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.
Generally, after cleansing you should use the following products (if you use them) in the following order: Treatment (ex. serums, Rx products, acne treatments, etc) Moisturizer Sunscreen Makeup The rule of thumb is to apply lighter feeling products first and heavier, denser products last.However, treatments should always go on first to maximize their penetration and effectiveness. Sunscreen, on the other hand, must always go on after moisturizer but before makeup.unscreen is the next step after moisturizers. For sunscreen, you want to wait 30 minutes after applying to put on anything else so it has time to bind and form a protective UV shield on your face. Finally, all makeup items go on last.