Adhesives Education

Whether you’re looking to learn more about the adhesives industry, individual adhesive products, or APPLIED Adhesives, look no further than this curated list of educational materials. Your APPLIED team is always ready to help with additional questions – contact an expert.

Watch

How to Check for Frozen Product

Case Sealing Application

Hot Melt Stringing - Slow Motion

Emmeci machine - Set up box application

Adhesive Spray Test

Pacific BREAKAWAY Palletizing Adhesive

Glue 101

Most people use the words interchangeably and it’s not necessarily incorrect—both make things stick together. The difference is in the chemistry of the material.

No. There are many different formulations to meet specific usage requirements. An APPLIED expert can help you determine the best adhesive for your needscontact us.

The ability of solid materials to resist damage by chemical reactivity or solvent action.

This type of adhesive is designed to have no char, excellent machining, good combination of heat and cold resistance, excellent bond strength on difficult substrates, and low cost of ownership.

With too much oxygen, heat, and time, adhesive can get char buildup.

Cleaning of hot melt products is best accomplished:

  • in non-melt tank areas at room temperature
  • using citrus-based solvents which allow the hot melt to soften
  • manually scrapping with a blade for product removal

When switching from one hot melt to another, a thorough cleaning, using appropriate purge material is strongly suggested prior to start up.

  • Completely drain the current conventional hot melt adhesive for the adhesive melt pot including all dispensing lines.
  • Remove all filters and screens
  • Use a plant approved solvent –such as high boiling citrus-based cleaning solvents with cleaning chisels and scrappers
    • thoroughly clean the inside of the glue pot (via wiping with dampened rags), the outside of the glue pot and melt unit, all screens and filter as well as the dispensing head. Be sure that all of the cleaned components are completely dry (no citrus residue) before putting back into the melt unit.

For best results when cleaning up water-based adhesive:

  • Clean product in its wet form immediately with warm water and/or with warm water and soap.
  • For dried adhesive product use warm water and manual scrapping.
  • For difficult to remove dried adhesive product, use polar solvents (such as alcohols or ketones) or environmentally-friendly solvents (such as those based on citric materials) for cleaning.
  • When using environmentally-friendly solvents, a final wipe with a polar solvent is suggested

 Follow these guidelines to prevent glue char:

  • Use a high quality, stable hot melt
  • Use the recommended application temperature (not too hot) for the hot-melt chemistry
  • Avoid having glue sitting (and cooking) in the pot too long before use
  • Ensure you have enough glue in the pot
  • Use hoses that are well insulated

The right equipment can make a big difference when it comes to glue char. Contact us to upgrade to a Nordson hot-melt delivery system.

Follow these guidelines to prevent boxes from popping open:

  • Use adhesive with fast set speed
  • Use the proper amount of adhesive (not too much, not too little)
  • Position the adhesive correctly on the box
  • Ensure you have the right adhesive for the application
  • Use good compression
  • Apply adhesive at the proper temperature

An APPLIED technician can conduct a process audit to determine any issues—contact us.

Follow these guidelines to prevent flagging labels:

  • Use the correct adhesive with the right tack
  • Use the proper amount of adhesive (not too much, not too little)
  • Ensure the transfer mechanism is properly contacting labels
  • Apply adhesive consistently and check for worn pallet
  • Set up brushes and compression properly
  • Check label for proper humidity content
  • Check label for grain direction.

An APPLIED technician can conduct a process audit to determine any issuescontact us.

An APPLIED technician can conduct an adhesive line audit to determine any issuescontact us. Equipment can be part of the solution, often. Installing a Nordson Fulfill Adhesive Tracking System (ATS) Retrofit with an Eco Bead controller allows you to dial into adhesive savings with different patterns and bead stitching.

  • Operators should regularly add adhesive to Hot Melt Tank
    • This avoids Thermal Shock of the system and maintains consistent pump pressure
    • This avoids air space in the tank and reduces char
  • Keep Melter Lid Closed
    • Avoid oxidation and contamination
  • Use Global Temperature Set Points When Possible
  • Use Uniform Nozzle Size
  • Refer to Posted Placards for Baseline Temperatures & Pressure
  • Utilize Schedulers for Set-Back or Idle Machine Temperatures
  • Identify Proper Proactive Maintenance Schedule and Keep Spare Parts On-Hand
  • Utilize SDS and TDS as well as Equipment Manuals for proper operation
  • Utilize ‘First-In, First-Out’ Inventory Practices
  • Keep Hot-Melt Boxes Closed, in a Cool Dry Location

Extremely cold winter weather can present challenges for shipping adhesive materials.

By following these steps, you can make sure your adhesives are shipped in perfect condition.

Make sure you follow these steps before signing off on water-based adhesive reception.

STEP 1

  • Check the weather from time of order to time of shipment
  • If it has fallen below 32° F or 0° C, there may be frozen product.

STEP 2

Inspect your adhesive product for any signs of freezing, watch our video on How to Check for Frozen Product.

Frozen or partially frozen water-based product may have:

  • A solid layer on the bottom of the drum
  • Coagulation on the surface of the adhesive resembling cottage cheese
  • Hard frozen product
  • Ice crystals on the surface

STEP 3

  • If you find any of these conditions, report the problem to your supplier prior to signing off on the bill of lading.
  • Disposal of frozen materials is very costly, and it becomes your responsibility once you sign for the shipment and relieves the shipping company from further action.

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 impregnates; 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.

Brookfield Viscosity

Standard measure of viscosity in the hot-melt industry, expressed in centipoise at a specific temperature.

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 impregnates; 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.

Char

Hard, black particles often found in hot-melt application equipment, resulting from adhesive or foreign particle degradation.

Chemical Resistance

Ability of solid materials to resist damage by chemical reactivity or solvent action.

Cohesive Strength

Internal strength of an adhesive.

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, and 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°F.

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, and 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 a substrate by evaporation of the solvent components of the adhesive composition; drying can also be accomplished by absorption of the solvent components on the substrate.

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)

Hot-Melt Adhesive

Thermoplastic compound which becomes sufficiently fluid when heated to be pourable or spreadable, and cools to form a coating or adhesive bond.

Hot Tack

Cohesive strength of a molten hot-melt adhesive which is desired during sealing to hold mated pieces together while a bond is being formed.

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 embedding 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.

Methacrylate

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, and etc. over a wide range of temperatures based on butadiene acry-lonitrile.

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.

Open Time

Period after an adhesive is applied during which it remains sufficiently molten to affect a bond.

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 styrenes, condensation polymers and epoxies, phenolics, and silicones.

Polymerization

The process involves 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 calendaring processes to produce various plastic products including 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 process ability 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, and 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

Polyvinyl Chloride; 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.

Ring & Ball Softening Point

Temperature at which a small steel ball will fall through a disc of hot-melt adhesive supported in a ring.

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 trees (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.

Set-Time

Time required to solidify or set the hot-melt adhesive once the mating surfaces are compressed.

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.

Skinning

Formation of a viscous and often discolored layer on the surface of hot-melt adhesive in a melt tank.

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 a substrate, 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.

UHS

Ultra-High Solids. Emulsion products characterized by a moderate viscosity and a solids level in excess of 72%.

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.

Thixotropy

The property of certain adhesive compositions to thin upon isothermal agitation and to thicken upon subsequent resting (i.e. cessation of the agitation).

Webbing

The formation of filments or threads when adhesive transfer surfaces are separated.

Wetting

The coating of a substrate surface with an adhesive.

Wicking

The flow of an adhesive into a tightly restricted opening.

Viscosity

The resistance of a fluid to flow; the ratio of shear stress between laminates of moving fluid and the rate of shear between these laminates.

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