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A-stage- |
The early stage in the reactions
of certain thermosetting polymers wherein the material is still
quite soluble in various liquids and flowable at elevated temperatures;
readily formable into specific configurations. |
|
ABS - |
Acrylonitrile - Butadiene Styrene
Resins - versatile widely employed thermoplastic polymer compositions
with moderate resistance to heat, low temperatures and chemicals;
bonds readily to many different adhesive materials. |
|
Acetal - |
Acetal resins based on formaldehyde
are high performance engineering plastics with superior abrasion
resistance and toughness; may require pretreatments to enhance
adhesion properties. |
|
Accelerators - |
Substances employed to speed up
the cure of adhesives, sealants, potting/encapsulation compounds
and impregnants; See also ‘catalyst’. |
|
Acrylics - |
A family of thermoplastic synthetic
resins based largely on acrylic esters with a wide range of performance
properties; acrylic resins are often recognized for their superior
optical clarity, strength and high durability; acrylic adhesives
are available which feature remarkable adhesion to many different
substrates and quick cure times; limited resistance to elevated
temperatures and/or chemical exposure are factors to be considered
when selecting such adhesives,sealants, etc. for specific applications. |
|
Adhesion - |
The state in which two surfaces
are held together by interfacial forces which may be chemical
or mechanical in nature or both; frequently called bonding. |
|
Adhesive - |
A substance with the capability
of holding two surfaces together by either chemical or mechanical
interfacial forces or combinations thereof; bonding agent. |
|
Adhesive assembly
- |
An adhesive which can be employed
to bond parts together such as in the manufacture of aircraft
and automotive components, electronic circuitry, medical devices,
furniture and many other structures or goods. |
|
Adhesive strength
- |
The strength with which two surfaces
are held together with an adhesive, also known as the bond strength;
quantitative tests are available for measuring the adhesive strength
under various environmental conditions; measured in units such
as psi or N/mm2 |
|
Aqueous - |
Related to or based on water containing
compositions. |
|
Bonding - |
The assembly of materials by means
of adhesives; may be carried out at ambient or at elevated temperatures
for specified time periods. |
|
Bond strength - |
See "adhesive strength".
Specific measurements include the load applied in tension, compression,
flexure, peel, impact or shear needed to break an adhesive assembly
with failure noted in or near the plane of the bond. |
|
B-Stage - |
The intermediate stage in the reaction
of certain thermosetting polymers wherein the material can still
be softened when heated or swelled in contact with certain liquids
but cannot be completely fused or dissolved; B-staged resins
generally permit some degree of formability or shaping into certain
specific configurations. |
|
Break- |
Failure of an adhesively bonded
assembly when subjected to excessive loads and/or hostile environmental
conditions such as exposure to excessively high or low temperatures,
aggressive solvents etc; failures can also occur as the results
of inadequate joint design or contamination of the surfaces to
be bonded by oils, grease, particulates and so on. It can also
result from insufficient adhesive application to a joint. |
|
Cartridge - |
A rigid container employed to store
unmixed adhesive compositions in pre-measured amounts; cartridges
may feature a side-by-side or coaxial configuration. |
|
Catalyst - |
A chemical substance employed to
speed up the cure of adhesives, sealants, potting/encapsulation
compounds and impregnants; see also "accelerator";
frequently used as the "B" component of a two-part
thermosetting adhesive; sealant or potting compound. |
|
C-stage - |
The final stage in the reaction
of certain thermosetting polymers wherein the material becomes
largely insoluble and infusible; the attainment of the C-stage
signals achievement of completeness of the cure of these products
and realization of their optimum strength and other pertinent
performances characteristics . |
|
Composite - |
A material made up of two or more
different substances, each having its own properties, combined
to form a third substance with its own specific performance properties;
thus epoxy or polymer type resins can be combined with glass
or graphite fibers to create higher strength glass or graphite
fiber reinforced laminates with enhanced toughness, dimensional
stability etc. |
|
Crazing - |
Fine cracks that may extend in a
polymer network on or under the surface of or through a layer
of an adhesive or substrate. |
|
Creep - |
Dimensional change that can occur
with time with a material under load, following instantaneous
or rapid deformations especially after repeated cycling; creep
at ambient temperatures is often called cold flow. |
|
Cryogenic - |
Applicable to very low temperature
conditions such as liquid nitrogen and below; usually referred
to temperatures below 100°K. |
|
Curing - |
The process which changes the properties
of a material by chemical reactions; it frequently involves a
physical change from the liquid to the solid state; often called
hardening or setting; fully cured materials exhibit maximum physical,
thermal and chemical properties in use. |
|
Curing Agent - |
See accelerator, catalyst, hardener. |
|
Cyanoacrylates - |
A family of exceptionally fast curing
so called "instant glue" adhesives with the capability
of quick bonding to a wide range of metallic and nonmetallic
substrates; special primers are also available for certain difficult-to-bond
to substrates. |
|
Diluents - |
Ingredients usually added to an
adhesive composition to decrease the concentration of the active
bonding materials so as to achieve enhanced flow properties or
reduce cost. |
|
Drying - |
To change the physical state of
an adhesive on an adherend surface by evaporation of the solvent
components of the adhesive composition; drying can also be accomplished
by absorption of the solvent components on the adherend surface. |
|
Elastomer - |
A polymeric material which at ambient
temperatures can be stretched to at least twice its original
length by a deforming force and then returns to its original
length upon removal of that force; elastomers can be synthetic
or natural materials (rubbers). |
|
Epoxy - |
A most versatile group of thermosetting
polymers for adhesive, sealant, coating, potting/encapsulation,
impregnation and coating uses; can be two component room temperature
curing or one part heat curing compositions; feature high physical
strengths, superior resistance to chemical and/or environmental
damage and excellent dimensional stability; widely employed for
structural adhesive applications and as electrical insulation
materials; special formulations are available which feature high
electrical and/or thermal conductivity; remarkably wide service
temperature range. |
|
Exothermic - |
Chemical reactions which release
heat; the opposite of endothermic reactions which require heat
to proceed. |
|
Extenders - |
Ingredients frequently having some
adhesive property, added to an adhesive composition in order
to reduce the cost of the amount of the primary adhesive component
required per unit of bond area. |
|
Extinguishing - |
See also self-extinguishing. Compounds
having resistance to burning. |
|
Failure, adhesive - |
Breakage of an adhesive bond such
that the separation takes place at the adhesive/adherend interface. |
|
Failure, cohesive - |
Breakage of an adhesive bond such
that the separation takes place within the adhesive bond layer. |
|
Fillers - |
Relatively non-adhesive substances
added to an adhesive composition to improve ease of application
and/or some specific performance property such as strength, durability,
hardness, dimensional stability or other characteristics. |
|
Fillet - |
That portion of an adhesive which
fills the corner or angle formed where two adherends are joined. |
|
Flow - |
Movement of an adhesive compound
during application and the bonding process, prior to the onset
of cure. |
|
FRP - |
Fiber reinforced plastics. |
|
Gelation - |
Description of the process wherein
an initially liquid composition thickens and changes from liquid
to solid state; formation of a solid polymer network from a liquid. |
|
Hardener - |
A substance or mixture of substances
added to an adhesive composition to promote the curing reaction;
hardeners become part of the cured adhesive compound (see also
catalyst) |
|
Inhibitor - |
A substance which is added to slow
down the rate of a chemical reaction; they are at times useful
to prolong the storage or working life of certain types of adhesives. |
|
Impregnation - |
The process of imbedding a reactive
liquid into a porous substrate in order to change its properties. |
|
Joint - |
The location at which two or more
adherends are held together with a layer of adhesive (see also
bond). |
|
Joint, lap - |
A joint made by placing one adherend
partly over another and then bonding together the overlapped
portions. |
|
Joint, starved - |
A joint that has an insufficient
amount of adhesive to produce a satisfactory bond. |
|
Laminate - |
A product made by bonding together
two or more layers of material with adhesive. |
|
Load - |
The amount of force that a body,
joint or board can sustain; the force applied to a body, joint
or bond; |
|
Luer Lock - |
A device used as a connector between
a static mixer and a hose or application tool such as a disposable
needle. |
|
Methacrylates - |
A family of high performance thermoplastics
featuring superior optical clarity, abrasion resistance and good
physical strength properties; the term is also used to describe
certain modified acrylic adhesives. |
|
Modifier - |
Any inert chemical ingredient added
to an adhesive compound that changes its properties (see also
extenders, fillers etc). |
|
Monomer - |
A simple chemical building block
with reactivity to make possible the formation of a polymer. |
|
Motionless mixers - |
Devices which employ passive (unmoving)
means to combine and mix two or more substances; commonly found
attached to cartridge systems or meter-mix equipment; frequently
called static mixers. |
|
Neoprene elastomers - |
Synthetic rubbers with superior
resistance to heat and many aggressive chemicals based on chloroprene. |
|
Nitrile elastomers - |
Synthetic rubbers featuring excellent
resistance to oils, fuels etc. over a wide range of temperatures
based on butadiene acrylonitrile. |
|
Nylon plastics - |
Tough thermoplastics polyamide based
resins with superior physical strength properties, toughness
and environmental resistance, usually employed as molding compounds. |
|
O-ring - |
A circular disc of rubber which
fits snugly around the piston to help maintain a seal between
piston and cartridge wall. |
|
Paste - |
An adhesive composition having the
characteristic plastic-like consistency of a paste i.e. a high
order of yield value compared to a liquid. |
|
Peel strength - |
An adhesive's resistance to be stripped
from a bonded joint, usually with the stripping force applied
at a predetermined angle and rate. |
|
Penetration - |
The entering of an adhesive into
an adherent, measured by the depth of the penetration achieved
in a given time. |
|
Piston - |
A disc which fits tightly into the
back of a cartridge against its content. |
|
Plastic - |
1)A synthetic polymeric material
made up from organic compounds. 2) a malleable consistency material
capable of being pushed into different shapes. |
|
Plasticizer - |
An ingredient incorporated into
an adhesive composition that enhances flow, deformation and flexibility;
the addition of plasticizers also tends to reduce melt viscosity,
tensile strength properties and elastic moduli while increasing
toughness and impact strength. |
|
Plunger - |
A rod or stick which forces the
piston and thus the contents of the cartridge to the front and
through the opening. |
|
Polymer - |
A complex compound made up by the
reaction of simple molecules having functional groups which permit
their combination to proceed to a high molecular weight given
appropriate reaction conditions; polymers may be formed by addition
or condensation reactions; addition polymers include acrylics,
ABS, nylons and styrenics, condensation polymers are epoxies,
phenolics and silicones. |
|
Polymerization - |
The process involving chemical reactions
leading to the formation of the large molecules known as the
high molecular weight materials also called polymers. |
|
Post cure - |
A treatment usually involving the
application of heat which is applied to an adhesive assembly
following initial cure; its purpose is to modify certain specific
joint properties such as heat resistance, chemical inertness
etc. |
|
Polyethylene - |
A family of thermoplastics mainly
based on ethylene monomer widely used in injection molding; extrusion
and calendering processes to produce various plastic products
including also films, sheets and fibers. |
|
Polypropylene - |
A family of thermoplastic products
mainly based on propylene monomers; they generally feature a
higher degree of heat resistance and enhanced stiffness compared
to polyethylene plastics. |
|
Polystyrene - |
A group of commodity plastics produced
chiefly of styrene monomers; easy processability especially popular
for manufacturing injection molded parts at moderate cost. |
|
Polyurethane - |
A family of rigid and flexible plastics
characterized by the utilization of the urethane group in their
manufacture; many polyurethane products exhibit high flexibility
and abrasion resistance after cure; special polyurethane based
adhesive formulations are available. |
|
Pot life - |
The period of time an adhesive or
potting compound remains useful after adding an accelerator,
catalyst or exposure to curing conditions. |
|
Potting - |
The process of filling a cavity
or space containing usually electronic or electrical components
in order to protect them from vibration, shock and/or environmental
hazards such as moisture, aggressive chemicals such as fuels
and lubricants, heat etc. |
|
Primer - |
A formulated coating applied to
a surface prior to the application of an adhesive in order to
enhance the strength of the bond. |
|
PVC - |
Polyvinylchloride; polymer family
based on vinyl chloride monomer used in diverse applications
such as flexible films for packaging or rigid pipe. |
|
Resin - |
1) a solid, semi-solid or pseudo
solid organic material with no definite melting point usually
comprised of high molecular weight material; when subjected to
stress a resin typically tends to flow; 2) in adhesives, sealants,
etc., resins are the basic raw materials from which these compositions
are made. |
|
Rheology - |
The study of the flow properties
of different materials especially of non-newtonian liquids and
plastics; non-newtonian materials are substances where the flow
is not proportional to the stress applied. |
|
Rosins - |
Resins obtained as a residue from
the distillation of turpentine derived from the sap of pine trees
(gum resin) or from an extract of the stumps and other parts
of the tress (wood resins). |
|
Sag - |
A decrease in the thickness of a
polymer section. |
|
Self-extinguishing - |
See also extinguishing. Compounds
having resistance to burning. |
|
Setting - |
The hardening or solidification
of an initially liquid plastic material by chemical and/or physical
action. |
|
Shear strength - |
The ability of a plastic material
to withstand shear stresses. |
|
Shortness - |
A qualitative term describing the
characteristic of a polymeric material that does not string or
otherwise form filaments or threads during application. |
|
Silicones - |
A family of polymeric materials
containing the Si-O chemical group in their structure; the most
widely used silicones are elastomeric adhesives and sealants
capable of service over the exceptionally wide temperature range
of –100°F to over 500°F. Both one and two component
silicone compounds are available. |
|
Solids content - |
The percentage by weight of nonvolatile
material in an adhesive or sealant. |
|
Spread - |
The quantity of adhesive per unit
joint area applied to an adherend, generally expressed in pounds
of adhesive per thousand square feet of joint area. |
|
Squeeze out - |
The amount of adhesive pressed or
squeezed out at the bond line of a joint due to pressure applied
to the adherends. |
|
Substrate - |
The basic surface upon which the
adhesive is applied and to which it is expected to adhere. |
|
Surface preparation - |
Physical and/or chemical pretreatments
to enhance the adhesive strength of an adhesive to be applied
to a specific surface. |
|
Tack - |
Adhesive "stickiness"
on an adhesively coated surface that is to yet not completely
dried; the property of an adhesive that permits it to form a
bond of measurable strength immediately after the adhesive and
the adherends have been brought into direct contact by application
of low pressure. |
|
Tensile strength - |
The maximum stress a material can
be subjected to without tearing when stretched under tensile
load. |
|
Thermoplastic - |
Polymeric materials which will repeatedly
soften and flow as the temperature is increased and harden as
the temperature falls. |
|
Thermosetting - |
Polymeric materials which harden
when exposed to high temperatures and pressures but cannot be
softened or re-melted upon further heating; the hardening of
polymeric materials upon heating is due to a largely irreversible
chemical reaction. |
|
Thinners - |
Volatile liquids added to adhesives
to modify their consistency and enhance flow. |
|
Thixotrophy - |
The property of certain adhesive
compositions to thin upon isothermal agitation and to thicken
upon subsequent resting i.e. cessation of the agitation. |
|
Viscosity - |
The resistance of a fluid to flow;
the ratio of shear stress between laminae of moving fluid and
the rate of shear between these laminae. |
|
Wetting - |
The coating of a substrate surface
with an adhesive. |
|
Wicking - |
The flow of an adhesive into a tightly
restricted opening. |
