Pilcure MOR is a delayed action sulphenamide accelerator for NR, NR-BR blends, NR-SBR blends and other highly unsaturated synthetic rubber based compounds reinforced with fine particle size furnace blacks prone to excessive heat generation during processing operations. Pilcure MOR pellets exhibit good storage stability and disperse easily in rubber compounds due to comparatively lower melting range of Pilcure MOR.
Normal dosages of Zinc oxide and Stearic acid are necessary for cure activation of compounds based on Pilcure MOR. Pilcure MOR is used at 0.5-1.0 phr dosage for conventional cure systems, at 1.5 to 2.0 phr dosage for Semi-EV cures and at 3.0 and above for low sulphur EV cures.
Pilcure MOR is very active above 140°C and offers longer scorch delay; particularly during high temperature processing operations (e.g.extrusion/ calendaring, etc.) as compared to Pilcure CBS or Pilcure NS for tyre treads or similar high performance rubber compounds.
The rubber compounds based on Pilcure MOR exhibit excellent shelf life and retention of cure activity on prolonged storage as compared to other sulphenamide accelerators. At curing temperatures Pilcure MOR exhibits delayed on- set of cure along with faster cure rate and a very good plateau effect. The crosslink density obtained by using Pilcure MOR is approximately 6-8% lower than Pilcure CBS and 12 to 15% lower than Pilcure NS when compared at equal dosages of these sulphenamide class accelerators. Progressive increase in Pilcure MOR dosage, like other sulphenamide accelerators, shows improvements in scorch delay, cure rate and state of cure. The vulcanizates based on Pilcure MOR exhibit higher modulus, excellent elastic properties under dynamic conditions and lower heat buildup under dynamic stress. Semi-EV cure systems based on Pilcure MOR offer improved heat and ageing resistance.
Pilcure MOR is usually incorporated in the rubber compounds at the end of the mixing cycle. In case Pilcure MOR is to be added at a later stage it is sufficient to ensure that the rubber compound is warmed to 80-85°C for achieving excellent dispersion and dissolution of Pilcure MOR.
Pilcure MOR is a sulphenamide accelerator based on secondary amine (Morpholine) and hence is extremely sensitive to booster accelerators like DPG, DOTG, TMTM, and ZDC as as well as pre vulcanization inhibitor Pilgard PVI (CTP). Thus, when booster accelerators are required for further activation or Pilgard PVI is required for further scorch delay; very small dosages can produce desired response. Pilcure MBT (used in small dosages) also activates the rate of cure; however, thiuram accelerators TMTM / TMTD and dithiocarbamates are generally preferred as booster accelerators for achieving desired vulcanizate properties.
Like other sulphenamide accelerators, Pilcure MOR also decomposes rapidly in the presence of hot steam and can be used for the manufacture of open steam cured products requiring faster onset of cure; however, similar advantage is not offered for hot air cured products in the absence of strong booster accelerators. Pilcure MOR is an excellent accelerator for EPDM cures where long scorch delay and faster cure rate is desired. A cure system of Pilcure MOR 3.5 phr and Sulphur 1.5 phr may be used for curing products like dock fenders where long scorch delay, excellent stock shelf life and faster cures are needed.
Pilcure MOR is the most effective retarder for thiuram based EV-cures. Incorporation of Pilcure MOR reduces the blooming tendency of the thiuram cured vulcanizates and contributes to improvements in the state cure if sulphur is incorporated at small dosage.
Pilcure MOR based vulcanizates have a typical amine odor & bitter taste and hence Pilcure MOR is generally avoided for the manufacture of rubber goods intended for repeated contact with food / drugs.
Pilcure MOR alone or in combination with small quantities of booster accelerator is widely used in NR, SBR, NR-BR/SBR blends, NBR and other synthetic rubber based compounds used for the manufacture of auto tyres, tyre retreading materials, conveyor and power transmission beltings, rubber goods with thick cross sections, intricately shaped rubber goods, rubber footwear, injection molded goods, cables and other miscellaneous molded and extruded rubber products.
Typical dosage of Pilcure MOR based accelerator systems are given below:
Product
|
Rubber
|
Accelerators / Sulphur, phr.
|
MBS
|
MBTS
|
TMTD
|
PVI
(CTP)
|
S
|
Truck & Bus Tyres - Tread
Sidewall
Casing
|
NR-BR
NR-BR
NR-SBR
|
1.1-1.2
0.9-1.0
0.8-1.2
|
-
-
-
|
-
-
-
|
0.15-0.20
0.15-0.20
0.15-0.20
|
1.5-1.6*
1.8-2.0*
2.0-2.4*
|
Conveyor Belt Cover
General Purpose
Heat Resistant
|
NR
NR-SBR
|
0.6-0.8
1.5
|
0.1-0.3
-
|
-
0.5
|
0.10-0.20
0.15-0.20
|
2.3-2.5
0.5-0.7
|
V Belts Base
Cushion
Friction
|
NR
NR
NR
|
0.5
0.5
0.6
|
0.2
0.2
0.2
|
-
-
-
|
0.10-0.20
0.15-0.20
0.15-0.20
|
3.0
2.4
2.75
|
Retreads Hot Cure
Pre Cured
|
NR
NR-BR
NR-BR
|
0.5
0.8
1.0
|
-
-
0.2
|
-
-
-
|
0.15
0.15
0.10
|
2.4*
2.0*
1.6
|
Footwear DV Soles
Molded Soles & Heels
|
NR-SBR
NR-SBR
|
0.8
0.8
|
0.4
-
|
0.1
0.2
|
0.10
0.10
|
2.0
2.2
|
Injection Moldings
|
NR
|
0.7
|
-
|
-
|
0.25
|
2.4
|
Molded & Extruded Goods
|
NR
NR-SeEV
NR-EV
SBR
SBR-SeEV
SBR-EV
NBR
NBR-SeEV
NBR-EV
|
0.7-0.8
1.5-2.0
2.5-3.0
1.0-1.2
1.5-2.5
1.5
1.0-1.2
1.5-1.2
2.0
|
0.1
-
-
0.2
-
-
0.2
-
-
|
0.0-0.2
0.3-0.5
0.5-0.6
0.1-0.2
0.5
2.5-3.5
0.1-0.2
0.5-0.7
3.0-4.0
|
0.10-0.20
0.10-0.20
-
-
-
-
-
-
-
|
2.2-2.5
0.8-1.0
0.3-0.5
2.0-2.2
0.7-1.0
0.3-0.5
1.5
0.75
0.3
|
Note: * Insoluble Sulphur (100% active content basis)
|