Paper sizing with resin acids

Haxz-karboUdsung, /. (Paper) solution of rosin in carbolic acid, -keraselfe, /. rosin curd soap, rosin soap, -kiefer,/. pitch pine, -kitt, m. resinous cement, -kocher, m. (Paper) rosin boiler, -kohle, /. bituminous coal, -kdrper, m. resin(ous) substance, -lack, m. resin lake resin varnish, -leim, m. (Paper) rosin size, -leimung, /. (Paper) sizing with rosin, -leimverseifung, /. rosin-size cutting. ... 

Traditionally papermaking is made at acid pH of about 4.5. Because of this the sizing of paper is carried out with resin acid salts in the presence of alum. Under these conditions, the resin acid anions complex with the aluminium cations and the complex formed is attracted to and deposited on the fibre surface. The purpose of sizing is to render the paper more resistant to water-based printer s ink. Today there is much interest in so-called alkaline sizing at about pH 7, which is preferred for specialist long-life papers. Here sizes such as alkyl ketene dimer replace alum. Alkaline papermaking has the further advantage that fillers such as calcium carbonate can be employed. 

Alkenylsuccinic anhydrides made from several linear alpha olefins are used in paper sizing, detergents, and other uses. Sulfosuccinic acid esters serve as surface active agents. Alkyd resins (qv) are used as surface coatings. Chlorendric anhydride [115-27-5] is used as a flame resistant component (see Flame retardants). Tetrahydrophthalic acid [88-98-2] and hexahydrophthalic anhydride [85-42-7] have specialty resin appHcations. Gas barrier films made by grafting maleic anhydride to polypropylene [25085-53-4] film are used in food packaging (qv). Poly(maleic anhydride) [24937-72-2] is used as a scale preventer and corrosion inhibitor (see Corrosion and corrosion control). Maleic anhydride forms copolymers with ethylene glycol methyl vinyl ethers which are partially esterified for biomedical and pharmaceutical uses (189) (see Pharmaceuticals). 

Tall oil is made up mostly of resin acids with around 10% of neutral components. These resin acids are isomers or structurally close relatives of abietic acid (Figure 2.9) and are used as antislip agents, as a chemical feedstock and as paper-sizing agents (see Chapter 7). 

Rosin exploitation, a part of the so-called Naval Stores Industry, is at least as old as the construction of wooden naval vessels. In recent years, rosin components have attracted a renewed attention, notably as sources of monomers for polymers synthesis. The purpose of the present chapter is to provide a general overview of the major sources and composition of rosin. It deals therefore with essential features such as the structure and chemical reactivity of its most important components, viz. the resin acids, and the synthesis of a variety of their derivatives. This chemical approach is then followed hy a detailed discussion of the relevant applications, the resin acids and their derivatives, namely in polymer synthesis and processing, paper sizing, emulsion polymerization, adhesive tack and printing inks, among others. 

Na, Mg, Ca, Zn, A1 and ammonium resin acid salts are produced industrially [5], albeit their relative importance has been shifting with time because of changes in their relevant applications. Na, K and ammonium salts are partially water soluble and were used as soaps in the past. Presently, resin acids sodium salts are mainly used as intermediates in paper sizing. 

The discovery in 1807 that water resistance in paper could be achieved by precipitating partially saponified rosin with alum on pulp led to a market that has been the major use of rosin for many years. In addition to the simple aqueous dispersion of sodium resinate, called paste size, rosin sizes in emulsion and dry form are also used. The composition of the rosin, the amount of neutrals and oxidized components as well as the resin acid composion, affects the efficacy and physical properties of a size. The efficiency of rosin sizes is improved by fortifica-... 

The production of resin acids and terpenes from pine stump extraction and the distillation of tapped gum (oleoresin), sulfate turpentine, and kraft tall oil are equal to or greater than the existing markets, most of which continue to show marginal declines. The net results are depressed pricing and a somewhat cloudy future, particularly for tall oil rosin, which is faced with changing technology in one of its major end-uses - paper-sizing additives. 

---