It is sometimes convenient to categorize packages by layer or function: primary, secondary, etc. 1  Primary packaging is the material that first envelops the product and holds it. This usually is the smallest unit of distribution or use and is the package which is in direct contact with the contents.
Sunscreen does not stop working the day after the expiration date. Sunscreen is usually effective for at least three years, which is usually longer than the expiration date marked. What to Look for When You have Allergies or Sensitive Skin. Skin allergies can be a common problem. For individuals with sensitive skin, try physical sunscreens. Physical sunscreen protects your skin by deflecting or blocking the sun's rays, while chemical sunscreens absorb the sun's rays.
A: Expiration dates are often stamped on sunscreen containers to specify the time limit for a productâs stability and efficacy. For optimal sun protection as well as texture, stability, and sterility, use the sunscreen prior to the date listed. If you canât find a date on a new tube or bottle, write the month and year you purchased it in permanent marker on the tube. To test shelf life, manufacturers store a product at 40Â°C with 75 percent humidity; then at 40Â°C with 25 percent humidity; and then test it at 0, 1, 2, and 3 months.