Latex accelerator composition
View Patent ↗Accelerator composition for a rubber latex derived from a conjugated diene and optionally a vinyl aromatic comonomer comprising: (i) a diethyl dithiocarbamate (like e.g. ZDEC), and (ii) diphenylguanidine (DPG), and substantially free of any thiazole derivative, a curable aqueous synthetic rubber latex composition comprising said accelerator composition, and a process for the water-based solvent-free manufacture of synthetic shaped synthetic elastomeric articles, prepared by using said accelerator composition.
1. An accelerator composition for a synthetic rubber latex, derived from a conjugated diene and optionally a vinyl aromatic comonomer, containing:
(i) a diethyldithiocarbamate, and
(ii) diphenylguanidine (DPG) and substantially free of any thiazole; and wherein the weight ratio (i)/(ii) of components (i) and (ii) is in the range of from 0.80 to 2.00.
2. The accelerator composition of claim 1 , wherein the weight ratio of components (i) and (ii) is in the range of from 0.80 to 1.50.
3. A curable aqueous synthetic rubber latex composition comprising a rubber latex, a vulcanising agent, an activator and as the only accelerator the composition of claim 1 .
4. A curable aqueous synthetic rubber latex composition comprising a rubber latex, a vulcanising agent, an activator and as the only accelerator the composition of claim 2 .
5. The curable aqueous synthetic rubber latex composition of claim 3 wherein the rubber latex is a poly(isoprene) rubber latex.
6. The curable aqueous synthetic rubber latex composition of claim 4 wherein the rubber latex is a poly(isoprene) rubber latex.
7. The curable aqueous synthetic rubber latex composition of claim 3 wherein the ingredient (i) is present in a concentration in the range of from 0.25 to 0.50 phr and the ingredient (ii) is present in a concentration in the range of from 0.20 to 0.50 phr, relative to the weight of synthetic rubber solid.
8. The curable aqueous synthetic rubber latex composition of claim 5 wherein the ingredient (i) is present in a concentration in the range of from 0.25 to 0.50 phr and the ingredient (ii) is present in a concentration in the range of from 0.20 to 0.50 phr, relative to the weight of synthetic rubber solid.
9. The curable aqueous synthetic rubber latex composition of claim 3 wherein the vulcanising agent concentration is in the range of from 0.50 to 0.90 wt %, relative to the weight of synthetic rubber solid.
10. The curable aqueous synthetic rubber latex composition of claim 5 wherein the vulcanising agent concentration is in the range of from 0.50 to 0.90 wt %, relative to the weight of synthetic rubber solid.
11. A process for the water-based manufacture of synthetic elastomeric articles, comprising:
(i) the preparation of a latex dispersion or emulsion comprising a vulcanising agent, a catalyst and the accelerator system of claim 1 ;
(ii) maturation of the latex dispersion for a period of from 0.5 to 1.5 days; dipping a former in the shape of the article into the latex; and
(iii) curing the latex present on the former.
12. Shaped synthetic elastomeric articles, prepared from the curable aqueous synthetic rubber latex compositions of claim 3 .
13. Shaped synthetic elastomeric articles, prepared from the curable aqueous synthetic rubber latex compositions of claim 5 .
14. Cured shaped synthetic elastomeric articles of claim 12 , characterized by a tensile strength of at least 18 MPa (according to ASTM D-412) and an elongation at break of at least 750%.
15. Cured shaped synthetic elastomeric articles of claim 13 , characterized by a tensile strength of at least 18 MPa (according to ASTM D-412) and an elongation at break of at least 750%.