The addition of rich gases to the stocktank crude oil according to original live oil composition resulted in more water-wetting characteristics, which indicates the influence of the light gaseous hydrocarbons in peptizing
and stabilizing the insolubles.
To minimize the problems mentioned above, some suppliers of processing promoters used for peptizing natural rubber and NR/SBR blends have developed diluted forms of these active chemical peptizers.
Table 3 - peptizing effect of "diluted" versus "pure" peptizers The conditions were as follows: BR laboratory internal mixer 40% fill factor 60 second mix time Rotor speed: 60 rpm Ingredients: SIR 20 natural rubber 0.3 phr "pure" peptizer 2.0 phr "diluted" peptizer Test procedure: Each batch passed once through a 1/4" open mill Each batch cut into 16 pieces Mooney viscosity at 100 [degrees] C determined on all pieces from center and edges of "sheeted" batch Test results (Mooney viscosity at 100 [degrees] C) Mixed 60 sec.
Table 4 - carbon black incorporation as a function of peptizing agent Recipe A B C D SIR 10 96.0 SBR 1516 4.0 Carbon black N-330 60.0 Naphtolen ZD 8.0 Vulkanox 4010 1.2 Vulkanox 4020 0.8 Vulkanox HS 1.0 Antilux 654 1.2 ZnO special 3.0 Vulkacit DOTG 0.2 Vulkacit TMTD 0.2 Vulkacit TBBS 1.0 Sulfur 2.0 Rhenogran CTP-80 0.3 Stearic acid 2.0 1.0 1.0 1.0 Renacit 7 -- 0.2 -- -- Aktiplast F -- -- 2.0 -- Aktiplast M -- -- -- 2.0 Carbon black incorporation 63.0 45.0 45.0 24.0 (seconds)
Product descriptions are provided on the web site for Struktol's entire product line, including activators, peptizers, antioxidants, plasticizers, coated sulfurs, plastic additives, coupling agents, specialty polymers, processing, dispersing and peptizing
agents, polyethylene waxes, fillers (non-black), rubber recycling, homogenizing agents/tackifiers and specialty chemicals.
When quinone diimines are added to natural rubber and carbon black in an internal mixer, and the mix is maintained at high temperatures for several minutes, the natural rubber experiences a softening or peptizing
The tetraethylthiuram disulfide (ethyl tuads) is the peptizing
agent, the octylated diphenyl amine (Agerite Stalite S) is an antidegradant, and the processing aid is a complex mixture (VanFre AP-2).
The only peptizing agents now important industrially are pentachlorothiophenol and its derivatives, dibenzamidodiphenyl disulphide and complex iron compounds.
As peptizing agents catalyze the oxidative chain splitting, it is obviously conceivable that the chemically accelerated depolymerization could affect the properties and durability of the vulcanizates.
The investigation reported here was carried out in order to study the chemically accelerated mastication of pentachlorothiophenol derivatives and boosters, how carbon black affects depolymerization, to compare the respective vulcanizate properties in general and aging in particular, and to consider the economics of mixing in the presence of peptizing agents.
The activator content of the commercial ingredient combinations account for 0.2-0.7% of the organic peptizing agent content and is lower by the factor 2-4 than that of the pure booster, Renacit 8 (B 300).
100 [degrees] C) on natural rubber of the commercially available peptizing agents based either on pentachlorothiophenol or on the pure booster Renacit 8 (B 300) were adjusted to similar levels; this is shown for various mastication times in figure 3.