Over the last 50 years or so since plastic became more and more prevalent, over one billion tons of it has been disposed of and that number only continues to grow. Plastic, because of its molecular structure does take along time to decompose and cannot be burned due to it releasing harmful toxins and pollutants into the air. However since the mid 1990’s, plastic recycling has become more advanced and a greater awareness has been established. Since this time though, new technologies have been implemented making it easier to recycle and making people more conscious to do so. Curbside containers and designated recycling stations have vastly improved the way we dispose of these materials. These programs helped pave the way for a new era where plastics are less likely to be littered on the side of the road and to make it easier to be reused over and over again saving money, energy and helping the environment.
Some of the main plastics which can be recyclable are:
Polyester or PET carries the number 1 symbol. This plastic is primarily used for soft drink bottles. It is the easiest to recycle plastic and can be reground and reused time and time again.
The plastic with the number 2 symbol on it is HDPE which is a plastic primarily used for grocery bags, milk jugs and laundry detergent bottles.
PVC has the number 3 symbol and is used for pipes, fences and non-food containers.
LDPE is number 4 and is used for tubing, caps, rings and shrink wrap (coffee can lids).
Polypropylene has the number 5 symbol and its uses are for automotive parts, food containers and dishware.
Polystyrene is number 6 and is used for food containers and cups (including Styrofoam).
7 is other material such as Acrylic, fiberglass and Polycarbonate. These plastics are used for lenses, glasses and shields.
ABS is the number 9 symbol and is used in automotive, model building and molded parts.
Join the grass roots groups to recycle
Many schools and organizations work to collect and recycle materials, including plastics and aluminum cans. The biggest problem with plastic recycling is that it needs to be so meticulously carried out and requires painstaking time to sort properly and to go through the plastics. This is why the resin identification coding system was implemented in 1988 to help better identify plastics. The number in the middle has no real significance and is just there to help name the plastic the item is made from. This system has greatly improved the way plastics are handled and recycled leading to greater efficiency and better consistency when sorting through plastic resins.
There are, however, some plastics that cannot be recycled. These plastics are called thermosets, which are plastics that cannot return to their original form. The best example of this type of plastic is Phenolic which was the first commercially available plastic back in 1907, and was originally called Bakelite. It is primarily used for electrical and mechanical purposes. Unlike thermoplastics which can be formed and returned to their original shape, thermosets cannot due to their chemical makeup and they frequently have additives or fillers. Thermosets form above the melting temperature so when they are heated, the decomposition temperature is reached before the melt point.
Many of these thermoset materials replace other, much more expensive materials, and generally out last the former material by as much as 20 times. In practice, these material reduce the usage of natural resources and the ‘carbon footprint’ used to produce the items. One such material is the Nylon bushings used in large ships. The Nylon replaces a large Bronze bushing that used to be replaced once a year, and required the ship be put into dry dock to remove and replace the bushing. The new Nylon bushings out perform the bronze, and will last over 12 times longer. Dramatic savings in materials, casting new bronze bushing and the loss of sailing time of these ships.
Thanks to recycling improvements in the last 25 years, recycling has become much more efficient. Because of these programs better care has been taken to insure that plastic is not littered or discarded lightly, and that the programs created are easily accessible so people can take better care of their trash and better care of the earth. Plastics manufacturer commonly work to reuse and recycle materials during production. Many materials are available as ‘reprocessed’ or ‘commercial grade’ materials, meaning they contain a percentage of material that has been processed before. The first time a plastic resin is sent through the manufacturing process, that resin is referred to as ‘virgin resin’. Any further processing, the material must be referred to as reprocessed.
Want more information on the recycling of plastics, click here for recycling information. You may also contact us if you have a specific material question at: 866-832-9315, we are happy to assist.
Acetal Copolymer and ABS (Acrylonitrile-Butadiene-Stryene) have some similar properties but are really very different materials. They similarities are: high impact strength, ease of machining with standard cutting tools and good mechanical properties. They are also both FDA compliant and are both good substitutes for brass. They also have great water absorption resistance and good electrical properties. Both materials are good for some of the same applications but certainly not all. Listed below are some of the major differences.
ABS Sheet and Rod Information
ABS comes as Natural (straw) and Black color in Plate, Slab, Sheets and Rods, and thin sheet (.040″ – .250″) it is available as White or Black with a textured surface one side. It can be cut from 48″ X 96″ sheets into strip, panels or pieces.
ABS is formable. ABS is a great thermo-formable material while Acetal is not. Acetal is used more for machined parts such as gears and screws. ABS is great for molding and shaping parts from vacuum to heat forming. Excellent for model building and prototype projects.
ABS is easily bondable (similar to PVC). ABS can be bonded or welded to itself. Because Acetal is self lubricating, it is not possible for anything to stick to it unless etching is done – therefor it is not bondable.
ABS is a great material for painting and silk screening. While Acetal can not be painted or silk screened unless it has undergone Corona Treating (a flame surface treatment), but if treated will nice paint or screened surface.
ABS has better chemical resistance than Acetals. Both are attacked by acids like sulfuric, but ABS has a wider range of resistance to chemicals like aqueous acids, alkaline and alcohol. Acetal will degrade when exposed to such chemicals as chlorine and alkaline.
Specialty grades of ABS are available, including: Glass Filled, Static Dissipating, and Fire Retardant Grades (like Royalite – R59)
ABS Typical Properties Table
1.08 – 1.25
Izod Impact – Notched
Hardness – Rockwell
Deflection Temp @ 264psi
Co. Thermal Expansion
Acetal Copolymer and Homopolymer Sheet and Rod Information
ABS Resin Structure
Acetal is the better machining plastic, considered the best machining plastic material. Because of its durability and wear resistance, Acetal is an excellent choice for producing a wide variety of parts that require high wear resistance over a wide period of time. When machining to tight and specific tolerances, Acetal is ideal.
Acetal has low co-efficient of friction. Due to its self lubricating properties, it is a great material for sliding and wear applications. This material provides years of maintenance free bushings and bearings.
Acetal sheet is produced from .062″ – over 6″ thick and sheet sizes of up to 48″ X 120″ as standard. The standard color for Acetal and Delrin is Natural (a deep milky white) and Black. Some colors are available as Medical Grade, and can be obtained in limited sizes. These sheet are available cut to: slabs, blocks, plates, slabs and blocks.
Acetal (Polyoxymethylene) can be both a homopolymer and a copolymer. The homopolymer acetal has a repeating chain of one atom while the Acetal copolymer has two atoms forming a repeating chain. Dupont™ Delrin® is a popular acetal homopolymer brand name and the most commonly used acetal homopolymer.
Acetal – Delrin Properties Table
Typical Value Unfilled Homo-Polymer
Typical Value Unfilled Co-Polymer
Tensile Strength Yield
9,600 – 11,000
9,000 – 10,200
Izod Impact – Notched
Hardness – Rockwell
Deflection Temp @ 264psi
Deflection Temp @ 66 psi
Water Absorption @ 24 hrs
Co. Thermal Expansion
ABS and Acetal – Similar, but very different materials
Both of these materials possess excellent qualities and have a wide range of different uses. Acetal is great for machining, while ABS is great for forming and bonding. They both can be used for machined parts and are great choices for food contact and electrical applications. These two materials are both strong and durable plastics, but one might be better than the other for a specific job. When picking the right plastic, it is important to compare plastics and their specific properties to make sure the material won’t fail and that your job will be successful.
Contact us for additional information, call us at 866-832-9315 or contact us here. Consider Industrial Plastic Supply for all your plastic needs, we want to be your go-to plastic supplier.
**Note: Delrin® is a registered Trademark of Dupont