|
Information Page Links:
Featured Adhesive Manufacturers
About Adhesives
Adhesives Terms
Adhesives Associations
Adhesives Resources
Trade Shows
Featured Adhesive Articles
More Articles
|
|
About Adhesives
Adhesive manufacturers and adhesive suppliers offer
a wide assortment of products for temporary and permanent bonding, encapsulating,
laminating and sealing. To buy or have manufactured the most effective
adhesive for a certain situation, consider the type of material to which
it needs to bond and the type of bond strength necessary for the duration
and demands of the application. Searching for the right adhesive can
be quite a task because the kinds are so various and new innovations
are continuously forthcoming.
Adhesives can come as one-part or two-part formulas. Two-part adhesives
consist of two separate components that need to mixed (some come pre-mixed)
or applied to separate adherends and pressed together to create a chemical
reaction leading to their bonding properties. One-part adhesives have
latent bonding properties that are activated in various ways depending
on the type of adhesive. Activation methods for adhesives include heat,
addition or loss of water or a different solvent, pressure and lack of
oxygen, as in anaerobic adhesives.
Adhesives can have differing setting temperatures ranging from above
212 degrees F to below 68 degrees F, depending on how much they need
to be either cooled or dried to harden. For example, hot melt adhesives
are activated to viscous liquid states at elevated temperatures and set
when cooled. Adhesives have various setting speeds, some remaining tacky
for a certain amount of time allowing parts to be assembled. Adhesives
that have residual tack offer repositioning options. Once harden some
adhesives can not be softened with heat; these are thermoset adhesives.
However, some can be softened due to temperature change or moisture contact,
so care must be taken when selecting an adhesive for these more demanding
applications. Adhesives also vary as far as bond strengths. They can
be measured by tensile strength, wet strength, impact strength, fatigue
strength, cleavage strength, peel strength and shear strength.
Adhesive manufacturers and adhesive suppliers can offer products in
the forms of solids (hot melt sticks, powder, granules, pellets, chips,
etc.), liquids, pastes, foams, films or aerosol sprays. Film adhesives
offer a uniform glueline, are activated by heat and/or pressure and come
with or without release paper. Laminating adhesives are common film adhesives.
A gap filling adhesive can be utilized as a sealant because it does not
shrink much when set. Adhesive manufacturers and adhesive suppliers often
sell application products such as hot melt glue guns and dispensers.
Application methods include spreading with a tool or brush, spraying,
dispensing through a nozzle (as in hand-held squeeze bottles, caulking
guns or complex air-actuated or electric-actuated nozzles), roll coating,
transfer printing, screen printing, curtain coating and application as
a solid as with pressure sensitive or heat-activated film adhesives.
Featured
Articles
http://www.specialchem4adhesives.com/resources/latest/displaynews.aspx?id=863
http://pffc-online.com/mag/paper_making_choices_coating
Types of Adhesives
- and acrylate adhesives offer fast bonding at room
temperature and are highly resistant to environmental conditions. They
are able to stick to oily surfaces and many types of materials, including
most metals, plastics, glass, ceramics and wood.
- are industrial spray adhesives that offer convenience
and performance for general purpose, foam and fabric, upholstery, screen
printing, labeling, palletizing, trim and laminating, high bond high
strength, high strength fast tack, pressure sensitive repositionable
and temporary or permanent bond applications.
- cure in the absence of oxygen. Curing is catalyzed
when bonding with surfaces where metallic ions are present.
- –
- , or electrically conductive adhesives, offer electrical
and/or thermal conductivity between components.
- are fast setting adhesives commonly referred
to as “crazy glue.” Only a small amount of these one-component
adhesives is necessary to form a rigid plastic layer that has high
strength.
- , or epoxy resins, are raw materials that can be formulated
to make paints, coatings or adhesives.
- are very strong and highly heat and chemical resistant.
They can be formulated to be either flexible or rigid, transparent
or opaque, fast setting or extremely slow setting, making them appropriate
for nearly any use.
- , or thermal adhesives, are viscous liquids at elevated
temperatures and generally set quickly when cooled. Types include fast
set, delayed set and pressure sensitive and common uses are for bookbinding,
product assembly and box and carton heat sealing.
- are substances that are used for bonding in thin
layers. They come on sheets of release paper that are wound in rolls
to be used in lamination presses or applied by hand with a plastic
squeegee or hand roller. The liner is then removed from the adhesive.
- are a newer form of adhesive technology developed
to offer superior performance compared to acrylic adhesive, which can
be brittle and less reliable. Methacrylates provide good gap fill,
excellent impact resistance, flexibility and peel and shear strengths,
medium to fast curing, and tolerance of dirty surfaces.
- , or UV adhesives, are cured by exposure to ultraviolet
light. These adhesives are commonly used in fiber optics and dentistry.
- bond with a wide range of materials and are tough
and flexible at low temperatures but weaken due to high temperatures
and contact with moisture.
- are used in membrane press operation. They
are heated to the proper temperature for lamination in the press and
then quickly set for the unloading and trimming of the piece.
- react with moisture in the air or the bonding
substrate to form a cured polymer layer with high strength. Silicone
and polyurethane are the most common.
- come as two-part formulas or pre-mixed, which
need to be mixed very well to give the best quality tough yet flexible
bonds that they can. They can form strong bonds to most materials and
are more flexible than epoxies.
- can not be softened with heat once they are set.
Thermoset materials include epoxies, polyesters, silicones, rubbers
and polyurethanes.
- consist of two or more components that react to
become chemically cross-linked. Their higher costs are related to their
extremely high bond strengths and exceptional performance, such as
epoxies, polyurethanes, acrylics, and silicones.
- , or aqueous adhesives, use water as a carrier
or diluting medium. They set when the water evaporates or is absorbed
by the substrate.
|
|