Plan a trial for your application
Weather-resistant topcoats
On the same substrate with identical formulation and cure, compare gloss retention and adhesion.
Two-component clearcoats
At equal resin solids and dry film thickness, measure working time and hardness development.
Purchase specifications and incoming inspection
Use these properties to compare grades within the product family. Example figures refer to the cited grade or source. Confirm the offered specification, packaging and lead time in the quotation. Covestro Desmodur N 3300 · HDI trimer ↗
| Property | Unit | Published or agreed specification | Test conditions and checks |
|---|---|---|---|
| NCO content | % by mass | Covestro Desmodur N 3300 published value 21.8 ± 0.3%, DIN EN ISO 11909 | Published third-party example. Agree measured acceptance limits for the grade to be purchased. |
| Viscosity | mPa·s | Agree for the grade and end use | State measurement temperature and the solvent used in the grade. |
| Free monomer | % by mass | Agree for the grade and end use | Verify the limits and analytical method for the actual grade. |
When approving a sample, record the grade, methods, limits and specification revision. On receipt, match the packing lot number to the lot-specific COA and record the measured values and release decision.
From samples to commercial delivery
Packaging and receiving
Protect from moisture and keep sealed. Confirm net weight, original closure and resealing after withdrawal.
Storage and handling
Review storage and transport against the offered grade’s SDS. Choose small packs or drums according to actual consumption.
Sample and order lead times
State processing equipment, trial batch size and monthly demand. Confirm same-grade samples, first-order MOQ, staged deliveries and arrival date.
Questions from the plant
Why is a skin forming around the drum opening?
Check moisture and time exposed after opening. Compare with an unopened same-lot sample.
Can hardeners of equal solids be exchanged at equal weight?
Calculate from NCO and base-paint hydroxyl equivalents, then prepare test panels with the complete formulation.
Report a delivery or batch issue
Include the order number, lot number from the package, label photos and inspection records for the affected lot. When retesting, check NCO content, Viscosity, Free monomer.
Request documents for your application
TDS · Technical data sheet
For grade selection and sample approval, specify the grade and revision required.
SDS · Safety data sheet
Specify the country or region of use and the required language.
COA · Certificate of analysis
Request a sample COA during supplier review. For incoming inspection, provide the actual lot number.