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Thixotropic agent in water based formulas
Dear Formulators,
I manufacture Liquid Sindoor (Red colored liquid used by Indian Women after marriage to be applied on forehead).
I am wondering which thixotropic agent is better
A- Xanthan gum
B - CMC (Carboxy methyl cellulose)The formulation contains
Water - Qs
polyacrylate used as film former (neutralized by TEA) .
Anti suspending agent
Adhesive agent (PVPK 30)Note - This is not a rinse off application, The product will stay on the skin for the whole day.
Thanks in advance !
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5 Replies
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I’m not sure I understand the reason for the question. Why isn’t the polyacylate being used as the thixotropic agent?
But between xanthan gum and cellulose, both could work but I think you’ll find cellulose easier to work with -
Perry said:I’m not sure I understand the reason for the question. Why isn’t the polyacylate being used as the thixotropic agent?But between xanthan gum and cellulose, both could work but I think you’ll find cellulose easier to work withThe polyacrylate used in this formula is Dermacryl 79 of Nouryon. It imparts only film forming properties being of higher molecular weight acrylic copolymer. It imparts no thixotropic properties. Would you suggest Carbomer of any grade or any other agent.
The reason for using a thixotropic agent is that we need product with same consistency to withstand temperature variations, transport stress & longer shelf life.
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Xanthan will have the highest Yield Value for thixotropy of the two you mention but carbomer will outpace all of these and since you are already using Dermacryl 79 why not use carbomer and neutralize at same time as the other polyacrylate? - a win/win with matchy-matchy acrylic chemistry. (Again, like I been sayin’, xanthan gum is a substance abuse problem worldwide!)
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chemicalmatt said:Xanthan will have the highest Yield Value for thixotropy of the two you mention but carbomer will outpace all of these and since you are already using Dermacryl 79 why not use carbomer and neutralize at same time as the other polyacrylate? - a win/win with matchy-matchy acrylic chemistry. (Again, like I been sayin’, xanthan gum is a substance abuse problem worldwide!)
We will definitely try carbomer along with Dermacryl 79 & revert the result here soon. Our experience with Dermacryl 79 is that we need to use half wt/wt of TEA wherease when using carbomer the same TEA required is one fifth wt/wt of carbomer.
For example - When using Dermacryl 79 1 kg, we need 500gm of TEA to neutralize. However, while using 1kg of carbomer 980, we need 200 gm of TEA. How would we neutralize when both Dermacryl & carbomer are put in one aqueous solution?
In our experience, we can modulate viscosity of Xanthan Gum by adding or subtracting water, but carbomer once neutralized we find it difficult to modulate to desired viscosity.
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chemicalmatt said:Xanthan will have the highest Yield Value for thixotropy of the two you mention but carbomer will outpace all of these and since you are already using Dermacryl 79 why not use carbomer and neutralize at same time as the other polyacrylate? - a win/win with matchy-matchy acrylic chemistry. (Again, like I been sayin’, xanthan gum is a substance abuse problem worldwide!)
Thank you @chemicalmatt for your valuable suggestion.
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