To understand the capabilities of the novel alkyd platform this paper presents performance data from different applications comparing the novel alkyd against a similar oil length conventional alkyd.
In the higher oil length formulas the novel alkyd platform is more constrained by these higher oil/ fatty acid levels.
The viscosity can be reduced by decreasing the molecular weight of the alkyd resin by changing the dibasic acid/polyol ratio or by increasing the oil length. Although these changes result in VOC reduction, high-solids alkyds typically have longer dry times and reduced chemical/corrosion resistance properties compared to those from traditional SB alkyds.
In general, the shorter the oil length of the alkyd resin, the higher the temperature required; therefore, this technique is typically limited to medium- and long-oil alkyds.
The optimal composition of the MO alkyd resin was determined through the completion of DoEs varying the oil length, degree of branching, effects of molecular structure, and acid content (Table 4).
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.
Pigment flocculation is a common concern in coatings systems formulated with short or medium oil length
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.