Styrene Butadiene Latex
Siam Synthetic Latex Co., Ltd.
Discussions:
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What is Latex?
Latex Characterization
SB Latex applications
Health hazard and safe handling information
Q&A
What is Latex?
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LATEX is a white, tacky, aqueous suspension of a hydrocarbon
polymer occurring naturally in some species of trees....or made
synthetically.
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made by emulsion polymerization techniques from a range of
monomers (styrene, butadiene, acrylates, etc).
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low in viscosity, ~ 50% water / 50% polymer, and are easy to
pour, mix and pump.
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stabilized by ionic forces of repulsion between the particles, and
also by the addition of suitable surfactants.
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Latexes may be destabilized by the following:
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Ions (especially multivalent cations Ca2+, Al3+)
Shear (mixing, pumping)
Freeze / Thaw
Heat
Advantages of Latex
• Low viscosity: It is an advantage to have the polymer in a liquid state for processing by
the customer.
• Aqueous: Latex may be used directly in aqueous formulations. There is no organic
solvent to remove (flammability, toxicity, environmental etc.)
• Unique manufacturing process: Fast reaction, good heat removal due to low viscosity.
• Polymer: A wide range of polymers are available using various combinations of
monomers. eg. The dried polymer may be:
– A clear, tough, tough rubbery film, which may act as a binder in filled systems.
– A hard plastic (white powder).
– A sticky (tacky) adhesive.
S/B Latex Compositions
Compositions
Function, Contribution
Styrene
Hardness, strength, stiffness, good aging, high Tg polymer
Butadiene
Softness, flexibility, adhesion, poor aging, low Tg polymer
Water
Continuous phase for emulsion polymerization
Enhances heat removal from reaction
Surfactant
Improve stability of Latex
Defoamer
Control foaming tendency of latex under processing or end use
conditions
Antioxidant
Increase usage lifetime of product by reducing rate of oxidation
(butadiene polymers)
pH control agent
Control pH during polymerization
Adjust pH after polymerization to provide stripper stability
Adjust pH for customer specification
Biocide
Control bacteria in latex which feed on organics present
Typical SCG-Dow S/B Latex properties
Solids content
47 - 54 %
Specific gravity
1.01 - 1.06
pH
5 - 10
Viscosity
50 - 600 mPa.s
Surface tension
40 - 65 dynes/cm
Styrene content of polymer
40 - 60 %
Vinyl Acid content of polymer
0-6%
Particle size
0.12 - 0.25 m
Latex Characterization
Solid content
The water and other volatile components are evaporated to determine the non-volatile (solid)
content of the latex. This 'solids content' reflects the amount of 'active' polymer, additives etc. in
the latex.
Filter residue
Latex residue is formed from the agglomeration of polymer particles. Latex is passed through a
standard sieve, and the dried weight of latex residue per litre of latex is recorded.
Fisheye test
The fisheye test is used to measure the film forming properties of the latex for coating
applications. Film continuity may be affected by waxes or silicon based defoaming materials.
Particle size (Light scattering)
The weighted average particle size is calculated from the measured dissymmetry of light
scattering. The dissymmetry is the ratio of the intensity of light scattered at 45 degrees and 135
degrees. The particle size is expressed in angstroms.
Latex Characterization
Particle size (HDC)
Hydrodynamic Chromatography (HDC) is a technique used for quantitative determination of
particle size and particle size distribution in latex samples. The latex particles are separated via
liquid chromatography according to their size.
Latex film properties
Allows certain predictions as to a latexes behavior and properties in end-use applications.
Latex film properties include:
Tensile strength, Elongation to break, Young's Modulus, Swell index, Gel content, MFFT, Tg,
Composition by FTIR.
MFFT Minimum film formation temperature
Temperature at which a latex will form a continuous film. Estimation of the MFFT is critical to
ensure that proper processing and drying conditions are chosen for developing a latex film during
end-use (eg. during drying on a paper machine).
Latex Characterization
Tg Glass transition temperature
The Tg is the temperature at which an amorphous (non-crystalline) material changes from a
brittle, glassy material to a flexible, rubbery state, or vice versa.
Some end-user important properties of polymers which correlate strongly with Tg: Tensile
strength, % Elongation, Flexibility ("Hand"), MFFT
VOCs Volatile organic compounds
Measuring VOCs is important to ensure specifications are being met.
Determine the level of odiforous components in the latex.
Examples of VOCs that are often measured include: Styrene, 4-VCH, 4-PCH, Alkyl benzenes
Bacteria
What does bacteria do to our latex? Gives a foul odor. Causes deterioration of physical
properties. Can cause residue (coagulation).
Bacteria control: Clean storage tank, clean shipping container, fast turnover.
STAGE I
THE DRYING PROCESS
Water evaporation: solids
50-60-70%, particles get
closer together and
viscosity increases.
STAGE II
Coalescence: solids
90-95-100%, particles
forced together and
coalesce.
STAGE III
~ ~ ~ ~ ~
~ ~ ~ ~ ~
Film: interdiffusion,
decrease in gas
permeability.
S/B Latex applications
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Paper coating
Carpet backing
Construction
Can sealant
Wood adhesive
Etc.
Dow Latex is modified styrene butadiene latex made by emulsion polymerization
for variety applications such as paper coating, carpet backing, wood adhesive, can
sealant and construction application etc.
Paper Coating:
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Used as a binder for pigmented coating of paper
and paperboard for offset printing.
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High wet and dry binding power
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Good printability
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Stiffness
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Blister resistance
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Fold crack minimization
Carpet backing:
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Used for carpet secondary backing applications,
providing excellent adhesion when either wet or
dry.
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High tuft bind
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Excellent filler acceptance
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Excellent mechanical stability
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Low odor/Low VOCs
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Contain antioxidant
Cement & Construction:
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specifically designed for use in cement mortars.
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Improve bonding, tensile and flexural strength
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Durability
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Improved water resistance
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High chloride resistance
Can sealant:
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Used for can sealant and can seaming
compound. For food and beverage can
packaging.
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Excellent wet and dry adhesion
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Comply with F&DA 175.300.
Paper Coating
Why is paper coated?
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To improve the optical properties (gloss, brightness, opacity)
To increase the smoothness of the surface
To improve the printability
To bind the pigment particles to each other and to paper
we say that the binder “spot-welds” the pigment particles
Coated paper prints better
Printed Uncoated Paper
Printed Coated Paper
Paper Coating Compositions
Composition
Function, Contribution
Pigments:
Calcium Carbonate & Clay
Fill voids and contour on the paper, make paper surface smoother,
more even ink absorption
Binder (Latex / Starch)
Bind pigment with the paper
Dispersant
Continuous phase for emulsion polymerization
Enhances heat removal from reaction
Insolubilizer
Improves water resistance of the coating (wet pick) for offset
printing.
Lubricant
Improves runnability, reduces dusting on calender and slitters,
sheeters in finishing.
Dye
adjust colour of the coated paper
OBA
Optical Brightening Agent
Improves brightness of coated paper by adsorbing UV light and reemitting it as blue light.
Makes the paper look brighter and “whiter”
NaOH
Adjust pH of coating color to range 8-9
Typical Paper Coating Formulation
Formulation = Coating Color
Ingredient
Calcium Carbonate
Kaolin Clay
Plastic Pigments
Total Pigments
Parts
0 – 100
0 - 100
0-8
100
Latex Binder
5 - 25
Starch
4
Thickeners
0.2 – 1.0
Lubricants (stearate)
0.5 – 1.0
OBA
0.2 – 1.5
Defoamers
0.1 – 0.3
Cross-linkers (UF)
0.2 – 0.5
-----------------------------------------------pH 8 - 9
Solids 50-75%
Viscosity 500-2000 mPas
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Coating normally produced in
the mill in a batch process
(kitchen)
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Paper can have 1, 2 or 3 layers
of coating
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Dow supplies:
– Binder
– Hollow Plastic Pigment
– Solid Plastic Pigment
Carpet Backing
Carpet Segmentation
Carpet
BACKING TYPE
Woven
Needlefelt
Tufted
unitary
SB/EVA/PVAC
Full Bath
SB
Tiles
One Side
TML/SB
Auto Mats
Rubber Crumb /
PU Foam
PVC/Bitumen
unitary
SB
secondary
backing
SB
Foam
HSL
Gel
Bathroom
mats
Ecoworx
No Gel
Synthetic
Grass
Bathroom
Mats
SB/PVC/PU
Natural/Synthetic
Latex
Underlay
PU/rubber/
SB
TUFTED CARPET
CONSTRUCTION
Yarn
Primary
backing
Secondary
backing
Latex
compound
Tufted carpet latex compound
Objectives:
• Good frothability and froth stability (coat weight control)
• Good tuft lock (prevent tufts pulling out)
• Penetrate the yarn tufts to bind the individual filaments (prevent
‘pilling’ and ‘fuzzing’)
• Good secondary backing adhesion
• Prevent edge fraying when the carpet is cut for installation
• Good dimensional stability
• Add weight
• Required stiffness (‘hand’)
• By addition of other additives, contribute to ignition resistance
and conductivity
Carpet latex compound compositions
Composition
Function, Contribution
Binder (S/B Latex)
Bind yarns with backing, Handed feeling
Filler (CaCO3)
Give bulk to the latex compound and reduce cost
Dispersing agent
Offsets the forces of attraction between pigment particles.
Reduction of energy necessary to separate pigments into discrete
particles
Foaming agent
Froth the compound
Foam stabilizer
prevents the foam collapsing while in the foam bank
Foam stabilizer
adjust colour of the coated paper
Thickener
Increase the viscosity of a latex compound to prevent the filler
settling.
Prevents the compound from penetrating through to the face or
back of the carpet.
Tufted carpet compound formulation
DIRECT COAT (D/C)
TUFTED CARPET
LICK APPLICATOR
Construction
Application of LMC
Deck coverings
-Bridge deck overlay
-Internal and external ship-decks
-Footbridge decks
-Rail wagons
Anticorrosive
Linings
-Chemical or machinery plant floors
-Septic tanks
-Parking structures
-Effluent drains
Flooring
Paving
-Commercial and Industrial floors
-Toilet floors, garage
-Railway platform, Road
Application of LMC
Integral
Waterproofing
Repairing
materials
Decorative
coatings
-Concrete roof-decks, render wall
-Water tanks, Swimming pools
-Septic tanks, Silos
-Cement stucco-like coatings
-Cement filling compound
-Self leveling cements
-Sprayed concrete for repair of
concrete structures
-Protective coatings for corroded
reinforcing bars
LMC Mix Design: 3-6 cm thick
(Parts by weight)
Component
Conventional concrete
LMC
Cement
1.0
1.0
Sand, 2NS (<0.5 cm)
2.6
2.6
Stone, 25N (<1.2 cm)
1.75
1.75
Latex/Cement
0
0.15
Water/Cement
0.45
0.37
Water reducer
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none
Air entr. agent
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none
Air content
5-8%
3-7%
* vary levels
Typical Formulation of LMC
M3
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Portland cement
Aggregate (0-12 mm)
DL470 (46% solid)
Potable water
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P/C (polymer/cement)
W/C (water/cement)
400 kg
1650 kg
130 kg
62 kg
= 0.15
= 0.33
LMC Model
1.
Initial Mixing
Unhydrated Cement
Latex
Aggregates
Air
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Latex deposit on cement & aggregate
LMC Model
3. Latex close packs around cement and aggregates,
cement partially hydrated
4. Latex film encapsulates fully hydrated cement
Benefits of DL470 to concrete
• Make concrete stronger and more
durable
– Improve adhesion, flexural strength and tensile
strength with no loss of compressive strength
• Impermeability
– Reduce penetration of moisture and corrosive
chemicals
• Abrasion resistance
– High traffic area e.g. car park
Benefits of DL470 to concrete (cont’)
• Thinner overlay
– Allow less material to be place to assure
protection
• Freeze/Thaw stability
– Improve resistance to moisture
penetration and cracking.
• Workability
– Reduce w/c ratio, leads to higher
density structure
Affect of Bridge deck corrosion
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Financial Costs
Traffic Delays
Lost Productivity
Increased Emission
Auto accident
Personal Injury
Health hazard and safe handling
information
Health hazard information
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Inhalation
No adverse effects are anticipated from inhalation.
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Ingestion
Single dose oral toxicity is considered to be low. No
hazards anticipated from swallowing small amounts
incidental to normal handling operations.
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Skin
Short single exposure is not likely to cause significant skin
irritation. Prolonged or repeated exposure may cause skin
irritation. Skin absorption is unlikely due to physical
properties.
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Eye
May cause slight transient (temporary) eye irritation.
Corneal injury is unlikely.
First aid measures
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Inhalation
No adverse effects anticipated by this route of exposure.
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Ingestion
No adverse effects anticipated by this route of exposure
incidental to proper industrial handling.
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Skin
Wash off in flowing water or shower.
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Eye
Irrigate immediately with water for at least 5 minutes.
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First Aid Facilities
An eye wash fountain and a general washing
facility should be available to the work area.
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Other Information
Never give fluids or induce vomiting if patient is
unconscious or is having convulsions.
Fire fighting measures
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Extinguishing Media
– Water fog or fine spray. Carbon dioxide. Foam. Dry chemical.
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Unusual Fire & Explosion Hazards
– Will not burn until water is evaporated.
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Flammability
– Non-combustible, non-flammable while an emulsion. Dried product will burn
in a similar fashion to wood.
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Hazardous Combustion Products
– Upon burning, the dry product generates dense, black smoke.
Spill & Disposal
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Protect people:
– Wear adequate personal protective equipment.
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Protect environment:
– Keep out of sewers, storm drains, surface waters and soil.
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Clean-up: For small spills:
– contain and cover with sand, sawdust or absorbent material.
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Clean-up: For large spills:
– contain and recover for disposal. If entry to drains or sewers has occurred,
system may plug. Flush system with large amounts of water.
Q&A
Thank you