Page 87 - 《橡塑技术与装备》英文版2026年2期

TEST AND ANALYSIS

Calculate the average Shore hardness value for each 250 equipment used for FX-4 rubber recycling specify the
set of parameters, and plot a curve graph for the relationship requirements for roller spacing adjustment as follows: During
between roller spacing and the number of passes on the Shore normal spacing adjustment, the adjustment gap between the left
hardness of the rubber compound, as shown in figure 1. and right rollers should be limited within the range of 0.2~20.0
mm. The roller spacing setting for the thin passing process test
verification is set to a left and right roller adjustment gap of 0.2
mm, which means the roller spacing between the two rollers is
0.4 mm.
For the design of the thin-pass times indicator, within
the scope of process requirements, the thin-pass times were
set to 10, 13, and 15, respectively. The better the fluidity,
the worse the resistance, and the lower the Shore hardness
value. Therefore, after thin-pass, the sheet is subjected to
Shore hardness testing to characterize the fluidity of the
Figure 1 The influence of roller spacing and pass rubber compound. On this basis, after thin-pass, the surface
number on the Shore hardness of rubber compounds appearance of the blank is inspected to verify the impact of
thin-pass times on appearance quality. The verification results
As can be seen from Figure 1, with the increase of
are shown in table 3.
roller spacing, the Shore hardness of the rubber compound
Table 3 Test of thin-pass times
significantly increases; with the increase of pass times, the Number of thin- Shore hardness/degree of Appearance
Shore hardness first decreases and then increases, with pass 5 Test Number pass times/time rubber compound quality
1 10 56 qualified
< pass 7 < pass 3. Therefore, based on the above experimental 2 10 55 qualified
verification and analysis of the rubber compound softening 3 10 54 qualified
4 10 54 qualified
process, combined with the effect of the softening process on 5 10 48 qualified
reducing the hardness of the rubber compound and production 6 13 35 qualified
7 13 36 qualified
efficiency, the precise process parameters for the softening 8 13 37 qualified
process are determined as follows: roller spacing of 1.7 mm; 9 13 41 qualified
10 13 36 qualified
pass times of 5. 11 15 45 qualified
2.2 Blank thinning 12 15 43 qualified
qualified
13
49
15
The purpose of thin-passing the blank is to break the 14 15 46 qualified
15 15 43 qualified
macromolecular chains of the rubber compound through the
action of mechanical shear force, and to react with oxygen in
As can be seen from Table 3, the appearance quality of
the air to generate stable peroxide groups, thereby reducing the rubber compound is qualified under different thin-pass
the molecular weight. Referring to the requirements for thin-
times, proving that thin-pass times of 10, 13, and 15 have no
passing in the rubber product process of the Beijing Institute
impact on the appearance quality of the rubber compound. The
of Aeronautical Materials, it is recommended to lock the roller
relationship between thin-pass times and the Shore hardness of
spacing for thin-passing after the rubber compound becomes the rubber compound is plotted based on Table 3, as shown in
soft, with a thin-passing frequency of 10 to 15 times.
figure 2 below.
From a theoretical perspective, the smaller the roller
As can be seen from figure 2, with the increase in the
spacing during thin passing, the better the thin passing number of thin-pass cycles, the Shore hardness of the rubber
effect. However, considering factors related to the safe
compound first decreases and then increases, with thin-pass 13
use of equipment, the operating instructions for the XK-
cycles < thin-pass 15 cycles < thin-pass 10 cycles. Taking into

Vol.52，2026 ·43·