Acrylics in the Construction Industry

In this book I have confined discussion to those polymeric materials which are cured by chemical reaction and which have found widespread application in the construction industry. As such, the book covers materials based on epoxies, polyurethanes, silicones, polysulphides, alkyds and polyesters. In addition, there is a chapter on hybrid polymer systems and one on acrylics. It is true that acrylic emulsions are not strictly thermosetting polymer systems, but their widespread use and importance made their exclusion difficult. These materials find use as coatings, sealants, adhesives, grouts, flooring compounds, repair compounds and waterproofing agents. 

Acrylic materials based on methacrylates and emulsions have captured a good market share in the construction industry. The properties that are useful for construction applications are ... 

THERMOSETTING POLYMERS IN CONSTRUCTION APPLICATIONS Table 5.1 Specific properties and applications of acrylic systems in the construction industry... 

Several other polymers such as polyurethanes, alkyds, acrylics, polyesters, silicones, etc. can be hybridised to improve the performance or to obtain desired end-results. The growth of hybrid polymer technology is giving rise to considerable improvements, and many hybrid systems have been introduced to the market. Most of the work reported in this field is for coatings, but at the same time it is useful for other products used in the construction industry. Research is under way by many polymer manufacturers and universities, and innovations are continuously being reported. In this chapter we shall be dealing with those combinations which are useful, or may be useful, for the construction industry. 

Acrylic glues used in the construction industry did not contain acrylics (detection limit 0.005%) (Table 5). The main component of the anaerobic glues was TREGDMA. DEGDMA or 2-HPMA were used as reactive diluents. Undeclared 2-HPMA was present (at 7.6%) in one glue (Product 55). 

When used for industrial adhesive purposes, epoxy resins occur mostly in the construction industry, the assembly of cars, ships, and aeroplanes, the manufacturing of sports equipment, as well as in the optical and electronic industries. Much is similar between the chemistry of epoxy resins and acrylates. Both are (often) two-component systems. They are not sensitising when fully cured but frequently contain an amount of remaining monomer, which is enough to... 

We will try to place each Chemical type chapter near to the chapter dealing with the Industry using these types of adhesives and sealants, so that each volume will focus on one main field for instance, in Volume 3 that will be devoted to Construction, we will study the adhesives for construction, civil engineering, the silicone sealants, the woodworking and furniture adhesives, acrylic adhesives and sealants. Those working in the construction industry can then get fairly complete information from that volume. However, construction... 

The polyester resin may be modified with methyl methacrylate resins for better clarity and transparency. Recent developments involve the use of acrylates or polyvinyl flnoride as surface coatings bonded to the laminate for longer gloss retention. The prodnct is cnred at ambient temperatures, although heat will accelerate the cure and ensure a more satisfactory laminate. The same procedures are also followed in producing epoxy-resin laminates, although these are not as widely used in the construction industry. 

Contact adhesives are preferred for the plastic laminate materials. Contact cements are available in three types water base, flammable solvent base, and chlorinated solvent non-flanunable base. The vast majority of these contact cements utilize neoprenes as the basic elastomer. Attempts have been made by some manufacturers to formulate acrylic contact cements, but as of this writing none of these are in general use in the construction industry. 

PMMA is the most common member of the acrylic family and widely known as the ICI trade name of Perspex . Acrylic has excellent transparency and no appreciable yellowing under sunlight. They are therefore used in the construction industry and in the electrical industry for lighting systems and lenses. 

Another important application area for PSAs in the electronic industry focuses on the manufacturing, transport and assembly of electronic components into larger devices, such as computer disk drives. Due to the sensitivity of these components, contamination with adhesive residue, its outgassing products, or residue transferred from any liners used, needs to be avoided. Cleanliness of the whole tape construction becomes very critical, because residuals like metal ions, surfactants, halogens, silicones, and the like can cause product failures of the electronic component or product. Due to their inherent tackiness, acrylic PSAs are very attractive for this type of application. Other PSAs can be used as well, but particular attention has to be given to the choice of tackifier or other additives needed in the PSA formulation. The choice of release liner also becomes very critical because of the concern about silicone transfer to the adhesive, which may eventually contaminate the electronic part. 

Another class of acrylic sealants arc the solvent-releasing acrylics. Acrylic monomers are polymerized in a solvent. The natural adhesion of most of the solvent-releasing acrylics produces some of the best unprimed adhesion in the sealant industry. However, slow, continual cure generally produces large compression sets and limits their use to low movement applications. Also, the relatively high amounts of solvent and traces of acrylic monomer in these formulations limits their use to outdoor applications, usually in construction,... 

Among the countless number of applications of polymers, the construction industry is one which utilises several polymeric materials. In this book I cover those polymeric materials which are single or bicomponent systems and are cured at ambient temperature either with the aid of curing agents or atmospheric moisture. The various polymers used in manufacturing such products include epoxies, polyurethanes, acrylics, silicones, polysulphides, alkyds and polyesters. As a result of innovation, new technologies exist which utilise more than one polymer in a single product. Such systems are discussed in Chapter 10, on hybrid polymers. 

In spite of vast research work on PUD-acrylic hybrids, a limited range of hybrids is currently available. Among the various systems, two types are of interest to the construction industry. The first type is suitable for concrete protection, in the form of coatings. The second type finds suitability for wood finishes for parquet floor lacquers. 

Poly sulfide rubber was first produced in 1929, and the liquid polymers were used in sealants and as flexibilizers for epoxy adhesives around 1950. In 1952 the polysulfide sealant was introduced to the construction industry [11, p. 74]. In the 1950s the first butyl rubber caulks appeared in the construction market [11. p. 108] and latex caulks [vinyl acrylic and poly(vinyl acetate)] appeared sometime after 1956. 

PCM are important, because they are latent heat storage materials suitable for the construction industry as low-energy alternatives to air-conditioning systems. Indeed, a material series made of wax entrapped into microcapsules of acrylic glass (Micronal) and integrated in conventional construction materials such as gypsum plaster is already commercialized by BASF. ... 

The first products were based on UV-cured acrylics with a thickness of 0.3 to a few millimeters filled with glass microbubbles [279]. This has been extended now to a range of products for various interior and exterior applications, e.g., in the construction, automotive, building, and electronic industries. Such performance can be achieved also by polyurethanes [280] and other elastomers. 

Preactivated and Water-Activated Types. A typical preactivated industrial-type zinc/air cell, the Edison Carbonaire cell, is manufactured in a 1100-Ah size and is available in two-and three-eell configurations, as illustrated in Fig. 38.12. The cell case and cover are molded from a tinted transparent acrylic plastic. The construction features are shown in Fig. 38.13 identifying the wax-impregnated carbon cathode block, the solid zinc anodes, and the lime-filled reservoir. These cells normally have a bed of lime to absorb carbon dioxide and to remove soluble zinc compounds from solution and precipitate them as calcium zincate. They are made with transparent cases so that the electrolyte level and the state of charge can be monitored visually. The state of charge can be monitored by observing the condition of the zinc plates and the condition of the lime bed. The bed turns darker as it is converted to zincate. 

Virtually no strucmral bonding in the aerospace industry is achieved using acrylic adhesives. However, they have found use in the construction of the Airbus A.320 flap track fairings where acrylic adhesives are seen as easier to use and apply than... 

Since the introduction of the first polysulfide sealants in the 1950s, the sealant market had grown by 1992 into a 1.4 billion industry. Sealant use is generally divided into four categories transportation, construction, consumer, and industrial. Table 9 lists the market segment value of each use as of 1992 and Table 10 the market share of the various material types. Continued growth is expected, especially for silicones, urethanes, and acrylics. Table 11 lists suppliers of sealants. 

Polystyrene is an inexpensive transparent plastic which is often used in industry for the fabrication of parts by injection moulding. However, the tougher acrylic plastics are preferable for the construction of laboratory apparatus. Polystyrene is soluble in many organic liquids and, if strain free, may be solvent-bonded by the use of chlorinated hydrocarbons, benzene, or toluene. Special impact-resistant grades are available which are less susceptible to solvents and thus a little harder to solvent-bond than the conventional material. Polystyrene also may be welded. 

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