Wet strength is a term that is used in the paper industry to describe the ability of a paper product to withstand damage when it is moistened. All types of paper products, ranging from tissue paper used in gift wrapping to brown paper bags, are subjected to testing to determine how well the products hold up when introduced to some sort of liquid or moisture. Standards are set for different types of products, based on the chemicals used to strengthen different paper compounds and configurations for use in the manufacture of those products.
Typically, wet strength is presented as a percentage of the dry strength of a paper product. This means that when wet, the product should still be able to hold up to the same type of load or stress, up to a certain percentage. With many common household paper products the industry standard for wet strength is in the range of 10% to 15% of the dry strength.
Measuring wet strength is important for a couple of reasons. One has to do with complying and possibly exceeding industry standards. This is especially important since those standards are usually set in order to meet minimum governmental requirements for strength and durability for various types of paper products. By testing how the paper functions when subjected to a certain amount of moisture, it is possible to determine if the strength is sufficient to meet those standards and can reasonably be considered safe for use.
Another reason why measuring wet strength is so important has to do with the generation of sales and building a reputation for quality among consumers. Since consumers will want to receive the most quality possible for the money they spend, this means that products such paper towels for use in the kitchen will be judged on factors such as absorbency and the ability to remain intact during use. Towels that hold up well when used for cleaning up spills, wiping counters, or cleaning windows are more likely to attract a loyal client base based on their durability.
In order to enhance wet strength, manufacturers will often add chemicals and other additives during the production process. A popular option with some types of paper products is to add an amount of resin to the paper. At other times, treating the exterior of the product with some sort of film or sealant will also help to add to the overall durability of the product.