Pressure-sensitive test methods

Shock Sensitivity Shock-sensitive materials react exothermically when subjected to a pressure pulse. Materials that do not show an exotherm on a DSC or DTA are presumed not to be shock sensitive. Testing methods include ... 

Franz, R. 1993. Permeation of volatile organic compounds across polymer films. Part I Development of a sensitive test method suitable for high barrier packaging films at very low permeant vapour pressures. 

Piping required to have a sensitive leak test shall be tested by the gas- and bubble-formation testing method specified in Art. 10, Sec. V of the ASME Code or by another method demonstrated to have equal or greater sensitivity. The sensitivity of the test shall be at least (100 Pa mL)/s [(10 atm mL)/s] under test conditions. If a hydrostatic pressure test is used, it shall be carried out after the sensitive leak test. 

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

Laminated tapes In more general use now than pressure sensitive tapes are tapes consisting of polyvinyl chloride or polyethylene films in conjunction with butyl rubber. These tapes are applied with an adhesive butyl rubber primer. Thicknesses of up to 0-75 mm are in use and loose protective outer wraps of p.v.c. or polyethylene sheet are commonly applied. Tape quality control is exercised with reference to ASTM standard test methods and may include water vapour transmission rate and elongation. 

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... 

Jaffe et al (Ref 3), in the course of determination of the shock pressure required to initiate detonation of an acceptor in the shock sensitivity test, found that the velocity of the front as sensed by the pressure probe method, falls behind the true velocity of the shock front as the shock is attenuated. It has also been found that the maximum transmitted shock velocity generated by the two Tetryl pellets and measured in Lucite is 4.6mm/frsec. Shock velocities determined by optical method, shown in Table 3, p 25, run between 2.701... 

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 ... 

Tack is, of course, of great importance for adhesives and many methods have been used. A summary of work on testing and finite element analysis of adhesive tack has been given136 and it has been questioned whether the methods used for pressure sensitive adhesives really work137. 

A typical indication of leakage is the inability of the leaking system to achieve the expected working pressure. Pressure-rise tests are frequently carried out to assess the magnitude of the problem (Examples 4.3, 4.5-4.7,4.9). A convenient and highly sensitive method of leak detection and quantification uses He as a tracer gas and a He leak detector (MSLD). Some aspects of practical leak detection using MSLD were discussed (Examples 4.10-4.12). 

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... 

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... 

D 2979 Test Method for Pressure Sensitive Tack of Adhesive Using an Inverted... 

D 3121 Test Method for Tack of Pressure Sensitive Adhesives by Rolling Ball... 

D 5375 Test Methods for Liner Removal at High Speeds from Pressure Sensitive... 

Both rupture disks and breaking-pin devices are sensitive to temperature. The manufacturer should always be consulted for applications that are not at ambient conditions. Since non-reclosing pressure-relief devices can be used only once, the set pressure is determined by testing a sample of the devices out of each manufactured batch. Pressure-relief valve test methods are specified in AS ME PTC 25-2001. 

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