Trouble with paint batches please help

[SamusAran723]

Any help or advise would be greatly appreciated on this matter. I work for an up and coming stucco/paint company as a quality control engineer. I'm fairly new and not used to this type of work and I'm having difficulty figuring out a solution to a perplexing problem surrounding our batches . We color test and white test our batches and a majority have been failing quality control. They are turning out too blue because of the RD3 titanium we mix in to make it white. When the batch is mixed to long or theres too much water it will always turn the batch to the blue side . I was wondering aside from the obvious solutions ( have production watch the associates like a hawk) if there is something chemical that can be done . I have tried adding the faintest amount of tint (axx exterior yellow) and it will subside some of the blue and then swing the batch to slight green . It also doesn't work for the color test ( shoot a colored formula to see how it compares to a master). It is still very blue due to the water content and RD3. If theres a powder that can tone down the RD3 and/ or absorb some of the water, I'd be willing to give it a shot .

[DrP]

Have you tried a different grade of whitener? Maybe talk to your TiO2 supplier and see if he has any advice.... if not then try some different grades of TiO2 from some different suppliers and see if the problem still persists. Get some samples in and mix some tests up in the lab to see if you can replicate the problem with other grades.

 

Also - I'm not sure how you can end up with 'too much water' in the mix - the guys should follow a strict batch mixing sheet or procedure which will require them to weigh out an exact amount of each of the raw materials going in. Adding extra water should only really effect the viscosity/flow/rheology of the system. If it is THAT sensitive to batch to batch fluctuation that a few kg extra water discolours the product, then the mix/formulation is not robust enough and you will need to do a little reformulation work as I suggested above - contact your TiO2 supplier and ask him for some advice or some samples of other grades.... if he can't help you then talk to someone else.... there are numerous suppliers of TiO2 that will bend over backwards to help you out and get you business I am sure.

 

I hope this helps - let us know how you get on.

 

Regards,

 

 

Dr P.

[DrP]

Err... how did you get on then? Let us know!.. ;-)