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?
Is HDPE Sheet and Acetal Homopolymer Sheet the same?
Here is another popular question asked by our clients. Is HDPE the same as Acetal Copolymer / Delrin Acetal Homopolymer?
No, they are two totally different materials. Although the natural color of both is a milky white to opaque white, and they do look a bit similar, they are not. (HDPE is milky white to almost translucent depending on thickness, and the Acetal materials are a more opaque white to slightly milky – once again depending on thickness . See picture below of .500″ thick samples of HDPE and Acetal sheets)
HDPE and Acetal – Some Differences
The HDPE sheet and rod is a softer material, and is commonly known for its FDA certification and used in numerous food applications, such as: one gallon milk jugs, cutting boards, colored water glasses/cups, and many, many more. While it can be machined, because it is a bit softer and lighter, the tolerances it can be machined to are not very tight. It is not bondable, so it makes a great non-stick surface for sticky foods and adhesives.
The Acetal Copolymer and the premium Delrin® Acetal Homopolymer also have FDA certification, and are used heavily in the food processing industry. This material is a more mechanical material and is used in bearing and wear applications, cams, feeder screws, etc. This material is can be machined to tight tolerances, and will wear for long periods without lubrication. Due to its exceptional wear properties, it is not bondable, thus requiring mechanical fastening or threads to assemble. It has a very low water absorption, and you will find it in your toilet tank as the white moving parts in the filler mechanism. It is an extremely popular material for machinists, as it works much like soft brass.
While HDPE Sheet and Acetal Sheet look similar, they perform quite a bit differently.
While both materials are FDA approved, are machinable and can be used to make rigid wear resistant parts, they are two different resins and have drastically different physical properties. Another major difference is in the weight of these items, HDPE sheet and rod material weighs about 35% less than the Acetal sheet and rod material. Please check the data sheets for more information to assist in proper material selection.Acetal Data Sheet and HDPE Sheet Data
Acetal is commonly known as: Delrin Homopolymer Acetal, Tecaform AH,Ensital, Unital, Pomalux, Ultraform and many more.
HDPE is also known as: Ultraethylux,Densetec, Polystone G, Fortiflex, Versadur, Hostalen, and many more.
Contact us for more details on the HDPE and Acetal families of plastic materials, e-mail us or call 866-832-9315
Topic: HDPE sheet and Delrin Sheet (Acetal Sheet)
Today’s topic is all about industrial plastic sheet materials in flat sheet or sheets. Also known as plate, slab, strip and bar.
Most plastic materials are processed into sheets or rods. Rods are round, sheet is flat, square or rectangular. These two basic shapes are both generally extruded, although sheet can also be compression molded. Almost all plastic raw materials are available in sheet, and in a huge range of sizes. Most materials are available from .063″ to over 4″ in thickness; and some as thick as 8″ (how to measure thickness accurately, use a 6-Inch Digital Caliper with Extra-Large LCD). Sheet sizes vary, but generally most plastics are produced in 48″ X 96″ sheets or larger, but once again this changes with types of materials and thickness desired. We can help with almost any plastic material.
Need Help Picking a Plastic Sheet Material?
Deciding on the proper material for an application is the first step. Start by reviewing our Plastic Materials Selection Guide to help narrow your search. Having the key properties and needs of your project in mind will help you with this step. Also looking at both the pro’s and con’s of a material will assist in this search. Materials with the greatest property range can be extremely expensive, selecting a material that meets your needs and your budget should be considered.
Step two is researching sizes and availability – this is where we can really help. With most of the major manufacturers as partners, we are able to source your parts from many factories. While the quality from most factories is excellent, the variable is standard and custom sheet sizes. We also stock a wide variety of materials in large sheets. One of our many manufacturers is Westlake Plastics. They have been compression molding large sized sheets of many popular plastic resins; these sheets are available in 48″ X 120″ as a standard sheet size in most plastics. They produce these materials from .250″ – 3.0″ thick or thicker. Other manufacturers produce 24″ X 48″ or 48″ X 96″ sheets as standard. Please contact us for specifics on your material selection.
Most of our plastic resins are available as a sheet. This includes some of the most popular plastics, like: Polycarbonate Sheet, Acetal Sheet, PTFE Sheet, Ultem Sheet and dozens more. Sometimes, Plastic sheet is called: Plate, Strip, Bar, Slab, Block or Panel. Please think of these names as being synonyms with Plastic Sheet. Contact us with your special requirements.
In thicker gauges, plastics are frequently referred to as plate, slab or block. And strips or narrow pieces are called bar. A rose by any other name, call it what you will, the plastic starts as a flat sheet from the factory. We can cut them to size or shape. Blanking of sheets to useable sizes is our specialty. Narrow pieces used for long applications are normally called strip. Strip is common in wear type applications.
For a list of materials we have as standard stock materials, check our Plastic Sheets Page. These and many other plastic materials are available, and custom sizes, shapes and colors vary by base material. As a stocking distributor for dozens of major manufactures, we are the West Coasts leading plastic sheet supplier or distributor. If you are in need of some technical assistance go to our Plasticologist page for specific help.
Contact us for more information on plastic sheet materials. Email us or call 866-832-9315
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.
Next time you are cutting vegetables on your cutting board, the material most likely to be used is Polyethylene. Because it is stain, moisture and odor resistant, Polyethylene is a perfect choice. Other cutting boards made out of wood are more susceptible to bacteria and odors because they lack the properties that Polyethylene sheets offer, such as its chemical resistance and FDA approval for food contact. Polyethylene is a very durable and lightweight material that comes in many forms and is a great for a wide variety of applications.
NSF Approved Cutting Boards
The HDPE is available in .500″ thick in several FDA / NSF approved colors, and is great for use in kitchens where cross contamination is a problem.
The Ultimate Cutting Board
Polyethylene has many names. The most common are HDPE, LDPE, and UHMW. The difference has to with the molecular weight and branching which is when a monomer or atom is replaced by a longer chain of polymers (a long repeating chain of atoms). High Density is commonly used for milk jugs and food containers. Low Density is commonly used for bottles and plastic bags. UHMW, which has higher molecular weight (2-6 million) allows for an even transfer over the length of material which makes it stronger and able to be used for bearing applications due to its great wear resistance. Commonly used in the food and dairy industry, UHMW is a great replacement for other materials and solution to many problems. All of these polymers are derived from the same family but all have certain properties that make them a little different. HDPE provides great chemical resistance, with high impact strength and great energy absorption. LDPE has most of the same properties as High Density but is not as dense at 9.15, opposed to HDPE which is 9.34. It also has a lower tensile strength and easier formability.
UHMW is a strong material that has great durability and low co-efficient making it an ideal for sliding applications. Polyethylene offers a wide range of material choices and properties and has great durability that can be suitable for a number of applications. From the food industry to automotive, the kitchen or the warehouse, whatever your Polyethylene needs are; High Density, Low Density or UHMW, Polyethylene is a great choice.
Typical Resin Properties:
General Property
ASTM Test
Typical Value HDPE
Typical Value LDPE
Typical Value UHMW
Specific Gravity
D792
.941 – .965
.91 – .925
.93 – .94
Tensile Strength Yield
D638
3,800 – 5,500
1,400 – 2,000
6,800
Izod Impact – Notched
D256
2.0 – 3.5
>16
No Break
Vicat Softening Temp
D1525
257ºF
219ºF
260
Hardness – Rockwell
D785
D60 -70
D42 – 50
R64
Continuous Use Temp
–
-100 – 180ºF
174ºF
180ºF
Deflection Temp @ 66 psi
D648
171
124
174
Co. Thermal Expansion
D696
7X10-5
4.6 -5.5X10-5
11.0X10-5
Please contact us for more information on FDA and NSF approved plastic materials. Email us here, or call us at: 866-832-9315
