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Adhesive tape converting glossary
Sharing our knowledge with the medical device market
The need to know’s and the A’s to Z’s.
A
Accelerated Ageing
A simulation used to predict the effects of natural ageing. Procedures used are elevated temperatures, high-intensity light, high humidity or all of the above cycled.
Acrylic Adhesive
A pressure-sensitive adhesive formed by the polymerization of acrylic ester monomers. These adhesives exhibit high temperature resistance, excellent U.V. resistance and good ageing characteristics.
Activate
To change an adhesive film from a dry stage into a useful tacky state.
Adhere
To bond; to cause two surfaces to be held together by adhesion.
Adhesion
The molecular force of attraction or bond between any adhesive and the surface it is in contact with. The strength of the attraction or bond is determined by the surface energy of the material and the type of adhesive involved.
Adhesion (Peel)
Force required to remove a pressure sensitive tape from a well-defined test panel under standard conditions.
Adhesion Build-Up
An increase in the peel adhesion value of a pressure-sensitive adhesive tape, after it has been allowed to dwell on the applied surface. Result of the adhesive “wetting out” on the substrate.
Adhesive
The pressure-sensitive adhesive layer applied to a tape which will usefully hold two surfaces together by intimate contact.
Adhesive Transfer
The transfer of adhesive from its normal position to the surface it was just unwound from. Transfer tapes demonstrate this phenomenon because of the differential release on the release liner.
Ageing
The changes undergone by a material in function time.
Anilox System
The inking system commonly employed in flexographic printing, consisting of an elastomer covered fountain roller running in the ink pan. Adjustable against an engraved anilox roll, the two as a unit are adjusted to the printing plate roll, ink is flooded into the engraved cells of the anilox roll, excess doctored off by the doctor blade and that which remains beneath the surface of the anilox roll is transferred to the printing plate.
B
Back Split
Slits in the release liner to facilitate easy removal by hand.
Backing
An inexact term used in the pressure-sensitive adhesive industry. When referring to double-coated tapes and single–coated products, it is the release liner. When referring to self-wound tapes, it is the material to which the adhesive is bonded.
Bleeding
The undesirable penetration of the adhesive onto the surface to which the tape is applied.
Bond
The adhesion of pressure-sensitive adhesive tape to the surface to which it has been applied.
Bond Strength
The amount of force required to separate the joined surfaces.
Butt Splice
A splice made by joining tape end to end without overlapping. The splice is assembled by a thin single coated tape centred on both sides.
Butt-Cut
Butt-cutting refers to a conversion process where a die creates individual pieces by cutting through the laminated material and adhesive. In Butt-cutting there is no waste area left between the adjoining pieces.
C
Calendered
An adjective describing a finish achieved by passing material through rollers to produce a smooth surface.
Calendering
Continuous sheet manufacture by passing material between heated, polished rollers under high pressure to produce a smooth finish.
Caliper
A measurement of thickness expressed in thousands of an inch (English units) or millimetres (Metric units).
Carrier
When referring to double-coated tapes, it is the thin medium which the adhesive is anchored to on both sides.
Chad
Scraps or tiny pieces of material removed from web during die cutting and/or sprocketing
Coated - Double
Tape construction on which the carrier has on both sides an adhesive coating.
Coated – Single
Tape construction on which the carrier has only on one side an adhesive coating.
Coater
A machine composed of an unwind stand, coating devices, rollers, ovens and wind-up stand used to apply adhesive to backing and or carriers to produce a pressure-sensitive tape.
Coating
Technique of applying adhesive to a carrier.
Coating Weight
The weight of an adhesive per unit area. Also known as Adhesive Mass.
Cohesive Strength
The internal strength of adhesive and its ability to resist splitting caused by external forces. It is measured by its resistance to forces parallel to the surface. Good cohesion is necessary for clean removal.
Cold Flow
The extremely slow flow or minute movement of a pressure-sensitive adhesive under stress over a period of time on a surface. It accounts for increased adhesion and relates to oozing adhesive from the edges of a roll.
Conformability
The ability of a tape to fit snuggly or to make total contact with the contours of a surface without creasing or folding.
Cross Direction
The direction at right angles to the machine direction of a web to which it runs through the machine.
Cure
To change the properties of an adhesive by chemical reaction or heat alone, or in combination with or without pressure.
D
Delamination
The undesirable separation or buckling of the release liner from an adhesive layer usually parallel to the direction of the web. Most often found during high humidity conditions causing the paper to ‘grow’.
Densitometer
A photo-electric instrument that measures the optical density of images or colours. A reflection densitometer measures the amount of incident light reflecting from the surface of a substrates such as ink on paper or film. A transmission densitometer measures the amount of light transmitted through film from a measured light source.
Deterioration
Undesirable change in properties of an adhesive caused by ageing, weathering, etc.
Die Cut
The thin line of severance between a pressure-sensitive tape or label and its matrix made by the cutting edge of a die.
Dimensional Stability
The property of a material which relates to the constancy of its dimensions.
Direction – Cross
The direction at right-angles to the machine direction of a web through a machine.
Direction – Machine
The direction parallel to a forward movement of a web.
Dishing
A sideways sliding of the tape layers, one over the other in such a manner that the roll looks like a funnel or telescope.
Doctor Blade
An adjustable knife-like bar which controls the amount of ink, coating, adhesive, etc from the anilox or other roller.
Double-Coated
A pressure-sensitive tape consisting of a carrier with similar or dissimilar adhesive applied to both surfaces.
Double-Sided
A pressure-sensitive tape consisting of a carrier with similar or dissimilar adhesive applied to both surfaces.
Dry Edge/Finger-Lift
Double coated tape with adhesive edge removed
E
Easy Release
The liner removes readily from the adhesive/carrier.
Edge Curl
The peeling back or lifting of the outer edge of a tape which has been applied to a curved surface.
Elastomer
Generally a rubber-like substance which is easily deformed by a force but returns to its original shape. Elastomers are the basis of most pressure-sensitive adhesives.
Elongation
The distance a tape will stretch lengthwise before breaking. Expressed as a percentage of original length. Elongation is not necessarily an indication of conformability.
Emboss
To create a design on a surface caused by letter, figures, patterns, etc, to be raised by dies.
Extrude
To expel or force through a measured orifice; to apply a molten thermoplastic adhesive onto a web.
F
Face Side
The unlinered side of a double-coated tape.
Feel
The degree of stickiness of the adhesive determined by touching with one’s finger. This is often a misleading test to determine adhesion.
Fibre Filled
Fibre Filled refers to an adhesive that has had fibre added to it. These fibres help in conversion of the products, by preventing adhesive flow. Fibre filling does allow for as much elongation as a regular transfer tape. Fibre filling does not provide as much stability in conversion as a Carriered product.
Films
Uniform, homogenous, non-fibrous synthetic webs.
Fisheyes
Relatively small deformation (pock-marks) in the adhesive caused by the entrapment of air between the adhesive side and the back side of the previous layer on the roll. This is not an indication of a quality defect and is generally found in new or fresh tape. Diminishes during storage.
Flexographic Printing
Flexo printing is a direct flat or rotary printing process with elastic, raised printing formes or plates, which can be attached to plate or printing cylinders of different circumferences. Ink is applied with a rubber roller and/or an anilox roller with a doctor blade and relatively high viscosity water, solvent based or UV curable printing inks. The system was initially developed in the beginning of the 19th century to print wallpaper. By the end of the 19th century it was used for printing packaging paper and board. The name was chosen in 1952 and is derived from the earlier name aniline printing, relating to the early types of inks used.
Flow Out
The ability of an adhesive to level after application. See Wetting.
Foam
A soft, cushioning material formed by creating bubbles in base material.
G
Ghosting
A haze-like deposit of an adhesive left by a tape after its removal.
Glassine
A super-calendered smooth dense transparent or semi-transparent paper.
Grain
The machine direction of paper as opposed to the cross direction. Also, a measurement of pressure-sensitive adhesive on a given area.
Gravure Coater
Applies a specific amount of coating controlled by an etched roll to a surface.
h
Heat Ageing
A controlled environment to provide an indication of any deterioration of an end use or finished product.
Heat Resistance
The ability of a tape to withstand high temperature exposure after application. Clean removal after exposure may or may not be important depending on the intended function of the tape and the type of adhesive.
High Release
The liner is more difficult to remove from the adhesive/carrier producing high release adhesion.
Hold
The molecular force of attraction or bond between any adhesive and the surface it is in contact with. The strength of the attraction or bond is determined by the surface energy of the material and the type of adhesive involved.
Holding Power
The ability of a tape to resist slippage under shear stress. Usually measured by applying a standard area of tape to a vertical test panel and suspending a standard weight on the free end of the tape.
Hot Melt
A pressure-sensitive adhesive applied to the liner or backing in a hot molten form which cools to form a conventional pressure-sensitive adhesive.
Hydrocolloids
Special types of pressure sensitive adhesives particularly used in the medical field due to their unique dual attributes of absorbency and adhesiveness.
I
Individual Pieces
Die cut pieces cut right through tape and liner or using exact width of tape required and guillotining at a set length to produce finished parts.
Inhibitor
A substance which slows down chemical reaction. Inhibitors are sometimes used in adhesives to prolong their life or storage.
Internal Strength
Split strength.
K
Kiss-Cut
Kiss-Cutting refers to a die cutting method where the die cuts through the laminated material and adhesive and stops before rupturing the liner. In this process the waste matrix is often removed.
Knife Coating
A method of adhesive coating. It essentially consists of a rigid adjustable blade mounted above a roll. The adhesive is pumped behind the blade so it is pulled under the blade.
L
Lacquer
A solution that is applied to release liners forming a thin protective film with special properties after the solvents have evaporated.
Lamination
The process of bonding together of two or more materials.
Lap Splice
A splice made by overlapping the ends.
Lifting
Refers to the condition when a tape, on its own accord, comes away from the surface to which it was applied.
Liner
A backing coated on one or both sides that protects the adhesive until use. The liner is removed and discarded before application. Most frequently found on double coated tapes and labels.
Liner – Oversize
Applying a wider liner than the tape. Assists in easy removal of the tape from the liner.
Liner Side
In roll form it refers to that side of the roll protected by the release liner.
Log Roll
A roll of tape, normally 1m in width, wound in a predetermined length of usually 250m.
Low Release
The liner removes readily from the adhesive/carrier.
M
Machine Direction
The direction of tape parallel to its forward motion on a converting machine.
Mass
Sometimes used as another name for the adhesive.
Mass Weight
The weight of an adhesive per unit area. Also known as Adhesive Mass.
Master Roll
A roll of tape, normally 1m in width, wound in a predetermined length of usually 250m.
Matrix
The total construction of a pressure-sensitive adhesive system surrounding a die-cut form which has been removed.
Memory
The property of a material that attempts to return to its original dimension after being distorted.
Migration
The slow movement of one or more components from a substrate that chemically attacks the adhesive or vice versa. Some plastic films and foams contain plasticizers which migrate into the adhesive and soften it.
Mils
Used in describing adhesive coat weights, thickness. The term means thousandths of an inch.
Monomer
The basic building block from which a polymer chain is made. Many monomer molecules are chemically joined to make up the polymer.
N
Non-Blocking
Pertaining to an adhesive film that will not adhere to itself and/or other surfaces under normal stacked conditions.
Non-Oriented Film
Film which has not been subject to stress to align the polymer chains and improve properties.
Non-Woven Materials
Random interlocked paper tissues or synthetics bonded to each other with heat pressure or resinous materials.
O
Oozing
Refers to the conditions where the sides of a roll become sticky or tacky due to the flowing out of adhesive between the layer of tape.
Over-Run
A quantity of material in excess of the amount ordered. Trade practices permit +/- 10% tolerance for custom over-runs and under-runs.
P
Pattern Coating
Refers to the width and spacing arrangement of adhesive laid down parallel to machine direction, across the width of a pressure-sensitive stock, during its manufacturing.
Peel Adhesion
The force required to remove a pressure-sensitive adhesive tape from a standard test panel at a specified angle and speed under specified conditions.
Permanent Adhesive
An adhesive characterised by having relatively high ultimate adhesion to a wide variety of surfaces.
Plasticizer
A substance added to materials to impart flexibility.
Plasticizer Migration
Loss of plasticizer from an elastomeric compound that is absorbed into the adhesive. The result is a softening of the adhesive to the point of adhesive failure.
Polyester
A strong film having good resistance to moisture, solvents and many other chemicals. It is usually clear and can be purchased in different mil thickness.
Polyethylene
An extruded, tough, stretchy film having limited temperature resistance but good moisture barrier properties.
Polymer
A large molecular chain made up of identical monomer units, to produce a film forming elastomer. This is the base material of films and adhesives.
Polymerization
The chemical reaction by a catalyst, heat, light or electron radiation in which relatively small molecules link up to form a macromolecule.
Polypropylene
A polyolefin plastic similar in properties to polyethylene but with higher temperature capability and greater strength.
Porosity
The extent to which a material will allow air, liquid or other matter to permeate through it.
Post Cure
The phenomenon peculiar to radiation curing after exposure to ultraviolet radiation in which, for a period of time after exposure, the chemical reaction continues to occur.
Pressure-Sensitive
A term used to designate a distinct category of adhesive tapes which in dry (solvent free) form are aggressive and permanently tacky at room temperature and adhere to a variety of surfaces without the need of more than finger or hand pressure. They require no activation by water, solvent or heat and have sufficient cohesive strength so they can be handled with the fingers.
Pressure-Sensitive Tape
A self-adhesive tape consisting of a carrier coated with a pressure sensitive adhesive.
R
Relative Humidity
The percent of moisture in the air at any given temperature that it can retain without precipitation.
Release
The adhesion level between a release liner and the adhesive/carrier combination. High or tight release means the liner is more difficult to remove producing high release adhesion. Low or easy release means that the liner removes readily.
Release Coating
A very thin chemical coating applied to the release liner during its manufacture which renders it suitable to perform its role of allowing an adhesive tape to be unwound prior to use.
Release Liner
A backing coated on one or both sides that protects the adhesive until use. The liner is removed and discarded before application. Most frequently found on double coated tapes and labels.
Removability
The force or conditions required to remove a self-adhesive tape from the substrate to which it has been applied.
Removable Adhesive
A pressure-sensitive adhesive characterised by low ultimate adhesion to a wide variety of surfaces.
Resin
Usually a polymer that imparts tackiness and adhesion to a pressure sensitive adhesive.
Resistance
The ability of a material to withstand exposure to varying conditions without any physical or chemical changes.
Reverse-Roll coating
The adhesive coating is pre-metered between rolls and then wiped off on the web. The amount of adhesive is controlled by the metering gap, and by the rotation speed of the coating roll.
Rewind Slit
A slitting process where a roll of tape is unwound and run through a set of Shear or Score knives to be slit and then wound up into individual rolls.
Roll Form
Die cut parts kiss cut onto silicone release paper and supplied in a roll.
Rubber Based Adhesives
A pressure-sensitive adhesive made from one or more natural or synthetic elastomers, with the addition of tackifiers. These adhesives are characterised by having higher quick stick and adhesion than acrylics, however, they lack ageing and weather resistance.
S
Scored/Split Liner
A cut in the release liner to assist in removal, or to allow correct positioning of larger die cut before total adhesive area is exposed.
Self-Wound
A roll of material adhesive coated on one side with no release liner, and wound on its backing, e.g. masking, transparent and cloth duct tapes.
Self-Wound Tape
Tape construction on which one side is lacquered and the other side coated with adhesive.
Shear Adhesion
The ability of a tape to resist slippage under shear stress. It is measured by applying a standard area of tape to a vertical test panel and suspending a standard weight on the bottom portion of the tape. Measurement is given in minutes till failure and or distance slipped.
Shear cutter
A slitting machine that slits tape with two rotating knives duplicating a scissor action.
Shear Strength
The resistance of an adhesive film to slipping when a load is applied along the plane.
Sheeter
A specific web-fed unit that cuts the web into individual sheets.
Shelf Life
The period of time which a product can be stored under specific conditions and still remain suitable for use.
Silicone
A unique polymer system which can be a very effective release coating or pressure-sensitive adhesive capable of functioning at extremely high temperatures.
Silicone Adhesives
Pressure-sensitive adhesives having remarkable stability through a wide temperature range of –100 deg F to above 300 deg F.
Single Faced
The adhesive is applied to one side of the backing only.
Slip Sheet
A release treated sheet used to protect the edges of rolls from sticking to each other while stacked.
Solvent
In pressure-sensitive technology it is the liquid used to dissolve various adhesive ingredients to facilitate their application to a substrate during coating.
Specification
A document that sets out the requirements for a particular tape or a group of tapes. It normally details the physical properties, performance requirements, general composition, sampling procedure and packing characteristics.
Splice
A point at which two separate lengths of tape are joined together.
Split Back/Bottom Liner
Slitting of the Release Liner introduced to enable easy application of the die cut parts.
Spool Wound
A conversion process where a bulk roll is slit into a narrow width and wound on a core similar to a spool of thread. Spool winding permits very long rolls of converted material. This type of conversion requires specialised equipment.
Spooling
The process of winding narrow slit widths of tape much like fishing line is wound on a reel.
Sprocket Holes
Holes punched in oversize liner to accommodate automatic feed and placing of die cut parts.
Stringiness
A condition of the adhesive in which it feels very soft and gooey and on close examination, relatively long “legs” and “strings” of adhesive can be pulled.
Stripped
Die cut pieces kiss cut on a roll with surrounding waste material taken away.
Stub Roll
A short roll of material.
Substrate
The surface to which a pressure-sensitive tape is applied.
Surface Energy
Surface Energy is a term typically used to describe the ease with which a material can be made pressure sensitive. High Surface Energy materials like metals are usually easier to bond to than Low Surface Energy materials like polypropylene. Surface Energy is measured in Dynes per square centimetre.
Surface Tension
Refers to the molecular energy of a liquid allowing it to flow on a surface. Consider an automobile which has not been waxed. When water contacts the surface, it spreads in large puddles. By comparison, on a freshly waxed car the water will bead up into small spheres. The unwaxed surface demonstrates high surface energy allowing the water to flow. The waxed car is an example of low surface energy. The liquid (adhesive) does not flow out.
T
Tack
The property of a pressure-sensitive adhesive which allows it to adhere to a surface under very light pressure with a minimum of contact time. It refers to the ability of the adhesive to quickly wet out the surface contacted.
Tackifier
A material such as rosin ester added to synthetic resins or adhesives to improve the initial tack of the adhesive film.
Tear Strength
The force to tear a specimen under standard test conditions.
Telescoping
A sideways sliding of the tape layers, one over the other in such a manner that the roll looks like a funnel or telescope.
Tensile Strength
The force required to break a piece of tape by pulling on opposite ends. Results usually expressed in pounds per inch width in the machine direction.
Thermoplastic Adhesives
Adhesives which become softer as temperature increases regardless of how many times they are exposed to heat. Normally pressure-sensitive adhesives are thermoplastic in character.
Thermosetting Adhesives
Adhesive coatings that become rigid or non-meltable when heated with or without pressure and remain set regardless of subsequent temperature cycles.
Tight Release
High or tight release means the liner is more difficult to remove from the carrier/liner producing high release adhesion.
Tissue
Typically referred to as a carrier in a Double Coated product. A tissue carrier can make slitting and die cutting easier, by preventing adhesive flow. Tissue differs from film carriers in that it does allow for some elongation and permits more conformability.
Toxicity
A term referring to the physiological effect of absorbing a poisonous substance into the system either through the skin mucus membrane or respiratory system. Solvents usually have high, medium or low toxicity depending on their concentration. Four hundred parts per million is the maximum amount permissible in the air for safe conditions.
Transfer
Normally refers to “adhesive transfer”. Any tape component which moves from its proper place to some other position during unwind or removal.
Transfer Tape
An unsupported pressure-sensitive adhesive on a release liner that has been release coated on both sides with different release levels.
Two-Sided Tape
A pressure-sensitive tape consisting of a carrier with similar or dissimilar adhesive applied to both surfaces.
U
Ultimate Adhesion
The maximum adhesion available from a pressure-sensitive adhesive, determined by the force necessary to remove a strip of tape from a surface after an extended period of time.
Unwind Adhesion
The force required to remove tape from the roll.
Unwind Side
That side of the tape which is exposed as it is unwound from a roll.
V
Viscosity
A measure of a fluid’s resistance to flow, which influences the amount of ink printed in flexographic printing.
W
Web
The self-adhesive tape, foil, film or other flexible substrate which is unwound from a roll, and moves through a machine for conversion, printing or other related process.
Wetting
The ability of an adhesive to flow uniformly over the laminated surface to which it is bonded.
Z
Zone Coating
Refers to the width and spacing arrangement of adhesive laid down parallel to machine direction, across the width of a pressure-sensitive stock, during its manufacturing.