What Type of Plastic is PP?

2019.12.23Share:

What is PP?

 

Polypropylene fabric is a term used to describe any textile derived from the thermoplastic polymer polypropylene. PP is an acronym for polypropylene and is a thermoplastic made from nanotube gas in the presence of a catalyst, such as titanium chloride. This type of plastic is part of a polyolefin group and is non-polar and partially crystalline. Polypropylene is second only to polyethylene and is the second largest plastic produced in the world. Compared to textile production, polypropylene is more commonly used in packaging, straws, and other types of consumer and industrial products.

This type of plastic was originally developed in 1951 by the American company Phillips Petroleum. Chemists Robert Banks and J. Paul Hogan attempted to extract gasoline from propylene and accidentally made polypropylene. Although the experiment was considered a failure, it was quickly recognized that this new compound has comparable potential to polyethylene in many applications. By 1957, its popularity had surged, and extensive commercial production began across Europe. Today it is one of the most commonly used plastics in the world.

Since the 1980s, polypropylene production and applications have increased due to more efficient catalyst types and enhanced performance.

 

Why is polypropylene used so frequently?

 

Polypropylene can be used in domestic and industrial applications. Its unique properties and ability to adapt to various manufacturing technologies make it a valuable material for a wide range of applications. Another immeasurable feature is that polypropylene can function as both a plastic material and a fiber (for example, promotional handbags that are given away at events, competitions, etc.). Polypropylene’s unique ability to be manufactured by different methods and different uses means that it quickly began to challenge many old alternative materials, especially in the packaging, fiber and injection molding industries. Its growth has continued for many years and remains a major player in the global plastics industry.

At Creative Mechanisms, we have used polypropylene for many applications in many industries. Perhaps the most interesting examples include our ability to CNC process polypropylene to include living hinges for prototype living hinge development. Polypropylene is a very soft, soft material with a relatively low melting point. These factors prevent most people from properly processing materials.

 

How is Polypropylene made?

 

PP polymers are made by polymerizing the monomer propylene with the help of a catalyst. Propylene is a basic monomer that is gaseous at room temperature and is used in the production of PP.

There are many commercial techniques used to make pp polymers. Depending on the technology, the pp polymers produced have unique properties. All technologies have similar basic steps. PP polymer production steps

First, the raw materials and additives must be purified. Catalyst materials should be prepared. The raw material used was propylene.

The polymerization reaction is then carried out either in the gas phase with a fluidized bed / stirred reactor or in the liquid phase with a slurry / solution.

The polymer particles are then separated from the existing monomers and diluents. The monomer and diluent are recovered and re-fed in the process.

 

Is PP safe? Any products made from PP?

 

PP is recycling number 5 and is used for structural plastics and fibers.

In food containers there is a common use of PP. PP does not contain BPA. Also,it has a high melting point, so it can be used in dishwashers and microwave ovens.

Due to its fatigue resistance, most hinge-type products are also made of PP. (such as lock-type Tupperware, flip-top bottles, etc.).

PP is commonly used for storage containers. The softer rubber cover is made of a softer plastic, usually LDPE.

Products made from PVC can be made of polypropylene also . For example, PVC pipes can also be manufactured using PP. Some furniture (such as tables and chairs) can also use PP instead.

PP is commonly used in non-woven fabrics (for diapers and or hygiene products).

Polypropylene is commonly used in the production of carpets,ropes and recycled plastic carpets.

Many stationary products, such as notebook covers, plastic folders, storage boxes,paper protectors are also made of PP. The products are made through a plastic extrusion process.

PP injection molded parts.

 

How to recycle PP?

 

PP is 100% recyclable. Car battery boxes, signal lights, battery cables, brooms, brushes, ice scrapers, etc. are all examples made of recycled polypropylene (rPP).

The PP recovery process mainly involves melting the waste plastic to 250℃ to

remove contaminants, then removing the remaining molecules under vacuum and curing at a temperature close to 140 ° C. This recycled PP can be mixed with the original PP at a mixing ratio of up to 50%. The main challenge with PP recycling is its consumption-nearly 1% of PP bottles are currently recycled, compared to 98% for PET and HDPE bottles.

The use of PP is considered safe because from an occupational health and safety perspective, PP has no significant effect on chemical toxicity.

Although PP can easily become one of the most popular plastic packaging materials in the world, only about 1% is recycled, which means that most PP will be shipped to landfills. These will slowly decompose within 20-30 years. In addition to toxic additives such as lead and cadmium in PP, this also poses serious environmental problems. Incineration may release dioxins and vinyl chloride, both of which are toxic.

To determine the recyclability of polypropylene, the company conducted a “life-cycle” study to study the plastics in the final stages from raw material production to waste management to assess the sustainability of the product. The general consensus of these studies is that PP has great potential as a sustainable product.

In order to make polypropylene recycling economically viable, several factors must be considered, the most important being its difficulty and cost.

There are five steps in PP recycling, namely collection, sorting, cleaning, post-processing and production of new products.

Plastics usually carry a printed “Resin Code” (PP 5), which can be useful during plastic recycling because they indicate the type of plastic. This ensures that different types of plastic are separated and effectively recovered.