Hair Coloring and Perming Techniques

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Questions and Answers

What are the two types of melanin responsible for hair color?

Eumelanin and pheomelanin.

List the three aims of hair coloring.

To cover grey hair, to change existing color, and to combine both aims.

What is the main oxidizing agent used in hair bleaching?

Hydrogen peroxide (H2O2).

Why should hair not be washed prior to bleaching?

Washing removes protective lipids that help reduce hair damage and scalp irritation. Signup and view all the answers

What role does ammonium hydroxide play in the bleaching process?

It acts as an alkalizer that causes cuticle swelling for faster access of the oxidizing agent. Signup and view all the answers

How does the temperature of the scalp affect the bleaching process?

Bleaching near the scalp is faster due to the higher temperature from proximity to human skin. Signup and view all the answers

What is the purpose of using acidic shampoos after bleaching?

They reduce protein damage to the hair. Signup and view all the answers

What is a common material used alongside hydrogen peroxide in modern bleaching products?

Persulfates. Signup and view all the answers

What percentage of disulfide bonds are broken during the hair perm reducing step?

20% Signup and view all the answers

What is the most common reducing agent used in hair perming?

Thioglycolic acid Signup and view all the answers

What role does H2O2 play in the hair perming process?

It serves as the oxidizing agent for neutralization. Signup and view all the answers

How long is the process time for applying thioglycolic acid during perming?

5-20 minutes Signup and view all the answers

Explain the purpose of the neutralization stage in hair perming.

To fix the new shape of the hair by forming new disulfide bonds. Signup and view all the answers

What is the aim of hair straightening or relaxing?

To reshape hair permanently. Signup and view all the answers

How often does regrowth require a new treatment during hair straightening?

Every 6 weeks. Signup and view all the answers

What is one key difference between hair perming and hair relaxing?

Perming creates curls while relaxing straightens hair. Signup and view all the answers

What is the primary chemical used in permanent hair colorants to oxidize dye precursors?

Hydrogen Peroxide (H2O2) is used to oxidize dye precursors. Signup and view all the answers

What is the pH range for demi-permanent and tone-on-tone hair colorants?

The pH range is typically between 9.8 to 10.3. Signup and view all the answers

How do semi-permanent hair colorants achieve penetration into the hair?

Semi-permanent dyes use small, intensely colored neutral dye molecules that penetrate the hair cortex. Signup and view all the answers

What distinguishes temporary hair colorants from other types?

Temporary hair colorants consist of large, intensely colored ionic dye molecules that reside only on the hair surface. Signup and view all the answers

What is the effect of using lead acetate in progressive hair colorants?

Lead acetate oxidizes to form dark colored metal-sulphides, gradually building up color with repetitive applications. Signup and view all the answers

What type of alkaliser is used in demi-permanent hair colorants?

Demi-permanent hair colorants use monoethanolamine or amino methyl propanol as alkalizers. Signup and view all the answers

In what year was p-phenylenediamine discovered, marking the birth of the synthetic hair dye industry?

p-phenylenediamine was discovered in 1883. Signup and view all the answers

Why is there a need for a positive dye list in the EU?

A positive dye list ensures minimal dermatological and toxicological effects from hair colorants. Signup and view all the answers

What is the primary characteristic of temporary hair dyes regarding their duration on the hair?

Temporary hair dyes last until the next shampoo. Signup and view all the answers

How do cationic dyes interact with hair compared to anionic dyes?

Cationic dyes are strongly attracted to hair, while anionic dyes lack this strong interaction. Signup and view all the answers

Why are large cationic molecules used in rinse-off products for hair coloring?

They have substantivity that allows subtle coloring effects while being easily rinsed off. Signup and view all the answers

What compounds are primarily involved in the reducing stage of hair perming?

Thioglycolic acid (TGA) and glycerol thioglycolate (GTG) are used in the reducing stage. Signup and view all the answers

How does the oxidation stage in hair perming utilize hydrogen peroxide?

Hydrogen peroxide (H2O2) is applied at acidic pH to facilitate the oxidation of hair after the reducing stage. Signup and view all the answers

What effect does bleaching have on the perming process?

Perming is less effective on bleached hair due to altered hair structure and chemistry. Signup and view all the answers

What is the significance of the low viscosity formulation for perming agents?

Low viscosity allows the active ingredients to soak into the hair effectively. Signup and view all the answers

What is the primary role of hydrogen peroxide in hair dyeing?

Hydrogen peroxide oxidizes primary intermediates to reactive intermediates and bleaches the hair for achieving lighter shades. Signup and view all the answers

How do high pH levels affect the hair during the dyeing process?

High pH levels cause swelling and cuticle lifting of the hair, allowing better penetration of dye precursor molecules. Signup and view all the answers

What internal stress do hair fibres undergo during the perming process?

Hair fibres experience internal stress due to the strain on -S-S- bonds when wound onto rollers. Signup and view all the answers

What undesirable effects does bleaching have on the hair?

Bleaching causes oxidation of disulfide bonds, increased hair hydrophilicity, and destabilization of the hair's cortex. Signup and view all the answers

What characterizes demi and semi-permanent hair dyes?

Demi and semi-permanent dyes are direct dyes that contain intrinsically colored molecules and do not undergo reactions. Signup and view all the answers

Why are color pairs used in hair dye formulations?

Color pairs help to achieve even color distribution between the roots and tips, reducing unevenness during wash fading. Signup and view all the answers

What is a key secondary product formed during the bleaching process?

The oxidation of melanin results in colorless products that do not provide pigmentation. Signup and view all the answers

How does the increase in hair hydrophilicity affect dye penetration?

Increased hydrophilicity enhances water swelling in the hair, facilitating greater dye penetration. Signup and view all the answers

What happens to the peptide bonds during the bleaching process?

Peptide bonds undergo hydrolysis, producing soluble protein hydrolysates that can wash away. Signup and view all the answers

What is the role of alkali in hair relaxing treatments?

Alkali, such as sodium or potassium hydroxide, breaks down the disulfide bonds in hair, allowing for straightening. Signup and view all the answers

What happens to S-S bonds during the hair relaxing process?

At least 30-40% of S-S bonds are affected, resulting in permanent bonding that loses the hair's elasticity. Signup and view all the answers

Why is protective cream applied to the scalp during hair relaxing?

Protective cream acts as a barrier to prevent irritation and damage to the scalp from the alkaline treatment. Signup and view all the answers

What is the main concern regarding the effectiveness of Guanidine Hydroxide in hair relaxing?

Guanidine Hydroxide is less effective compared to sodium-based relaxers but is milder on the hair and scalp. Signup and view all the answers

Describe the significance of thorough rinsing after applying the alkaline cream.

Thorough rinsing removes excess chemicals from the hair and scalp, reducing the risk of ongoing damage. Signup and view all the answers

What are 'lye relaxers' and how do they differ from non-lye relaxers?

'Lye relaxers' are sodium hydroxide-based products, while non-lye relaxers may contain potassium or lithium hydroxide. Signup and view all the answers

What are the anticipated effects of hair relaxing treatments on hair's physical properties?

Hair relaxing leads to protein chain damage, resulting in weakened and less elastic hair. Signup and view all the answers

What trend is influencing the current market for hair treatments?

There is a declining interest in drastic alterations like hair color or shape, with a focus on more gentle treatments. Signup and view all the answers

Study Notes

Specialist Haircare Products

The presentation is about specialist haircare products, specifically focusing on hair colouring, perming, and relaxing.
The presentation includes historical context, chemical processes, and practical application for hair treatments.
Various techniques and considerations are explored for different hair types and desired outcomes.

Hairdressing History

Images from the 1920s show hairdressing techniques at UAL.
This indicates the presentation covers historical developments in hairstyling and possibly touches on the evolution of haircare products.

Lesson Agenda

The agenda covers hair colouring.
It includes hair perming and relaxing, highlighting key differences.
It also covers an overview of hair fibre properties versus chemical alterations, showing how chemical treatments affect the hair structure.

Hair Colour

Hair colour is due to eumelanin and pheomelanin deposited during hair growth.
Hair greying is linked to cumulative oxidative damage, genetic factors, stress, and nutrition.
Studies show temporary or partial reversion is possible.

Hair Colouring

Hair colouring can aim to cover grey hair, change existing colour, or combine both.
Longevity of colour results varies depending on the type of hair colour product.
Common types and levels of lastingness for hair colour products are presented in a table.

Basics of Hair Bleaching

Commonly used bleaching materials include hydrogen peroxide (H2O2) and alkalisers like ammonium hydroxide.
Chemicals are mixed just before application to ensure effectiveness, and reduce irritation.
Recommendations for using and mixing bleaching agents are detailed, including thickening and avoiding scalp issues.

Hair Colour Lightening

Lightening is necessary for colouring.
Most permanent colourants involve some level of oxidation.
A table shows different levels of bleaching power associated with different hair colours.

Hair Colourants: Product Types and Modes of Action

Permanent hair dyes are a two-component system mixing just before use.
Alkaline (Ammonia) and Hydrogen Peroxide (H2O2) are used to oxidise dye precursors, resulting in large dye molecules trapped within hair.
Demi-permanent or tone-on-tone dyes use a different alkaliser(monoethanolamine or Amino methyl propanol) and lower concentrations of H2O2 to colour the hair, penetration is not as great as with permanents.
Semi-permanent dyes are intensely coloured molecules that penetrate the cortex of hair.
Temporary hair dyes are intrinsically coloured molecules that reside on the surface of hair.

Hair Colouring Summary

Hair dyeing can be dramatic or subtle.
Phenylenediamine was discovered in 1883, which marked the beginning of synthetic hair dye industry.
Currently, there is positive list of dyes and global scrutiny to ensure minimal dermatological and toxicological effects.

Oxidative Hair Dyes

Oxidative hair dyes use two components which are mixed before application.
Colourless dye precursor molecules penetrate the hair and are oxidised to form coloured polymeric dyes inside the hair.
Primary intermediates and couplers form dye molecules, producing a variety of colours.
These colours are typically wash-resistant and typically involve 2-5 primary intermediates and 2-5 couplers.

Chemistry of Permanent Hair Dyes

Permanent hair dyes involve primary intermediates (often p-diamines or p-aminophenols).
They are oxidised by hydrogen peroxide, creating reactive species that react with couplers to form dyes.
Hydrogen peroxide, ammonia, and ethanolamine are also commonly used ingredients.
Coupling agents (colour couplers) react with primary intermediates to form dyes.

Damage from Bleaching

The primary goal of bleaching is oxidation of melanin, but the products of this reaction may not be characterised.
Secondary effects (undesirable) are weakening of the hair.
Oxidation of disulfide bonds to cysteine acid is listed as one of the effects.

Demi and Semi-Permanent Hair Dyes: Direct Dyes

Direct dyes are intrinsically coloured molecules.
No chemical reactions take place during application.
These dyes provide intense vibrant colours, frequently used for mixing and matching various shades.
Formulated at pH 8.5-9.5 along with MEA to temporarily increases swelling of hair and allows dye penetration to be longer-lasting.
A cap may be used to increase effects of the dye.

Hair Fibre and the Dye Molecules

Micrographs illustrate the penetration and distribution of dyes within hair fibres.
Permanent dyes penetrate deeply into the hair cortex, visible in the micrograph images.
Semipermanent dyes are distributed more superficially, showing in the micrograph images.

Temporary Hair Dyes

Temporary hair dyes last one shampoo, and are high-intensity vibrant colours.
They do not transfer to clothes through rubbing.
Cationic dyes are highly attracted to the hair.
They are often used for temporary colouring or boosting colours after oxidative colouring.

Some Temporary Hair Dyes

Temporary hair dyes include large molecules that reside on hair surface and offer subtle colour effects.
Substantivity of the dye molecules allows them to be used in rinse-off products.
Types of temporary dyes mentioned are 'Basic' (cationic) and 'Acid' (anionic).

Hair Perming and Relaxing: Similarities and Differences

Hair perming and relaxing use similar chemical concepts.
Differences lie in their goals (change in shape vs. straightening).
Both involve chemical alterations which affect properties of hair fibre.

Chemistry of Hair Perming (Cold Waving)

Thioglycolic acid (TGA) and glycerol thioglycolate (GTG) are used in different pH to achieve loose or tighter waves.
High pH is needed to swell the cuticle, allowing precursor molecules to penetrate.
H2O2 (hydrogen peroxide) along with acid are used for oxidation to create more permanent curls.

Chemistry of Hair Perming

Hair fibres under stress from being wound onto rollers affect -S-S bonds.
This leads to disulfide bonds rearranging in a process called disulfide exchange.
Thioglycolic acid is a common reducing agent, while H2O2 is a common oxidising agent.,
20% of disulfide bonds are broken to achieve new bonds.

Hair Perming Technique

The hair is shampooed and towel-dried.
Strands are applied to rollers under tension.
The process and time are dependent on the specific hair type.
Reducing agent is applied, followed by neutralisation.

Hair Lightening: Process, Hair Damage and Repair

Hair lightening is a chemical process.
Considerations should include the damage caused by lightening.
Repair methods should be included.

Overview of Hair Fibre Properties vs Chemical Alterations

Hair fibre properties are important to consider when using chemical alterations like lightening, perming, and relaxing.
Chemical treatments alter the hair's structure.

Hair Straightening (Relaxing)

Hair straightening is a permanent technique for changing hair shape.
Hair that has been relaxed will need to be retreatment after about 6 weeks.

Oxidation of Disulfide Bonds

At least 30-40% of the S-S bonds in the hair are affected when performing a straight hair style.
A chemical reaction takes place to create a permanent bond, for instance the S-CH2 bond is created and called lanthionine.
S-S bonds are not reformed, leading to loss of elasticity.
The hair looses structure, as damage to the protein chains may occur and result in weakening of the hair.

Chemistry of Hair Relaxing

Common alkaline agents (NaOH, KOH, LiOH) are used in thick emulsions for relaxing hair, and to avoid spreading to the scalp.
Guanidine hydroxide is a milder alternative but less effective.
The specific formulations may be referred to as "lye relaxers" but may also use alternative alkaline agents.

Hair Relaxing Technique

Protective cream is applied to the scalp before the relaxing cream.
Applying the relaxing cream to the hair strands should be done without stretching.
Thorough rinsing both hair and scalp is required.
A neutralising shampoo may be used to neutralize the alkaline reaction.

Summary of Chemical Treatments

Fewer consumers are interested in altering hair colour and style.
Less aggressive chemical treatments are developing in response.

Scenario 1, 2, 3

Scenarios outlining specific hair conditions and desired outcomes to evaluate treatment options for changing hair style.
These scenarios allow for evaluating the potential chemical treatments needed and predicting the potential damage from the procedure.

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Description

This quiz explores the science behind hair coloring and perming techniques. It covers key concepts including melanin types, hair bleaching agents, and the perming process. Test your knowledge on the chemistry involved in achieving vibrant hair colors and styles.