Neutralisation of liquid handwash

Formulating

Neutralisation of liquid handwash

Posted by MurtazaHakim on March 12, 2019 at 10:31 am

Greetings to all the forum members.
The following are the ingredients of the product we made. For a batch of 2500 litres we used the following:

1.LABSA 96% - 158.3 kg
2.Caustic Soda Flakes - 26.6 kg
3.SLES 70% - 208 kg
4.Iodized salt - 53 kg
5.Water - to the balance

The pH of the resulting product is 14. How can I reduce the pH of this product now ? This product is intended to be sold as either handwash or dishwash liquid. The colorant is fading as well. What is the recommended pH for the aforementioned end uses of this product ?

Fekher replied 5 years, 8 months ago 6 Members · 8 Replies
8 Replies

Gunther

Member
March 12, 2019 at 7:54 pm

pH 14 means too much Sodium hydroxide was added.
LABSA carbon lengths may vary from supplier to supplier, even from batch to batch, so the NaOH amount needed to neutralize it varies a bit as well.

Calculate the NaOH amount needed to neutralize LABSA and substract 2%
then add the remaining 2% NaOH (in water solution) in small increments of 0.1% and check the pH level after each one.

pH 7 would be fine to make it a bit less harsh on the skin. I believe sulfonates can be lowered to pH 6 without degrading themselves.
Sulfonates are just too harsh for handwash. Some people even find SLES/SLS formulations too harsh for their hands.
MurtazaHakim

Member
March 13, 2019 at 9:35 am

The material safety data sheet of “Fairy” a dishwashing liquid from P&G states the pH of 9. What I reckon is that at pH of 7 the cleansing action will not be sufficient.
Amittal

Member
March 14, 2019 at 3:10 am

@MurtazaHakim you can add citric acid aprox 1.4 kg or more to make it neutral. Check ph if it’s not 7 den increase citric acid 100gm again check ph and so on.
But if the product ph decrease too much den again add caustic soda.
Aziz

Member
March 14, 2019 at 11:20 pm

MurtazaHakim said:

The material safety data sheet of “Fairy” a dishwashing liquid from P&G states the pH of 9. What I reckon is that at pH of 7 the cleansing action will not be sufficient.

Is it a hand wash formula or a dish wash formula ? You are warking with a so large quantity , have you no chemist ?
MurtazaHakim

Member
March 15, 2019 at 3:55 am

Unfortunately, I am working as the chemist. Actually l have no experience of surfactants, personal care and household care industry. My actual qualification is a bachelorette in Petrochemical Engineering.

Coming to your question Aziz, the formula is a multipurpose formula. The product is sold as both handwash and dishwash liquid. I know LABSA is quite harsh and is designated to be a hard surfaces cleaner, but due to financial constraints the company does not use ingredients like CMEA/CDEA,CAPB etc… which are expected to be used for making any moderate liquid handwash. Furthermore the colorants are food grade as well. There are no humectants, preservatives in the product.

Kindly share any economical formula for handwash which I can try and produce the product at a lower cost.
belassi

Member
March 15, 2019 at 4:45 am

You will absolutely have to include a proper preservative or the whole lot will go bad in a matter of weeks and possibly infect your customers. Food grade colours fade rapidly in natural light.
Aziz

Member
March 15, 2019 at 4:55 am

I am an organic chemist , making hand wash , dish wash , shower gel etc. Here I have to compete with the products of Liver and brands like Dettole , Savlon , Vim etc. People compare with these products .
1. I suffer same experience like you . Unfortunatly one batch of my dish wash was changing colour periodically , I tested pH exceed 12 . I find out the coz , I used tap water and this was the cause of pH and colour change .
2. In hand wash formulation you should not use NaOH and LABSA . Price diffrence with SLES is not so high . So use SLES , at least a small percent of CAPB to reduce stringy effect and surely small percent of glycerin or sorbitol .
3. If you are in a competative market , you have to make your formula thicker , to do this you can use pre hydrated Xanthane gum .

So an economy formula may like this
1. SLES
2. CAPB
3. EDTA
4.Citric Acid(to adjust pH )
5.Sodium benzoate (preservative)
6.Sorbitol
7.NaCl
8. Xenthene gum
9. Perfume
10. DM Water
If DM water is not possible , pass your water through 3 to 5 stage strainer or RO plant .
To make viscous without gum , solid percent of SLES , CAPB ,CDEA should be 13 to 15% .
If you have no headache about viscosity , you can reduce the percent of solid .
Do some reserch and make your own formula .
Fekher

Member
March 15, 2019 at 9:04 am

@MurtazaHakim for correction the best way i find that take for example 10 kg from your bad product then do correction with it for your case you need for sure acid to reduce ph as they said citric acid will be good choice then when you find the best quantity to add for correction , make your calculation to know adequat needed quantity for your batch.