Plastic bags have only been around for about 50 years, but they have quickly risen to become the most popular bagging method for grocery stores and other stores around the world. Many plastic manufacturers earn their living manufacturing only plastic bags and bottles.
In the last few years, plastic bags have received a bad reputation. Because the bags are difficult to degrade, this makes them less favored with the environmentally-friendly crowd. But are plastic bags really as much of a foe to the environment as people think?
During manufacturing, plastic bags can be manufactured for much less than a cent per bag. Many paper bags cost upwards of 5 cents a bag, and cloth bags cost much more. It is easier to store plastic bags, and they take up much less room that paper or cloth bags, saving the manufacturer a lot of money in storage and shipping costs.
If consumers recycle their paper bags, then they can be
better for the environment. However, plastic bags are easy to recycle as well.
In a landfill, paper bags contribute more to the accumulation of waste. During
manufacturing, the EPA estimates that it takes 40 percent more energy to create
paper bags. Paper bags also create 70 percent more air pollution than plastic
It is easy to see that the issue of what bag type is more eco-friendly is not as clear-cut as most people believe. In fact, using plastic bags might be the most eco-friendly option of all.
Plastic bags are extremely versatile containers or carriers made of thin and often flexible polymeric films. Used to store, transport, ship and package goods in a number of industrial, commercial and residential applications, baggies such as these prove very useful as they are most often waterproof and provide some degree of protection from the elements. Commonly referred to as poly bags, the containers are constructed of processed polymer resins.
Specific materials for plastic bags abound, but polyethylene bags, polypropylene bags and vinyl bags are among the most popular and find great use as anything from medical plastic bags to plastic shopping bags. Beyond the basic material construction, plastic bags as a grouping may have little else in common due to the extreme variety in not only material choice, but also size, color, shape, closure and style which exhibit extreme variation. The selection often depends on the intended use of the bag. Clear plastic bags, for example, are a popular choice for plastic merchandise bags as they allow consumers to preview items before purchase. Resealable plastic bags and zip lock bags are also purpose driven as they provide users with a reliable closing and the option to reuse and reseal bags for extended use. While many of these factors are determined in manufacturing, post-production options such as printed plastic bags ensure the perfect fit, both functionally and aesthetically, for any application for all industrial, home or commercial locations.
- Substance added to a polymer to increase
the effectiveness, but not the strength, of the polymer. Examples of
additives include flame-retardants, anti-static compounds, pigments and
- Also referred to as a "blend" or "hybrid," it is two chemically dissimilar polymers bonded together to form a new substance. However, each polymeric unit is representative of only one monomer.
- Common process of creating plastic bags in which compressed air fills an extruded plastic tube in order to enlarge and thin out the resin.
- A polymer made up of two monomers in which each repeating unit in the chain consists of units of both monomers.
- Very thin cracks in a polymeric material caused by chemicals or other agents, such as ultraviolet radiation.
- The length of the molecular or monomeric units in a polymer chain. This length determines the properties of the polymer.
- A copolymer produced through the chemical reaction of ethylene and vinyl acetate. EVA is often added to plastic resins to increase the strength of the resin in temperatures below freezing.
- A term referring to the thickness of the material. The smaller the gauge number, the thinner the material.
- Term that reflects the temperature
when a substance changes from a hard glass to a rubber consistency. Polymers
become weak at temperatures below their transition temperature.
- Polymers originating from the same chemical family and produced from the same company. However, they vary in weight, additives, reinforcements and the manner in which they are processed.
- Fusing together two or more thermoplastic films, such as low density polyethylene, through the application of heat and pressure.
- A plastic material whose thickness ranges from .941 -.965 g/cm3. HDPE is more expensive to process, but maintains greater strength, resistance and stiffness than either LDPE or LLDPE.
- The process of decreasing the weight of plastic by using less resin, while retaining the strength and effectiveness of the plastic.
- A plastic material that is produced at lower temperatures and pressures than LDPE through copolymerization, resulting in a crystalline structure responsible for greater stiffness and a higher melting point than LDPE. Although it is more difficult to process, LLDPE maintains greater tensile strength and a greater resistance to stress cracking than LDPE.
- The longer side of the bag that allows the bag to be opened more easily.
- The most common and least expensive plastic bag material that maintains a density of .910-.925 g/cm3. LDPE maintains its durability, flexibility, water resistance and clarity under low temperatures, and its low melting point makes it ideal for heat sealing.
- The temperature at which a substance converts from a solid into a liquid.
- A puncture resistant material that is thinner and stronger than LDPE.
- The most basic polymeric unit, usually a liquid or a gas, consisting of molecules from the same organic substance. When chained together, monomers form solid polymers.
- A chemical added to plastic resins to increase the flexibility of the plastic.
- The most common plastic resin, it is a light, chemically resistant thermoplastic used in packaging and insulation. PE resins used in the production of plastic bags include low density, linear low density and high density resins.
- Two or more
monomers bonded together through a chemical reaction. Each polymer consists
of a chain of repeating monomers.
- Light, durable thermoplastic with a high melting point that is often used in packaging. PP contains polymers consisting of propylene, a colorless, combustible gas found in petroleum.
- Substance added to a polymer to increase the strength of the plastic. Examples include clay, mica and glass fibers.
- A class of polymers, or plastics, chemically different to naturally occurring resin, a sticky substance obtained from certain trees and plants. Examples of resins include polyethylene, polyurethane and acrylics.
- An additive that aids in decreasing the slippage of stacked packaged goods and prevents bags from sticking together.
- A bottom seal for liners that combines four sections into a star design. Star seals are the strongest seals, and they maximize carrying capacity.
- Cracking that occurs as a result of mechanical stress. In most cases, tiny cracks caused from exposure of the plastic to chemicals or ultraviolet radiation are already present.
- A polymer made up of three monomers in which each repeating unit in the chain consists of units of all three monomers.
- The process of applying heat, pressure or suction to create plastic sheets, according to specified sizes and shapes.
- Category of plastics that has the potential to soften and reform when heated and to harden again during cooling. During the process, the physical makeup of the plastic does not change.
- A category of plastics that cannot be reformed upon reheating. Thermosets remain permanently hard.
- A plastic additive that increases the resistance of the plastic to the harmful effects of ultraviolet radiation, such as fading of color and strength decrease.
- Thermoplastic coating or film that safeguards sensitive items from harsh environmental conditions through the release of a vapor that forms a protective layer on the surface of the thermoplastic.