Bill_Toge
Forum Replies Created
-
that depends on what’s in the formula
-
in my experience a coffee grinder works well on the lab scaleon an industrial scale an airtight high-speed mixer, e.g. a Robot Coupé Blixer or similar, should give good results
-
try hydroxypropyl cellulose
-
@Hirondelle21 a handy hint when selecting potential solvents is to get a numerical value for viscosity - the most effective solvents for perfumes are 10 cSt/cP or less (for comparison, water and alcohol are both around 1 cSt)
-
calcium carbonate is sold as chalk - if you can find food grade chalk, that’s your best betalso, diatomaceous earth tends to be very abrasive, personally I’d be very wary about using it in a toothpaste
-
surfactants thickened with salt are generally Newtonian, you could try formulating your product that way
-
instead of water, you could try using a low-viscosity non-alcoholic solvent instead; you’d be making your work a hell of a lot simpler
-
from your description, it sounds as if L1 is shear-thinning (viscous at rest, becomes less viscous under shear) and L2 is more Newtonian (same viscosity regardless of shear)
-
which carbomers did you try?some are much better suited to this task than others
-
@Lily7 or, more likely, they’re actually using HC / basic / non-anionic dyes and not declaring them on the label
-
try them and see; the fact they are generally used as co-surfactants doesn’t mean they can’t be used as principal surfactants
-
try PEG-40 hydrogenated castor oil or polysorbate 20 (pharmaceutical grade)
-
sodium ascorbyl 2-phosphate will oxidise, but at a much slower rate than vitamin C - whether or not this leads to visible discolouration depends on how much you have in the formulaif you keep your formula free of metal ions (i.e. used deionised water and a chelator) that will slow down the oxidation further
-
@ngarayeva001 try increasing the BHT to 0.5% and the tocopherol to 5%; there’s an awful lot of vitamin C equivalent in there, and 0.1% of either won’t last long against its insatiable lust for oxygen@Pharma sodium metabisulphite is permitted, albeit restricted, in Europe as a preservative at up to 0.59% (Annex V/9), and at higher levels in oxidative hair dyes, hair straighteners and self-tanning products (Annex III/99)
-
what’s the percentage of jojoba oil?
-
for thickening, try some combination of hydroxystearic acid / hydrogenated castor oil / trihydroxystearin, they’re reliable thickeners in this kind of solvent
-
how much BHT and tocopherol are you using?might be worth using a water-soluble antioxidant (e.g. sodium metabisulphite) as well
-
several major manufacturers (Merck, Eckart, BASF) sell iridescent pigments based on synthetic fluorphologopite instead of mica - chemically very similar to mica, but exceptionally pure, and with none of the ethical issues
-
chamomile flower CO2 extract is oil-soluble and imparts a green colour at very low levels, provided you don’t mind it being a slightly murky green, and imparting a smell of chamomile to the product
-
you don’t - salts of stearic acid are ionic, and HLB is only relevant to non-ionic emulsifiers
-
you need emulsifiers with a much lower HLB, e.g. Span 20 or polyglyceryl-4 oleate
-
@Belassi in his time they were using mercuric chloride!
-
@Pharma believe me, it doesn’t - once air is in toothpaste, it stays there forever
-
unless you want toothpaste like blancmange, a vacuum mixer is essential
-
sounds like non-uniform cooling; partially non-fluid products like
thin creams cool more quickly in some parts than others, and the heat
doesn’t dissipate at the same rate in all directions, so some parts
become more viscous than others, hence the clumpinga
little bit of a heat-resistant hydrocolloid like xanthan gum (say 0.1%)
can help by reducing the fluidity and making the structure of the liquid
less variable with temperature