In accordance with VDA 230-206 (VDA, 2007), the sample was prepared and attached to a semicircle aluminum jig with a length of 50 mm, using SSP-04 of Zins-Ziegler. The dynamic friction coefficient at a sliding speed of 1–150 mm/s was measured at normal loads of 2 N and 5 N. 
According to the test results shown in Figure 9, the dynamic friction coefficient of flocking exhibited four characteristics. First, the average dynamic coefficient was decreased approximately 60% as the normal load was increased from 2 N to 5 N for both non-coated and coated surfaces. Second, regardless of the type of coating, when applied to the flocking surface, it resulted in a reduction in the friction coefficient by more than 70%, on average (2 g/m2 is the minimum amount for Hwaseung Chemical’s coating). Third, when the spraying amount of the coating solution was increased, the friction coefficient showed a tendency to decrease. Based on the sample applied with Hwaseung Chemical’s coating, when the coating amount was increased from 2 g/m2 to 5 g/m2, the average coefficient of friction decreased by approximately 30% from 0.47 to 0.33, at a normal load of 2 N. Fourth, when the coating was not applied, the friction coefficient decreased as the sliding speed increased in the range of 21–150 mm/s at a normal load of 2 N. Therefore, λ is positive (λ = 4.01 x 10–4) as shown in Figure 5(b). Considering that the typical glass operation speed is 130–180 mm/s, this value of λ may lead to a negative damping ratio ζ (Figure (9)), thereby lowering the dynamic stability and causing vibration, which can result in squeaking noise. In the other cases, the value of λ is negative and that of the damping ratio is positive.
