Transcript PLASTICS MATERIALS - CEG

Solid Materials
Metals
Plastics
Thermo -settings
Commodity
Ceramics
Thermoplastics
Engineering
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Specialty
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PLASTICS
THERMOPLASTICS
• Linear or slightly branched
polymer –
addition/condensation
• Repeated softened at
elevated temperature and
solidified on cooling
• No chemical changes occur
• Molecules are held by
secondary forces
THERMOSETTING PLASTICS
• Do not form linear chain –
forms 3 –dimensional
structure
• Hard and infusible and
cannot be softened without
decomposition
• Molecules are held by
primary forces.
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FAMILIES OF POLYMER MATERIALS
SEMI-CRYSTALLINE
(Structured)
THERMOPLASTICS
(Can be melted)
AMORPHOUS
PLASTICS
(Random)
THERMOSETS
(Cannot be melted)
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Polymers are a large class of materials consisting of many small molecules (called
monomers) that can be linked together to form long chains, thus they are known
as macromolecules
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Amorphous Vs Crystalline
An amorphous solid is formed when the chains have little orientation
throughout the bulk polymer. The glass transition temperature is the
point at which the polymer hardens into an amorphous solid. This term
is used because the amorphous solid has properties similar to glass.
In the crystallization process, it has been observed that relatively
short chains organize themselves into crystalline structures more readily
than longer molecules.
Therefore, the degree of polymerization (DP) is an important
factor in determining the crystallinity of a polymer. Polymers with a high
DP have difficulty organizing into layers because they tend to become
tangled
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Thermoplastics From melt to solid
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Various Thermoplastics
PI
Specialty
Polymers
PSU PTFE
LCP
PES
HPPA
PPSU
Engineering
Polymers
PC
PPO
Commodities
ABS
PMMA
PA
POM
PBT
TPE
PP-GF
PS
PVC
SAN
AMORPHOUS
PET
PE-UHMW
PP
PE-LD
PE-HD
CRYSTALLINE
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Why Use Thermoplastics?
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Increased performance
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Corrosion resistance
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Weight reductions (specific strength & stiffness)
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Cost reduction!
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Parts consolidation & net shape formation
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Process elimination (painting, machining, assembly)
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Economics of injection molding
Properties can be altered to suit the needs
Good strength/weight ratio
Tough & durable
Non toxic
Easy processability
Chemical/Moisture Resistant
Fire retardant
Do not rust/corrode.
Resistant to microbes
Attractive colours
Good weatherability
Practically maintenance free
Reusable / Recyclable
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Low Density Polyethylene
(LDPE)
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STRENGTHS
LIMITATIONS
• Susceptible to environmental stress
cracking
• Very low cost
• Excellent chemical resistance
• Very good process-ability
• High impact strength at low
temperature
• Low strength, stiffness and maximum
service temperature
• Excellent electrical insulating properties
• High gas permeability, particularly carbon
dioxide
• Very low water absorption
• FDA compliant
• Can be transparent in thin film form
• Poor UV resistance
• Since it is non-polar, electrical properties are
almost independent of temperature and frequency
• Tg is well below the room temperature
• Highly flammable
• High-frequency welding and joining
impossible
• Poor scratch and abration resistance
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Processability
General information
The most common process used for LDPE is extrusion (tubes, blow and cast films,
cables, ...). LDPE can also be processed by injection molding or rotomolding.
Extrusion
Melt temperature : 180-240°C
Higher melt temperatures are needed for extrusion-coating (280-310°C).
A three zone screw with a L/D ratio of around 25 is recommended.
Injection molding
Melt temperature : 160-260°C
Post mold shrinkage lies between 1.5 and 3.5 %.
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Applications
Key performances
Packaging
Pharmaceutical and squeeze bottles
•Low cost
•Processability
•Flexibility
•Low cost
•High flexibility
•Processability
Caps and closures
Tamper evidents
Liners
Trash bags
Films for food packaging (frozen, dry goods ...)
Laminations
•Low cost
•High flexibility
•Processability
Consumer goods
•Low cost
•Processability
•Flexibility
Housewares
Flexible toys
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Applications
Key performances
Agriculture
•Low cost
Agricultural films
•Good mechanical properties
•Processability, excellent drawdown
Pipes & Fittings
•Low cost
Water pipes and hoses
•Excellent chemical resistance
•Very low water absorption
•Processability
Wiring & Cables
Sub-conductor insulators
Cable jacketing
•Low cost
•Good electrical insulating properties
•Processability
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Linear Low Density Polyethylene
(LLDPE)
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Strengths
Limitations
• Higher tensile strength than LDPE
• Lower gloss than LDPE
• Higher impact and puncture resistance
than LDPE
• Narrower temperature range for heat
sealing than LDPE
• Lower thickness films can be blown
compared to LDPE
• Lower processability than LDPE
• Susceptible to stress cracking
• Improved sealability
• Lower stiffness than polypropylene
• Excellent chemical resistance
• High mold shrinkage
• Very good processablity
• Poor UV resistance
• High impact strength at low temperature
• Low heat resistance
• Excellent electrical insulating properties
• High-frequency welding and joining
impossible
• Very low water absorption
• High environmental stress crack
resistance
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General information
The most common process used for LLDPE is extrusion (tubes, blow and cast films,
cables, ...). LLDPE can also be processed by injection molding or rotomolding.
Extrusion
Melt temperature : 205-260°C
A three zone screw with a L/D ratio of around 25 is recommended.
Injection molding
Melt temperature : 160-260°C
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Applications
Key performances
Packaging
Bags and pouches
Films for food packaging (frozen, dry
goods)
•Low cost
•High flexibility
•Processability
Agriculture
Agricultural films
•Low cost
•Good mechanical properties
•Processability, excellent Drawdown
Pipes & Fittings
Water pipes
•Low cost
•Excellent chemical resistance
•Very low water absorption
•Processability
Wiring & Cables
Cable jacketing
Cable insulators
•Low cost
•Good electrical insulating properties
•Processability
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Applications of LDPE & LLDPE
Green House
Cable Sheathing
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Bottle Caps
Pouch
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High Density Polyethylene
(HDPE)
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Strengths
Limitations
•Higher notched impact strength than other PE
•Higher wear resistance than other PE
•Not melt processable
•Higher energy absorption capacity at high stress
rates than other PE
•Higher Cost than PE
•Higher heat deflection temperature than other PE
•Higher stress crack resistance than other PE
•Very low water absorption
•FDA compliant
•Good thermal stability
•Tg is well below room temperature
•High tensile strength, stiffness, creep resistance,
abrasion resistance than LDPE
•Non-polar in nature
•Very good chemical resistance
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General information
PE-UHMW is not melt processable, because of its extremely high viscosity. It can be
processed by ram extrusion and compression molding.
Applications
Key performances
Engineering
Linings of bunkers, silos and hoppers
Excellent sliding properties
High wear resistance
High toughness
Conveying applications (bottling,
packing and transport equipment)
Low friction with metal
High wear resistance
High impact strength
Noise reduction
Pump casings
Good corrosion resistance
Excellent chemical resistance
Practical heat resistance
Abrasion resistance
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Polypropylene
(PP)
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Strengths
•Low cost
Limitations
• Poor resistance to UV, need to
•Good chemical resistance against most
be stabilized
inorganic acids, alkalis, and salts
• Embrittles below -20°C
•Good resistance to environmental stress
• Low upper service temperature,
cracking when in contact with alcohols, esters,
detergents, or polar hydrocarbons
90-120C
• Attacked by highly oxidizing
•Very good fatigue resistance
acids, swell rapidly in chlorinated
•Very low density
solvents and aromatics
•Excellent dielectric properties
•More rigid than PE and retains mechanical
properties at elevated temperatures
• Heat-ageing stability is adversely
affected by contact with metals
• Post moulding dimensional
•Mechanical and electrical properties unaffected
changes due to crystallinity
by submersion in water
effects
•Can be FDA compliant
• Limited impact resistance
•Good resistance to steam sterilization
• Low scratch resistance
•Excellent hinge characteristics
• Poor paint adhesion
•Can be joined by hot-gas, hot-tool, induction, or
friction welding
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General information
These resins are not hygroscopic and may be used as received without need for
drying.
At temperatures above 220ºC, EVA resins can evolve toxic fumes.
Injection molding
Melt temperature : 180 - 300°C
Mold temperature : 20 - 60°C. Higher the mold temperature then better the surface
gloss.
High injection pressure and speed are recommended.
Extrusion
A three-zone screw with a total L/D ratio of 20-25 is generally recommended.
Melt temperature is, generally, in the overall range of 240-270ºC .
Blow molding
Melt temperature should lie between 190 and 220°C.
Mold temperature should lie between 20 and 40°C.
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Applications
Key performances
Packaging
Flexible packaging (Food and
confectioneries, Tobacco, Clothin ...)
Low cost
Good barrier properties
Good processability
Good puncture resistance
Rigid packaging (crates, bottles, pots ...)
Low cost
Good processing stability
High strength
Good surface finish
Caps and closures for beverage and
cosmetic applications
Low cost
Good processing stability
High strength
Good surface finish
Fibers / Textiles / Carpets
Nonwovens
Film tapes
Strapping ...
High flexibility
Good resistance to rupture
Good chemical resistance
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Applications
Key performances
Health Care
•Sterilization resistance
Syringes
•Good chemical resistance
•Transluscent
Household products / Consumer goods
•Good cost to impact balance
Transluscent parts
•Excellent processability
•Transluscent
Housewares
Furniture
Appliances
Luggage
Toys
•Good cost to impact balance
•Excellent processability
•Long-term use
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Polyvinyl Chloride
(PVC)
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Strengths
Limitations
Rigid PVC
•Low cost
•Difficult to melt process
•High stiffness
•Becomes brittle at 5°C (when not
•Intrinsic flame retardant
modified with impact modifiers and/or
•Suitable for transparent applications
processing aids)
•Better chemical resistance than plasticized
•Limited solvent stress cracking
PVC
resistance
•Good electrical insulation properties
•Low continous service temperature of
•Good vapour barrier properties
50°C
•FDA compliant
•Good dimensional stability at room
temperature
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General information
Thermal stabilization is required for processing rigid PVC, otherwise material may
decompose during processing.
PVC is sensitive to the thermal history and the window of processing temperatures is
quite small.
Drying before processing is highly recommended, moisture rate should be lower than
0.3%.
Injection molding
Melt temperature should lie between 170 and 210°C.
Mold temperatures of 20 to 60°C are more suitable.
Mold shrinkage lie between 0.2 and 0.5%.
Screw with an L/D ratio of 15 to 18 is recommended.
Extrusion
Extrusion temperatures are 10-20°C below injection molding temperatures in order to
avoid premature thermal degradation.
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Applications
Key performances
Electrical
Insulation pipes
Jacketing
Electricity distribution boxes
Switches
Transparent distributor box housings
Plug housings
Battery terminals
•Low cost
•Good electrical properties
•Stiffness
•Inherent flame retardant
Engineering
Pressure pipes
Ventilation ducts
Thermostat housings
Fittings
Pipe connections
Claddings
Ventilators
•Low cost
•Versatile performance profile
•Stiffness
•Good chemical resistance
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Applications
Key performances
Building and Construction
Waste water pipes and fittings
Grating covers
Fencing
Decking
Siding
Drain pipes
Roofing sheets
Sanitary installations
Window profiles
Fascia boards
•Low cost
•Processability
•Stiffness
•Flame retardant
Consumer goods
•Low cost
Toys
Vases
Cases
•Stiffness
•Processability
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Applications
Key performances
Packaging
Disposable pots
Spice and cream containers
Ball point pen cases
Blisters
Capsules
Trifolds
Bottles for vegetable oil, juices, wine or non-food
packaging (cosmetics ...)
•Low cost
•Practical stiffness
•Transparency
•Processability
•Good chemical resistance
Pipes & Fittings
•Low cost
•Practical stiffness and
impact strength
Pipes Fitttings
•Good chemical resistance
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Strengths
Limitations
Flexible PVC
•Properties can change with time, due to
•Low cost
plasticizer migration
•Good resistance to UV
•Tends to degrade at high temperatures
•Flexible
•Attacked by ketones; some grades
•High impact strength
•Good resistance to acids, alkalis, oils
and many corrosive inorganic chemicals
Good electrical insulation properties
•Non-flammable
•Easier to process than rigid PVC
•Versatile performance profile
swollen or attacked by chlorinated and
aromatic hydrocarbons, esters, some
aromatic ethers and amines, and nitro-
compounds
•Non suitable for food contact with some
plasticizers
•Lower chemical resistance than rigid PVC
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General information
Drying before processing is highly recommended, moisture rate should be lower
than 0.3%.
Injection molding
Melt temperature should lie between 170 and 210°C.
Mold temperatures of 20 to 60°C are more suitable.
Mold shrinkage lie between 1 and 2.5%.
Extrusion
Extrusion temperatures are 10-20°C below injection molding temperatures in order
to avoid premature thermal degradation.
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Applications
Key performances
Electrical
Cable and wire insulation
Plugs
Cable jackets
Sockets
Cable heads
Distributors
Flexibility
Good electrical properties
Low cost
Engineering
Gaskets
Stuffing boxes
Pipes
Hoses
Coatings
Protective caps for pipes.
Flexibility
Versatile performance profile
Low cost
Building and construction
Seals for windows and doors
Swimming bath linings
Flexibility
Floor and wall coverings
Good weathering resistance
Roofing
Low cost
Doorstops
Flame retardant
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Wire coverings
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Applications
Key performances
Consumer Goods
Toys
Handbags
Tablecloths
Cases
Flexibility
Good weathering resistance
Low cost
Processability
Sports & Leisures
Balls
Ski sunglasse seals
Inflatable dinghies
Flexibility
Good weathering resistance
Low cost
Footwear
Shoe soles
Boots
Flexibility
Good weathering resistance
Low cost
Gardening
Garden hoses
Flexibility
Good weathering resistance
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Low cost
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Applications
Key performances
Automotive
Car body seals
Dashboard skins
Artifical leather seats
Sun visors
•Flexibility
•Good weathering resistance
•Low cost
Healthcare / Medical
•Flexibility
Blood storage bags
Drainage tubes
•Hemocompatible
•Low cost
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Types of Profiles :
Hollow Profiles
Foam Profiles
Doors :
Aluminium Frame + Hollow
Profile
PVC Frame + Hollow Profile
PVC Frame + Foam Sheet
Door Frame
Windows
Sliding
Casement
Single Glazing
Double Glazing
Partitions
False Ceiling
Miscellaneous
(Viz... Kitchen Cabinets etc.)
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Versatility of PVC
From
Footwear…..
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Polystyrene
(PS)
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Strengths
Limitations
•Brittle at room temperature
•Low cost
•Transparent
•Poor mechanical properties above 70°C
•High stiffness
•Good processability
•Poor chemical resistance, especially to
organic solvents
•Good electrical properties, low
•Susceptible to UV degradation
•Good dimensional stability
dielectric loss
•Excellent resistance to gamma
•Highly flammable
radiation
•Limited resistance to organic solvents, when
compared to polyolefins.
•FDA compliant
•Low moisture absorption
•Low mould shrinkage
•Very low thermal conductivity
•Possesses tendency to stress cracking
Low creep strength under repeated stress
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High Impact Polystyrene
Strengths
Limitations
Tougher than PS crystal
Reduced transparency compared to PS crsytal
Low cost
Reduced electrical properties compared to PS
crystal
Good dimensional stability
Poor chemical resistance, especially to organic
solvents
Good processability
Good electrical properties, low
dielectric loss
Susceptible to UV degradation
Excellent resistance to gamma
radiation
Highly flammable and toxic smoke
FDA compliant
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General information
Crystal polystyrene can be processed by every conventional technique used for
thermoplastics.
Drying is normally not necessary. But if necessary (high transparency and high gloss
required), the product can be dried for 2 hours at about 80°C.
Injection Molding
A melt temperature of 180-280°C is recommended.
Generally, mold temperature should lie between 30 and 50°C. For thin wall objects
moulded at short cycle times it could be useful to cool down the mould down to
10°C.
Mold shrinkage lies between 0.4 and 0.7% depending on the grade used.
Extrusion
Grades with a high viscosity are suitable for extrusion.
A melt temperature of 180-220°C is generally used.
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Applications
Key performances
Packaging
Food packaging
(dairy packaging, meat trays, egg cartons,
fruit and vegetable trays)
Consumer packaging (cassettes and CD
shell and covers, jewel box ...)
Industrial packaging (small foamed shapes
...)
Low cost
Ease of process and decoration
Food contact approvals
Possibility to be produced by lots
Recyclability of the material
High stiffness
Low cost
Ease of decoration
Ease of process
Possibility to be produced by lots
Recyclability
Ease of process
Low cost
Recyclability
Possibility to be produced by lots
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Applications
Key performances
Consumer Goods
Low cost
Processability
Available in a wide range of colors
Low density
Toys
Cutlery
Disposables
(cups, forks, knives, spoons,
plates…)
Shower stalls
Door lights
Envelope frames ...
Low cost
Recyclable
Processability
FDA compliant
Low cost
Ease of process
Possibility of printing and design
Safety when broken (contrary to glass for
shower stalls for instance)
Optics
Light diffusers
Transparency
Low cost
Processability
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Stiffness
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POLYMETHYLMETHAACRYLATE (PMMA)
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Strengths
Limitations
•Outstanding transparency
•Poor impact resistance
•Excellent UV resistance
•Limited heat resistance (80°C)
•High color brightness and stability
•Limited chemical resistance, attacked
by organic solvents
•Surface hardness
•Poor wear and abrasion resistance
•Half the weight of glass
•Cracking under load possible
•Good dimensional stability
•Good insulating properties
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General information
Pre-drying is not necessary if a vented cylinder is used but if a normal cylinder is
used then PMMA must be processed dry and it is advisable to pre-dry the granules
for up to 8 hours at 70-100°C. Surface defects and blisters will form if damp
granules are processed.
Injection Molding
Melt temperature : 200-250°C
Mold temperature : 40-80°C
High injection pressures are needed because of poor flow properties and it may be
necessary to inject slowly to get the correct flow.
Extrusion
Extrusion temperature : 180-250°C
A degassing screw with an L/D ratio of 20-30 is recommended.
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Applications
Key performances
Building & Construction
Windows
Port-holes
Domes
High transparency
UV resistance
Surface hardness
Optics
Sunglasses
Diffuser panels
Watch glasses
Optical properties
Transparency
UV resistance
Surface hardness
Good optical performance
Resistance to weathering
Hardness
Chemical resistance
High clarity
Lower weight than glass
High surface quality
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Applications
Key performances
Automotive
Rear lights
Indicators
Optical properties
Colorability
Weathering resistance
Dashboard covers
High transparency and clarity
Scratch resistance
Chemical resistance
Electrical
Lamp covers
Transparency and excellent optical properties
Processability
Chemical resistance
Packaging
Blister packaging
Transparency
Hardness
Thermoformability
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Applications
Key performances
Automotive
Pens
Transparency
Gloss
Goods processability
Plates
Salad bowls
Resistance to greases
FDA compliant
Good surface finish
Healthcare / Medical
Toothbrushes
Good processability
Transparency
Chemical resistance
Blood sample tubes
Diagnostic dishes
Optical clarity
Biocompatible
Resistance to sterilization
Industrial
Point-of-purchase displays
High versatility
Good compatibility with other materials
Good surface finish
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ETHYLENE VINYL ACETATE (EVA)
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Strengths
•Highly flexible , even at low temperatures
(-25°C)
•Highly compatible with a lot of elastomers,
TP and other materials (SBr, EPDM, TPE,
PE, PVC, asphaltum ...)
•Better tear resistance than LDPE
•Excellent resistance to environmental
stress cracking
Limitations
Poor heat resistance
•Reduced barrier properties
compared to LDPE
•Attacked by polar solvents,
hydrocarbons, oxydants and strong
acids
•Reduced creep resistance,
compared to LDPE
•FDA compliant
•Good UV and ozone resistance
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General information
These resins are not hygroscopic and may be used as received without need for
drying.
At temperatures above 220ºC, EVA resins can evolve toxic fumes.
Injection molding
Experience has shown screws normally used for injection molding of low density
polyethylene to be satisfactory.
Melt temperature : 150-200°C
Mold temperature : 15-40ºC
Extrusion
A three-zone screw with a total L/D ratio of at least 20 is recommended.
Melt temperature is, generally, in the overall range of 95-205ºC .
The melt temperature depends upon the melt index of the resin, the % vinyl acetate
and the part configuration.
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Applications
Key performances
Packaging
•High flexiblity
Stretch film for shrink wrapping
•Good tear resistance
•FDA compliant
•Good sealability
Sealable layer in multilayer food packaging
•Flexibility
•FDA compliant
Personal safety/ Protection equipment
•High flexibility
Flexible gloves
•Good resistance to rupture
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•Good chemical resistance
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Applications
Key performances
Automotive
Sound proofing
•Good sound absorption
•Good adhesion with many substrates
Footwear
Soles (EVA foam)
•Good impact absorption
•Good adhesion with many substrates
Wiring & Cables
Wire coating
•Good adhesion with many substrates
•Highly flexible
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Seals, Toys, Helmet Parts
Corrugated Tubes
Shoe Components
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