Hair Bleaches

Neutralizing Lotion. The principal active ingredient of cold wave neutralizers is usually an oxidizing agent. The most popular is hydrogen peroxide [7722-84-1J, employed at a concentration of 1—2% it continues to find widespread use. Aqueous solutions of sodium bromate [7789-38-0] at a concentration of 10—20% occasionally are used and are technically preferred over the peroxide formulations because of excellent stabiUty and absence of hair bleaching. Neutralizing powders appear to be on the decline but formulations stiU in use consist of sodium perborate [7632-04-4] combined with hexametaphosphates to improve solubiUty in hard water. 

Hair bleaching removes the pigment melanin from the hair shaft by oxidative destmction. Alkaline hydrogen peroxide is the agent of choice. 

World production expressed as 100% H2O2 approached 1.9 million tonnes in 1994 of which half was in Europe and one-fifth in the USA. The earliest and still the largest industrial use for H2O2 is as a bleach for textiles, paper pulp, straw, leather, oils and fats, etc. Domestic use as a hair bleach and a mild disinfectant has diminished somewhat. Hydrogen peroxide is also extensively used to manufacture chemicals, notably sodium perborate (p. 206) and percarbonate, which are major constituents of most domestic detergents at least in the UK and Europe. Normal formulations include 15-25% of such peroxoacid salts, though the practice is much less widespread in the USA, and the concentrations, when included at all, are usually less than 10%. 

Haar-balg. m. hair follicle. -balgdrUse. /. sebaceous gland. -beize, /. depilatory, -bleiche, /. hair bleaching, -blutgefass, n. (Anat.) capillary, -draht, m. extremely thin wire, capillary wire, -driise, /. sebaceous gland. 

Ultraviolet light from the sun is the most common hair-bleaching agent. Lemon juice is sometimes added to speed up the process of reducing the double bonds in hair pigments to single bonds. 

However, the most famous hair bleach is hydrogen peroxide. Unlike sunlight and lemon juice, peroxide is an oxidizing bleach, and its effects are less easily undone. 

Hydrogen peroxide is normally sold for industrial use as a 30% by mass aqueous solution. When used as a hair bleach (as a 6% solution), it acts by oxidizing the pigments in the hair. A 3 % H2Q2 aqueous solution is used as a mild antiseptic in the home. Contact with blood catalyzes its disproportionation into water and oxygen gas, which cleanses the wound ... 

She walks home flanked by Jimi and Bliss. Feels so far away. The foreigner accompanied by friends of a friend, the acquaintance taken care of. Jimi s hair bleached, traffic s red, Bliss s blue. Jimi jokes they are a walking tricolour. They stop at 32 around the corner. 

Ascorbic acid and derivatives are cited as potential ingredients in cosmetic formulations (876-879). Specific uses involve cosmetic compositions for thermal dispensing (880), dentifrice tablets (881), bath preparations (882), deodorants and mouthwashes (883-886), skin preparations such as skin lightening preparations (887) or protective creams (888-890). The more active areas have been hair and scalp preparations (891,892), hair setting compositions (893), hair bleaching programs (894, 895), and hair dyeing preparations (896, 897, 898). 

Hairdressers have higher rates of asthma than the general public. They are constantly exposed to persulfates in hair bleaches (hydrophiles) and hair sprays (mixtures of lipophiles and hydrophiles) J55 ... 

Problem Hydrogen peroxide is a powerful oxidizing agent used in concentrated solution in rocket fuels and in dilute solution as a hair bleach. An aqueous solution of H2O2 is 30.0% by mass and has a density of 1.11 g/mL. Calculate its... 

To summarize, sulfonic acid is the principal established end product of the oxidative cleavage of the disulhde bond from the chemical bleaching of human hair with current hair bleach products [3,9]. The mercaptan content of bleached hair is lower than that of unbleached hair [4], The intermediate oxidation products of cystine (i.e., the disulhde monoxide, dioxide, trioxide, and tetroxide) do not exist as signihcant end products of hair bleaching using today s commercial bleach products [3,6,9]. Nevertheless, evidence has been presented demonstrating low levels of cystine oxides in bleached hair [2],... 

The formation of lanthionyl residues in alkaline media is described in Chapter 3. Note that if lanthionine is formed during hair bleaching, its sulfoxide and sulfone are also possible oxidation products. 

The primary safety concerns with hair bleaches, as with most hair care products, arise from misuse or failure to comply with the usage instructions. Skin irritation, hair breakage, oral toxicity, sensitization, and scarring alopecia either have been reported [72] from use (misuse) of hair bleaches or are mentioned on the warning labels of these products. 

Bergfeld [72] has reviewed adverse effects of hair cosmetics recorded at the Cleveland Clinic Dermatology Department over a 10-year period. Effects attributed to hair bleaches were simple skin irritation and hair breakage. However, Bergfeld reported neither sensitization reactions nor complex toxic symptoms for hair bleaches. 

The condition of the hair also affects the uptake and the diffusion of creme rinse and shampoo ingredients. A rule of thumb is that diffusion is faster into altered or damaged hair than into unaltered hair. Bleaching also lowers both the isoelectric and the isoionic points of hair, thereby attracting more cationic surfactant to the hair. Thus, the use of bridging agents is even more important to the adsorption to bleached hair than to chemically unaltered hair. 

Most of the studies with polymer JR employed bleached hair. Bleached hair has a higher concentration of negative sites at and near the fiber surface to attract and bind cations and is more porous than chemically unaltered hair. As one might predict, uptake of polymer JR onto unaltered hair was an order of magnitude lower than for bleached hair [25]. 

We have determined the density of human hair in solutions of benzene-carbon tetrachloride by the method of Abbott and Goodings [86]. The density of chemically unaltered hair at 60% RH varied from 1.320 to 1.327, depending on lot (dark brown European hair from DeMeo Bros., New York, and three samples taken from heads of volunteers). The density of our wool control was 1.320, identical with one lot of hair. Permanent waving did not change the density of hair. Bleaching (approximately 25% disulfide rupture) increased it, but only by 0.45%). 

Robbins and Reich [3] have described studies relating quantitative combing behavior to the single-hber properties of curvature, friction, stiffness, and diameter for straight, wavy, and kinky hair, aU treated with a shampoo detergent (sodium lauryl sulfate), a long-chain quaternary ammonium compound (stearalkonium chloride), a commercial pomade (from mineral oil and petrolatum), and a hair bleach (peroxide/persulfate system). 

Permanent waves and hair bleaches are both known to increase hair body, although the mechanisms of action of these products are different. Permanent waving increases hair body by increasing both hber curvature and hber friction [122], Bleaching hair does not increase hair hber curvature, but it can increase interhber friction substantially [122,123], and both of these effects are primary factors that increase hair body (see Table 8-29). 

D. Hydrogen peroxide tor household use is available in 3-5% solutions and it causes only mild throat and gastric irritation with ingestion of less than 1 oz. Concentrations above 10% are found in some hair-bleaching solutions and are potentially corrosive. Most reported deaths have been associated with ingestion of undiluted 35% hydrogen peroxide, sold in some health food stores as hyperoxygen therapy. ... 

---