Best Tools To Assist In Your Plastic Sheet Search

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 commonly available. In addition, the chart compares the physical properties of these common plastic materials. Click on picture to access chart.

IAPD Plastic Selection Rectangle 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 Physical Properties Chart, 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 continuous temperature 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 plastics have excellent chemical resistance as evidenced by evaluating the container the chemicals are stored in already. A common 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 carbon black 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 and textures for use in marine, playground and food processing applications. In many plastic applications, a machined part is 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 replacement and identification.

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 other factors in the ‘Strength’ realm, like Notched Izod and Stress Can Cause Your Plastic Part to Bow, Twist and Crackwater 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 a soft and slippery plastic, but will ‘cold flow’ under high pressure, and High Pressure Laminates like G-10 FR 4 sheet can 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, coving material that is either FDA (Food and Drug Administration) or NSF (National UL Ratings for Plastic MaterialsSanitation 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 Delrin – Acetal, HDPE, UHMW and Nylon, plus many others.
Once these steps have been completed, several materials should present themselves as meeting your criteria and physical 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.

Cool Online Tool

There is also an additional tool that can be used to help identify some of these properties quickly, the Gehr Plastic Selector online application.

If you are still in need of assistance in identifying an appropriate plastic material, contact an experienced Plasticologist at Industrial Plastic Supply, Inc. – call 866-832-9315

Also see the article, New Methods To Pick Proper Plastic Sheet Materials, for additional information on this subject.

Google+ Author – Hayden Hess
Topic: Best Tools to Assist In Your Plastic Sheet Search

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FDA – NSF Approved Cutting Boards

HDPE and UHMW Polyethylene Sheets

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 Colored HDPE Cutting Boards NSF approvedcontact. 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 FDA and NSF approved UHMW machined sproketapplications. 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

Google+ – Hayden Hess

Topic: HDPE Cutting Boards – NSF Approved