Polypropylene (PP) resin is the thermoplastic polymer. Because of that, it is able to be formed with heat and re-melted without losing its intrinsic characteristics. PP resin is usually opaque, however it can be made transparent for see-through packaging. PP resin has a narrow temperature range. It also has quite low-density with great thermoforming and injection molding characteristics.
First, polypropylene is made during the polymerization process of propylene gas in the presence of a catalyst system, using for example Ziegler-Natta or metallocene catalyst. Because polymerization conditions may differ (temperature, pressure and reactant concentrations), these conditions can be changed in order to achieve the specific grade of polypropylene. Later on, after the PP is produced, it can be processed using different additives to acquire desired resins.
Most commonly, PP resin is used in different types of packaging. It can be used for flexible or rigid packaging, especially common in the food industry. Because of its resistance to moisture and chemicals, it can be found in bottles and jars for different substances (condiments, detergent and toiletries); and thin-wall containers (yogurt cups, disposable hot drinks cups).
PP is also used in the clothing production industry (for thermal underwear, tote bags, sports clothes and more).
This chemical can also be found in materials used in the medical industry, for example in equipment, tools, containers, disposable syringes, Petri dishes, vials and more.