Building construction adhesives

The use of adhesives in building construction imposed exacting requirements upon quality and application techniques [92] - [98]. In addition to durability and resistance to mechanical stress, temperature and weather resistance are prime requirements. In prefabricated construction, the use of adhesives was an important requirement for efficient assembly techniques. 

Prefabricated Construction. Sandwich elements are widely used in prefabricated construction. In this case, bonding must meet stringent requirements with regard to stability and durability, especially in the case of exterior wall elements. Deflections attributable to difierential temperature or moisture-induced expansion or contraction can amount to as much as 5% of the length. The adhesive layer must be permeable to water vapor or act as a water barrier, depending on the structure and function of a given element. The adhesives used are two-component reactive resins, based mainly on epoxy resins, but polyurethane resins are used as well, as are elastomer-based contact adhesives that are applied on both sides. 

With building components based on synthetic resin concrete (polymer concrete), the cement may be replaced partly or completely by organic binders, such as co- or terpolymeric vinyl acetates, acrylates or epoxy resins. Such systems are described as 

Low-viscosity reactive resins are used to seal cracks in concrete constructions. These epoxy and polyurethane resins show excellent creepability and bond strength to concrete. 

For applications such as swimming pools and water-purification tanks, for which chemical resistance is required, or where resistance to dynamic stress is needed, special epoxy resins are used. Blends of a waterborne synthetic emulsion with a cement compound are suitable for applications with lower requirements. In some cases, e.g. sewage-treatment plants, elastomer-modified bitumen mortars are still used. 

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DIN 52 455, part 1 1975 Testing of sealing materials for sealing and glazing in building constructions adhesion and cohesion test pretreatment in controlled atmosphere and in water. 

DIN 52 455, part 2 1974 Testing of sealing and glazing compounds in building constructions adhesion and extension test cyclic conditions. 

Solvent-based adhesives, two-component epoxy resin adhesives, two-component methacrylates for assembly purposes (priming, filling, smoothing, sealing, etc.) For these applications, a multitude of so-called building/ construction adhesives is commercially available. 

Thermoplastic rubber is a relatively new class of polymer. It has the solubility and thermoplasticity of polystyrene, while at ambient temperatures it has the toughness and resilience of vulcanized natural rubber or polybutadiene. These rubbers are actually block copolymers. The simplest form consists of a rubbery mid-block with two plastic end blocks (A-B-A), as shown in Figure 5.7. Examples of commercial products are Kraton and Solprene . These materials are often compounded with plasticizers to decrease hardness and modulus, eliminate drawing, enhance pressure-sensitive tack, improve low-temperature flexibility, reduce melt and solution viscosity, decrease cohesive strength or increase plasticity if desired, and substantially lower material costs. Low levels of thermoplastic rubbers are sometimes added to other rubber adhesives. These materials are used as components in the following applications PSAs, hot-melt adhesives, heat-activated-assembly adhesives, contact adhesives, reactive contact adhesives, building construction adhesives, sealants, and binders. Two common varieties of thermoplastic rubber adhesives are styrene-butadiene-styrene (S-B-S) and styrene-isoprene-styrene (S-I-S). ... 

Although the primary function of sealants is to seal, adhesion promoters are often added, which allows them to adhere to the adjoining base materials. It is therefore sometimes difficult to distinguish between an adhesive and a sealant. For example, structural silicone adhesives are used in the building construction industry owing to their sealing, adhesive, elastomeric properties, and their resistance to harsh environmental conditions [67,70,77]. 

SS-LINKED POLYMERS ARE USED in a wide variety of aerospace, automotive, building construction, and consumer product applications. Not all paints, adhesives, composites, and elastomers are cross-linked, but cross-linking systems are often used in these applications when resistance to solvents, resistance to high temperatures, and high mechanical performance are required. These important properties can be traced directly to the three-dimensional interconnected molecular network that is characteristic of cross-linked systems. 

ISO 9046 1987 Building construction sealants - determination of adhesion and cohesion properties at constant temperature. 

This test method is useful in determining the effect of using adhesives on rigid cellular polystyrene (RCPS) foam in building construction. The method covers a practical means of measuring the degree of foam cavitation damage when an adhesive is used to bond these foam substrates. 

Use Food packaging, sporting goods, wire and cable, building construction and automotive. More recent uses are extrusion laminations, in extrusion coatings, and as adhesive films and webs for thermal laminating and other new uses not related to packaging. 

Major polymer applications surface protective coatings (protective and decorative - automotive, metal cans, industrial flooring, anticorrosive paints), electrical/elec-tronics (printed circuit panels, conductive adhesives), composites (building/construction, marine, electrical/electronics, aircraft, communication satellites, automotive, pipes, consumer products), bonding and adhesives, flooring, tooling and casting, biosensors... 

Resorcinol-based adhesives are used extensively to bond structural grade, exterior laminated beams for building construction (see Chap. 29 on Resorcinol Adhesives). The coldsetting adhesives which dominate this field are based on phenol-resorcinol-formaldehyde (PRF) resins. The adhesive itself is composed of the PRF resin and a hardener that includes formaldehyde, often in the form of paraformaldehyde mixed with inert fillers. The performance of the resin is resorcinol dependent. The cost of the resin is also resorcinol dependent as this is a very expensive chemical produced industrially in only three locations in the world. The research work on these resins from their inception has then been based on the optimization of their bonding performance coupled with the decrease in the relative percentages of resorcinol used. It has the been a long and successful work of empirical research and development which still continues. 

Epoxy resin, as an adhesive, is nsed for many applications in building/construction, (i.e., it is possible to bond a new rebar to existing steel in concrete instead of welding it, by use of special epoxy adhesives). Epoxy can bond to almost any material (for strnctural or non-structural bonding) with high adhesive strength in various environments and temperatures. In civil engineering applications, epoxy adhesives are used to bond concrete in a number of different ways. Epoxy can be used to bond plastic concrete (or wet concrete) to cured concrete, it can be used to bond cured concrete to cured concrete, or cured concrete to cracked concrete, as well as to bond cured concrete to other materials with similar or dissimilar thermal expansion coefficients and elastic moduli. 

Flemming, C. J. and King, G. E. M. (1967), The development of structural adhesives for three original uses in South Africa , Proceedings of RILEM Symposium on Resins in Building Construction, Paris, September 1967, pp. 75-92. 

Adhesives 4 Repair kits, structural adhesives for buildings and construction, adhesives for cars, boats and aircrafts, optics, fiber optics, optoelectronics... 

Adhesives Sealants in Building Construction. London, Feb.22, 1988, Paper 1. 62Bu-6A SERVICE EXPERIENCE OE ADHESIVES AND SEALANTS IN BUILDING... 

RF resin is also used to make fast-curing adhesives for laminated timber and beams as well as adhesive applications in building construction. 

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