What does the term “Shelf Life” of a material mean?
Posted on 7/28/2014
The shelf life of a material in its liquid state refers to how long it can sit on a shelf before it begins to lose its ability to function normally or sets up entirely in the container. You should know how long you can expect a material to last on the shelf to protect your material investment.
Relative humidity and temperature are variables that will affect the shelf life of Smooth-On rubbers, plastics, foams, Matrix products, epoxies, etc.
Shelf Life – Urethane Rubber, Plastic or Foam In Unopened Containers
Properly stored in a low humidity environment and at room temperature (73°F/ 23°C), urethane rubber, plastics and foams will have a shelf life of 1 year from date of manufacture in unopened containers.
Shelf Life – Urethanes After Containers Have Been Opened
The shelf life of unused product in containers that have been opened depends on exposure to ambient moisture in the air. The Part A side (Yellow Containers) is the moisture sensitive side of urethane compounds, and liquid material exposed to high-humidity environments can become moisture contaminated in a matter of hours. This moisture contamination may result in the urethane system bubbling or foaming when Part A is mixed with Part B.
Urethane Rubber – Unused Part A product exposed to humidity will begin to turn from liquid to solid in as little as a few hours. Part A exposed to relatively low levels of humidity will last two to three months in the container before showing signs of moisture contamination.
Limited Shelf Life Of Urethanes – What Can You Do?
Make sure you securely seal the Part A container immediately after dispensing each time.
Your Best Bet – If using urethanes, use what remains as soon as possible once containers have been opened.
Extending The Shelf Life Of Unused Urethanes – After dispensing Part A into a measuring container, spray XTEND-IT Dry Gas Blanket (available from Smooth-On or your Smooth-On distributor) into the container before securely resealing.
XTEND-IT will effectively double the shelf life of the remaining product by neutralizing any moisture-laden air that remains in your container. Follow directions before using.
Nitrogen will have the same effect, but is usually only available in large cylinders; very cost effective, but suitable only for industrial or production environments.
Shelf Life -Silicone Rubber
Properly stored at room temperature (73°F/ 23°C), silicone rubber will have a shelf life of 6 months from date of manufacture as determined by the lot number that can be found on the label of Part A or Part B. You can contact Smooth-On with these numbers to determine when the product was made.
Important – Elevated temperatures will drastically reduce the shelf life of silicone rubber. For example, silicone rubber stored at 80°F / 27°C will have a shelf life of about six months. Material stored at 100°F / 38°C will have a shelf life of about two months.
Shelf Life – Polymer Modifiers for Gypsum & Concrete
DuoMatix G, C and Matrix NEO – Properly stored at room temperature
(73°F/ 23°C), Matrix products will have a shelf life of 1 year from date of manufacture as determined by the lot number that can be found on the label of the liquid latex componenet. You can contact Smooth-On with these numbers to determine when the product was made.
Important – The latex component of the Matrix products must not be exposed to temperatures below 35°F / 1.7°C. Product that was allowed to freeze is no longer usable and should be disposed of.
Shelf Life – Rubber / Plastic Accelerators, SO-Strong Color Tints, Silc Pig Color Pigments and other accessories – at least 1 year from date of manufacture.
Shelf Life – Epoxy Adhesives – One year from date of manufacture.
Shelf Life – Powder Fillers – at least 1 year from date of manufacture.
Important: Keep powder fillers dry.
When Was A Material Manufactured? After locating the lot number on the label of Part A or Part B. You can contact Smooth-On with these lot numbers to determine when the product was made.
The FAQ list is offered as a guideline and offers possible solutions to problems encountered during mold making and casting. No warranty is implied and it is up to the end user to determine suitability for any specific application. Always refer to the provided Technical Bulletins (TB) & Material Safety Data Sheets (MSDS) before using any material. A small scale test is suggested to determine suitability of any recommendation before trying on a larger scale for any application.