Liquid detergents are on the rise. They are easy to administer to surfaces and to stains before putting fabrics into the washing machine, and easy to administer into machine and manual dishes. But the liquids should not be too thin; it is easier to dose gels than water. And that is where thickeners come in.
Thickeners bring more advantages. They keep the liquid homogeneous; the non-dissolved ingredients are suspended in the thickened fluid. And not unimportant: thick fluids give a rich, concentrated impression, even if the liquid detergent holds max 5% active content, with or without thickener.
How thickeners work
Thickeners gel by combining with water molecules to form a 3-dimensional structure. The thickeners, often polymers with charges at its side chains, build hydrogen-bridges with the water molecules; without chemically bonding together, the thickener polymer chains stretch out through the water, extending bonding charges towards the surrounding water molecules. Bonds break and form when the gel is moved. This gives an elastic impression to the user.
Xanthangum, CMC (Carboxy Methyl Cellulose) and its sister HEC (Hydroxy Ethyl Cellulose) are three of the oldest thickeners. All three naturally derived products, they have the same cellulose backbone with polysaccharide (sugar-like) side groups. Apart from thickening, the cellulose ethers also have sequestering ability. A disadvantage is that these natural products work differently in different pH and in the presence of different electrolytes (salts). So they are not suitable for every single liquid formulation.
Thus, synthetic polymer thickeners were developed. Man-made polymers can be designed; their molecular weight and side chains can be chosen. This way, they can have optimum effect in the recipe. The advantages of such poly acrylates and poly urethanes are:
• Compatibility in very alkaline or acidic formulations
• Efficiency in formulations containing peroxides (bleaches)
• Dispersing power versus minerals and other ingredients in suspension
• Inhibition versus ions in precipitating conditions (this means the thickeners do not loose their gelling power when their charge is changed by other ions)
The Sirius Effect
Next to CMC Sirius can supply poly urethanes dissolved in water. Example of a Fabric Softener recipe:
Ingredients % by weight
Glydant (Preservative) 0.15
Poly urethane thickener 0.40
Ester Quat (the cationic) 7.00
Colour (1% solution) 0.05
Colour (5% solution) 0.07
To function well the finished product should have a pH of 2.5 – 3.5. This can vary according to the Ester Quat being used. If pH adjustment is necessary, Citric Acid solution is advised.
The mixing procedure:
1. Fill the mixing vessel with the water
2. Add Glydant and mix for approximately 5 minutes
3. Add Thickener and mix until homogeneous (20 – 30 mins.)
4. Add the Ester Quat and mix until homogeneous (20 – 30 mins.)
5. Add fragrance, colour and mix until homogeneous (10 – 15 mins.)
The entire procedure is executed at room temperature. It is not necessary to apply heat. It is important to incorporate the Thickener (Step 3) before initiating Step 4.
Mixing times will vary according to natures of particular components. Just make absolutely sure that at the end of each step the liquid is smooth and homogeneous.
For more information contact:
Telephone: +31 (0) 35 54 85898
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