Modern plastics are commonly made from natural gas, crude oil, and other organic material. They have been loudly denounced as the most obvious symbol of a consumer society run amok, but have also become indispensable. Ironically, most criticism is written using a molded plastic computer keyboard. The process commonly used to transform plastic into useful components is called thermoforming.
The environmental impact of hydrocarbon use is difficult to ignore. Surprisingly, production of plastics uses less than 3% of all the oil and gas burned each year in the United States by vehicles. That is still a huge number, but illustrates how halting all production of plastic would do very little to end reliance on oil as a primary fuel, and would force consumer prices upward.
The material used in this process begins as a continuous sheet of acrylic, polypropylene, polyvinyl chloride, or other similar polymer. That thin layer is carefully heated to the point that it becomes pliable, but not liquid. Using one of three methods, it is then applied to a specifically designed mold, allowed to cool, and trimmed. The result is a smooth, finished piece or component.
The heat is provided by radiant electrical units positioned approximately five inches from the sheet. Different polymers require specific warming periods, but once the correct temperature has been reached, they are ready to be molded into the requested shape. The most common method is called vacuum forming, which employs negative pressure similar to a home vacuum device.
When a positive force is used, it is called pressure forming. Because vacuum processes are naturally limited, positive pressure can reach higher levels, making the process more versatile. The raw plastic is usually pre-stretched in order to avoid an uneven thickness over corners. After being applied, trapped air is released from the mold, and the product is cleaned up.
Many products require two-sided molds. The unformed plastic is heated, forced between the parts under pressure, and assumes the texture and shape of the space in between. This gives manufacturers much better control over important product details, but is costlier. Regardless of the method being used, only thermoplastics can survive reheating without breaking down.
Thicker sheets are used to manufacture electronics housings, medical equipment for daily care needs, external car components, and even in some bathroom accessories and fixtures. Thinner sizes are used to package cosmetics, many processed and fresh foods, and small, loose items like screws. While not biodegradable, methods of recycling and disposal are constantly improving.
The environmental impact of hydrocarbon use is difficult to ignore. Surprisingly, production of plastics uses less than 3% of all the oil and gas burned each year in the United States by vehicles. That is still a huge number, but illustrates how halting all production of plastic would do very little to end reliance on oil as a primary fuel, and would force consumer prices upward.
The material used in this process begins as a continuous sheet of acrylic, polypropylene, polyvinyl chloride, or other similar polymer. That thin layer is carefully heated to the point that it becomes pliable, but not liquid. Using one of three methods, it is then applied to a specifically designed mold, allowed to cool, and trimmed. The result is a smooth, finished piece or component.
The heat is provided by radiant electrical units positioned approximately five inches from the sheet. Different polymers require specific warming periods, but once the correct temperature has been reached, they are ready to be molded into the requested shape. The most common method is called vacuum forming, which employs negative pressure similar to a home vacuum device.
When a positive force is used, it is called pressure forming. Because vacuum processes are naturally limited, positive pressure can reach higher levels, making the process more versatile. The raw plastic is usually pre-stretched in order to avoid an uneven thickness over corners. After being applied, trapped air is released from the mold, and the product is cleaned up.
Many products require two-sided molds. The unformed plastic is heated, forced between the parts under pressure, and assumes the texture and shape of the space in between. This gives manufacturers much better control over important product details, but is costlier. Regardless of the method being used, only thermoplastics can survive reheating without breaking down.
Thicker sheets are used to manufacture electronics housings, medical equipment for daily care needs, external car components, and even in some bathroom accessories and fixtures. Thinner sizes are used to package cosmetics, many processed and fresh foods, and small, loose items like screws. While not biodegradable, methods of recycling and disposal are constantly improving.
About the Author:
Genevive B. Mata has over 20 years of professional sales experience, 10 of them directly in the plastic pallets and materials handling industry. On her spare time she works on applied-sustainability projects. If you are interested in plastic pallets price, she suggests you check out her friends PTM.
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