Plastics
Plastics are defined as a mixture of polymers which can be molded into various forms when subjected to heat or pressure. Plastics are divided into two main categories—thermoplastics and thermosettings.
At room temperature, thermoplastics are solid, polymer pellets that require the addition of heat to be melted into various shapes, while thermosetting plastics are typically a liquid at room temperature. Thermosetting plastics require a catalyst in order to be converted to a solid and "cured."
History of Plastics & Asbestos
The first major plastic invention occurred in 1907, when Leo Hendrik Baekeland discovered a moldable, inexpensive, nearly indestructible resin he called Bakelite. Bakelite was widely used in the early 1900s in the automotive and electrical industries, and the plastic was used in everything from telephones to steering wheels during this time.
Prized for its ability to withstand heat, flames and electrical current, Bakelite and other early plastics may have contained the mineral asbestos. Minerals were often added to plastics to serve as a filler agent, adding strength, stiffness, chemical resistance, thermal stability and safety. Popular reinforcement fillers include fiberglass, cellulose, carbon and asbestos. In fact, an estimated 2.9 percent of all reinforcement materials were asbestos fibers up until the late 1980s. In the mid-1980s, researchers estimate that most plastics contained as much as 17 percent asbestos.
Asbestos was widely used in the following types of plastics:
- PVC (polyvinyl chloride polymer) in vinyl asbestos tile
- Nylon
- Polypropylene
- Polyesters
The mineral could be added during the manufacturing process in the form of loose fibers, asbestos mats, paper, yarn, felt or cloth.
Uses for Asbestos-Reinforced Plastics
Asbestos-reinforced plastics and asbestos-filled plastics were used in thousands of products until the late 1980s, when the U.S. Environmental Protection Agency (EPA) banned the manufacture, processing and distribution of most products containing asbestos. Asbestos was commonly used in the following plastic products, in addition to many others:
- Arc chutes
- Cladding panels
- Electrical panels and partitions
- Switching panels
- Terminal boards and blocks
- Vinyl floor tile
- Vinyl sheet flooring
- Vinyl wallpaper
- Plastic casings for switches and controllers
Today, asbestos can be found in many products manufactured prior to the late-1980s. Modern-day alternatives to asbestos filler include cotton, carbon fiber, fiberglass, clays, mica, talc and Wollastonite.
Hazards of Asbestos-Reinforced Plastics
As long as asbestos-reinforced plastics are left undisturbed and are in good condition, they do not pose a significant health hazard. However, if plastics containing asbestos are significantly worn, aged or otherwise deteriorated, microscopic asbestos particles may become dislodged from the material and pose a health hazard.
Asbestos fibers can easily become airborne if embedded fibers are disturbed or released during sawing, sanding, drilling or cutting. When airborne asbestos fibers are inhaled or ingested, the materials can become lodged in the lungs and lead to the development of serious asbestos-related diseases such as lung cancer, mesothelioma and asbestosis.
Airborne fibers can also travel through the air and land on the clothing of nearby individuals or family members, which can place other individuals at risk of asbestos exposure.
People at risk for asbestos-reinforced plastics exposure include:
- Floor and wallpaper installers
- Demolition crews
- Truck drivers or railcar workers who transported the powdered plastic compound
- Electricians
- People who manufactured plastics and plastic molding compounds
- People who worked with compression molding or injection molding processes
- Remodelers
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© 2012 The Mesothelioma Center |
Last Modified Thursday, February 9th, 2012 | Disclaimer | Privacy Policy |
The information provided by The Mesothelioma Center is not a substitute for professional medical advice, diagnosis or treatment.
Sponsored by a law firm concentrating in asbestos litigation, The Peterson Firm, LLP with offices at 1350 Connecticut Ave, NW, Fifth Floor, Washington DC 20036.
