Continue to Site

Eng-Tips is the largest engineering community on the Internet

Intelligent Work Forums for Engineering Professionals

  • Congratulations SDETERS on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

Synthetic SBR vulcanisation - help appreciated

Status
Not open for further replies.

phox86

Materials
Mar 3, 2020
1
Dear Forum,
I came here because I'm in partnership with House of children and education.
They have several educational programs for children and some of them contain a focus on rubber vulcanisation where children can try something of this process. It's part of technical, chemical and some other educational programs.

Till today was all of the experiments with rubber made of Revultex, which is prepared latex full of all accelerators and additives and it vulcanizes at room temperature.
So there is missing that parts of the process of mixing, high-temperature curing etc.

One of the sponsors gave House of children and education synthetic latex milk (it's likely SBR, about 200 litres)and insoluble sulphur (tens of kilograms). Sample of zinc oxide is also available (but I'm not willing to use it because of it's toxic for human and kids).

We have also available Granchem ZDEC/EG-75 and Granchem ZDBC/EG-75, which was recommended by an independent consultant.

We have also some experience with mixing and curing at industrial hot air oven (a bigger one, up to 350°C regulated).

1.
We tried to mix latex with sulphur and zinc oxide (don't remember exactly but I think that it was ration 3/100 of sulphur and 5/100 of zinc oxide by weight of latex) but there was a big sediment and nothing was looking like it want to dissolve (toluene wasn't working for dissolving because zinc oxide and insoluble sulphur are insoluble in toluene). We tried to put it in oven and mix it manually when the temperature was reaching 95°C. Nothing changed. There was still sediment of sulphur and zinc oxide and boiling latex was strongly bubbling. After drying there was uncured latex with sulphur and zinc oxide sediment.

2.
I also tried to make insoluble sulphur soluble by heating it at 200°C so it melted and after slow cooling, I tried to mix it with toluene and it was still not dissolving (mixing was with toluene and sulphur at room temperature).

3.
If the mixture will be correctly mixed, will it cure at high temperature (~160°C) into rubber?


My question is how can I dissolve insoluble sulphur and zinc oxide or other ingredients in SBR "milk". Can it be done with higher temperature mean with higher pressure when heating mixture up?
And if are there some next steps or processes I'm missing.


Thank you for all constructive critic and answers
BEST REGARDS
 
Replies continue below

Recommended for you

I think you need to dry out the latex first, you can't compound (mill and mix) the material with that much water in it...but I'm not sure what you get when SBR latex is dried to cake/crumb form. According to some websites, SBR latex is for waterproof coating of paper and textile products? If you can dry it to a crumb, then a small amount of petroleum oil will help in dispersing the vulcanizing agents in a dry mill.
 
Status
Not open for further replies.

Part and Inventory Search

Sponsor