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Pressure-sensitive adhesive (PSA, self-adhesive, self-stick adhesive) is a type of nonreactive adhesive which forms a bond when pressure is applied to bond the adhesive with a surface. No solvent, water, or heat is needed to activate the adhesive. It is used in pressure-sensitive tapes, labels, glue dots, stickers, sticky note pads, automobile ...
A typical PSA tape consists of a pressure-sensitive adhesive (the sticky part of the tape) coated to a backing material. To prevent the adhesive from sticking to the backing when wound in a roll, a release agent is applied to the backing or a release liner is placed on the adhesive. Sometimes a primer is coated between the adhesive and backing ...
Chemical structure of ethyl cyanoacrylate, the precursor to many commercial adhesives. The most common monomer is ethyl cyanoacrylate.Several related esters are known. To facilitate easy handling, a cyanoacrylate monomer is frequently formulated with an ingredient such as fumed silica to make it more viscous or gel-like.
Pressure-sensitive tape or pressure-sensitive adhesive tape (PSA tape) is an adhesive tape that sticks when pressure is applied without the need for a solvent (such as water) or heat for activation. It is also known in various countries as self-stick tape , sticky tape , or just adhesive tape and tape , as well as genericized trademarks , such ...
The degree of polymerization of polyvinyl acetate is typically 100 to 5000, while its ester groups are sensitive to base hydrolysis and slowly convert PVAc into polyvinyl alcohol and acetic acid. The glass transition temperature of polyvinyl acetate is between 30 and 45 °C depending on the molecular weight.
The bonding temperature is lower than with most other HMAs, only about 50 °C (122 °F) to 70 °C (158 °F), when the adhesive behaves as a soft rubber acting as a pressure-sensitive adhesive. The surface wetting in this amorphous state is good, and on cooling the polymer crystallizes, forming a strong flexible bond with high cohesion.
However, pressure-sensitive adhesives used in double-sided adhesive tapes, rapidly curing "superglue" cyanoacrylate, and many light-curing adhesives do achieve significant initial strength after completion of the joining process or very shortly thereafter, although not their ultimate strength required for further processing of the glued assembly.
Silicone rubber–based pressure-sensitive adhesives require special tackifiers based on "MQ" silicate resins, composed of a monofunctional trimethyl silane ("M") reacted with quadrafunctional silicon tetrachloride ("Q").