An early stage in the reaction of certain thermosetting resins in which the material is fusible and still soluble in certain liquids.
A chemical additive which speeds up the rate of a chemical reaction and thereby reduces the gel time and cure time. Another term is promoter.
The property of forming a steady or firm attachment.
The failure at the bond line between a substrate and an adhesive; the adhesive separating entirely from the substrate.
The change in properties of a material with time under specific conditions.
The temperature of the surrounding environment.
Curing agent for epoxy resins that is any of a class of ammonia derivatives. They are derived from Ammonia.
The time required for an arc to establish a conductive path in a material.
The intermediate stage during the curing process when the material has gelled but is not fully cured.
A measure of force or pressure required to separate a layer of material from its base.
The voltage at which the insulation between two conductors will break down. See Dielectric Strength.
An instrument for measuring the viscosity of adhesives under standard conditions of temperature.
The final stage in the reaction of certain thermosetting resins in which the material is relatively insoluble and infusible. Certain thermosetting resins in a fully cured state are in this stage.
To form plastic objects by pouring a fluid system into an open mold.
A material which initiates and/or accelerates a chemical reaction but normally does not enter into the reaction.
A scale of temperature which uses 0º and 100º as the freezing and boiling point of water respectively. To convert centigrade to Fahrenheit, multiply by 1.8 and add 32.
A unit of viscosity (with water as the standard = 1.0) for indicating the fluidity or flow property of a liquid at room temperature. 1/100 of a poise.
Formation of a dry powdery chalk-like appearance or deposit on the surface of a material. It is due to a breaking down of the material after being exposed to ultraviolet light, or to other weathering.
A measure of the sensitivity of a material to attack or corrosion by a chemical material.
Classes Of Insulation
Arbitrary temperature ratings based on composition and/or experience with a particular material.
A finishing, protecting, or enclosing layer that seals a component from its immediate environment.
Coefficient Of Linear Thermal Expansion The fractional change in length of a material for a unit change in temperature. Measured in inch/inch/°F or cm/cm/°C.
The internal affinity of a material to itself.
Failure within the adhesive under a stress, resulting in a broken bond with all adherent surfaces still covered with adhesive.
A measure of the resistance of a material to a crushing load. Measured in pounds/square inch or megapascals.
The reciprocal of volume resistivity. Conductance of a unit cube of any material.
A compound resulting from the chemical reaction of two chemically different monomers with each other.
Reacting together large molecules to change the physical properties of material. Cross-linking involves formation of a three dimensional molecular network with thermosetting resins.
The time and temperature necessary for a material to reach most of its optimum properties.
The time for reacting thermosetting plastic or rubber composition to reach certain properties. For materials which react under the conditions of mixing, the start of reaction is the time of initial exposure to the conditions necessary for reaction to occur.
Curing Agent (Hardener)
A cross-linking agent that reacts with a resin to form a copolymer.
The temperature at which a material cross-links or cures.
The weight per unit volume of a material. Measured in pounds/gallon, or kilograms/liter. Specific gravity is the density in kilograms/liter.
The ratio of the capacitance of a material (or insulator) to the capacitance of air. A dielectric constant of 4 means an insulator will absorb 4 times more electrical energy than air.
The maximum electrical voltage which an insulating material can withstand without breakdown (conducting electricity). Expressed in volts/mil.
A reactive or non-reactive additive whose primary function is to lower the viscosity and extend the material to which it was added.
The process of coating or impregnating of insulating materials by immersion into the uncured material.
The measure of the loss of power which takes place in virtually all dielectric materials, usually in the form of heat. It’s expressed as the ratio of the resistive (loss) component of the current to the capacitive component of current and is equal to the tangent of the loss angle.
Application of a clear doming material (urethane or epoxy) to the surface of labels, nameplates or decals for the purpose of creating a clear raised (“domed”) surface. Used to enhance and protect the appearance of these products. (See also “Scripting”)
That property of materials to tend to recover their original size and shape after deformation. If the strain is proportional to the applied stress, the material is said to exhibit Hookean or ideal elasticity.
The increase in length of a material when stress in tension. Measured as a percentage increase over the unstressed material.
The enclosure of an electronic, electrical, or electromechanical device in a resin matrix. Most commonly, the embedding matrix is composed of a thermosetting polymer than can be converted from a liquid to a solid by heat, chemical reaction and/or a combination of these. The device is buried or encased in the liquid, which then forms a protective shell when the liquid hardens.
Enclosing an article in a closed envelope of a material.
A specific type of chemical structure based on ethylene oxide.
The removal of entrained air from an epoxy system by vacuum. Also referred to as degassing.
The amount of heat given off by a chemical reaction, proportional to the mass.
An available or relatively inexpensive compatible material which can be added to a more valuable substance so as to increase the amount of material in useful form. The use of extenders may involve adulteration under some conditions.
The failure at the bond line between substrates and an adhesive; the adhesive separating entirely from the substrate.
Failure within the adhesive under a stress, resulting in a broken bond with all adhered surfaces still covered with adhesive.
The failure of the substrate material itself, upon subjecting bonded adhered surfaces to a stress.
An inert material added to a formulated system to improve properties and/or decrease cost.
Small globular mass which has not blended completely into the surrounding material and is particularly evident in a transparent or translucent material.
The property of a material that extinguishes a flame once the source of heat has been removed.
Ability of a material to withstand failure due to bending.
The propensity of a material to form a gas during cure.
The time it will take a thermosetting material to become solid at a given temperature and mass.
Glass Transition Temperature (Tg)
The temperature at which cured resins undergo a change from a glassy state to a softer more rubbery state.
A material or mixture of substances added to a plastic composition which cross links another material, typically a polymer. See Curing Agent.
Resistance of a material to deformation by indentation. See Shore Hardness.
Heat Deflection Temperature
HTD – The temperature at which a standard test bar will deflect 0.010″ under a static load of 264 psi. A method to approximate Tg.
The ability to withstand shock loading; or, work required to fracture under shock loading a specified test specimen in a specified manner. See IZOD Impact Strength.
To fill the voids of a material with a compound.
The ratio of the direct voltage applied to electrodes in contact with an epoxy system to the total current between them. It is dependent upon both the volume and surface resistance of the epoxy systems. ASTM D257-61.
Izod Impact Strength
The amount of force necessary to fracture a notched piece of plastic with a hammer type impact. Measured in foot pounds/inch of notch. Also known as the brittleness of a material. Brittle materials will have low izod impact values (.15 for example). Tough materials will have high izod impact strengths (.60 for example).
Lap Shear Strength
A measure of adhesive strength when placed between two metal coupons and pulled in a tensile mode.
Meter-mix-dispense equipment. A dispensing machine that meters the proper amount of resin to hardener,mixes the two together in a static or dynamic mixer and dispenses the mixture.
The optimum amount of resin and hardener that gives the desired properties.
Modulus Of Elasticity
The measure of stress to strain in a material that is elastically deformed.
The amount of water a material will absorb under certain conditions.
The ability of a material to resist degradation from moisture in the air or when immersed in water.
Composed of matter or chemicals of hydrocarbon origin.
Uneven surface somewhat resembling an orange peel.
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A high viscosity material that resists flowing on a vertical surface.
A coloring agent.
Highly polymeric materials that deform under stress and temperature. See and .
To unite chemically two or more monomers of polymers of the same kind to form a molecule with higher molecular weight.
Additional time/heat cycles to which a cured thermosetting plastic is subjected in order to enhance the properties.
The amount of time a mixed material may be easily used at a specific temperature. It Is usually measured as the time it takes for a material to double in viscosity.
The process of dispensing an insulating material into a container. Typically, the container remains as an integral part of the unit.
A process for molding in which the shrinkage is minimized by forcing the material under pressure into the mold and gelling it in stages.
A chemical agent used to prevent a material from adhering to a surface such as a mold.
An organic substance of natural or synthetic origin characterized by being polymeric in structure.
The ability of a material to resist passage of electric current through itself or on its surface. The unit of volume resistivity is the ohm-cm, of surface resistivity, the ohm.
A process in which a clear doming material (urethane or epoxy) is applied to labels, decals or nameplates that feature scripted lettering, graphics or symbols. XYZ automation is often used to control the deposition path of the doming material.
The amount of time a material may remain useable in its original containers.
The reading of a material’s hardness on a durometer similar to the Shore A durometer. The scale of 0-100 is used on rigid and semi-rigid materials. Consists of a pin point depression into the material. Both the Shore A and Shore D instruments are made by the Shore Instrument Manufacturing Company, Inc., Jamaica, NY.
Polymeric materials composed of molecules of silicon and oxygen.
A liquid substance which dissolves other substances.
The ratio of the weight of any volume of a mass or substance to the weight of an equal volume of water at given temperature. The specific gravity of a substance times the density of water equals the density of the substance.
Any material on whose surface an adhesive is spread for bonding or coating.
The resistance of a material to the flow of electric current over its surface. Measured in ohms/centimeter
Tensile Shear Strength
See Lap Shear Strength.
The ultimate pulling force required to break a material. Measured in pounds/sq. Inch or megapascals.
See Glass transition temperature
A measure of a material’s ability to conduct heat. Measured in BTU-inch/hours-square foot/°F or calorie-centimeters/second-square centimeters/°C.
See Coefficient of Linear Thermal Expansion.
A plastic which will repeatedly flow under the application of heat and pressure.
A plastic material that is capable of being changed into a non-melting or insoluble product by heat or chemical means.
Describes materials that will not flow unless agitated or forced through an orifice. Shear thinning.
False body. The property of a paste or fluid to thicken or set up to a paste or a semi-gel when allowed to stand. Agitation breaks it down but further standing will again permit a viscosity rise.
A polymeric material that is formed by the use of an Isocyanate base chemical.
A measure of the resistance of a fluid to flow or the internal friction within the body of fluid. Measured in Centipoises or Pascal seconds. See “Common Viscosities.”
The resistance of a material to the flow of electric current through itself. Measured in ohms/centimeter.
The ratio of the weight of water absorbed by a material to the weight of the dry material.
The thorough impregnation of a material by a liquid. The more viscous a fluid, and the higher its surface tension, the more difficult it is for the liquid to “wet” materials. Certain additives can reduce surface tension or viscosity and improve wetting properties, allowing the material to flow out more.
(Work Life) See Pot Life
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