Lipsticks
Contents
Cosmetics for face
Cold cream, vanishing cream,
cleansing creams, face powders, de pigmenting agents, sunscreen products,
powders, de pigmenting agents, sunscreen products, rouges and facial blushes,
lipsticks, lip salves, lip jelly, lip liner, lip gloss
Learning objectives
At the end of this lecture, the student will be able to:
•Explain the essential properties
of lipsticks
•List the ingredients of lipsticks
with their uses
•List the ingredients of lipsticks
with their uses
•Explain the evaluation of
lipsticks
Lipstick
• Lipstick may be defined as
dispersion of the colouring matter in a base consisting of a suitable blend of
oils, fats and waxes with suitable perfumes and flavors, moulded in form of
sticks to impart attractive gloss and colour, when applied on lips
• A lipstick, consists of a wedge-
or 'bullet'-shaped stick that is moulded hot and then cooled before being
placed into a small plastic cup or godet, which is held in a plastic or metal
case.
• The godet can be moved up and down inside the case by a screw or push action.
• Typically weighing 5-6 g, lipsticks are presented in this specialized type of container, which is cylindrical and specifically designed to aid application whilst protecting the stick
Requirements
• It should efficiently cover lips
with colour and impart a gloss which would last long
• It should not be gritty
• The stick should not dry
• It should be safe and
non-irritating
• It should adhere well to the skin
of the lips and, during wear, the colour should remain the same and not smear
or run
• During application the product
must be smooth, but not greasy
• Should not transfer from the lips
to other surfaces such as cups (or shirt collars), skin
• The stick should be strong enough
so that it does not break when force is applied; for example during application
• However, too rigid a stick will
be difficult to apply and would pull at the skin
• The stick should be free of
blemishes and airholes or pinholes
• The properties of the stick
should remain consistent during its life and it is important that with time the
formulation remains consistent and that particles of wax or oil should not form
on the surface, a property called 'sweating‘
• These products are regularly
carried around by the user and, as such, can be subjected to a variety of
temperatures.
• The stick should not be affected
by these changes of temperature and should retain its applications
characteristics at all times
Formulation
To consider the formulation of
lipsticks the basic raw materials are conveniently classified as follows:
1. Wax mixture
2. Oil mixture
2. Oil mixture
3. Bromo mixture
4. Colors
5. Preservatives and other
additives
Wax and oils:
• Best results are obtained by
using a mixture of waxes of different melting points and adjusting the final
melting point of the stick by adding a sufficient quantity of a high melting
point wax.
• Formulation which contain a high
concentration of a single high melting point wax should be avoided.
1. White Beeswax:
• A useful material to bind oils
and higher melting point waxes.
• The molten wax shrinks slightly
on cooling.
• Higher concentrations give a dull
waxy appearance and cause the stick to crumble during use
2. Ozokerite wax:
• Sticks containing more than 10%
Ozokerite tend to crumble during application
3. Candelilla wax:
• Gives a smooth and glossy
appearance to a lipstick if used at a slightly higher dosage concentration than
the proportion of beeswax
4. Paraffin wax:
• Show strong oil adsorption
properties
5. Cetyl alcohol:
• Binding agent between polar and
non-polar ingredients
6. Lanolin:
• Offer adhesion due to its
plasticizing as well as luster
7. Isopropyl lanolate:
• Disperse pigments well and has
convenient fusing properties to other ingredients
8. Cetyl lactate & myristyl lactate:
• Has a wax like consistency at
room temperature but melts on contact with the skin, giving the product a soft
effect
9. Castor oil:
• Is used in nearly all lipstick
preparation because of its property as a wetting agent for pigments
• It has a thick consistency which
provides stability
10. Paraffin oil:
• Serve as lubricant for
application and also adds lustre
Color system
Permitted colors must be used.
• The color is painted to the lips
in 2 ways:
1. By staining the skin with staining dyes.
• These are dye stuff in solution
capable of penetration the outer surface of the lips e.g. acid eosin, and other
halogenated derivatives of fluorescein known as (bromoacids).
Disadvantage:
• Difficulty of uniform dispersion
of these dye in the lipstick mass which resulting in shade variation
• So Amine salts of bromo acid
dyes, dissolve in a mixture of waxes and oils can be more uniformly dispersed
2. By covering the lips with a colored layer:
• The color is produced by
insoluble dyes and pigments, which make the film more opaque
• Both inorganic, organic pigments
& metallic lakes are used
Titanium dioxide:
• The most effective white pigment
used to obtain pink shades and opaque film on the lips
• Protecting them from the aging
effect of the sun
Metallic Lakes:
• Ca, Barium and Aluminum lakes of
many D&C color.
• A mix of staining dyes, pigments
and Tio2 (Titanium dioxide) is usually used in lip stick preparation
Formula- Lipstick
Carnauba wax 10%
Bees wax
15
Lanolin
5
Cetyl alcohol 5
Castor oil 65
Industrial Manufacture of Lipsticks
1. The 1st stage of
manufacture is the formation of the wax base
2. The oil is heated in the
process vessel to 175 - 185˚F (80 - 85˚C)
3. The waxes are melted
separately in a hemispherical jacketed vessel (often called a “kettle”)
typically fitted with an anchor stirrer/scraper
- Part of the oil may be added
to the kettle to aid the process
4. The wax phase is added to
the oil phase
• High shear mixers should not be used as they introduce air into the
product which is difficult to remove and can cause problems later when moulding
and flaming the finished bullets
Industrial Manufacture of Lipsticks
5. Pigments are selected for a
particular shade by carrying out a series of mixing trials
6. Dry powder pigments are
never added into a lipstick as they are very difficult to disperse uniformly.
Each pigment is first milled into a paste in some of the castor oil, typically
in a ratio of 1:3
7. The pigment should be
stirred into the castor oil and then left to stand, preferably for several
hours or overnight, and then the whole mixture is passed through a triple
roller mill, colloid mill or ball mill to grind the pigments into the castor
oil completely
8. After the pigment mass is
ground and mixed, it is added to the hot wax mass until a uniform color and
consistency is obtained
9. The molten lipstick mass is
then run out of the vessel via the tap into the pre-warmed and lubricated
moulds which are filled to the top to allow for shrinkage of the mass on
cooling
10. The filled moulds are then
placed either on a cooling table or into a large fridge/freezer to set
11. When the mass has set
completely the mould is removed from the cooling area, the surface lipstick is
scraped away and can be recycled
12. The mould is then opened
up and the lipstick bullets carefully removed and either transferred straight
into the lipstick cases or stored in trays until required for finishing
13. Once filled into the
holders, the sticks may be “flamed” to produce a glossy finish to the surface
and to remove any imperfections
• Flaming is an intricate procedure if carried out by hand and needs
plenty of practice to achieve the required finish without melting the bullet
• The moulded lipstick is passed through a flame whilst being rotated
• On a larger scale the holders can be placed on a conveyor belt and are
flamed whilst spinning past in front of a flame or hot-air jet.
• Tip shapes: The three shapes
common to early lipsticks – chisel, bullnose and bullet – were added to over
the years and now include exotic forms going by names such as sculptured,
blunt, gothic, fishtail, teardrop, moondrop, contoured, bullet-wedge,
moondrop-wedge and sculptured-teardrop.
Variations in manufacturing
procedure
• Split moulding many lipsticks is a time-consuming, wasteful and labour
intensive method of manufacture
• It also produces poor-quality sticks in general with many surface
imperfections
• Most modern lipsticks are produced on automatic lipstick machines
• One of the most common automatic machines consists of a table of moulds
which rotates through various heating and cooling chambers
• The warm moulds are first lubricated by spraying in a small amount of
oil, usually a low-viscosity silicone fluid
• They then pass under the filling head where the molten lipstick is
injected into them
• As they move round the table they are cooled by refrigerated
compartments and finally ejected out of the moulds by a small jet of compressed
air straight into the cases
• The full holders are then placed onto a conveyor belt and passed
through a tunnel; while spinning they pass in front of jets of hot air which
'flame' the surface to give the required glossy finish
• The next stage of the belt then twists down the holder to allow operators
to put the caps in place
• The labels are then applied to the base, again automatically, and the
completed lipsticks stored until required for dispatch, or shrink sleeved and
placed into display cases for the shops
Evaluation
• Quality control procedures are strict since the product must meet USFDA
standards
• Lipstick is a cosmetic which is ingested and because of this there are
strict controls on the raw materials and the manufacturing procedures
• Lipstick is mixed and processed in a controlled environment so it will
be free of contamination
• Incoming material is tested to ensure that it meets required
specifications
• Samples of every batch produced are saved and stored at room
temperature for the life of the product (and often beyond that) to maintain a
control on the batch
• As noted above, appearance of lipstick as a final product is very
important
• For this reason everyone involved in the manufacture becomes an
inspector, and non-standard product is either reworked or scrapped
• Final inspection of every tube is performed by the consumer, and if not
satisfactory, will be rejected at the retail level
• Since the retailer and manufacturer are often times not the same,
quality problems at the consumer level have a major impact on the manufacturer.
In Process evaluation tests
1. Colour matching:
• is done by comparison with a standard shade
• The color matching is also done on the skin
2. Texture
• This test is done to check the presence of solid unwanted particles in
the lipstick
• The test is important as regular usage of lipstick with gritty matter
can scratch the lips in the long run.
3. Softening point
• The softening point is the temperature at which a material softens
• This test is conducted to check the stability of lipstick at high temperature
• As per the standard requirement, the minimum softening point of
lipstick should be 55 °C
4. Melting point
• The determination of melting point is done in order to determine the
storage characteristics of the product
5. Breaking point test/ Cantilever
test
• This test measure the firmness and bending force of a lipstick
• An important property sought by users is that the product must not
bend, crumble, crack or break during application
• Selection of the correct base ingredient quantities, for example waxes
of specific melting points, is such to formulate a product with moulded stick
resilience, which possesses enough rigidity to withstand firm application to
the lips by the user
• This test gives the value of the maximum load a lipstick can withstand
before it breaks
• The lipstick is held horizontally in a socket and weight is applied at
a measured distance from the edge of the support
• The weight applied is increased gradually every 30 sec by a
predetermined increment until the lipstick breaks.
• The test should be carried out constant temperature conditions
• As per the requirement, the lipstick should withstand a breaking load
of minimum 200
6. Payoff Test
• This test gives the idea of mass release from the lipstick salve while
applying
• As per the requirement, the lipstick should pass this test if pay-off
is more than 0.0001gm/cm2
7. Rancidity test (Oxidative
stability)
• Can be done by using hydrogen peroxide and determining its Peroxide
Value
• As per the standard requirement, the rancidity should not be more than
10 (peroxide number)
8. Drop point test
• Indicates the temperature of transition from the solid or semi-solid
state to the liquid state
• The Ubbelohde method is used
9. Test for penetrability
• Carried out using a penetrometer
• A needle of specific dimension is allowed to penetrate the lipstick and
the depth of penetration is noted
10. Stability testing
• The stability is determined by accelerated stability testing
• Lipstick is kept at various temperatures and assessed for surface
defects, perfume, colour and application characteristics
• Ageing stability is determined by storing the lipsticks in an oven at
40oC and periodically checking the application characteristics,
crystallization and oil bleeding and comparing with a fresh sample
11. Microbiological tests
• Microbiological tests such as total viable count (TVC), testing for
gram-negative and gram positive pathogens
12. Presence of Heavy Metals
• The average user applies lipstick 2.3 times daily and ingests around 24
milligrams each day, so the lipstick should be free of heavy toxic metals, or
within the limits
• Lipstick generally contains lead, chromium, cadmium, arsenic and many
more toxic metals, which are carcinogenic in nature and may cause serious
illness
• As per the standard requirement, lead and arsenic should not be more
than 20 ppm and 2 ppm, respectively.
13. Sensory testing
• Are carried out by clinical research organization (CRO) with over 150
volunteers to determine the effects, perception and overall acceptability of
the various lipsticks after regular use at home
• The subjects will wear the given sample of lipstick once a day for
seven days.
• The following attributes will be judged by the volunteers:
Evaluation tests?
1. Improvement in appearance
of lips after application. (Radiance, lustre)
2. Does your lipstick spread
beyond lip edges after application?
3. Moisturizing effects of
lipstick after application
4. Improvement in texture
(cracking or chapping) of lips after application
5. Improvement in softness and
smoothness of lips after application
6. Application of lipstick and
wearable period, approx. >4 hours
7. Fragrance of lipstick after
application
8. Rate as per convenience and
easy use of packing of lipstick
9. Overall quality of lipstick
Summary
1. Lipstick may be defined as
dispersion of the colouring matter in a base consisting of a suitable blend of
oils, fats and waxes with suitable perfumes and flavors, moulded in form of
sticks to impart attractive gloss and colour, when applied on lips
2. There are three main types
of raw materials used in lip products: oils, waxes and colours
Posts
0 Comments