Transcript
SURFACTANTS
INTRODUCTION
Are surfactants of natural or synthetic
origin ?
• They can be either.
• Surfactants from natural origin (vegetable or animal) are known as oleo-chemicals and are derived from sources such as palm oil or tallow.
• Surfactants from synthetic origin are known as petro-chemicals and are derived from petroleum.
What does surfactant do ?
Water & Oil are mortal enemies
Surfactants acts as clamp
binding Water & Oil are together
Surface Tension –
Force between
two liquids
How does surfactant work?
Cleaning/DetergencyHow does cleaning take place ?
Real Soil Composition
Required Effects when Cleaning
How Surfactants Work
Surfactant : Definition
Substance which reduces surface/interfacial tension between two phases
Compounds having tendency to gather around the interface between two different materials by altering the properties of interface remarkably
Serves as good mediator to settle dispute between two phases which are not friends
Surfactants reduce the surface tension of water by adsorbing at the liquid-gas interface.
They also reduce the interfacial tension between oil and water by adsorbing at the liquid-liquid interface.
• Surfactants are molecules that preferentially adsorb at an interface, i.e.
• Solid/liquid (froth flotation)• Liquid/gas (foams)• Liquid/liquid (emulsions)
• Water: surface tension = 72 dynes/cm• Water + 1.0% Surfactant: Surface tension = 20 –
40 dynes/cm
• Significantly alter interfacial free energy (work needed to create or expand interface/unit area).
• Surface free energy of interface minimized by reducing interfacial area.
TYPES
INTRODUCTION
• Anionic (-ve)• Cationic (+ve)• Zwitterionic
(Charge depends on pH)• Nonionic (No charge)
N+
Br-
SO-Na+
O
OSodium dodecylsulfate (SDS)
Cetylpyridinium bromide
O
OP
O
OO
OCH2CH2N(CH3)3+
O-
Dipalmitoylphosphatidylcholine (lecithin)
O O O O OH
Polyoxyethylene(4) lauryl ether (Brij 30)
Anionic Surfactants
Carboxylates
Alkyl benzene Sulphonates
Soaps
LABS
FAS
Sulfosuccinate
Diester
Sulfosuccinate
Monoester
Uses : Anionic Surfactants
• Cleansing Formulation– Shampoo– Hand wash– Bath gels– Tooth Paste– Soaps & Detergents
Cationic Surfactants
Important Property Substantivity
Cationic Surfactants
Amphoteric Surfactants
N+
CH3
CH3
CH2COO-
CONH(CH2)3 N+
CH3
CH3
CH2COO-
Cocobetaine (CB)
Cocoamidopropylbetaine ( CAPB)
Uses : Amphoteric Surfactants
• Betaines are used in personal care products e.g. hair shampoos, liquid soaps, and cleansing lotions.
• All-purpose cleaning agents, hand dishwashing agents, and special textile detergents..
Nonionic Surfactants
Nonionic Surfactants
Water Solubility of NonionicsReason
Cloud Point
Effect of moles of EO on Cloud Points of Nonionic
Influence of Cloud Point on Soil Removal
HLB –Hydrophilic Lipophilic Balance
HLB is a means of expressing the hydrophilic property of surfactants in figures
HLB ValueSignificance
HLB Value 1 2 3 4 5 6 7 8 9 1011 12
13
14 15 16 17
18
Use
Water in oil emulsifier
Oil in water Emulsifiers
Wetting AgentsDetergent
s
Solubilizer
HLB According to Griffin (only for PEG types)
substantive to skin and hair
HLB = 20 ( 1 – SV / AV ) Where S V = Sap value of ester of polyhydric alcohol AV = Acid value of fatty acid used
Calculation of HLB value of PEG-7-glyceryl-cocoate
AV of cocofatty acid = 265 mg KOH/g SV of PEG-7-glyceryl-cocoate = 95
HLB = 20 ( 1 – 95 / 265 ) = 12.8
HLB According to Griffin (only for polyhydric alcohol types)
HLB = 7 + m * Hh + n * Hl where
• m - number of hydrophilic groups in the molecule• Hh - Value of the hydrophilic groups• n - Number of lipophilic groups in the molecule• Hl - Value of the lipophilic groups
• Ex : Calculation of HLB of SLES
• Formula of SLES : CH3(CH2)11O (CH2CH2O)2SO3Na
• HLB = 7 + (1 x 1.3 + 2 x 0.33 + 38.7)+(12 x - 0.475)• = 42
HLB According to Davis
Nonionic SurfactantsProperties
MOST COMMONLY USED ANIONICS
1. Alcohol Sulfates.
2. Ethoxylated Alcohol Sulfates.
3. Sulfosuccinates.
4. Linear Alkylbenzene Sulfonates.
5. Alpha Olefin Sulfonates.
ALCOHOL SULFATES
• History: Commercial usage began in the mid 1940’s.
• Made by the reaction of a fatty alcohol (C8-C18) with sulfur trioxide.
• The alcohol sulfuric acid is neutralized with sodium or ammonium hydroxide, or an amine.
CHARACTERISTICS OF ALCOHOL SULFATES
1. C12 (Lauryl) provides the highest foam.2. Hydrolyzes at pH < 4.5.3. Can be readily thickened when combined with
alkanolamides, betaines, amine oxides etc.4. Thickening can be greatly enhanced by the addition of
electrolytes 5. (NaCl, KCl etc.).6. Light color.7. Bland odor.
• Shampoos• Body Wash• Liquid Hand
Soap• Bath Products• Facial Cleansers• Syndet Bars
MAJOR APPLICATIONS
ETHOXYLATED ALCOHOL SULFATES
• History: Commercial usage began in the early 1950’s.
• Made by the sulfation of an ethoxylated fatty alcohol.
• Typically, the alcohol is lauryl (C12) and ethylene oxide is in the range of 2-3 moles.
• The salts are typically sodium or ammonium.
Lipophilic Hydrophilic
SODIUM LAURETH SUFATE
• More soluble than alcohol sulfates.
• Hydrolyze at pH < 4.5.• Enhance foam stability of LAS
(Linear Alkylbenzene Sulfonates).• More mild than alcohol sulfates.
Mildness is significantly improved when blended with a sulfosuccinate.
PROPERTIES OF ETHER SULFATES
EFFECT OF BLENDS ON IRRITATION15% ACTIVE
MEANSCORE
6.0
4.0
2.0
0
0 25 50 75 100
SLES
AOS
SLS
PERCENT DISODIUM OLEAMIDO MEA SULFOSUCCINATE
LINEAR ALKYLBENZENE SULFONATE (LAS)
• Prepared by the sulfonation of alkyl (typically C12) benzene with sulfur trioxide.
• Salts are typically sodium, ammonium or amines.
Lipophilic Hydrophilic
SODIUM DODECYLBENZENE SUFONATE
APPLICATIONS OF LAS
• Primary surfactant used in household and industrial products: liquid dish wash, car wash, laundry, etc.
• Rarely used in personal care.
• Stable in acidic products.
Sulfates Hydrolyze More Readily Than Sulfonates Due to the Weaker R-O-S Bond
Sulfonate:
Sulfate:
ALPHA OLEFIN SULFONATES
• Made by the sulfonation of C14-16 alpha olefin.
• Product is actually a mixture of Na 2,3 alkenylsulfonate and Na 3-hydroxy-alkanesulfonate.
ALPHA OLEFIN SULFONATES
Sodium 2,3 alkenylsulfonate
Sodium 3-hydroxy-alkanesulfonate
PROPERTIES
• Excellent foamer.• Difficult to thicken.• Stable in acid.• Used in both personal
care and house hold cleansers.
• More mild than LAS.
APPLICATIONS
• Liquid dish wash.• Acid cleaners.• Car wash.• Liquid hand soap.• Sulfate free cleansers.
SULFOSUCCINATES
• Monoesters are primarily used in personal care cleansers.
• Diester (sodium dioctylsulfosuccinate) is
the most cost effective wetting agent available.
TWO TYPES
MONOESTER(GOOD FOAMER, MILD)
DIESTER(POOR FOAMER, LOW SOLUBILITY)
MONOESTERS ARE FROM TWO SOURCES
• MONOALKANOL AMIDES
• FATTY ALCOHOLS, OR ETHOXYLATED ALCOHOLS
GENERAL DIFFERENCES BETWEEN SULFOSUCCINATE TYPES
AMIDE• Mild to skin and eyes.• Thicken and condition.
FATTY ALCOHOL• Mild to skin.• Foams better.• Water white color.
PROPERTIES
• Will hydrolyze in acid or alkaline conditions.
• Should be formulated in a pH range of 5.0-7.0.
• Are mild to skin and eyes.• The most cost/effective
mild surfactants available.
EFFECT OF BLENDS ON SKIN IRRITATION
SLES/DSLSS**SLES: Sodium Laureth Sulfate
DSLSS: Disodium Laureth Sulfosuccinate
5.0
4.0
3.0
2.0
1.0
0
4.74.0
1.50.9 0.9
100/0 75/25 50/50 25/75 0/100
EFFECT OF BLENDS ON FOAM
350420450
FOAM HT. (ml.)
500
400
300
200
100
0100/0 25/75 0/100
SLES/DSLSS**SLES: Sodium Laureth Sulfate
DSLSS: Disodium Laureth Sulfosuccinate
AMPHOTERICS/BETAINES
AMPHOTERICS ARE DERIVITIVES OF FATTY IMIDAZONES
AMPHOTERICS
Zwitter Ion (Isolectric Form)
Cationic (Acid Form) Anionic (Alkaline Form)
PROPERTIES OF AMPHOTERICSFOR HI&I APPLICATIONS
• Stable in alkaline and acid conditions.
• The propionate and dipropionate type are excellent for HI&I cleaners.
• Low and high foaming is dependant on the molecular weight of the fatty moiety.
• A C8 will be a low foamer, whereas, a C12 is a high foamer.
EXAMPLES OF CAUSTIC SOLUBILITY
CompoundCoco Dipropionate Caprylic (C8) Dipropionate Caprylic (C8) Propionate Caprylic (C8) Diacetate Coco Propionate Octyl Betaine Sodium Xylene Sulfonate
%NaOH41383028252322
COMPARATIVE FOAM HEIGHTS
Foam Ht. 210155145503010
Compound Cocamidopropyl BetaineCoco PropionateCoco DipropionateOctyl (C8) Betaine Capryl (C8) amidopropyl Betaine Caprylic (C8) Diacetate
PROPERTIES OF AMPHOTERICS FOR PERSONAL CLEANSING
• Stable over a wide pH range.
• Mild to skin and eye.
• Reduce irritation of ether sulfates.
EFFECT OF BETAINE AMPHOTERIC WITH SODIUM LAURETH SULFATE ON EYE IRRITATION
DRAIZESCORE
40
30
20
10
0
1000
7525
5050
2575
0100
SLES
AMPHO/BETAINE
COCAMIDOPROPYLBETAINE
DISODIUMCOCOAMPHODIACETATE
BETAINES
TWO TYPES
1. Alkyl2. Alkylamido
REASONS FOR BETAINE GROWTH
1. Formulators Became Familiar With the Advantages.
2. Recently Used In Household and Institutional Cleaners.
3. Favored Replacement for Diethanolamides
BETAINES
Cationic (Acid Form)
Zwitter Ion (Isoelectric Form)
BETAINES ARE BETTER VISCOSITY BUIDERS THAN
AMPHOTERICS
MODEL FORMULA
Sodium Lauryl SulfateAmphoteric or BetaineWater
pH=7.0
Wt.% 8.0 2.090.0
COCAMIDOPROPYL BETAINE
COMPARATIVE VISCOSITY BUILDING
DISODIUMCOCOAMPHODIACETATE
CPS(0000)
6.0
5.0
4.0
3.0
2.0
1.0
2.0 3.0 4.0 5.0 6.0
PERCENT NaCl
AMPHOTERICS ARE MORE MILD THAN BETAINES
EFFECT OF FREE AMINE ON EYE IRRITATION:BETAINE VS. AMPHOTERICDRAIZE
SCORE
40
30
20
10
0
1.0 2.0 3.0 4.0 5.0
PERCENT FREE AMINE
COCAMIDOPROPYLBETAINE
DISODIUMCOCOAMPHODIACETATE
50 ACTIVES: 15.0%
pH: 7.0
EFFECT OF BLENDING BETAINE WITH AMPHOTERIC ON EYE IRRITATION:
DRAIZESCORE
40
30
20
10
0
1000
2575
0100
PERCENT
COCAMIDOPROPYL BETAINE
DISODIUM COCOAMPHODIACETATE
ACTIVES: 15.0%
pH: 7.0
7525
5050
GENERAL DIFFERENCES
Mild to Skin
Mild to Eyes
Foam Boosting
Viscosity Building
Betaines Amphoterics
CATIONIC SURFACTANTS
Definition: The cation is the lipophilic portion of the molecule.
Types:• Quaternary Ammonium Compounds • Amine Salts
CATIONICS
Amine Salt:
LipophilicHydrophilic
Quaternary:
LipophilicHydrophilic
PROPERTIES OF QUATERNARY AMMONIUM COMPOUNDS
• Lower molecular weight are typically used as biocides.
• Higher molecular weight (C18) are excellent hair conditioners.
• Most are incompatible with anionic surfactants.
• Low foaming.• Extremely sensitive to hard water
and usually require a chelant.
MAJOR USES OF “QUATS”
• Biocides.• Fabric Softeners.• Hair Conditioners.• Antistatic Agents.• “Cheater” Wax.• Corrosion Inhibitors.• Leather Softening.• Pigment Dispersants.• Sewage Flocculants.
BIOCIDES
The most commonly used for household and industrial applications:
Lauryl Dimethyl Benzyl Ammonium Chloride
BIOCIDAL “QUATS”
MODE OF ACTION1. Reduce surface tension at
interface.2. Attracted to negatively charged
surfaces, including microorganisms.
3. Denature protein of bacterial or fungi cells.
4. Affect the metabolic reactions of the cell.
5. Vital substances leak out.6. Causes death.
FABRIC SOFTENERS
Most widely used
• Distearyl dimethyl ammonium chloride.
• Dialkyl imidazolinium methyl methoslfate.
MOST WIDELY USED “QUATS” USED IN HAIR CONDITIONERS
• Cetrimonium Chloride
• Stearalkonium Chloride
• Distearyldimonium Chloride
FATTY AMINE SALTS
• Compatible with anionic surfactants.
• Do not depress foam.• Excellent thickeners.• Insoluble in alkaline media.• Some are very mild to skin
and eyes.
MOST COMMONLY USED
• Alkyamidopropyl Dimethylamine
• Alkyamidopropyl Morpholine
COMPARATIVE EYE IRRITATION
Isostearamidopropyl Morpholine Lactate
Distearyldimethylammonium Chloride
Stearalkonium Chloride
Cetrimonium Chloride
4
4058
75
0
20
40
60
80
100
NONIONICS
• Alkanol Amides.
• Amine Oxides.
• Ethoxylated Nonyl Phenol or Alcohols.
PREPARATION OF ALKANOL AMIDES
Made by the reaction of a mono or diethanol amine with a fatty acid, methylester or fatty glyceride, (e.g., coconut oil).
REACTION(DEA Amide)
Diethanolamine + Fatty Acid Fatty Diethanolamide + Water
ALKANOL AMIDES
• Most cost/effective thickener and foam stablizer available.
• History: Commercially available in the mid 1940’s.
• Diethanolamides are being phased out of formulas due to reported “cancer link”.
• They are being replaced by: Betaines, Amine Oxides, Monoethanolamides and Monoisopropanolamides.
MONOETHANOL AND MONOISOPROPANOL AMIDES
• Both are solid at room temperature.• Both are used as replacements for
diethanol amides.• For clear products the level should be low,
or the product can haze due to the low solubility of the amides.
• The monoethanol amides have trace amounts of DEA which is not accepted by some customers. The MIPA is a better choice since DEA does not exist in MIPA.
AMINE OXIDES
• Prepared by the oxidation of a fatty tertiary amine with hydrogen peroxide.
• They are weakly cationic on the acid side.• The alkyl amine oxides are stable in the
presence of sodium hypochlorite and are excellent surfactants for bleach cleaners.
• Not widely used in personal care.
REACTION(Amine Oxide)
Fatty Tertiary +Amine
HydrogenPeroxide
Fatty Amine +Oxide
Water
ETHOXYLATED ALCOHOLS AND NONYL PHENOLS
CHARACTERISTICS
• Fatty end of molecule is lipophilic and ethoxylatated end is hydrophilic.
• Excellent detergent and wetting properties.
• Poor foamers.
• Can not be thickened with other surfactants.
MANUFACTURED BY:
• Ethoxylation of a natural derived straight chain fatty alcohol.
• Ethoxylation of synthetic branched chain alcohol.
• Ethoxylation of nonyl phenol.
REACTION(Ethoxylated Alcohol)
Ethoxylated AlcoholFatty Alcohol
Ethylene Oxide
+
REGULATORY STATUS OF ETHOXYLATED NONYL PHENOLS
• Banned in Europe.
• Banned in some states.
• Will eventually be banned in the U.S. and Canada.
H I & I APPLICATIONS OF NONIONICS
• Commercial Dishwash.
• Home Floor Carpet Care.
• Dairy and Food.
• Hard Surface Cleaning.
OTHER INDUSTRIES
• Paints and Coatings.• Agrochemicals.• Electroplating.• Textiles.• Pulp and Paper.• Oil Field.• Metal Working.
SOME NEW GUYS ON THE BLOCK “NATURAL SURFACTANTS”
• Decylglucoside: Derived from sugar and coconut oil.
• Cocoyl Glutamate: Derived from glutamic acid (amino acid) and coconut oil.
• Cocosulfate: Derived from coconut oil.
CURRENT TRENDS AND LIMITATIONS
• Natural.• Certified Organic.• Animal friendly.• DEA Free.• Formaldehyde Free.• Nitrosamine Free.• Sulfate Free.• Low Dioxane.
THAT’S IT “IN A NUTSHELL”
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