chemistry for cosmetics dr lida schoen amsterdam
TRANSCRIPT
Lida Schoen Chemistry of hair and skin products 3
‘‘Dirt’ on the skinDirt’ on the skin‘‘Dirt’ on the skinDirt’ on the skin
• water soluble (sweat);
• oil soluble (sebum, grease);
• non soluble (sand, skin flakes).
Rubbing with water and soap can remove all three.
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Cleaning the skin: water and soapCleaning the skin: water and soapCleaning the skin: water and soapCleaning the skin: water and soap
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Washing dirt from textilesWashing dirt from textilesWashing dirt from textilesWashing dirt from textiles
with water and soap
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‘‘Cosmetic’ cleanersCosmetic’ cleaners‘‘Cosmetic’ cleanersCosmetic’ cleaners
Showergel (=shampoo)
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‘‘Cosmetic’ emulsionCosmetic’ emulsion‘‘Cosmetic’ emulsionCosmetic’ emulsion
• Water• Oil• Emulsifier• Additions
– Perfume– Colour
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Emulsion: microEmulsion: microEmulsion: microEmulsion: micro
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Emulsion: macroEmulsion: macroEmulsion: macroEmulsion: macro
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CreamCream
• 2-3% emulsifier + thickener (for stabilisation)• 10% oil like
– mineral like paraffin (cheap, doesn’t deteriorate)– vegetable like avocado (what’s good to eat …), – animal like mink (snob appeal)
• Water• Perfume• Additive, like
– dihydroxyacetone (artificial tanning)– herbals
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Hair under microscopeHair under microscopeHair under microscopeHair under microscope
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Chemistry: keratinChemistry: keratin
• Hydrogen bridges
• Ion-ion (salt) bonds
• Disulfide (sulpher) bonds
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Melanin in cortexMelanin in cortex
Eumelanin• black-brown;• large molecules;• easy to light up.
Pheomelanin• yellow-red;• smaller molecules;• difficult to light up.
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Hair cleaning: shampooHair cleaning: shampooHair cleaning: shampooHair cleaning: shampoo
Detergent: sodium lauryl (=C12) ether sulphate:
• cheap• skin friendly• good foam• easy to thicken (with NaCl)
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Ether sulfatesEther sulfatesEther sulfatesEther sulfates
• Vegetable oil, after hydrolysation and reduction, ethoxylation with ethylene oxide
• Alkyl alcohol esterified with sulphuric acid: CH3-(CH2)10-CH2(OCH2CH2)n)OSO3
- Na+
with 1<n<4
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Thickener: electrolyteThickener: electrolyteThickener: electrolyteThickener: electrolyte
• detergent in water: micelles
• NaCl (3-4%)
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Conditioner in the past: egg yolkConditioner in the past: egg yolkConditioner in the past: egg yolkConditioner in the past: egg yolkEgg shampoo:• Egg yolk: lecithin
Conditioner today: man madeConditioner today: man made•quat = quaternary ammonium compound•silicone
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Hair gel at schoolHair gel at school
Carbomer (brand name in Europe): neutralised cross linked polymer of acrylic (propene) acid
CH2=CH-COO-Na+
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Bleaching (1)Bleaching (1)
• Decomposition of melanin by oxidation in alkaline (ammonia) environment;
• carboxylated derivatives soluble at higher pH’s.
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• Bleaching powder: persulphate:(O3S-O-O-SO3)2-
2 Na2S2O8 -> 2 Na2S2O7 + O2
• Hydrogen peroxide,(max. 12%, pH = 4), optimum melanin bleaching at pH pKa (11,5) of the peroxide-anion.
• In practice: pH = 10. H2O2(aq) 12% not stable at pH = 10.
Bleaching (2)Bleaching (2)
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Types of haTypes of haiir r cocolloouurriinngg
– permanent
– semi-permanent– temporarily
• OxidativeOxidative
• DirectDirect
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HaHaiir r cocolloouurriinngg productsproducts
• Natural• Metal• Permanent (synthetic dyes)• Semi-permanent (natural en synthetic dyes)• Temporarily (synthetic dyes)
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Semi-permanent haSemi-permanent haiir r cocolloouurriinngg
• in and under cuticle• 4-6 washings• till 30% grey covering
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Metal ‘dyes’Metal ‘dyes’Metal ‘dyes’Metal ‘dyes’
• Acetates or sulphates of: lead, silver, iron, copper, cobalt, bismuth, manganese, zinc
• Sulphide bonds with sulphur from keratin
• Toxic properties!
• Sensitive to oxidation
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Permanent haPermanent haiir r cocolloouurriinnggPermanent haPermanent haiir r cocolloouurriinngg
• Oxidative dyes: ‘development’ with hydrogen peroxide
• Not washable• Till 100% grey covering
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Developers and couplersDevelopers and couplersDevelopers and couplersDevelopers and couplers
NH2
NH2
NH2
NH2
CH3
NH2
OH
NH2
OH
CH3
NH2
OH
NH2
NH2
OH
OH
NH2
OH
CH3
Ontwikkelaars
Koppelaars
p-Fenyleendiamine Tolueen-2,5-diamine p-Aminofenol 4-Amino-m-cresol
m-Fenyleendiamine m-Aminofenol p-Amino-o-cresol Resorcinol
= developers
= couplers
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Examples of couplingsExamples of couplingsExamples of couplingsExamples of couplings
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Summary chemical ‘trick’Summary chemical ‘trick’Summary chemical ‘trick’Summary chemical ‘trick’
• Mix two (or more) kinds of small molecules;• cover hair with mixture;• small molecules intrude the hair cortex (higher
pH will help to open cuticula);• inside the cortex small molecules react to much
bigger molecules;• The big molecules are captured in the cortex,
they can’t leave: permanent hair dye
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Bath saltsBath saltsBath saltsBath salts
1. Salt1. kitchen salt: NaCl (cheap, crystals)
2. soda : Na2CO3 (softener)
3. bicarbonate: NaHCO3 (solubility)
4. phosphate: Na3PO4 (complexer)
2. Perfume
3. Colour (water soluble food colour)
4. Extra (chamomile, herbals)
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Perfume (1)Perfume (1)Perfume (1)Perfume (1)
• Natural (past) and synthetic (aldehydes, ketones, esters)
• Mixture of 3 groups ‘notes’:– Top;– Middle;– Base.
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citrusgreenfruity
lime, lemon ,mandarin, orange, grass, apple,pineapple, cassis, raspberry, peach
TOP
MIDDLE
BASE
floral
woodypowdery
jasmin, rose, violet,muguet
sandalwood,cedarwood,ambery, musky,vanilla, sweet hay
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‘‘Our’ Chanel AllureOur’ Chanel Allure
• citrus: 15 drops (top)
• lily of the valley: 8 drops (top/ middle)
• rose: 2 drops (middle)
• jasmin: 10 drops (middle)
• floral bouquet: 5 drops (middle)
• sensual: 10 drops (base)
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DilutionDilution
• With min 70% alcohol
• Denaturated (tax reasons) with bergamot (citrus) or DEP (di-ethylphtalate)
• Perfume: 20% oils
• Eau de Toilette: 5% oils
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Allure – Fragrance DescriptionAllure – Fragrance DescriptionAllure – Fragrance DescriptionAllure – Fragrance Description
From the Chanel website:• The concept of Allure was Coco Chanel’s ideal: an
innocent seduction without artifice, an unforgettable elegance transcending words and conventions.
• Fragrance family: floral, fresh, oriental. A faceted fragrance that mixes notes of the Orient with abstract flowers.
• A simple jewel that combines 6 complex facets. In Allure, you’ll find bergamot, mandarin, water lily & magnolia, jasmine and may roses, vetiver and finally, the velvety sensuality of vanilla.