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Semi-ultra-accelerator |
Behaviour in Vulcanization
The main function of NAFTOCIT ZMBT is as secondary accelerator in sulphur cured latex; in dry rubber it is a moderately fast curing primary accelerator. NAFTOCIT ZMBT is an accelerator whose effectiveness lies between NAFTOCIT MBT and NAFTOCIT MBTS. It becomes active at temperatures above 120 °C.
NAFTOCIT ZMBT is activated by thiurams, dithiocarbamates, guanidines, amine accelerators and other basic substances. When used in solid rubber compounds NAFTOCIT ZMBT requires stearic acid (NAFTOZIN) and zine oxides in normal dosage.
A better compression set resistance in latex foam can be achieved by using NAFTOCIT ZMBT; furthermore in latex films a higher modulus is obtained than with dithiocarbamates alone.
Vulcanizates accelerated by NAFTOCIT ZMBT show very good ageing properties. NAFTOCIT ZMBT does not bloom on vulcanizates.
NAFTOCIT ZMBT does not affect the inherent colour of pure white articles. Exposures of the articies to light causes gradual and slight yellowing. All vulcanizates produced with mercapto accelerators have a bitter taste.
Typical fields of application
Light coloured latex articies such as carpet backings, foam rubber, bath mats, soft rubber products.
DosageAs a general guide, equal parts of NAFTOCIT ZMBT and NAFTOCIT Di 7 give good results.
Good general purpose systems are the following:
NR latex: 0.5 phr (by wt.) NAFTOCIT ZMBT, 0.5 phr (by wt.) NAFTOCIT Di 7, 1.0 phr (by wt.) sulphur
SBR: 1.0 phr (by wt.) NAFTOCIT ZMBT, 1.0 phr (by wt.) NAFTOCIT Di 7, 2.0 phr (by wt.) sulphur
Food contact applications
BGA: Empf. XXI, Cat. 3
FDA: Regulated in CFR 21, § 177.2600.
Shelf life
At least 2 years when avoiding extremely high temperatures and humidity.
Standard packing
Multi-ply paper bags with PE-lining, 20 kg.
Product information
| NAFTOCIT ZMBT | ||
| Product form | powder | |
| Product Specification | ||
| Zinc content (%) | 16 - 18 | |
| Free MBT (%) | 11 - 16 | |
| Sieve residue 63 micro (%) max. | 0.5 | |
| Evaporation loss (105°C) (%) max. | 0.3 | |
| Colour | yellowish powder | |
| Odour | non pungent | |
| Appearance | free of hard parts and conglomerations | |
| Typical Properties | ||
| Specific gravity 20°C (g/cm3) | approx. 1.7 |
As at: January 1998