Common Plastic Types and Manufacturing Processes

Thermoplastics

• Polystyrene (PS): Obtained from benzene; resists impact. (Drawing tools, automobile interiors)
• Polyvinyl Chloride (PVC): Obtained from acetylene and hydrochloric acid; offers mechanical resistance and hardness. (Pipes, cabinets, windows)
• Polymethyl Methacrylate (PMMA): Transparent and impact-resistant. (Decorative items, goggles)
• Polycarbonate (PC): Derived from carbonic acid; features transparent gloss. (Police badges, CDs)
• Polyamide (PA): High strength, stiffness, and good toughness at high temperatures. (Toothbrushes, racket strings)

Thermosets

• Phenolic Resin (PF): A hard, dark, and fragile plastic obtained from phenol and formaldehyde. (Telephones, kitchen utensil handles)
• Polyester Resin (UP): Obtained from coal tar and styrene; resists temperatures up to 200°C. (Large pools, bumpers)
• Urea Resin (UF): Derived from urea and formaldehyde; colorless and insensitive to light. (Electric switches, plugs)
• Melamine Resin (MF): Produced from melamine and formaldehyde; odorless and tasteless. Used for food containers (plates, cups).
• Epoxy Resin (EP): Obtained from phenol and acetylene; provides good electrical insulation. (Sports equipment, aircraft wings)
• Polyurethane (PUR): Obtained from polyester and a benzene derivative. (Belts, rubber seals)

Elastomers

• Natural Rubber (CA): Milky juice obtained from the latex of certain tropical trees. (Mattresses, pillows, condoms)
• Neoprene (PCP): A polymer formed from chloroprene; provides fuel and thermal insulation. (Diving gear, fire protection)
• Silicone Rubber (SI): Resistant to external agents. (Prostheses, catheters, sealing)
• Synthetic Rubber (CS): Withstands heat. (Tires, gloves, boots)

Plastic Conformational Procedures

Press Molding

The mold is closed, the mass occupies the entire cavity, and it cools to acquire material strength before being removed.

Extrusion

Material falls into a worm screw that rotates inside a cylinder, where it is melted, homogenized, and pushed out the other end.

Injection Molding

Material is placed in a hopper and drops into an antechamber. A heated cylinder and piston push the material into the mold; it cools, and the piston returns to its set position.

Blow Molding

When the tube reaches the mold, air is introduced under pressure. It fits the chilled parts of the mold, adopting its form and becoming the desired hollow body.