Knowde Enhanced TDS
Identification & Functionality
- Chemical Family
- Composite Materials Functions
- Technologies
- Product Families
Applications & Uses
- Markets
- Application Method
- Application Method
Do not overmix POLYCOR® 944 Series gel coats. Overmixing breaks down gel coat viscosity, increasing tendencies to sag, and causes styrene loss, which could contribute to porosity. Gel coats should be mixed once a day for 10 minutes. The gel coat should be mixing to the sides and bottom of the container with the least amount of turbulence possible. Air bubbling should not be used for mixing. It is not effective and only serves as a potential for water or oil contamination
Polynt Composites 944 gel coats are generally formulated for both airless and conventional spray applications. Neither brushing nor rolling is recommended. Refer to PB-16 (Application Guide) and PB-3 (Equipment Selection) bulletins for additional specific recommendations.
Polynt Composites recommends a gel coat delivery rate of no more than 2.5 pounds per minute with conventional air atomized equipment, and no more than 4 pounds per minute with airless equipment.
Batch mixing is recommended to achieve the best catalyst mix and cure because even with the equipment properly calibrated, potential problems can occur due to: poorly atomized catalyst; surging problems (gel coat or catalyst); poor tip alignment (catalyst to gel coat mix); contamination; and poor application procedures, which will quickly negate all benefits of calibration. The equipment (and application procedures) must be monitored on a routine basis to ensure proper application and cure of the gel coat. Ask about and adhere to all equipment manufacturers’ recommendations.
Avoid overspray settling on mold surfaces by beginning spray pattern closest to the vapor/air exhaust and progressing to the opposite mold end. Maintain recommended spray distances from the mold surface.
For best overall performance properties, a wet film thickness of 18 ± 2 mils is recommended as ideal. Films less than 12 mils may not cure properly, may be hard to patch, have more print-through, and are more susceptible to water blisters. Films above 24 mils may pre-release, trap porosity, or crack, and are more subject to weathering discoloration. If water blisters are of a great concern (boat hulls), 20 to 24 mils would perform better than a thinner film, but resistance to sag, porosity and cracking could suffer. If weathering (yellowing from sunlight, decks) is of great concern, then thinner films (12 to 16 mils) would perform better, but patchability and resistance to print-through and blistering could suffer.
Proper mold maintenance is important. Although Polynt Composites 944’s have excellent patching properties, minimal repair work is always desirable. Sanding and compounding can hasten the chalking and loss of gloss of all gel coats.
Properties
- Color
- Typical Properties
| Value | Units | Test Method / Conditions | |
| Sag Resistance at 77°F (Good) | 20 | mils | — |
| Flash Point at 77°F | 82-88 | °F | — |
| Weight per Gallon at 77°F (depending on color) | 9.0-11.0 | — | — |
| Viscosity, Brookfield RVF #4 Spindle at 4rpm at 77°F (White and Off-Whites) | 16,000-20,000 | cps | — |
| Viscosity, Brookfield RVF #4 Spindle at 4rpm at 77°F (Colors) | 11,000-16,000 | cps | — |
| Thixotropic Index (2/20) at 77°F | 5.5-7.5 | — | — |
| Volatile Organic Compounds at 77°F | 35-42 | % | — |
| Gel Time 2, 100 g mass, 77°F, 1.8% Arkema Luperox MEKP | 10-17 | minutes | — |
| Lay-up Time at 77°F | 45-60 | minutes | — |
| Hide (most formulations)at 77°F (Completed) | 10 | mils | — |
Technical Details & Test Data
- Cure
It is recommended that gel time be checked in the customer's plant because age, temperature, humidity and catalyst will produce varied gel times. All data referencing gel or cure refers specifically to Arkema Luperox® DDM-9 catalyst. United Initiators Norox® MEKP-9 and Norox® MEKP-9H, Akzo Nobel CADOX L-50a and CADOX D-50 are expected to yield similar performance. Arkema Luperox® DHD-9, Norox® MEKP-925 and Norox® MEKP-925H, and Pergan HP-90 may yield slightly shorter gel and cure times
The catalyst level should not exceed 3.0% or fall below 1.2% for proper cure. Recommended range is 1.2% to 3.0% with 1.8% at 77°F being ideal. Normally, the gel coat film is ready for lamination in 45 to 60 minutes. This time element is dependent on material temperature, room temperature, humidity, air movement, and catalyst concentration. Special fast cure versions are available but must be requested. These products offer lay-up times of 30 minutes or less depending on gel times. Fast cure products have shorter stability and should not be inventoried over 45 days.
These products (standard or fast-cure) should not be used when temperature conditions are below 60°F, as curing may be adversely affected.
Storage & Handling
- Handling and Storage
Uncatalyzed, standard cure gel coats have a shelf life of 120 days from date of manufacture when stored at 73°F or below, in a closed, factory sealed, opaque container, and out of direct sunlight. Fast cure gel coats (gel times less than 9.0 minutes) are stable for 60 days. The shelf life is cut in half for every 20°F over 73°F. Totes of product can have even shorter shelf life (66.0% of that for drums).