Plastics : Plastic granules - The raw material of the plastic industry -

Plastic granules are small pellets of plastic (like tiny beads) that are melted to make plastic products. 

What are pellets (granules):

Physical Characteristics:

• Size: 2-5mm typically
• Shape: Cylindrical, oval, or spherical
• Form: Solid, uniform pieces
• Surface: Smooth or slightly rough
• Color: Natural (translucent) or colored

Types Virgin Granules:

• They are brand new material
• They have vever been processed before
• They are of a higher quality
• They are more expensive
• They have better properties

Recycled Granules:

• Made from reprocessed plastic
• Previously used
• Has a variable quality
• Has a lower cost

Common Materials:

• PE(Polyethylene):  milk jugs and shopping bags
• PP(Polypropylene):  food containers and car parts
• PS(Polystyrene): disposable cutlery 
• ABS(Acrylonitrile Butadiene Styrene): LEGO bricks and computer keyboards
• PVC(Polyvinyl Chloride): pipes and window frames
• PET(Polyethylene Terephthalate):  soft drink bottles
• Nylon(Polyamide):  fishing line and clothing

DETAILED BREAKDOWN:

PE (Polyethylene) Simple Uses:

• Shopping bags
• Milk jugs
• Toys
• Food containers
• Types: HDPE (high density), LDPE (low density)
• Processing temp: 160-240°C
• Common issues: UV sensitive
• Properties: chemical resistance, Flexible, Waterproof, Easy to process

PP (Polypropylene) Simple Uses:

• Food containers
• Car parts
• Furniture
• Bottle caps
• Processing temp: 200-250°C
• Strong but flexible
• Good hinge properties
• Properties: fatigue resistance, Chemical resistant, Lightweight, Heat resistant

PS (Polystyrene) Simple Uses:

• Disposable cutlery
• Food packaging
• Insulation
• Processing temp: 180-280°C
• Types: GPPS (General Purpose), HIPS (High Impact), EPS (Expanded)
• Properties: Rigid, Clear (GPPS), Brittle, Low cost

ABS (Acrylonitrile Butadiene Styrene) Simple Uses:

• LEGO bricks
• Computer keyboards
• Car parts
• Appliance housings
• Processing temp: 220-260°C
• More expensive than basic plastics
• Good dimensional stability
• Processing temp: 220-260°C
• More expensive than basic plastics
• Good dimensional stability
• Properties: High impact strength, Good surface finish, Easy to paint, Tough

PVC (Polyvinyl Chloride) Simple Uses:

• Pipes
• Window frames
• Floor covering
• Cable insulation
• Processing temp: 160-180°C
• Needs stabilizers
• Types: Rigid PVC, Flexible PVC (with plasticizers)
• Properties: Fire resistant, Weather resistant, Durable, Chemical resistant

PET (Polyethylene Terephthalate) Simple Uses:

• Drink bottles
• Food containers
• Fiber for clothing
• Packaging films
• Processing temp: 260-290°C
• Moisture sensitive
• Needs drying before processing
• Properties: Crystal clear, Strong, has a gas barrier, food safe

Nylon (Polyamide) Simple Uses:

• Gears
• Bearings
• Clothing
• Fishing line
• Types: Nylon 6, Nylon 66, ...
• Processing temp: 230-290°C
• Moisture sensitive
• Expensive compared to basic plastics
• Properties: Very strong, Wear resistant, Good bearing properties, Heat resistant

Key Processing Considerations:

• Specific drying
• Different temperatures
• Different pressures
• Different mold temperatures
• Different cooling times

Features to Compare:

Cost of manufacturing: 

• Low: PE, PP, PS
• Medium: PVC, PET
• High: ABS, Nylon

Ease of Processing:

• Easy: PE, PP
• Medium: PS, PVC
• More Difficult: PET, Nylon

Durability:

• High: Nylon, ABS
• Medium: PP, PVC
• Lower: PS

Heat Resistance:

• High: Nylon, PP
• Medium: ABS, PVC
• Lower: PS, PE

Physical properties to consider :

• Melt Flow Rate
• Density
• Moisture content
• Bulk density
• Particle size distribution

Processing (to consider):

• Melting temperature
• Drying requirements
• Processing window
• Heat stability
• Flow characteristics

Storage & Handling (to consider):

• Dry environment
• Sealed containers
• Away from sunlight
• Controlled temperature ntrolled
• Protection from moisture 

Handling(to consider):

• Use clean containers
• Avoid contamination
• Use proper labeling
• FIFO inventory
• Regular quality checks

Pre-Processing Drying(to consider):

• Some need drying
• Some need specific temperatures
• Some are moisture sensitive

Mixing parameters(to consider):

• Additives, with color, with other materials, Blend ratios, Mixing time

Common processing issues:

• Moisture contamination
• Poor flow of melted plastic
• Inconsistent size
• Dust contamanation
• Bridging in hopper, occurs when plastic material forms an arch or above the hopper outlet where granules go, preventing material flow despite space below

Quality Issues(to consider):

• Contamination
• Color variation
• Property variation
• Degradation of material
• Mixed with foreign materials