Construction adhesive types

Epoxy adhesives have become the most recognizable structural adhesive type. They have found commercial success in demanding industries such as aerospace, automotive, building and construction, and electrical and electronic. Their ease of use has also encouraged their commercialization in the do-it-yourself markets, which has added to the exemplary reputation of epoxy adhesives. 

Adhesives. Acrylic emulsion and solution polymers form the basis of a variety of adhesive types. The principal use is in pressure-sensitive adhesives, where a film of a very7 low T (<—20° C) acrylic polymer or copolymer is used on the adherent side of tapes, decals, and labels. Acrylics provide a good balance of tack and bond strength with exceptional color stability and resistance to aging (201,202). Acrylics also find use in numerous types of construction adhesive formulations and as film-to-film laminating adhesives (qv). 

In terms of the system design of TDS, there are three types of system constructions reservoir type, matrix type, and drug-in-adhesive type. In reservoir type and matrix type, pressure-sensitive adhesive (PSA) is only expected to keep the system on the skin. Hence, the necessary conditions for adhesives are almost the same as those of bandages, namely, well skin adhesiveness and low skin toxicity whereas in drug-in-adhesive type, the drug is incorporated into the adhesive so that the interaction between drugs and the PSA is more critical, as discussed later. 

Traditionally, UF, MUF and PF adhesives have been the preferred adhesive systems for production of plywood worldwide. In the European market these adhesive types are still predominant. There are, however, a few producers using EPI adhesives for products where metal is included in the construction. 

Table 2. Some Adhesive Types Used in Construction Applications ...

Although thermoanalytical techniques have been widely used in the characterization of different types of adhesives, little work has been published on the use of these to characterize construction adhesives. 

Construction Adhesives. Much SBR latex is used in adhesives directed to the construction industry. Wall tile and vinyl floor tile adhesives are typical examples (see Table 3 for formulation). SBR latexes, both carboxylated and noncarboxylated types, are often added to cement mixtures to improve adhesion in repair work. Sealants and caulks can be based on SBR. 

Adhesives for ceramic tiles are specified by the standard EN 12004 2007 (Adhesives for tiles. Requirements, evaluation of conformity, classification, and designation), and includes performance requirements for cementitious, dispersion, and reaction resin adhesive types for all internal and/or external wall, floor and ceiling applications. Annex ZA, of this standard, sets out the requirements, which address the provisions of the Construction Products Directive (see O Sect. 35.4 below), and include assessments of durability. Compliance with these requirements confers a presumption of fitness for purpose for the applications and form part of a CE mark. In these cases durability is assessed by elevated temperature and/or water immersion accelerated ageing or freeze-thaw cycling of test specimens and then determining tensile or shear adhesion strength against minimum requirements. 

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. 

Instead of using a single layer of adhesive, tapes with two layers of adhesive, which can be of the same or different type, have also been constructed. Here, a thin film backing may be used as the central layer of the tape, with the adhesives coated on each side of the backing. This type of tape construction is commonly referred to as a double-stick or double-faced tape. 

The primary non-woven applications for hot melts are in disposable articles such as diapers and sanitary napkins (see Fig. 22). These articles are made by high speed processes and are immediately packaged in sealed plastic bags, thus they are prime candidates for hot melt use. The applications are broken down into three categories, requiring three different types of adhesives construction, elastic attachment, and garment attachment. 

As adhesives they are very widely used both as cold setting and thermo curing. They can bond together a large variety of surfaces including metals. Araldite resins of this type are used widely in aircraft construction. They are also used for bonding concrete in dams and joining teflon film to stainless steel. They are used to encapsulate delineate electrical parts to protect them from shock and moisture. Such parts are used in components of rockets and satellites. 

Hancox, L. S., Yeh, K. S., and Clegg, S. (1997). Construction and characterization of type 1 non-fimbriate and non-adhesive mutants of Salmonella typhimurium. EEMS Immunol. Med. Microbiol. 19, 289-296. 

Adhesion on HLORIN -type fibers, has been studied as a function of five process factors. The names of factors, with their variation levels, are shown in Table 2.32. Matrix 23 of full factorial experiment has been used in constructing random balance matrix. The design matrix by the method of random balance with experimental results is shown in Table 2.33. Note that each design point was repeated 20 to 50 times due to high non reproducibility of the system. 

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