Styrene Butadiene LatexSiam Synthetic Latex Co., Ltd. Discussions: • What is Latex? • Latex Characterization • SB Latex applications • Health hazard and safe handling information • Q&A
What is Latex? • LATEX is a white, tacky, aqueous suspension of a hydrocarbon polymer occurring naturally in some species of trees....or made synthetically. • made by emulsion polymerization techniques from a range of monomers (styrene, butadiene, acrylates, etc). • low in viscosity, ~ 50% water / 50% polymer, and are easy to pour, mix and pump. • stabilized by ionic forces of repulsion between the particles, and also by the addition of suitable surfactants. • Latexes may be destabilized by the following: • 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.
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.
THE DRYING PROCESS STAGE I Water evaporation: solids 50-60-70%, particles get closer together and viscosity increases. Coalescence: solids 90-95-100%, particles forced together and coalesce. Film: interdiffusion, decrease in gas permeability. STAGE II STAGE III ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
S/B Latex applications • Paper coating • Carpet backing • Construction • Can sealant • Wood adhesive • Etc.
Dow Latexis 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: • Used as a binder for pigmented coating of paper and paperboard for offset printing. • High wet and dry binding power • Good printability • Stiffness • Blister resistance • Fold crack minimization Carpet backing: • Used for carpet secondary backing applications, providing excellent adhesion when either wet or dry. • High tuft bind • Excellent filler acceptance • Excellent mechanical stability • Low odor/Low VOCs • Contain antioxidant
Can sealant: • Used for can sealant and can seaming compound. For food and beverage can packaging. • Excellent wet and dry adhesion • Comply with F&DA 175.300. Cement & Construction: • specifically designed for use in cement mortars. • Improve bonding, tensile and flexural strength • Durability • Improved water resistance • High chloride resistance
Why is paper coated? • 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
Typical Paper Coating Formulation • Coating normally produced in the mill in a batch process (kitchen) • Paper can have 1, 2 or 3 layers of coating • Dow supplies: • Binder • Hollow Plastic Pigment • Solid Plastic Pigment Formulation = Coating Color IngredientParts Calcium Carbonate 0 – 100 Kaolin Clay 0 - 100 Plastic Pigments 0 - 8 Total Pigments 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
Carpet Segmentation Carpet Woven Needlefelt Tiles Auto Mats Synthetic Grass Tufted Bathroom Mats Underlay unitary SB/EVA/PVAC Full Bath SB One Side TML/SB Rubber Crumb / PU Foam PU/rubber/SB SB/PVC/PU Natural/Synthetic Latex PVC/Bitumen unitary SB secondary backing SB Foam HSL BACKING TYPE Ecoworx No Gel Gel Bathroom mats
TUFTED CARPET CONSTRUCTION Yarn Primary backing Latex compound Secondary backing
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
Tufted carpet compound formulation DIRECT COAT (D/C)
TUFTED CARPET LICK APPLICATOR
Application of LMC Deck coverings Anticorrosive Linings Flooring Paving -Bridge deck overlay -Internal and external ship-decks -Footbridge decks -Rail wagons -Chemical or machinery plant floors -Septic tanks -Parking structures -Effluent drains -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)1.751.75 Latex/Cement 0 0.15 Water/Cement 0.45 0.37 Water reducer * none Air entr. agent * none Air content 5-8% 3-7% * vary levels
Typical Formulation of LMC • Portland cement • Aggregate (0-12 mm) • DL470 (46% solid) • Potable water • P/C (polymer/cement) • W/C (water/cement) M3 400 kg 1650 kg 130 kg 62 kg = 0.15 = 0.33
LMC Model • Initial Mixing • Latex deposit on cement & aggregate Unhydrated Cement Latex Aggregates Air
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 • Financial Costs • Traffic Delays • Lost Productivity • Increased Emission • Auto accident • Personal Injury
Health hazard information • Inhalation No adverse effects are anticipated from inhalation. • Ingestion Single dose oral toxicity is considered to be low. No hazards anticipated from swallowing small amounts incidental to normal handling operations. • 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. • Eye May cause slight transient (temporary) eye irritation. Corneal injury is unlikely.
First aid measures • Inhalation No adverse effects anticipated by this route of exposure. • Ingestion No adverse effects anticipated by this route of exposure incidental to proper industrial handling. • Skin Wash off in flowing water or shower. • Eye Irrigate immediately with water for at least 5 minutes. • First Aid Facilities An eye wash fountain and a general washing facility should be available to the work area. • Other Information Never give fluids or induce vomiting if patient is unconscious or is having convulsions.
Fire fighting measures • Extinguishing Media • Water fog or fine spray. Carbon dioxide. Foam. Dry chemical. • Unusual Fire &Explosion Hazards • Will not burn until water is evaporated. • Flammability • Non-combustible, non-flammable while an emulsion. Dried product will burn in a similar fashion to wood. • Hazardous Combustion Products • Upon burning, the dry product generates dense, black smoke.
Spill & Disposal • Protect people: • Wear adequate personal protective equipment. • Protect environment: • Keep out of sewers, storm drains, surface waters and soil. • Clean-up: For small spills: • contain and cover with sand, sawdust or absorbent material. • 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