Personal Care Products

Chem 1020, Ron Robertson, Chemistry Dept.

Detergents

Soaps precipitate with hard water ions calcium, iron and magnesium. Detergents are soap-like molecules which do not tend to from precipitates. A typical syndet molecule has a water soluble sodium sulfonate (-SO₃ Na) end and an oil-soluble hydrocarbon group.

A. Types of Detergents

• Anionic - negatively charged polar headCationic - positively charged polar head
• Nonionic - uncharged polar head

B. Components of laundry detergents

1. Surfactant - the detergent itself

• Laundry detergents use anionic surfactants
• Automatic dishwashers use nonionics
• Fabric softeners use cationic sufactants

2. Builders - protect the cleaning efficiency of surfactant by sequestration, precipitation, or ion exchange

• Phosphates and citrates sequester Ca, Fe, Mg ions
• Carbonates precipitate these ions
• Aluminosilicates protect by ion exchange

3. Antiredeposition agents - prevent soil from settling back on fabrics

4. Fluorescent whitening agents - convert UV to visible blue

5. Corrosion inhibitor - forms film around metal parts, protection from corrosive effects of water

6. Processing aid - prevent caking, promote flow properties

7. Fragrances

8. Oxygen bleach

9. Borax - helps maintain alkalinity, aids detergent action

10. Enzymes - break down soils and stains by biological action

Hair Care

A. Hair

• 1. Root
• 2. Shaft - keratin (fibrous protein)
• 3. Sebum secreted as a protective film and composed of fats, cholesterol and inorganic salts

B. Shampoo

a detergent solution with other ingredients added used to remove dirt and excess sebum from the hair

1. Detergent (sodium lauryl sulfate also called sodium dodecyl sulfate)

2. Acidifiers -to neutralize the basicity of detergent (Hair protein decomposes in extreme acid or base)

a. citric acid

b. phosphoric acid

3. Foam stabilizer - makes rinsing easier

a. lauramide diethylamine

b. cocamide MEA

C. Conditioner

1. mineral oil, lanolin, aloe vera, jojoba oil, dimethicone - added to replace sebum

2. humectant - attracts water, reduces static and makes hair more pliable

glycerin, propylene glycol, sorbitol, ammonium xylene sulfonate

3. protein fragments - fill in the cracks and dents

animal hides and hoofs

4. substituted ammonium salts - counteract static electricity that builds up in hair; charged end of salt sticks to the hair and the fatty tail sticks out and helps combing

tricetylammonium chloride

5. Thickener - adds in combing

xanthan gum and NaCl, cetyl alcohol

D. Dandruff - flaking of dead skin cells

• 1. zinc pyrithione - slows flaking of cells
• 2. salicyclic acid - brakes flakes into small pieces

E. Preservative - retards bacterial growth

• methylchloroisothiazolinone and methylisothiazolinone

F. Emulsifier - ingredients stay mixed

• glycol distearate

G. Opacifier - makes solution opaque

"The secret of the shampoo conditioner package is that the conditioner stays inactive until rinsing."

Sunscreens

A. 600,000 people are diagnosed each year with skin cancer (1991)

B. Protection needed for

C. Rating of sunscreens is in SPF (sunscreen protection factor) numbers.

D. Active ingredients

"Regular use of an SPF 15 sunscreen between the ages of 1 and 18 will reduce the lifetime risk of nonmelanoma skin cancer by roughly 4/5"

Mouthwashes

A. Background

B. Causes of bad breath

C. Active Ingredients

D. Other ingredients

Toothpaste

A. Tooth enamel

• Composed of a calcium phosphate compound
• Ca10(PO4)6(OH)2 Û 10Ca+2 + 6PO4-3 + 2OH-
• Acids react with the OH- to promote demineralization.

B. Plaque

C. Tartar

D. Functions of toothpaste

E. Ingredients of toothpaste

Ingredients of toothpastes (continued)

Cosmetics

A. Definition - a chemical preparation intended to be rubbed, poured, sprinkled, or sprayed on the human body to cleanse, beautify, promote attractiveness or alter appearance

B. Deodorants and antiperspirants

Sweat composition differs by heredity and diet but an average would be 99% water, 0.5% salt, small amounts of urea, uric acid, glucose, lactic acid, amino acids and fatty acids. Bacterial action causes "body odor"

Deodorants kill odor-causing bacteria, may also contain fragrances

• benzethonium chloride
• zinc phenosulfonate

other zinc compounds like zinc peroxide remove odors by oxidizing the amines an fatty acids

Antiperspirants stop or retard the operation of sweat glands and lower the amount of perspiration

• aluminum chlorhydrates Al₂(OH)₅Cl
  The aluminum ion is an astringent - a chemical species that acts by constricting the opening of sweat glands

C. Skin Care Products

1. Moisture content of epidermal keratin (dead skin cells) is about 10%. pH is about 4

2. Sebum from oil glands helps to prevent moisture loss.

3. Emollients prevent moisture loss through the formation of a waterproof coating.

• lanolin (grease from wool)
• avocado, soybean, safflower oils

4. Creams and lotions are emulsions (mostly oil in water but some are water in oil) of emollients and humectants (chemicals that attract water)

• mineral oil - emollient
• stearic acid - emollient
• sorbitol - humectant
• propylene glycol - humectant
• petrolatum - emollient
  

5. Hyaluronic acid supposedly is the moisture binding chemical in infant’s skin; retinoic acid is said to reduce wrinkle formation

D. Lipstick

Common components

• dye (dibromofluorescein {yellow/red} and tetrabromofluorescein {purple}) with a metal ion (iron, nickel or cobalt) to form a "lake"
  
  Aside: a "lake" is a coloring agent made of an organic dye adhering to an inorganic substance called a mordant.
• Castor oil and alkanes to dissolve the dye
• Lanolin as an emollient
• Waxes to cause stiffness
• Perfume

E. Perfumes, Colognes and Aftershave

A cologne is a dilute perfume

Perfumes

• top note - most volatile - extracts from crushed flowers, citrus oils
• middle note - less volatile - extracts from flowers such as rose, lily, jasmine
• end note - resins of waxy polymers derived from wood, musk, amber, balsam - ties top and middle notes together and makes scent less sweet, also functions as a sex attractant {unquantified in humans}
• 75 to 90% ethanol

Seven kinds of odors have been identified to match the seven types of olfactory receptors in the nose (camphorous, musky, floral, pepperminty, ethereal, pungent, putrid)

Aftershave

• chemical formulation designed to refresh the skin and smooth minor irritations
• omposition is about 40 to 60% alcohol, perfume, menthol (0.2%) for a cooling effect, small amounts of weak acids to restore skin pH after shaving with basic soap, aluminum or zinc astringent, and emollient such as glycerin or sorbital.
  Aside: Menthol is a differential anesthetic which anesthetizes most skin sensations except cold. It is widely used as an antipruritic (anti-itch)