|Glossary of Terms|
Acrylic Adhesive - Adhesives formulated with acrylic polymers. Generally better long-term aging and environmental resistance than rubber.
Adhesion -The molecular force of attraction or bond between any adhesive and the surface with which it is in contact. The strength of the attraction or bond is determined by the surface energy of the material. PSAs' measure of performance is expressed in ounces or pounds per inch width as it is pulled at a 180o angle at the rate of 12 inches per minute, usually off of a polished stainless steel panel.
Contamination - Refers to the presence of dirt, oil, grease, moisture or other loose material on the surface being bonded to which impedes an adhesive tape's contact, thus preventing a good bond.
Double-coated - Adhesive is coated on both sides of a carrier material. This construction is provided on a liner coated on both sides with silicone. Double-coated tapes offer more stability when narrow slitting, add support to otherwise stretchy gasketing materials such as open cell foams, and reduce the chances of over lamination on porous materials. In addition, using a film carrier offers the ability to coat two dissimilar adhesives in a single product. This allows for a permanent/removable system or optimal bonding when dissimilar substrates are involved.
Double-Linered, Double-Coated- Same as above, but provided with a release liner on both sides. The liners are silicon coated on only the side which comes in contact with the adhesive. The second liner requires careful handling to avoid delamination issues due to the memory of the carrier. This "adhesive sandwich" often needs to be supplied on larger diameter cores. Generally is more economical to add a liner during the converting process as opposed to during manufacturing. These products are typically used for die-cut parts.
MVTR - Moisture Vapor Transmission Rate. The term applies to a property of films which allows moisture vapor to migrate through the material. Most commonly used in the medical adhesive industry for wound care devices.
Pattern Coating- Refers to the width and spacing arrangement of adhesive laid down parallel to machine direction, across the width of a pressure-sensitive stock during its manufacture.
Release Liner - A backing coated on one or both sides that protects the adhesive until use. The liner is removed and discarded before application. Most frequently found on double-coated tapes and labels.
Removable Adhesive - A pressure-sensitive adhesive which is characterized by low ultimate adhesion to a wide variety of surfaces.
Rubber-Based Adhesive - Adhesives made from one or more synthetic or natural elastomers and tackifiers. These adhesives are characterized by having higher quick stick and adhesion than acrylics, however, they lack aging and weather resistance. Most cost-effective PSA system.
Shear Adhesion - The ability of a tape to resist slippage under shear stress. It is measured by applying a standard weight on the bottom portion of the tape. Measurement is given in minutes until failure and/or distance slipped.
Silicone Adhesive - Adhesive compounded from silicone polymers. More costly relative to other types of systems with low initial tack and adhesion. Silicone systems are the only type of PSA that will consistently bond to silicone substrates.
Single-Coated, Linered - Adhesive is coated on side of a facestock; the adhesive is protected by a release liner coated on one side with silicone.
Single-Coated, Self-Wound - Adhesive is coated on one side of facestock; the other side is generally coated with silicone to enable tape to unwind easily as there is no later addition of a release liner.
Surface Energy - Determines how well an adhesive "wets-out" or flows uniformly on the surface being bonded to. High surface energy materials, e.g. stainless steel and glass, offer excellent bonding characteristics. Low surface energy materials, e.g. molded polypropylene, resists "wetting-out" and require the use of more aggressive adhesive or a special surface treatment for proper bonding.
Unsupported Transfer Tape - A "film" of unsupported adhesive is coated directly onto a siliconized release liner. The release liner is coated with silicone on both sides to insure that the tape unwinds easily and can be laminated to various substrates. The unsupported construction offers superior conformability to irregular surfaces. Typical uses include nameplate mounting and foam bonding.