Applications
Bayhydrol® U 2757 can be used in combination with flexible polyurethane dispersions, e.g. Bayhydrol® UH 340/1, UH 650, UH 2305 and UH XP 2660 to formulate soft-touch coatings. In combination with polyacrylates, e.g. Bayhydrol® A 2058 highly chemical resistant comfort coatings can be formulated. Suitable polyisocyanate components are e.g. Bayhydur® 3100, 304, XP 2655 and also Desmodur® N 3600 and N 3900.
Form supplied
approx. 52 % in water / DMEA
Specification
| Property | Test Condition | Value | Unit | Standard |
|---|---|---|---|---|
| Viscosity | at 23 °C,(D = approx. 40 s^(-1) | 300 - 1,500 | mPa*s | DIN EN ISO 3219/A.3 |
| Non-volatile content | (1 g / 1 h / 125 °C) | 50,0 - 54,0 | % | DIN EN ISO 3251 |
| pH-value | 7,0 - 8,0 | DIN ISO 976 |
Typical Values
| Property | Test Condition | Value | Unit | Standard |
|---|---|---|---|---|
| Acid number | approx. 9 | mg KOH/g | DIN EN ISO 2114 | |
| Density | at 20 °C | approx. 1,07 | g/ml | DIN EN ISO 2811 |
| OH content (solid resin) | approx. 1,9 | % | ||
| Minimum film forming temperature (MFT) | < 0 | °C | DIN ISO 2115 |
Storage
- Storage in original sealed Covestro container. - Recommended storage temperature: 5 - 30 °C. - Protect from frost , heat and foreign material. General information: The product should be protected against frost.
Storage time
Covestro represents that, for a period of six months following the day of shipment as stated in the respective transport documents, the product will meet the specifications or values set forth in section "specifications or characteristic data" above, what ever is applicable, provided that the product is stored in full compliance with the storage conditions set forth in and referenced under section "storage" above and is otherwise handled appropriately.The lapse of the six months period does not necessarily mean that the product no longer meets specifications or the set values. However, prior to using said product, Covestro recommends to test such a product if it still meets the specifications or the set values. Covestro does not make any representation regarding the product after the lapse of the six months period and Covestro shall not be responsible or liable in any way for the product failing to meet specifications or the set values after the lapse of the six months period.
Processing
Sand and bead mills have proved suitable as grinding equipment. During grinding, the temperature of the mill base should not exceed 40 °C. The pH of coating systems based on Bayhydrol® U 2757 is between approx. 6.0 and 8.0 after formulation. The coatings can be applied using conventional spraying techniques. Depending on the application, drying conditions are 30 - 45 min at 80 °C.
After use, formulation and application equipment should be cleaned immediately or left to soak in water. Warm water, alkaline cleaning agents or alkaline isopropyl alcohol are suitable for cleaning.
