Captax

Captax (Structure 15.21) is used to the extent of 1% with hevea rubber and accounts for the major part of the over 30,000 t of accelerators used annually in the United States. Other accelerators widely used include 2-mercaptobenzothiazole sulfenamide (Santocure Structure 15.22), used for the vulcanization of SBR dithiocarbamates and thiuram disulfides. Thiuram disulfide (Structure 15.23) is a member of a group called ultra-accelerators, which allow the curing of rubber at moderate temperatures and may be used in the absence of sulfur. 

Elastic-gel comp proplnt is prepd by milling oil-extended GR-S rubber (contg 100 parts rubber 30 ps oil) with 5 ps RPA No 3 (A 36.5% soln of xylyl mercaptan in a hydrocarbon solvent), 5 ps ZnO 1 part stearic acid. Then 300 ps oil is added, in small increments, followed by Captax 12, Tuads 6, diphenylguanidine 18, C black 20, sulfur 6 and finally AN (50-100 mesh) 1892 parts. The batch is mixed 60 mins, deaerated, cast and cured for 24 hrs at 220°F] DD)C.C.Rice W.B.Reynolds, USP 2993769 (1961) CA 55, 27891 (1961) [Comp proplnt prepd by mixing petroleum pitch with a polymer, a phase -stabilized Amm nitrate Amm dichromate. 

SYNS BENZOTHIAZOLE-2-THIONE 2(3H)-BENZOTHIAZOLETHIONE 2-BENZOTHIAZOLYL MERCAPTAN CAPTAX KAPTAX MBT MERCAPTOBENZOTHIAZOLE 2-MERCAPTO-BENZOTHIAZOLE 2-MERKAPTOBENZOTIAZOL 2-MERKAPTOBENZTHIAZOL NCI-C56519 PENNAC MBT POWDER ROKON ROTAX SULFADENE USAF GY-3 USAF XR-29 VULKACIT MERCAPTO... 

Captax/Rotax (purified form) R.T. Vanderbilt Company... 

The rising of the rate of chemical reactions between sulfur and rubber, acceleration of the vulcanization, and reduction of its temperature are accomplished using special accelerators. The use of a few accelerators may improve the vulcanization process because of their mutual activation. Two accelerators were used tetramethyl-thiuram-disulhde (thiuram-D) and CAPTAX . They act mutually and thus improve the vulcanization process and the resulting properties of RubCon. 

It has been found from experience that the maximal value of RubCon durability is obtained at the CAPTAX content of 0.05 mass%, and thiuram-D 0.35 mass%. The maximum durability against compression has been found at a maximum content of thiuram-D and moderate content of CAPTAX. 

The decrease of RubCon durability at a CAPTAX content of less than 0.05 mass% is caused by the violation of accelerators complex action and appearance of chemically free rubber. Content values of more than 0.05% causes excess CAPTAX and a related decrease in durability. The increase of product durability, when the content of thiuram-D approaches 0.45% is caused by gas deliverance and pore formation in the composite volume. 

The hypothesis of a positive influence of CAPTAX on durability because of the kinetic factor has been checked in the following experiment. 

The change of parameters of vulcanization kinetics found in the experiment allowed more order in the composite structure, a reduction of the number of dislocations, and consequently, improvement of the mechanical characteristics of RubCon. Let us note that the optimum content of the components in the system with the additive action of accelerators for rubber of the same kind is constant for PBN it is 7 parts thiuram-D per 1 part CAPTAX. 

Tests Rubber Sulfur Thiuram-D Captax Zinc Oxide Calcium Oxide... 

Captax . [R.T. Vanderbilt] 2-Mercapto-benzothiazole accelerator for natural and synthetic mbbers. 

CAPTAN CAPTENEET 26,538 or CAPTANE or CAPTAN-STREPTO-MYCIN 7.5-0.1 POTATO SEED PIECE PROTECTANT (133-06-2) see captan. CAPTAX ( 1 49-3 0-4) see mercaptobenzothiazole. 

CAPTAX (149-30-4) Combustible solid (autoignition temperature 1162°F/628°C). Dust or powder forms explosive mixture with air. Heat and/or contact with acids or acid fumes cause decomposition and formation of hydrogen sulfide and nitrogen oxide. Violent reaction with strong oxidizers. Flow or agitation of substance may generate electrostatic charges due to low conductivity. 

Mercaptobenzothiazole. 2f3H)-Benzothiazole-thione 2-beittothiatolethial MBT Captax Dermacid Mertax Thiotax. C7H5NS2 mol wt 167,25, C 50,27%, H 3,01%, N 8.38%, S 38,34%. Prepd industrially by reacting aniline, carbon disulfide, and sulfur at elevated press, and temps Kelly U.S, pat, 1,631,871. Purification by treat-... 

Captax -Tuads Blend. R.T. Vander-bUt] 2-Mercaptobenzothiazole/tetra-mediyldiiuram disulfide blend accel-erator for butyl rubbers. 

Equation (9.6) gives a somewhat simplistic schematic of the vulcanization reaction. On completion of the reaction, the pendant accelerator will cleave off (i.e., Captax) after generation of a crosslink. This accelerator residue, Captax, is an accelerator in its own right and continues to participate in further crosslinking as vulcanization continues. 

Captax . See 2-Mercaptobenzothiazole Captex 100. See Propylene glycol dicaprate Captex 200. See Propylene glycol dicaprylate/dicaprate Captex SOO", Captex 300EP. See Caprylic/capric triglyceride... 

Synonyms 2-benzothiazolethiol 2-mercaptobenzothiazole captax Rotax 2-benzathiazalethiol Dermacid MBT mercaptobenzothia-zole Mertax Nocceler M Thiotax 2(3H)-benzothiazolethione Pennac MBT Rokon sulfadene benzothiazolethiol benzothiazole-2-thiol... 

Sulfur/nitrogen compounds can also be effective inhibitors for copper and brass in dilute HNO3. Thiourea derivatives and p-thiocresol perform quite well. Shah and Trivedi found that sodium diethyl dithiocarbamate is effective on brass, and Patel et al. ° discovered the same for mercaptobenzothiazole (the Soviet inhibitor Captax) and various imidazoles, although benzimidazole (as opposed to its derivatives) is not very good at all. 

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