Polymeric MDI is supplied in different grades for polyurethane manufacturing. A grade name identifies a particular supplier product; it is not a universal specification shared by all manufacturers. Compare the current technical documents and intended application before selecting a grade or assessing a potential alternative.
What Is Polymeric MDI?
Polymeric MDI, abbreviated pMDI or PMDI, is a mixture containing MDI isomers and higher-functionality species. It is widely used in rigid polyurethane foam, with appropriate grades also used in PIR foam and other applications. It is a distinct product family from monomeric MDI.
A pure or monomeric MDI product should not be placed in a polymeric MDI grade list simply because it shares the MDI name. Likewise, a modified MDI or prepolymer should be identified using the manufacturer product description.
How Do Polymeric MDI Grades Differ?
Relevant differences can include composition, NCO content, viscosity and other product specifications. The manufacturer may also identify particular applications or processing characteristics. Use the current TDS for the exact grade; avoid inferring a product specification from part of its grade code.
| Selection Topic | What to Compare |
|---|---|
| Product identity | Manufacturer, complete grade designation and product family. |
| NCO content | The stated specification or typical value, units and test method. |
| Viscosity | The stated value or range together with its test temperature, units and method. |
| Application | The manufacturer recommended uses and the requirements of your complete formulation. |
| Quality documentation | Current TDS, SDS and batch documentation required by the purchase specification. |
Are Similar Grades Automatically Interchangeable?
No. Similar specification values or a shared application description do not establish full equivalence. Finished-product behavior also depends on the other formulation components and production process. A proposed grade change should be assessed against the technical requirements and approval procedure for your system.
When asking for a comparison, provide the current manufacturer and grade, the application, the process and the properties or acceptance criteria that must be retained. This supports a documented assessment rather than an unsupported replacement claim.
How to Choose a Grade for Rigid Foam Insulation
Identify the insulation application and whether the system is rigid PU or PIR. Explain the production method and relevant finished-product requirements. Then compare the grade documentation with those requirements and request technical review where needed. Our rigid foam insulation guide lists useful enquiry questions.
Explore the Listed Products
Browse our polymeric MDI product group for the current catalog selection. The Wannate PM-200 product page provides information on one listed polymeric MDI grade. Review its own documentation rather than treating the page as a specification for every pMDI product.
For other MDI families, visit the MDI catalog or read about MDI types and applications.