HDPE English full name: High Density Polyethylene
Material feature editing
【 abbreviation 】HDPE
High density polyethylene
Low pressure ethylene[monomer] ethylene
Hdpe is a kind of opaque white waxy material, the specific gravity is lighter than water, the specific gravity is 0.941~0.960, soft and toughness, but slightly harder than LDPE, also slightly elongation, non-toxic, tasteless.
[combustion characteristics] flammable, can continue to burn after leaving the fire, the upper end of the flame is yellow, the lower end is blue, melting when burning, liquid dripping, no black smoke out, at the same time, emit the smell of paraffin burning.
[main advantages] acid and alkali resistance, resistance to organic solvents, excellent electrical insulation, low temperature, can still maintain a certain toughness. Surface hardness, tensile strength, rigidity and other mechanical strength are higher than LDPE, close to PP, PP than toughness, but the surface finish is not as good as PP.
[main disadvantages] poor mechanical performance, poor permeability, easy to deformation, easy to aging, brittle, brittle than PP, easy to stress cracking, low surface hardness, easy to scratch. Difficult to print, printing, the need for surface discharge treatment, not electroplating, surface dull.
[application] used for extruding packing film, rope, woven bag, fishing net, water pipe;Injection low-grade commodity and shell, non-load bearing components, plastic box, turnover box; Extrusion blow molding containers, hollow products, bottles.
HDPE has countless applications, ranging from reusable thin-walled beverage cups to 5-gsl cans, consuming 1/5 of the HDPE produced domestically. Generally speaking, the melt index of injection molding grade is 5 ~ 10, and there are low fluidity grade with toughness and high fluidity grade with machinability. USES include daily necessities and food thin-walled packaging; Durable food and paint cans; High resistance to environmental stress cracking applications such as small engine fuel tanks and 90-gal waste tanks.
The melting point of HDPE is 142℃ and the decomposition temperature is 300℃. Injection molding temperature adjustable range is larger. When injection molding, the general use temperature is 180℃- 230℃; Because it is an olefin plastic, it does not absorb water. During production, it does not need to be dried. However, for the sake of product quality, it can be dried at 60℃ for 1hr to discharge floating water. The melt viscosity of polyethylene is large, the length ratio is small, thin wall products may lack of glue, therefore, the gate and flow channel are relatively large; Products with static electricity, easy to absorb surface angstrom. The contraction rate was 16‰; Overflow edge value is 0.05mm.