Peroxide masterbatch
Peroxide masterbatch comprising: —15-55 wt % of one or more organic peroxides, —15-45 wt % of at least one copolymer of (i) ethylene or propylene and (ii) 1-butene and/or 1-octene, and 13-45 wt % of at least two types of fillers—filler type 1 and filler type 2—each having a different BET surface area: (i) filler type 1 being present in the masterbatch in a concentration of 3-15 wt % and having a BET surface area of more than 100 m 2 /g; (ii) filler type 2 being present in the masterbatch in a concentration of 10-30 wt % and having a BET surface area of 100 m 2 /g or less.
1. Peroxide masterbatch comprising:
15-55 wt % of one or more organic peroxides,
15-45 wt % of at least one copolymer of (i) ethylene or propylene and (ii) 1-butene and/or 1-octene, and
13-45 wt % of at least two types of fillers—filler type 1 and filler type 2—each having a different BET surface area:
(i) filler type 1 being present in the masterbatch in a concentration of 3-15 wt % and having a BET surface area of more than 100 m 2 /g;
(ii) filler type 2 being present in the masterbatch in a concentration of 10-30 wt % and having a BET surface area of 100 m 2 /g or less.
2. Peroxide masterbatch according to claim 1 comprising 30-52 wt % of one or more peroxides.
3. Peroxide masterbatch according to claim 1 comprising an organic peroxide selected from the group consisting of dicumyl peroxide, di(tert-butylperoxyisopropyl)benzene, 1,1-di(tert-butylperoxy)-3,3,5-trimethylcyclohexane, butyl-4,4-di(tert-butylperoxy)valerate, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane and tert-butyl peroxy-3,5,5-trimethylhexanoate.
4. Peroxide masterbatch according to claim 1 wherein filler type 1 has a BET surface area of more than 150 m 2 /g.
5. Peroxide masterbatch according to claim 1 wherein filler type 1 is selected from carbon black, silica, and combinations thereof.
6. Peroxide masterbatch according to claim 1 wherein filler type 2 has a BET surface area below 10 m 2 /g.
7. Peroxide masterbatch according to claim 1 wherein filler type 2 is selected from calcium carbonate, barium sulphate, clay, and combinations thereof.
8. Process for the preparation of a peroxide masterbatch of claim 1 wherein the one or more organic peroxides, granules or pellets of the copolymer, and the at least two types of fillers are added to an extruder and extruded at a temperature in the range 50-95° C.
9. Process for crosslinking of an elastomer comprising the step of dispersing the peroxide masterbatch according to claim 1 in the elastomer to be crosslinked.
10. Process according to claim 9 wherein the elastomer is EPM or EPDM.