Sealant types

Another way to determine durabHity is to find successfuHy sealed, existing field instaHations. Sealant manufacturers often have case histories of successful instaHations. Adhesion performance can vary widely with sealant type, substrate type, and cleaning method. Eor this reason, it is important to understand the sealant s sensitivity to cleaning practices. Often with difficult-to-adhere substrates, a primer is used. Sealant manufacturers can provide recommendations as to which substrates require primers, what type of primers should be used, and how they should be appHed. 

The tandem coating line seen in Lig. 8.2 can be used to reduce the cost of producing products that require both laminating and coating, such as a paper/poly-ethylene/foil/sealant type of structure. If this product is made in two passes through the machinery, the cost is higher because of the increased cost of handling the materials twice and the increased start-up and shut-down waste. 

Sealant type Maximum tolerated Character Typical uses Comments Expected... 

Note (1) Sealant types are listed in order of increasing initial cost the list does not claim to be comprehensive. (2) Gun-grades are listed for joints in horizontal surfaces, the following self-levelling types are available (a) hot-poured bituminous and rubber/bitumen (b) cold-poured polysulphide and polyurethane. 

An explosion occurred during the repair of a tyre which had previously been inflated using a sealant-type tyre inflator. The result of the ensuing legal action is reported, together with summaries of other similar explosions/fires, collated by the victim s lawyer. The volatility threshold appears to be reached at very low concentrations. 

Application of Water-Swelling Rubbers as Sealants Types of Sealants 296... 

As early as 1982, Riesen and Bartelst ] demonstrated the usefulness of dynamic load thermomechanical analysis (DLTMA) for the characterization of commercial joint sealants for building construction. They used DLTMA to study the viscoelastic behavior of four different sealant types polysulfide, polyurethane, silicone, and polyacrylate. The difference in viscoelastic behavior of the sealants can be seen from Fig. 8. 

In determining the appropriateness of a sealant or caulk for an application, many factors need to be considered. The generic polymer technology, the physical form, sealant classification, specifications and performance properties are all important features of a sealant or caulk. Table 22 outlines some basic performance properties of the sealant types reviewed in this chapter. As seen in Table 22, most of these sealant types are utilized in construction applications. As described earlier in this chapter, sealants and caulks can be classified in low, medium, and high movement categories, and selection is primarily decided on the basis of movement capability, adhesion, life expectancy, and material cost. Table 23 reviews the typical applications for these types of sealants and caulks. 

Important cure related considerations for evaporative and chemieally reactive adhesive and sealant types inelude ... 

O Section 12.2 of this chapter classifies adhesives according to functional types including, structural, hot-melt, pressure sensitive, water-base, ultraviolet/electron beam cured, conductive, high-temperature, and sealant type. 

Fig. 7.24 Microstructure of the cross-section of alloy T-1 a and alloy T-2 b with glass sealant type B after 400 h of exposure in hydrogen at 800°C (Haanappel and coworkers 2005)...

Sealants, while sharing many similarities with adhesives, tend to be made from different materials and include those based on polysulfides (often for uses in contact with fuel), silicones, polyurethanes, acrylics in both solvent-based and latex-based materials, and sealants based on butyl and fluorocarbon polymers. In addition to adhesive and sealant types, this chapter reviews methods for testing and qualifying these materials. 

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