Technical Tape Info
TAPEOLOGY
What are the different components of a tape?
BACKING
A backing (or carrier) is a thin, flexible material that can be coated with adhesive. It can be made of paper, fabric, film, foam, foil, non-woven material or laminate.
ADHESIVE
Typical adhesive types are natural or synthetic rubber, acrylic, and silicones.
PRIMER
A primer is used to increase the bond of the adhesive to the backing. The use of a primer assists in keeping the adhesive on the backing when a tape is removed.
RELEASE LINER
A liner is typically used for double sided tapes, but is sometimes found on single sided tapes as well. Siliconized paper is the main type of release liner. Siliconized film is also used in applications requiring greater flexibility and high tensile strength.
RELEASE COATING
A release coating is applied to the backing and allows the tape to unwind from the roll. Without a release coating, the tape would adhere to its own backing and would not unwind.
HOW IS PRESSURE-SENSITVIE TAPE MANUFACTURED?
COMMON BACKINGS/CARRIERS AND CHARACTERISTICS Film (Plastics)
Polypropylene:
Crystalline thermoplastic resin. It’s plastic commonly used as backing for packing tapes. BOPP- Bi-axial orientated polypropylene, (stretched both machine direction and cross direction), tensilizes polypro MOPP- Mono-axial orientated polypropylene, (stretched machine direction only) and carriers on economy double coated tapes. Very good moisture and chemical resistance. This product is one of the less expensive plastics.
Polyester (PET):
Another member of polymer family of plastic tape. The strongest of synthetic films it has excellent electrical properties and very good moisture resistance. Also known as Mylar tape, a trademark name from one of our competition.
Polyethylene:
A polymer of ethylene. This product exhibits good resistance to moisture and chemicals having good insulating properties. It has inherent stretch and very good low temperature characteristics.
PVC (Polyvinyl Chloride):
Emulation polymerization of vinyl chloride. A common backing for more expensive packing tape and a stronger carrier in double coated tapes.
Vinyl (Plasticized Polyvinyl Chloride):
A tough durable plastic film having excellent electrical properties. Its high stretch is made possible due to the addition of plasticizers, which allows the vinyl molecules to slide over one another.
UPVC (Unplasticized Polyvinyl Chloride):
A tough durable plastic film. The main difference between UPVC and PVC is UPVC is not very stretchy.
Cellulose (Acetate):
A thin transparent moisture resistant film. Fluorocarbon (Fluorofab): A film with very high and low temperature limits, excellent electrical characteristics, and a very slippery,non-stick surface. Scientific name; polytetrafluoroethylene. Nylon: A very strong film with high oil and gas resistance.
Paper
Crepe:
The most common paper used in masking tapes. This product has small folds in it to increase its stretch. Tissue: Used as an earner in double sided paper tapes. This material is thin and hand tearable. This is a non-woven product. Kraft: A sulphate wood pulp paper (for tapes these are usually saturated). Common in water activated tape (WAT) and can be reinforced. Flatback: A smooth kraft paper. Rope: A smooth flat paper made of hemp fibers for high tensile strength. Not very common in the market these days.
Cloth
Plain: Fabric woven from cotton, glass or other fibers, without being further treated. Sized: Fabric, usually cotton, treated to give added stiffness and easier handling. Coated: Fabric with rubber or plastic back coating to give increased moisture resistance and durability.
Foam
Latex Foam: A fairly firm foam made from natural rubber. Vinyl foam: A very soft foam made from PVC. Can be closed cell or open cell. Urethane Foam: An excellent shock absorbing synthetic foam.
Metal Foils
Aluminum:
Unaffected by extreme humidity, this is an excellent heat reflector.
Lead:
Excellent weather resistance and dead crease.
Copper:
Used in printed circuits and other electrical applications due to its conduction characteristics. (Kapton Tape)
There are many other backings/carriers that have not been discussed however this should help you to understand some of the more popular materials and open your mind to the great big world of tapes!
Abrasion Resistance
The ability of a tape to withstand rubbing and still function satisfactorily.
Backing
A relatively thin flexible material to which the adhesive is applied. Theoretically any material that is reasonably flat, thin and flexible can be used in backing.
Carrier
A webstock that holds a pressure sensitive adhesive, especially used to refer to double faced or double coated tapes.
Conformability
Ability of tape to remain in full contact with the surface of any irregularly shaped object without puckering or creasing.
Cross-Linking
Developing a three-dimensional molecular structure in an adhesive normally activated by heat or irradiation. An improvement in shear resistance, high temperature resistance, and oil or solvent resistance will normally result.
Delamination
A separation or splitting of the tape such as separation of the backing into two distinct layers, separation between laminations of a tape consisting of more than one backing, separation between filaments and backing of a filament reinforced tape, or separation of the adhesive from the backing.
Double Coated
An adhesive application to both sides of a backing.
Elastic Memory
Tendency of some tapes’ backing to revert to its original length after becoming elongated.
Elongation (stretch, ultimate elongation) The distance a tape will stretch in the machine or cross direction before breaking under controlled conditions, expressed as a percentage of original length. Elongation is not necessarily an indication of conformability.
Face Stock
Any paper, film, fabric, laminate or foil material suitable for converting into pressure sensitive material stock. In the finished construction this web is bonded to the adhesive layer and becomes the functional part of the tape construction. Another name for backing on a single faced tape.
Flame Retardant (also Self-Extinguishing, Fire-Resistant) Ability of tape to withstand exposure to a flame. Flame retardant materials burn in direct contact with a flame, but combustion is not maintained when the flame is withdrawn. “Non-flammable” materials do not burn even when in contact with a flame.
Filaments
Thin, longitudinal yarns or threads of glass, polyester, nylon or other high strength materials.
Flexibility
Ability of a tape to be conformable or pliable during application, particularly in low temperature applications.
Gloss
A light reflection characteristic of tape backings, usually expressed by such terms as glossy, low gloss, matte, etc. Measured on a scale of 0 - 100.
Impact Resistance
Ability of an adhesive tape to withstand sudden shocks and loads, especially important for tapes used in packaging.
Moisture Absorption
Measures the quantity of moisture absorbed and retained by a tape under specified conditions.
Opacity
The ability of a tape to prevent the transmission of light. Measures on scale of 0 - 100%, total opaque is 100%.
Printabilty
Ability to accept printing inks and then maintain graphic presentation after winding and application.
Reinforced
Material sandwiched between the backing and the adhesive for added strength.
Saturation
Adding materials to the backing for greater internal strength and resistance to environmental elements.
Single Faced
A tape to which a pressure sensitive adhesive is applied to only one side of the backing.
Substrate
The surface material on which tape is to be applied.
Surface Energy (surface wetting ability) The measure of surface tension in dynes. The lower the surface energy of a substrate, the more difficult it becomes for an adhesive or coating to wet out (stick to) that surface.
Surface Treating
Any method of treating a polyolefin (poly forms of plastic) so as to alter the surface and render it receptive to inks, paints, lacquers, and adhesives such as chemical, flame and electronic oxidation.
Tensile Strength (breaking strength) The force required to break a unit width of tape by controlled pulling on opposite ends of the piece. MD = Machine Direction. TD= Transverse Or Across Direction.
Thickness (caliper, gauge) The perpendicular distance from one surface of either a tape, backing, or adhesive to the other, usually expressed in mils, thousandths of an inch or millimeters. This is usually measured under controlled slight pressure with a special gauge.
COMMON ADHESIVES AND CHARACTERISTICS:
ADHESIVE: Typical adhesive types are natural or synthetic rubber, acrylic, and silicones. In case you were wondering, adhesive is the sticky stuff on the back of the tape.
Rubber: The original adhesive found on bandages in the First World War. Did you know that’s where tape originates? There is still some debate on which company made tape first. Like everything else in the tape world, there are different kinds of rubber adhesives. They couldn’t make it easy. The first, in terms of tack is synthetic rubber followed by hot melt rubber and the Cadillac, natural rubber.
Everything You Wanted To Know About Rubber. • Rubber has the best initial tack (however acrylics have come a long way in the past few years and some may challenge this statement). • Rubber will, over time, dry out and turn to a powder. • Rubber will yellow (especially in sun light) so it is not recommended for any clear (window) applications.
Acrylic: A chemistry experiment gone well. Acrylic has taken the tape market by storm over its relatively short time in existence. Those science boys really hit a hot product. Once again, there are a few different variations of acrylic including water bases and emulsion.
Everything You Wanted To Know About Acrylics. • Initial tack may be lower then rubber but acrylic set up (bond to the substrate) in 24 - 48 hours, making a very strong bond. • It will not yellow (depending on chemical make-up) or lose its form, making it ideal for permanent applications. • High temperature resistance.
Silicone: The most expensive adhesive but when you need it, nothing else will do!
Everything You Wanted To Know About Silicone. • The only adhesive that will stick to a silicone (usually coated) substrate. • The highest temperature resistance in adhesives.
FEATURES AND TERMS RELATING TO ADHESIVES:
Adhesion To Backing
The bond produced to the backing of the same tape or another tape backing.
Adhesive Deposit Or Residue
Adhesive that is pulled away from the tape upon removal and remains on the surface to which it has been applied.
Adhesive Transfer
The transference of adhesive from its normal position on the tape backing to a surface to which the tape was attached, either during unwind or removal.
Blocking
Adhesion between the sheets of the plies of rolls of coated material, usually due to extreme conditions of pressure, temperature or humidity.
Coating Weight
The weight of a coating per unit area. In Si-units expressed as grams per square meter (GSM).
Cohesion (cohesive strength, internal bond) The ability of the adhesive to resist shear stress and splitting from backing or carrier. Good cohesion is necessary for clean removal.
Cure
To alter the properties of an adhesive by chemical reaction, which may be condensation, polymerization, or vulcanization. Usually accomplished by the action of heat and catalysts or UV, alone or in combination, with or without pressure.
Elasticity
The ability of adhesive films and or adhesive to recover their size and shape after deformity.
Elastomer
An elastic, polymeric substance, such as natural or synthetic rubber.
Hot Melt (pressure sensitive adhesive) A pressure sensitive adhesive, applied to the backing in hot liquid form, which then cools to form a conventional pressure sensitive adhesive.
Oozing
A “squeezing out” of the adhesive from under the backing. Occurrence when a tape is in a roll form causes the edges of the roll to become tacky.
Pattern Coated
A term that refers to the width and spacing arrangement of strips of adhesive laid down parallel to machine direction and across the width of pressure sensitive stock during its production.
Plasticization
The softening of an adhesive when exposed to migrating plasticizers or oils.
Wet Grab / Tack / Quick Stick
Ability of a tape to create an immediate bond, with a measurable strength, during the contact of the adhesive with the substrate, without applying external pressure.
Cross-Linking
Development of a three-dimensional structure within an adhesive in order to improve bond strength and resistance to temperature, oil or solvents.
Delamination
A separation of the backing and the adhesive into two distinct layers (also referred to as adhesive transfer).
Shear
The ability of an adhesive to resist creep or slippage.
