Rolling ball 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). ... 

Rolling Ball Test 180° Peel Test 20° Hold Test... 

The rolling ball test for tack usually involves allowing a stainless steel ball, diameter c. 12 mm, (or sometimes a table-tennis ball) to accelerate down a ramp of fixed (21.5°) inclination on to the horizontal adhesive surface. The distance travelled by the ball on the adhesive surface before arrest is taken as an inverse of tack for that surface. For a given adhesive, the ratio is often found to be constant, where h is ramp height and... 

Tack of Pressure-Sensitive Adhesives by Rolling Ball, Test for (D 3121)... 

In contrast to the other tack measurement methods mentioned above, the rolling ball test requires simple equipment and is easy to carry out. The main difference to the other tack measurement methods is the fact that the rolling ball method does not measure force. The meaningfulness of the method is also impaired by the following characteristics ... 

In another tack test, a steel ball of specified diameter is rolled down a grooved incline onto a conditioned surface area of pressure sensitive adhesive (ASTM D 3121, PSTC-6). The length of travel before it stops is the rolling ball tack (Fig. 2d) reported in millimeters. It is relatively inexpensive and simple to set up. Similar test variables to the probe tack test apply. 

Fig. 2. Tack tests and results, (a) Probe tack, (b) Probe tack vs. temperature for a natural rubber PSA. (c) Loop tack, (d) Rolling ball.

PSA Formulation and Properties. The formulations used in this study for the Hycar 2103-Prepolymer C and Hycar 2106-Prepolymer C PSA contain OH/NCO ratios of 1.7 and 1.3, respectively. Dibutyltin dilaurate catalyst is used at a 0.2 wt.% level based on the total adhesive solids. PSA samples are made from an 80% solids solution (by wt.) with a dry solvent system (27/73 by wt. of ethyl acetate-toluene) and cured at 150°C for 45 seconds. The samples are then evaluated by running 180° peel, static shear, rolling ball tack, and vinyl film shrinkage tests. 

These adhesive systems give an excellent combination of static shear (at both room temperature and 70°C) and rolling ball tack along with excellent vinyl film shrinkage resistance. The results of these tests are summarized in Table III. 

Figure V demonstrates the effect of adhesive dry coating weight on 180° peel strength and rolling ball tack with OH/NCO ratios of 1.7 and 1.3 for Hycar 2103 and Hycar 2106, respectively. Static shear tests run both at room temperature and 70°C show no creep for both systems throughout the thickness range tested.

Figure 4 Rolling ball tack testing (a) douglas (b) PSTC (c) dow. 

The classic test for tack of a pressure-sensitive adhesive film is the rolling ball tack test. Here a ball is rolled down an inclined plane onto a film of the adhesive. The length the ball travels across the film before stopping is a measure of the tack of the film. This test gives a good indication of tack with elastomer adhesives but is unreliable with water-based systems. 

ASTM D3121 -94 (1999) Standard test method for tack of pressure-sensitive adhesives by rolling ball. 

Pressure Sensitive Tadc of Adhesives Using an Inverted Probe Machine, Test for (D 2979) Tack of Pressure-Sensitive Adhesives by Rolling Ball, Tbst for [Pg.790]

Another ASTM standard method, rolling ball tack (12), involves placing a piece of tape, adhesive side up, at the base of an inclined surface. A steel ball is allowed to roll down the incline from a fixed height, and the distance that the ball travels across the adhesive surface of the tape is taken as a tack value. Longer distances of travel indicate that the tape is less tacky. Other tests involving drums, rollers, or loops of tape have also been used, but are not as common. 

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