4-polypropylene-molecule
Polypropylene is a very useful plastic for injection molding. In addition to the conventional plastic applications, polypropylene also lends itself well in fiber applications, which give it even a wider range of uses that goes beyond just injection molding, including: ropes, carpets, upholstery, clothing, and the like. Polypropylene has gained popularity since it was first synthesized in the 50s. According to some reports, the current global demand for the material generates an annual market of about 45 million metric tons and it is estimated that the demand will rise to approximately 62 million metric tons by 2020. The major end users of polypropylene are the packaging industry, which consumes about 30% of the total, followed by the electrical and equipment manufacturing, which uses about 13% each. Household appliances and automotive industries both consume 10% each and construction materials follows with 5% of the market. Other applications together make up the rest of the global polypropylene consumption.
POLYPROPYLENE AS AN INJECTION MOLDING PLASTIC
Polypropylene is a very popular material in the injection molding world; this popularity is due to it being a very ‘moldable’ material. Its versatility, wide range of uses, and unique properties are among those reasons. Polypropylene is easy to mold despite its semi-crystalline nature, and it flows very wellbecause of its low melt viscosity. This property significantly enhances the rate at which you can fill up a mold with the material. The rate should not be set too high, however, to ensure good surface finish and to avoid defects such as voids, weld lines, and flow fronts. The melt temperature of polypropylene can be anywhere between 200oC (392oF) to 250oC (482oF), although it can go higher depending on the grade of polypropylene and the kind of additives it contains. Shrinkage in polypropylene is about 1% but can vary based on a number of factors, including holding pressure, holding time, melt temperature, mold wall thickness, mold temperature, and the percentage and type of additives.
POLYPROPYLENE AS A CNC MACHINABLE PLASTIC
Polypropylene has gained a reputation as a material that cannot be machined. This is because it has a low annealing temperature, which means that it starts to deform under heat. Because it is a very soft material in general, it requires an extremely high skill level to be cut with precision; Creative Mechanisms has been successful in doing so. Our teams can use a CNC machine and cut the polypropylene cleanly and with extremely great detail.
In addition, we are able to create living hinges with polypropylene that have thickness as little as .010 inches. Making living hinges is a difficult endeavor on its own, which makes using a difficult material like polypropylene even more impressive.
