Laundry Science

Laundry Science
September 28, 2011
Louisville, KY

© 2011, Gurtler Industries, Inc.

Steven J. Tinker
• Gurtler Industries, Inc., Vice President,
Research & Development
– 35+ years in industry with Ecolab & Gurtler
– Technical Service
– Product development
– Marketing
• American Reusable Textile Association
Association,
President
– Mission: To create a greater appreciation for and
acceptance of reusable textiles.
• Healthcare Laundry Accreditation Council
Council,
Vice-Chair, Advisory Committee
– Founding member of Board, 2005


Part I - Laundry
Chemistry Basics
The Science of Cleaning


Laundry Chemistry Basics

Chemistry
affects all
aspects of the
laundering
process…


pH
• pH: Scale of values from 0 to 14 that measures
the relative acidity or alkalinity of a solution.
– pH 7.0 is neutral
– Alkaline solutions are > pH 7.0
– Acid solutions are < pH 7.0


Acid/Base
• Alkalies: Chemicals that release hydroxide ions
:
in solution: (- OH)
– Sodium hydroxide, metasilicate sod. carbonate
metasilicate,
• Acids: Chemicals that release hydrogen ions in
solution: (H+)
– Hydrochloric acid, sulfuric acid, phosphoric acid

In Water:
NaOH Na+ + -OH

HCl H+ + -Cl


Water

Water is 99+% of what we wash with,
therefore the quality of your water is
critical for the best results.


Water
• Water Hardness:
Calcium and magnesium carbonate, dissolved in water

– Grains per Gallon (gpg): measurement of the degree of
):
hardness, 1 gpg = 17.1 mg/l CaCO3
– Part Per Million (PPM): One milligram CaCO3 per liter of
water, 1 gpg = 17ppm


Water Hardness - CaCO3
Medium Very
Soft Hard
Hard Hard

0 to <75 75 to <150 150 to <300 300 mg/l and
mg/l mg/l mg/l greater

1 to 4 gpg 4 to 9 gpg 9 to 17.5 gpg > 17.5 gpg


Water Chemistry

• Total Dissolved Solids, TDS
– Measurement of all the solids (salts, hardness, etc.)
in the water
– Important in laundry, as this is also the solids that
would be left behind in fabric after it is dried


Water Chemistry

• Chlorine: Added to water supply for sanitation
– Usually added at 0.5 to 2.5 ppm
– Higher levels can cause corrosion or damage water
softener resins


Water Chemistry
• Iron
Major impurity that can cause problems in laundry
– Levels of 0.2ppm or more are a concern
– Causes yellowing of fabric
– Interferes with bleaching


Water Chemistry
• Alkalinity: Active and inactive
– Inactive (below pH 8.3) is also called
bicarbonate alkalinity
– High levels of inactive alkalinity can cause
rinsing difficulties


Water Chemistry
• Other issues:
– Acidity
– Color
– Suspended matter
– Organic growth
– Carbon dioxide and oxygen


Laundry Chemistry –
The Wash Process

• Soil Sorting
• Four Factors of Cleaning
• Wash Process
…and more


Sorting
• Match the process to the special requirements of
the classification
• Maximize soil removal while minimizing textile
degradation
• Cost effective use of chemistry, energy, time,
water and equipment


Sorting
• Soil Levels
– Very light, light, medium, heavy, extra heavy
– Special soil classifications: blood, grease, ink
• Colors
– Colorfastness, bleaching, dye transfer
• Fabric types
– Cotton vs. polyester


Loading Guidelines
• Weighing
– Clean, dry weight vs. soiled weight
• Machine types
– Open pocket vs. split pocket
– Tunnels vs. washer-extractors
extractors
• Fabrics


Basic Washing Process

Methods of cleaning:

– Diluting – Emulsifying
– Wetting – Deflocculating
– Neutralizing – Oxidizing
– Dissolving – Reducing
– Saponifying – Antiredeposition



Standard Laundry Process

Mechanical
Chemical Action
Action

Temperature Time



Low Temperature Process

Mechanical
Action
Chemical Action

Time
Temperature

Wash Process – Flush
• Flushing – removes
gross, soluble soils
– Blood soils - Keep under
110º F
– Also can increase the
temperature of the fabric
for more efficiency in the
next step
– Can use a small amount
of alkali or surfactant to
“wet” the fabric and
condition the soils


Flush Chemistry
• Alkali & Detergent (see Break Chemistry)
• Water & Soil Conditioners: Phosphates, organic
polymers
– Chelates water hardness & iron
– Suspends soils
– Aids in solubilizing soils
– State Phosphorus regulations
– Non-corrosive
SHMP EDTA-Metal complex


Wash Process: Break
• Break Cycle
– First step with alkali and
surfactant
– Can be separate steps
– With decrease in cotton, alkali
is less important
– Surfactants more effective on
polyester


Break Chemistry
• Alkalies: Usually based on Sodium Hydroxide or
:
“Caustic”
– “Break” up soils
– Saponify fats
– Neutralize acid soils
– Hazardous: Corrosive to skin and to some metals


Suds Chemistry
• Detergents or Surfactants:
Nonionic
– Low foaming
– Emulsifies oils
– Wets fabrics
– Neutral, non-corrosive


Wash Process
• Suds and Carryover
– Suds operation can be combined with the Break operation
for light soils
• Depending on the soil level, there can be multiple Suds steps
• Additional alkali and surfactant
– Carryover: Additional step that utilizes residual chemistry
from Break for continued soil removal action


Laundry Chemistry: Chelants
Water & Soil Conditioners: Phosphates, organic polymers
Sequester water hardness & iron
Suspends soils
Aids in solubilizing soils

SHMP EDTA-Metal complex


Wash Process: Bleaching
• Bleach Step
– Soils should be removed from the textiles and the
water should be clear
– Bleach is required to decolorize residual stains
– Temperature, pH, time and concentrations are key
factors


Laundry Chemistry: Bleaches
Bleaches decolorize stains
Oxidation
Chlorine Bleach
Hydrogen Peroxide (Oxygen Bleach)
Reduction
Oxalic Acid
Sodium Hydrosulfite


Bleach Chemistry
• Bleaches: Chlorine & Oxygen
– Oxidize stains (decolorize)
– Chlorine hazards:
• Incompatible with acids (sours)
• Very corrosive to metals, skin
– Peroxide hazards:
• Incompatible with alkalies
• Corrosive to metals, skin


Bleach Chemistry
Bleaching: Chlorine vs. Oxygen – Pros & Cons
• Chlorine – Pros:
– Excellent stain remover
– Highly efficient at 140°F
F
– Lower costs
• Chlorine – Cons:
– Can cause damage to cotton if misused
– Creates permanent Hibiclens stain


Bleach Chemistry
Bleaching: Chlorine vs. Oxygen – Pros & Cons
• Peroxide – Pros:
– Safer on colors and fabrics
– Does not affect Hibiclens (chlorhexidene gluconate)
negatively
• Peroxide – Cons:
– Not as effective stain remover
– Requires higher temperatures: 170
170-180°F
– Higher costs
– Requires DHS security assessment


Enzyme Technology
Alternative to bleaches
• Proteases: Protein soil removal
– Blood, BM
– Food-based stains
• High and low temperature varieties
– 100 - 130°F
– 130 - 160°F
• Effective at moderate alkalinity, pH 10.5


Enzyme Technology
Alternative to bleaches
• Amylases – Starches
– Food-based stains
• High and low temperature varieties
– 100-130°F
– 130-160°F
• Effective at higher pHs


Wash Process - Rinse
• Rinsing
– Remove residual chemicals and soils
– Reduce temperatures to 100ºF in 15º steps to
minimize wrinkles
– Three rinses are typical, some classifications require
more
– Intermediate extracts can be helpful
• Reduce water usage - increase wear


Wash Process –Antichlor

• Antichlors: Reducing agents
:
– Step prior to final rinse
– Neutralize residual chlorine
– Incompatible with acids
– Usually not corrosive or hazardous


Wash Process: Sour
• Sour:
o Final rinse, adjusts pH to 6.0
6.0-6.5
o Usually HFS, Phosphoric or Citric acids
o Corrosivity can be an issue
o Neutralize residual alkali from break step
o Neutralize inactive alkalinity from water


Finish Chemistry

• Finishes: Softeners or starches
– Softeners improve “hand” of fabric and reduce static
in dryer
– Starches increase body of fabric
• Natural versus synthetic
– Anti-Bacterial Treatments
Bacterial
– Water Repellent Treatments
– Soil-Release Finishes


Wash Process - Extract
• Extraction
– Removes excess moisture
– Extraction is more efficient than dryers or
ironers in moisture removal
– Recommend final rinse at 100ºF minimum for
better efficiency


Specialty Chemistries

• Specialty additives
– Solvent-detergents
– Enzyme detergents
– Brighteners
– Iron removal treatments
– Dust control additives


Basic Washroom Tests
• Water hardness titration
• Alkalinity titration
• Chlorine or Oxygen tests
– Active levels in wash process
– Concentrated bleach activity
• pH Indicator for final rinse
• Residual chlorine
• Iron
– In textiles
– In water


Sample Titration Report


Part II – Green Technology
Environmental Issues &
Water and Energy Conservation


Chemical Environmental Issues
• Surfactants – Biodegradability
• Phosphates – Eutrophication
• Solvents – Biodegradable/Renewable
• Bleaches – Chlorinated organics in wastewater
• Water and Energy Usage – How chemicals can
affect


Environmental Concerns
• Surfactants:
– The active cleaning agent in most detergent formulations,
– Surfactants change the chemical and physical
relationship between water and the surface to be cleaned.
– Surfactants loosen and suspend soil and enhance the
wetting property of water.
– Environmentally improved surfactants biodegrade to less
toxic and less persistent chemicals.


Environmental Concerns
• Biodegradation:
– Linear alcohol ethoxylates (LAEs) biodegrade to linear
alcohols and carboxylic acids, compounds typically with
lower environmental concerns.
– Alkylphenol ethoxylates (APEs), in contrast, might
biodegrade under anaerobic conditions to alkylphenols
which persist in the environment and are considered toxic
to aquatic organisms.
– Also, LAEs are soluble in cooler water and so might aid in
the development of low temperature, energy
energy-saving
detergents.


Green Product Technology
EPA Initiative:
APE (NPE) vs. LAE Surfactant Technology
– LAE surfactants that are considered more eco eco-friendly
due to their improved biodegradability.
– Many laundry chemical suppliers have a full line of
detergents available that utilize surfactant technology that
meets the requirements of the US EPA’s
Safer Detergent Stewardship Initiative (SDSI).


Biodegradable Surfactants
SDSI - Safer Detergent
Stewardship Initiative
• Elimination of detergents that are
not completely biodegradable.
• Detergent formulators have
alternative formulas available now.
• Industry conversion has begun, and
will progress over the next few
years.


NPE vs. LAE Surfactant Technology
• Europe has eliminated APEs.
• Canada fully converted to the new
surfactants at the end of 2010.
• TRSA has committed to EPA to work
to a full conversion to LAE technology
within their membership by 2014


Phosphates

Phosphates
cause premature
eutrophication
of lakes…


Phosphates
• Phosphates in laundry products:
– Sequester water hardness ions, preventing them form
interfering with detergent action
– Suspend soils
– Enhance detergent efficacy
• Since the early 1970s “P” has been regulated
– States developed limits and bans
– No national standard


Phosphates
• Laundry chemical manufacturers have limited
phosphate and non-phosphate formulations
phosphate
– Organic polymers have good performance
– EPA: Avoid NTA and EDTA
• New Research is continuing, as “green” issues
intensify
– Renewable and biodegradable alternatives are
available


Solvents

Hydrocarbon
solvents do not
biodegrade, plus
can pollute air…


Solvents
• Traditional solvents include:
– Odorless mineral spirits – aliphatic hydrocarbons
– Cyclical hydrocarbons – more aggressive, more
odiferous
– D-Limonene – extracted from oranges
– “Butyl Cellosolve” solvent
”
• All have negative environmental or health issues.


Solvents
• Safer solvents currently available
– DPM: More environmentally friendly, according
to EPA
• New research on “renewable” solvents
– Derived from plant sources, not petroleum
– Soy and corn-based
– Biodegradability is a plus


Chlorine Bleach

• Chlorine reacts with
organics in
wastewater –
Creates organo-
carbons/chloroform
Cancer-causing agents


Chlorine Substitutes
• Oxygen Bleaches –
Hydrogen peroxide
– Not as effective as a sanitizer or
stain remover
– Requires hot (>170°F) water for
F)
greatest effectiveness
– Does not react with
Chlorhexidene gluconate
(Hibiclens)


• “Activated” Oxygen Bleaches
–
Peracetic Acid
– Effective at lower temperatures
(120-140°F)
– More effective sanitizer than
peroxide
– Very high cost impact



• Enzyme Technology–
– Proteases & Amylases
– Effective at lower
temperatures (120-140°F)
– Excellent at odor removal


Green Fabric Softener Technology

• New Softener Technology
– Biodegradable softeners
– Renewable feedstock
sources:
• Plant-based chemistry vs.
based
petroleum or animal sources


What should you look for?
• Biodegradable surfactants
• Natural solvents
• Renewable raw material sources
• No or low phosphate formulas
• Super-concentration for reduced packaging
concentration
• Low temperature performance


Water and Energy Conservation
• New technologies designed for water reuse and
heat transfer have been introduced to the laundry
industry.
• Aggressive development efforts in new water and
energy conservation efforts continue.
• Retrofitting older equipment may be an option.


Water and Energy Considerations
• Water Reuse – Chemical
Considerations
– Neutral and low alkaline detergents
– Improved soil suspension agents and
additives
– Higher levels of water conditioners
• Reuse of water allows for reuse of
chemicals.
– Rebalance chemical usage


Part III – Textiles


Textiles


Textiles
Cotton Polyester


Textiles
Cotton Fiber

Microfiber
Polyester Fiber


Laundering Polyester/Microfiber
• Polyester Properties
– Softer, “cotton” feel
– Absorbent
– Soil release
properties/finish


Traditional high alkaline and
high temperature washing
methods are not the most
efficient or effective.
• Low alkaline, high surfactant
technology is most effective.
• Medium temperatures (140-160ºF)
160ºF)
are best


Oily Soils are the most
difficult to remove
• Detergents should be
balanced to low HLB value;
more oleophilic in nature.
• Phosphate builders aid in oil
emulsification and removal


Damage to Polyester - Alkaline Hydrolysis


Laundering Polyester
Damage to Polyester
• Alkaline Hydrolysis
– Caused by extra high
alkalinity combined with
high temperatures
– Fibers will scale and
fracture
– Lint may be a problem


Alkaline Hydrolysis Undamaged Fiber


Undamaged Fiber Damaged Fibers


Heat Damage
• Polyester will melt at
250ºC or 482ºF


Heat Damaged Fibers


Part IV – Hygienically
Clean Textiles


Pathogens: “Superbug” Awareness

• Increased awareness of resilient pathogens
– MRSA: Methicillin Resistant Staphylococcus Aureus
• Very difficult to control when a patient is infected.

– C-Diff: Clostridium Difficile
• Spore form survives on surfaces and is very difficult to
deactivate.

MRSA Hepatitis B C. Diff


Hygienically Clean Textiles
Definition –
• The textile has been treated such that "bioburden" has been
adequately removed so that the item can be used without fear
of being a source of contamination in a healthcare use.
– And that the item can be treated with normal methods (steam
sterilization) as needed to sterilize the textile.
• AAMI (Association for the Advancement of Medical
Instrumentation) defines the term "hygienically clean" as "free
of pathogens in sufficient numbers to cause human illness.”


The Laundering Process
The wash process utilizes several techniques to assure that the
bioburden is reduced or eliminated. These techniques include:

• Dilution: Several water changes during the cleaning process
physically remove and flush away bio bio-organisms. Mechanical
action is also a factor to consider as bioburden is loosened from
the fabric by proper mechanical action
action.

• Heat: Washing at elevated temperatures (>140ºF) deactivates
much of the common bio-organisms.
organisms.


• pH: High pH (>10.5) will "attack" or deactivate bio bio-
organisms. In addition, large swings in pH, from neutral (7.0 -
8.0) in first flushes to alkaline (10.5 - 11.5) during the main
wash cycles to acid (5.5 - 6.5) will adversely affect bio
bio-
organisms.


• Oxidation: Chlorine bleach or oxygen bleaches contribute to
the bio-organism deactivation –
organism
– Chlorine bleaches are well known to have excellent anti
anti-bacterial and
anti-viral efficacy.
– Oxygen bleach is considered to be somewhat less aggressive on
bacteria and viruses, however, when combined with the other cleaning
factors in a laundry formula, oxygen bleach is considered effective in
deactivating residual microbes.
– Peracetic acid is an “activated” oxygen bleach that also has excellent
anti-microbial and anti-viral activity.
viral


• Drying: Drying or ironing at temperatures that exceed 180ºF
on the fabric surface deactivate any potential remaining
organisms.

• Chemical Sanitizers or Bacteriostats: Some laundries as an
extra precaution will use EPA registered products that will
act as sanitizers in the final step of the laundry process.


• Published reports by ALM (Association for Linen
Management), TRSA (Textile Rental Service Association),
CDC (Centers for Disease Control and Prevention) and
AAMI indicate:

A well designed wash formula that appropriately uses
the above techniques will provide "hygienically
clean" textiles.


Low Temperature Washing
• Published reports by TRSA and AAMI indicate that a well
designed wash formula will provide "hygienically clean"
textiles, even at lower wash temperatures.

• CDC: “Studies have shown that a satisfactory reduction of
microbial contamination can be achieved at water
temperatures lower than 160 if laundry chemicals suitable
160°F
for low-temperature washing are used at proper
temperature
concentrations.”
http://www.cdc.gov/ncidod/dhqp/bp_laundry.html


Low Temperature Washing
• Veteran’s Administration sponsored a research study that investigated the
effect of low temperature and chemical oxidation on the “hygienically clean”
aspects of the laundering process used in their laundry facilities.

• This study is entitled “Killing of Fabric Associated Bacteria in Hospital
Fabric-
Laundry by Low Temperature Washing” ( (Blaser, et al., Journal of Infectious
Diseases, Vol. 149, No. 1, Jan. 1984, 48
, 48-57).

• The article concluded that there was sufficient reduction of pathogenic
bacteria, even in low temperature washing (22ºC, 72ºF).

• It also noted that even with the elimination of chlorine bleach adequate
bleach,
reduction in pathogens was observed when compared to traditional high
temperature (71ºC, 160ºF) washing processes.


Questions?


Contact information

Steve Tinker
Office: 708
708-331-2550
Cell: 708
708-870-7743
sjtinker@gurtler.com


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