Epoxy resins are available in a variety of models with different properties, and their performance can be determined by characteristic specifications.
1. Epoxy equivalent (or epoxy value): Epoxy equivalent or epoxy value is the most important characteristic index of epoxy resin, which characterizes the content of epoxy groups in the resin molecule. Epoxy equivalent means the mass in grams of epoxy resin containing 1 mol of epoxy group, expressed as EEW. The epoxy value refers to the number of moles of epoxy groups in 100 g of epoxy resin.
2. Hydroxyl group: Hydroxy group means the number of moles of hydroxyl groups contained in 100 g of epoxy resin. The hydroxyl equivalent is the mass gram of the epoxy resin containing 1 mol of the hydroxyl group.
3. Esterification Equivalent: The esterification equivalent means the mass of the epoxy resin required to esterify 1 mol of the monocarboxylic acid. Both the hydroxyl group and the epoxy group of the epoxy resin can be esterified with a carboxylic acid. The esterification equivalent can represent the total content of hydroxyl groups and epoxy groups in the resin.
4. Softening point: The softening point of the epoxy resin can indicate the molecular weight of the resin, the relative molecular mass of the softening point, and the relative molecular mass of the softening point is small.
5. Chlorine content: refers to the number of moles of chlorine contained in the epoxy resin, including organic chlorine and inorganic chlorine. Inorganic chlorine mainly refers to chloride ions in the resin, and the presence of inorganic chlorine affects the electrical properties of the fixed resin. The content of organic chlorine in the resin indicates the content of the part of the chlorohydrin group in the molecule which has not been closed-loop, and its content should be reduced as much as possible, otherwise it will affect the curing of the resin and the properties of the cured product.
6. Viscosity: The viscosity of epoxy resin is one of the important indicators in the actual use of epoxy resin. At different temperatures, the viscosity of the epoxy resin is different, and its flow properties are different. Viscosity is usually measured by a cup viscometer, a rotary viscometer, a capillary viscometer, and a falling ball viscometer.