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scientist terms
COSMETOLOGY
Oils and butters in cosmetics
Triglycerides are the result of the process of esterification of glycerol with fatty acids, in the field of cosmetology have widespread use, not only in the preparation of soaps, but also in quelladiemulsioni and OleOle.
And 'possible to classify the triglycerides according to their origin, natural or synthetic.
The lipids include triglycerides of natural fluids (oils) and consistent (butters) extracted from plants, particularly seeds and fruit pulp. Compared to synthetic ones, the triglicerdi natural, rich in unsaturated, have the problem rancidity, are unstable to heat and light and their use may be limited by the smell very strong.The rancidity problem can be partially solved by the use of antioxidant molecules in the formula. In addition, triglycerides are natural, with some exceptions, a touch on the skin is not always the most pleasant and are difficult to implement due to the low diffusibility on the skin. The benefits, however, are represented by high eudermicità, then from the strong affinity to the skin, and natural origin. Beyond the sensory characteristics, the value of an oil or butter are defined by the portion of the unsaponifiable fraction. In principle, for the unsaponifiable triglycerides means that fraction that can not be extracted with the normal process of saponification. In short, the unsaponifiable fraction of vegetable oils is all that nature has no triglycerides, consists of approximately 1-2% of the total and includes several molecules, such as hydrocarbons (karitene, n-eicosano, Prista, squalene) , carotenoids (α, β, γ-carotene, lycopene), xanthophylls (lutein, flavoxantina), α, β, γ, δ-tocopherols, aliphatic alcohols (basseolo, hops, butirospermolo, parkeolo), terpenes and phytosterols(stigmasterol, β-sitosterol, brassicasterol, campesterol, spinasterolo). This fraction is given a certain importance, but also cosmetic technological interest because it contributes to stabilitàdeitrigliceridi.
As already mentioned, within the class of glyceric esters are oils and butters.
The oils of triglycerides in cosmetics
The natural oils used in cosmetics more triglycerides are: avocado oil, safflower oil, macadamia oil, sesame oil, sweet almond oil and wheat germ oil.
Avocado oil is most commonly used, due to its high content of
unsaponifiable, vitamins and lecithin. It has a good flavor and good texture. It has a good filtration capacity against UV rays.
Safflower oil is very popular in the United States of America primarily because of the high oxidation stability, despite the high degree of unsaturation. The main characteristic of safflower oil is a great moisturizer.
Macadamia oil has a high content of palmitoleic acid. Its fatty acid composition is similar to that of sebum, then - given the high eudermicità - lends itself very well for an application to the skin.
Castor oil consists primarily of ricinoleic acid. It looks like a very viscous oil, then used in the formulation of makeup, is a good dispersant for pigments and imparts gloss in lipstick.
Sesame oil has a good balance between saturated and unsaturated acids, a good content of unsaponifiables and antioxidants. is one of the better oils that filters UV rays.
The sweet almond oil is light in color and is odorless. Mainly used in products for sensitive skin and paidocosmesi, has high emollient.
The wheat germ oil has good antioxidant activity, due to its high content of vitamin E and phytosterols.
Among the synthetic esters, the most widely used is the triglyceride Caprylic / capric. And 'stable to oxidation because of its lack of unsaturation and has a good texture.
BUTTERS in cosmetics
The fat butters are high consistency, those are the most frequently used shea butter
and cocoa. Both butters have a high content of unsaponifiable. The first (INCI: Butyrospermum departed Butter), is used for the preparation of products for dry skin, redness and sun products. Cocoa butter (INCI: Theobroma Cacao Butter) is a major component in the formulations of the stick for lips.
Waxes in cosmetics
This category includes both foreign synthetic waxes of plants and animals. An ester is derived from a chemical reaction that involves an acid and an alcohol.From this reaction may lead to a wide range of esters, fatty acids and because there are many many alcohols and glycols. The physical form of foreign non-glyceric (solid, liquid) depends mainly on the total number of carbon atoms, the presence of branching and / or saturation and hydroxyl functions.
Among synthetic esters can find Cetyl Lactate, the Tridecyl Stearate, Stearyl the Stearate, Oleyl Oleate the, Ethylhexyl Palmitate, C12-15 Alkyl Benzoate.For a formulator, the choice of an ester over another, is made based on several factors, such as the type of product, compatibility with other ingredients, the application site, etc..
Is very difficult to correlate the chemical structure and sensory characteristics, such as spreadability, time of writing, skin feel and after feel. In general, the higher the number of carbon atoms increases emollient and feeling fat and decreases the spreadability.
Among the natural waxes include:
Jojoba oil (Simmondsia Chinensis Oil INCI EU, USA INCI Simmondsia chinensis (Jojoba) Seed Oil)
Candelilla Cera (Candelilla Wax INCI EU, USA INCI Euphorbia cerifera (Candelilla) Wax),
Cera Carnauba (Carnauba Wax INCI EU, USA INCI Copernicus cerifera (Carnauba) Wax)
The Beeswax (Cera Alba INCI EU, U.S. Beeswax INCI)
Lanolin derivatives cones.
Jojoba oil is the only vegetable oil triglycerides is not the source, then it is classified as a wax. It is extracted from the seeds of Simmondsia chinensis, an evergreen shrub that grows on dry land. Despite the high unsaturation, Jojoba oil is very stable to oxidation. It looks like a more or less intense yellow liquid with a pleasant smell. Jojoba oil is used in all those products with emollients, through a process of hydrogenation are obtained with spheres of activity exfoliating.
Candelilla wax is obtained from the branches of Euphorbia cerifera. This plant is very common in Mexico and southern United States. Candelilla wax comes as a yellow solid with a melting point between 70 and 75 degrees centigrade. It is used mainly in mergers lipid (sticks and lipsticks), because it gives rigidity to the preparation, brilliance and strength.
Carnauba wax is obtained from the leaves of the carnauba palm, a tree that is typically found in the north of Brazil. Carnauba wax is presented as a solid yellow color, with a melting point high enough (80 - 85 ° C). It is used in formulations for stick and is often used as an alternative to candelilla wax.
Beeswax is a secretion dell'Apis mellifera. This wax is extracted from the comb. Presents the appearance of dark color, but is purified to obtain a yellowish-white product.
The melting point of beeswax is about 62 to 70 ° C. Beeswax and all its substitutes are used in formulations to give consistency to emulsions, ointments and mergers lipid.
Lanolin
Lanolin is a substance, yellowish, oily to the touch, odor and very intense. From the chemical point of view, lanolin is not a fat, but a wax. Nevertheless, more often than many people - to be deceived by its consistency - classify it as a fat, using the synonym "wool grease". In fact the error is obvious, as is lanolin-free glycerin and as such, similar to wax.
Lanolin is accumulated on the fleece of sheep (wool coat), after being secreted by the sebaceous glands of the animal. Its functions reside mainly in the protection from the elements and dehydration. Not surprisingly, therefore, its current applications in numerous products designed for beauty and skin care man.
Chemical characterization
At the sight, lanolin shows a yellow more or less intense depending on the purity of the wax, and exhibits a smooth texture to the touch, just like fat.
Lanolin has a strong smell, which can be reduced by industrial processes of deodorizing activated carbon.
The melting point of the lanolin is not very high indeed, melts at 38 degrees Celsius or so. Lanolin is not water soluble, but is able to incorporate a certain amount of water without losing consistency.
Lanolin is used in emulsions, products softening, smoothing in cosmetics in ointments, and cosmetic products in the sticks suitable for hair care and hair.
Composition of lanolin
How many natural products, including lanolin has a very complex composition and variable. Mostly, lanolin is made - for 97% of its weight - esters of long chain fatty acids. The remainder is represented by alcohols and lanolin acids.
Production of lanolin
Lanolin is extracted from wool by washing in hot water and special detergents.In this way, lanolin, but also fats and other compounds are removed from the wool.
Lanolin extracted is continuously removed during washing and subjected to a process of purification (centrifugation), after which it is concentrated by melting at 38 degrees Celsius.
Lanolin derivatives
From lanolin, through special chemical processes, you can get different products, used in cosmetics as lipid excipients. The main derivatives of lanolin are:
• LANOLIN ACETYLATED;
• LANOLIN hydrogen;
• LANOLIN hydroxyl;
• lanolin ALCOHOLS;
Acetylated lanolin is derived through a process of acetylation of lanolin. The acetylated product is used in ointments, and powders in mergers. The only flaw is that acetylated lanolin no emulsifying activity.
Hydrogenated lanolin is the end product of the process of hydrogenation of lanolin. It has good emulsifying activity and as such is used in emulsions, both in the water in oil than in oil in water.
Hydroxylated lanolin has good emulsifying activity. It is used as a stabilizer for oil in water emulsions, and as the emulsifier in water in oil. In addition to this feature exhibits a good compatibility with anionic emulsifiers, cationic and nonionic surfactants.
The lanolin alcohols are mixtures of alcohols obtained by 'hydrolysis of lanolin.These mixtures of alcohols are preferred because they confer to lanolin classical to the final product an odor less unpleasant and less sticky consistency. Although alcohols have a good emulsifier functionality, both in the emulsion W / O than in O / A. The cosmetic products which may include in their formulation of lanolin alcohols are the day and night creams, the basis for lipsticks, hair products, cosmetics and massage oils, the sticks, soaps and depilatory creams.
Application of lanolin
Lanolin and its derivatives are particularly suitable for use in cosmetic formulations to the skin and body care. In the past, sailors used lanolin to create a sort of thin skin protection against water and other possible problems due to dehydration from salt water or wind. Lanolin is also used in products to help train the cholecalciferol or vitamin D3.
Many women who are breastfeeding lanolin in a gallant remedy, because it allows the skin to regenerate and to soften the sting due to incorrect sucking child.
In addition, lanolin recognizes other areas of employment which is not the aesthetic treatment of the body and skin. It can be used in clothing, in sport and in the music.
Applied on garments that have decorations made from natural hair, lanolin may provide some protection against water. In sports, especially baseball, lanolin is applied to the leather glove to make it soft, hydrated and resistant to breakage due to excessive dehydration. Finally, lanolin can also be used in music as a lubricant to facilitate the mounting of the brass instruments.
Comments
Lanolin is a potential allergenic agent. To reduce allergic symptoms due to lanolin alcohols, the European Union has decided that all cosmetic products containing lanolin should label bearing the words "product containing lanolin."
Cosmetic cleansing action
Under this definition includes those particular substances to surface action with foaming properties, wetting agents, detergents, emulsifiers and water soluble.Molecules are amphiphilic in nature, consisting of a hydrophobic part (tail polar) and hydrophilic (polar head). The charge does not possess the lipid while the hydrophilic part of the molecule may possess one or more negatively charged (anionic), positive (cationic), both charged (amphoteric) or have only charged hydrophilic POE chains such as hydroxyl or (not ion). The surfactants act as, thanks to their dual nature, tend to arrange themselves or to adsorb at the interface between the various surfaces, such as air-water or water-oil. This positioning creates two distinct mechanisms: the lowering of surface tension and / or stabilization of the interfaces through the formation of adsorbed layers.The effect of wetting and foam depend mainly on the first mechanism, while the effect of emulsifier and solubilizer in the second. The cleaning effect is instead the result of both.
SURFACE TENSION
Surface tension is a property of fluids due to the interactions that take place between the molecules that make up the fluid itself.
The molecules located inside the liquid is subject to attractive forces acting in all directions and cancel each other out, while those placed on the surface are attracted only to the center of mass. The action of these cohesive forces causes the surface layer of molecules to act as a "membrane" that surrounds the substance itself. This force is called surface tension surface, whose intensity depends on the type of liquid that has considered and affinity with the substance that surrounds it.
A surfactant, placed in water in small quantities, tend to arrange themselves at the water surface with the polar part of the molecule in contact with air: the surface tension of water is greatly diminished.
A practical example of the activity of surfactants is the removal of dirt present on the skin surface. The skin of our body acts as a solid, and dirt is the liquid that settles over. The dirt on our skin is to form a sort of lens whose shape is generated by the existence of its own surface tension.
In this situation you have different surface forces:
• between the skin and dirt γ = S / P;
• between dirt and air γ = S / A.
If you put water in contact with the dirt, that is deposited on top simply by creating an additional interfacial tension γ represented with dirt / water.
In addition, the water is in contact with the air in turn generates a surface tension of air / water.
The surfactant greatly improves the ability of water washing, because the polar head oriented toward the water and the tail toward the polar favors removing dirt. The surfactant forms micelles that incorporate the filth of their affinity with the lipid with the fat present in the dirt. Thanks to the mechanical action of washing the micelles are removed along with water.
Detergents are essential for personal hygiene, but it should be noted that if used excessively, may also be aggressive because they remove the hydro-lipid film of the skin.
Usually a detergent is a mixture of compounds with different functions: washing surfactant function, humectants and / or with the task of re-fatting hydrate and replenish the skin's protective lipid layer.
In the formula, there are other additives with ancillary features: eg. inorganic salts that increase the plasticity and the melting temperature of the soap, opacifiers and pearling substances, dyes and perfumes deputies to improve the organoleptic characteristics of the product, antioxidants with protective function by the formation of free radicals, chelating agents to prevent the formation of precipitates insoluble in water, etc..
Equation of cleansing
Let's see how does the soap to remove dirt from the skin.
Consider the angle theta (θ) formed by the lens of dirt placed on the skin, which is the wettability of solids than liquids.
If this angle is less than 90 degrees, the skin is "wet" from the dirt, so dirt is closely adherent to the skin.
Is expressed as the phenomenon of detergent, the angle theta (θ) increases until reaching a width between 90 and 180 degrees. After cleaning of the act, the angle θ is equal to 180 °, the situation where the dirt is completely detached from the skin.
The equation for the cleansing explains the relationship between surface tension and wetting angle.
The cosine of the angle θ is equal to a ratio: the numerator we have the γ Leather / Skin Cleanser which removes the γ / Dirty. In the denominator we have the surface tension between Dirt / Water.
In other words, the cosine of the angle of contact is equal to the ratio that creates tension between the detergent and leather, a lessening of the skin and dirt, and water power - filth.
The cosine of θ is -1 when the angle is 180 °. If the cosine of θ -1 measuring the voltage between the skin and grime is equal to zero, because the dirt comes off.
Finally, the tension between the skin and detergent is the same - γ Dirt / Water.
These steps describe a basic idea: as the cleansing increases, the tension between the skin and mild increases and decreases the surface tension between the dirt and water.
Soaps and detergents
The soaps or surfactants are the salts of long chain fatty acids.
A surfactant is formed by a chain lipophilic (fat soluble) and a hydrophilic head (water soluble).
The following is the general formula of surfactants:
where R represents a carbon chain formed by a number of coals between 11 and 17.
The short chain R can be saturated (C11 to C13, soft soap) or saturated long (C13 to C17,
solid soaps), but also unsaturated (liquid soaps). X + is defined as the counterion of the hydrophilic head, since the soap is a salt of fatty acids.
This is usually given by the ion against sodium or potassium.
The sodium ion is used for solid soaps, but the potassium ion is used for soft soaps and / or liquids. Remember that the counterion does not participate in the cleansing surfactant activity EVER! The activity is guaranteed by washing hydrophilic head and lipophilic tail R.
How do you get a soap?
At this point, first to understand how we get a soap, you have to explain quickly what are triglycerides or glycerol-triacil.
Triglycerides are fats abundant in nature, which can have both animal and vegetable origin.
Triglycerides are esters of fatty acids. As such, they are composed of glycerol and three fatty acids, which may be saturated, unsaturated or polyunsaturated. If the hydroxyl groups of glycerol are esterified with three fatty acids identical, triglycerides that are going to be called simple. Instead, if the hydroxyl groups are esterified with different fatty acids, the formats are called mixed triglycerides.
To get a hot soap must be reacted triglycerides with a solution of concentrated sodium hydroxide, or with a solution of potassium hydroxide to 20%.
From this reaction you get glycerin (or glycerol), soap and water (still in the salt solution as it is detached from the triglyceride fatty acids). To precipitate and purify the soap must be made through a process of salting the solution, adding the classic sodium chloride. In this way, the salt binds water by precipitating the soap.
Possible incompatibility of soaps
The main problems associated with the production of soap are three. The first is from an incompatible ion hard water, the second from an incompatible to the pH of hydrolysis and the third instability at acidic pH.
1. INCOMPATIBILITY OF HARD WATER SOAP ION.
Running water has a variable concentration of ions hard.
The ions that cause water hardness are calcium, iron and magnesium.
When washing, soap comes in contact with hard water, giving rise to a chemical reaction.
The surfactant reacts with magnesium chloride, giving rise to a precipitate insoluble salt. In this case, the surfactant activity of the soap is significantly reduced, in short, the soap does not wash well!
R-COO-Na + + MgCl2 = (RCOO) 2 + Mg 2NaCl
To reduce the formation of insoluble salt precipitates is necessary to add a binder to our soap.
The chelating agent such as ethylenediamine tetraacetic acid or EDTA, a particular molecule is able to incorporate into the structure of the cations, resulting in very stable complexes. With the formation of these complexes, the metals do not precipitate but remain embedded in the solution.
2. pH of hydrolysis.
Another problem is the pH of the soap. When the soap is in contact with water hydrolyses, because it is a salt, giving rise to the corresponding acid and the corresponding base.
R-COO-Na + + H2O = RCOOH + NaOH (or KOH)
This is a problem, because the soda or potassium hydroxide are strong bases that can increase the pH up to about 10. In the presence of water we have some very basic changes in the pH of our skin, which is 5.5. To overcome this problem there are basically two solutions. The first solution consists in replacing the strong base, while the second solution is to use other surfactants.
3. INSTABILITY OF A SOAP acid pH.
Suppose to react with the soap a weak acid such as acetic acid. By analyzing the reaction can be said that the reaction has moved from weak acids.
R-COO-Na + + RCOOH + CH3COOH = CH3COO-Na +
From this reaction you get the salt of acetic acid, which is sodium acetate. This salt precipitates out free fatty acid. We then discovered that in the presence of an acid pH soap is no longer able to exercise their cleansing activity.
Classification of surfactants
The properties that can be attributed to surfactants are mainly four:
1. foaming (interface liquid / air);
2. wetting power interface (solid / liquid);
3. cleaning power interface (liquid / liquid / solid);
4. emulsifying power interface (liquid / liquid);
5. Solubilizing power interface (liquid / liquid).
For foaming is the ability to produce foam and is typically only a property of certain classes of surfactants. Particularly interested in the interface between water and air where the surfactant have the corner facing the air lipophilic and hydrophilic head towards the water. Remember that a composite foam is not always a good power washing.
The wetting power is the ability to reduce the contact angle that is formed by placing a drop of a liquid on a solid surface. We are looking for a good wetting is required when a close contact between the solution containing the surfactant and the substrate (for example in hair dye products, which are uniformly cover the hair).
The cleaning power is the ability of the surfactant to remove dirt from skin and hair.
The emulsifying power
is the ability to dispose of a surfactant at the interface between two immiscible liquids, like water and oil, and to form micellar structures that prevent the coalescence of droplets that are formed by applying a shear force. This effect is exploited for the preparation of cosmetic emulsions.
The emulsion can be of two types:
1. OIL IN WATER (droplets of oil dispersed in the external aqueous continuous phase);
2. OIL IN WATER (water droplets dispersed in the external oily continuous phase).
The solubilizing power is always related to the ability of the surfactant to place themselves at the interface of two immiscible liquids and is used in the preparation of the type of products that need to maintain transparency (for example, the solubilization of a perfume in a tonic aqueous).
Classification of surfactants
Surfactants are classified according to the nature of their polar fraction:
Anionic - have a negative charge.
Cationic - have a positive charge.
Amphoteric - have both charges, either positive or negative.
Nonionic - do not have a net charge, but polar groups (eg hydroxyl functions).
In turn, these categories are then divided into other subcategories:
1. Anionic
• Eterosaponi;
• Lipoproteins;
• derivatives of amino acids (and acilglutammati acilsarcosinati);
• Sulphuric esters;
• Solfonsuccinati;
• sulphonates (BABS and LABS).
2. Tenside CATIONIC
• Benzalconiocloruro;
• cetyltrimethylammonium bromide.
3. Tenside Amphoteric
• Betaine;
• Solfobetaine;
• Alchilbetaine.
4. Tenside NON IONIC
• ETHERS
PEG;
Alkyl glucosides;
• FOREIGN
Ethoxylated fatty acids;
Foreign obtained from glycols or glycerol;
Derivatives of sorbitol;
Sucrose esters;
Alcanolammidi (MEA, DEA, MIPA);
Anionic
CH3 - (CH2) n - COO-X +
The anionic surfactants have a negative charge in the polar head. They were the first to be used in detergents and are still the most used due to good scrubbing and foaming properties and low cost.
As mentioned, the counterion X + does not affect the ability of detergent surfactant, but it affects the physical and chemical properties: solubility, physical state and also the pH in aqueous solution. Depending on the nature of the polar head, are more or less sensitive to hydrolysis: the sulfates are more susceptible to hydrolysis, while sulphonates are the most stable.
From the point of view of skin tolerance, the surfactants are more aggressive and can cause irritation phenomena, especially on sensitive and reactive skins.
They can be divided into several subcategories: ETEROSAPONI, lipoproteins (CONDENSED WITH PROTEIN FATTY ACID), amino acids derivatives, sulfuric esters, the sulphosuccinic sulphonates).
Eterosaponi
R - CH2 - (OCH2CH2) n - OCH2COO - X +
The eterosaponi - or alchilpoliglicoleterecarbossilati - are more hydrophilic than the soaps, which are compatible with hard water, have a good foaming power and are well tolerated by the skin. The only problem is that it can form the eterosaponi 1-4 dioxane, which is a strong carcinogen.
Protein fatty acid condensates
These condensates are obtained by acylation of hydrolyzed protein and fatty acids.
In the image, R indicates the carbon chain derivative of fat, LP and lipoprotein X + counterion.
Lipoproteins
are derived peptides, obtained by enzymatic or chemical hydrolysis of animal proteins (collagen) / plant.
The salient features of these surfactants are: high skin tolerance, ability to reduce the aggressiveness of the alkyl sulfates and naturally derived. For those reasons are commonly used as secondary surfactants, despite their limited foaming. On the market there is a selected number of these compounds, usually obtained by condensing fatty acids of coconut with various hydrolyzed protein, such as collagen, keratin, silk, wheat protein, rice, oats, almonds, etc. ..
Amino acid derivatives
Among the derivatives of the amino acids are glutamate and ACILIA ACILIA sarcosine. The first result dall'acilazione glutamic acid with fatty acids. The latter, however, are derived from sarcosine (N-metilglicina) obtained industrially with formaldehyde, methylamine and HCN.
The acyl glutamates - Disodium cocoyl glutamate as the TEA cocoyl glutamate and - with good skin tolerability, despite the cleansing power.
The acyl sarcosine resent a good solubility in hard water, and thanks to the amide bond have a very good foaming power and good stability at acidic pH.The most acilsarcosinato Sodium cocoyl sarcosine is used.
Sulphuric esters
In this classification, the carbon chain lengths ranging from 12 to 18 carbon atoms ends with a sulfuric acid group-SO3.
The properties of these surfactants are largely dependent on the length of the carbon chain.
The sulphate esters are the most used anionic, because basically they are good cleaners, they are foaming, inexpensive and can be used even in hard water.
Another important advantage for their use is that viscosizzano with the addition of electrolytes (usually sodium chloride): This property is exploited in detergent formulations because it allows to obtain viscous products at low cost.
The best known is the sulfuric acid ester sodium lauryl sulfate (SLS)
used in most shampoos, toothpaste, shaving cream and soap bubbles.
A similar sulfuric acid ester is the alchiletero sulfate.
If you go to analyze the molecule there is always the presence of sulfate group, however, associated with a number of ethoxyl groups, or polyethylene glycol (PEG). With the introduction of these groups, you get an enhanced hydrophilic.Of course, compared to sodium lauryl sulfate, the sulfate is alchiletero much less aggressive and more soluble in water, given the presence of a number of group-OCH2CH2.
They are surfactants that have a certain aggressiveness on the skin, so are usually used in mixtures with other surfactants more delicate.
Sulphosuccinic
The succinic solfonsuccinati derived by acid. Succinic acid is a carboxylic diacid characterized by the presence of two carboxyl units, in turn, linked to two units of ethylene. The derivative that is obtained for the construction of the anionic called solfonsuccinato. This is created through a chemical synthesis reaction, the molecule attacking a group sulfuric acid and esterified carboxyl groups remained one of the two with a free fatty acid. If R1 is made up - you get CH2CH2NHCOC11H23 alcanolammidi or amide derivatives. However, if R1 is formed by - (CH2CH2O) C12H25 alcohol ethoxylates derivatives are obtained.This surfactant is characterized by a reduced irritation compared to the alkyl sulphate, has good cleaning characteristics and does not cause the formation of insoluble salts in the presence of hard water.
The surfactants are used in both solfonsuccinati products for personal hygiene than in cleaning the house.
Sulphonated
The sulfonated surfactants have always sulfonic group, which binds directly to the carbon chain hydrocarbon. The sulphonates are widely used because they possess high characteristics detergents on the other hand, have the disadvantage of being very aggressive and irritating.
The sulfonated surfactants can also be abbreviated as ABS (alkyl benzene sulfonic). In turn, the ABS can be divided into BABS and LABS. The first consist of a branched chain R, because their name is Branched ABS. The LABS, however, are characterized by a linear chain, R, where L stands for Linear ABS.
The LABS are designed to overcome the poor biodegradability of BABS. They are soft because the carbon chain surfactants derived from synthetic paraffin or olein.
Cationic Surfactants
Cationic surfactants have completely different characteristics than the anionic.
From the chemical point of view, exhibit a positive charge is part of the hydrophilic portion. As shown in the figure, the positive charge is conferred by a quaternary nitrogen.
These surfactants are not used as detergents, as washing agents are not good, nor good foaming. The most common use is to substantivizing, particularly on substrates that have negative charges (usually takes the interaction between the negative charges present on proteins of the skin and hair and the positive charge of the surfactant). For this reason their use is limited for use in cosmetic products and substantivizing conditioning effect as hair conditioners, are also useful to eliminate the electrostatic hair after rinsing.
Some cationic surfactants also have a high antimicrobial power comes from the ability to fix, thanks to their positive charge, the membranes of bacterial cells, and causes / Rupture.
Remember that cationic surfactants can cause irritation and are incompatible with anionic surfactants with which they form insoluble salts in water.
The best known are the cationic surfactants benzalkonium chloride and ammonium bromide cetiltrimetil.
Amphoteric
The amphoteric surfactants are characterized by the presence, on the same molecule, both of the charges: one positive and one negative. They can be classified as: betaines, propilamidobetaine, solfobetaine, imidazoline and wisteria.
Among the derivatives we find ALKYL BETAINE Betaine and ALCHILSOLFOBETAINE (also known as sultaine). Their structure is similar to that of amino acids: in fact, have a quaternary nitrogen center with a positive charge and four substituents: an alkyl chain with carbon atoms ranging from C10 to C12, two groups - and a group CH3-CH2COO.
The solfobetaine have the same structure, however, the hydrophilic portion is formed by a group instead of the carboxylic acid sulfuric.
The amphoteric surfactants are normally used in combination with anionic because they can improve their performance, in particular:
1. Improvement of skin tolerance. It seems that the amphoteric, having a higher affinity for the skin than the anionic surfactant preferentially reaches the skin protect itself from aggression of anionic
2. Increase in viscosity. The form of betaine in a ratio of 1:1 complexes with anionic surfactants: this results in increases, although significant, the viscosity
3. Antimicrobial activity. The amphoteric surfactants have a certain antimicrobial activity, linked to the presence of the quaternary ammonium group.
4. Compatible with cationic surfactants. The presence of an amphoteric surfactant in combination with an anionic system makes possible the addition of small amounts (up to 5%) of cationic surfactant with no clouding issues.
Nonionic surfactants
From the chemical point of view, the non-ionic surfactants are molecules that have a net charge in the hydrophilic head, but the polarity is conferred by the presence of oxygen and nitrogen atoms as links in the ethereal, ester and amide found in the structure of the surfactant.
The salient features of nonionic surfactants are those of being insensitive to changes in pH, have a certain degree of thickening, foaming and thickening agent. They are compatible with all other surfactants previously seen (anionic, cationic and amphoteric) and are used in combination with them.
The non-ionic soaps - being characterized by a lack of aggressiveness and a low chance of causing irritation and allergic problems arise, are widely used in cosmetic products for children.
The nonionic surfactants can be classified into different categories, which depend essentially on the structure of their hydrophilic head. Mainly there are two classifications, that of that of ethers and esters, ethoxylated and both can be. For the mean ethoxylation number of groups - (CH2CH2O) inserted in the molecule. The ethoxylated ethers of general formula R1-O-R2, where R1 represents a fatty acid, O is an oxygen atom and R2 is the repetition of a number "n" times of the following units (CH2CH2O) nH. As part of the foreign are esters of fatty acids, esters derived from glycols or glycerol ethoxylates and their derivatives, derivatives of sorbitol, sucrose esters and alcanolammidi.
Alcohol ethoxylates
The main non-ionic surfactants of this category are alcohol ethoxylates. An example of lauryl alcohol ethoxylates is 20 (it is recognized by the ending "eth").The number 20 indicates the average number of ethoxylation, and Laur indicates the fatty acid used, which in this case is the lauric acid.
Alkyl glucosides
This category of nonionic surfactants belong to a series of secondary surfactants, obtained by alkylation of short chains obtained by hydrolysis of glucosidic polysaccharides such as starch. The alkyl glucosides have a very high tolerance skin and eye, good foaming ability, the ability to reduce iiritabilità laurieteresolfato or other primary surfactants anions, compatible with anionic, amphoteric, cationic, biodegradable total compatibility with high doses of electrolytes, high held in the presence of hard water.
The major players in this category are the Coco-Glucoside Lauryl Glucoside and.
FOREIGN
Derivatives of sorbitol
Sorbitol is a natural sugar belonging to the group of polyols. Through the subtraction of a water molecule from its structure gives the compound called sorbitan 1.4. The esters of sorbitol and sorbitan are obtained by a reaction of acylation of the hydroxyl groups, using natural fatty acids such as lauric, palmitic, oleic and lostearico. Sorbitan esters are commonly called (SPAN sorbitan monoesters such as 1.4, 1.4 and Polyethoxylated Triester sorbitan sorbitan), and ethoxylated sorbitan derivatives are called TWEEN, which vary depending on the number of ethoxylation (eg, polysorbate 40, polysorbate 80, etc..).
The TWEEN can be utilized as emulsifiers, surfactants or water soluble. The most used is polysorbate 20, which is widely used as an additive in baby-and super degreasing shampoo and delicate, even if its foaming power is delicate.
Sucrose esters
Sucrose is a disaccharide formed by the union of two molecules - glucose and fructose - via a glycosidic bond. The surfactants in this class are also known as "sugar esters" or "sucrose esters".
These esters are obtained by reaction of trans-esterification of sucrose or fructose with fatty acids. The part of the molecule involved in this reaction is the group-CH2OH present in position 6 in glucose and fructose in position 5. The esters of sucrose have excellent capabilities of emulsifiers and detergents, but their activity is limited foaming. These products have a high interest on the outstanding natural and biodegradable.
Esters of fatty acids
As mentioned above, esters of fatty acids derived from a reaction between an alcohol and fatty acids, which in this case is the polyethylene glycol (PEG).These surfactants have emulsifying properties and are used in household detergents and industrial ones. They can be used as a mild detergent and thickeners (such as PEG-150-Distearate) and as pearling agents, given their limited solubility in water.
Glycol esters of glycerol or
The non-ionic esters of glycols (two-OH groups) or glycerol (three groups-OH) are obtained by a reaction between an acid and, respectively, alcohol or glycerin. To obtain a tenside of this type is essential that the molecule is present in a lipophilic tail (R) and a very bulky ester units as hydrophilic head.These surfactants have the characteristics of emollients, emulsifiers and water soluble.
Alcanolammidi
The alcanolammidi are obtained by a reaction of acylation of various alcanolammmine. While these non-ionic surfactants, are used primarily as supporters of foam and thickeners. The alcanolammidi are widely used in household cleaners. The most common are: monoethanolamine, or MEA alcanolammide which has only one group-CH2CH2OH; alcanolammide the DEA or diethanolamine, which has two-CH2CH2OH groups and finally monoisopropanolammina or MIPA, which has a molecule of isopropanol.
There are ethoxylated derivatives of alcanolammidi whose result is a product polyethoxylate, the only drawback is the high cost of production.
Analysis of some detergents and their ingredients
Now are examples of formulations containing surfactants. The purpose of this exercise is to analyze the composition and to classify the various surfactants.The ingredients are listed out of order so as to make the search and recognition more difficult but effective.
FORMULA 1: Shampoo
Ingredients: Sodium Laureth Sulfate, Cocamide DEA, fragrance, preservatives and water, sodium chloride, dyes, Cocamidopropyl betaine.
In this formulation we can identify 3 surfactants: the first on the list is sodium laureth sulfate (SLES), which is part of the anionic, Cocamide DEA is the second part of the non-ionic surfactants alcanolammidici and is an excellent thickener (in synergy with sodium chloride) and foam stabilizer. Finally, the third is the Cocamidopropyl betaine detergent that is part of amphoteric surfactants, which are mainly used to reduce the aggressiveness of anionic surfactants.
Formulation 2: CLEANER UNDERWEAR
Ingredients: Sodium Laureth Sulfate, Disodium Cocoamphodiacetate, Sodium Lauryl Glutamate, caprylyl / caprylate glucoside, Eucalyptol, Menthol, PEG-120 Methyl Glucose Diola, citric acid, water, dry holly, Disodium EDTA, PEG-18 Glyceryl Cocoate / oiled.
In this formulation we can identify the tenside SLES, which is anionic and amphoteric tenside, the Disodium Cocoamphodiacetate. The Sodium Lauryl Glutamate is an anionic surfactant derived from amino acids. The caprylyl / caprylate glucoside and PEG-120 Methyl Glucose Diola are non-ionic surfactants derived from glucose. The term Diola indicates that glucose is linked via ester bond to two molecules of oleic acid. PEG-120 with the prefix indicates the presence of un'etossilazione with an average number of 120 groups - (CH2CH2O) No Glyceryl Cocoate PEG-18 / oleate is also a non-ionic ethoxylate surfactant, in which case the glycerin has been esterified with fatty acids derived from coconut and oleic acid.
Formulation 3: FOAM CLEANER
Ingredients: Cocamidopropyl Betaine, Disodium Laureth Sulfosuccinate, Sodium Lauryl Sulfoacetate, Sodium Lauroyl Glutamate, SLS, Cocamidopropylamine Oxide, PEG-7Glyceryl Cocoate, Fragrance, Water, Disodium EDTA.
Cocamidopropyl betaine amphoteric surfactant is classified as in its structure because it is a betaine. The Disodium Laureth Sulfosuccinate, Sodium Lauryl the SLES and Sulfoacetate are anionic. The Sodium Lauroyl Glutamate is an anionic surfactant derived from amino acids. Finally, the Cocamidopropylamine oxide and PEG-7 Glyceryl Cocoate are non-ionic type surfactants, respectively, and non-ethoxylated ethoxylates.
Toothpaste
The toothpaste falls into the category of cosmetics used for cleansing the oral cavity.
The purpose of toothpaste is to keep as long as possible to the mouth and teeth sanitation, eliminating possible food debris accumulated during meals, preventing the onset of caries, halitosis, gingivitis and periodontitis. The formulations that can be used are:
• toothpaste;
• Liquid Toothpaste;
• Toothpaste dry;
• Gelled Dentifirici.
The toothpastes are made of abrasives, binders, wetting, sweeteners, foaming agents, preservatives, dyes, lubricants edaromatizzanti.
Toothpaste ingredients: abrasives
Abrasive substances are soluble salts that are not to be within the formulation.Usually, these substances are present in the toothpaste with a rate varying from 30 to 60%. The abrasive toothpaste formulated to allow you to remove plaque and food debris. The abrasive effect is conferred by the shape, size (including 15 and 20 M) and the hardness of the crystal. The effect should not be too strong because in the face of a greater whitening effect is the possibility of damaging the enamel from your teeth. The salts used are those derived from more calcium, aluminum, silicon and magnesium, such as Ca (PO 4) 2, CaHPO4, Ca2P2O7, CaSO4, Al2O3, SiO2, Al (OH) 3, Mg (OH) 2.
Toothpaste ingredients: a binder
The binders serve to hold together all the various components of the formulation, at the same time give the toothpaste a certain consistency and viscosity. In toothpaste binders most frequently used substances are cellulose, such as the 'idrossimetilcellulosa (HMC) and carboxymethylcellulose (CMC).These substances, when placed in water, swell and give the formulation of a certain viscosity.
Ingredients of toothpaste: humectant or humectants
In a toothpaste formulation, these substances are typically present at levels ranging from 20 to 30%. Humectants are substances ipolialcoli par excellence, such as glycerin, propylene glycol and sorbitol. These substances, by binding water present within the formulation through their hydroxyl groups - OH, do not involve the process of evaporation and dehydration of the product while keeping to a certain degree of humidity.
Ingredients of toothpaste: sweetening substance
The sweeteners are substances present in very low percentages in the formulations, which are around 0.1%. Sweetener is used as a substance laSACCARINA standards, but they can also be used acariogeni other sweeteners.
Ingredients of toothpaste: foaming substances
The foam in toothpaste has a precise function, which is to reach the offices of the buccal cavity where the toothbrush can not reach. For the formation of the foam are used anionicicome the alkyl sulphate surfactants, non-ionic ionicicome amides of fatty acids, amphoteric surfactants such as alchilamidopropilbetaine.
Toothpaste ingredients: preservative
The substances most used in toothpaste to prevent bacterial contamination or possible alterations, are: parabens, sodium benzoate, benzalkonium chloride, triclosan, benzyl alcohol, and sorbitol.
Ingredients of toothpaste: THE COLOURS
All of these substances - whose function is to give the formulation of a pleasing color - are included in Annex III of the law 713/86. Of course, the manufacturer must adhere strictly to the law, using only colors allowed in the formulation of products-cosmetics.
The dyes can be classified as:
• Water soluble, dissolved in an aqueous medium or in a similar;
• pigments, dissolved in an oily medium or a fat.
Ingredients of toothpaste: OIL SUBSTANCES
The lubricants used to facilitate the extrusion of the product from the tube. A lubricant that can be used is mineral oil.
Toothpaste ingredients: flavoring substances
Substances are very important, because they confer to prepare a saporegradevole. Flavourings for excellence are menthol and eucalyptus, but they can also be used cinnamon, thyme and anise.
Ingredients of toothpaste: AN EXAMPLE OF DENTIFIRCIO
Ingredients: Ca (PO 4) 2, Ca2P2O7, Al2O3, HMC, Glycerin, Sorbitol, Sodium Saccharin, SLS, peppermint, sodium p-hydroxybenzoate, Vaseline, pigments, water.
In this formulation there are abrasive salts with function. The HMC is a cellulose derivative which has the task of giving the formulation viscosity. Glycerine and sorbitol are wetting agents, and hold water in the toothpaste and avoid dehydration of the product. The saccharinate sodium is the salt of saccharin.SLS is a foaming anionic surfactant function. The oil of peppermint is the flavoring. The methyl p-hydroxybenzoate Sodium is also known as a preservative metylparaben. The Vaseline is inserted to facilitate the extrusion of toothpaste from a tube. The pigmenticonferiscono sought to prepare the color.The water completes the formulation.
Cosmetic emulsions
The first emulsion cosmetics dates back to Greek times, when the physicist Galen rose water mixed with olive oil and beeswax (Ceratum Galeni). The result was a cosmetic preparation in future times took the name of cream.
The use of emulsions on the skin has many advantages over other forms of cosmetic, because the action of aqueous and oily components is simultaneous and synergistic.
The components of both phases are deposited on the skin layer evenly.
In aqueous emulsions to external phase, the first substances to be deposited on the skin are water-soluble and fat-soluble ones later. The order of distribution is rather reversed when it comes to oily emulsion with external phase.
The lipid complex, in itself, would be distributed on the skin with much difficulty, but thanks to this formulation becomes easily spread in a thin layer. During the application of an emulsion on the skin lipids are mixed in it and participate in the phenomena of diffusion of substances used and applied. They are also very important for the reintegration of skin lipids that may be lacking, for example, for reasons of age, poor cleansing, sun exposure or skin changes.
From the perspective of chemical-physical formulations of the emulsions are complex. Consist of two substances that can not be mixed together, water and fat. You get energy by providing agitation and heat to win the interfacial tension between the two components. Through this process you get in the tiny droplets of a liquid: it puts the emulsifier interface and stabilizes emulsions by opposing the force which would separate the components.
Mainly, the emulsions can be classified into two categories:
1. WATER IN OIL EMULSIONS or A / O The internal phase is water or dispersed and the external phase is oil or dispersant;
2. Oil in water emulsion or O / A. The internal phase is oil or dispersed and the external phase is water or dispersant;
from these two possible leakage may lead to a wide range of products such as creams or milks, moisturizers, sunscreen formulations, etc..
The emulsions are obtained by rapid stirring at a temperature between 60 and 85 ° C, in order to have enough energy to melt all the necessary components, but not so high as to evaporate too much water during preparation.
Schematically, an emulsion O / W is represented by the oil droplets in an aqueous external environment. This emulsion is rendered stable by the addition of a surfactant to high hydrophilicity (HLB 8-16) which is to distribute the interface between two liquids. Of course you have the tail toward the lipophilic oil droplet and the hydrophilic head towards the external aqueous environment.
In the emulsion W / O droplets of water are in a dispersed in a dispersing oily.In this case, you add a tenside low hydrophilicity (HLB 2-6), which is to arrange the interface in an inverse emulsion to O / A.
RULE OF BANCROFT: the phase in which the surfactant or emulsifying agent is more soluble, it forms the external phase of the emulsion Therefore, if the surfactant is more soluble in water will get an emulsion O / W, but if the surfactant we are lipophilic emulsion W / O
The O / W emulsion can be made from a roughly 5% emulsifier system, a 20% lipid phase and a 75% aqueous phase. These percentages can derive various products such as low viscosity formulations - such as milks or lotions - but also more viscous formulations, such as facial creams. The emulsion O / W are the chemical and physical form best known and widespread, especially for the sensory characteristics and the easy applicability, also allow you to quickly get a moisturizing effect, with the advantage of a little greasy feeling and the cooling effect due to evaporation Part of the water present in the external phase.
The emulsion W / O can be composed of a 5-10% emulsifier system, by a 30-40% lipid phase and a 50-65% aqueous phase. The products that you can get are milk or cream. The water in oil emulsions provide a great emollient: the fact that it is water droplets immersed in oil means that, once spread on the skin, forming a continuous barrier, semi-occlusive disease, which prevents the evaporation of water from the deep layers of the skin.
Emulsifiers in cosmetics
The emulsifiers can be classified according to:
1. the electric charge;
2. the lipophilicity / hydrophilicity.
If they are ranked according to the electric charge of emulsifiers can be anionic, cationic, nonionic amphoteric and finally.
But if they are ranked according to the affinity for water or oil, we can have of lipophilic emulsifiers and hydrophilic nonionic surfactants, cationic, amphoteric and nonionic surfactants.
For both classifications, there is the presence of ethoxylated and ethoxylated products. Here are explained only emulsifiers classified according to their affinity for water or oil.
Lipophilic emulsifiers
Among the lipophilic emulsifiers ethoxylated nonionic surfactants the find and ethoxylates. According to the law of Bancroft these emulsifiers are to form the external phase of emulsion W / O
Among the emulsifiers are ethoxylated castor oil ethoxylates such as PEG-7 Hydrogenated Castor Oil. The latter is more suited to fluid emulsions.
Among the emulsifiers do not find the ethoxylated monoglycerides, sterols such as cholesterol, phytosterols, as well as sorbitan esters.
Hydrophilic emulsifiers
These are emulsifiers in stabilizing emulsions of type O / A (as opposed to those lipophilic). This category includes anionic, cationic, amphoteric and nonionic surfactants, so you can operate a distinction based on the electrostatic charge.
Among the anionic hydrophilic emulsifiers find the classic salts of fatty acids, the acilglutammati, protein fatty acid condensates (acylation derivatives) and alkyl sulphate. The anionic emulsifiers are characterized by well-efficacy than non-ionic, and because of their highly aggressive are used in lower doses and in combination with some other tenside to be able to mitigate or "cut". Many anionic hydrophilic emulsifiers are dispersible and soluble in water, and are almost always in combination with a lipophilic emulsifier. Examples of anionic emulsifiers are sodium stearate coupled to Glyceryl Stearate, stearoyl ilSodium Glutamate, Sodium Cetearyl Sulfate on.
Cationic surfactants are used as emulsifiers and conditioners primarily in formulations intended for treatment of hair, as they have high aggression to the skin. Among them the most common product is cetyl trimethyl ammonium chloride (Chloride Cetrimonium).
Among the amphoteric surfactants find lecithin and its hydrogenated derivative.Phosphatidylcholine or lecithin is derived from soy or egg, and is used as an emulsifier and as essentially functional. In fact, it has moisturizing and emollient properties, due to its excellent eudermicità. The derivative is more stable to oxidation than hydrogenated lecithin. If you go to observe the molecule can be seen that two of the hydroxyl groups of glycerol are esterified with a fatty acid, so you get the lipophilic tail. The third-OH group of glycerol is replaced with a phosphate group, which in turn is linked with choline. The phosphoric acid and choline group have formed the hydrophilic head.
The non-ionic emulsifiers, although not very effective, have the advantage of being insensitive to the pH of the formulation. Also in this category we can find products and ethoxylates. The most common products are ethoxylated fatty alcohols with PEG, PEG with fatty acids, the
monoglycerides, sorbitan esters. But those are not ethoxylated polyglycerol esters, sucrose esters, ethers and finally glucose.
Emulsions, the fat and oil
To complete the argument of the emulsions, it is important to mention and describe the fat used to produce the emulsion.
The fat phase in an emulsion used is composed of lipids. These are all those substances that are not soluble in water. From the chemical point of view, be regarded as lipids:
• paraffinic hydrocarbons with at least 10 carbon atoms;
• cycloparaffins;
• terpene hydrocarbons;
• linear polydimethylsiloxanes, cyclic and derivatives;
• glyceric esters (triglycerides, diglycerides);
• non-glyceric esters (oils and waxes);
• fatty alcohols fluids
• fatty acids.
From the list above are taken into account only certain lipids, such as hydrocarbons, esters and non-glyceric glyceric, fatty alcohols, and finally fluid fatty acids.
Hydrocarbons
Hydrocarbons are organic compounds containing only carbon and hydrogen elements. The carbon atoms are known to form the skeleton of the molecule, while the hydrogen project from the carbon chain.
These days were calculated about 133 thousand types of hydrocarbons.Depending on environmental conditions and molecular, such as pressure, temperature and molecular weight hydrocarbons may occur in the form of gases, liquids or waxes.
Despite the saturated hydrocarbons are highly reactive with oxygen, flammable, have a low chemical inertia. Precisely because of this characteristic are also called paraffins (from the Latin affinis Parum "unresponsive"). Much more reactive than saturated hydrocarbons are unsaturated, whose high reactivity is due to the presence of double or triple bonds along the carbon chain.
Hydrocarbons can be classified according to their chemical characteristics, so we have:
• HYDROCARBON FLUIDS. The two most common are the heavy and light mineral oil. The heavy fuel oil is quoted in many pharmacopoeias, highly purified and degrees available in various molecular weight. The INCI name is Paraffinum Liquidum in Europe, but the American INCI is Mineral Oil. Typically these products are apolar, odorless, colorless and inert.
• HYDROCARBON semisolid. Among the semi-solid hydrocarbons found petroleum jelly (Petrolatum INCI name), a complex mixture of hydrocarbons having carbon numbers above 25. The Vaseline is presented as a semisolid mass of yellow-white, no smell and does not react with other substances.
