The drying characteristic of the resulting polymer is dependant on the oil length of the polymer (more oil, slower drying) and the amount of unsaturation that is present in the corresponding oil.
The correct HLB should be selected based on the emulsification temperature, the polymer charge density, and the polarity of the resin, which is determined by the acid number, oil length, and hydroxyl value.
Another goal of the study was to determine how versatile this particular modification was for different oil length alkyd systems.
Pigment flocculation is a common concern in coatings systems formulated with short or medium oil length
s Oil Type 45% 28/31 45% 28/31 AR AR Cloudpoint 120[degrees]C 150[degrees]C Test Oil 6/9 AFN 6/9 AFN Methanol 28ml/100g 20ml/100g 35ml/100g 35ml/100g Value Mw (GPC) 32000 29000 53000 200000 Acid 7 mg 7 mg 15 mg 20 mg Value KOH/g KOH/g KOH/g KOH/g Oil Length
73% 66% OH-Value 15 mg 16 mg 46 mg 44 mg KOH/g KOH/g KOH/g KOH/g SETALIN[R] EPD 7970 MK 179 Viscosity 7 Pa.
Traditional methods to increase solids such as reactive diluents (3) or increasing the oil length decrease Mn, which has a detrimental effect on dry times, final coating hardness, and humidity resistance.
Additional reductions in resin viscosities were achieved by increasing the oil length to 65 and 70% but this also resulted in a decrease in Mn to below 3,500.
The effect of oil length and type of SAA used on hardness development was also investigated.