Glossary M - Z

 M Through Z

M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z


Matrix - The part of an adhesive which surrounds or engulfs embedded filler or reinforcing particles and filaments.

Mega - Prefix meaning one million (M).

Micro - Prefix meaning one millionth part (m).

Milli - Prefix meaning one thousandth part (m) (10-3).

Modifier - Any chemically inert ingredient added to an adhesive formulation that changes its properties.

Moisture Content - Percent moisture content is equal to the weight of water divided by the weight of bone-dry wood x 100.

Moisture Meter - A small electronic device designed to determine the moisture content of wood stock.

Monomer - A relatively simple compound which can react to form a polymer.

MSDS - Material Safety Data Sheet.

Mucilage - An adhesive prepared from a gum and water. Also in a more general sense, a liquid adhesive which has a low order of bonding strength.

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Nano - Prefix meaning one-billionth.

NIOSH - National Institute of Occupational Safety and Health.

Nip Roll - A pressure system designed to apply a large amount of pressure for an instant. This system is frequently used for hot melt, fast-set adhesives, or contact cements.

Non-porous substrate - A substrate that is not permeable by air, water, etc.

Nonflammable - Incapable of being easily ignited or burned.

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Open Assembly Time - Period of assembly time when the adhesive film is exposed to the air.

Open time - The time that the glue may be left open to the air after application. Same as working time. Same as open assembly time.

Open Time - Alternate term for Assembly Time - The time period from the application ot the adhesive until the final application of pressure.

OSHA - Occupational Safety and Health Administration.

Oxygen bomb test - A special aging test given to adhesives. Five hundred hours exposure to the condition in this test generally indicates whether a product will provide a good deal of service over a long range period of time.

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Paste - An adhesive composition having a characteristic plastic-type consistency, that is, a high order or yield value, such as that of a paste prepared by heating a mixture of starch and water and subsequently cooling the hydrolyzed product.

Peel test - A test of an adhesive using one rigid and one flexible substrate. The flexible material is folded back (usually 180) and the substrates are peeled apart. Strength is measured in pounds per inch of width.

PEL - Permissible Exposure Limit.

Percent Solids - The percentage of non-volatile material contained in a liquid.

Percent Volatile - Percentage of a liquid or solid by volume that will evaporate at ambient temperature.

Permanent set - The amount of deformation that remains in an adhesive after removal of a load.

pH - Value that represents the acidity or alkalinity of an aqueous solution.

Phenolic resin - A thermosetting resin. Usually formed by the reaction of a phenol with formaldehyde.

Physical State - The condition of a material - solid, liquid or gas at room temperature.

Pico - Prefix meaning one trillionth.

Pitch - The residue which remains after the distillation of oil and so forth from raw petroleum.

Plasticity - A property of adhesives that allows the material to be deformed continuously and permanently without rupture upon the application of a force that exceeds the yield value of the material.

Plasticizer - A material incorporated in an adhesive to increase its flexibility. The addition of the plasticizer may cause a reduction in melt viscosity, lower the temperature of the second-order transition, or lower the elastic modulus of the solidified adhesive.

Polymer - A compound formed by the reaction of simple molecules having functional groups that permit their combination to proceed to high molecular weights under suitable conditions. Polymers may be formed by polymerization (addition polymer) or polycondensation (condensation polymer). When two or more monomers are involved, the product is called a copolymer.

Polymerization - Chemical reaction in which one or more small molecules combine to form larger molecules.

Polyvinyl acetate (PVA) glue - Any glue consisting chiefly of polyvinyl acetate polymer. This category includes both traditional white glues and yellow aliphatic resin glues. Although PVA glues can vary in strength, flexibility, water resistance, heat resistance and sandability, they are generally non-toxic. All PVA glues are prone to "creep" or slowly stretch under long term loads, and are not recommended for structural applications.

Porous substrate - A substrate that is permeable by air, water, etc.

Post cure, noun - A treatment (normally involving heat) applied to an adhesive assembly following the initial cure to modify specific properties.

Post cure, verb - To expose an adhesive assembly to an additional cure, following the initial cure, for the purpose of modifying specific properties.

Pot life - The useable life of a synthetic resin mix after a catalyst or hardener has been added.

PPE - Personal Protective Equipment.

PPM - Parts per million.

Press time - The period required for a joint to be held under pressure.

Primer - A coating applied to a surface, prior to the application of an adhesive, to improve the performance of the bond.

psi - Pounds per square inch.

Pyrometer - One of several devices designed to measure surface temperature.

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Q    No defined terms


Reactive Material - A chemical substance or material that will vigorously polymerize or decompose.

Reactivity - Tendency of a substance to undergo a chemical reaction with itself or another material with the release of energy.

REL - Recommended Exposure Limit set by NIOSH.

Release paper - A sheet, serving as a protectant and/or carrier for an adhesive film or mass, which is easily removed from the film or mass prior to use.

Resin - A solid, semisolid, or pseudosolid organic material that has an indefinite and often high molecular weight, exhibits a tendency to flow when subjected to stress, usually has a softening or melting range, and usually fractures conchoidally.

Resistance - The opposition to current flow through a material measured in Ohms.

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SARA - Superfund Amendments and Reauthorization Act.

Self-vulcanizing - Pertaining to an adhesive that undergoes vulcanization without the application of heat.

Sensitization - A state of immune response in which further exposure elicits an immune or allergic response.

Set - To convert an adhesive into a fixed or hardened state by chemical or physical action, such as condensation, polymerization, oxidation, vulcanization, gelation, hydration, or evaporation of volatile constituents.

Set Time - The period of time required to attain handling strength.

Shelf life - The period of time, usually beginning with the date of manufacture, during which a stored adhesive will remain effective or useful. Same as storage life.

Shrinkage - Percentage weight loss under specified conditions.

Solids content - The percentage by weight of the non-volatile matter in an adhesive.

Solvent - Liquid in which another substance can be dissolved.
Specific Gravity - A dimensionless unit of density in which the weight of a known volume of a material is divided by the weight of an equal volume of water.

Specific Heat - The quantity of heat needed to raise the temperature of a mass of material as compared with the same amount of water.

Specific Width - Stock that is ripped to a rough width specified on the route sheet. Used as a dimension part in the furniture being manufactured.

Speed of Set - The rate at which an adhesive attains handling strength

Speed of set test - A series of tests run to determine how fast a given glue can build strength under ideal conditions.

Spread - The quantity of adhesive per unit joint area. Single spread refers to application of adhesive to only one substrate of a joint. Double spread refers to application of adhesive to both substrates of a joint.

Square - A face glued construction that is approximately squared in cross section that will be turned on a lathe.

Squeeze out - Adhesive pressed out at the bond line due to pressure applied on the substrates.

Stability -The ability of a material to remain unchanged.

STEL - Short term exposure limit.

Stray-field heating - Radio Frequency curing system in which both electrodes are on the same side of the glue joint. Stray field heating is commonly used in the "hand held" units.

Strength, dry - The strength of an adhesive joint determined immediately after drying under specified conditions or after a period of conditioning in the standard laboratory atmosphere.

Strength, wet - The strength of an adhesive joint determined immediately after removal from a liquid in which it has been immersed under specified conditions of time, temperature, and pressure.

Stress - Force per unit area, usually expressed in pounds per square inch (psi).

Stress relaxation - Reduction in stress in a material that is held at a constant deformation for an extended time.

Stringiness - The property of an adhesive that results in the formation of filaments or threads when adhesive transfer surfaces are separated.

Structural Adhesive - A bonding agent used for transferring required loads between substrates exposed to service environments typical for the structure involved.

Substrate - A material upon the surface of which an adhesive-containing substance is spread for any purpose, such as bonding or coating. A broader term than adhered.

Surface preparation - A physical and /or chemical preparation of a substrate to render it suitable for adhesive joining. Same as substrate preparation or prebond preparation.

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Tack - The property of an adhesive that enables it to form a bond of measurable strength immediately after adhesive and substrate are brought into contact under low pressure. Same as aggressive tack.

Tack range - The period of time in which an adhesive will remain in the tacky-dry condition after application to a substrate, under specified conditions of temperature and humidity.

Tack, dry - The property of certain adhesives, particularly nonvulcanizing rubber adhesives, to adhere on contact to themselves at a stage in the evaporation of volatile constituents, even though they seem to dry to the touch.

Tackiness - The stickiness of the surface of a sealant or adhesive.

TDS - Technical Data sheet

Tear strength - The load required to tear apart a sealant specimen.

Teeth - The resultant surface irregularities or projections formed by the breaking of filaments or strings which may form when adhesive-bonded substrates are separated.

Temperature, curing - The temperature to which an adhesive or an assembly is subjected to cure the adhesive.

Temperature, maturing - The temperature, as a function of time and bonding condition, that produces desired characteristics in bonded components.

Temperature, setting - The temperature to which an adhesive or an assembly is subjected to set the adhesive.

Tensile strength - Resistance of a material to a tensile force (a stretch). The cohesive strength of a material expressed in psi.

Themolabel - A pressure sensitive temperature measuring device that can be placed on a panel prior to pressing to measure maximum press or panel temperature.

Thermoplastic, (adjective) - Capable of being repeatedly softened by heat and hardened by cooling.

Thermoplastic, (noun) - A material that will repeatedly soften when heated and harden when cooled.

Thermoset - A material that will undergo or has undergone a chemical reaction by the action of heat, catalysts, ultraviolet light, etc., leading to a relatively infusible state.

Thermoset, state of - Pertaining to the state of a resin in which it is relatively infusible.

Thermosetting - Having the property of undergoing a chemical reaction by the action of heat, catalysts, ultraviolet light, etc., leading to a relatively infusible state.

Thinner - A volatile liquid added to an adhesive to modify the consistency or other properties.

Thixotropic - Nonsagging. A material that maintains its shape unless agitated. A Thixotropic sealant can be placed in a joint in a vertical wall and will maintain its shape without sagging during the curing process.

Time, assembly - The time interval between the spreading of the adhesive on the substrate and the application of pressure or heat, or both, to the assembly. Same as closed assembly time.

Time, curing - The period of time during which an assembly is subject to heat or pressure, or both, to cure the adhesive.

Time, drying - The period of time during which an adhesive on a substrate or an assembly is allowed to dry with or without the application of heat or pressure, or both.

Time, joint conditioning - The time interval between the removal of the joint from conditions of heat or pressure, or both, used to accomplish bonding and the attainment of approximately maximum bond strength. Sometimes called joint aging time.

Time, setting - The period of time during which an assembly is subjected to heat or pressure, or both to set the adhesive.

TLV - Threshold Limit Value set by the ACGIH.

Toxic - Poisonous or dangerous to humans by swallowing, inhalation, or contact resulting in eye or skin irritation.

Trade Secret
Confidential information that gives the owner an advantage over competitors.

Toxic Substance Control Act. Part of the EPA.

TWA - Time weighted average.

Type I water resistance - Any glue that passes ANSI Type I water resistance specification. This test is more rigorous than the Type II test. It involves specimens being immersed in boiling water for four hours, then dried in an oven at 150F, then boiled again for four hours, and cooled in water just prior to testing. Specimens must meet wood failure requirements to pass this test.

Type II water resistance - Any glue that passes the ANSI Type II water-resistance specification. This is a rigorous test that involves specimens being soaked in water for four hours, then dried in an oven at 120F. If no delamination is seen after three cycles, the glue passes.

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Ultimate elongation - Elongation at failure.

Ultraviolet light - Part of the light spectrum. Ultraviolet rays can cause chemical changes in rubbery materials.

Urethane - A family of polymers ranging from rubbery to brittle. Usually formed by the reaction of a di-isocynate with a hydroxyl.

UV - Ultraviolet Light.

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Vacuum Press - A press designed for laminating or veneering in which the panel is placed inside of a flexible bag connected to a vacuum pump.

Vapor Density - The weight of a vapor or gas compared to the weight of an equal volume of air.

Vapor Pressure - The pressure exerted by a saturated vapor above its own liquid in a closed container.

Vehicle - The liquid component of a material.

Viscosity - Measurement of material's resistance to flow.

VOC - Volatile Organic Compound.

Volatile organic compound (VOC) - Any compound of carbon, excluding carbon monoxide, carbon dioxide, carbonic acid, metallic carbides or carbonates, ammonium carbonate, and excluding any "exempt compound" which participates in atmospheric photochemical reactions. The VOC is a measured or calculated number that reflects the amount of volatile organic material that is released from a product as it dries.

Volatility - Measure of a liquid's tendency to evaporated at room conditions.

Vulcanization - A chemical reaction in which the physical properties of a rubber are changed in the direction of decreased plastic flow, less surface tackiness, and increased tensile strength by reacting it with sulfur or other suitable agents.

Vulcanize - To subject to vulcanization.

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Working life - The period of time during which an adhesive, after mixing with catalyst, solvent, or other compounding ingredients, remains suitable for use.

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X   No defined terms


Yield - The percent of usable, defect-free lumber that can be cut from a rough cutting, board, or bundle of lumber.

Yield value - The stress (either normal or shear) at which a marked increase in deformation occurs without an increase in load.

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Z (Impedance) - Variable for Electrical Impedance (The opposition a circuit offers to the flow of alternating current) expressed in ohms.

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Bird Song Adhesives, Inc., 2012