What is Polypropylene?

Polypropylene is a semi-rigid, cost-effective, and tough thermoplastic linear hydrocarbon polymer resin that offers excellent chemical, electrical, and fatigue resistance at high temperatures.

Characteristics of Polypropylene

The characteristics of Polypropylene include…

• Semi-rigid
• Translucent
• Good chemical resistance
• Tough
• Good fatigue resistance
• Integral hinge property
• Good heat resistance

PP does not present stress-cracking problems and offers excellent electrical and chemical resistance at higher temperatures. While the properties of PP are similar to those of Polyethylene, there are specific differences. These include a lower density, higher softening point (PP doesn’t melt below 160ºC, Polyethylene, a more common plastic, will anneal at around 100ºC) and higher rigidity and hardness. Additives are applied to all commercially produced polypropylene resins to protect the polymer during processing and to enhance end-use performance.

What are the advantages of polypropylene?

Polypropylene’s advantages are its strength and low cost. Its advantages in more detail:

• Widely accessible and cost-effective
• High flexural strength due to its semi-crystalline structure
• High resistance to moisture absorption and fatigue
• Great electrical insulator
• Chemically resistant to a variety of bases and acids

Uses of this plastic material

Polypropylene is used in a range of industries including packaging, material handling, and consumer goods:

• Material handling
• Packaging
• Medical devices
• Clothing
• Car parts
• Housewares
• Toys

Exemples:

1. Flexible Packaging

PP is one of the leading materials used for film extrusion and has in recent years benefited versus cellophane, metals and paper on account of its superior puncture resistance, low sealing threshold and competitive price. PP Film is available either as Cast Film or bi-axially orientated PP (BOPP). The film market may be divided in to three main sectors:

2. Rigid Packaging

Reusable and collapsible/stackable crates are a great application for PP, providing ease to transport (both full and empty) and allow simple, safe and efficient storage of products and are ideal for Just-in-Time (JIT) storage solutions. As a consequence, supermarkets are beginning to revert to use and similar products are finding application in the automotive supply chain.

3. Automotive

In the automotive sector PP is utilised as a monomaterial solution for automotive interiors. The monomaterial dashboard is becoming increasingly achievable, PP film cushioning, film skins, and powder slush moulding and even blow moulded parts with integral PP textile covers are emerging.

4. Consumer Products

Products classified in this sector are Housewares, Furniture, Appliances, Luggage, Toys, Battery Cases and other “durable” items for home, garden or leisure use. Injection Moulding dominates the conversion process used for these products.

Is it possible to recycle polypropylene?

Polypropylene can be recycled into many different types of products, such as fibers for clothing, industrial materials, kitchenware and much more.

What is the shelf life of polypropylene?

Polypropylene has limited heat resistance, but heat-stabilized grades are available for applications requiring prolonged use at elevated temperatures. Useful life of parts molded from such grades may be as long as 5 years at 121°C, 10 years at 110°C, and 20 years at 99°C.