Cosmetics refer to products applied to human body (skin, hair, nails, lips and teeth, etc.). ) By smearing, spraying, sprinkling water or other similar methods, it can achieve the purpose of cleaning, maintaining, beautifying, modifying and changing appearance, or correcting human body odor to keep it in good condition. At present, the development trend of cosmetics is therapeutic, functional and natural.
1 classification of surfactants
Surfactants can be classified in many ways. According to the source of surfactants, surfactants are usually divided into three categories: synthetic surfactants, natural surfactants and biosurfactants.
1. 1 synthetic surfactant
Synthetic surfactants refer to surfactants prepared from petroleum and natural gas through chemical synthesis. The differences in the properties of surfactants are mainly related to the types of hydrophilic groups besides the size and shape of hydrocarbon groups. Generally, according to the structure of hydrophilic groups, surfactants are divided into ionic and nonionic types according to whether hydrophilic groups are charged or not, among which ionic surfactants are divided into cationic surfactants, anion surfactant surfactants and amphoteric surfactants.
1.2 natural surfactant
The oil crisis in the 1970s had a great impact on the surfactant industry with oil as raw material, which caused people to think about a series of issues such as energy consumption, technological production process, ecology and the safety of petroleum products, thus triggering a major revolution in the production of surfactants with natural oil as raw material. Due to the application of new biotechnology, the development of oil separation and refining technology, and the improvement and increase of vegetable oil varieties, it is possible to obtain a large number of natural oils with low price and high purity. The successful development of a new antioxidant has solved the problem of natural oil spoilage and improved people's awareness of safety and environmental protection. The development of natural surfactants based on oil has attracted great attention. At present, palm oil and palm kernel oil are the most important natural oils.
1.3 biosurfactant
Biosurfactants refer to compounds with surfactant properties produced by bacteria, yeast and fungi. The production of surfactants by microorganisms is a new topic in the field of international bioengineering in the late 1970s. Using microorganisms to prepare biosurfactants can obtain many products that are difficult to synthesize by chemical methods, and new chemical groups are introduced into the structure, so the prepared products are easy to be completely degraded by organisms, non-toxic and ecologically safe. Biosurfactants can be divided into glycolipids, acyl peptides, phospholipids, fatty acids and polymer surfactants according to their hydrophilic groups.
2 the role of surfactants
Surfactant is a multifunctional fine chemical, which has many functions such as wetting, dispersing, emulsifying, solubilizing, foaming, defoaming, washing and decontamination.
When the liquid contacts the solid surface, the gas is repelled, and the original solid-gas interface disappears and is replaced by a solid-liquid interface. This phenomenon is called wetting. Generally speaking, wetting is a process in which one fluid is replaced by another fluid from the surface.
Generally, the process of dispersing particles or droplets and tiny forms of substances into another medium is called dispersion. The uniform and stable system obtained is called dispersion.
Emulsification is a process in which liquid is uniformly dispersed in another immiscible liquid medium in the form of tiny droplets or liquid crystals to form a heterogeneous dispersion system with considerable stability.
After the surfactant forms micelle in aqueous solution, it has the ability to significantly increase the solubility of insoluble or slightly soluble organic compounds, and the solution is transparent, which is called solubilization.
Bubble aggregates separated by liquid films or solid films are called foams, which can be divided into liquid foams and solid foams. In liquid foam, the interface between liquid and gas plays a major role. Generally speaking, when the surface tension is low and the film strength is high, the foaming power of stable foam and unstable foam is good. The viscosity of solution plays an important role in foam stability in two aspects: on the one hand, it enhances the strength of foam liquid film; In addition, the surface viscosity is high, and the membrane liquid is not easy to flow and discharge, which delays the rupture of the liquid membrane and enhances the stability of the foam.
The defoaming effect can be divided into two types: foam breaking and foam suppression. Substances that have the ability to break bubbles are called foaming agents. An effective defoamer should not only break bubbles quickly, but also prevent the formation of bubbles for a long time.
Washing and decontamination are the most widely used and practical basic characteristics of surfactants. The process of washing and decontamination is extremely complicated, which is closely related to the types and basic properties of dirt, the types and structures of surfactants and additives. The process is a comprehensive effect of various surface phenomena such as adsorption, wetting, penetration, emulsification, dispersion, foaming and solubilization under different conditions.
3 Classification of cosmetics
Cosmetics can clean, protect and beautify people's face, skin surface, hair and mouth. There are many kinds of cosmetics, and the classification methods are different. According to the use site, it can be divided into skin cosmetics, hair cosmetics, nail cosmetics and oral cosmetics. According to the purpose of use, it can be divided into cleaning cosmetics, basic protection cosmetics, beauty cosmetics and aromatic products, and can also be classified according to the dosage form of cosmetics itself.
4 cosmetic raw materials
There are many kinds of raw materials used to make cosmetics, according to statistics, there are about 3000 kinds. According to the proportion of cosmetic raw materials in cosmetics, it can be divided into matrix raw materials and composite raw materials. Matrix raw materials are the main body of preparing various cosmetics, and also become the basic raw materials. Butter, talcum powder, etc. Belonging to matrix raw materials; Composite materials are auxiliary materials used to improve some properties of cosmetics and give them color and fragrance, such as emulsifiers, antioxidants and preservatives in creams. Although the proportion of ingredients in cosmetics is very small, it has a great influence on the quality of cosmetics. There is no absolute boundary between them. One kind of raw material plays the role of matrix raw material in cosmetics, while it may only play the role of auxiliary raw material in another kind of cosmetics.
4. 1 matrix raw materials
1) oil and fat
Oil is the basic raw material of cream cosmetics, which mainly plays the role of skin care, smoothness and moisturizing. Fatty glycerides are the main components of animal and vegetable oils. At room temperature, they are called oils in liquid state and fats in solid state. According to the source, it can be divided into vegetable oil and animal oil. Vegetable oils and fats include coconut oil, olive oil, castor oil, almond oil, peanut oil, soybean oil and palm oil. Animal fats include butter, lard, mink oil and turtle oil. Hydrogenated products of these animal and vegetable oils are called hardened oils. Hardened oils commonly used in cosmetics include hardened coconut oil, hardened butter, hardened castor oil and hardened soybean oil.
2) wax
Wax is an ester composed of high-carbon fatty acids and high-carbon fatty alcohols. It is mainly used as a fixing agent in cosmetics to increase the stability of cosmetics, adjust its viscosity, improve the melting point of liquid oil, and produce a soft effect on the skin when used. According to different sources, wax can also be divided into plant wax and animal wax. Plant waxes include carnauba wax, Jojoba wax and candelilla wax. Animal waxes include beeswax, lanolin wax, whale oil and insect wax.
3) High carbon hydrocarbons
Hydrocarbons used in cosmetic raw materials mainly include alkanes and alkenes. Their main functions in cosmetics are to dissolve and purify the skin surface, form a hydrophobic oil film on the skin surface, inhibit the evaporation of water on the skin surface and improve the efficacy of cosmetics. The main products used in cosmetics are squalane, vaseline, liquid paraffin and solid paraffin.
4) powder
Powder is the matrix material of powder cosmetics such as perfume powder, talcum powder, rouge, tooth powder and toothpaste. Generally, it is a solid insoluble in water, and it is a fine powder made by grinding, which mainly plays the roles of covering, smoothing, absorbing, adsorbing and rubbing. The powder raw materials commonly used in cosmetics mainly include talcum powder, kaolin, titanium dioxide and so on.
5) solvent
Solvent is an indispensable ingredient in cream, cream and liquid cosmetics, including water, ethanol, butanol, pentanol and isopropanol. In the formula, the solvent is matched with other ingredients, so that the product has certain physical and chemical properties and is convenient to use. In cosmetics, besides the solubility of solvent, it also makes use of its properties such as volatilization, wetting, lubrication, plasticization, fragrance retention, antifreeze and convergence.
4.2 Mixed raw materials
1) perfume
Cosmetic perfume is one of the key raw materials. The perfume used in cosmetics should not only choose the appropriate fragrance type, but also consider whether the perfume has any influence on product quality and use effect, such as the influence of color on frost and milk. Lipstick, toothpaste and other products should consider toxicity; Products directly applied to the skin should pay attention to the irritation to the skin.
2) Antioxidants
Cosmetics containing oils and fats, especially cosmetics containing unsaturated bonds in raw materials, are easily oxidized and deteriorated, so antioxidants must be added to prevent raw materials from oxidation. Antioxidants used in cosmetics include phenols, quinones, amines, organic acids, alcohols and esters, inorganic acids and their salts.
3) preservative
Cosmetics contain water, colloid, fatty acids, lipids, protein, hormones and vitamins, which are easy to cause microbial reproduction and deterioration. Preservatives must be added to ensure the quality of cosmetics. Preservatives used in cosmetics include parabens, alcohols, spices and phenols.
4) Pigment
Pigments used in cosmetics include organic synthetic pigments, inorganic pigments and natural pigments.
5 cosmetic requirements of surfactants
The composition of cosmetic formula is diverse and complicated. In addition to oil and water, there are various functional surfactants, preservatives, spices and pigments, which belong to heterogeneous dispersion system. With the increasing requirements for the dosage form and function of cosmetics, more and more kinds of surfactants are used in cosmetics. Surfactants used in cosmetics should be non-irritating and non-toxic, and should also meet the requirements of colorless, odorless and high stability.
1) Functional requirements of surfactants
Each cosmetic has a specific function, such as covering, cleaning, moisturizing, anti-wrinkle, whitening and fragrance.
2) Compatibility requirements of surfactants
During the shelf life of cosmetics, there may be some stability problems such as water separation, oil separation, delamination, precipitation, discoloration, off-taste, swelling, etc., which are all related to the improper selection of surfactants as emulsifiers. Therefore, the compatibility and compatibility of surfactants used as emulsifiers are required to be good.
3) Commercial requirements of surfactants
After using surfactants, products are required to have good appearance and skin feeling, and products are required to have pleasant aroma, fineness, smoothness, softness, good foaming and spreadability. It should be convenient in production and operation. The lower the cost performance ratio, the lower the product cost, and the higher the product performance, the higher the technical level of the product formula.
4) Safety requirements of surfactants
Because the adverse skin reactions caused by cosmetics can directly affect people's physical and mental health, it is required that the raw materials of cosmetics must be harmless to human body, and there should be no irritation, toxicity, bad smell, allergies and other adverse phenomena to skin, hair and eye mucosa.
5) Hygienic index requirements of surfactants
During the use and storage of cosmetics, there will be health and safety problems such as microbial contamination. Therefore, it is required that the surfactant used as cosmetics should have the performance of anti-microbial pollution.
Six surfactants commonly used in cosmetics
The various functions of surfactants are mainly manifested in changing the properties of liquid surface, liquid-liquid interface and liquid-solid interface, among which the surface (boundary) performance of liquid is the most important. Adding substances into the solvent will greatly reduce the surface tension of the solvent and make the surface state of the system change obviously. These substances are called surfactants. According to whether the surfactant can be dissociated in aqueous solution and the type of charge after dissociation, it can be divided into anionic, cationic, zwitterionic and nonionic surfactants.
1) anionic surfactant
Anionic surfactants commonly used in cosmetics include fatty acid soap, sodium dodecyl sulfate, sodium dodecyl polyoxyethylene ether sulfate, sodium hexadecyl polyoxyethylene ether phosphate and soybean lecithin. It is characterized by its strong cleaning and decontamination ability, and it mainly plays the roles of cleaning, wetting, emulsifying and foaming in cosmetics.
2) Cationic surfactant
Cationic surface sliding agents are mainly primary amines, secondary amines, tertiary amines and quaternary ammonium salts with high carbon alkyl groups, such as octadecyl trimethyl ammonium chloride, C 12 ~ 14 alkyl dimethyl benzyl ammonium chloride and octadecyl dimethyl sodium chloride. They are characterized by good bactericidal and antistatic properties, and play a role in softening, antistatic, waterproof and color fixation in cosmetics.
3) zwitterionic surfactant
Amphoteric surfactants commonly used in cosmetics include cocoamidopropyl betaine and imidazoline. Amphoteric surfactants are characterized by good washing performance, gentleness, low toxicity, low irritation to skin and eyes and good biodegradability. Amphoteric surfactants are often used in combination with anionic or cationic surfactants, which have good compatibility and generally produce synergistic effects. It has the functions of softness, antistatic, emulsification, dispersion and sterilization in cosmetics.
4) nonionic surfactant
Non-ionic surfactants commonly used in cosmetics mainly include: sorbitan monolaurate (Span-20, Span-40, Span-60 and Span-80), ethylene oxide adducts (Tween -20, Tween -40, Tween -60 and Tween -80), lauryl polyoxyethylene ether, diethanolamide of coconut oil acid, monoglyceride of oleic acid and polyoxyethylene.
In addition to the above surfactants, natural surfactants (such as lanolin and lecithin), biosurfactants and silicone surfactants have developed rapidly recently.
7 Application of Surfactant in Cosmetics
With the development and application research of surfactants, its application scope is expanding day by day. At present, surfactants have become the main components of washing products, and also have many important applications in cosmetics, such as emulsification, dispersion, solubilization, foaming and cleaning.
1) emulsification
Emulsification is the phenomenon that water-insoluble substances are emulsified evenly in water to form emulsion. Emulsifiers are mainly used in cosmetics, producing creams and lotions. Common powder cream and neutral cream are 0/W emulsion, which can be emulsified with anionic emulsifier fatty acid soap. Emulsification with soap is easier to prepare emulsion with less oil, and gelation of soap can make it have higher viscosity. For cold cream containing a lot of oil phase, the emulsion is mostly W/O type, and natural lanolin with high water absorption and viscosity can be used for emulsification. At present, nonionic emulsifier is the most widely used because it is safe and has low irritation. The famous sorbitan fatty acid ester (Span) and its ethylene oxide adduct (Tween) are good composite nonionic emulsifiers. Span is lipophilic and Twain is hydrophilic. When they are mixed and applied to O/W emulsions, emulsions with good stability and high skin friendliness can be formed.
2) solubilization
The phenomenon that the solubility of slightly soluble or insoluble substances increases is called solubilization. When surfactant is added to water, the surface tension of water will drop sharply first, and then micelle of surfactant molecules will be formed. The concentration of surfactant used to form micelles is called critical micelle concentration. When the concentration of surfactant reaches the critical micelle concentration, micelles can attract oil or solid particles to the lipophilic end, so the solubility of slightly soluble or insoluble substances can be increased.
Solubilizers in cosmetics are mainly used to produce emulsions, hair restorers and conditioners. Surfactants used as solubilizers should have high hydrophilicity, HLB >: 15, such as polyoxyethylene hardened castor oil, polyoxyethylene castor oil, fatty alcohol polyoxyethylene ether, fatty alcohol polyoxyethylene polyoxypropylene ether, polyoxyethylene sorbitan fatty acid ester, polyglycerol fatty acid ester, etc.
Oily ingredients in cosmetics, such as perfume, oil, oil-soluble vitamins, etc., have different solubilization forms because of their different structures and polarities, so it is necessary to choose appropriate surfactants as solubilizing agents. For example, the solubilizing object of cosmetic water is perfume, oil and medicine, so alkyl polyoxyethylene ether can be used to solubilize it. However, alkylphenol polyoxyethylene ethers (OP and TX) are generally not used because of their strong solubilization ability, but they are irritating to eyes. In addition, castor oil-based amphoteric derivatives have excellent solubility in perfume oil and vegetable oil, and these surfactants are not irritating to eyes, so they are suitable for preparing cosmetics such as non-irritating shampoo.
3) Dispersion
The phenomenon that water-insoluble substances form particles in water and disperse evenly is called dispersion. The dispersion system of cosmetics includes powder, solvent and dispersant. Powder can be divided into inorganic pigments (such as talc, mica, titanium dioxide and carbon black). ) and organic pigments (such as phthalocyanine blue, etc. ), which mainly makes cosmetics have good color tone, can cover the background color, and has good use feeling and sunscreen effect; Solvents are divided into water system and non-water system; As a medium, dispersant is hydrophilic (suitable for water system) and lipophilic (suitable for non-water system). So the system has many combinations.
Many surfactants used as dispersants are both emulsifiers and dispersants, such as fatty alcohol polyoxyethylene ether, sorbitan fatty acid ester, fatty alcohol polyoxyethylene ether phosphate, alkyl ether carboxylate and alkyl sulfonate. They all have good dispersion performance. In order to fully disperse the powder in the liquid, it is necessary to make the liquid well wet the surface of the powder. Therefore, when selecting surfactants, HLB of powder surface and dispersion medium should be considered first. Generally, when lipophilic powder is used in water-based system, hydrophilic surfactant should be the main one.
4) Cleaning function
Personal cleaning products mainly include shampoo, shower gel and facial cleanser. In addition to the functions of cleaning, foaming and moistening, at present, the main consideration is the gentleness to the skin, which requires surfactants not to damage epidermal cells, not to act on the protein of the skin, and not to penetrate the skin or less, so as to keep the skin oil and the skin itself in a normal state.
Anionic surfactants have been used for cleaning for a long time. The decontamination ability of soap is incomparable with other detergents. Sodium dodecyl sulfate is a commonly used raw material in cleaning series cosmetics, which can make the skin achieve good cleaning effect. Amphoteric surfactants, such as imidazoline, cocoamidopropyl betaine and amino acids, are all mild cleaning surfactants, and are indispensable ingredients for preparing high-grade facial products, hair care shampoos and baby shampoos.
5) Flexibility and antistatic effect
Cationic surfactant is the main conditioner in hair care products such as conditioner and conditioner, which has good softness and antistatic ability and plays a unique role in hair softening conditioner. The most widely used cationic surfactants are monoalkyl and dialkyl quaternary ammonium salts, that is, C 16 ~ 18 monoalkyl ammonium salt, bis -C 16 ~ 18 alkyl quaternary ammonium salt and alkyl benzyl quaternary ammonium salt. Asymmetric tallow base, octyl dimethyl quaternary ammonium salt and 3- hexadecyl methyl ammonium salt have good effects on dry combing, wet combing and debonding of hair. Recently, quaternary ammonium salts derived from wool fatty acids have attracted wide attention. They are less irritating, have the characteristics of water retention, wettability and cationic surfactant of lanolin, and can give hair a unique touch such as moisturizing and softness.
6) Wetting and infiltration
As a cosmetic, it should not only have a cosmetic effect, but also feel comfortable and soft when used, which are inseparable from the wetting effect of surfactants. In this regard, biosurfactants have made remarkable achievements. As an important component of biological cells, phospholipids play an important role in cell metabolism and cell membrane osmotic adjustment, and have good moisture retention and permeability to human skin. Sophora japonica glycolipid biosurfactant has a peculiar affinity to the skin, which can make the skin feel soft and moist. Biochemical active substances, vitamin derivatives, enzyme preparations, cell growth factors (EGF, DFGF), collagen, elastin, ceramide, hyaluronic acid, etc. Prepared by biochemical synthesis and other methods. These substances can penetrate into the skin, participate in the metabolism of skin cells, and change the skin tissue structure. When used in cosmetics, it can achieve anti-wrinkle, anti-aging and whitening effects.
8 Development trend of surfactants for cosmetics
2 1 century cosmetics industry will improve the safety, efficacy and environmental protection of cosmetics by integrating the high-tech achievements of modern multi-disciplines, develop new cosmetic raw materials and adopt environmentally friendly surfactants, which is the focus of cosmetics research. In addition, biochemical active substances have been widely used in cosmetics.
1) biosurfactant
Biosurfactant is a new discipline developed in the field of international bioengineering at the end of 1970s. Biosurfactants are favored by people because of their wide sources of raw materials, low price, high surface activity, strong emulsifying ability, good foaming ability, non-toxicity, environmental protection, complete biodegradation, good biocompatibility, no sensitization and digestibility.
2) alkyl glycoside
Alkyl glucoside (APG) is a kind of nonionic surfactant synthesized from renewable plants such as fatty alcohol and glucose, and has become the representative of a new generation of nonionic surfactants with superior performance. Structurally, APG is a new type of surfactant, which combines the characteristics of nonionic surfactant and anionic surfactant. APG is not only high in surface activity, rich and stable in foam, strong in detergency, but also non-toxic, non-irritating, good in compatibility with skin, fast and thorough in biodegradation, good in compatibility with other surfactants, and has remarkable effects in conditioning and maintaining hair styles. APG has many excellent performances in safety and environmental compatibility.
3) Chitosan
Chitosan (scientific name: chitosan) is a natural cationic polysaccharide obtained by deacetylation of chitin, and it is a natural polymer compound with abundant resources and low price. Chitosan is soluble in dilute acid, and the highly deacetylated product is soluble in water. Many active groups such as amino groups and hydroxyl groups in the molecule can show new properties after chemical modification. Chitosan has good antibacterial property, antibacterial property, surface activity, moisture absorption and moisture retention, film forming property and flocculation property. Because chitosan is a rare positively charged polymer in nature, it has unique functions in many fields. This kind of polysaccharide has excellent properties such as biodegradability, good film-forming, good biocompatibility and certain antibacterial property, and has good compounding and stability with emulsifier in cosmetics. Products used in hairdressing can keep hair shiny, soft, easy to comb and antistatic; Products used for skin care and beauty can make the skin have good conditioning performance, and are widely used in cosmetics, medicine, food, chemical industry, environmental protection and other industries, and are known as universal polysaccharides. Chitosan, chitosan derivatives and chitosan oligosaccharides can be used in various cosmetics. The application of chitosan in cosmetics will become a new trend in the future, and its excellent moisturizing, antibacterial, physiological activity and excellent compatibility will make it have a broad application prospect in cosmetics.
4) Sucrose fatty acid ester
Sucrose fatty acid ester is an ester produced by the reaction of C 12 ~ 22 fatty acid with sucrose. It is a safe, non-toxic, pollution-free and 100% biodegradable nonionic surfactant. Sucrose fatty acid ester is non-toxic, odorless, non-irritating to skin and mucosa, and easily biodegradable. By controlling the carbon number and esterification degree of fatty acid residues in sucrose fatty acid esters, or mixing sucrose esters with different esterification degrees, a variety of HLB products can be obtained, making them both 0/W and W/0 surfactants. Sucrose fatty acid ester has many properties such as emulsification, solubilization and foaming. Since 1960s, it has been widely used in daily chemical, food and medicine industries abroad. However, there are still many problems in the research of sucrose fatty acid esters in China. We should take active measures to develop diversified products, stabilize production technology, carry out more in-depth theoretical research and broaden the application fields of sucrose fatty acid esters.
5) Lecithin
Lecithin is a natural biosurfactant, which is known as "brain gold" and many researchers call it "the greatest healthy food in 2 1 century". Phospholipid surfactant is a special surfactant with surface activity and biological activity, and its application field has been extended to food, medicine, cosmetics and various industrial additives. Lecithin can activate skin, keep skin moist and prevent skin dryness in cosmetics. At the same time, lecithin can also improve the dispersibility and foaming of cosmetics, and make hair bright, moist and soft when used as a hair lubricant.
6) Special surfactants
Special surfactants refer to surfactants containing elements such as fluorine, silicon, phosphorus and boron. Silicone surfactant has the advantages of low toxicity, oxidation stability and thermal stability, lubricity, antistatic property, defoaming and foam stability, good peelability and physiological inertia, and has a strong performance of reducing surface tension. It is a surfactant with special functions. Silicone used in cosmetics can increase the lubricity and water resistance of skin and increase the luster of products. Silicone surfactants have high physiological inertia and high safety when used in cosmetics. In cosmetics, silicone surfactants are loved by consumers for their excellent properties such as smoothness, softness, luster and elegance. I found this for your reference.