Polypropylene (PP) is less dense than water and has a melting point of 320°F.
Polypropylene is often used to manufacture tools that need to be regularly sterilized. Polypropylene, which is commonly known as PP, is similar to polyethylene in that it is very affordable financially, but polypropylene is much stronger. Polypropylene has been available in sheet form since the 1960s. It is available in an assortment of thicknesses and can be manufactured to meet the needs of a variety of industries.
Like PVC, which is also known as polyvinyl chloride, it is also able to retain color, and is therefore available in a variety of hues as well. Polypropylene manufacturers can form this plastic material into a variety of shapes, including rods, pipes, tubes, film and many more. It can also be utilized as a fiber as well as a structural plastic.
Polypropylene may be shaped for further manufacturing through two major processes; extrusion and molding. The extrusion of PP involves melt blown and spun-bond fibers of polypropylene that are stretched and rolled up and shipped to manufacturers. The molding of PP involves heating, mixing and forcing the substance into a die cast mold, where it then hardens in that shape. Molds are made from sturdy metals or plastics that will not be affected nor will taint the melted plastic inside them.
Due to its many favorable attributes and low cost, polypropylene serves many purposes. Polypropylene is used to make various textiles, carpets, plastic furniture, food packaging, reusable containers, bottles, floating ropes, automotive components, military thermal clothing, and luggage. Because PP is dishwasher safe, it is also popular for manufacturing food storage containers.
For recycling purposes, the Society of Plastics Industry has given specific resin identification codes to plastics, according to their polymer structure. These numbers are specified on the bottom of recyclable objects; they are enclosed in a rounded triangle outlined in clockwise arrows. Polypropylene is recyclable and carries the number five under its PP symbol.
Research continues with polypropylene, as it does with many plastic substances. Scientists are experimenting with different synthesizing methods that change the chemical body of the plastic, resulting in physical variances. Some of these experiments are yielding new types of polypropylene that are very exciting, particularly those that have a softer feel then the rigidness of the current polypropylene substances.
Because these newer versions of polypropylene have more elasticity, they are that much more shatter resistant and therefore open up new options for industries already utilizing it.