Glue Glossary

Welcome to our glossary of glue and adhesive terms. This comprehensive guide is designed to help DIY enthusiasts, crafters, professionals, and anyone interested in adhesives navigate the often complex world of glue. Understanding the terminology used in the adhesive industry is crucial for selecting the right product for your project and achieving the best results.

A · B · C · D · E · F · G · H · I · J · K · L · M · N · O · P · Q · R · S · T · U · V · W · X · Y · Z

A

A-stage: Early stage in thermosetting resin reaction, fusible and soluble.
Abhesive: Material resistant to adhesion, used as non-sticking coating.
Abrasion Resistance: Resistance to wear from mechanical action.
Accelerated Aging: Laboratory conditions simulating normal aging effects.
Accelerated Weathering: Lab conditions to simulate natural weathering effects.
Accelerator: Ingredient to speed up hardener action in adhesives.
Acceptance Test: Tests to check material conformity to standards.
Acetate: Moisture-resistant transparent film for tape backings.
Acetone: Volatile solvent for cleaning metal substrates.
ACGIH: American Conference of Governmental Industrial Hygienists.
Acrylic: Synthetic polymer used in adhesives, coatings, saturants.
Activator: Substance accelerating normal curing mechanisms.
Adhere: To bond two surfaces together.
Adherend: Body held by another through an adhesive.
Adhesion: Interfacial forces holding surfaces together.
Adhesion, Mechanical: Interlocking action holding parts together.
Adhesion, Specific: Valence forces-based adhesion.
Adhesion Build-up: Increase in adhesive’s peel strength over time.
Adhesive: Substance for surface attachment of materials.
Adhesive Failure: Loss of bond between adhesive and substrate.
Adhesive, Assembly: Used in assembling parts like boats, planes.
Adhesive, Cold-setting: Sets at temperatures below 68°F.
Adhesive, Contact: Dry to touch, adheres instantaneously upon contact.
Adhesive Dispersion: Two-phase system with one suspended in liquid.
Adhesive Joint: Location where two adherends are bonded.
Adhesive, Foamed: Lower density adhesive with gaseous cells.
Adhesive, Heat activated: Tacky or fluid upon heat application.
Adhesive, Hot melt: Bond forms on cooling from molten state.
Adhesive, Hot-setting: Requires high temperature to set.
Adhesive, Intermediate temperature setting: Sets at 31°-99°C.
Adhesive, Pressure Sensitive: Permanently tacky, adheres with slight pressure.
Adhesive, Room Temperature Setting: Sets at 20°-30°C.
Adhesive, Separate Application: Two-part adhesive for separate substrates.
Adhesive, Solvent: Volatile organic liquid vehicle-based.
Adhesive, Solvent Activated: Becomes tacky after solvent application.
Adsorption: Surface condensation and holding of gases/materials.
AFMA: American Furniture Manufacturers Association.
Aging: Progressive change in sealant or adhesive properties.
Aliphatic Resin Glue: Better grab, water, and heat resistance.
Alligatoring: Surface cracking resembling alligator hide.
Alternating Current: Electrical current with periodic direction change.
Ambient: Surrounding or usual conditions.
Ambient Temperature: Surrounding air temperature.
Amylaceous: Starch-like.
Ampere: Electric current unit.
Anaerobic: Curing in absence of oxygen.
Aniline Dye: Synthetic dye from aniline, coal tar-derived.
ANSI: American National Standards Institute.
Apparent Viscosity: Non-Newtonian fluid’s shear stress to shear rate ratio.
Arc: Visible electrical discharge through air.
Asphalt: Natural mineral pitch or bitumen.
Assembly: Group of materials or parts for bonding.
Assembly Time/Open Time: From adhesive application to pressure application.

B

B-stage: An intermediate stage in the curing process of a thermosetting resin.
Back Bedding: A technique for applying adhesive or sealant to the back of stone or similar materials.
Backer: A material used to support sealant or adhesive in a joint.
Bag Molding: A method using a flexible bag in the molding process of composite materials.
Balanced Construction: A design approach in composite materials to prevent warping.
Batch: A specific quantity of material mixed at one time.
Batten Plate: A strip used in construction for joining or reinforcing.
Bed: The foundation or the base layer for setting materials.
Bicellular Sealant Backing: A type of backing with two different cell structures.
Binder: A substance that holds or draws other materials together.
Birefringence: A property of material affecting light polarization.
Bite: The depth to which an adhesive penetrates a surface.
Blank: A pre-cut piece of material to be further processed.
Blister: A raised area on the surface of a bonded material, indicating a defect.
Blocking: The tendency of materials to stick together under pressure or temperature.

C

C-stage: The final stage in the curing process of a thermosetting resin.
Catalyst: A substance that speeds up a chemical reaction without being consumed.
Cavitation: The formation of cavities or bubbles in a liquid.
Caulking: A flexible sealant used to fill gaps and prevent leaks around openings, often used in construction and plumbing applications.
Casein glue: Derived from milk protein, forms strong, water-resistant bonds with wood, used in woodworking and furniture repair.
Cementitious: Having properties of or related to cement.
Coating: Applying a thin layer of adhesive to a surface, often used as a primer or for sealing purposes.
Cold weld adhesive: Bonds metals rapidly at room temperature without welding heat, creates strong, permanent connections.
Compatibility: The ability of an adhesive to adhere to specific materials without causing damage or weakening the bond.
Contact cement: Creates an immediate and permanent bond upon contact with both surfaces, ideal for non-porous materials like leather and plastics.
Creep: The gradual deformation of an adhesive under constant stress, can weaken bond over time.
Crosslinking: Chemical process where adhesive molecules form bonds with each other, creating a strong, three-dimensional network for increased strength and durability.
Curing: The process by which an adhesive transforms from a liquid or paste into a solid state, forming a permanent bond.
Cyanoacrylate adhesives: Commonly known as “super glue” or “CA glue”, they rapidly form strong bonds with various materials, known for their fast setting and versatility.

D

Debonding: Separation of an adhesive bond from the substrate, can occur due to various factors like improper application, incompatible materials, or stress.
Degassing: The process of removing air or gas trapped in a material.
Delamination: The separation of layers in a laminated material.
Density: The mass per unit volume of a substance.
Dielectric: A material that is a poor conductor of electricity.
Diluent: A liquid used to thin or reduce the viscosity of a substance.
Dispersion: The distribution of particles in a liquid.
Dissipation Factor: A measure of energy loss in a dielectric material.
Distortion Temperature: The temperature at which a material distorts under a specific load.
Double bonding: Chemical adhesive bonds with two specific points on an atom, offering high strength and resistance to temperature and chemicals.
Drying time: Period needed for an adhesive to lose its solvent or water and solidify, ensuring complete bond formation.
Durability: Ability of an adhesive bond to resist degradation and maintain its strength over time and under various conditions.
Ductility: Property of an adhesive to deform under stress without breaking, enhancing flexibility and resistance to cracking.

E

Elasticity: The ability of a material to return to its original shape after deformation.
Elastomer: A rubber-like material that exhibits elasticity.
Elongation: The extent to which a material can stretch before breaking.
Emulsion adhesive: Liquid adhesive where adhesive particles are suspended in another liquid, often water-based and versatile for porous materials.
Epoxy: A type of adhesive known for its strong bonding properties.
Ethyl vinyl acetate (EVA): A thermoplastic polymer used in hot melt adhesives, offering flexibility and good bonding to certain materials.
Etching: Surface treatment process to improve adhesion, often used with metals and plastics by creating microscopic roughening.
Exposure limits: Occupational safety limits for airborne concentrations of adhesive chemicals, important for worker health protection.
Extensional strain: Measure of how much a material stretches under tension, relevant for assessing adhesive deformation.
Exotherm: The release of heat during the curing process of a material.

F

Fabrication: The process of manufacturing or assembling components.
Fatigue Resistance: The ability of a material to resist weakening or failure under repeated stress.
Fibrin glue: Natural protein-based adhesive derived from blood plasma,
Filler: Inert material mixed with an adhesive to increase its volume, fill gaps, and adjust consistency for specific uses.
Film: A thin layer or coating.
Film adhesive: Thin layer of adhesive pre-applied on a carrier film, offering fast and efficient bonding for various applications.
Fixture time: Initial setting time of an adhesive, where it reaches sufficient strength to hold components in place while fully curing.
Flash point: Lowest temperature at which a liquid’s vapors ignite, relevant for safety considerations with solvent-based adhesives.
Flexible Joint: A joint designed to accommodate movement.
Flexural strength: Measure of an adhesive’s resistance to bending before breaking, crucial for flexible materials and assemblies.
Flow: The movement of adhesive or sealant under pressure.
Fluorescence: Emission of light by a substance under certain conditions.
Flux: Thin layer of material applied to surfaces before soldering or brazing, improving wetting and adhesion, sometimes also used with certain adhesives.
Fugitive glue: Adhesive designed to dissolve or release easily upon demand, typically used for temporary applications or masking purposes.

G

Gasket: A preformed shape of rubber or other material used to seal joints.
Gel: A semi-solid, jelly-like state of a material.
Gel Time: The time taken for a liquid to transform into a gel.
Gelatin adhesive: Protein-based adhesive derived from animal collagen, used in food packaging and wood repairs.
Glass transition temperature (Tg): Temperature at which a polymer changes from a glassy to a rubbery state, impacting adhesive performance and flexibility.
Graphite adhesive: Conductive adhesive containing graphite, used for bonding electronic components and dissipating heat.
Green adhesives: Adhesives formulated with environmentally friendly ingredients and low VOC emissions, promoting sustainability.
Gun applicator: Tool used to dispense adhesives in controlled amounts and patterns, common in industrial and DIY applications.

H

Hand: Refers to the feel of the adhesive, often relating to its flexibility or stiffness.
Hardener: Component in some two-part adhesives that initiates the curing process when mixed with the other component, forming a strong bond.
Haze: Slight cloudiness or loss of transparency sometimes observed in an adhesive after curing, can affect aesthetics but not necessarily bond strength.
Heat-Aging: Testing an adhesive’s performance under prolonged exposure to heat.
Heat Resistance: The ability of an adhesive to withstand high temperatures without degradation.
High Modulus: Indicates an adhesive or sealant with a high degree of stiffness.
Homopolymer: A polymer made from a single type of monomer.
Hot-glue gun: Tool used to apply hot melt adhesives, melting the adhesive stick and dispensing it for bonding various materials.
Hot melt adhesives: Thermoplastic adhesives activated by heat, offering fast bonding and strong holds for various materials.
Honeycomb bonding: Technique used to join lightweight honeycomb core materials to other structures, often employing structural adhesives for high strength and impact resistance.
Hot-press bonding: High-pressure bonding process using heat and pressure to activate and cure adhesives, commonly used in wood and composite panel manufacturing.
Humidity resistance: Ability of an adhesive bond to maintain its strength and integrity in humid environments, crucial for outdoor applications.
Hybrid adhesives: Adhesives combining different chemical or physical characteristics to achieve specific properties, like strength, flexibility, or resistance to harsh environments.
Hydrogen bonding: Intermolecular attraction between hydrogen atoms and electronegative atoms like oxygen or nitrogen, contributing to adhesion in certain materials.
Hydrolysis resistance: Chemical reaction between water and an adhesive, potentially weakening the bond over time, relevant for adhesives used in wet environments.
Hygroscopic materials: Materials that readily absorb moisture from the environment, which can affect the performance of certain adhesives.

I

Impact adhesive: Fast-acting adhesive offering high initial strength, often used for bonding metals, plastics, and wood.
Isocyanate adhesives: A class of powerful adhesives containing the isocyanate functional group, known for their strong bonding and resistance to various conditions.
Isobutyl cyanoacrylate: Specific type of cyanoacrylate adhesive (super glue) popular for its fast setting and versatile bonding capabilities.
Isolator: In adhesive bonding, a material placed between two surfaces to prevent galvanic corrosion or electrical conductivity.
Insertion polymerization: Chemical process of forming adhesive polymers by inserting monomers between existing chain molecules, offering unique strength and properties.
Interfacial bond strength: Measure of the adhesive’s force of adhesion at the interface between two bonded surfaces.
Ionic bonding: Type of adhesive bond formed through electrostatic attraction between oppositely charged ions in the adhesive and substrate.
Irreversible adhesive: Adhesive that forms a permanent bond and cannot be readily separated without damaging the materials.
Izod Impact Test: A standard test method for evaluating the impact resistance of materials.

J

Joint strength: The maximum load an adhesive can withstand before the bonded joint fails, crucial for assessing bond durability.
Jiggering: Process of aligning and holding components in place during adhesive curing to ensure proper positioning and bond formation.
Jellied adhesive: Thick, paste-like adhesive with gelatinous consistency, often used for crafts, paper applications, and temporary bonding.
Jetting adhesives: Adhesives applied using specialized dispensing equipment like nozzles or jets, offering precise and controlled application for specific tasks.
Joints: Different configurations of bonded surfaces, such as lap joints, butt joints, or tee joints, affecting the stress distribution and strength of the adhesive bond.
Joint clearance: Gap between the bonding surfaces, impacting adhesive selection and application technique, affecting bond strength and performance.
Joint Movement Capability: A measure of how much a joint can move without affecting the performance of the sealant or adhesive.
Joining pressure: Force applied during adhesive curing to ensure intimate contact between surfaces and maximize bond strength.
Jig saw puzzle adhesive: Special type of adhesive designed for repairing jigsaws, typically offering reversibility and flexibility for puzzle piece reassembly.

K

Kevlar® adhesive: High-strength adhesive reinforced with Kevlar® fibers, offering exceptional toughness and durability for demanding applications.
Keying agent: Material applied to a surface to promote mechanical interlocking and enhance adhesion, often used in bonding metals and plastics. •
Kinematic viscosity: Measure of a fluid’s resistance to flow, important for characterizing adhesive application, spreadability, and penetration into substrates.
Kinetic cure: Adhesive curing process driven by chemical reactions that progress at a specific rate depending on temperature and other factors.
Kneading: Mixing process for two-part adhesives, crucial for thorough and uniform blending of components for proper curing.
Knit Line: The line formed in a material where two flow fronts meet during molding.
Knoop hardness: Measure of a material’s resistance to indentation, relevant for assessing the surface properties of adhesives and their substrates.
Knockdown time: Initial drying or setting time of an adhesive where it loses tack but has not fully cured, allowing for adjustments to material positioning.
Krafft point: Temperature at which a surfactant or adhesive transitions from a solid to a liquid state, relevant for formulating adhesives suited for specific temperature ranges.
Krypton lasers: Specialized lasers sometimes used in laser-activated adhesive curing due to their precise wavelength and minimal thermal impact.

L

Laminar Flow: Flow of a fluid in parallel layers with minimal disruption.
Laminate: Material composed of multiple layers bonded together with an adhesive, used for various purposes like strength enhancement, waterproofing, and insulation.
Lap joint: Type of joint where two materials overlap and are bonded along their overlapping area, common in wood and metal constructions.
Lap shear strength: Measure of an adhesive’s resistance to shear stress when bonded materials overlap, crucial for load-bearing applications.
Latency time: Period between applying an adhesive and its activation, relevant for latent hardening adhesives and influencing process planning.
Latent hardening adhesive: Adhesive that remains inactive until exposed to a specific activation factor, like heat or light, offering precise control over bonding initiation.
Leaching: Diffusion of adhesive components into surrounding materials, potentially weakening the bond or causing unwanted contamination.
Life: The period during which a product can be used effectively.
Load: The weight or force that a bonded joint must withstand.
Long open time: Duration during which an adhesive remains workable and allows for adjustments before setting, advantageous for large or complex assemblies.
Loss tangent: Measure of a material’s electrical energy dissipation, important for characterizing dielectric properties of some adhesives used in electronics.
Low-molecular-weight (LMW) adhesive: Adhesive composed of small molecules, typically offering good penetration and flexibility but potentially lower strength compared to high-molecular-weight (HMW) adhesives.
Lubricant: Substance added to an adhesive to reduce friction and improve flow during application, beneficial for certain materials and processes.

M

Mandrel: A tool around which material is shaped or formed.
Masking adhesive: Temporary adhesive used to protect specific areas during painting, coating, or other processes.
Matrix: A material in which something else is embedded or enclosed.
Mechanical adhesion: Bonding achieved through interlocking of surface features, relevant for rough or fibrous materials.
Melamine adhesive: Urea-formaldehyde resin glue offering water resistance and good bonding to wood and other materials.
Melting point: Temperature at which a solid adhesive transitions to a liquid state, relevant for hot melt applications.
Mesh size: Measurement of the openings in a screen or mesh used for applying adhesives, affecting thickness and texture.
Microencapsulation: Technique where microscopic capsules containing adhesive are embedded in a material, releasing the adhesive upon triggering.
Mixed mode fracture: Type of fracture involving a combination of opening and shearing forces, relevant for assessing adhesive bond strength.
Mixing ratio: Specific proportions of two or more components required for an adhesive to cure properly and achieve optimal performance.
Modulus of elasticity: Measure of an adhesive’s stiffness or resistance to deformation under stress, crucial for maintaining bond strength.
Moisture cure: Adhesives that harden through reaction with moisture in the air, often used for construction and woodworking applications.
Mold release: Agent applied to molds to prevent adhesion of cured materials, often used in casting and manufacturing processes.
Monomer: Single molecule that reacts with others to form a polymer, relevant in understanding adhesive chemistry.
MS polymer: Modified silane adhesive offering high strength, flexibility, and weather resistance, suitable for various materials.
Mucilage: Natural adhesive substance derived from plants, used in traditional bookbinding and paper crafts.

N

Nanoparticles: Tiny particles (1-100 nm) used in some advanced adhesives to improve strength, conductivity, or self-healing properties.
Natural rubber adhesive: Adhesive derived from the sap of rubber trees, offering good flexibility and tack for various materials.
Neutral Cure: A type of silicone sealant that cures without acidic by-products.
Non-destructive testing: Methods to evaluate adhesive bond strength without damaging the materials, like ultrasonic testing or vibration analysis.
Non-Sag: A property where the adhesive or sealant doesn’t flow under its own weight.
Non-Skinning: An adhesive or sealant that remains tacky and doesn’t form a skin.
Non-Staining: Refers to adhesives or sealants that don’t leave stains on substrates.
Non-Volatile Content: The percentage of a substance in an adhesive that doesn’t evaporate.
Nylon adhesives: Strong and versatile adhesives based on nylon polymers, often used for high-performance applications like metal bonding.

O

Open time: The amount of time an adhesive remains workable and bondable after application before it begins to cure. Longer open time allows for adjustments and positioning of materials.
Optical adhesives: Adhesives specifically formulated for applications requiring high optical clarity and minimal distortion, used in lenses, displays, and optical instruments.
Organic: Refers to compounds containing carbon, typically used in the context of solvents or adhesives.
Orientation: Arrangement of molecules or fibers within an adhesive, impacting its properties like strength and flexibility.
Oligomer: Short polymer chain, a precursor molecule that can undergo further polymerization to form a stronger adhesive.
One-component adhesive: Adhesive requiring only one component for curing, offering convenience and ease of use compared to two-component systems.
Open assembly time: Time frame during which parts can be assembled after applying an adhesive before significant curing begins, ensuring proper alignment and positioning.
Outgassing: Release of volatile chemicals from an adhesive after curing, a concern in certain applications like aerospace where it can affect sensitive equipment.
Overcuring: Exposing an adhesive to excessive heat or curing time, potentially leading to brittleness or reduced performance.
Overlap area: The surface area shared by bonded materials, crucial for determining joint strength and stress distribution.
Oxidation: Chemical reaction between an adhesive and oxygen, sometimes influencing its longevity and performance.

P

Peel strength: Measure of force required to separate bonded surfaces, crucial for assessing adhesive’s performance under stress.
Peel test: Standard test method to measure the peel strength of an adhesive bond, providing valuable data for material selection and quality control.
Pigment: A substance that imparts color to another material.
Phenolic adhesives: Strong, heat-resistant adhesives used in high-temperature applications like aircraft and automotive parts.
Plastic deformation: Permanent change in an adhesive’s shape under stress, impacting bond strength and durability.
Plasticizer: Additive that increases flexibility and reduces brittleness of an adhesive, often used in PVC-based formulations.
Polymer: A large molecule made from repeating structural units.
Pot Life: The time during which an adhesive remains usable after mixing.
Prepreg: Reinforcing fibers pre-impregnated with a resin matrix.
Primer: Surface pre-treatment applied before adhesive application to improve adhesion and bond strength.
PSA (Pressure Sensitive Adhesive): An adhesive which forms a bond when pressure is applied.
Polyamide adhesives: Versatile adhesives offering good adhesion to various materials, like metals, plastics, and wood.
Polyurethane adhesives: Strong, durable adhesives with excellent resistance to moisture, chemicals, and aging.
Polyvinyl acetate (PVA): Common water-based adhesive widely used for wood and craft applications, known for its affordability and ease of use.
Polyvinyl chloride (PVC): Common thermoplastic material sometimes used in adhesive formulations, offering good mechanical properties and chemical resistance.
Pot life: Working time of an adhesive, the period during which it remains workable after mixing or application.
Pressure-sensitive adhesives (PSAs): Adhesives that form bonds upon pressure without requiring additional activation like heat or curing.
Pretreatment: Any process applied to surfaces before adhesive application to improve adhesion, like cleaning, roughening, or priming.

R

Ragging: A decorative technique using a rag to create patterns.
Reactive adhesives: Adhesives that undergo a chemical reaction during curing, forming strong covalent bonds with the adhered surfaces.
Redistribution: Movement of adhesive within a joint after application, potentially affecting bond strength and uniformity.
Release agent: Material applied to surfaces to prevent adhesives from sticking, useful for temporary bonding applications or mold release.
Repositionable Adhesive: An adhesive allowing objects to be moved after initial application.
Residual stress: Internal stress present in an adhesive bond due to curing shrinkage or expansion, impacting long-term durability.
Resins: Organic materials often used as the main component in adhesives, offering strong bonding and diverse properties depending on the specific type.
Rigid Adhesive: An adhesive that doesn’t flex after curing.
Rheology: Study of the flow and deformation of materials, crucial for understanding the behavior of adhesives under stress and during application.
Room Temperature Cure: Adhesive curing at ambient temperature.
Rheometer: Instrument used to measure the rheological properties of materials, including adhesives, providing key insights into their flow and deformation behavior.
Room temperature cure: Adhesive that cures and reaches its final strength at room temperature, eliminating the need for additional heating or pressure.
Rotational viscosity: Measure of a material’s resistance to flow under shear stress, relevant for determining the application properties of adhesives.
Rubber cement: Fast-drying adhesive with a rubbery consistency, typically used for temporary bonding like paper or fabric.
Rubber-to-metal bonding: Specific type of adhesive application for joining rubber components to metal, requiring high flexibility and adhesion strength.
Rupture strength: Maximum stress an adhesive joint can withstand before breaking, critical for assessing bond strength and durability.

S

Sag: Tendency of a material to flow downward after application.
Sandwich Construction: A structure made of a lightweight core and two bonded face sheets.
Scarf Joint: A joint made by beveling edges to be joined.
Sealant: A material used to seal gaps or joints.
Set: The process of adhesive becoming firm or hard.
Shear strength: Measure of an adhesive’s resistance to sliding forces, crucial for load-bearing applications and structural joints.
Shelf life: Period an adhesive remains usable and maintains its performance after manufacture, important for storage and inventory management.
Shrinkage: Decrease in volume or dimension of an adhesive during curing, can cause gaps or cracks if not accounted for.
Skin: A layer that forms on the top of certain adhesives or sealants.
Slip adhesion: Type of adhesion where surfaces can slide along each other slightly under stress, beneficial for certain dynamic applications.
Solids content: Percentage of non-volatile solids in an adhesive, often indicating its thickness and coverage capacity.
Solvent: Liquid that dissolves another substance, used in many adhesives to control viscosity and application properties.
Stress: Force applied to a material per unit area, a key factor in understanding and predicting adhesive behavior.
Substrate: Material to which an adhesive is applied to form a bond, can be diverse like wood, metal, plastic, or fabric.
Surface activation: Treatment process to improve the bonding capability of a surface, often used with low-energy materials.
Synergistic effect: Positive interaction between different adhesive components, resulting in enhanced performance beyond individual contributions.

T

Tack: The initial stickiness of an adhesive before full curing, crucial for holding components in place during application.
Tack coat: A thin layer of adhesive applied to a surface before bonding to improve initial sticking and promote adhesion.
Tack range: Time during which an adhesive stays tacky-dry.
Tackiness: Stickiness of a sealant or adhesive’s surface.
Tear strength: Measure of an adhesive’s resistance to tearing or ripping, important for applications exposed to stress or strain.
Teeth: Surface irregularities from breaking of adhesive filaments.
Telegraphing: Visible transmission of inner layer imperfections to a surface.
Temperature, Curing: Heat applied to cure an adhesive.
Temperature, Maturing: Heat for desired characteristics in bonded components.
Temperature resistance: Ability of an adhesive to maintain its performance and bond strength over a range of temperatures.
Temperature, Setting: Heat applied to set an adhesive.
Tensile Strength: Material’s resistance to tensile force.
Thermoplastic: Material softening with heat and hardening with cooling.
Thermoset: Material becoming infusible through chemical reaction.
Thermoset adhesives: Adhesives that undergo chemical reactions during curing, forming permanent, cross-linked networks that resist solvents and high temperatures.
Thinner: Liquid added to modify adhesive properties.
Thixotropy: Property of a material to become less viscous under stress or shear, making it easy to apply but hold its shape at rest.
Time, Assembly: Interval between adhesive application and pressure/heat.
Time, Curing: Duration for adhesive curing.
Time, Drying: Duration for adhesive drying.
Time, Joint Conditioning: Interval for joint to attain maximum bond strength.
Time, Setting: Period for setting the adhesive.
TLV: Threshold Limit Value set by ACGIH.
Toxicity: Level of harmfulness of an adhesive’s chemical components, relevant for safety considerations and proper handling.
Transfer adhesive: Adhesive designed to bond to one surface and then, upon pressure, transfer to another surface, often used for labels and tapes.
Transparency: Degree to which an adhesive allows light to pass through, important for aesthetic considerations and certain applications.
TSCA: The Toxic Substance Control Act is a United States federal environmental law that grants the Environmental Protection Agency (EPA) the authority to regulate the manufacture, import, processing, distribution, and disposal of chemical substances, including those used in glues and adhesives.
TWA (Time-Weighted Average): refers to the average concentration of airborne adhesive chemicals that a worker is exposed to over a specific period of time, typically during an 8-hour workday.
Two-part adhesive: Adhesive composed of two separate components that need to be mixed before use, offering high strength and versatility.
Type I water resistance: ANSI test for glue water resistance.
Type II water resistance: Another ANSI water-resistance test for glue.
Tyre adhesion: Specific aspect of adhesion related to bonding materials used in tire construction, crucial for safety and performance.

U

UV: Refers to Ultraviolet Light.
Ultimate Elongation: The maximum elongation a material experiences before failing.
Ultraviolet (UV) curing: Method where adhesives solidify when exposed to ultraviolet light, offering fast curing times and high bond strength.
Ultraviolet Light: A part of the light spectrum known to cause chemical changes in certain materials.
Ultimate tensile strength: Maximum force an adhesive bond can withstand before breaking, a crucial measure of its long-term performance.
Ultraviolet (UV) resistant: Ability of an adhesive to maintain its performance and properties when exposed to sunlight or artificial UV radiation.
Unprimed adhesion: Ability of an adhesive to bond directly to a surface without pretreatment, simplifying application and reducing process steps.
Unsupported film adhesive: Pre-applied adhesive film without a carrier film, designed for direct application to specific surfaces.
Urethane: A diverse family of polymers, ranging in consistency, typically formed by reacting a di-isocyanate with a hydroxyl.

V

V-joint: A glue joint with uneven thickness due to machining or pressure application.
Vacuum Bagging: Technique for applying pressure during adhesive curing using a sealed bag and vacuum pump, ensuring good contact and minimizing air bubbles.
Vacuum Press: A press used for laminating or veneering with a vacuum bag.
Vapor Density: Weight comparison of a vapor or gas to an equal volume of air.
Vapor Pressure: Pressure exerted by a vapor above its liquid in a closed container.
Vehicle: The liquid component in a material.
Veneer: A thin piece of wood, usually less than 1/8″ thick.
Viscosity: Resistance of a fluid to flow, affecting the ease of application and spreadability of an adhesive.
VOC: Abbreviation for Volatile Organic Compound.
Void filler: Additive mixed with an adhesive to bridge gaps and uneven surfaces, enhancing bond strength and preventing voids.
Volatility: A liquid’s tendency to evaporate at room conditions.
Volt: Unit measuring electromotive force.
Volatile Organic Compounds (VOCs): Organic chemicals that evaporate at room temperature, some adhesives emit VOCs which can affect air quality and require ventilation.
Vulcanization: Process of cross-linking rubber or certain polymers using heat and pressure, improving their strength and elasticity. Some adhesives may involve vulcanization during curing.

W

Warp: Deviation from a true or original surface.
Waterborne adhesives: These use water as the primary solvent and are generally considered low in volatile organic compounds (VOCs). This makes them a more environmentally friendly option than solvent-based adhesives.
Watt: Unit of electric power, calculated as volts times amperes.
Wax-based adhesives: These adhesives use wax as the main binding agent and are often used for temporary or non-structural applications. They are typically easy to apply and remove.
Webbing: Formation of filaments when adhesive surfaces are separated.
Weld line: This is the visible line where two materials have been joined with an adhesive. The strength and appearance of the weld line can vary depending on the adhesive and application.
Wettability: This refers to the ability of a liquid to spread and adhere to a solid surface. Good wettability is essential for strong bonds with adhesives.
Wet bonding: This refers to the process of applying adhesive to surfaces that are already wet. This can be done with some types of adhesives, but it is important to follow the manufacturer’s instructions carefully.
White glue: Also known as polyvinyl acetate (PVA) glue, white glue is a common water-based adhesive widely used for household, woodworking, and various artistic applications. It’s characterized by its white color, smooth consistency, and relatively short drying time.
Wick: In adhesive applications, a wick is a porous material that draws or transfers adhesive into a joint or onto a surface. They can be used to control the flow of adhesive and ensure proper filling of gaps.
Wicking test: This is a test used to measure the wettability of a surface. A drop of liquid is placed on the surface, and the time it takes for the liquid to be absorbed is measured.
Wood Failure: Rupturing of wood fibers in bonded specimens during strength tests.
Wood glue is a general term for adhesives specifically designed for bonding wood. Various types include VA, polyurethane, and epoxy.
Wood Welder: A handheld radio frequency device for assembly gluing.
Wood, Built-up Laminated: Layers of lumber joined with the grain parallel.
Working Life: Time an adhesive remains usable after mixing with other ingredients.

X

X (Reactance): Represents opposition to alternating current in electrical terms.
Xenon Oxide: A gas used in UV-curable adhesives.
Xylitol: A sugar alcohol serving as a plasticizer in adhesives.
X-Ray Diffraction: A technique for analyzing adhesive materials’ crystal structure.
Xenobonding: Adhesive bonding between materials with different surface energies.
Xyloglucan: A component in bio-based adhesives, found in plant cell walls.
X-Ray Fluorescence (XRF): Analyzes elemental composition of adhesives.
X-Ray Photoelectron Spectroscopy (XPS): Used for surface chemistry analysis of adhesives.
Xylanase: An enzyme for modifying wood surfaces to enhance adhesion.
Xerogel: A type of gel in adhesives, formed by drying a colloidal suspension.
Xanthane Gum: A polysaccharide used as a thickener in adhesives.
Xenotransplantation: Relevant in biocompatible adhesive research for medical applications.

Y

Yam starch: Biopolymer sometimes used as a thickener or binder in certain adhesives.
Yaw angle: Deviation of a bonded joint from its intended alignment, crucial for accuracy.
Yellow dextrin: Carbohydrate adhesive derived from corn starch, useful for paper applications.
Yellow light guide (YLG): Component in certain UV curing systems for adhesives.
Yellowing index: Measure of yellowing or discoloration over time, important for aesthetic aspects of adhesives.
Yield: Percentage of defect-free lumber from a rough cut.
Yield point: Stress at which a material begins to deform plastically, relevant for adhesive strength.
Yield Value: Stress point where deformation increases without additional load.
Young’s modulus: Measure of a material’s stiffness, affecting adhesive flexibility.
Yttrium-stabilized zirconia (YSZ): Material used in some high-temperature resistant adhesives.

Z

Z (Impedance): Electrical impedance, the opposition to alternating current flow.
Zein: Corn protein sometimes used as a bio-based adhesive
Zinc stearate: Lubricant used in some hot melt adhesives
Zwitterionic adhesives: Adhesives containing both positive and negative charges, offering unique binding properties
Zymogen activation: Enzyme activation process relevant to some enzymatic adhesives
Zeta potential: Surface charge of colloidal particles, crucial for understanding adhesion in dispersions
Ziegler-Natta catalysts: Catalysts used in the production of some synthetic polymers for adhesives
Zirconium oxide: Abrasive sometimes used in adhesive preparation or surface treatment
Zwitterionomers: Polymers containing zwitterionic groups, with potential applications in self-healing adhesives
Zymogenesis: Enzyme production process, important for understanding enzymatic adhesives
Zwitterionic copolymers: Polymers containing both hydrophilic and hydrophobic zwitterionic groups, offering versatile adhesion properties