This is a discrete number generated by the manufacturer to allow traceability of all raw materials used in the manufacture of a product. Their own internal quality procedures will determine what constitutes a batch and when the batch number has to be changed, however, it allows the manufacturer to identify precisely what components/ingredients were used from various suppliers to create their product. If correctly recorded it is a vital tool for identifying, isolating and quarantining defective stock.

Where tapes are being used for bonding clear or translucent materials (e.g. plastics, Perspex, screen printing) or mounting media in windows, clarity can be an important requirement.

Certain applications may state that a Certificate of Conformance is required for the materials being used. A CofC cannot normally be supplied after the goods have been manufactured since it requires special testing at the time of manufacture to ensure that the product conforms to a particular specification. This will normally by some form of third party specification such as a Military Specification (Mil. Spec.). A CofC will relate exclusively to a particular batch number. A Letter of Compliance, on the other hand, can be tendered by the manufacturer after the date of manufacture and will simply confirm that the product has been manufactured to comply with a particular specification, although no specific batch testing. These documents are normally only requested for critical applications.

When referring to double sided tapes (that are not transfer tapes) this is the medium onto which the adhesive is coated.

This is a process for applying a coating of adhesive whereby the adhesive is pressed between two rotating cylinders into a thin layer and then coated onto the carrier. This is the most common way for making cloth tapes and many rubber based adhesive tapes.

This type of adhesive has relatively low cohesive strength but high adhesive strength, it has excellent ageing characteristics and is very resistant to moisture, oxygen, ozone, and weathering. Consequently it tends to get used for gasket and sealing type applications. Butyl rubbers also offer good damping and vibration absorption characteristics.

See spool.

If the tape is being used for some form of temporary holding application then it may be desirable for it to clean remove from one or both the surfaces. For a tape to clean remove the adhesive needs to be better bonded to its carrier than it does to the bonding surface and the carrier to have greater structural strength than the bond strength. Temporary bonds require an adhesive to have good cohesive strength but only moderate adhesive strength. Note: Clean removal from painted surfaces and plasterboard will be dependent on the quality of the keying of the paint or board to their underlying substrate.

This is the mass of adhesive applied to a unit of area. It may also be referred to as Adhesive Mass or Mass Weight and is normally expressed in grams per square metre (gsm)

This is the ease or ability of a tape to conform and make direct contact with the underlying substrate without creasing and folding or air pockets forming.

This is a process used to physically treat the carrier surface to be coated to promote the keying of the adhesive to its carrier. It is most effective when conducted in-line immediately prior to the coating, since its effect will wear off with time. It is particularly relevant in the treatment of low surface energymaterials, such as polyethylene, prior to adhesive being coated.

This is a commonly used process within the adhesive tape industry to modify the performance of adhesives. It can be applied to both rubber and acrylic adhesives and involves subjecting the adhesives to either chemical or gamma irradiation treatment. The process aligns the molecules in the adhesive and links them rather than them being mobile and randomly orientated and has the effect of firming the adhesive. The greater the degree of treatment the lower the tack level but the higher the cohesive or shear performance and also the greater the resistance to temperature, UV light, chemicals and ageing.

Where two dissimilar rigid surfaces are being bonded it is very important to consider this phenomenon. All materials will expand and contract at different rates when subjected to a temperature change. For short lengths the difference will probably be negligible but the longer the length or area of the two surfaces being bonded the greater the forces that will be generated by their different rates of expansion or contraction. To absorb these tensions the tape needs to be able to "give" and this can be achieved either through a high coat weight of adhesive or a flexible adhesive carrier, such as a foam. Metals tend to have relatively high levels of expansion when compared to glass or stone. One may even get significant differences between dissimilar plastics and synthetic materials. If the force generated by this dissimilar rate is greater than the bond strength then it will weaken the bond leading to failure.

Relating to an adhesive system where water is used as the method for dissolving and spreading the adhesive on the carrier/release liner.

Dwell time is the period taken to achieve maximum bond strength. The bond strength will normally improve over a period of time. Some manufacturer's product specification sheets give figures for the bond strength after a given period. Normally it will take up to 24 hours to form maximum bond strength and after that period or "dwell time" there will be little improvement or change. As a general rule, the softer the adhesive type and the thicker the coat weight (the thickness of the adhesive) the quicker it will achieve its maximum bond strength. As a very rough guide, if maximum bond strength for any given adhesive is achieved within 24 hours of the tape's application, then a bond strength of between 60 and 80% is achieved within 1 minute and 75 to 90% within 20 minutes.

This test measures the ability of a test sample of the tape to resist a moving force along the plane of the bond with the force applied relatively quickly, as opposed to a static load. The test is conducted using a specified area of tape on a specified surface at a specified temperature. After a dwell period, the two plates are separated at a rate of 300mm per minute and the Force required to break the bond is recorded in Newtons per square centimeter N/cm2. This test best represents the forces a bond will be subjected to when subjected to a pulling motion.

This test is sometimes called the "T" Block test and measures the ability of the sample to resist a relatively quickly applied load at right-angles to the plane of the adhesive bond. The test conditions and results are recorded as for dynamic shear in N/cm2. This test best represents the forces a bond is subjected to when a tape is used for attaching items to roofs or ceilings.

This is a problem common with transfer tapes whereby the adhesive oozes and then fuses with adjoining layers of tape. The problem is exacerbated where the transfer does not have a glass fibre flock and where the tape is poorly slit (adhesive drag in slitting). The effect of this is that the tape will not unwind easily and will become very hard to apply. Care is always required when handling rolls of transfer tape to try and reduce this tendency tape should be stored or left on a release liner and not directly on a benchtop.

Normally a rubber-like substance which can easily be deformed by force but will then return to its original shape. Elastomers are one of the key ingredients of most pressure sensitive adhesives.

Relating to an adhesive system where water is used as the method for dissolving and spreading the adhesive on the carrier/release liner.

This normally takes the form of glass fibres that are added to the adhesive batch when making transfer tapes to give the adhesive some dimensionable stability. This makes the transfer easier to tear and convert and limits the adhesive flow.

Federation Internationale des Fabricants et Transformateurs d'Adhesifs (The International Association for Self-Adhesive Labels & Related Products) a representative group for the industry.

This refers to a tape that has a release liner wider than the actual coat width of adhesive. The dry edge may be one or both sides and simply facilitates removal of the release liner when required. e.g. seals on mailing envelopes. See also pattern coating.

These are small circles on the adhesive's surface caused by air being trapped between the adhesive and the next layer of tape or from the evaporation of solvent during curing of the tape. This effect will tend to diminish with ageing and although sometimes unsightly does not signify any defect or lack of coating in the tape. Where clarity is vital then consider a solventless adhesive system.

These high performance tapes are not foams in the true sense but a foamed adhesive with small glass balls to give it internal strength. It has a high density and is non-porous and exhibits very high cohesive and internal strengths. These types of adhesives are very stable and offer superior bond strengths on a wide range of surfaces. The foamed acrylic core is cured using UV light and is sometimes referred to as solventless adhesive however it may be subsequently coated with a solvent based adhesive to modify or improve its performance.

This is where consecutive layers of tape in a roll become separated, thereby forming a gap. Gapping is unsightly and will affect the consistency of the unwind tension, however, it will not materially affect the performance of the adhesive in the short term. If the roll is left unprotected then it will be more prone to oxidization (drying out).

The majority of tape is applied by hand and so it can be an important feature that it can be easily and cleanly torn by hand. The ease with which a tape can be torn is a function of the release liner and the adhesive's carrier. Whilst certain tapes such as transfers and foams are easily torn they do not usually tear cleanly by hand for different reasons. Where tapes are being used continuously e.g. print finishing shops, curtain & blind trade, sailmakers etc. it is vital that the product exhibits good tear characteristics.

The ability of a tape to retain its cohesive strength under increased temperature, generally speaking, silicon adhesives offer the best thermal resistance and hot melt rubbers the least.

This is the ability of a tape to withstand slippage under shear stress. It is normally measured using a static shear test where a fixed area of tape is used to suspend a fixed weight in the vertical and then the time taken for the bond to fail is measured (as opposed to a dynamic shear test, where the tape is put under an increasing load until the bond fails).

This is an adhesive type that is coated by heating it to a temperature where it flows, on cooling it forms a conventional pressure sensitive adhesive. Hot melts are predominantly rubber based adhesive systems but other types do exist. Inevitably, this type of adhesive system tends to exhibit poor thermal stability but is normally economical and has high initial tack levels.

Impact resistance and vibration absorption may be an important requirement, for example, in the transport industry. Products best designed to cope with these types of forces have adhesives that age well and so retain their tack levels, a high coat weight of adhesive and a carrier that is flexible and conformable.

This term relates to the quick stick characteristics of the adhesive. It is an indicator of how easily a tape will form an initial bond with a surface. Generally the initial tack of the adhesive is a function of the type of adhesive and its coat weight (see also Adhesive Wet Out and Adhesive v Cohesive Strength sections). The nature of the product's initial tack will have implications for other characteristics.

This is a piece of paper or card that is used to separate rolls of tape when they are packed. The interleave needs to have a surface treatment that adhesive will not stick to e.g. silicone or PE (as for the release liners on double sided tapes). The use of interleaves helps prevent edge bleed and makes the tape rolls easier to separate and apply. Also called Slip Sheets.

This is the bulk form that tape is normally stored in when it comes off the coating line, the width is dependent on the size of the base materials and the width of the coating heads. The length is largely determined by the gauge and density of the tape. Jumbos can be converted directly into rolls of tape by a slit rewind process or else logged to shorter lengths and then lathe slit.

This is Du Pont's brand name for their polyamide film that is widely used for high temperature masking and insulating applications. It is invariably coated with a silicon based adhesive to confer high temperature properties on the tape.

This is a coating applied to the carrier or backing prior to the adhesive being applied and causes the adhesive to better key or bond to one side of a carrier/backing than the other. Similarly a release coat can be applied to the opposite surface to prevent the adhesive bonding with it when the tape is in roll form. Corona treatment of the surface can have a similar effect as applying a key coat.

A term to describe a sulphate wood pulp paper (tan or brown in colour).

This is a simple splice where the material is simply overlapped so one has a section of double thickness of the product.

Rolls are slit from a log of material to the required width on a rotating mandrel by use of a circular blade which is also rotating. This method of slitting is relatively slow but far more flexible than slit rewind. It is also called Lever Cutting.

This is where the adhesive stretches and strings when put under tension. This generally suggests that the adhesive lacks cohesive (internal) strength and can be symptomatic of problems such as plasticiser migration.

This is where a tape lifts away from a substrate to which it has been applied of its own accord. The reason for this could be one or a mixture of the following possible reasons: insufficient initial pressure applied, ambient conditions unsuitable at time of application, surface not properly cleaned prior to application, product unsuitable for this particular application or tape is not up to specification.

This term refers to the side of the tape to which the release liner is normally attached in a double sided tape, as opposed to open side.

This is the tape in the required length at full width and is created from rewinding the bulk material (jumbo) to the required length on a logging/rewinder machine. Logs can then be slit to the required width to create a roll of tape.

The bond strengths that appear on specification sheets and in these tables relate to results obtained from testing on a smooth stainless steel test panel in laboratory controlled conditions. Stainless steel, like most metals, is receptive to forming a bond with adhesives and these types of surface are termed high energy surfaces. However, there are a variety of materials that are less receptive to forming a bond due to their molecular structure. These so called Low Energy Surfaces exhibit a weak polarity and so are less able to influence and attract the intermolecular forces present at the surface of the adhesive. Such surfaces require adhesives with a high initial tack, consequently one has to look to the rubber based or modified acrylics or butyl to form a bond with these types of finish. If these types of tape will not give the performance required then one may have to consider using a chemical primer on the surface to make it more receptive to bonding. Listed below are the surface energies of some common products:

This is the direction parallel to the unwind direction of the roll, as opposed to cross direction.

This is a document produced by the manufacturer that details all/any of a product's potential hazards and how they are to be reacted to or treated. They may also be termed a Health & Safety Data Sheet.

This is the tendency of a material to return to its original shape or form after stretching or deformation. It is this property of tapes such as self-amalgamating and plasticized PVC's that make them suitable for electrical insulation applications. The memory in a tape can be utilised to give structural support e.g. grafting in horticulture.

A Mil is 1/1000 of an inch and is an imperial measurement that still is commonly used in US specifications. It is normally used referring either to gauge or coat weight of adhesive. Select the Conversion Chart button on the website to convert this and other imperial measurements to metric.

This is an acrylic adhesive system that has additives such as tackifiers and resins introduced to it to modify or improve its characteristics for a particular application. In this process the chemist is trying to achieve the best compromise between adhesive and cohesive strength for a particular application.

A monomer is the basic building block of hydrocarbon chains and are joined together to form a polymer.

This is the Du Pont brand name for polyester or PET, a strong, clear film used as the backing for both single and double sided tapes.

National Association of Testing Authorities (Australia) an independent third party testing authority.

This is derived from latex rubber trees, as opposed to synthetic rubber, and is a key ingredient of many pressure sensitive adhesives imparting both tack and adhesive properties.

The Newton is defined as, that force which, if applied to a free body having a mass of 1 Kg, would give the body an acceleration of one metre per second per second. I Newton is equal to a force equivalent to 0.102 Kg or 3.6 Ozs under standard gravity.

These are materials, either tissue paper or synthetic, where the fibres are randomly orientated and are bonded to each other either by pressure or some resinous material. They are widely used as carriers for double sided tapes since they give the tape some dimensionable stability and yet are highly conformable and act as very good carriers of an adhesive.

This is where an adhesive residue is left on the uncoated surface of the tape on unwind. It can be caused by a number of issues such as: poor release coat, poor key coat, over age tape or application at high temperature causing the tape to leg and offset.

This is the tendency for the adhesive to flow out at the edge of a roll and is a function of the cohesive strength of the adhesive, the mass of adhesive, the tension in the roll and the temperature it is stored under.

This is the side of tape that does not have the liner on it or is the adhesive side for single sided tapes, as opposed to closed or linered side.

Manufacturer's specifications will normally show an operating temperature range for a tape once a bond has been formed. This should not be confused with the application temperature. Once an adhesive has wetted-out onto the bonding surface and a dwell time of 24 hours has elapsed then the bond strength should maintain its integrity across the published range, albeit with a possible tail-off at the extremes.