01 Thickener
thickener：After being dissolved or dispersed in water, it can increase the viscosity of the liquid and maintain a relatively stable hydrophilic polymer compound in the system. The molecular structure contains many hydrophilic groups, such as -0H, -NH2, -C00H, -COO, etc., which can hydrate with water molecules to form a high-viscosity macromolecular solution. Thickeners play an important role in cosmetics , with thickening, emulsifying, suspending, stabilizing and other functions.
02 Thickener action principle
Since the functional groups on the polymer chain are generally not single, the thickening mechanism is usually that one thickener has several thickening mechanisms.
Chain winding thickening：After the polymer is put into the solvent, the polymer chains are curled and entangled with each other. At this time, the viscosity of the solution increases. After neutralization with alkali or organic amine, the negative charge has a strong water solubility, which makes the polymer chain easier to expand, thereby achieving an increase in viscosity. .
Covalently cross-linked thickening：Covalent crosslinking is the periodic embedding of bifunctional monomers that can react with two polymer chains, linking the two polymers together, significantly changing the properties of the polymer, and having a certain suspension ability after being dissolved in water.
Association thickening：It is a kind of hydrophobic water-soluble polymer, which has the characteristics of a type of surfactant. The concentration of the polymer in water increases the association between molecules, and interacts with the hydrophobic group of the polymer in the presence of the surfactant, thus forming a surface active Mixed micelles of agent and polymer hydrophobic groups, thus increasing the solution viscosity.
03Classification of thickeners
According to water solubility, it can be divided into: water-soluble thickener and micropowder thickener. According to the thickener source can be divided into: natural thickener, synthetic thickener. According to the application, it can be divided into: water-based thickener, oil-based thickener, acidic thickener, alkaline thickener.
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Classification |
category |
raw material name |
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water soluble thickener |
Organic Natural Thickener |
Hyaluronic Acid, Polyglutamic Acid, Xanthan Gum, Starch, Guar Gum, Agar, Sclerotinia Gum, Sodium Alginate, Acacia Gum, Crumpled Carrageen Powder, Gellan Gum. |
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Organic semi-synthetic thickener |
Sodium Carboxymethyl Cellulose, Propylene Glycol Alginate, Hydroxyethyl Cellulose, Sodium Carboxymethyl Starch, Hydroxypropyl Starch Ether, Sodium Starch Phosphate, Acetyl Distarch Phosphate, Phosphorylated Distarch Phosphate, Hydroxylated Distarch Phosphate Propyl Distarch Phosphate |
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Organic Synthetic Thickener |
Carbopol, polyethylene glycol, polyvinyl alcohol |
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micronized thickener |
Inorganic Micropowder Thickener |
Magnesium aluminum silicate, silica, bentonite |
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Modified Inorganic Micropowder Thickener |
Modified fumed silica, steara ammonium chloride bentonite |
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Organic Micro Thickener |
microcrystalline cellulose |
04Common thickeners
1. Natural water-soluble thickener
starch：Gel can be formed in hot water, hydrolyzed by enzymes first into dextrin, then into maltose, and finally fully hydrolyzed into glucose. In cosmetics, it can be used as a part of powder raw materials in cosmetic powder products and adhesives in rouge. and thickeners.
xanthan gum：It is easily soluble in cold water and hot water, has ion resistance, and has pseudoplasticity. The viscosity is reduced but recoverable under shearing. It is often used as a thickener in facial masks, essences, toners and other water agents. The skin feels smooth and avoids seasoning. Ammonium preservatives are used together.
Sclerotin：100% natural gel, the solution of scleroglucan has special stability at high temperature, has good applicability in a wide range of pH values, and has great tolerance for various electrolytes in the solution. It has a high degree of pseudoplasticity, and the viscosity of the solution does not change much with the rise and fall of temperature. It has a certain moisturizing effect and good skin feel, and is often used in facial masks and essences.
Guar Gum：It is completely soluble in cold and hot water, but insoluble in oils, greases, hydrocarbons, ketones and esters. It can be dispersed in hot or cold water to form viscous liquid, the viscosity of 1% aqueous solution is 3~5Pa·s, and the solution is generally impermeable.
sodium alginate：When pH=6-9, the viscosity is stable, and alginic acid can form colloidal precipitation with calcium ions, and alginic acid gel can be precipitated in acidic environment.
carrageenan：Carrageenan has good ion resistance and is not as susceptible to enzymatic degradation as cellulose derivatives.
2. Semi-synthetic water-soluble thickener
Methylcellulose：MC, water swells into a clear or slightly turbid colloidal solution. To dissolve methylcellulose, first disperse it in a certain amount of water when it is lower than the gel temperature, and then add cold water.
Hydroxypropylmethylcellulose：HPMC is a non-ionic thickener, which swells into a clear or slightly turbid colloidal solution in cold water. It has a good foam-increasing and stabilizing effect in the liquid washing system, improves the consistency of the system, and has a synergistic effect with cationic conditioners, effectively improving Wet combing performance, alkali can speed up its dissolution rate, and slightly increase the viscosity, hydroxypropyl methylcellulose is stable to general salts, but when the concentration of salt solution is high, the viscosity of hydroxypropyl methylcellulose solution will decrease tendency to increase.
Sodium carboxymethyl starch：CMC-Na, when the degree of substitution is greater than 0.5, is easily soluble in water to form a transparent colloid; CMC with a degree of substitution lower than 0.5 is insoluble in water, but can be dissolved in alkaline aqueous solution. CMC often exists in the form of multi-molecular aggregates in water, and the viscosity very high. As the temperature increases, the viscosity decreases. When the pH is 5-9, the viscosity of the solution is stable; when the pH is less than 3, hydrolysis occurs while precipitation occurs; when the pH is greater than 10, the viscosity decreases slightly. The viscosity of CMC solution will also decrease under the action of microorganisms. The introduction of calcium ions into the CMC aqueous solution will cause turbidity, and the addition of high-valent metal ions such as Fe3+ and Al3+ can cause CMC to precipitate or form a gel. Generally, the paste is relatively rough.
Hydroxyethyl cellulose：HEC, thickener, suspending agent. It can provide good rheology, film-forming and moisturizing properties. High stability, relatively sticky skin feeling, very good ion resistance, it is generally recommended to disperse in cold water and then heat and stir to dissolve homogeneously.
PEG-120 Methyl Glucose Dioleate：It is specially used as a thickener for shampoo, shower gel, facial cleanser, hand sanitizer, children’s washing products, and tear-free shampoo. It is more effective for some surfactants that are difficult to thicken, and PEG-120 methyl glucose dioleate is not irritating to the eyes. It is ideal for baby shampoo and cleansing products. It is used in shampoos, facial cleansers, The AOS, AES sodium salt, sulfosuccinate salt and amphoteric surfactants used in the shower gel have good compounding and thickening effects,