Quick stick test

The methods to evaluate PSAs include the rolling ball test (ASTM D3121, PSTC-6, BS EN 1721), loop tack test (ASTM D6195, FINAT Test Method 9, BS EN 1719), and quick stick test (PSTC-S). ... 

Figure 5 Quick-stick tack testing (a) compressive effect of 90° peel (b) loop tack testing.

Quick stick is a measure of how readily a pressure sensitive adhesive adheres to a test surface with no applied pressure other than the weight of the adhesive backing. The test strip is peeled immediately after application. 

Primary tack measurement techniques include probe tack tests, loop tack, quick stick, and rolling ball techniques. These techniques are illustrated schematically in Fig. 22.12. 

Tack is defined as the limiting value of the adhesion as the contact time approaches zero. Targets for tack measurements are shortest possible contact time and lowest possible contact pressure. With this aim, a number of methods have been developed [53, 54]. The best known tack measurement methods are quick-stick, probe tack, Zosel tack and rolHng ball ]27]. AH these methods are ultimately a refinement of the subjective finger test, which stUl plays significant role in forming a qualitative practical opinion ]27]. 

In the quick-stick method corresponding to FINAT test method No. 9, a test strip is formed into a loop, brought into contact with a glass plate and then immediately peeled off again, as shown in Fig. 8-16. 

This FINAT method differs from the PSTC (PSTC-5) quick-stick method, in which peeling is carried out at an angle of 90° without formation of a loop [55]. The Tag and Label Manufacturers Institute (TLMI, Iowa City, lA 319-337-8247) specifies a loop tack test and within their manual, includes a host of useful TAPPI and ASTM methods for testing paper and plastic film substrates used in pressure sensitive labels, respectively. 

The advantage of the quick-stick methods compared with other tack measurement methods is that the test can be carried out in any mechanical test machine with only minimal contact pressures. Disadvantages of the method include a relatively long contact time, different contact times within a test area and different contact areas. Moreover, the peel angle is not constant in the FINAT method. 

The scatter in the values after exclusion of outliers is 3-38 % of the mean, depending on the test. Apart from the very low scatter in the quick-stick method, the scatter is lower for methods with longer contact times. Prerequisites for such results are very uniformly defined test specimens and exact compliance with defined test conditions [27]. 

Immediately following the initial assembly (and at any other time leaks are suspected), the box and purification train should be tested for leaks. A quick test for leaks is to pressurize the dry box until the gloves stick straight out. The gloves should remain in this position for several hours if no leaks are present. If leaks are indicated, testing is most easily accomplished while the box is pressurized. If the inert atmosphere is helium, the preferred method is the helium sniff test. All joints, welds, and connections should be checked. In the absences of a helium-sensitive probe or if the inert atmosphere is other than helium, the bubble method may be used a small amount of soapy water is placed on leak-prone welds and joints and the appearance of any bubbles is noted. 

Aspartate transaminase (AST) or the equivalent serum glutamic oxaloacetic transaminase (SGOT) and alanine transaminase (ALT) or the equivalent serum glutamic pyruvic transaminase (SGPT) are useful indicators of liver conditions such as alcoholic liver disease (Cohen and Kaplan, 1979). A multiplexed, paper-based microfluidic assay designed for quick, semiquantitative measurement of AST and ALT in a hn-ger-stick specimen has been tested clinically (Pollock et al., 2012). Such paper-based techniques have also been supplemented by optical detection (Swanson et al., 2015). Microfluidic channels combined with electrochemical sensors have also used to measure ALT and AST (Song et al., 2009). 

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