Лако-красочные материалы — производство

Another important class of modified epoxy resins, known as epoxy acrylates, are reaction products of a low MW epoxy resin and acry­lic acid or methacrylic acid, which are used in radiation curable systems. The acrylate functionality is ~2, but higher functionality variants can also be prepared by using epoxy phenol novolac in place of BPA […]

A majority of the epoxy esters used in the coating industry are syn­thesized by reacting an epoxy resin with fatty acids from drying, semidrying or non-drying oils based on the end-use requirements for their properties. For epoxy ester resins suitable for air-drying (autoxidative curing), drying or semidrying oil fatty acids are used, while for stoving […]

Epoxy resins are often modified through their reactive oxirane groups as well as hydroxyl groups to design molecules meeting special requirements. Below are some important modifications.

This class of epoxide resins is completely different than the resins discussed so far. Internal epoxy groups (Figure 2.43) have very different reactivity compared to glycidyl epoxy groups. These epoxy resins are typically prepared by epoxidation of carbon double bonds (olefin type) using peracids or hydrogen peroxide. Epoxidized vege­table oils (mainly soybean oil and linseed […]

Reactive diluents are low viscosity mono — or difunctional epoxies based on aliphatic alcohols, diols, alkylated phenols or carboxylic acid that are used to reduce the viscosity of standard epoxy resins and react with curatives during the curing process (Figure 2.42). They tend to reduce chemical resistance, heat resistance and hard­ness of the coatings. The […]

Poor light fastness (exterior durability) of BPA type epoxy resins, due to the presence of aromatic ether linkages, limits their outdoor applications. Epoxy resins with improved weathering performance can be obtained by using aliphatic epoxy resins. One of the impor­tant epoxy resins in this class is the glycidyl ether of hydrogenated bisphenol A. These resins […]

Most of the BPA-based epoxy resins are quite rigid and are based on petrochemicals. A quite different type of flexible epoxy resin is based on cardanol, derived from cashew nut shell liquid. Mono-, di — and multifunctional derivatives are possible. Mono — and difunc­tional low viscosity derivatives are used as modifiers and diluents, while complex […]

Brominated BPA epoxy resins are analogues to BPA epoxy resins that are derived from tetrabromobisphenol A (Figure 2.40). These resins are supplied both as liquid and solid grades and are mainly used for fire retardant applications. They are copolymerized with BPA to derive various grades with varying bromine content (up to 48 %).

Being a glycidyl ether of a novolac type phenol formaldehyde resin, epoxy phenol novolac resins (Figure 2.39 (a)) are the polymeric mul­tifunctional counterpart of bisphenol F resin. They are supplied as highly viscous through semisolid to solid resins. They are generally prepared by reacting epichlorohydrin with novolac type phenol formaldehyde resins. Figure 2.39: Some multifunctional […]

Another aromatic ether type of commercial epoxy resins, analogous to BPA epoxy resins, is based on bisphenol F. Such epoxy resins are known as bisphenol F epoxy resins (Figure 2.38). Compared to BPA, bisphenol F epoxy resins have lower visco­sity, and their cross-linked films have higher Tg and heat distortion temperatures along with better solvent […]