A Full Service Custom Plastic Injection Molding Company
ISO 13485:2016

Polyurethane Injection Molding

Polyurethane thermoplastics are extremely versatile and can be formulated to provide wide-ranging characteristics. It exhibits excellent wear and abrasion resistance, and remains highly elastic and impact resistant, even at the hardest durometers or in extremely low temperatures.

Stack Plastics is a leading provider of injection molded polyurethane parts and components. We have over 20 years’ experience and extensive materials knowledge that enable us to produce high quality, high precision parts that match our customer’s exact design specifications. We maintain tight tolerances and can produce even the most complex parts with exceptional consistency and repeatability. 

Contact us for more information regarding our PU injection molding options for improved product wear and durability, or call us at 650-361-8600 and we will gladly assist you with your specific polyurethane injection molding questions. 

The Polyurethane Injection Molding Process 

Injection molding is a repetitive process with extremely fast cycle times that takes place in one specialized, automated injection molding machine. The PU injection molding process involves the following steps:

  1. Solid polyurethane pellets are directly fed into the machine’s injecting barrel.
  2. The barrel’s reciprocating screw pushes the polyurethane pellets towards the mold.
  3. The high shear action of the screw frictionally heats the pellets, fully melting them by the end of the barrel.
  4. When enough material has accumulated at the end of the barrel, the molten polyurethane is forced at high pressure and velocity into the mold in one shot.
  5. The material enters the mold through a series of gate channels.
  6. Once the material has solidified, the mold is opened, and the product is ejected using an array of pins, sleeves, and strippers.

PU Injection Molding Specifications 

Polyurethane offers excellent resilience—even the hardest polyurethanes can be formulated for rebound values up to 70%. These thermoplastic materials exhibit excellent dielectric properties, little to no water absorption, and are highly resistant to oil, grease, chemicals, and radiation. Polyurethanes can be formulated to withstand continuous use at temperatures as high as 248°F (120°C). 

At Stack Plastics, we can provide specialty copolymers that blend polyurethane and one or more other thermoplastic materials and combine their characteristics for improved performance, durability, etc. We carry polyurethane materials in durometers from 10-15 Shore A (softer than a pencil eraser) to 90 Shore D (hard as a golf ball). 

Advantages of Polyurethane Thermoplastic Injection Molding

PU injection molding produces parts and components that are versatile, modern and safe. They are used in numerous applications to create a wide range of products that are accessible, secure and environmentally friendly. Some of the direct benefits of utilizing injection molding polyurethane in the manufacturing of parts and components includes:

  • Light weight structure
  • Strong & durable
  • Impact resistant
  • Complex shape capabilities
  • Abrasion & wear resistant
  • Retains shape at high and low temperatures
  • Chemical resistant

Injection Molding Polyurethane Applications 

When utilized within injection molding processes, polyurethane thermoplastic material can be custom tailored to match specific project requirements. Some of the common applications that can be formed through the polyurethane injection molding process include: 

  • Car parts
  • Adhesives
  • Building components
  • Insulation
  • Composite panels
  • Sporting equipment

Differences Between Thermoplastic Polyurethane (TPU) & Rigid Thermoplastic Polyurethane (RTPU) 

Thermoplastic polyurethane (TPU) is an elastomer that is elastic and melt-processable. It can also be processed on extrusion as well as injection, blow and compression molding equipment. TPU provides a wide range of physical property combinations making it an extremely flexible material adaptable to dozens of uses. TPU maintains many excellent qualities including high elongation, increased tensile strength and outstanding elasticity.

Conversely, rigid thermoplastic polyurethane (RTPU) is an engineering thermoplastic that will mold to a tight dimensional tolerance without warping. Its chemical resistance is similar to a semi-crystalline material, providing excellent chemical resistance, good working flow and high impact strength.

Contact Stack Plastics for Polyurethane Injection Molding Services Today

Contact us for more information regarding our advanced PU injection molding processes, or request a quote for an in-depth price analysis today. Stack plastics is your premier full-service ISO Certified: 13485:2016 custom plastic injection molding company.