1. Laundry Detergent Chemistry
David Binder
April 7, 2006

2. Outline General Requirements Surfactant Properties
Soil Removal Mechanisms
Types of Surfactants
Buffers
Chelating Agents
Enzymes
Anti-Redeposition
Bleaches and Optical Brighteners
Fragrances
Formulations
Evaluation
Challenges Facing the Detergent Industry
Structure of a Personal Care Corporation

3. General Requirements Clean a Multitude of Stains
Mud
Grass
Oily Food (e.g. spaghetti sauce)
Starch (pudding)
Wine
Sebum/Sweat
Lipstick
Clays
Grease/Oil
Ice cream (chocolate)
Fruit Juice
Blood
Excrement
Inks

4. General Requirements (continued)
Refreshing / Deodorizing
Not damage garment
Fabric
Dye/pigments
Safety
Manufacturing
Consumer
Minimize environmental impact
Commodity business
Highly competitive
High volume
Cost sensitive

5. Surfactants Surface Active Agents
Reduce Surface tension at air-water interface
Water: surface tension = 72 dynes/cm
Water + 1.0% Surfactant: Surface tension = 20 – 40 dynes/cm
Molecules generally have both hydrophilic and hydrophobic character
Types of Surfactants
Anionic (soap, sulfonates)
Nonionic (alcohol ethoxylates, alkylglucosides)
Zwitterionic or Amphoteric (betaine sulfonates, alkyl amine oxide)
Cationic (alkyltrimethyl ammonium chloride)

6. Micelle Formation

7. 3D Micelle of Soap

8. Surfactant Wetting

9. Contact Angle and Wetting

10. Soil Removal Mechanisms
Detergency (surface chemistry)
Mechanical
Chemical
Liquid Soil
Roll-up
Reduction in Soil Adhesion
Solid Soil
Liquefaction / Solubilization

11. Mechanism for Stain Removal

12. Anionic Surfactants Linear Alkyl benzene sulfonate (LAS)
Main Strengths
Inexpensive (unless oil is expensive)
Very effective at particulate soil removal
Weaknesses
Ca2+ sensitive (although not like soap)
Environmental Degradation concerns (banned in the Nordic swan countries)

13. Anionic Surfactants Soap Advantages Weakness Non-petroleum derived
Oil particulate soil removal
Weakness
Very Ca2+ sensitive
Need to separate low and high molecular weight acids and hydrogenate for odor control

14. Composition of Coconut Oil Fatty Acid%
Caproic acid
C 6:0
ND - 0.7
Caprylic acid
C 8:0
Capric acid
C 10:0
Lauric acid
C 12:0
Myristic acid
C 14:0
Palmitic acid
C 16:0
Palmitoleic acid
C 16.1 ND
Stearic acid
C 18:0
Oleic acid
C 18:1
Linoleic acid
C 18:2
Linolenic acid
C 18:3
ND - 0.2

15. Anionic Surfactants Alcohol ether sulfate Strengths
Milder to the skin than alkyl benzene sulfonate
Less effected by water hardness than other anionic surfactants
High foaming
Both the hydrophile and hydrophobe can be modified to give a range of chemical and physical properties
Improved proteinaceous soil removal
Weaknesses
More expensive of than alkyl benzene sulfonate.

16. Nonionic Surfactants Alcohol Ethoxylate Strengths Weakness
Ca2+ insensitive
Decrease critical micelle concentration (CMC)
Good for oil soil removal
Weakness
Very harsh towards hands (lipid extraction)
Forms a gel phase on dilution with H2O and needs to be processed at T > 125 oF (52 oC) or utilize significant amounts of mechanical energy
Higher levels of ethoxylation are solids and need to be melted and / or transported and stored hot
Alkyl phenol ethoxylates are less expensive than linear ethoxylates but are possible endocrine disruptors.

17. Commercial Routes for Production of Linear Alkylbenzenesulfonate

18. Synthesis of Fatty Acids and Alcohols from Plants & Animals

19. Synthesis of Alcohol Ethoxylate & Alcohol Ether Sulfate

20. Buffers Importance of buffers Maintaining an alkalinity reserve
Ease of obtaining the target pH during manufacturing
Common Detergent Buffers
pKa
Sodium Citrate
pKa3 = 6.3
Phosphates
pKa2 = 7.2
pKa3 =12.67
Borate (Borax, Na2B4O7·10H2O)
pKa = 9.24
Sodium Carbonate (Soda Ash)
pKa2 = 10.33
Sodium Silicate (Sand + NaOH)
pKa ~

21. Chelating Agents
Chelating agents complex Ca2+ and Mg2+ which allows for better surfactant efficiency.
Detergent Chelating Agents
Comments
EDTA
Impacts bioavailability of Ca2+. Not normally used in laundry applications.
Phosphates
Eutrophication
Zeolites
Solid particles, Increases septic tank burden
Sodium Carbonate
Precipitation of CaCO3 (used in powders)
Polymers of polycarboxylic acids
Very Expensive
Sodium Citrate
Most commonly used in liquid laundry detergents.

22. Enzymes
Biological macromolecules which have a high affinity for a select subset of stains
Advantages
Very efficient catalysts
Disadvantages
Difficult to stabilize (lifetime of a laundry detergent may last more than 6 months to 1 year
Sensitive to high pH (pH > 9)
Some surfactants denature proteins
Very expensive

23. Classes of Enzymes Protease Amylase Cellulase Lipase
Protein sensitive stains include: milk (casein), grass, meats, blood
Most widely used enzyme
Proteases will destroy other enzymes (enzymes are proteins)
Amylase
Degrade starch based foods
Cellulase
Reduces pilling by cleaving cellulose linkages
Lipase
Breaks down triglycerides (natural oils)
Works slowly and most effectively after the wash cycle is complete. Results in potential odor issues from the release of low molecular weight fatty acids.

24. Anti-Redeposition Keep suspended soils from redepositing on garments.
Modified cellulosics
Sacrificial layer provides a multi-wash benefit.
Cellulose deposits on cotton. Soil/stain deposits on cellulose. Cellulose (with soil) removed by detergent.
Benefit is only for cotton
Combination of anionic polymer (polyacrylate) with partially cationic polymer (polyvinylpyrolidone, PVP).
Mechanism is likely entrapment of particulates.
PVP also effective at reducing dye transfer
PVP
Lauryl methacrylate Acrylic acid copolymer, z/y > 10

25. Bleach Normally added to laundry process as a separate product.
Tide with Bleach powder is exception
Most common bleaches are chlorine bleach (¯OCl and peroxides)
Difficult or expensive to stabilize the bleach or other raw materials (from bleach) in the formulation.
Reacts with conjugated carbon double bonds to decolorize chromophores.
Denatures proteins by oxidizing the S-H bonds.

26. Optical Brighteners Fluorescent Whitening Agents
Generate a bluish hue that most people associate with a more satisfying white.
Worldwide consumers recognize about 2500 different shade of white.
Increases the brightness by converting UV light into visible light.
Emitted blue light hides yellow and brown tones making treated textiles (or paper appear whiter).
Generate a strong purple color when exposed to UV light.

27. How Do Optical Brighteners Work?
Highly strained system (steric hindrance)
Can control wavelength of light emission by changing steric and/or electron donating characteristics
Can alter solubility and deposition by changing the substituents (more hydrophobic or hydrophilic)

28. Fragrances
Important factor in consumer acceptance or rejection of product.
Top notes: Fragrance out of bottle.
Middle notes: Fragrance while doing laundry (smell on wet clothes).
Bottom notes: Fragrance on dry garments (need to with stand heat of dryer).
Target: Elusive “fresh and clean” smell.
Different cultures have different preferences, e.g., Gain targeted towards Hispanic market.

29. Laundry Detergent Formulations
Raw Materials
Percentage
Surfactants
10 – 30 %
Wt. ratio of anion : nonionic
~ 2:1
Buffer
1 – 3 %
Chelating Agent
0 – 5 %
Polymers
0 – 1%
Enzymes
0 – 1 %
Optical Brightener
0 – 0.20 %
Fragrance
0 – 0.50 %
Water (or Powder Filler)
90 – 50 %

30. Detergent Evaluations
Evaluations normally done in washing machines or on tergotometers.

31. Evaluation Need to acquire or make stains
Laborious and time consuming process
Reproducibility is major concern
For consumer stained garments, need to match stain intensity.
Laboratory made stains, need to weigh and apply stain reproducibly.
For example, to evaluate 4 products on 10 stain sets requires: (4 clothes/stain)*10 stains*4 products * 2 repeats = 320 stain clothes
Evaluation either by instrumental reading or panelists
Reflectance Colorimeter shades of color calibrated with black (0) and white (100).
Reflectance Colorimeter

32. Challenges Facing the Detergent Industry
Increasing cost of raw materials
Cost of transportation
Changing demographics
Manufacturing sector of the economy in decline means that few consumers get clothes really dirty
Nintendo effect leads to less youth participation in organized sports
Wal-Mart effect
Wall Street effect
Emphasis of reduction in capital expenditures
Leads to downsizing and outsourcing of manufacturing requirements

33. Structure of a Personal Care Corporation
CEO
CFO
Marketing
Finance
Supplier Chain
Advertising
Focus Groups
Purchasing
R&D
Raw Material
Suppliers
Manufacturing
Customers
Retailers
Wal-Mart
Drug / Food Stores
Consumers

34. Thank you!!