Friday, June 5, 2015

Why should I care which plastic is used in my floors?

Plastics used in flooring and matting go by several different acronyms – PE, PP, PVC, LDPE, MDPE, HDPE, PEX. What does it all mean? And why should I care?

There are three commonly-used thermoplastics in the flooring industry. (Thermoplastics become soft and moldable upon heating and solidify again when cooled.) The three most commonly produced thermoplastics are polyethylene (PE), polypropylene (PP) and polyvinyl chloride (PVC). Each of those thermoplastics also have variations that affect their intended use. Here's how it works.

Waterproof PVC makes a good material for outdoor patio tiles.
PVC flooring is best used for outdoor applications.
Polyvinyl Chloride
PVC can be rigid (RPVC) or flexible. RPVC is usually used for piping, doors, windows, bank cards and non-food packaging, but it can be brittle. With the addition of phthalates (chemicals used to soften plastics), RPVC becomes softer and more flexible, making it suitable to replace rubber in many instances which is where it becomes useful in flooring. PVC flooring is inexpensive and versatile. Chlorinated PVC is resistant to fire, oils and many chemicals. It can also withstand extreme environmental conditions. In the flooring industry, PVC is popular due to its ability to prevent dirt buildup and fend off breeding of microbes in areas that need to be kept sterile. Its waterproof properties make it a popular material for outdoor patio tiles and sports courts.
Note: There is some concern over phthalates' health effects on humans as some studies have shown certain phthalate exposures to coincide with changes in hormone levels and increased birth defects in rodents. Phthalates typically do not persist in outdoor environments due to biodegradation, photodegradation and anaerobic degradation.
Polypropylene is good for garage floor tiles due to its resistance to high heats and chemicals.
Polypropylene flooring is highly resistant to heat
 and chemicals.

PP is free of bisphenol A (BPA), a common chemical in use for making plastics since the 1960s that has been found to seep into food or beverages, causing concern over possible health effects on the brain and prostate glands. PP is lightweight, strong and flexible and resistant to high heat – up to 200 degrees Celsius. It is also resistant to corrosion, chemicals and moisture. Polypropylene has a wide variety of uses, including packaging, thermal underwear, carpeting, laboratory equipment and automotive components. In the flooring industry, PP is often used for garage floor tiles, due to durability and load rating properties.

Gymnastics mats use cross-linked polyethylene foam.
Polyethylene is used to make shock absorbent foam.
PE is the most common plastic and comes in several different densities. Medium and high density polyethylene (MDPE and HDPE) have a melting point range of between 120 and 180 degrees Celsius. Low density polyethylene (LDPE) melts between 105 and 115 degrees Celsius. LDPE, MDPE and HDPE are all resistant to strong acids and bases as well as gentle oxidants and reducing agents.
One third of all toys are manufactured from HDPE which has high tensile strength. Cross-linked Polyethylene (PEX) foam used in gymnastics mats generally uses HDPE and provides a firm and strong closed-cell material. This material does well rebounding to its original shape, providing bounce, cushion and/or shock absorption.
MDPE has good shock absorption and is more resistant to notching and stress cracking than HDPE. MDPE is often used for gas pipes, bags and packaging film.
LDPE is more likely to deform under tensile stress. It is commonly used for both rigid containers and plastic films.

As you can see, there are both good and bad sides to each kind of plastic, making it important to think carefully about how and where these materials should and will be used.