We wish to develop a white colour Sealant Tape from Butyl Rubber/ Chloro Butyl / Bromobutyl, Hydrocarbon Resin-C5, Calcium Carbonate & Talc, Paraffinic Oil, Silica, Polyisobutylene, Titanium Dioxide etc. This Sealant will be extruded on Silicone Coated Release Paper in bead size 15mm width x 5mm thickness.
We want to increase its physical properties at elevated temperature ie we want to minimize the loss of Mooney viscosity at elevated temperature(50 deg to 120 deg celcius).
Can we partial vulcanization our formulation by UV Curing system as under:
Weather we can go for this route ? If yes what will be the procedure for this. What wavelength(nm) of UV Rays will be suitable for continuous curing of Sealant Tape of Size 15mm width x 5mm thick on a Convener Belt.
Speaking from my experience with UV-curing synthetic polyisoprene rubber by using the thiol-ene reaction I think there are two fundamental problems with your approach:
1. TiO2 will drastically reduce the depth of penetration of the UV radiation
2. 5mm is probably too thick for UV curing, even if no TiO2 is used.
Aside from this, usually mercury UV lamps are used for curing. The conveyor belt should pass through an enclosed UV curing "oven" to make sure nobody is exposed to the UV radiation. The required number of lamps depends on the geometry of your product as well as on the speed of the conveyor belt, which must be UV-resistant, of course. The "oven" will also need extensive air cooling since the lamps produce a lot of heat. Overall the investment and maintenance costs for such a setup are very high compared to normal vulcanization.
If you want to increase physical properties you should use renforcing filler as vulcasile S (silicic acid) if white rubber color wanted or carbon black if black rubber wanted instead of Calcium carbonate and talk
Dear @jamal Babawati... Thanks for your reply. We want to increase its physical properties in uncured state. Final product is in uncured state only.
This product is a PSA and becomes very soft when used in 80-100 deg Celsius. We want this product to retain its hardness in uncured state at 80-100 deg Celsius. The Mooney viscosity of the product becomes very less. will Silicic acid can help us or can you suggest any other product for this application required
what's the degree of moony viscosity of butyl rubber and which temp.you tested?
what you mean PSA product?
We test our product at 80 deg Celsius and MV1+4 comes down to 12-13 we want this product to retain its MV at 80 deg Celsius upto 22 to 24.
PSA means pressure sensitive adhesive. This product is adhesive in nature its used to seal and have to remove at 70 deg Celsius. If the product loses its Mooney viscosity than it become very soft and can not be removed from the substrate.
Dear Johannes Albert Österreiche...thanks for your valuable inputs... can you help us to know which additives we have to add to make it active for uv curing .. I mean which photoinitiator and other additives are required to add to make it uv curable.. Can we do if we make it 3.1mm thick.
I think using phenol formaldehyde resin with your ingredient can be worked as a reinforcing agent and tackifier and curing agent as well, so I suggest to try with a different percentage.
Dear Jamal I have already tried with Phenol formaldehyde resin but i think there function/curing starts at 150 deg Celsius or above.
Can you suggest any accelerators or by combinations by which we can cure at 70 deg Celsius
As suggested in the linked article you could probably use trimethylolpropane tris(3-mercaptopropionate) or similar compounds (from Bruno Bock Thiochemicals) as a crosslinker and a radical photinitiator such as Irgacure TPO L from BASF.
However, the cited work uses polyisoprene rubber so I am not sure how well it will work with butyl rubber which usually only contains small amounts of isoprene.
http://www.sciencedirect.com/science/article/pii/S003238611400490X
Vulcanization systems for IIR according to literature
1.sulphur
2. Quinone dioxide with oxidizing agent like PbO2 or pb3O4
3.Or Try to use resoles with activators such as SnCL4or FeCl3
So try to do partial curing using the vulcanization system above
Dear Jamal Babawati How can We use sulphur curing system make work at 70-80 deg Celsius. Please help us in this..
I have tried with PQD with Pb02.... But it didnt work for me. It did little bit of curing but when i try to remove the extrusion bead from mold at 70 deg Celsius material becomes very soft and did not removed.
Same happened with Resoles with activators such as SnCL4or FeCl3.
you know IIR have a low degree of unsaturation which it came from isoprene monomer
so its vulcanization are very slow, using sulfur with accelerator could be work or pre-vulcanization can be carried out by mastication under heat in internal mixers at 150-175c for 5 minutes using methyl N-dinitrosoaniline,
Dear Jamal Babawati.. Sir can you help us to know any model formulation for Butyl Rubber or Helo Butyl Rubber based which can be cured at 70 to 80 Deg Celsius.
Dear Jamal Babawati
Sir can you help us to know any model formulation for Butyl Rubber or Helo Butyl Rubber based which can be cured at 70 to 80 Deg Celsius.
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