ADDITIVES

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WELCOME
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ADDITIVES

• Polymers unsuitable for processing in pure
  unmodified form
• e.g. Polyolefins Oxidative degradation due to
  heat and pressure during processing
• PVC - Degradation at processing temperature

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ADDITIVES

• Any Substance that is added generally in small
  concentration to resins in order to
• Alter their properties
• Facilitate processing
• Change the physical, chemical or electrical
  properties of end products.
• Reduce the cost

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Requirements of Additives

• Effectiveness in their function
• Stable under processing conditions
• Stable under service conditions
• Economic
• Compatibility with Polymer Matrix
• At molecular level
• Neither Volatile nor extrude to the surface
• Neither bleed nor bloom
• Must have low vapour pressure at high temperature
• Non Hazardous, non impart taste odour

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CLASSIFICATION
Assist Processing Processing Stabilizer Lubricants - External Lubricants - Internal
Modify Bulk Mechanical Properties Plasticizer Reinforcing filler Toughening Agents
Reduce Cost Fillers Diluents extenders
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CLASSIFICATION
Surface Properties Modifier Antistatic Anti Slip Anti wear Anti block Adhesion Promoters
Optical Properties Modifier Nucleating Agents Colorants
Anti-Ageing UV Absorbers Fungicides
Others Blowing Agents Flame Retarders
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Processing Stabilizers

• Prevent degradation which is caused by
• Heat
• Oxygen
• What Happens ?
• Oxygen combines with Polymer under high temp to
  form carbonyl compounds which leads to yellow
  brown discolouration.

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Processing Stabilizers

• Primary Stabilizers Antioxidants
• Secondary Stabilizers Peroxide decomposes
• Chelating Agents Metal deactivators
• Special Stabilizers (Heat Stabilizers) for
  halogenated polymers

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Antioxidants( Primary Stabilizer )

• They inhibit or retard the oxidative degradation
  of materials at normal or elevated temperature
  during processing, storage or service due to
• Heat
• Light
• Chemical Induction
• How it works?
• It interrupt the chain reaction by combining with
  the free radicals forming a non reactive products
• (Amount 0.1 0.5)

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Effect of Oxidation

• Loss in Tensile Properties
• Discolouration i.e. yellowing,
• Increase in Brittleness
• Melt Flow Instability
• Change in appearance.
• Hardness increases.
• Loss of Gloss.
• loss of transparency.
• Cracking.
• Hindered Phenols or Aromatic Amines

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Secondary Stabilizer Peroxide decomposes

• How it works?
• Peroxides are reduced to alcohols are
  deactivated.
• EX
• Sulphur Phosphorus Compounds such as Sulphides,
  thioethers, tertiary phosphites phosphorates.

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Chelating Agents Metal Deactivators

• Prevent degradation by metal ions (impurities in
  polymers ziegler-natta redox initiators,
  fillers, pigments etc.)
• EX
• Organic Phosphines Phosphites
• Higher Nitrogenated compounds Melamine, diamine
  etc

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Heat Stabilizers

• Prevent Degradation
• Absorb Neutralize HCl gas evolved
• Prevent Oxidation reactions
• Prevent Discolouration
• Displace active substituents with stable
  substituents

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Heat Stabilizers

• Lead
• Tri Basic Lead Sulphate (TBLS)
• Dibasic Lead Sulphate (DBLS)
• Basic Lead Carbonate
• Dibasic Lead Phosphite
• Organo-tin
• Dibutyltin meleates
• Dibutyltin bis mercaptides
• Cadmium / Barium /Zinc
• Cadmium/Barium laurates
• Cadmium/Barium/Zinc Complexes

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Synergistic Stabilizer Systems

• The term Synergism is used to describe the
  combined effect of two or more stabilizers, which
  is greater than the sum of the effects of the
  individual stabilizers used in isolation.
• Effect (AB) gt Effect A Effect B

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Lubricants or Flow Promoters

• Functions -
• To reduce friction between the material and the
  processing equipment. ( Adhesive forces)
• To reduce heat wear between two surfaces either
  between the polymer molecules
• ( Cohesive forces) or between the polymeric
  material and the equipment.
• Reduces thermal degradation of the polymer.
• Modifies flow characteristics.
• Homogenous the polymer melt with other polymer
  additives.
• To prevent the plastic from sticking to the mould
  surface during processing

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Lubricants or Flow Promoters

• External Lubricants
• Internal Lubricants

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External Lubricants

• Prevent friction between polymer melt metal
  surface
• Prevent sticking to the metal parts
• They are usually high molecular compounds and
  have non-polar groups.
• They have low compatibility with the polymer but
  have high affinity for the metal surface.
• During processing they form a thin film between
  polymer melt metal surface.
• They improve surface finish gloss.
• They help to reduce melt viscosity and give a
  high output rate.

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External Lubricants

• Metal Soaps
• Metal Stearates
• Zinc Stearates
• Calcium Stearates
• Magnesium Stearates
• Hydrocarbon waxes
• Stearic Acid its calcium, lead, Ba, Cd Salt,
  Hydro carbon Esters

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Internal Lubricants

• Promotes Flow by reducing cohesive forces between
  molecular interfaces within the resin
• They are usually low molecular weight compounds,
  having polar groups.
• They function by reducing intra-molecular
  friction before and during the melt formation of
  the polymer by promoting flow and reducing melt
  viscosity of the polymeric mass.
• They also enhance polymer properties like heat
  stability, impact strength, colour clarity.

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Internal Lubricants

• Amine Waxes
• Ester Derivatives
• Glyceryl mono stearate
• Long chain esters
• Fatty Acids Amides
• Ethylene bi stear amide
• Zinc Stearates

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Selection of Lubricants

• Metal Soaps Low Compatibility with polymer, so
  used as external lubricants
• Long Chain Fatty Acids Used as Internal
  Lubricants for polar polymers.
• Long Chain di-alkyl esters Medium
  compatibility, so act as external internal
  lubricants.
• High Molecular weight paraffin wax low
  compatibility with polar polymer, so used as
  external lubricants.

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Plasticizers or softeners

• Improve process ability by reducing Tg
• These are high boiling non-volatile solvents
• Polar with a high Mol. Wt. ester type organic
  compounds.
• Reduce internal friction between polymer chain.

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Effect of Plasticizers

• Easy melt
• Improve flexibility
• Increase Softness and Flexibility.
• Improve Process ability.
• Alters Softening point, Tensile Strength,
  Elongation at break Impact.

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Types of Plasticizers

• Primary These are highly compatible with PVC
  and can be used alone.
• e.g.
• Phthalates Di-Octyl Phthalate (DOP), Di Iso
  Octyl Phthalate (DIOP)
• Phosphates Tricresyl Phosphate (TCP),
• Sebacates,
• Adipates.

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Types of Plasticizers

• Secondary These are less compatible with resin
  and are usually employed together with primary
  plasticizers.
• e.g.
• Di Octyl Sebacate (DOS)
• Adipic Acid Polyesters
• Epoxidised oil.

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Extenders

• These are not used alone as plasticizers.
• They are limited compatibility with polymer.
• In conjunction with true plasticizers it enhance
  the efficiency of plasticizers.
• Low Cost.
• It replaces the plasticizers without any adverse
  effect on polymer.
• e.g.
• Chlorinated paraffin wax,
• oil extracts.

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Selection of Plasticizers

• Solvating power
• Efficiency
• Compatibility
• Flame retardant
• Toxicity
• Low Temp. Performance
• Cost

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FILLERS

• It is used to modify mechanical properties to
  reduce the cost.

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Effect of Fillers

• The use of inert fillers can influence the
  polymer properties in the following ways -
• Increase in density.
• Increase in modulus of elasticity.
• Lower shrinkage.
• Increase in hardness.
• Increase in HDT.
• Reduction of raw material cost.
• For e.g. Calcium Carbonate,Red mud

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Fillers
Purpose Filler
Bulk Wood Flour Saw dust Wood pulp Sisal / jute Purified cellulose Mica / Rock
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Fillers
Purpose Filler
Hardeners Inorganic Pigments Mineral Powders Metallic Oxides Powder Metals Graphite
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Fillers
Purpose Filler
Chemical Resistance Glass Fibres Fabrics Synthetic Fibres Fabrics Graphite Metallic Oxides
Thermal Insulation Asbestos Ceramic Oxides Silica
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Fillers
Purpose Filler
Appearance Colour Pigments Dyestuffs Carbon Flakes Powder Metals Phosphorescent Minerals Woven Fabrics
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Fillers
Purpose Filler
Reinforcement Glass fibres Asbestos Fibbers Cellulose Fibbers Cotton Fibbers Papers Synthetic Fibbers
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Fibrous Fillers Reinforcement

• Reinforcing fillers are those which enhance the
  mechanical properties like
• Tensile Strength
• Modulus
• Hardness of a polymer compound.
• The product become stiffer and stronger than
  the base polymer.

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Fibrous Fillers Reinforcement

• Glass Fibres
• Increase (Tensile, Compressive,Flexural )
  Strength ,Increase rigidity, creep resistance
  hardness and decrease thermal expansion
  co-efficient, elongation at break.
• Minerals such as talc, calcuim carbonate, mica
  increases the compound rigidity, improve the
  temperature resistance and reduces shrinkage
  warpage.

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Coupling Agents

• These are used to increase the adhesion between
  polymer filler, fiber by covalent bonds.

Ex Methacrylato-chromo chloride used for glass
fibres Polyester resin Organosilanes are used
for PVC , ABS and PA
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Antistatic Agents

• Static charge may built up simply by friction
  with the ambient air
• Most plastics have low surface conductivity
• Static charge is not discharged fast enough
• Troublesome effects like
• Heavy contamination of plastics parts
• Shock as charge flows ( floor covering ,
• door handles)

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Antistatic Agents

• Chemicals added to plastics to reduce built up of
  electrostatic charges on the surface of materials
  
• Accumulations can occur during processing and
  at various handling points
• Static charges are dissipated by increasing the
  surface conductivity

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Antistatic Agents

• Prevent electrostatic charges mostly seen in
  PE, PP, PS, Nylons, Polyesters, Urathenes,
  Cellulosics, Acrylics Acrylonitriles
• Because of insulation properties electrical
  charge may get deposited on the surface of the
  plastics produced during processing.
• This may cause severe damage to the products
  equipments.
• It may cause accumulation of dust.
• The accumulation of static charge can be
  minimized by the use of antistatic agents.

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Antistatic Agents

• EX
• Amines
• Quaternary ammonium compounds,
• Phosphates,
• Esters,
• Polyethylene glycol esters

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Slip Anti block Agents

• Slip Reduces coefficient of friction- They are
  high molecular weight fatty alcohols
• Amount (0.05 0.2 )
• e.g. For film of 25 micron 0.01 of Oleamide

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Slip Anti block Agents

• Anti block Agents Prevent adhesion between the
  film surface
• Amount (0.05 0.2)
• e.g.
• Calcium Carbonate in PVC film
• Metal Salts
• Fatty Acids
• Natural Synthetic Waxy Materials

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Selection of Slip Anti block Agents

• Must not spoil optical properties.
• Must not interface with the adhesion ink to film.
• Must not prevent the sealing of film.
• Must be colour less
• Must be odour less
• Must be non toxic

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Nucleating Agents

• Aiding transmission of white light in Plastics
• Forms large nos. of nuclei reduces the size of
  spherulites.
• e.g.
• Sodium, Potassium, Lithium benzoates.
• Inorganic Powders Clays, Silica Flour

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Optical Brighteners

• It makes a mask over the yellowness formed during
  processing.
• Optical Brighteners are organic substance which
  absorb UV radation
• e.g.
• Benzosulphonic Sulphonamides derivatives.
• Vinylene bisbenzoxazoles.
• 4-alkyl-7-dialkyl amino coumarins.

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Colorants

• Produces varieties of coloured polymers
• Also improves
• Mechanical Strength
• Specific Gravity
• Clarity

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Colorants

• Dyes (Soluble in Polymers)
• Impart brilliant transparent colour to clear
  plastics
• Inorganic Organic
• AZOS (,180 2000C) for brightness and clarity
• Anthraquinone (AQ) Good heat transparent
  weathearibility
• (Auto tube light)

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Colorants

• Pigments (In-Soluble in Polymers)
• Inorganic
• Organic

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Colorants

• Inorganic Pigments
• Titanium dioxide - White
• Cadmium sulphide - Yellow orange
• Lead chromate - Yellow orange
• Chromium oxide - Green
• Organic Pigments
• Benzidese Yellow orange
• Copper phthalocyanine -Blue
• Chlorinated copper phthalocyanine
• Aniline black - BLack

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Selection of Colorants

• Heat Stability
• Disperse ability
• Light fastness
• Chemical Inertness
• Opacity or transparency

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Anti-Ageing Additives

• Deterioration by Atmospheric
• Radiation
• Temperature
• Oxygen
• Water
• Micro-Oranisms
• Gases etc

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Ultraviolet Light Absorbers

• Detected by
• Loss in Tensile Properties
• Discolouration
• Brittleness

• EX
• Black in any form Carbon Black, Black dye,
  Black paints
• Benzophenones for PE, Polyesters
• Benzotriazoles for PS, Polyesters

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Impact Modifier

• To enhance the impact properties of certain
  brittle polymers so as to use in the field.
• e.g.
• Chlorinated polyethylene ,EVA are used for PVC.
• SBR is used for polystyrene material.
• EPDM is used for PP ( Bumpers)
• Acrylic rubbers for Poyamides

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Flame Retardants

• Plastics Fire free radical formation combines
  with Oxygen CO CO2
• Application Automobile, Aerospace,
  Electrical,Transportation,Building,Furniture,
  TV cabinet

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Flame Retardants

• Prevent Combustion by
• Insulate
• Creating endothermic cooling reaction
• Coating the product

• EX - Aluminium trihydrate ( Nylon)
• Antimony trioxides (ABS)
• Chlorinated Paraffin
• Zinc borate
• Halogen Compounds
• Phosphorous acid esters ( PA,POM,FRP)
• Nitrogen Compounds

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Blowing Agents

• Blowing agents are also known as foaming agents.
  Upon heating liberate Gas
• Are used to produce porous polymers i.e.
  cellular/foam plastics.

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Blowing Agents

• Physical Blowing agents Nitrogen CO2 inert
  gas- Low cost, No solid residue
  Trichlorofluromethane PU foam
• Pentane and Heptane - PS foam
• Chemical Blowing agents High temp, Azo
  Dicarbonamide decompose on heating to produe free
  radicals and N2 gas

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Blowing Agents

• Blowing agents are also known as foaming agents.
  Upon heating liberate Gas
• Are used to produce porous polymers i.e.
  cellular/foam plastics.

• EX
• Ammonium bi carbonates
• Sodium bi carbonates
• Azo Di carbonamide
• Azo bis formamide
• N-nitrogen Compound
• Sulfonyl Hydrazides

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Master Batches,Additives Reinforced Compounds
Material Supplier
Master Batches S.C.J. plastics Ltd. New Delhi www.scjindia.com
Master Batches Reinforced Compounds Aalekh Polymers (P) Ltd. 8/30, Kirti Nagar New Delhi 15 Ph. No. 25195193
Polymer additives Fine organics Bombay 022-25116900-02
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