Bill_Toge
Forum Replies Created
-
it’s not so much bad as old-fashioned; there are other, less highly coloured/odoriferous materials that will do the same job just as well
-
you’ll have to learn how to shot web first
-
sodium stearate is your best bet for creating water-based sticks
-
between around 30 and 65% w/w it forms a crystalline phase which is completely rigid, and much harder to process than the lamellar phase it forms at 70% and above - this is why it’s sold as 70%, 28% or lowerwhether or not it needs preservatives depends on the pH of the dilution; dilutions without preservatives are around pH 12, and use their high alkalinity as preservationin my experience, industrial-scale dilution tends to be carried out using a specialist (and complex) Bran-Luebbe mixer like this one
-
also, chemicals are usually referred to by their trade names and common names rather than their IUPAC names, e.g. acetic acid and Hyamine 1622 rather than ethanoic acid and N-Benzyl-N,N-dimethyl-2-{2-[4-(2,4,4-trimethylpentan-2-yl)phenoxy]ethoxy}ethanaminium chloride
-
if you want to look up banned or restricted substances, the full lists are online:
-
from experience, I’ve found sorbitol in substantial quantities (5% or more) gives a cooling sensation, and a sweetener can mask bitter tastesmenthol and peppermint oil are both very bitter by nature; the first thing I’d try would be reducing them
-
also, if you’re using glyceryl stearate SE, that contains sodium stearate, which is anionic and therefore incompatible with the cetrimide
-
@Sibech the amendment allowing leave-on usage of MIT at up to 100 ppm was passed relatively recently (around 2005, if memory serves)before that, MIT was only permitted for use in rinse-off products, as a mixture with MCIT, at up to 15 ppm, so the current limit has just reverted to one which has historically been proven to be safe
-
as these are industrial labs, they’ll be run very differently to academic labs, and the chances are you’ll have to learn a completely new way of workingthe best advice I can offer is just to pay attention, work conscientiously and document your work clearly
-
use different preservatives: they’re not stable above 40°C, and if it’s a hot-fill product, the sustained heat in the filling process will be enough to destroy them@Sibech 15 ppm is more than sufficient to pass a challenge test; European limits on preservatives, dyes etc. are very generous, provided that you’re using the right one for the job
-
there are grades of silica specifically sold for use in dental care - they are very fine indeed, and even the most abrasive grades don’t feel grainy
-
the problem is that those two emulsifiers are liquids at room temperature, so the emulsion interface is weak, leading to separation (unless you stabilise it some way, and physically prevent the continuous phase from flowing at rest) - try using emulsifiers that are solids or pastes at room temperature
-
phenoxyethanol works well up to about pH 121,2-diols (butylene, pentylene, caprylyl glycol etc.) are also pH independent
-
the only time DEA and its derivatives can form nitrosamines are when they’re combined with nitrosating agents, e.g. bronopol or sodium nitrite; the former is rarely used in cosmetics these days, and the latter is virtually unknown (it’s limited to food)in the late 80s, one of my former employers had shampoos with cocamide DEA and bronopol that would literally turn black over time due to nitrosamine formation and oxidation
-
well they’re all numbers followed by a % sign, so they’re definitely the genuine article
-
also carbomer gels become thinner as electrolyte concentration increases
-
with a few exceptions, I have almost never determined the exact percentages when reverse-engineering products - for the most part it’s been a matter of educated guesswork, and most of the time, that’s all that’s requiredalso if you have a mixture of essential oils, or vegetable/plant seed oils, you’ll have great difficulty identifying and characterising them by chemical analysis@Gunther in Europe the compositions declared on the Cosmetic Product Notification Portal are strictly confidential, only visible to the Responsible Person and poisons centres/regulatory authorities
-
the problem you’re facing is that carbomers and xanthan gum are anionic, and the ingredients typically used in conditoners are cationic, so they are fundamentally incompatibletry using a non-ionic rheology modifier, like locust bean gum or tara gum
-
like many other non-Newtonian liquids, toothpaste does not have a constant viscosity - the viscosity varies depending on the rate of shear applied to itthe cheapest equipment that can be used to make quantitative and meaningful measurements is a Brookfield RVT dial viscometer with a heliapath, or any fuctional equivalent
-
phosphoric acid works well at very low levels, is readily soluble in water, is available in food grade, and is one of the least harmful acids as far as dental health is concerned; citric acid acts as a chelator and does a lot more damage to the teeth than non-chelating acids doalso, if you’re using sodium benzoate as a preservative, you’ll have to get the pH below 5 for it to work
-
(1) assuming it’s O/W, as most conditioners are, none; oil into water is the most typical way these products are manufactured(3) on a large scale (100 kg upwards), a hemispherical reactor with a contra-rotating scrape-wall mixer and a shear mixer is the best piece of kit for the job
-
are you using surface-treated pigments?
-
as an example, one of the people who swore by these products was the company chairman himself, who was in his seventies, did a lot of manual work around the site and frequently had cracked/chapped skin on his hands; once he started using the aqueous cream regularly (which had no pharmaceutically active ingredients - any effect was entirely due to petrolatum and mineral oil) these problems went away completely
-
in my experience the Trading Standards Agency (the body responsible for enforcing the Cosmetics Regulation in the UK) only get involved with cosmetics if a product is found to have consistently short weights, someone is injured by a product, or there are microbially contaminated/flagrantly illegal products on the market; for the most part, they have much bigger fish to fryhaving worked at a factory which produced large volumes of aqueous creams and ointments of various hydrophobicities, which were used religiously by certain members of staff and their families, it is quite possible that the occlusive effect of the product was in itself enough to alleviate your baby’s eczema