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p u r e i n co s m e t i c s
Rheological Additives in Cosmetics
Contents
Introduction 2
Cosmetics and Rheology 4
ELEMENTIS Specialties Rheological Additives
for cosmetics 6
Aqueous-Phase Additives 7
•RhEoLuxE® Associate Thickeners 7
•hectorite - The Benefits 8
•BENToNE® hydrophilic Clays 8
Non-Aqueous-Phase Additives 10
• BENToNE® organophilic Clays 10
• BENToNE GEL® 11
• ThIxCIN® R Rheological Additive 13
Product Application and Selection 14
Incorporation & Equipment Guideline 15
INCI References 16
RHEOLUXE®
BENTONE®
BENTONE GEL®
NANOX™
THIXCIN®
are trade names of
ELEMENTIS Specialties
Today’s successful cosmetics products
need the right rheological properties.
And the correct choice of rheological additive
enhances the product in production,
storage stability and application.
ELEMENTIS Specialties rheological additives
for aqueous and non-aqueous formulations
are valuable and proven tools for you to use.
Personal care, skin care, sun care
and decorative cosmetics;
single-phase, suspension or emulsion;
all can benefit from
ELEMENTIS Specialties
rheological additives.
p u r e i n co s m e t i c s
Personal Care
Skin Care
Sun Care
Decorative Cosmetics
Rheology is the science of flow. Every time a lotion is poured, a cream squeezed from a tube or a lipstick
applied, rheology is involved. Even when products are at rest, it plays an important part in controlling
stability and suspension.
understanding a formulation’s rheological needs enables you to create the best possible products.
The rheology of a system is described in terms of its viscosity.
Viscosity is the resistance to flow and defined as:
Shear stress is the force per unit area applied and shear rate is the resulting velocity gradient.
Cosmetics experience shear rates varying from 0.001 s-1, from gravitational forces;
to over 20,000 s-1, when a cream is spread or an aerosol antiperspirant sprayed (Fig 1).
Cosmetics and RheologyStrong partners to create the best possible products
The way the viscosity changes at varying shear rates greatly influences the overall product stability and performance. A material which maintains a constant viscosity, regardless of shear rate, has Newtonian flow (Fig.2). Dilatant flow (Fig.2) is a form where viscosity increases with shear, sometimes encountered in highly pigmented/filled systems.
Pseudoplastic flow (Fig. 4), also known as shear thinning behaviour, and typical of many commercial systems, is when viscosity decreases with increasing shear rate.
Flow may require a specific stress to be initiated. This particular stress value is known as the yield point.A system having both shear thinning flow and a yieldpoint can be described as having plastic flow.
The rate of recovery of a system when stress is removed is also very important. When a shear thinning system shows delayed viscosity recovery, it is described as thixotropic (Fig.3). This is one of the most important types of flow in cosmetics. Controlling the degree of thixotropy enhances the application of a cream, eliminates dripping of a roll-on antiperspirant or allows brushmarks in a coat of nail lacquer to disappear, leaving a smooth film.
Viscosity can be temperature dependent. Correct choice of rheological additive allows you to create the ideal flow characteristics (Fig. 1) and also achieve thermostable rheology.
5
ELEMENTIS Specialties rheological additives can be broadly divided between aqueous-phase thickeners
and non-aqueous-phase thickeners. But it is important to remember the advantages
of oil-phase viscosity modification that can greatly improve emulsion based products.
ELEMENTIS Specialties additives for cosmetics are based on naturally occurring materials:
highly refined and beneficiated hectorite clay or castor oil derivatives.
ELEMENTIS Specialties Rheological Additives
for Cosmetics Improving aqueous, anhydrous and
emulsion-based products
Aqueous-Phase Additives
7
RhEoLuxE® Associative Thickeners
The RhEoLuxE® family of rheology modifiers are non-ionic polymeric thickeners designed specifically for the personal care market. RhEoLuxE® consists of urethane based and Polyether Polyol based associative thickeners with superior performance in difficult systems such as those containing high salt levels or with extremes in ph.Due to its structure, RhEoLuxE® is soluble in water, but associates with lipophilic materials to build viscosity.
Associative thickeners – mechanism of actionAssociative thickeners increase the viscosity of aqueous systems through a system of molecular associations and interactions. The thickeners consist of water soluble polymeric chains modified with hydrophobic caps.The hydrophobic caps of the polymer associate, that is build a structured network with other hydrophobes in the formula. This results in micelle type structures that form a network resulting in significant viscosity build.
The Rheoluxe range of products provides viscosity control in all types of emulsion systems, creating an exceptional sensory profile. Supplied as easy to handle solutions, Rheoluxe can be added at any point in the production process. Rheoluxe is heat stable, although cold process systems are possible.
Rheoluxe structure
hydrophobicCap
hydrophobicCap
hydrophilicChain
Associative thickeners | Mechanism of action
INCI Name Typical use level: Chemistry
Rheoluxe® 812 Bis-lauryl Cocaminopropylamine/hDI/PeG-100 Copolymer (and) Butylene Glycol 1.0 – 3.0% Polyurethane
Rheoluxe® 880 Bis-C16-20 Isoalkoxy TMhDI/PeG-90 Copolymer 1.0 – 3.0% Polyurethane
Rheoluxe® 8015 PeG/PPG-450/50 Trimethylolpropane Dodecyl ether 0.5 – 5.0% Polyether Polyol
98
BENToNE® rheological additives are non-abrasive. The skin feel imparted by BENToNE® hydrophilic clays is a pleasant silkiness, quite different to that associated with the majority of cellulose, polymer and polysaccharide-based thickeners.
Furthermore, as hectorite itself is insensitive to temperature variations, the BENToNE® products impart a thermostable viscosity control.
Surfactants can influence the rheological behaviour of hydrophilic clays.
Non-ionic surfactants, if they are highly ethoxylated, can adsorb onto the clay surface. This rarely causes problems either in flow control or activity of the formulation.
Anionic surfactants can act as dispersing agents and weaken the gel structure. Alternatives that eliminate or minimise any problems can normally be found.
however, cationic surfactants interact strongly and should be avoided.
organic and silicone-based liquids used in oil and wax-based cosmetics, and as the non-aqueous-phase in emulsions, benefit greatly from ELEMENTIS Specialties rheological additives. outstanding rheological properties are developed using BENToNE® organoclay rheological additives in their powder form or, even better, with BENToNE GEL® additives, their predispersed forms.
The benefits gained are:
• thermostable viscosity control
• thixotropic flow
• suspension control of pigments and actives
• emulsion stabilisation
• silky skin feel
BENToNE® organophilic Clays
hectorite is now reacted with special vegetable quaternary ammonium salts to produce organoclays able to thicken and gel organic liquids. The correct choice of BENToNE® additive is determined largely by the polarity of the system to be thickened.
Additive Application
BENToNE® 27 V •Intermediate to high-polarity organic systems such as esters and triglycerides - for nail lacquers, skin care, antiperspirants and lip products
BENToNE® 38 V •Low to intermediate-polarity organic systems such as volatile silicones and mineral oil - for antiperspirants, creams, lotions, eye products and suntan products
Non-Aqueous-Phase Additives
hectorite - The benefits
hectorite is a unique swelling clay offering several advantages. hectorite’s special properties, compared with bentonite, are:
• lower iron content • lighter colour •higher swelling capacity •greater gel strength •no crystalline silica
Due to its small size, platelet shape and large surface area, hectorite is able to form strong, stable viscous gels.
hectorite is a very effective thickener of water. Because of this and its other exceptional properties, it forms the basis of the BENToNE® hydrophilic clays.
BENToNE® hydrophilic Clays
BENToNE® MA, EW, and LT rheological additives provide thixotropy and suspension control to the aqueous phase.
BENToNE® MA and EW additives form gels by producing an open, 3-dimensional network of the individual clay platelets as shown in Figure 5.
The two products are stable across the range ph 6-11 and offer good tolerance to electrolytes.
BENToNE® LT forms a similar network, but it is strengthened by the presence of a special cellulose, greatly enhancing stability and thickening characteristics. BENToNE® LT is stable across a broader range, ph 3-11, and is also the least
electrolyte-sensitive product. BENToNE® MA and EW are in compliance with ECoCERT; The ecological and organic cosmetics standards.
INCORPORATION Hydrophilic Clays
Wetting • Medium to high-shear mixing • Add clay to water before addition of other ingredients • Disperse at moderate ph
Shear • Low shear (< 10 ms-1) = long mixing time (> 30 mins) • high shear (> 15 ms-1) = shorter mixing time (10-15 mins)
Time • 10 minutes hydration before adding other ingredients
Heat Water at up to 60°C (140°F) reduces hydration time
It is important to have only unadulterated water present at the dispersion stage. Surfactants or electrolytes should not be added until dispersion is completed For additional guidance see page 14
1110
BENToNE® additives need to be efficiently dispersed using high-shear equipment and then to be activated with the optimum level of a chemical activator, such as propylene carbonate.
BENToNE® organoclays form thixotropic gels by developing hydrogen bond bridges between the edges of adjacent platelets as shown in Figure 7.
BENToNE GEL®
BENToNE GEL® additives are optimally dispersed and activated predispersions of ELEMENTIS Specialties organoclays.
Benefits include:
• optimally dispersed
• high-shear dispersion not necessary
• no polar activation required
• easy to handle and use
• can be added at any appropriate and convenient stage in manufacture
A wide range of gels made from various cosmetics oils, esters and solvents are available. The use of a BENToNE GEL® enables you, the formula-tor, to achieve the maximum efficiency from the organoclay without the need for careful shearing and activation. on the production scale, time is saved and the highest degree of reproducibility attained, leading to potenial cost savings.
INCORPORATION
BENToNE GEL® additives can be added at any convenient suitable stage in the manufacturing cycle. BENToNE GEL® additives are very high-viscosity, shear thinning products. To ensure good homogeneous mixing is achieved, care must be taken to overcome large viscosity differentials existing between the BENToNE GEL® and the other lower-viscosity components. Choice of mixing equipment and the configuration within the mixing vessels are critical factors in developing the optimum performance of the BENToNE GEL® additive. The use of medium- to high-shear mixing equipment is recommended.
For additional guidance see page 14
Batch Processing
•Single-Phase Systems Always add the BENToNE GEL®, under shear, to a portion of the organic component or solvent with which it is most compatible. Mix until homogeneous before adding the other ingredients.
•Multi-Phase Systems (eg. emulsions) As for the single phase, but always ensure the BENToNE GEL® additive is thoroughly mixed in before the emulsification stage.
Continuous processing
The BENToNE GEL® should be added to the oil phase at any convenient point that meets the above guidelines for the batch processing. In multi-manifold systems, a flowable pre-mix of the BENToNE GEL® with a compatible oil or solvent should be made in a side pot.
Where only lower-shear mixing equipment is available, stir the BENToNE GEL® alone, in a small mixing vessel, if necessary, and then slowly add the most compatible component by portions, always ensuring the mixture is homogeneous at each stage.
ThIxCIN® R Rheological Additive
For the highest degree of thixotropy in aliphatic liquids, ThIxCIN® R additive is the product to use. In addition to its effective rheological properties, it gives water repellency, stabilises emulsions and acts as a stiffening agent in lipsticks and ointments. It can also be used as a dry binder in pressed powder systems.
(Where high-temperature resistance is needed, BENToNE® or BENToNE GEL® additives are recommended).
ThIxCIN® R is a castor oil derivative. It requires temperature-controlled activation within the range 55-60°C (130-140°F) and high-shear mixing to develop its full structure.
ThIxCIN® R is in compliance with ECoCERT; The ecologi-cal and organic cosmetics standards.
INCORPORATION THIXCIN® R additive
Wetting high-shear mixing Add ThIxCIN® R to oil Disperse to deagglomerate
Heat Temperature range 55-60°C (130-140°F)
Shear Shear for 20 minutes within this temperature range to activate
Cool Maintain shear to below 35°C (95°F) when cooling
For additional guidance see page 15
p u r e i n co s m e t i c s
13
Product Application and Selection Choosing the right rheological additive
Cosmetic products range from pressed dry powders to suspensions in liquids; from single-phase solid or liquid formulations to emulsions. The choice of rheological additive and level of use depends on the system and the desired performance criteria (Table pages 20/21).
The properties imparted by the rheological additive benefit different cosmetics in different ways. The advantages of using ELEMENTIS Specialties rheological additives are not always only the obvious ones, for instance:
Stick products (lipstick and antiperspirant) • maintain homogeneity in molten and setting stages • gain improved pay-out • increase high-temperature integrity • eliminate oil migration • reduce “creasing” around lips and eyes
Mascara • improve film-build • increase water-resistance • eliminate oil migration
Emulsions • elevate drop-point temperature of water-in-oil creams • eliminate syneresis • improve emulsion stability • enable cold-process emulsification • create novel viscosity effects
UV Sunscreen • eliminate ultrafine Ti02 skin-whitening problems • enhance sun protection factor (SPF) • optimise use of sunscreen actives • reduce separation and settlement
Antiperspirant Aerosols• uniform distribution of active ingredients• soft and dry skin feel• significant less whitening• reduced separation and settlement
14
Incorporation & Equipment Guideline
Shear Development Low Low Medium Med-high Med-high Very highGeneric Type Paddle Propeller Planetary Rotor/stator Impeller Homogeniser
BENTONE® MA, BENTONE® EW and BENTONE® LT additives – powders needing high-energy mixing
Conditions Suitable only for Suitable for BENTONE® MA, EW, LT additive Suitable forBENTONE® EW additive BENTONE®Use highest speeds Use highest speeds and carefully MA, EW, LT (> 3000 rpm). observe optimum mixer/vessel additives.
configuration.
Order of addition Clean water and rheological additive only.Avoid addition of surfactants or electrolytes until dispersion completed.
Special factors BENTONE® EW < 5 BENTONE® MA <10%pH of water neutral. BENTONE® EW < 5%Sift clay in gradually. Add BENTONE® LT < 4%defoamers, if needed, only pH of water neutral.after dispersion completed. Sift clay in gradually.
BENTONE® 27 V and BENTONE® 38 V additives – powders needing high-energy mixing
Conditions Unsuitable – Suitable for BENTONE® 27 V Recommendedinsufficient shear. and 38 V additives. for
Use highest speeds and carefully BENTONE® 27 Vobserve optimum mixer/vessel and 38 V configuration. additives.
Order of addition N/A Oil or solvent alone.Add organoclay and disperse.Add polar activator and continue dispersing.
Special factors N/A Ensure full wetting achieved before activation.Use optimum level of polar activator.Avoid the presence of surfactants until after activation.
BENTONE GEL® rheological additives – optimally dispersed and activated gels
Conditions Use maximum speed Use highest speeds and carefully Add gel toand dilute gel stepwise observe optimum mixer/vessel vessel, applyunder shear. configuration. shear prior toMin. 10 mins @ > 1500 rpm. adding other
ingredients by increments.
Order of addition Gel first, then oil or solvent Add gel to portion of oil/solvent Add oil toin ratio 60:40 gel to oil. under shear. Maintain shear gel stepwise.Mix and add other until homogeneous.components in steps.
Special factors Ensure mixture is Ensure mixture is homogeneous at each dilution stage.homogeneous at each Particulate materials, such as antiperspirant saltsdilution stage until flowable will assist in the dispersion in low-viscosity media.consistency achieved.
18
ELE-COS-BRO_EN 03-02-2003 16:52 Pagina 18
15
Trade Name INCI Name
RHEOLOGICAL MODIFIERS FOR AQUEOUS-PHASE
BENTONE® EW Hectorite
BENTONE® EW CE Hectorite
BENTONE® LT Hectorite, Hydroxyethylcellulose
BENTONE® MA Hectorite
RHEOLATE® FX 1100 Steareth-100/PEG-136/HDI Copolymer
NEW! RHEOLUXE® 880 Bis-C16-20 Isoalkoxy TMHDI/PEG-90 Copolymer
NEW! RHEOLUXE® 812 Bis-Lauryl Cocaminopropylamine/HDI/ PEG-100 Copolymer, Butylene Glycol
NEW! RHEOLUXE® 8015 PEG/PPG-450/50 Trimethylolpropane Dodecyl Ether
RHEOLOGICAL MODIFIERS FOR NONAQUEOUS-PHASE
BENTONE® 27 V Steraralkonium Hectorite
BENTONE® 27 V CG Steraralkonium Hectorite
BENTONE® 38 V Disteardimonium Hectorite
BENTONE® 38 V CG Disteardimonium Hectorite
THIXCIN® R Trihydroxystearin
RHEOLOGICAL MODIFIERS FOR NONAQUEOUS-PHASE
BENTONE GEL® 1002 V Cyclopentasiloxane, Disteardimonium Hectorite, Propylene Carbonate
BENTONE GEL® ABO V Crambe Abyssinica Seed Oil, Stearalkonium Hectorite, Propylene Carbonate
BENTONE GEL® CAO V Ricinus Communis, Stearalkonium Hectorite, Propylene Carbonate
BENTONE GEL® EUG V Octyldodecanol, Disteardimonium Hectorite, Propylene Carbonate
BENTONE GEL® GTCC V Caprylic/Capric Triglyceride, Stearalkonium Hectorite, Propylene Carbonate
BENTONE GEL® HSO V Helianthus Annuus (Sunflower) Seed Oil, Disteardimonium Hectorite, Propylene Carbonate
BENTONE GEL® IHD V Isohexadecane, Disteardimonium Hectorite, Propylene Carbonate
BENTONE GEL® IPM V Isopropyl Myristate, Stearalkonium Hectorite, Propylene Carbonate
BENTONE GEL® ISD V Isododecane, Disteardimonium Hectorite, Propylene Carbonate
BENTONE GEL® LOI V Lanolin Oil, Isopropyl Palmitate, Stearalkonium Hectorite, Propylene Carbonate
BENTONE GEL® MIO V Mineral Oil, Disteardimonium Hectorite, Propylene Carbonate
BENTONE GEL® MSO V Limnanthes Alba (Meadowfoam) Seed Oil, Disteardimonium Hectorite, Propylene Carbonate
BENTONE GEL® NGD V Neopentyl Glycol, Diheptanoate, Disteardimonium Hectorite, Propylene Carbonate
NEW! BENTONE GEL® OLV V Olea Europaea (Olive) Fruit Oil, Stearalkonium Hectorite, Propylene Carbonate
BENTONE GEL® OMS V C11-12 Isoparaffin, Disteardimonium Hectorite, SD Alcohol Denat
BENTONE GEL® PTIS V Pentaerythrityl Tetraisostearate, Disteardimonium Hectorite, Propylene Carbonate
BENTONE GEL® PTM V Phenyl Trimethicone, Disteardimonium Hectorite, Triethyl Citrate
BENTONE GEL® SS71 V Petroleum Distallates, Disteardimonium Hectorite, Propylene Carbonate
BENTONE GEL® TMF V Methyl Trimethicone, Disteardimonium Hectorite, Triethyl Citrate
BENTONE GEL® TN V C12-15 Alkyl Benzoate, Stearalkonium Hectorite, Propylene Carbonate
BENTONE GEL® VS-5PC V Cyclopentasiloxane, Disteardimonium Hectorite, Propylene Carbonate
BENTONE GEL® VS-5V Cyclopentasiloxane, Disteardimonium Hectorite, SD Alcohol Denat
Natural product
INCI References
p u r e i n co s m e t i c s
Before using any of our products please consult our Safety Data Sheets.
The information in this publication is, to the best of our knowledge, true and accurate, but since the conditions of use are beyond our control, no warranty is given or to be implied in respect of such information. In every case, caution must be exercised to avoid violation or infringement of statutory obligations and any rights belonging to a third party. We are, at all time, willing to study customers’ specific outlets involving our products in order to enable their most effective use.
ELEMENTIS Specialties Consumer Products EuRoPE ELEMENTIS Gmbh Stolbergerstrasse 370 50933 Cologne Germany Tel: +49 221 2923 2000 Fax: +49 221 2923 2010 e-mail: [email protected]
u.S. ELEMENTIS Specialties 469 old Trenton Rd. East Windsor, NJ 08512 Tel: +1 609 443 2000 Fax: +1 609 443 2422 e-mail: [email protected]
Visit our website: www.elementis.com
Local representative