1 Styrene Butadiene Latex Siam Synthetic Latex Co., Ltd. Discussions:What is Latex?Latex CharacterizationSB Latex applicationsHealth hazard and safe handling informationQ&A
2 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 / ThawHeat
3 Advantages of LatexLow 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.
4 S/B Latex Compositions Function, ContributionStyreneHardness, strength, stiffness, good aging, high Tg polymerButadieneSoftness, flexibility, adhesion, poor aging, low Tg polymerWaterContinuous phase for emulsion polymerizationEnhances heat removal from reactionSurfactantImprove stability of LatexDefoamerControl foaming tendency of latex under processing or end use conditionsAntioxidantIncrease usage lifetime of product by reducing rate of oxidation (butadiene polymers)pH control agentControl pH during polymerizationAdjust pH after polymerization to provide stripper stabilityAdjust pH for customer specificationBiocideControl bacteria in latex which feed on organics present
6 Latex Characterization Solid contentThe 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 residueLatex 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 testThe 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.
7 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 propertiesAllows 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 temperatureTemperature 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).
8 Latex Characterization Tg Glass transition temperatureThe 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"), MFFTVOCs Volatile organic compoundsMeasuring 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 benzenesBacteriaWhat 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.
9 THE DRYING PROCESS ~ ~ ~ ~ ~ STAGE I Water evaporation: solids %, particles getcloser together andviscosity increases.Coalescence: solids%, particlesforced together andcoalesce.Film: interdiffusion,decrease in gaspermeability.STAGE IISTAGE III~ ~ ~ ~ ~
10 S/B Latex applications Paper coatingCarpet backingConstructionCan sealantWood adhesiveEtc.
11 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:Used as a binder for pigmented coating of paper and paperboard for offset printing.High wet and dry binding powerGood printabilityStiffnessBlister resistanceFold crack minimizationCarpet backing:Used for carpet secondary backing applications, providing excellent adhesion when either wet or dry.High tuft bindExcellent filler acceptanceExcellent mechanical stabilityLow odor/Low VOCsContain antioxidant
12 Cement & Construction: specifically designed for use in cement mortars.Improve bonding, tensile and flexural strengthDurabilityImproved water resistanceHigh chloride resistanceCan sealant:Used for can sealant and can seaming compound. For food and beverage can packaging.Excellent wet and dry adhesionComply with F&DA
14 Why is paper coated?To improve the optical properties (gloss, brightness, opacity)To increase the smoothness of the surfaceTo improve the printabilityTo bind the pigment particles to each other and to paperwe say that the binder “spot-welds” the pigment particles
15 Coated paper prints better Printed Uncoated PaperPrinted Coated Paper
16 Paper Coating Compositions Function, ContributionPigments:Calcium Carbonate & ClayFill voids and contour on the paper, make paper surface smoother, more even ink absorptionBinder (Latex / Starch)Bind pigment with the paperDispersantContinuous phase for emulsion polymerizationEnhances heat removal from reactionInsolubilizerImproves water resistance of the coating (wet pick) for offset printing.LubricantImproves runnability, reduces dusting on calender and slitters, sheeters in finishing.Dyeadjust colour of the coated paperOBAOptical Brightening AgentImproves brightness of coated paper by adsorbing UV light and re-emitting it as blue light.Makes the paper look brighter and “whiter”NaOHAdjust pH of coating color to range 8-9
17 Typical Paper Coating Formulation Formulation = Coating ColorIngredient PartsCalcium Carbonate 0 – 100Kaolin ClayPlastic PigmentsTotal Pigments 100Latex BinderStarch 4Thickeners – 1.0Lubricants (stearate) 0.5 – 1.0OBA – 1.5Defoamers – 0.3Cross-linkers (UF) 0.2 – 0.5pH 8 - 9Solids %Viscosity mPasCoating normally produced in the mill in a batch process (kitchen)Paper can have 1, 2 or 3 layers of coatingDow supplies:BinderHollow Plastic PigmentSolid Plastic Pigment
19 Carpet Segmentation BACKING TYPE Carpet Woven Tufted Needlefelt Tiles Auto MatsSyntheticGrassBathroomMatsUnderlayunitarySB/EVA/PVACFull BathSBOne SideTML/SBRubber Crumb /PU FoamPU/rubber/SBSB/PVC/PUNatural/SyntheticLatexPVC/BitumenunitarySBsecondarybackingSBFoamHSLBACKING TYPEEcoworxGelNo GelBathroommats
20 TUFTED CARPET CONSTRUCTION Yarn Primary backing Latex compound Secondarybacking
21 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 adhesionPrevent edge fraying when the carpet is cut for installationGood dimensional stabilityAdd weightRequired stiffness (‘hand’)By addition of other additives, contribute to ignition resistanceand conductivity
22 Carpet latex compound compositions Function, ContributionBinder (S/B Latex)Bind yarns with backing, Handed feelingFiller (CaCO3)Give bulk to the latex compound and reduce costDispersing agentOffsets the forces of attraction between pigment particles.Reduction of energy necessary to separate pigments into discrete particlesFoaming agentFroth the compoundFoam stabilizerprevents the foam collapsing while in the foam bankadjust colour of the coated paperThickenerIncrease 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.
23 Tufted carpet compound formulation DIRECT COAT (D/C)
33 Benefits of DL470 to concrete Make concrete stronger and more durableImprove adhesion, flexural strength and tensile strength with no loss of compressive strengthImpermeabilityReduce penetration of moisture and corrosive chemicalsAbrasion resistanceHigh traffic area e.g. car park
34 Benefits of DL470 to concrete (cont’) Thinner overlayAllow less material to be place to assure protectionFreeze/Thaw stabilityImprove resistance to moisture penetration and cracking.WorkabilityReduce w/c ratio, leads to higher density structure
37 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.
38 First aid measuresInhalation 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.
39 Fire fighting measures Extinguishing MediaWater fog or fine spray. Carbon dioxide. Foam. Dry chemical.Unusual Fire & Explosion HazardsWill not burn until water is evaporated.FlammabilityNon-combustible, non-flammable while an emulsion. Dried product will burn in a similar fashion to wood.Hazardous Combustion ProductsUpon burning, the dry product generates dense, black smoke.
40 Spill & Disposal Protect people: Protect environment: 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.