Vinyl ester mortar

Polyester and Vinyl Ester Mortars These two mortars, of which there are many types, are suitable for a pH range of about 0-11 and a continuous service temperature of 225°-230°F. The two related resins, which complement the epoxy resins, resist dilute and concentrated acids and weak alkalies. Their resistance to acid bleaches such as chlorine dioxide and to oxidizing acids such as nitric and chromic is superior to that of other resinous mortars, and they are excellent in acetic acid and related esters. However, polyester and vinyl ester mortars are the poorest resin mortars in other organic chemical exposures including solvents in general. Such mortars are widely used in paper mills and are suitable with acid brick or ceramic tile in the lower temperature zones of mildly acidic utility FGD systems. 

Occasional repointing of the mortar joints is normally the only maintenance required. In the dilution zone, where attack of the Portland cement mortar may occur, repointing with a polyester or vinyl ester mortar will usually solve the problem. If voids are detected in the wall, these can be filled by pumping a port-land cement mix or a catalyzed resin into the wall by the technique described for filling voids in a digester lining. The service and maintenance history of these vessels has generally been excellent. 

The chlorination tower lining is tile set in a polyester or vinyl ester mortar with a Portland cement grout backing. The hypochlorite and peroxide units do not need the resistance of the resin mortar, therefore, Portland cement mortar can be used. Caustic extraction towers are occasionally lined with tile set in Portland cement mortar even though the alkaline operating conditions may soften the tile. To minimize the softening effect, the tile should have an extremely tight, well fired body. 

Table 7.13 Comparative Resistanoe of Vinyl Ester Mortars ...

These resins have many of the same properties as the epoxy, acrylic, and Bisphenol A fumurate resins. The vinyl ester resins have replaced polyester resins in mortars for bleach towers in the pulp and paper industry. The major advantage of these resin systems is their resistance to most oxidizing mediums and high concentrations of sulfuric acid, sodium hydroxide, and many solvents. Comparative resistances of the two types of vinyl ester mortars are shown in Table 7.13. 

The selection of the resin is made in the same manner as the selection of the brick mortar, covered elsewhere in this volume, with the exception that the binder of the membrane must be a resin-not a silicate or a sulfur-and the order of choice is, first, the lowest possible shrinkage furan, then a phenolic and, finally, only if one of these two is unable to handle the chemical exposure, a vinyl ester or a polyester. 

The mortar may be applied to properly prepared concrete or steel substrates by usual acid-resistant bricklaying methods. An epoxy, urethane asphalt, bi-tumastic, polyester or vinyl ester membrane is required behind the block to ensure corrosion protection of the substrate. Because the mortar joints are rigid, a system of expansion/contraction joints, usually filled with ceramic paper, must be designed to prevent cracks. 

Mortars used in the past have primarily been composed of Portland cement, silicates, and litharge and glycerine. Except for Portland cement, these traditional materials have generally been replaced by resin mortars utilizing epoxy, polyester, vinyl ester and furan resins. 

The normal lining construction consists of a membrane on the steel shell and one layer of acid brick in a resin mortar. The membrane materials used have been a silica filled latex rubber or, more recently, a silica filled urethane. Either of these membranes is installed by troweling it onto the steel shell. The mortars used have been polyester or vinyl ester based and are used in the back joints, bed joints, and side joints. That is, the brick are completely surrounded by the mortar, except, of course, for the face. The equipment in which this type of construction is used includes the chlorine dioxide storage tank, the chlorine dioxide generator spent acid tank, and the chlorine dioxide bleach tower. 

Chemester. [Atlas Minerals Chem] Vinyl ester floor topping and mortar. 

Peimchem Mortar. [AtochemN.Am.] Two-component, silica-filled chmnical-resistant vinyl ester resin-based mortar mortar for construction in pulp/pa-per, chemical process, food and b er-age plant industries. 

Large towers have carbon steel shells. Brick linings, a standard in the past, are still widely used. These usually comprise two courses of acid-resistant brick held in place over a suitable protective membrane. Vinyl ester resins are suitable for the membrane and the mortar that holds the assembly together. Many systems use unlined carbon steel in the last (driest) stage. Other linings have begun to find some application these include... 

Vinyl Ester and Vinyl Ester Novolac Mortars... 

The same vinyl ester formulations are used for mortars and grouts as are used for monolithic surfacings. They have a limited shelf life and should be stored below 60 F (7°C). Any of the formulations provide suitable protection from normal atmospheric corrosion (see Table 10.3). 

Property at 75°F Test no. Polyester Filament wound epoxy Filament wound vinyl ester Filament wound reinforced plastics mortar... 

In the 1960s, styrene-butadiene rubber-, polyacrylic ester-,l and poly(vinylidene chloride-vinyl chloride)- modified mortars and concretes became increasingly used in practical applications. Since the 1960s, the practical research and development of polymer-modified mortar and concrete have been considerably advanced in various countries, particularly U.S.A., U.S.S.R., West Germany, Japan, and U.K. Consequently, a considerable number of publications including patents, books, papers, and reports have appeared. Of these, the main and important studies are as follows ... 

Research on the effect of monomer ratio in copolymer dispersions [e.g., SBR latex, poly (ethylene-vinyl acetate) (EVA) and poly (styrene-acrylic ester) (SAE) emulsions] on the strength of polymer-modified mortar using copolymer dispersions [21-23]... 

---