Pressure sensitive adhesive tapes tests

The PSA tape is manufactured by Compac Industries, Inc. (manufacturer part number 807). The backing is 51 microns thick aluminum foil with a 31 microns thick acrylic pressiare sensitive adhesive. The surface of each sensor was washed with isopropyl alcohol and then blown dry with nitrogen prior to applying the pressure sensitive adhesive tape. Tests were conducted at room temperature using acetone as the liquid. 

Glossary of Terms. Test Methods for Pressure Sensitive Adhesive Tapes, Pressure Sensitive Tape Council, 1996. 

A method of evaluating the adhesive bond to a plastic coating substrate is a tape test. Pressure-sensitive adhesive tape is applied to an area of the adhesive coating, which is... 

In practice the methods of test used most frequently are those that measure adhesion. Wechsberg and Webber17 noted that some pressure-sensitive adhesive tapes adhered more strongly to treated rather than untreated film when tape was pressed in the same manner on samples of film and peeled off under controlled conditions with a tensometer, the force required to separate the tape... 

A simpler test that is used widely also involves adhesive tape. In this, a sample of the treated film is coated with a controlled thickness of a standard proofing ink and the coating allowed to dry completely. A specified pressure-sensitive adhesive tape then is applied under controlled conditions and stripped away the percentage of the ink removed by the tape is assessed by eye. The test has the merit of being easy to perform and when experience has been acquired of assessing the extent of removal of ink it can be remarkably accurate. 

ABSTRACT Dif sion of acetone at the interface of a bonded pressure sensitive adhesive tape was measured using single frequency capachance measurements (SFCM) and a novel interdigitated electrode sensor design. The relative concentration of acetone at the bondline as a function of distance from the edge of the specimen and exposure time was correlated to adhesion loss measured by the 90° peel test. 

Knife incisions were made for cross cut adhesion test through the coating system down to the substrate at three different places. Pressure sensitive adhesive tape was firmly pressed over the inscribed area. Coating removal along the scribed lines was examined and no peeling or removal of paints was found. 

Figure 13. Standard test methods for peel and shear adhesion of pressure-sensitive adhesive tapes...

Figure 14. Standard test methods fiat the tack of pressure-sensitive adhesive tapes A) Rolling-ball tack B) Rotating-drura tack ...

He presented the first training session on PSA tape technology offered by PSTC at the first world conference on adhesive tapes in 1992. Over the years, John has also presented a number of technical papers for PSTC, including Hot-Melt Pressure-Sensitive Adhesives, Practical Aspects of Formulating and Processing, Tack, The History of the Adhesive Tape Industry and Alternate Methods of Testing Pressure-Sensitive Adhesive Tapes. ... 

In 2000, the PSTC published Johnston s book, Pressure-Sensitive Adhesive Tapes A Guide to their Function, Design, Manufacture and Use. The widely recognized volume is essential for those in the tape industry and includes information on how PSAs work, PSA formulations, tape backings, tape design, and tape testing. It is to the vast majority of others who daily keep the adhesive tape industry alive that this book is both targeted and dedicated, he says of the book... 

Attention is drawn to those that do not conform to the above requirements, although they may well have other advantages that make them useful tests. As a purely practical matter, some tests are particularly suitable for soft adhering layers, such as pressure-sensitive adhesive tapes, and others are more appropriate for rigid, structural adhesives. This aspect should be obvious from the discussion in each case. 

Martens JM, Clemens LM, Zigman AR (1980) Acrylic-type pressure sensitive adhesives by means of radiation curing. US Patent 4,181,752 Paul CW (2002) Hot melt adhesives. In Chaudhury M, Pocius AV (eds) Surfeces, chemistry and applications adhesion science and engineering. Elsevier Science B.V, The Netherlands, pp 711—757 Pocius AV (2002) Adhesion and adhesives technology, 2nd edn. Hanser, Munich, p 151 Pressure Sensitive Tape Council (2007) Test methods for pressure sensitive adhesive tapes, 15th edn. 

Pressure-sensitive adhesives are used in a great variety of applications, most commonly for adhesive tapes. In that case, they have to be tested by static shear test or dynamic shear test The difference between these two methods is that in static shear test a standard force is being applied to the test specimen and the adhesive failure is reported as the time it takes for failure to occur. The dynamic shear test involves a force being applied to the PSA tape at a specific rate of speed (typically 0.25 mm or 0.1 in. per minute). The value reported is as the peak force per unit area (Ib/in, also abbreviated as psi, and in SI units MPa) required to cause adhesive failure. The standards for adhesion shear tests are ASTM D3654, ISO EN 1943, and PSTC-107.i i ... 

Test Method for Impact Strength of Adhesive Bonds Test Method for Tensile Properties of Adhesive Bonds Test Methods for Pressure Sensitive Adhesive Coated Tapes Used for Electrical and Electronic Applications... 

This test method is preferably used for the comparative evaluation of adhesives and surface pretreatment methods, since it enables the indication of the differences in the adhesive and cohesive behavior of the adhesive layers with high sensitivity. Pressure-sensitive adhesives (adhesive tapes, adhesive labels) are also tested according to this principle. 

It is assumed in almost all cases, that any pressure-sensitive adhesive to be tested has already been applied to a flexible carrier, which is either in tape form, or which can be cut into tapes for testing, virtually all test methods making this assumption. If this is not the case, then it would be necessary to coat the adhesive onto a suitable flexible carrier, usually 25 pm polyester film, which may need to be suitably pre-primed, the prime coat used depending on the adhesive type. The coat weight chosen should be that used for the practical application of that adhesive, or if this adhesive is still under development, then a series of coat weights can be run, to determine which provides optimum performance. An exponential relationship will be found between coat weight and resulting adhesion. 

The test methods presently used to evaluate the adhesion of pressure-sensitive adhesives to release liners are modified adhesion tests, such as the 180° or 90° peel test, with the liner adhered to a test panel, or a T-peel test, where the sample is freely suspended while the tape is peeled at a controlled rate from the release liner. The values obtained by the latter method are alfected considerably by the stiffness of the liner, which alters the angle of peel. 

In instrumented creep tests taken to failure, one learns not only how long specimens last but also how deformation increases throughout the creep process. For lap joints, delay times have been seen in creep tests, probably due to the increasing uniformity of the shear stress state, as predicted by the shear lag model as the creep compliance of the adhesive increases with time. In other situations, no such delay time is seen. A schematic illustration of a creep curve for an adhesive bond consisting of a butt joint bonded with a pressure sensitive foam tape is shown in Fig. 2, exhibiting classical primary, secondary and tertiary regions of creep behaviour. 

Pressure-sensitive adhesives are normaiiy supported on backing materiais and soid as tapes, iabeis or sheet products. Their adhesion properties are often tested in the form of tapes cut directiy from such products. Since most adhesion properties are influenced by the nature and thickness of the adhesives and backing Aim iayers, the resuits obtained cannot be regarded as intrinsic properties of the pressure-sensitive adhesives, but are in fact properties of the composite tape. 

Standard tests used to characterize the adhesion properties of tapes are for the assessment of shear strength (see Shear tests) (the ability of a tape joint to resist a load applied in the shear mode), peel strength (see Peel tests) (the resistance of a tape joint to peeling under specified conditions) and Tack (the ability of a pressure-sensitive adhesive to form a bond immediately on contact with another material). There are many standard test specifications laid down by different authorities to assess these properties and many differences in detail between them (e.g. see Appendix). No attempt will be made to describe them comprehensively, but the principles of the tests will be discussed separately. 

As with other pressure-sensitive adhesive tests, the temperature is an important variable and tests are typically carried out at room temperature. A variation on this method is the SAFT test (shear-adhesion-failure temperature) in which the test apparatus is placed in an oven where the temperature is set to rise at 4.5°C/min. The temperature at which the tape fails is recorded as the SAFT value. 

Six micrometre PEEK film has recently replaced polyethylene terephthalate (PET) as a cover film for thermal-acoustic and burn-through insulation. PET failed the new FAA flame performance tests and alternative materials such as PVDF and polyimides were too dense or not available in the required film thicknesses. The film is installed using PEEK tape coated in an acrylic pressure-sensitive adhesive. PEEK fibre also finds application in high-temperature acoustic blankets based on the Helmholtz resonator effect [2]. 

---