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WEL COME

WEL COME. PVC PIPE EXTRUSION. TOPICS COVERED. 1. Introduction, Historical review. 2. Manufacturing of PVC. 3. Types of PVC. 4. Resin properties & its effect on end use of performance. 5. PVC compounding.

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WEL COME

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  1. WEL COME PVC PIPE EXTRUSION

  2. TOPICS COVERED 1. Introduction, Historical review. 2. Manufacturing of PVC. 3. Types of PVC. 4. Resin properties & its effect on end use of performance. 5. PVC compounding. 6. Types of Extruder & processing technique. 7. PVC pipe manufacturing process. 8. Miscellaneous.

  3. PVC -- a common choice

  4. HISTORICAL REVIEW OF PVC PIPES

  5. ADVANTAGES OF PVC PIPES 1. Corrosion Resistance. 2. Maintenance free. 3. Easier to install. 4. Light weight. 5. Easy joints technique. 6. Variety of joining technique. 7. Low overall cost an installation. 8. Resistance to chemical. 9. Non toxic. 10. Biological resistance. 11. Abrasion resistance. 12. Different color choice available. 13. Energy saving. 14. Environmental friendly. 15. Recyclable. 16. Fire resistance.

  6. TYPES OF PVC PIPES 1. Agriculture pipes. 9. Threaded pipes. 2. Plumbing pipes. 10. Slotted pipes. 3. Plain pipes. 11. Screen pipes 4. General purpose pipes. 12. Casing pipes. 5. Socketed pipes. 13. Foam core pipes. 6. Corrugated pipes. 14. PVC flexible hoses. 7. Conduit pipes. 15. PVC breaded hoses. 8. Ducting pipes. 16. Flat hoses.

  7. CHARACTERISTICS OF PVC PVC is the positive choice for many specifiers and consumers because it has many great characteristics : 1. It is durable. 2. It is versatile. 3. It is safe and hygienic. 4. It offers great technical advantages. 5. It is innovative. 6. It saves resources and energy. 7. It is recyclable. 8. It is cost effective.

  8. STRUCTURE OF PVC 1. PVC monomer. 2. PVC polymer. The macromolecule polyvinyl chloride (poly = many) is built from very many molecules of the monomer vinyl chloride. All these monomers are combined to PVC. These macromolecules are three-dimensional. They look like a knot of wool.

  9. POLYMERISATION OF VINYL CHLORIDE Vinyl Chloride Monomer ( VCM ) Vinyl chloride ( A gas boiling at -13.4 Deg.C ) is the monomer. This VCM used to manufactured PVC. CH2=CH2+Cl230 - 50 o C CH2-CH2 Cl Cl Ethylene Fe-Chloride Ethylene dichloride ( EDC ) CH2 - CH2 Cracking CH2=CH + HCL Cl Cl 300-600oC (20 sec) Cl 40-60% conversion Vinyl chloride. [ OXYCHLORINATION ] Finally divided CuII Chloride 2CH2=CH2+4HCL+O2 2CH2-CH2+H2O Cl Cl

  10. Types Of Polymerisation PVC resin today is manufactured primarily by three processes. The following are the processes. Suspension polymerisation. Bulk or mass polymerisation. Emulsion polymerisation. Suspension polymerization produces about 85% world's PVC.

  11. Types Of Pvc A] Rigid PVC. ( RPVC / upvc ) Rigid PVC pipes, window profile, B] Flexible PVC. Flexible garden hoses,films C] CPVC Plumbing, Fire sprinkler & Building products.

  12. Resin Properties & Its Effect On End Use Performance The performance of a PVC compound depends on following properties of the polymer. 1. K-value. 2. Apparent bulk density [abd] 3. Powder flow time. 4. Average particle size & particle size distribution. 5. Porosity. 6. Fish eyes. 7. Dark particles. 8. Heat loss. 9. Residual vcm. 10. Electrical conductivity. 11. PVC resin specifications for PVC pipe.

  13. PVC COMPOUNDING PIGMENT LUBRICANTS PVC RESIN FILLER STABILISER . FOAMING AGENT IMPACT MODIFIER

  14. TYPES OF EXTRUDERS • Single screw extruder. • Twin screw extruder a] Single line. b] Twin line. • Co extrusion.

  15. PVC CAN BE PROCESS BY FOLLOWING TECHNIQUE 1. EXTRUSION. 2. CALENDRING. 3. CO-EXTRUSION FILM. 4. THERMOFORMING. 5. INJECTION MOULDING. 6. BLOW MOULDING. 7. ROTO MOULDING 8. REACTION INJECTION MOULDING.

  16. PROCESS FLOW CHART

  17. THROUGH PUT TIME FOR ORDEREXECUTION DEPENDS ON …. • Economical run. • Time factor. a] Casing pipe. b] Slotting pipe. c] Large dia. Pipe. d] Special pipe. • Color of product. • Product limitations.

  18. THANK YOU .

  19. PVC Monomer

  20. PVC Polymer

  21. Suspension Polymerisation In suspension process vinyl chloride monomer is dispersed in water with stirring. Organic peroxides are used as initiators. After the polymerization , non reacted vinyl chloride is recovered to monomer recovery plant. The polymer suspension is then centrifuged to remove free water and wet polymer is dried by hot air. The particle size of PVC resin is about 100-150 microns.

  22. Bulk Polymerisasion In bulk polymerization vinyl chloride monomer is made to react with the initiator after having been brought to the required temperature. The first particles are precipitated after 0.1% of the vinyl chloride has reacted. The particle size of PVC resin produced is about 20-200 microns. The produced by this process is the purest form. Hence resin finds application in clear transparent application.

  23. Emulsion Polymerisation Emulsion polymerization vinyl chloride is dispersed in water by stirring and using surface active agents. Water soluble initiators such as hydrogen peroxide or per sulfates are used . The end product of polymerization reaction is fine particles of milky PVC latex. The final product is a mixture of primary particles <1.5 microns and secondary particles of 5-20 microns.

  24. WHAT IS CPVC .

  25. K-value The average molecule weight of PVC resin is designated as k-value. An increase in k-value leads to an increase in molecular weight, mechanical propertiesbut the melt viscosity becomes higher making processibility more difficult. K-value 67 provides best optimised performance in rigid applications like PVC pipes.

  26. K-value and Properties. Property PVC K 58 PVC K 67 ProcessabilityFitting Pipe Fusion Easy Slow M.F.I. LowHigh Impact resistanceGood Better Long term pressure Resistance Low Good

  27. Apparent Bulk Density The apparent bulk density covers the measurement of flowability of PVC powder, which is useful in predicting its storage, handling and processing characteristics. It is also a measure of fluffiness of the powder and is expressed as weight for unit volume of PVC powder including voids.

  28. Powder Flow Time Flow time is measure of time required for a standard quantity of resin to flow through a funnel of specified dimensions, and it characterizes the readiness with which it will flow through the hopper of processing machinery and feed tubes to deliver uniform weight of materials. The inherent flowability of PVC powder is determined by adding the given quantity of powder, which has first been treated with methanol to remove any static, to a standard funnel and measuring the time required for the powder to drain from the funnel. This time is called the static free funnel flow time.

  29. Particle Size Particle size is one of the most obvious ways of distinguishing between different types of PVC resins: dispersion resin, dispersion-blending resin & general-purpose resin. Particle size of general-purpose resin can affect bulk handling properties and processing characteristics. An excessive amount of fine particles (smaller than 75 microns) can cause dusting and packing problems when adding plasticizer. Coarse particles (425 microns and larger) cause gel problems in processing due to their poorer absorption and fusion characteristics. In general, fineness may indicate following: 1.. The resin will be more difficult to convey. 2.. It will be more susceptible to static charges. 3.. It will increase surface area and thus would require more lubricant.

  30. Porosity Porosity of PVC determines how much and how fast the plasticizers will be absorbed by the resin. A known amount of sample is vacuum impregnated with dioctylphtalate (DOP). Filtration and centrifugation remove the excess dop. Weight of DOP absorbed Porosity (ml/gm) = -------------------------------------------- Density of DOP x sample weight The following properties are affected with the increase in porosity: Rate of plasticizer absorption : Increase. Bulk density : Decreases. Dry blending time : Decreases. R-VCM content : Decreases.

  31. Fish Eye Fish eye test is carried out on a resin to check the presence of glassy particles with very low porosity. The fish eye is recognised as a hard particle of resin which is not homogeneously mixed and fused into the surrounding mass of the material during the working conditions associated with fusion of a PVC compound. The resin sample to be tested is compounded into standard formulation containing plasticizers, stabilizers and a pigment. The resulting mixture is then fused under controlled condition in plasticorder and is then compression moulded into thin sheet. The fish eyes, visible as clear spec in a die 36-sq.Cm film are then accurately counted by placing against light source. The following properties are affected with the increase in fish eyes: Clarity (films, bottles) : Decreases Impact property (rigid) : Decreases Surface appearance : Decreases Mechanical property : Decreases

  32. Dark Particles Level of dark specks can be measured by two methods: .Conveyor method : This procedure facilitates quantitative determination of the level of the dark specks contamination present in a given surface area of the resin. The resin conveyor is used to increase the visible surface area of the resin sample so that it can be examining and inspected, yielding a quantitative measure of contamination. In addition movement of the conveyor belt will diminal inspection of minute particles, which are not objectionable in most resin applications. .Syntron method : This test provides a quantitative measure of degree of contamination of suspension resin examining a measure quantity of resin for contaminants as it moves down the feeder through in single layer performs the test. Each discolored particle is counted and classified as dark resin, light resin or magnetic iron.

  33. Heat Loss PVC resin contain some volatile mainly in the form of absorbed moisture .A sample of the material to be tested is weighed into a preweighed container and heated in an oven .The loss of weight is calculated as percent heat loss, the non-volatile (solid) residue is calculated as percent total solids. The following properties are affected with the increase in heat loss: Porosity : Increases Processability : Decreases Product quality : Decreases

  34. Residual Vinyl Chloride Monomer[ VCM ] A minor quantity of vinyl chloride monomer will always remain absorbed in the resin. As vinyl chloride monomer is highly toxic, the measurement of residual VCM content in resin is very important. This residual VCM is measured by head space gas chromatography and is expressed in parts per million parts of resin.

  35. Electrical Conductivity This test is intended to distinguish between the electrical and non-electrical grades of unprocessed resin. A water dispersion of the resin is boiled for a short time and the electrical conductivity of the solution is measured. Electrical grade resins are recommended to provide conductivity values less than 6 micromhos/cm.G.

  36. PVC RESIN SPECIFICATION FOR PVC PIPE .

  37. PIGMENT

  38. LUBRICANTS. 1. Internal Lubricants : * It is use as lubricants for transparant products. * It reduce internal friction. * It give better wall thickness to product. * It reduces viscosity. * Slight effect on fusion time. * It has negative effect on softening point. * It is no real effect on sticking of the polymer to metal.

  39. LUBRICANTS.. 2. External Lubricants : * It reduces sticking to metal surface. * It is not compatible with polymer. * The fusion time will be made longer. * It reduces plate out. * It reduces melt friction. * It reduces burning of PVC during processing.

  40. FILLER Filler are added to PVC for giving specific property : * Improvement of flow behavior of melt in die head. * Reduces shrinkage. * Reduces cost of compound. * Improvement in heat conductivity of PVC. * To make opaque product. * Improvement in stiffness. * Upto 2 -3 phr they add as a processing add and more than this they are filler.

  41. TYPES OF FILLER 1. Calcium carbonate. a] Activated & Coated. b] Natural. ( Calcite ) 2. Gypsum 3. Talc. 4. Barrite. 5. Calcium Magnesium carbonate. 6. Silicates. 7. Calcium sulfate. Disadvantages of excess use of filler : * Long term pressure resistance.- Reduces * Impact resistance.- Reduces

  42. IMPACT MODIFIER Specific application of PVC leads modification of formulation by adding the impact modifier. Types of Impact modifier * Chlorinated polyethylene. [ C.P.E. ] * Ethylene vinyl acetate copolymer. [ E.V.A. ] * Acrylonitirile butadiene styrene terpolymer.[ A.B.S.] * Methacrylate butadiene styrene terpolymer.[ M.B.S.] * Acrylate polymethacrylate copolymer. [ A.C.E. ]

  43. HEAT STABILISER Choice of stabilizer depends upon : 1. Requirement of processing. 2. End use property. 3. Interacting with formulation components. 4. Meeting specification of various regulatory agencies. 5. Toxicological and environment safety.

  44. TYPES OF HEAT STABILISER 1. Lead stabiliser. 2. Tin stabiliser. 3. Barium Cadmium. 4. Cadmium zinc. 5. Lead salts and soap. 6. Organic stabiliser [ Non metals ]

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