Home Cosmetic Science Talk Formulating Liquid dishwashing soap

  • Farrukh

    Member
    August 24, 2020 at 1:14 am

    Use caustic soda to make slurry

  • nelson

    Member
    August 24, 2020 at 8:40 pm

    can you share how ?
    1. dissolve caustic soda to water then slowly add labs

    can you share what percentage mix ? how many water, caustic soda and labs?

  • ozgirl

    Member
    August 24, 2020 at 10:20 pm
  • ketchito

    Member
    August 24, 2020 at 11:40 pm

    Hi Nelson. What you want for making a dish soap is not to make an acid slurry, but to neutralize your Linear alkyl benzene sulfonic acid (LABSA). LABSA is actually a poor detergent, so you need to neutralize it to get the real detergent, Linear alkyl benzene sulfonate. The amounts really depend on how much LABSA you’re gonna use in your formula. If it’s your only (anionic) surfactant, it sould be anywhere between 15-22% (it could also be a little bit less or a little bit more). You can check this Stepan bulletin to know how much Sodium hydroxide you’d need: https://www.stepan.com/content/dam/stepan-dot-com/webdam/website-product-documents/product-bulletins/surfactants/BIOSOFTS118.pdf. Soda ash is a good addition, since it’d help you stabilize the system…0.05-0.1 would do the trick, but then, you’d have to reduce a bit your Sodium hydroxide since the final pH will be very high.

  • Farrukh

    Member
    August 26, 2020 at 12:58 am

    nelson said:

    can you share how ?
    1. dissolve caustic soda to water then slowly add labs

    can you share what percentage mix ? how many water, caustic soda and labs?

    1 kg LABSA takes 180 grams caustic soda
    For this you take 180 grams caustic soda + 180 grams water to make lye 
    First dissolve LABSA IN WATER then caustic soda solution 

  • nelson

    Member
    August 30, 2020 at 1:42 am

    What do I formed when I combined soda ash + water + labsa

  • ketchito

    Member
    August 30, 2020 at 10:06 pm

    You’ll have a solution of Linear alkyl benzene sulfonate.

  • nelson

    Member
    September 1, 2020 at 9:54 pm

    Can I use this instead of acid slurry or Caustic soda + labsa?  Is it ok to have a dishwashing liquid With ph 6.5 , I noticed when add more soda ash to labsa , PH 7.3, results in a Little itch in my hand.
    when I used caustic soda + labsa - ph 8, but my hand is a Little dry and feels stripped of natural oil.

  • ketchito

    Member
    September 2, 2020 at 2:55 pm

    @nelson You can definitely use Linear alkyl benzene sulfonate instead of making it for your own. That is only if your formulation budget covers it. 

    If on the other hand, you choose to make the process yourself (mixing soda with labsa), you will want to have a high pH for your dishwash (around 8-9). This will not only ensures you converted all the labsa (or at least most of it) to labs, but also prevents pH shifting back to an acid pH over time due to an equilibrium. The oil stripping from your hand is normal, since you have more detergent as a product of the neutralization process.

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