The Many Forms of Clear Plastic
Posted on 06, February, 2015
Last Modified on 20, March, 2015
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Clear plastic is one of the most common materials used in manufacturing. Designers and manufacturers frequently choose these transparent polymers as an alternative when traditional glass is too heavy or will break too easily. It is important to note, however, that there are all kinds of different clear plastics and each type has its advantages.
At A Glance: Cost & Durability Comparison
|Injection Molded Plastic||Slight yellowing with prolonged sunlight exposure; blue haze when removed from mold||Low||Yes||Scratches quite easily||$|
|Polycarbonate||Slight yellowing with prolonged sunlight exposure||High||Yes||Scratches easily||$$$$|
|Injection Molded Acrylic||No yellowing; some blue haze when removed from mold||Medium||Yes||Limited scratching; usually can be buffed out||$$|
|Hand-Crafted Acrylic||Extremely clear; no yellowing or blue haze||Medium||No||Limited scratching; usually can be buffed out||$$$|
Acrylic vs. Plastic
With so many options for clear plastic on the market, it is no surprise that lots of people misunderstand the differences between the types. Each type is made in a different way using different materials, which results in many different price points. We've put together this resource page to help sort out some of the most frequently asked questions, like "is acrylic a plastic or a glass?" and "what is the difference between acrylic and plastic?". While acrylic is a plastic, not all plastic is acrylic. The term "acrylic" represents a family of petroleum-based thermoplastics made from the derivation of natural gas. Another common name for acrylic is "polyacrylate" which is one of the most common types. This material is made from Methyl Methacrylate (MMA), Poly Methyl Methacrylate, or a combination of both.
What’s With All the Brand Names?
Although the composition is pretty much the same, acrylic has many brand names. Plexiglas was the original trademark name when the Rohm and Haas Company first introduced the product to a mass market, but many others have established their own brand names including Lucite by du Pont and Acrylite by Evonik Cyro LLC. Some other common brands are Perspex, Oroglass, Optix, and Altuglass.
Injection Molded Acrylic vs. Hand-Crafted Acrylic
Injection molded acrylic is manufactured by injecting acrylic or polymethyl methacrylate material into a mold. This transparent thermoplastic makes a great alternative to glass, which is why it is commonly used to manufacture bakery bins, sunglasses, and display risers. Unlike polystyrene, injection molded acrylic can be made without the issues of hazing or coloration. Additionally the material is much stronger and has minimal relief markings when removed from the mold. Injection molding takes less labor than hand-crafting, which results in a lower cost.
Hand-crafted acrylic is the most upscale plastic material we use when making our displays. Although hand-crafting the polymer is more time consuming and therefore costs a little more, the difference in quality is astounding. There are virtually no defects as a result of manufacturing, including common problems like relief marks or haze from molds. Unlike injection molding, all joints are bonded by hand using solvent agents that actually "melt" the material together. The result is a crystal clear construction that is extremely strong, which is why our hand-crafted acrylic display cases are so popular.
Other Types of Plastic
Injection molded polystyrene is an aromatic polymer made from a chemically bonded monomer styrene. Polystyrene is usually thinner and more brittle than acrylic but often costs quite a bit less than other plastics. Because the material is made using a mold, it can have relief markings as well as a blue haze effect when removed. For this reason, it is not the best product to preserve collectables and use for showcases. Many low-cost consumer goods are made from this injection molded polystyrene, like disposable razor blades, license plate frames, single-use dinnerware, and CD cases.
Polycarbonate is yet another type of thermoplastic polymer used in manufacturing. This clear plastic is typically more expensive than acrylic and polystyrene, but it is extremely strong. Many people associate polycarbonate with "bullet-proof glass" because it is the same material used to make armored windows in government motorcade vehicles as well as airplane windows. Lexan is one of the most popular brand names associated with polycarbonate, but a variety of other brands are also available on the market. One of the disadvantages of the material is that unlike acrylic it will yellow when exposed to prolonged sunlight.