SBR can be used in any cement based product which will improve durability water resistance, strength and flexiability, l use it extensively for over 20 years in all situations , with only positive results. Please tell how you consider it not to be a good idea, interesting to see how you justify your claims?.
The reason I have said "I am not sure adding SBR to anyone's levellers is a good idea" is because these products are developed by chemist over a long period of time by mixing up to sixteen different ingredients together testing them, adding ingredients, taking ingredients out, finding out that this ingredient does not work with that ingredient and changing ingredients again until after many many monthes of testing and field trials the cement based product has the correct balance and ratio of ingredients that all work together, so the produt will work and do has it was intended to. One of our products has 50 grams per 1,000kg batch, so upsetting the balance would not be to difficult. By adding SBR you also run the risk of altering the rheology of the product, which in a leveller can affect the flow rate and suface finish and with an adhesive will make it thicker and in some cases harder to serrate out. Adding SBR, or any other polymer or chemical without first checking the suitability with the manufacturer could easily upset the delicate balance of the ingredient and in the extreme, could cause an adverse reaction and a product failure. If you feel the need to add anything to a product to "improve it", would it not be better to choose a higher specification of product in the first place? If you are thinking of adding anything to cement base products it would be wise to check with the manufacturer first.