Pressure sensitive adhesives (PSAs) are commonly used in the tape and label markets. Designed for either permanent or removable applications, PSAs are usually based on elastomers compounded with tackifiers. Gain insight into the importance of tackifiers in PSA formulation, including their function and when they are used.
What are Tackifiers?
As noted in ASI Magazine, tackifiers are chemical compounds that help balance PSAs’ adhesive and cohesive properties by increasing their peel and tack. With low molecular weight, they raise the PSA’s overall glass transition temperature and possess high viscoelastic properties. This enables them to promote specific adhesion and lower the softening point of the polymer system.
Types of Tackifiers
Tackifiers are divided into three main groups:
- Rosin esters: These resins impart exceptional tack and are derived from tall oil rosins, gum rosins and wood rosins.
- Hydrocarbon resins: Able to offer improved heat and UV stability, hydrocarbon resins are the most popular type.
- Terpene resins: Possessing a high amount of biorenewable content, terpene resins can impart excellent heat resistance.
When are Tackifiers Used?
While tackifiers are often used in PSA formulation, they are not always required. For example, acrylic-based PSAs may not contain a tackifier depending on the desired performance properties. However, many rubber-based hot melt PSAs do need a tackifier in order to improve their ability to bond to different substrates.
Bostik formulates smart adhesives for many tape and label applications. Contact us for more information on how our adhesives offer the ideal level of tack. To stay up-to-date on industry news and information, sign up for our newsletter.