Plain and simply, tensile strength is the ability of a material to resist a direct pull. When referring to ultimate tensile strength, it is the maximum stress that can be withstood before breaking. Commonly the tensile strength is expressed in pounds per square inch.
Higher tensile strength is generally preferred for a variety of packaging products. When packaging heavier products a packing tape with higher tensile strength is preferred to help ensure a better seal. The same goes for companies shipping heavier products by the pallet load. A stretch film with higher tensile strength will reduce shipping damages and increase load stabilization.
The elongation of a material refers to the difference of length between an unstretched tensile-strength sample and the breaking point length. High elongation is great for stretch films and helps to secure and unitize a load. It is also important for a stretch film to have adequate tensile strength for the load it is securing.
Next post we will discuss tear strength and impact strength.
Packaging Blog 
Is there a calculation method to determine a nominal film strength for securing pallet loads of product
?
Steve,
Thank you for contacting us. Due to the shapes and sizes of products being wrapped it is difficult to have a set nominal formula for determining the stretch film strength. Please reference our Stretch Wrap 101 information page below to view a baseline chart of where to start in thickness. The chart addresses the the weight of the pallet and the shape of the objects on the pallet.
https://uspackagingandwrapping.com/stretch-wrap-101.html