Best Gold Pearlescent Pigment Solutions


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Place: Shanghai, China

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Jiangsu Pritty Pearlescent Pigment
Fumin Road 399
223800 Suqian, China

 


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sales@prittypigments.com

+86   21 6405 8221

+86 150 2681 0392

 

 

 

Plastic Blow Molding

Pritty Pearlescent Pigments give you the solution for your plastic molding manufacturing process.  Pearlescent pigments are suitable for reach a homogenous mass that retains its colour no matter how finely its ground.

 

How works

Plastic Blow Molding is a manufacturing process is how hollow plastic parts such as bottles and other applications are made. The plastic blow molding process was developed from a glass blowing process where a hollow glob of molten glass is placed in a form / mold and then air pressure inflates the glass glob into the shape of the form / mold. For plastic blow molding the process is very similar to the glassblowing process where as an extruded hollow plastic tube or injection molded preform is heated until it is sufficiently elastic then placed into a form / mold when air pressure inflates the hollow plastic tube or preform into the desired shape of the form or mold. When the plastic piece has cooled sufficiently and hardened the mold / form opens and the now formed plastic part is ejected.

 

 

For the extrusion of plastics the raw compound material is in the form of what are called “nurdles” (small beads or pellets which are often called “resin” in the industry) which are in a top mounted hopper and are gravity fed into the barrel of the extruder which contains a rotating screw which forces the plastic beads into the heated barrel where they are melted.

 

Additives such as colourants, UV inhibitors and effect pigments are often used and can be mixed into the beads prior to arriving at the hopper which then is called a “Masterbatch”. Effect pigments differ from organic pigments as they are comprised of non-homogenous individual structured platelets of a set range of sizes which give the pearlescent effect rather than organic pigments which are a homogenous mass that retains its colour no matter how finely its ground. Therefore when using effect pigments care must be taken with the mixing and the extrusion process such as screw speed and filters to not damage the effect pigment platelets by exerting excessive shear force which will dramatically reduce the pearlescent lustre effect.

 

The plastic extrusion process has much in common with plastic injection molding from the point of view of how the plastic is fed into the machine but differs as injection molding is not a continuous process while plastic extrusion is a continuous process.

Pritty’s effect pigments are well suited to the plastic extrusion blow moulding process, since the extrusion process ensures the effect pigment platelets are perfectly aligned to the surface which is critically important for the maximum pearlescent optical effect.

 

 

Plastic co-extrusion is well suited for use with Pritty effect pigments. This co-extrusion process is where multiple layers of plastic material are extruded simultaneously by utilizing two or more extruders to melt and deliver a steady volume of different plastics to a single extrusion head (die) for the desired shape or form. Co-extrusion is often used for example for plastic blow molded shampoo and personal care bottles where as the only the thin transparent or translucent top plastic outer layer contains Pritty effect pigments while the opaque bottom plastic layer is for the colour, shape and the strength of the bottle. This is an economic efficient option of having Pritty effect pigments only at the transparent or translucent surface of the plastic bottle rather than throughout the entire plastic bottle where light cannot penetrate so they cannot contribute to the pearlescent effect. In this way when using Pritty effect pigments plastic co-extrusion for blow molding is a good solution for combining high coverage, excellent pearlescent effects and good economy with minimal wastage of the effect pigments.