Pressure sensitive adhesive

Pressure sensitive adhesive

Pressure sensitive adhesive (PSA, self adhesive, self stick adhesive) is adhesive that forms a bond when pressure is applied to marry the adhesive with the adherend. No solvent, water, or heat is needed to activate the adhesive.It is used in pressure sensitive tapes, labels, note pads, automobile trim, and a wide variety of other products.

As the name "pressure sensitive" indicates, the degree of bond is influenced by the amount of pressure which is used to apply the adhesive to the surface.

Surface factors such as smoothness, surface energy, removal of contaminants, etc. are also important to proper bonding.

PSAs are usually designed to form a bond and hold properly at room temperatures. PSAs typically reduce or lose their tack at cold temperatures and reduce their shear holding ability at high temperatures: Specialty adhesives are made to function at high or low temperatures. It is important to choose an adhesive formulation which is designed for its intended use conditions.

tructural and pressure sensitive adhesives

Adhesives may be broadly divided in two classes: structural and pressure sensitive. To form a permanent bond, structural adhesives harden via processes such as evaporation of solvent or water (white glue), reaction with radiation (dental adhesives), chemical reaction (two part epoxy), or cooling (hot melt). In contrast, pressure sensitive adhesives (PSAs) form a bond simply by the application of light pressure to marry the adhesive with the adherend. Pressure sensitive adhesives are designed with a balance between flow and resistance to flow. The bond forms because the adhesive is soft enough to flow, or wet, the adherend. The bond has strength because the adhesive is hard enough to resist flow when stress is applied to the bond. Once the adhesive and the adherend are in proximity, there are also molecular interactions such as van der Waals forces involved in the bond, which contribute significantly to the ultimate bond strength. PSAs exhibit viscous and elastic properties, both of which are used for proper bonding.

Applications

Pressure sensitive adhesives are designed for either permanent or removable applications. Examples of permanent applications include safety labels for power equipment, foil tape for HVAC duct work, automotive interior trim assembly, and sound/vibration damping films. Some high performance permanent PSAs exhibit high adhesion values and can support kilograms of weight per square centimeter of contact area, even at elevated temperature. Permanent PSAs may be initially removable (for example to recover mislabeled goods) and build adhesion to a permanent bond after several hours or days.

Removable adhesives are designed to form a temporary bond, and ideally can be removed after months or years without leaving residue on the adherend. Removable adhesives are used in applications such as surface protection films, masking tapes, bookmark and note papers, price marking labels, promotional graphics materials, and for skin contact (wound care dressings, EKG electrodes, athletic tape, analgesic and transdermal drug patches, etc.). Some removable adhesives are designed to repeatedly stick and unstick. They have low adhesion and generally can not support much weight.

Manufacture

Pressure sensitive adhesives are manufactured with either a liquid carrier or in 100% solid form. Articles such as tapes and labels are made from liquid PSAs by coating the adhesive on a support and evaporating the organic solvent or water carrier, usually in a hot air dryer. The dry adhesive may be further heated to initate a crosslinking reaction and increase molecular weight. 100% solid PSAs may be low viscosity polymers that are coated and then reacted with radiation to increase molecular weight and form the adhesive (radiation cured PSA); or they may be high viscosity materials that are heated to reduce viscosity enough to allow coating, and then cooled to their final form (hot melt PSA).

Industry associations

Industry associations dealing with pressure sensitive adhesives include
* [http://www.astm.org ASTM]
* [http://www.pstc.org PSTC (Pressure Sensitive Tape Council)]
* [http://www.afera.com Afera]
* [http://www.tlmi.com TLMI]
*JAPMA
* [http://www.ascouncil.org ASC (Adhesives and Sealant Council)]

ee also

* Pressure sensitive tape
* Post-it note
* Rheology
* Self-adhesive stamp
* Viscoelasticity

Further reading

* "Pressure-Sensitive Adhesives and Applications", Istvan Benedek, 2004, ISBN 0824750594
* "Pressure Sensitive Adhesive Tapes", J. Johnston, PSTC, 2003, ISBN 0972800107
* "Pressure Sensitive Formulation", I. Benedek, VSP, 2000, ISBN 9067643300

"'


Wikimedia Foundation. 2010.

Игры ⚽ Поможем сделать НИР

Look at other dictionaries:

  • pressure sensitive adhesive — Type of adhesive that retains its tack or stickiness even after complete release of the solvent …   Dictionary of automotive terms

  • Pressure sensitive — may refer to:* Pressure sensitive adhesive * Pressure sensitive tape * Pressure pad * Piezoelectric sensor * the force with which a key is held after initial impact (see keyboard expression) …   Wikipedia

  • Pressure sensitive tape — [ thumb|Duct tape is a PSA tape which is hand tearable yet strong enough for many common uses.] Pressure sensitive tape, PSA tape, Adhesive tape, Self stick tape, Sticky tape consists of a pressure sensitive adhesive coated onto a backing… …   Wikipedia

  • pressure-sensitive — | ̷ ̷ ̷ ̷| ̷ ̷( ̷ ̷) ̷ ̷ adjective : responsive to pressure : adhering or sealing under the influence of pressure alone pressure sensitive adhesives are normally used in the form of adhesive tapes V.N.Morris, C.L.Weidner, & N. St. Landau …   Useful english dictionary

  • Adhesive tape — can be one of many varieties of backing materials coated with an adhesive.Several types of adhesives can be used:Pressure sensitive tapePressure sensitive tape, PSA tape, Self stick tape, Sticky tape consists of a pressure sensitive adhesive… …   Wikipedia

  • adhesive tape — n tape coated on one side with an adhesive mixture esp one used for covering wounds * * * [USP] a strip of fabric and/or film evenly coated on one side with a pressure sensitive, adhesive mixture, the whole having high tensile strength, used for… …   Medical dictionary

  • Adhesive — Glue redirects here. For other uses, see Glue (disambiguation). For the band, see Adhesive (band). Nitrocellulose adhesive outside a tube An adhesive, or glue, is a mixture in a liquid or semi liquid state that adheres or bonds items together.… …   Wikipedia

  • adhesive bandage — [USP] a sterile compress of layers of gauze or other material, affixed to a fabric or film coated with a pressure sensitive adhesive …   Medical dictionary

  • adhesive absorbent dressing — a sterile individual dressing consisting of a plain absorbent compress affixed to a film or fabric coated with a pressure sensitive adhesive substance …   Medical dictionary

  • adhesive — adhesively, adv. adhesiveness, n. /ad hee siv, ziv/, adj. 1. coated with glue, paste, mastic, or other sticky substance: adhesive bandages. 2. sticking fast; sticky; clinging. 3. Physics. of or pertaining to the molecular force that exists in the …   Universalium

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”