The relation between compressibility and printing quality of foam adhesive tape (2)

Foam liner adhesive tape dynamic characteristics

The disadvantage of the CFD test is that the data comes from statistical tests.

On the press, the foam liner adhesive tape is continuously loaded and unloaded with each contact embossing with the substrate and the anilox roller. It is under this dynamic load that the foam pad adhesive tape Separating the plate from the press's vibration. It is our expectation to test the dynamic properties of the Foam Liner Adhesive Tape under this condition. Unfortunately, this kind of test is actually difficult to carry out. However, the rebound resilience of the foam liner can also be easily measured by the ball rebound test, whereby the dynamic characteristics of the foam liner adhesive tape can also be understood.

The test drops a ball of weight from above onto a foam cushion adhesive tape in a controlled manner to measure the rebound height of the ball.

Strongly resilient materials will be more resilient to falling balls than poorly resilient materials (reflecting more energy being absorbed). Table 2 summarizes the results of the resiliency test performed on a 20 mil foam pad adhesive tape and the relationship between the compressibility and the print quality of the foam pad adhesive tape.

Table 2 Compressibility and Resilience Index of 20 mil Foam Liner Adhesive Tapes from Three Different Manufacturers, as well as dot gain values ​​in different dot areas and ink density values ​​in the field version

Instant noodles liner tape CFD15% Ball rebound 5% dot 10% dot 30% dots Solid ink density
Polyurethane (A)

Softness 10psi 36 20% 32% 63% 1.43

Neutral 22psi 37 23% 36% 71% 1.56

Hard 34psi 28 36% 51% 74% 1.58

Polyethylene (B)

Soft 16psi 51 19% 31% 61% 1.42

Neutral 19psi 45 20% 35% 69% 1.55

Hardness 54psi 39 32% 47% 79% 1.59

Polyethylene (C)

Soft 17psi 53 20% 31% 60% 1.4

Hard 40psi 38 33% 51% 84% 1.53

Compared to open-cell polyurethane foam liner adhesive tapes, closed-cell polyethylene foam liner adhesive tapes have greater resiliency and use of soft foam liner adhesive tape The greater resiliency was even more pronounced with the soft foam liner adhesive tape (10-17 psi CFD at 15% compression). By comparing the compressibility and resiliency of two different types of foam liner adhesive tapes, the soft polyethylene foam liner adhesive tape is harder and has greater strength than the soft polyurethane foam liner adhesive tape. Resilience. However, the print quality they achieved was similar. The same result was obtained even when using a hard foam pad adhesive tape.

Foam liner paste adhesive tape imprint permission scope

The scope of imprint licensing refers to the ability to increase the embossing force without significantly affecting the dot gain. It can ensure that even if the imprinting force increases, the printing quality is guaranteed to remain consistent even when the plate or cylinder thickness changes. It is generally believed that thicker foam liner adhesive tapes will have a wider range of embossing tolerances, but in reality, 20 mil thick foam liner adhesive tapes are surprisingly different.

Compared with the rigid polyethylene foam liner adhesive tape C, the embossing tolerance range of the rigid polyethylene foam liner adhesive tape B increased by 24.3 psi. Figures 8 and 9 show how the cotton liner sticking tape will affect the dot gain when the print pressure increases when the slope of the CFD curve is different. When the compressive capacity of the foamed liner C in the 30% halftone area is increased by 2 mils, the dot gain is only 9 points, and the foamed adhesive tape B in the same case has a dot expansion of 24 points.

to sum up

Preliminary success has been achieved in predicting print quality by testing the physical properties of the Foam Liner Adhesive Tape. The test of compressive deformation CFD and ball fallback helps to increase the scientific classification of foam liner adhesive tape.
What should be remembered is:

(1) The CFD value of the 15% embossing deformation can be used for the classification of the corresponding printing quality of the 20 mil foam pad adhesive tape (see Table 1).

(2) Falling ball rebound test provides a simple and easy test method for the resilience of foam liner adhesive tape. The rebound property of foam liner adhesive tape can improve CFD at 15% compression. In order to improve the problem of dot expansion in printing.

(3) The compression allowable range of a 20 mil foam pad adhesive tape can be predicted from the slope of its CFD curve within the range of 10% to 25% compression.

Source: Bison