Altogether 58 bases (pyridines, anilines, amines, guanidines
, amidines, phosphazenes) are included and around 120 independent [DELTA][pK.sub.ip] measurements (see Tables 6 and 7) were carried out.
The remaining phosphagens were enzymatically synthesized using the appropriate guanidine
acceptor and phosphagen kinase.
Most sulfenamides, thiazoles, guanidines
, thiurams and some dithiocarbamate accelerators are IMDG Class 9 environmentally hazardous materials and toxic to aquatic organisms.
Accelerators described include sulfenamides, guanidines
, thiurams, dithiocarbamates, thioureas and specialty curatives.
Compound 10, containing a high sulfur cure and a guanidine
accelerator, shows the guanidines
to be easily bondable, although it suggests that C8007/8210 is not the best choice.
Table 1 - classes of vulcanization accelerators and activators zClass Speed Amine-aldehyde Slow (condensation products) Guanidines
Medium Benzothiazoles Semi-fast Sulfenamides and sulfenimides Fast, delayed action Dithiophosphates and xanthates Fast Thiurams Very fast Dithiocarbamates Very fast zClass Acronyms Amine-aldehyde (condensation products) Guanidines
DPG, DOTG Benzothiazoles MBT, MBTS Sulfenamides and sulfenimides CBS, TBBS, MBS, DIBS, TBSI Dithiophosphates and xanthates ZBDP Thiurams TMTD, TMTM, TETD Dithiocarbamates ZMDC, ABDC
Thomas Swan & Co., Ltd., acquired the U.S.A.-based Pepton peptizer and guanidines
rubber chemicals products of Cytec Industries.
Table - 15 Product class Possible formation of suspect nitrosamines Sulfenamides (primary amines) No Sulfenamides (secondary amines) Yes Thiazoles No Guanidines
No Dithiocarbamates Yes Thiurams Yes Specialty amines No (in most cases) Dithiophosphates No Sulfur donors (secondary amines) Yes
as similar amine accelerators also serve to both activate and accelerate vulcanization.