube, PVC box, plastic box, paper bag since 2006. We got customers from China, America, Arab, France, Thailand etc. We offer one stand service from design, manufacturing to door to door shipment service.
http://www.cosmetic-bottles.com
