Part Size
Large parts need stable processing and good flow
Reaction Injection Molding (RIM) Materials: Polyurethane Foam Systems
Rimnetics works with polyurethane RIM materials that are engineered for strength, surface finish, dimensional stability, and part consolidation.
Understanding RIM Materials
Reaction injection molding materials are liquid polyurethane systems that react inside a mold instead of being melted from pellets like thermoplastics. That difference matters because it gives engineers more control over part density, stiffness, weight, surface finish, and wall thickness.
For Rimnetics, the materials conversation starts with fit. The best PUR system is not the one with the biggest spec sheet. It is the one that matches the part size, performance target, cycle time, and production volume.
Choosing the Right Material for Your Part
Material selection in RIM should start with the part’s function. A rigid polyurethane foam may be the right choice for a structural enclosure. A compact foam may be better when you need a dense, clean-looking part with strong surface detail. An elastomeric system may be better when impact resistance and flexibility matter more than rigidity.
Here’s what drives the decision
Load Requirements
Structural applications usually need higher stiffness
Surface Requirements
Cosmetic or visible parts need better finish and detail
Weight Limits
Higher-density compact systems add rigidity
Impact Exposure
Parts subject to repeated impact need a flexible material that absorbs impact
Tooling Investment
The material must justify purge, setup, and cleaning costs
Rimnetics also considers whether a part can be consolidated. In many applications, the smartest material choice is the one that lets you turn a 10-piece or 15-piece assembly into two or three molded components.
RIM Materials We Process
Rimnetics primarily works with PUR systems and commonly processes the following materials:
| Material | Details | Typical Fit |
|---|---|---|
| Covestro Baydur 726, Structural Foam | High-density polyurethane structural foam used for rigid, load-bearing parts with strong surface finish and large-part capability | Structural enclosures, equipment housings, industrial covers |
| Covestro Prism CM-200, Compact Foam | A compact polyurethane foam suited to dense molded parts where rigidity, detail, and dimensional stability matter | Technical housings, covers, and precision-fit components |
| Covestro Bayflex Family of PURs | Elastomeric polyurethane systems designed for impact resistance, toughness, and flexibility | Protective components, impact-prone parts, and applications needing deflection |
| Other Qualified PUR Systems | Rimnetics can run additional systems when the quantity justifies purge and cleaning of the wet system | Program-specific applications that need a custom or different material |
Reaction Injection Molding Materials for Every Industry & Application
Medical Devices
Laboratory Equipment
Robotics
Electronics
Industrial Equipment
Why Partner with Rimnetics?
The wrong material adds cost in three places at once: tooling, assembly, and downstream performance. The right one reduces all three. That is where Rimnetics creates the most value.
- ✓Deep experience with rigid polyurethane parts for medical and industrial applications
- ✓Hands-on knowledge of structural foam, compact foam, and elastomeric PUR behavior
- ✓Part consolidation expertise that reduces tooling and assembly costs
- ✓Material guidance across stiffness, impact resistance, surface quality, etc.
- ✓Ability to run additional PUR systems when program volume supports it
FAQ
RIM Materials FAQs
What is polyurethane foam?+
Polyurethane foam is a thermosetting polymer created from reactive liquid components. Depending on how it is formulated, it can be rigid, semi-rigid, or elastomeric. In RIM applications, it is used to produce structural parts, enclosures, housings, and other molded components that need performance beyond a basic plastic part.
What is polyurethane foam used for?+
Polyurethane foam is used for structural enclosures, equipment housings, insulation, protective covers, and parts that need a balance of strength and weight reduction. In manufacturing, it is valued because it can be molded into large, complex shapes and can also support part consolidation.
What is the difference between structural foam and rigid polyurethane foam?+
Structural foam is typically used to describe a polyurethane system that combines a strong outer skin with a lower-density core. Rigid polyurethane foam is the broader category of stiff PUR materials. In practice, both are chosen when a part needs rigidity, lightweight performance, and good surface quality.
What are polyurethane properties that matter most in RIM?+
The most important polyurethane properties are stiffness, impact resistance, dimensional stability, surface finish, chemical resistance, and weight. The right mix depends on the application. For example, a structural enclosure usually prioritizes stiffness and finish, while an impact-prone component may need more flexibility.
Can Rimnetics run materials outside the Baydur, Prism, and Bayflex families?+
Yes, Rimnetics can run other PUR systems when the production quantity justifies the purge and cleaning required for the wet system. That said, the material must still be a good fit for the part, process, and volume before it makes sense.
Can Rimnetics help with material selection?+
Yes. Rimnetics helps evaluate part size, load, surface, weight, and impact requirements to identify the best PUR system for the application. The goal is to match material performance to the part, not to force a one-size-fits-all solution.
No commitment required
Need Help Choosing RIM Molding Materials?
If you are evaluating RIM molding materials, Rimnetics can help identify the right polyurethane system before tooling decisions are locked in. Reach out to us today to speak with a RIM specialist.