4,4'-MDI HomopolymerCAS 25686-28-6
A specific oligomeric form of MDI used in industrial polyurethane systems — same sensitization profile as pure MDI.
Toxic Chemical Databases
Substance-specific listings — these flags are for 4,4'-MDI Homopolymer alone, not for the broader family.
Chemical Type
Aromatic Diisocyanate Oligomer
Chemical Description
The 4,4'-MDI homopolymer is the linear oligomer formed from repeated 4,4'-MDI units. It shows up in specialized polyurethane formulations including some adhesives and elastomers. Toxicologically it behaves essentially like pure 4,4'-MDI — a respiratory sensitizer with skin-sensitization potential, IARC Group 3 classification, and the same need to manage aerosol exposure during application.
Biological Activity
Severity scores specific to this substance, NOT the parent family average. Differences between siblings are real and meaningful.
Top Health Consequences
- Respiratory sensitization and occupational asthma
- Skin sensitization with direct contact
- Hypersensitivity pneumonitis with chronic exposure
Pathways of Exposure
- Inhalation of aerosolized A-side during application
- Skin contact with uncured polymer
- Re-aerosolization during demolition
Building Materials with 4,4'-MDI Homopolymer
Listed alphabetically — product categories where this specific substance appears.
Industrial Polyurethane Adhesives
Specialty Polyurethane Elastomers
Two-Part Coating Systems
How We Keep 4,4'-MDI Homopolymer Out of a House
Avoiding 4,4'-MDI Homopolymer is only half of it. The replacement has to work in a mold free, airtight, PHPP-modeled assembly as well — and finding materials that do both is most of what we do.
If you want a house specified this way from the start, or an existing house assessed for what is already in it, that is the work we do. Earth Bound Homes builds in Atherton, Palo Alto, Redwood City and across the San Francisco Bay Area.