Why food safe HDPE plastic replaced glass as the go-to milk container.
Many of you, should you be older than 60, may remember the “Milk Man”. This delivery service from decades ago, was a most common way of transporting milk to the consumer. Back then, suppliers used glass bottles, delivered by this milk man, right to your front door.
HDPE is Food Safe
When looking at alternatives, the milk processing industry found a use and benefit from replacing the glass with a plastic called High Density Polyethylene (HDPE). But what is HDPE, and what are the benefits of using it?
Glass is heavy, HDPE plastic is light
One of the characteristics of this thermoplastic is the weight of the material. The reason this is so beneficial brings us back to the milk jug. Old style glass milk containers could hold 32 oz., with the empty glass weighing 1.25 lbs. An empty gallon water or milk jug (128 oz.) weighs in at only 0.25 lbs, and holds 4 times more volume. When full, the milk jug can hold more volume than the glass bottle without compromising the strength, especially when being transported. This lowers the overall transport time and significantly reduces the cost of shipping.
This drop in weight and large increase in capacity is why the industry made the switch. The attribute of high durability in plastic materials like HDPE is known as the “strength to weight ratio”. As already mentioned, this was a huge benefit from switching to HDPE containers – the impact it has on transport costs. The high impact resistance of the material allows for easy transport. The HDPE jugs can withstand the jarring and bumping that is a natural part of mass transit, with almost zero wear or breakage to the product. Compared to the glass bottle, too hard of a turn or a pothole in the road could lead to the disheartening sound of shattering glass… not an ideal result for the distributing company. The HDPE impact resistance still holds true through out the supply chain, and even when the containers enter a store or home. If a HDPE milk jug should fall, the plastic container may spill, but it won’t cause the harm or damage that glass would. Broken glass poses a hazard and a risk, whereas plastic in this case can be easily cleaned, recycled, and used again.
When discussing this topic, the argument of recycling and sustainability sets its sights on plastics. In reality, the carbon footprint of plastics is much smaller than that of glass. The amount of heat necessary to heat up plastic for recycling is dramatically lower than that of glass, making it more sustainable in the long run. Yes, both are 100% recyclable, but the amount of fuel necessary plays a big factor. The temperature needed for melting and processing HDPE is between 248 and 356°F depending on grade. Whereas glass requires a minimum temperature of 2,600°F, according to SeattlePI. As you can see, these temperatures are very different, and shows why the life cycle of plastic is more eco-friendly and a better option to preserve our environment.
Immensely versatile HDPE applications
HDPE has many more uses, like in structural tanks, FDA approved cutting boards and industrial piping systems. This material outweighs most alternatives in benefits due to it’s cost and performance, and is produced in sheet and rod by many major manufacturers in the USA. HDPE plastics are FDA and NSF approved for food applications, making HDPE a food safe product for most food processing and packing applications. For more details on HDPE and it’s benefits see Industrial Plastic Supply or call 866-832-9315
What other applications could benefit from newer and improved materials to make our world safer, cleaner and more efficient?
Use the best available tools to narrow down the best plastic sheet material for your application.
What are the best methods to pick the proper plastic sheet material? Use the tools that the professionals use to find the best plastic material for your application.
Where To Begin
The process of picking the proper plastic material starts with determining the ‘must have’ physical properties needed for your application. Designing a part with the minimum performance factors in mind will help to eliminate an overly expensive part.
Critical factors to consider are:
Temperature requirements (short term and long term)
Chemical or Environmental Requirements
UV resistance (Will it be in direct sunlight)
Color or Transparency
Strengths (Impact and Compression)
Compliance Issues (Certification for FDA, NSF, Dairy, etc.)
Review The Plastic Property Comparison Guide
The first tool suggested is a chart produced by the IAPD (International Association of Plastic Distribution – http://iapd.org/) linked in picture below, and listed on this chart are the most common plastic sheet and plastic rod materials that are commonlyavailable. In addition, the chart compares the physical properties of these common plastic materials. Click on picture to access chart. Included in this chart is a relative cost comparison, which will assist in limiting the materials to proper plastics for a application without over-designing and using an expensive ‘over kill’ material. Some common plastic sheet materials can be very expensive. Materials like PEEK (PolyEtherEtherKetone) can be in the $100 per pound range or more.
Start Search With Temperature Resistance
After looking over the IAPD (International Association of Plastic Distribution) Physical Properties Chart above, now it is time to evaluate specifics for your application. The critical factors listed above are ranked by most important to least important. If your part needs to handle a continuoustemperature of 300 degrees F, this is a critical physical property. Picking a material that softens at 250 degrees is a recipe for disaster. Pick a material that can handle the temperature first.
Will Part Have Chemical Exposure
Next, look at environmental requirements. Parts exposed to chemicals are important to research. Find the chemical make up and the concentration of the chemical to insure the material you pick can handle this solution. Many plasticshave excellent chemical resistance as evidenced by evaluating the container the chemicals are stored in already. Acommon plastic that is chemical resistant is Polypropylene, the same material used for automotive batteries. While Polypropylene and HDPE sheets are excellent in chemical resistance, their temperature range is quite limited. Also,these two plastics can not be easily bonded or glued, and would require heat welding for assembly.
Does Your Part Live In The Sun
Most plastics do not handle long exposure to direct sunlight without an additional UV additive. The one exception is Acrylic, which is the most UV resistant plastic sheet available. Some plastics handle UV well if they have a carbonblack additive, or a extra UV package added at time of production.
How Critical Is The Color
The most common colors in many plastic sheets are Natural (white to tan) and Black. While other colors are available with a special run, this may require a large minimum order. Some plastics, like HDPE are available in many colors andtextures for use in marine, playground and food processing applications. In many plastic applications, a machined partis being made, and the color is the least important factor. If it is an internal part of a machine, no one really cares about the color of the part. Some clients look for materials in a specific color to help ‘brand’ their parts for easy replacementand identification.
Nylon with huge amount of stress, cooled too quickly.
How Much Stress Will The Part See
Strength is a wide range of physical properties covering many stresses a part may be exposed to. From impact to compression, expansion to tensile strength, all of these can be critical in designing a plastic part. There are otherfactors in the ‘Strength’ realm, like Notched Izod and water absorption. If your part will be exposed to crushing pressure, pulling apart force or impact, these are critical things to consider prior to picking your plastic part.
PTFE is asoft and slippery plastic, but will ‘cold flow’ under high pressure, and High Pressure Laminates like G-10 FR 4 sheetcan withstand some of the highest pressures. The Notched Izod tests for materials that break easily if a scored mark has been made in the surface. Acrylics break very easily if scored, but UHMW will not break at all under the same test.
What Agency Approval May Be Required
In many applications a part may require approval or testing to meet a third party certification. One such common application is for materials in food processing applications. Common requests included UL ratings, Fire Ratings, Military specifications and many more. Food contact is a popular request, covering material that is either FDA (Foodand Drug Administration) or NSF (National Sanitation Foundation) approved. These agencies insure that materials are rigorously tested and comply with their requirements for safety. Some common materials used in food processing that meet the FDA certification are Acetal Copolymer – Acetal Homopolymer, HDPE, UHMW and Nylon, plus many others. Once these steps have been completed, several materials should present themselves as meeting your criteria andphysical property requirement. Unfortunately there is no one perfect plastic that works in all applications. However, for almost every application, there is a material that will work, and work better than most other substrates.
Plastics have been around for over a century now, and are used in almost every industry and application. The problem is that society has made the plastics industry the poster child for waste, trash and pollution. This is unfair, and factually incorrect.
Plastic materials are lighter, cost less to produce, use less electrical power to produce, and are safer for use. It is not new phenomenon that a material or product, once used, gets thrown away. This is the normal life cycle of many materials. Some inexpensive plastic materials used in consumer goods are made to throw away once the item has been purchased. Things like the indestructible packing we fight on kids toys, the cheap plastic sporks from restaurants, the prolific plastic water bottles and of course, the plastic grocery bags. All of these materials are 100% recyclable, the hitch is that it requires a little effort to recycle.
Are Plastic Materials The Cause?
On the positive side, the products that plastic currently replaces are much larger, heavier and generally cost more to produce, and use more energy to produce. This means, that the large amount of plastics that are not being properly disposed of, are replacing much larger quantities of materials that would not be recycled. I still remember times when I was a kid, and seeing tin cans in the lakes and rivers when out fishing. People polluting with their trash is not a new thing, now it is just a different group of materials.
Thermoplastic plastic materials are recyclable, and can be used over and over again. Generally, the recycled product would not be for a Food or Medical application. A common use of recycled plastic is with the collected milk jugs and detergent bottles, both HDPE, can be ground and turned into plastic lumber. The plastic lumber can be used to replace standard wood products for decks and outdoor furniture, and it will last for 15 – 20 years with no maintenance or painting. The cost savings and reduced use of natural resources for this one product can be staggering. The color doesn’t fade, it wood won’t split or crack, and it continues to look good for up to two decades.
Our recent article, “Plastic Material Bad Reputation – How did we get here?“, we discuss the factors that have lead to the ‘throw away’ society that we have become. Much of this bad reputation is for products that are designed as one use and then designed to be thrown away. So, if we are to change the bad reputation, companies need to change this design flaw, and start using materials for applications that can be reused easily.
If we can minimize the use of throw away plastics, and recycle the plastic material once we are done with it, we can help to limit plastic in land fills.
The blame for plastic pollution should be placed…on people. The plastic is not the cause of the problem, it is the litter-bug and irresponsible individuals that trash our planet. How do the plastic bottles and grocery bags end up in the ocean. They certainly don’t throw themselves in to the ocean, it is lack of responsibility and negligent behavior.
It really only takes a couple of seconds to throw something into a recycle bin. Even better would be to reuse the plastic bottles or plastic bags. Plastic materials are not the problem, empathetic people are the problem.
More recycled plastic sheet is needed to fill demand
The plastic industry struggles with bad press over greater amounts of plastic in the land fills and oceans. This is understandable when the quantity of plastic products has skyrocketed. One of the biggest offender is the common shopping grocery sack. Most plastic materials are recyclable, and the demand has grown much faster than the supply, as industrial manufacturers are searching for recycled materials to use in their products.
WASHINGTON (May 22, 10:35 a.m. ET) — With demand for recycled resins continuing to outstrip supply, the voices are getting louder — and more organized — for creating some sort of extended producer responsibility program to increase the recycling of packaging materials, plastics and otherwise.
In the past two months, an alliance of more than 30 public interest groups and other supporting organizations formed the Cradle² coalition to push for public policy changes that would make manufacturers responsible for collecting and recycling the products and packaging they make.
“The broad implementation of EPR is still a long way off,” said Scott Mouw, recycling director for the state of North Carolina. “But these new advocacy groups for EPR are all reacting to the same thing. …(read more here)
The entire plastic supply chain has been affected. We receive calls regularly for our plastic materials, but clients want to know if they can get a recycled plastic sheet version. Most plastics we carry can be recycled, but most don’t make it back into sheets or rods due to FDA and NSF requirements. The most popular plastic we carry that are available as a recycled product are Reprocessed UHMW Sheets and Rods and Repro HDPE. The HDPE is available as post consumer content from milk jugs and laundry soap containers. PTFE sheet is also available as a reprocessed product for applications where the high purity is not critical, just the heat or wear resistance would remain.
Contact us for more information on the recycled plastic materials you may need.
While you can purchase a piece of plastic from many different suppliers, there are some significant differences between these suppliers. Some of the main differences are in the manufacturers and the materials that you get supplied.
We see a wide range of materials and some drastically inferior grades of materials being sold to clients. Some materials have been produced too quickly or cooled too quickly causing a very high stressed plastic piece. These high stressed materials will warp, twist or crack when they get heated or during cutting. This material on the right is a piece of highly stressed Nylon. While cutting the material, our new customer had to stop the saw due to the severe warping and binding of the saw by this material. This new client brought this 24″ long part, and asked if we would cut it for him. We bought this part from him as an excellent example of a high stress plastic. (We did cut a quality piece of material to solve his problem).
One example of differences between manufacturers, is Gehr PVC rod is NSF 51 certified, while Simona PVC rod is not.
Other things you should consider when choosing a quality plastic supplier:
Quality of Materials
Origin of Materials
Huge In Stock Inventory of Plastic Rod
In Stock Materials
Cutting – Converting Services
Longevity – How Long Have They Been In Business (We started in 1975)
Product Knowledge and Experience Equals Quality Plastic Suppliers
We believe that providing quality products is only part of our duty to you. You have intrusted us to help with your requirements, and we believe we should be good stewards of this trust, all part of being a quality plastic supplier. A plastic sheet supplier should advise you if the material you are looking for is the ‘wrong’ material. Acrylic does not do well at 450 degrees. Styrene does not make a good chemical tank. HDPE and PTFE do not bond. These and many more ‘land mines’ are things we help our clients with everyday. We have an experienced client support team (plastic experts), and we value the opportunity to assist our clients with this experience. Go ahead, ask us a question – that is why we have a “Ask A Plasticologist” page on our website.
If you need help, from what are the properties of Acetal, to temperature range on Ultem, please contact us.We look forward to assisting you and all our clients. Feel free to contact us with any questions, concerns or requests – call us at 866-832-9315 or e-mail us here.
Polypropylene Sheet and Sheets come in Natural and White
Let’s start by clarifying what Natural and White means. The natural color of Polypropylene is a translucent straw color, not yellow – not white, more of a very lite translucent – almost transparent beige. The white color is a bright white with a slight blue tint, or blue white. This white color is opaque, and is a white color that blends well with other materials. Polypropylene sheet is also available in the color Black.
Polypropylene sheet materials are available in an opaque black color as well. There is also a grade of Polypropylene sheets that carries a FR – UL 94 V-0 rating. When fabricating a ‘wet bench’ for the electronic industry, the new requirement is FM4910. This new specification is from Factory Mutual Insurance, and the requirements are very stringent. The purpose of this specification is that the FM4910 means it won’t burn, and will put off no toxic fumes or excessive smoke.
This rigid plastic sheet can be cut with standard cutting tools, drilled, routed, machined and processed easily. Clean and sharp tools will provide a clean cut, and occasionally will produce stringy burrs that are easy to remove with standard deburring tools. It fabricates very much like HDPE (High Density Polyethylene Sheet), and has many similar properties. The chemical resistance of Polypropylene approaches the excellent resistance of Dupont PTFE Sheet.
Polypropylene sheet materials have excellent chemical resistance
The main claim to fame for polypropylene in sheet is the excellent chemical resistance. This material is used extensively in the manufacture of chemical tanks. This chemical resistance means also that it can not be bonded together (glues and cements peel right off!), and thus it must be ‘welded’ together for fabrication. The preferred method of welding is a hot air welder – which supplies a fine stream of very hot air on the exact area that you may wish to weld together. This weld, when done properly will yield a very strong bond, and will enable a water tight tank or box to be fabricated.
14 inch Natural Polypropylene Rod produced by Gehr Plastics, the largest domestic plastic rod currently in production.
This great building block material can be used in numerous industrial and chemical type applications. The list of great properties is extensive, here are a few of the highlights:
Self Lubricating and Low Co-Efficient of Friction
High Chemical Resistance
Abrasion, Moisture and Electrical Resistance
Stiffness, Rigidity, or Cut Resistance
Low Specific Gravity (Floats in Water)
Polypropylene sheet and sheeting provide years of use, and can be cleaned with most chemical cleaners. Sheets are available in thicknesses ranging from .032″ – 2.0+ thick, and standard sheet sizes are 48″ X 96″ and 48″ X 120″, plus other sizes can be special run.