Latex accelerator composition
View Patent ↗Accelerator composition for a rubber latex derived from a conjugated diene and optionally a vinyl aromatic comonomer including: (i) a diisopropyl xanthogen polysulphide (DIXP), (ii) an alkyldithiocarbamate wherein the alkyl chain contains from 5 to 20 carbon atoms, and (iii) diphenylguanidine (DPG), a curable aqueous synthetic rubber latex composition including said accelerator composition, a process for the water-based solvent-free manufacture of synthetic shaped synthetic elastomeric articles, prepared by using the accelerator composition.
1. An accelerator composition comprising:
(i) a curable aqueous synthetic rubber latex derived from the group consisting of a conjugated diene monomer; and a conjugated diene monomer with a vinyl aromatic comonomer; while further comprising:
(ii) a diisopropyl xanthogen polysulphide (DIXP);
(iii) an alkyldithiocarbamate, wherein the alkyl chain contains from 5 to 20 carbon atoms; and
(iv) diphenylguanidine (DPG);
wherein the composition is essentially free of zinc diethyldithiocarbamate (ZDEC) and zinc-2-mercaptobenzothiozole (ZMBT).
2. The accelerator composition of claim 1 , wherein as component (ii) diisonyl dithiocarbamate (ZDNC) is used.
3. The curable aqueous synthetic rubber latex composition of claim 1 additionally comprising:
(v) a vulcanizing agent; and
(vi) an activator.
4. The curable aqueous synthetic rubber latex composition of claim 3 , wherein the rubber latex is a poly(isoprene) rubber latex.
5. The curable aqueous synthetic rubber latex composition of claim 3 , wherein each of the ingredients (i), (ii) and (iii) of the accelerator composition are present in a concentration of from 0.25 to 1.00 phr, relative to the weight of synthetic rubber solid.
6. The curable aqueous synthetic rubber latex composition of claim 5 , wherein each of the ingredients (i), (ii) and (iii) of the accelerator composition are present in a concentration of from 0.25 to 0.80 phr, relative to the weight of the synthetic rubber solid.
7. A process for the water-based manufacture of synthetic elastomeric articles, comprising: (i) the preparation of a latex dispersion or emulsion that comprises a vulcanising agent, an activator and the accelerator composition of claim 1 ; (ii) maturation of the latex dispersion for a period of from 0.5 to 1.5 days; (iii) dipping a former in the shape of the article into the latex; and (iv) curing the latex present on the former.
8. Shaped synthetic elastomeric articles, prepared from the curable aqueous synthetic rubber latex composition of claim 3 .
9. Cured shaped synthetic elastomeric articles according to claim 8 , characterized by a tensile strength of at least 24 MPa (according to ASTM D-412) and an elongation at break of at least 750%.
10. Shaped synthetic elastomeric articles, prepared from the curable aqueous synthetic rubber latex composition of claim 4 .
11. Cured shaped synthetic elastomeric articles according to claim 10 , characterized by a tensile strength of at least 24 MPa (according to ASTM D-412) and an elongation at break of at least 750%.
12. Shaped synthetic elastomeric articles, prepared from the curable aqueous synthetic rubber latex composition of claim 5 .
13. Cured shaped synthetic elastomeric articles according to claim 12 , characterized by a tensile strength of at least 24 MPa (according to ASTM D-412) and an elongation at break of at least 750%.
14. Shaped synthetic elastomeric articles, prepared from the curable aqueous synthetic rubber latex composition of claim 6 .
15. Cured shaped synthetic elastomeric articles according to claim 14 , characterized by a tensile strength of at least 24 MPa (according to ASTM D-412) and an elongation at break of at least 750%.
16. Shaped synthetic elastomeric articles, prepared from the curable aqueous synthetic rubber latex composition of claim 7 .
17. Cured shaped synthetic elastomeric articles according to claim 16 , characterized by a tensile strength of at least 24 MPa (according to ASTM D-412) and an elongation at break of at least 750%.