Velcro® USA uses a "B" indicator on the release liner for Rubber based adhesives. An "R" indicator is used for the Acrylic based adhesives. Both types of adhesive are pressure sensitive, which means that they are applied to an object by pressing it on. Deciding between a rubber or acrylic-based adhesive hook and loop product depends upon the type of material it is being attached to, the environment it will be used in and the situation in which it will be used.
Rubberised tape is a synthetic polymer that is often used in the hook and loop fastening system. It is usually less expensive and has a higher initial tack quality than acrylic-based adhesives, but rubber adhesive is more susceptible to moisture and high temperatures, which may cause it to break down over time. It is also not a good choice for use with solvents or chemicals that can wear away at the rubber. Rubber provides great adhesion on plastic items and in indoor situations where there is less of a chance of drastic temperature changes. It provides an excellent amount of light-duty staying power. Shop for rubber adhesive-backed hook and loop tape here.
Acrylic-based adhesive is a synthetic fiber made from a polymer. In addition to hook and loop fasteners, a wide variety of products are made from acrylic, including textiles and home furnishings. They work well on a wide range of materials such as wood, metal, glass and outdoor and waterproof items. Acrylic adhesive holds up well to moisture and can sustain drastic temperature changes as well as seasonal elements such as ultraviolet light and freezing conditions. It takes about 24 hours for an acrylic-based adhesive to completely bond to a surface. An excellent choice for rugged outdoor conditions and varying temperatures, acrylic is resistant to solvents and chemicals, making it a useful product for the industrial sector. Acrylic adhesive is more expensive than rubber adhesive but has the staying power to provide years of use. Shop for acrylic adhesive-backed hook and loop tape here.