Лако-красочные материалы — производство

White pigments are conveniently classified as either hiding or non-hiding types, depending on their ability to provide opacity. By far the most important white opaque pigment is titanium dioxide (TiO2, C. I. Pigment White 6). It finds widespread use in paints, plastics, printing inks, rubber, paper, synthetic fibres, ceramics and cosmetics. It owes its dominant […]

Natural inorganic pigments, derived mainly from mineral sources, have been used as colorants since prehistoric times and a few, notably iron oxides, remain of some significance today. The origin of the synthetic inorganic pigment industry may be traced to the rudimentary products produced by the ancient Egyptians, pre-dating the synthetic organic colorant industry by several […]

The distinction between pigments and dyes, which is based on the dif­ferences in their solubility characteristics, has been discussed in detail in Chapter 2. A pigment is a finely divided solid colouring material, which is essentially insoluble in its application medium. Pigments are used mostly in the coloration of paints, printing inks, and plastics although […]

The principles of the synthesis of the important chemical classes of dyes from which reactive dyes may be prepared have been discussed in Chap­ters 3 -6 of this book. This section deals specifically with those aspects of the synthetic sequences which are used to introduce the fibre-reactive group. The starting material for the synthesis of […]

A selection of representative chemical structures from the vast range of reactive dyes now available commercially is given in Figure 8.5. Reactive dyes may be prepared in principle from any of the chemical classes of colorant by attaching a fibre-reactive group to an appropriate molecule. In common with most application classes of textile dyes and […]

There is no doubt that the major weakness of the reactive dyeing process is the hydrolysis reaction and the consequent need for a wash-off process. The extent to which dye hydrolysis takes place in competition with dye-fibre reaction varies quite markedly within the range 10-40% de­pending upon the system in question. A considerable amount of […]

A characteristic feature of the chemistry of aromatic ring systems is their tendency to undergo substitution reactions in which the aromatic charac­ter of the ring is retained. Since most aromatic systems are electron-rich in nature, by virtue of the system of re-electrons, the most frequently encoun­tered reactions of aromatic compounds are electrophilic substitution reactions. Nucleophilic […]

Cotton fibres are based on cellulose, a polysaccharide, whose structure is given in Figure 7.4. Most reactive dyes for cotton utilise the ability of the many hydroxy (OH) groups present in the cellulose molecule to act as nucleophiles. The dyes are commonly induced to react with the cellulose in aqueous alkali under which conditions deprotonation […]

It is probable that history will judge the development of reactive dyes to have been the most significant innovation in textile dyeing technology of the 20th century. As a consequence of their particular importance, and because they make use of some interesting organic chemistry, this chapter is devoted entirely to a consideration of the chemical […]

The three most important types of synthetic fibres used commonly as textiles are polyester, polyamides (nylon) and acrylic fibres. Polyester and the semi-synthetic fibre cellulose acetate are dyed almost exclusively with the use of disperse dyes. Polyamide fibres may be coloured using either acid dyes, the principles of which have been discussed in the section […]