Seminar #1
Flexible PVC Technology - Flexible (PLASTICIZED) PVC Seminar
Factors Affecting Stabilizer Choices for Flexible PVC Applications.
Formulating, Compounding, Processing
Reference Index:
Stabilization of Flexible PVC (Non-Lead)
Stabilizer Performance in Flexible PVC (non-lead)
End-Use, and Lifetime of Product:
PVC Resins-- Characteristics (incl. VC/VA copolymers)
Suspension (& Bulk) Emulsion (Dispersion)
Extrusion Plastisols / Organosols
Calendering Coating, Casting
Molding (Injection) Molding (Rotational, Slush)
Fluid Bed Dipping
Important parameters:
K-Value, Particle morphology, Plasticizer Dry-up, Plastisol viscosity, Zinc sensitivity, Electricals.
Primary Secondary Specialty
Phthalates Cl- Paraffins (FR) Epoxy Oils & Esters
Trimellitates Hydrocarbon extenders Phosphates (FR)
Adipates Polymeric Esters
Azelates
Sebacates
(Alcohol Choices: Branched or Straight-chained C-8, C-9, C-10’s)
Plasticizer Efficiency (vs. 50 phr DOP): Fusion, Solvation, Gellation, Tensile,
Elongation, Clarity, Viscosity (initial & aged), Air release, Low Temperature
Flexibility (cold-crack), Volatility (automotive fogging), Permanence (oil & water extraction & spew).
Use Levels: Shore A&D Hardness.
Effects upon heat stability and special stabilizer needs (Phosphates & Cl-Paraffin)
Ground, Precipitated Calcium Carbonate (most commonly used)
Particle size, Distribution (Top size and Fines)
Affects tensile, elongation, viscosity
Use level (capacity of resin/plasticiser system to accommodate)
Affects above properties, and hardness, abrasion resistance, and stabilizer optimization (Zn levels)
Other fillers used:
Silicates: Clay, Kaolin, Talc, and (formerly) Asbestos
Barytes - Ba sulfates
ATH - Aluminum Trihydrate (FR)
Al/Mg Minerals Ultracarb (FR)
Stearic acid, Stearyl Alcohol, Ca Stearate, EBS, GMS, GMO, and other Fatty Esters.
Oxidized PE wax, Paraffin wax, Mineral oil
Concerns: Effects upon Clarity, Heat sealing, Printability.
Inorganic, Organic Types
Concerns: Heat stability, U.V. stability, Oxidative stability, Chemical resistance.
Specialty pigments:
Metallics (Al, Cu, Au, Bronze powder) - Stabilizer adjustments
Fluorescents - Stabilizer choice
Endothermic (Na carbonate/ citric acid blends)
Exothermic Azodicarbonamide-- (most commonly used)
Factors affecting blowing temperature and rate of gas release:
Particle size, metal carboxylate (Zn, K, Pb, Ba, Sn) activation retardation.
Other exothermic CBA’s: OBSH, TSH
Wetting Agents (Viscosity control)
Anti-fog Agents (Film)
U.V. Absorbers
Biocides
Antistatic Agents
Dryblend -------------- (direct) -------------->> Powder molding
Fluid bed
Extrusion (incl. foams)
Compounding extrusion -- (direct feed) --> Calendaring
Supported
Unsupported
Foams
Pellets -------------------------------------------> Injection Molding
Extrusion
Banbury (Melt Mixer) ---> 2 Roll Mill ---> Calendaring
Plastisols & Organosols
Low Shear Mixer (Planetary or Hobart type) or...
High Shear Mixer ( Cowles Dispersion)
Vacuum De-aeration for both --------------> Coating, Casting (Knife, Reverse Roll)
Molding (Rotational, Slush)
Dipping
Foams on all.
Processing: (All can be foamed)
Extrusion (Mostly single screw, 20-30:1 L/D)
Vented - for Dryblends
Non-vented - for Pellets
Profiles, Tubing, Hose, Film, Sheet, Medical Products
Calendaring (Inverted “L” or “Z” types)
“Supported” (Paper/ Fabric Substrates) Film & Sheet
Wall covering, Upholstery, Automotive, etc.
“Unsupported” Film & Sheet
Pool & Pond Liners Roofing Membranes, Shower Curtains, Flooring, Molding
Misc. Specialties, Toys, Shoes & Soles, Powder (rotational) Molding for Automotive Instrument Panels
Powder Fluid Bed Coating
Dishwasher and Refrigerator Racks & Shelving, Closet Shelving
Plastisols (Pastes) and Organosols
Coating & Casting
Film, Flooring, Fabric Coating, Paper Coating, Metal Coating
Molding (Rotational, Slush)
Balls, Inflatables, Dolls, Boots, Prosthetics, Novelties (i.e. Lures)
Dipping
Tool Handles, etc.
Vinyl Solutions (in MEK, etc.)
Homopolymer and Copolymer (for adhesion)
Baked Coil Coating (Appliances), Can Lining, Aluminum Siding
Vinyl Emulsions (Latices)
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Building & Construction... - Pipe & Fittings (Potable water, sewer, irrigation, telephone duct, fiber optic cable duct, drain/waste/vent, spiral wound large diameter culvert, chemical and food processing piping, fire sprinkler piping) - Siding, Gutters, Downspouts - Window Profiles - Fencing - Decking/Docking - Flooring & Cove Base - Wall Covering - Wire & Cable - Single Ply Roofing Membrane - Landfill Liners
Transportation... - Instrument Panels, Dashboards - Auto, Mass Transit & Aircraft Interiors & Seating - Under Hood Wiring - Under Car Abrasion Coating - Floor Mats - Arm Rests - Foamed Gaskets - Window Trim - Body Side Molding - Convertible rear windows (Obsolete! but big years ago!)
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Electronic/Appliances... - Keyboards - Component Housings - Electrical Cord Jacketing - Fiber Optic Sheathing - Floppy Disk Jackets - Various Components in Phone Systems, Power Tools, Washers, Refrigerators, Air Conditioners, Computers.
Medical... - Blood Bags, and Tubing - Catheters - Surgical Gloves, and Sheeting - Prosthetics - Single Dose Medication Packaging
Packaging... - Meat and Produce Film - Jar Lid Gasketing (Foamed Plastisol) - Clear Blister Pack Sheet (Thermoformed) - Clear & Opaque Bottles
Home & Leisure... - Garden Hose - Toys, Dolls, Inflatables - Shoe Soles - Fishing Lures - Vinyl Coated Metal Racks & Shelving - Boat & Dock Pads - Tarpaulins - Credit Cards (copolymer) - Patio Furniture, Fabric, Strapping - Shower Curtains - Swimming Pool Liners |
Stabilization of Flexible PVC (Non-Lead)
Typical Stabilizer Components, and Their Functions:
Barium Nonyl Phenate (& overbased versions)
Long term stability in mixed-metal systems, Balances Zinc Component.
Cadmium Carboxylates (octoate, neodecanoate, etc.)-- Usage disappearing.
Early & mid-range color hold, U.V. stability
Zinc Carboxylates (octoate, neodecanoate, etc.)
Good early color, poor long term stability due to “Zn burning” caused by buildup of ZnCl2, a strong Lewis acid and degradation accelerator.
Also a good “Azo” activator. Balanced usage necessary. Higher filler contents benefit from higher zinc levels.
Calcium Carboxylates
Long term stability (not as good as Ba). Offsets “Zn burning” in nontoxic systems.
Beta-di-ketones (& newer organics via Ackros)
Used as Cd replacements in Ba/Zn and Ca/Zn systems - very costly!
Alkyl/Aryl Phosphites (DPIOP, PDDP, TNPP, PE Phosphites)
Heat stability and 2ndary AO (peroxide decomposer)
U.V. stability
ZnCl2 de-activation (chelation?)
Polyols (PE,etc) & Phenolic AO’s
Zeolites & Hydrotalcites
Very efficient HCl scavengers, works well with mixer metal & tin systems.
Epoxys- Soya, Linseed Oils, Tallate esters
Good HCl scavengers, adds to “synergy” of most mixed metal systems.
Alkyltin Carboxylates, Mercaptoesters
Specialty uses ( Ultra high clarity, pigment considerations)
Mixed Solvents & “compatiblizers” (Polar to non-polar types, surfactants)
Used at a minimum to obtain stable blends having good shelf life through freeze/thaw/heat cycles.
Goal is to strive for minimum volatility and maximum active ingredients concentration that is shelf-stable.
Stabilizer Performance in Flexible PVC (non-lead)
Factors of Concern / During Processing:
Color Hold, including Regrind use
Plateout Control ( Emboss Retention, Surface Integrity)
Lubricity/ Rheology (Especially with high speeds & thin gauges)
Plastisol Viscosity & Air Release
Low shear- Brookfield
High shear- Sievers
End-Use, and Lifetime of Product:
Clarity
U.V., Outdoor Durability
Long Term Heat Aging (i.e. 150-200 deg. F for weeks)
Toxicity
Electricals
Stain Resistance (Sulfide, Urethane, U.V. Absorber, Antioxidant)
Odor
Moisture Resistance - Hydrolysis ( see also Clarity)
Heat-sealing, Printability
Volatility (Automotive “Fogging”)
The above factors need to be considered when designing the stabilizer(s) for specific products and processes, or when selecting an existing stabilizer for that product or process.