Formulating Hydroalcoholic Gels with Carbopol Technical ... - Lubrizol

More documents

Recommendations

Info

Neutralization of Carbopol Polymers in Hand Sanitizing Gels The key to formulating a hydroalcoholic gel with Carbopol polymers is choosing the correct neutralizing agent. Many neutralizing agents commonly used to neutralize Carbopol polymers in aqueous systems do not work in hydroalcoholic TDS-255 Formulating Hydroalcoholic Gels with Carbopol ® Polymers Page 4 of 6 systems. There are amine solubility limitations with high alcohol, low water containing systems. The solubility of the Carbopol polymer salt changes as the alcohol level is increased making the choice of neutralizing agents important. Different choices are provided as a guideline for the different alcohol type and level. Neutralizing Agent Versus Alcohol Level Maximum Alcohol Neutralization Ratio* Trade Name INCI Name Manufacturer Level Base/ Carbopol ® Polymer NaOH (18%) Sodium Hydroxide 20% 2.3/1.0 KOH (18%) Potassium Hydroxide 30% 2.7/1.0 TEA (99%) Triethanolamine 60% 1.5/1.0 Tris Amino (40%)** Tromethamine Angus / Dow 60% 3.3/1.0 AMP ® Ultra PC2000 Neutrol ® TE Aminomethyl Propanol Tetrahydroxypropyl Ethylenediamine Angus / Dow 80% 0.9/1.0 BASF 90% 2.3/1.0 Triisopropanolamine Triisopropanolamine Dow 90% 1.5/1.0 * Ratio values indicated above are for mucilages. For the 60% hydroalcoholic gel, divide the base ratio amount by 1.25 **NOTE: The 40% solution should be made from the Tris Amino crystal provided by the manufacturer. We do not recommend using the predispersed solution produced by the manufacturer due to its high impurity content Check your local regulations while selecting the appropriate neutralizing amine since there are often specific guidelines on the type of amine and impurity level in the amine for these types of formulations. Modification and Formula Enhancements for Hydroalcoholic Gels Common Formulation additives for Hand Sanitizing Gels Water soluble emollients Emollients Fragrance Carbopol ® polymers Rheology modifier Alcohol Disinfecting agent Specialty Silicones Botanical Actives
Formulation and Manufacturing Guidelines • Typical hand sanitizing gels contain less that 40 wt% water. Due to this formulation constraint, a common concern is how to effectively incorporate the Carbopol polymer. The general methods are outlined as follows, dependent on your choice of polymer: Direct Method: The direct method is the traditional method for dispersing Carbopol polymers. Carbopol Ultrez Polymers: This method is made easy with Carbopol Ultrez polymers since you simply sprinkle the polymer on the surface of the water. Allow the polymer to self wet and then begin agitation. The general procedure is described as follows: 1. Disperse the polymer into the water. Mix until smooth to insure a lump free dispersion is obtained. 2. Slowly add the alcohol with agitation and mix until homogeneous. 3. Add emollients if desired. Keep in mind that the order of addition may be critical to maintain product clarity. See “Adding Emollients” for further information. 4. Add the appropriate neutralizing agent with gentle sweeping agitation and mix until smooth. NOTE: If production equipment constraints require the water and alcohol to be combined before the dispersion of polymer, the Carbopol Ultrez polymers must be dispersed like a traditional polymer. The Carbopol Ultrez grade polymers will not self wet in a solution of water and alcohol. Carbopol Traditional Grade Polymers: These polymers can be dispersed in either the water or alcohol/water mixture. The polymer will swell more slowly when added to the alcohol/water mixture, so care must be taken to avoid the clumping and skinning of the polymer during the dispersion process. 1. Carefully disperse the polymer in the water or water/alcohol mixture with good agitation. High mixing speeds are generally preferred as it prevents agglomeration of the polymer on the surface of the water. Mix until the polymer is hydrated and the dispersion is smooth and free of lumps. TDS-255 Formulating Hydroalcoholic Gels with Carbopol ® Polymers Page 5 of 6 2. Add the alcohol with slow mixing to de-aerate the formulation if it was not included in Step 1. 3. Add emollients if desired. Keep in mind that the order of addition may be critical to maintain product clarity. See “Adding Emollients” for further information. 4. Add the appropriate neutralizing agent with gentle sweeping agitation and mix until smooth. • Water Source: Use deionized water. Carbopol polymers are sensitive to hard water ions, therefore, the clarity and viscosity may be negatively affected if regular tap water is used. If deionized water is unavailable, add a chelating agent such as tetrasodium EDTA at a level of about 0.05-0.10% (wt/wt%). • Adding Emollients: Several commercially available emollients can be added to the hand sanitizing gel to compensate for removal of oils on the hands by the alcohol. The following watersoluble emollients can be added directly to the water and polymer dispersion or just before neutralization. The use of these emollients from 0.3-0.5 wt% addition will not impact the final product clarity. Trade Name INCI Name Glucam E-20 Humectant Methyl Gluceth-20 Glucam E-10 Humectant Methyl Gluceth-10 SilSense Copolyol-1 Silicone PEG-33 and PEG-8 Dimethicone and PEG-14 SilSense SW-12 Silicone Ester Dimethicone PEG-7 Cocoate Hydramol PGPL Emollient PEG/PPG-8/3 Laurate Hydramol PGDS Emollient PEG-90 Diisostearate The Hydramol emollients can be added at use levels from 0.5-3.0 wt% and still maintain good clarity in the system. The use of other emollients may impact the final product clarity depending on the solubility profile of that particular emollient. Other emollients, such as isopropyl myristate, may need to be added to the alcohol and the water/polymer dispersion added to the alcohol/emollient phase to maintain final product clarity.
Page 1 and 2: TECHNICAL DATA SHEET TDS-255 Editio
Page 3: Clarity Results: %Transmittance at

Formulating Hydroalcoholic Gels with Carbopol Technical ... - Lubrizol

Create successful ePaper yourself

Delete template?

Save as template?