28 сентября, 2015 
Malyar The basic chemistry of emulsion-based acrylics is the same as their solution-based counterparts, in the sense that they are both combinations of hard and soft acrylic monomers, the ratios of which will dictate the final film properties. If a hard mar resistant coating with some alcohol and chemical resistance is desired, emulsions polymers with a Tg of 80°C will be required, unless the coating is crosslinked.
Other factors that will influence the properties of acrylic polymers are;
• The length of the ester side chain of the acrylic or methacrylic ester
• The presence of functionality in the ester side chain.
• The molecular weight.
High molecular weight imparts toughness to the polymer. Being discrete particle dispersions in water, emulsion polymers are better able to utilise this quality, since, unlike dispersion or solution types, they are not restricted by undesirable gains in viscosity brought about by increased molecular weight. However, being discrete particles the mechanisms of the initial stages of film formation are different to those of solvent based or neutralised water dispersed resins.
The resin system will generally be the major part of the finished material and will give the final coating most of its inherent physical and chemical properties. It may well be beneficial to mix resins in order to achieve the desired finished properties. However, care should be taken. Long term stability studies have shown that mixed emulsions can be problematic in storage.
Suppliers of emulsions and dispersions include:
Zeneca resins, Allied Colloids, Johnson Polymers, Vinamul and Rohm & Haas.
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