What is Injection Molding with Polystyrene?

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ICOMold has been producing custom polystyrene and other thermoplastic injection molded parts for many years. Our team of experts will work with you to find the best material for your unique project. The custom plastic injection mold created for your product will last over 100,000 cycles, increasing your efficiency and uniformity while passing on cost-savings to the customer.  

Polystyrene (PS) is a transparent thermoplastic most often used to create single-use products. It is odorless and non-toxicPolystyrene is available in either solid or foamed. As a solid, it is used to make plastic cutlery, electronics, toys and auto parts. As a foam (Styrofoam), it can be extruded to make packing peanuts, disposable drinking cups and more. Injection molding polystyrene has many advantages and applications. 

Advantages of Injection Molding Polystyrene 

Polystyrene is a popular material for injection molding because it is cost-effective and versatile. Some of these primary benefits of using polystyrene for injection molding projects include:

  • Cost-effective
  • Recyclable 
  • Durable 
  • Lightweight 
  • Can be used for insulation 
  • Moisture resistant 
  • Bacteria resistant 
  • Transparent

Injection Molding Polystyrene Specifications 

Polystyrene is a homopolymer made only of a combination of monomer styrene available as foam or solid. It is clear, hard and brittle. As a thermoplastic, it will become liquid at a melting point of 410-480F. Once polystyrene has been liquified, it can be cooled into a solid, then reheated again without degradation. Its ability to liquefy instead of burn is what makes it a good material for injection molding. It is not biodegradable. Properties of polystyrene: 

  • Melting Point: 410-480F 
  • Tensile Strength~7700 psi 
  • Injection Molding Temperature: 100-150F 
  • Impact Strength ~0.8 ft-lb/in notched Izod    
  • Hardness LevelR75 
  • Flexural Strength~12000 psi 
  • Shrink Rate: 0.3-0.7% 

Polystyrene is also available as a thermoset plastic. Thermoset plastics can only be heated once as attempting to heat them a second time would cause the material to burn. Polystyrene in thermoset form is not recyclable. 

Injection Molding Polystyrene Process 

To begin the injection molding process, the polystyrene is heated into a liquid form. It is then added to a two-sided mold to create the desired shape. Once the item has cooled, it is released into a bin and then moved into postprocessing for finishing touches. The advantage of using injection molding for your polystyrene part is that once the tool has been made, it can be used over and over again, producing a large volume of high-quality polystyrene products. 

Applications of Injection Molding Polystyrene 

Polystyrene is popular in both foam or plastic form. Polystyrene foam is easy to cut, paint, sand, glue and is widely available. Polystyrene in plastic form is most commonly used for disposable items, such as food packagingSome common uses of polystyrene in injection molding include: 

  • Plastic tableware 
  • CD jewel cases 
  • Food containers 
  • Plastic model kits 
  • “To-go” boxes 
  • Packing material 
  • Lab equipment 
  • Water bottles 
  • Medical equipment 
  • Cups 
  • Insulation 
  • License plate frames 

Get a Quote on Injection Molding Polystyrene Today 

ICOMold can work with you on the design and production of your polystyrene part. Get an instant quote today.  

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