Following things need to be considered for label printing validation:
1. Print quality and durability (Printability of the design, Computer printer selection, Abrasion resistance; preprint and imprint, Chemical and solvent resistance)
2. Adhesive properties (Adhesive composition, e.g. hot melt, emulsion acrylic, etc., Adhesive initial tack and ultimate bond, Substrates adhered to and their shape, Application temperature, Operating temperature, Sterilization environment
3. Environmental conditions (Package composition, Shipping method, and conditions, Storage conditions and length of storage, Chemical resistance)
Here is the proposed plan:
1. Adhere samples to appropriate substrates at accepted sample size.
2. Peel tests after 24-72 hours
3. Temperature and humidity conditioning
4. Visual inspection and peel tests
5. Abrasion testing
6. Sterilization and final package tests
7. ‘Shake, rattle, and roll’ tests
Tests that can help you are:
- ASTM D3330, Peel adhesion of PS material
- ASTM D5264, Sutherland abrasion and smudge resistance test
- ASTM F1319, Crockmeter abrasion and smudge resistance test
- ASTM F2252, Ink adhesion tape test
- ASTM F 2250, Chemical exposure, inks & coatings
- ASTM D4169, Distribution testing, “Shake, rattle, & roll”.
- ASTM F1980, Accelerated aging
However, with regard to the need for process validation, the label printing operation can be rendered "non-special" since the process output is fully verifiable through subsequent inspection.