PP – Polypropylene
Polypropylene is the polymer with the largest growth rate in the world, due to its exceptional properties and versatility of application. Polypropylene is a semicrystalline thermoplastic, produced by polymerizing process of propylene monomer using a stereospecific catalyst forming long chains. Among numerous properties of this material may be highlighted the following:
- The density of polypropylene is about 0.905 g/cm3, one of the lowest among all plastic materials commercially available. This allows to obtain parts with low weight.
- Provides high rigidity, superior to most commercial plastics.
- Good impact resistance at enviroment temperature for all types of polypropylene.
- Excellent transparency.
- High flexibility resistance.
- High surface hardness.
- High chemical resistance and it is not attacked by the great majority of chemicals at enviroment temperature.
- Very low water absorption.
- Low permeability to water vapor.
- Very low electrical conductivity.
There are three main types of PP: homopolymers, random copolymers and heterophasic copolymers.
Each type has specific applications and may be modified and adapted to different uses by the techniques of formulation .
High temperature resistance. It can be sterilized with gamma ray and ethylene oxide. Below 80°C has good chemical resistance to acids and bases and few organic solvents can dissolve it at enviroment temperature. It has excellent electrical and mechanical resistance. It becomes fragile at temperatures below 0ºC. Used in continuous filaments for ropes and carpets, nonwovens by spunbound and melt blown process for diapers, hospital products, absorbents, housewares, lids seal, blown articles in general (mineral water, detergent, etc.), sheet extrusion for thermoforming cups, food packaging, BOPP films, bags, etc
It has excellent mechanical strength at low temperatures. More flexible and durable than the PP homopolymer. Its strength is increased when modified with thermoplastic rubber. However, its chemical resistance is lower than PP homopolymer. Used to make lids, buckets, toys, housewares, automotive parts and appliances, battery box, containers, garden furniture, etc.
Indicated to injection molding process. It has low odor and taste, good processability, high productivity, excellent transparency and gloss and great balance stiffness / impact. It is used to make domestic appliances, packaging for cosmetics, freezer container and high transparency buckets.