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PLASTIC PAIL SELECTION AND USAGE

Return to Pail Selection and Usage Index

Guidelines for the Selection and Use of Plastic Pails:
Gasket Selection

Gaskets are an integral component of a plastic pails package and another area where customers can customize package performance to meet specific product and distribution environment requirements. The following is data to assist in selecting the best gasket for your application.         

My pail is a DOT/UN specification. Does that affect the gasket?
Yes. In a DOT/UN pail, the demands on a gasket are much higher than in a non-regulated pail. The gasket in your UN/DOT pail has been engineered into the overall design of the pail.

Do I need a different gasket material to pass the DOT/UN tests?
Not necessarily. DOT/UN tests are essentially mechanical tests performed with water and air, so chemical compatibility is not an issue. However, DOT/UN pails are often used with more aggressive products, which may require a gasket with greater chemical resistance.  See the following section on material selection.

My pails are used to package food. Do I need a special gasket?
Yes and no. Food pails require a gasket that conforms to Food and Drug Administration regulations. But the most commonly used SBR rubber gaskets already meet these requirements. They are available in either black or white color.

I want to stack my pails as high as possible in my warehouse. Which gasket should I use?
The maximum stacking height of filled pails depends on many factors. Be sure to consult the PSCI website and your pail supplier for stacking and palletizing recommendations.

I need a higher DOT/UN rating for my pail. Can’t I just specify a heavier gasket?
No. Your pail is a highly engineered packaging system. A larger gasket might not be compatible with the geometry of the pail, which can actually result in lower performance.  It will also make the cover more difficult to install. 

I found my product in a chemical compatibility chart, but the only gasket material that’s compatible is Viton®.  What gives?
This is a common misconception. These charts are developed by immersing small pieces of "typical" rubber in the test liquid for an unspecified time. The mechanical properties of the rubber are measured after the test and compared with the pre-test results. The rubber is rated "satisfactory", "fair", or "unsatisfactory".

The problem is that these tests are not "real world". In a pail, the gasket is almost completely retained, so not much of the gasket is exposed to the product. Also, unless the pail is stored or transported on its side or upside down, the gasket is exposed only for a brief time. Consequently, the sealing properties of the gasket in the pail are often unaffected. Whenever possible, gaskets should be evaluated by testing in the pail with the intended product.

Gasket Material Selection
  1. Styrene-Butadiene Rubber (SBR) Ethylene-Propylene Rubber (EPDM) Chloroprene (Neoprene) Rubber (CR) Nitrile Rubber (NR)
  2. Fluorocarbon (Viton) Rubber (FPM)
Styrene-Butadiene rubber is the most commonly used material for container gaskets, used in over ninety percent of all gasketed plastic pails. SBR has very good resilience and tensile strength, low temperature flexibility, and is the most economical. Although it technically has poor resistance to high temperatures, ozone and sunlight, these are conditions that are usually not found in plastic pails. SBR has very little resistance to fats, oils or hydrocarbon solvents. SBR is also readily available in food grade compounds.

Ethylene-Propylene rubber is a distant second to SBR in usage in plastic pails. EPDM has excellent resistance to heat, ozone, and sunlight, and good resistance to acids and alkalies. It has poor resistance to fats, oils and hydrocarbon solvents and is more expensive than SBR.  EPDM is readily available in food grade compounds.

Chloroprene rubber is often referred to as neoprene. CR has excellent resistance to heat, ozone, and sunlight, very good resistance to acids and alkalies, and moderate resistance to fats and oils. It has somewhat better resistance to compression set than SBR. It has poor resistance to hydrocarbon solvents and costs about 50% more than SBR.

Nitrile rubber is used only in a very small number of applications. NR has excellent resistance to fats, oils, acids and alkalies, but it has poor heat and ozone resistance and costs even more than neoprene.

Fluorocarbon rubber (e.g. Viton®) has excellent resistance to oils, fats, hydrocarbon solvents, very good resistance to ozone, and excellent high temperature resistance. In short, the ideal gasket material. Its big drawback, of course, is cost. A typical pail gasket would be over 50 times more expensive than SBR.