A tackifier increases the stickiness of an adhesive. If an adhesive isn’t sufficiently sticky on contact, tackifiers can be added to make it more functional. These products are used in a variety of compounds and they come in several different families, classified by base ingredients. Most are resins, produced from plant or hydrocarbon sources, that can be used with adhesives designed to perform in hot, wet, or radioactive environments, depending on formulation.
Stickiness, also known as tack, is an important trait in adhesives. These compounds need to be able to cling tightly to surfaces and maintain their adhesiveness as conditions change; bumper stickers used on cars, for instance, can’t have adhesives that become brittle in high heat or start to dissolve in the rain. On their own, adhesive products may not have the necessary traits to perform within an acceptable range, and may require a tackifier to be more useful.
Rosin tackifiers are derived from tree sources, including waste products from paper manufacturing, while hydrocarbon resins are made from petroleum products. A separate group of terpene tackifiers is also available. These tend to be more costly to produce and are less common, except in applications where they perform better than other products. Manufacturers test them to determine their tolerances and find appropriate adhesives to blend them with so they can advise customers on the best options for their needs.
Adhesives may need to stick on contact, including with surfaces that could be hot, cold, or wet. Tackifiers need to be able to interact with heat, water, or radiation, which can be present in the environment or may be part of the adhesive curing process. Different surfaces like plastics, metals, and ceramics also require their own unique formulations to ensure the product sticks; caulking used on windows, for example, cannot start to pull away from the glass or leaks will develop. If the tackifier fails, an adhesive can start to crumble or peel.
The best tackifier can depend on the ingredients in an adhesive and where it will be used. Manufacturers typically offer a range of options and may have advice on specific blends for their customers. It is also possible to develop a new tackifier for a specific application if existing products are not suitable. Some concerns beyond performance in a variety of conditions can include odor, color, and curing time, all of which may play a role in whether a product will work well.