Paraffin Emulsions are mainly used for yarn finishing and textile finishing agents. Yarn finishing is the application of paraffin emulsions to finished threads. This treatment produces high gloss, deeper and more vivid colors, as well as higher elasticity and tensile strength. The application in finishing is mainly as an important component of textile finishing agents, with the aim of giving these textiles excellent soft hand, good smoothness and gloss, etc.
Molecular weight (degree of polymerization) Molecular weight of polyester resin
The degree of polymerization end coating anti-caking, crushability, melt viscosity, film leveling Figure 4-12 Polyester resin polymerization degree and glass as well as the physical and mechanical properties of the coating film and resistance to chemical media properties, etc. have a great influence on the relationship between the very chemical temperature (T,). In powder coatings, the degree of polymerization of polyester resin has a great influence on the glass (p-phenylene terephthalic acid, ethylene dispersion, neopentyl intoxicating system).
The relationship between vitrification temperature (Tg) is shown in Figure 4-12 for eaa emulsion sheets terephthalic acid, ethylene glycol, neopentyl glycol, and p-phenylene glycol.
For terephthalic acid, ethylene glycol, neopentyl glycol system, the degree of polymerization in 7 ~ 30, can produce a resin glass transition temperature greater than 50 ℃, good storage stability of powder coatings polyester resin.
In the synthesis of polyester resin, it is difficult to control the molecular weight distribution, which is determined by the catalyst or reaction conditions. According to Flory’s theory, the molecular weight distribution is determined by the reaction odds (p) and the number of functional groups (f) of the multifunctional components. Figure 4-13 shows the mass percentage distribution curve of the degree of polymerization, in which M, is the degree of polymerization x polymer mass percentage, in addition, the number average polymerization degree is only a function of p, so it is difficult to control the molecular weight arbitrarily, in the synthesis of polyester resin, how to accurately control the degree of polymerization is the key issue.
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