Resin cements

Resin additives Resin cements Resin component Resin cure systems Resin curing agents Resin formation Resin-in-pulp Resinoid Resinols Resins... 

In North America, a special, high conductivity, low permeability, "hot-pressed" carbon brick is utilized almost exclusively for hearth walls. Because of their relatively small size and special, heat setting resin cement, and because the brick is installed tightly against the cooled jacket or stave, differential thermal expansion can be accommodated without refractory cracking and effective cooling can be maintained. Additionally, the wall thickness is generally smaller than 1 m, which promotes the easy formation of a protective skull of frozen materials on its hot face. Thus hearth wall problems and breakouts because of carbon wall refractory failure are virtually nonexistent. 

Resin cements have excellent aesthetic quahties and are essentially insoluble in mouth fluids. Compressive strength is low, but can be increased by the addition of fillers. They have no inherent adhesion to the tooth. Retention is dependent on mechanical locking when the cement flows into irregularities on the surfaces of the substances being cemented. 

Resin cement materials are provided as a two-part powder—Hquid product. The powder consists largely of poly(methyl methacrylate) to which various fillers (qv) maybe added. These include calcium carbonate [471-34-1], siHca [7631-86-9], barium carbonate [513-77-9], and calcium tungstate [7790-75-2]. An organic peroxide, eg, benzoyl peroxide, capable of generating free radicals is also present (see Initiators Peroxides, organic). 

Once a metal surface has been conditioned by one of the above methods, a coupling agent composed of a bifimctional acid—methacrylate similar to a dentin adhesive is appHed. This coupling material is usually suppHed as a solvent solution that is painted over the conditioned metal surface. The acidic functional group of the coupling molecule interacts with the metal oxide surface while the methacrylate functional group of the molecule copolymerizes with the resin cement or restorative material placed over it (266,267). 

Epoxy resin cements are specifically intended for resistance to caustic alkalis and organic solvents, but they also have fair acid resistance. They have excellent bond strength to other materials including ceramic and concrete. The corrosion resistances of the cements described above are given in Table 3.40. 

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. ... 

Harz-saure, /. resin acid, resinic acid, -aeife, /. resin soap rosin soap, -sikkativ, n. rosin drier, -spiritus, m. rosin spirit, -spur, /. trace of resin or rosin, -stippe, /. (Paper) rosin speck, rosin spot, -stoff, m. resinous substance, -talgseife, /. tallow-rosin soap, yellow household soap, -tanne, /. pitch fir. -teer, m. resinous tar. -wasser, n. resin water, -zahl,/. resin number rosin number, -zement, m. resinous cement, haschen, v.t. tk i. eatch, seize, haschieren, hatch hash, mince. 

Resin cements Many different resin cements are now available, and types which give satisfactory service under most conditions can be obtained . 

Another development has been the advent of the dual-cure resin cements. These are hybrids of glass polyalkenoate cements and methacrylates that set both by an add-base cementation reaction and by vinyl polymerization (which may be initiated by light-curing). In these materials, the solvent is not water but a mixture of water and hydroxyethylmethacrylate which is capable of taking dimethacrylates and poly(acrylic add)-containing vinyl groups into solution. In the absence of light these materials set slowly and... 

Resin cements or polymer cements have been reviewed by Chandra, Justnes, and Ohama [343]. Polymer cements are materials made by replacing the cement at least partly with polymers. Cements can be modified by latex, dispersions, polymer powders, water-soluble polymers, liquid resins, and monomers. 

Resin binders, 17 477 for abrasives, 1 13-14 Resin-bonded refractories, 21 503—504 Resin bonding, 17 508 Resin cements, 12 746 Resin components, 10 385 Resin composite restorative materials, 8 333-335... 

Alfane Epoxy resin cement Atlas Minerals... 

Nukem Acid-resistant resin cements Amercoat Corp. 

Sharp silica sand is used as a filler in resinous cement mortars and to provide an abrasive surface in polymers. Reactive silica ash, produced by burning rice hulls, and a lamellar filler, novaculite, which is obtained from the novaculite uplift in Arkansas, are also used as silica fillers in polymers. 

Synthetic resin cements withstand hydrochloric acid, dilute nitric acid, dilute sulfuric acid, and dilute bases, and are frequently more resistant to organic liquids than is rubber latex cemenl. The adherence to ceramic materials is good, and the liability to cracking less than for sodium silicate cement. 

Structural tile construction and tile lined steel construction are commonly used in the paper mill to handle the pulp and to handle the paper mill chemicals. The tile affords a relatively smooth surface, it will not contaminate the pulp, and is resistant to chemical corrosion. The tile can be set in Portland cement mortar, however, a resin mortar is frequently preferred since it will be more resistant to a broader range of chemicals. Resin cements also have greater strength and are somewhat more resistant to erosion. 

A red shale brick or quarry tile floor is usually installed over a hot or cold applied mastic membrane. The mastic is applied to the concrete floor then the brick or tile are set with a resin cement. The resin cement can be a furan, a polyester or an epoxy depending on the anticipated exposure conditions. If high temperatures and constant exposure to aggressive chemicals are anticipated, the brick or tile will be bedded in the mortar as well as having mortar joints. 

Zirconia-based materials are very strong and fracture-resistant . In addition, these materials bond well to resin cement when the surface is properly treated or primers are used ". Thus in recent years zirconia-based materials have come to be widely used for making the frameworks of all-ceramic dental restorations. 

Objections to the high exotherms in the curing of furan resinous cements was overcome by substituting epoxy resins for the liquid furan prepolymer. The epoxy resins which were developed in I934Z, were intruduced originally as resinous cements and grouting materials under the trade names of Alfane and Furnane in the early 1950 s.—... 

In contrast to the phenolic, urea and furan resinous cements, the liquid epoxy resin in the epoxy cements is cured by a reaction with a polyfunctional amine, such as polyethyleneamine or an active polyamide (Versamid) which is dispersed in the carbon or silica filler as shown in the following equation. ... 

Epoxy resin cements have been used to seal leaking metal gas plpesil and for many civil engineering applications, such as steel wire-reinforced epoxy resin cements— and the reconstruction of the Abu-Simbul Temple in Egypt.— Epoxy resin cements whose physical properties are similar to those of concrete— are discussed more completely in Chapters 3, 4 and 5. 

These resin cement systems require only moderate capital investment, yet can yield dramatic results. For example, the many thousands of cracks in the Los Angeles City Hall produced by the 1971 earthquake were repaired by the use of 20 thousand gallons of an aluminum and ceramic filled epoxy resin mortar.— Likewise, wood whose cracks have been sealed by polyurethane mortars is suitable for continuous lathe cutting for veneer manufacture. 

It is important to point out that in spite of the ease of use, these resinous mortars, like many other chemical compositions, are toxic and adequate precautions must be taken to protect the health of the applicators. For example, the skin should be protected from the setting agents used in phenolic, urea, furan, and epoxy cements and adequate ventilation should be provided during the application of polyurethane and polyester cements to prevent the inhalation of volatile isocyanates and styrene respectively. However, once they are cured, these resinous cements are not hazardous. Actually, they are important energy conserving materials of construction. 

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