VFI®-4478 85 D Prototyping Polyurethane Plastic

VFI®-4478 85 D Prototyping Polyurethane Plastic

VFI-4478 85 D Prototyping Polyurethane Plastic is a premium urethane plastic for use in a reaction injection molding (RIM) system. It is capable of being backfilled with a urethane foam to create a light and durable part. VFI-4478 is used to make high-end, fire-retardant plastic housings and parts for a variety of industries, including medical, automotive, and aerospace. 

VFI-4478 85 D Prototyping Polyurethane Plastic from VFI is a premium, fire-retardant urethane for use in RIM systems to create plastic housings and parts.

Features & Benefits

  • Works in reaction injection molding applications
  • Capable of passing the UL 94-V0 test
  • Able to be post-processed with a CNC or general milling machine
  • Will flash to white and is paintable
  • 1:1 mix ratio by weight

Instructions for Use:  

Mold Preparation  

Release agents are recommended for all molding applications to extend the life of the mold. When using prototyping urethane molds, release agents are a requirement. We do not recommend using a heated mold or any mold over 115°F with this product.  

Casting Process 

The B side (Poly) of VFI-4478 85 D Prototyping Polyurethane Plastic must be premixed once daily before use without introducing extra moisture or air into the material. Prepare a container with a recommended headspace of at least 2/3 for vacuum degassing. Pour the measured A side material into the container, followed by the measured B side material. Using a hand or power mixer, mix the material until uniform. All mixing, vacuum degassing, and pouring must be done before the end of the pot life.  

To fully cure the part at room temperature, the material cannot be poured or RIM processed less than a quarter inch thick. If a thinner pour is needed, the mold and molding temperature must be elevated to 115°F.  

Once the material has cured at room temperature for 16 hours, heat curing at 150°F for 24 hours will allow it to achieve full physical properties. The material’s physical properties will be delayed until after seven days and may never fully develop without post-curing in an oven.  


*Always read the safety data sheet before working with chemicals  

Use chemicals only as directed and for their intended purpose. Do not dispose of chemicals down the drain. Most chemicals must be disposed of as hazardous waste.   

PPE to avoid unnecessary exposure:  

  • Eye protection – wear approved safety glasses and any additional eye protection as necessary 
  • Hand protection – wear chemically resistant protective gloves (nitrile, butyl, or neoprene) 
  • Skin and body protection – wear suitable protective clothing 
  • Respiratory protection – in case of insufficient ventilation, wear suitable respiratory equipment. Respirator selection must be based on known or anticipated exposure levels, the hazards of the product, and the safe working limits of the selected respirator 

Product Limitations  

This product contains isocyanate, which can be irritating when in contact with the skin or toxic if inhaled.  

  • Incompatible materials – A side: water, alcohols, amines, bases, and acids. B side: oxidizers 
  • Conditions to avoid – heat and incompatible materials  
  • Chemical stability – stable under normal storage conditions 
  • Reactivity & hazardous reactions – no dangerous reaction known under normal use  
  • Hazardous decomposition products – A side: carbon monoxide, carbon dioxide, nitrogen oxides, hydrocarbons, and HCN. B side: may include but is not limited to, oxides of carbon 

Potential Health Hazards  

  • May cause respiratory tract irritation. A side material may also cause allergy and asthma symptoms or breathing difficulties. 
  • May cause stomach distress, nausea, or vomiting if swallowed.  
  • May cause skin irritation or sensitization: redness, edema, drying, defatting, or cracking. Repeated exposure to the B side material can result in absorption through the skin, causing a significant health hazard.  
  • Causes serious eye irritation: discomfort, pain, excess blinking and tear production, marked redness, and swelling of the conjunctiva.  

*If you are experiencing any of these symptoms, seek medical advice or attention. Call a poison control center or doctor if swallowed. 

Application Methods:

  • Inject Inject

Available Packaging:

  • Tote
  • Drum
  • 5 Gallon