In the application of crosslinking peroxides, it is very important to know the safe processing and the typical crosslink temperature.
The safe processing temperature is defined as the temperature at which the scorch time ts2 is longer than 20 minutes. The typical crosslink temperature is defined as the temperature at which optimal cure (t90) is reached within about 12 minutes. This means that within this time, 90% of the total possible cross-links in the compound are formed.
Scorch and optimal cure times have been determined at various temperatures. The results are presented in the table below. From the values, the safe processing and typical crosslink temperatures are extracted.
| |
Scorch time (ts2) and optimal cure times (t90) in minutes at various temperatures (°C) * |
| |
|
70 |
80 |
90 |
100 |
110 |
120 |
130 |
140 |
150 |
160 |
170 |
180 |
190 |
200 |
| Trigonox 145 |
ts2
t90 |
|
|
|
|
|
|
|
43
|
14
|
|
63 |
22 |
8 |
4 |
| Trigonox B |
ts2
t90 |
|
|
|
|
|
|
|
54
|
18
|
86 |
34 |
12 |
5 |
2 |
| Trigonox 101 |
ts2
t90 |
|
|
|
|
|
|
45
|
15
|
|
60 |
24 |
8 |
3 |
|
| Trigonox T |
ts2
t90 |
|
|
|
|
|
|
57
|
19
|
|
46 |
19 |
6 |
3 |
|
| Perkadox 14 |
ts2
t90 |
|
|
|
|
|
|
58
|
19
|
|
46 |
22 |
7 |
3 |
|
| Perkadox BC |
ts2
t90 |
|
|
|
|
|
77
|
24
|
|
65 |
25 |
10 |
4 |
|
|
| Trigonox 17 |
ts2
t90 |
|
|
|
|
|
35
|
12
|
72 |
30 |
11 |
5 |
|
|
|
| Trigonox 29 |
ts2
t90 |
|
|
|
|
35
|
11
|
50 |
16 |
7 |
|
|
|
|
|
| Trigonox C |
ts2
t90 |
|
|
29
|
20
|
11
|
61 |
30 |
12 |
5 |
|
|
|
|
|
| Perkadox PM |
ts2
t90 |
|
|
|
6
21 |
2
9 |
1
4 |
|
|
|
|
|
|
|
|
| Perkadox L |
ts2
t90 |
|
42
|
14
72 |
5
22 |
7 |
|
|
|
|
|
|
|
|
|
| Perkadox PD |
ts2
t90 |
47
|
12
|
2
10 |
4 |
2 |
|
|
|
|
|
|
|
|
|
* The data were determined in a rheometer with a moving die, according to ISO 6502:1991
Remark: Scorch data were determined in the following test compound: 10 mmol of peroxide in 100 g EPDM, 50 g carbon black N-762 and 10 g paraffinic oil. For the difunctional peroxide Perkadox 14, only 5 mmol and for Trigonox C 20 mmol was added. Exceptions to this procedure are the Perkadox L, Perkadox PD and Perkadox PM formulations; these were tested by using 2 mmol of peroxide in 100 g of silicone rubber.