Freeze-thaw agents depress the freezing point of the water by increasing the resistance to freezing. Since the external phase of the system is primarily water, freezing temperatures turn the water into ice and solidification occurs. On thawing, the various volatile components reach maximum solubility at different times. The protective colloid will re-dissolve in the melting ice at different rates. If the cold flow occurs to the polymer particles before the protective agents become effective again, the system will remain in a flocculated or coagulated condition. The effective means of promoting freeze-thaw resistance also decreases the coating’s over-all water resistance. Depressing the freezing point of the water does increase the resistance to freezing by the discriminate use of ethylene glycol, propylene glycol, glycol, ethers, or prolyoxyethylated non-ionic.
Modifiers for pH stability reduce the drift downward from an optimum pH. Lowering the pH from the degree of alkalinity to more acidic will cause a marked loss of both surfactant solubility and stabilizing action in the system.
A property that has a large bearing on the product performance in surface coatings is the dispersion polymer particle size. The particle size is a function of the number of particles initiated since the more particles that are formed the smaller will be the final particle size. Particle size has at least some relationship to all of the following coating properties: gloss, flow, leveling, pigment binding, hiding power, coalescence, viscosity, mechanical and freeze-thaw stability, porosity, and all secondary properties that depend on these characteristics. Product performance has combined advantages of the technology of urethane chemistry and acrylic chemistry.
Urethane chemistry offers the following:
• Abrasion resistance
• Polymer film flexibility
Acrylic chemistry offers the following:
• Film hardness
• High gloss @ 60 degrees/Excellent clarity @ 20 degrees
• Gloss retention
• Ultraviolet resistance
• Stability to light and heat
• Good exterior durability
• Good pigment binding
• Small particle size
• Excellent adhesion
Waterborne KolorBond offers excellent adhesion, after the cure period, to various plastic substrates. Typical of waterborne systems, the cured dry film is dependent upon proper air movement and ventilation. The fully developed cure can take up to seven days at ambient room temperature. Forced drying at elevated temperatures reduces the curing period. Optional infrared curing reduces the curing period by 50%.
BALANCED CONTRASTING REQUIREMENTS:
|Package Stability (Storage)||vs.||Good Coalescence|
|Freeze-thaw Resistance||vs.||Poor Coalescence|
|Good Flow||vs.||Good Sag Resistance|
|Poor Substrate Wetting||vs.||Good Leveling and Low Foaming
(High Surface Tension)
|Good Flexibility||vs.||Good Hardness|