Polyurethane Adhesives and Sealants

PUR-Technology Centre of Excellence, Wolfson School of Mechanical and Manufacturing Engineering, Loughborough University, Loughborough, Leicestershire, LEI 1 3TU, UK 

Andrew D. Nurse completed his PhD in 1990 at the University of Sheffield. His postdoctoral research was performed at University of Sheffield until 1992. He has been a senior lecturer in stress analysis in the Department of Mechanical Engineering, Loughborough University, since 1993. His research interests include new manufacturing processes for plastics, knowledge-based engineering, and inverse analysis. He is director of a Centre of Excellence in polyurethanes. 

Keywords Additives Aliphatic Aliphatic isocyanates Amine-isocyanate reaction Aromatic isocyanates Blocked isocyanates Chain extenders Construction (application in) Glass transition temperature Hydroxyl-isocyanate reactions Hot melt reactive PU Isocyanates MDl Moisture curing PU One-component PU Packaging (application in) Plastic and composites (application in) Polyester Polyether polyols Polyisocyanates Sealants Silane PU hybrids TDI Testing of PU adhesives testing of PU sealants Testing standards TPU thermoplastic PU Transportation (application in) Two-component PU Water-borne PU 

Polyurethane adhesives and sealants are part of the polyurethane family legacy that emerged in 1937 when Bayer et al. pioneered the polyaddition polymerisation 

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R. P. Deltieure, "Polyurethane Adhesives and Sealants," Proceedings of Caulks and Sealants Short Course II, The Adhesive and Sealant Council, Rosemont, hi., 1992. 

Polyurethane Adhesives and Sealants. Polyurethane adhesives are known for excellent adhesion, flexibility, toughness, high cohesive strength, and fast cure rates. Polyurethane adhesives rely on the curing of multifimctional isocyanate-terminated prepolymers with moisture or on the reaction with the substrate, eg, wood and cellulosic fibers. Two-component adhesives consist of an isocyanate prepolymer, which is cured with low equivalent weight diols, polyols, diamines, or polyamines. Such systems can be used neat or as solution. The two... 

The two-component products (structural epoxydes, polyurethane adhesives and sealants, other two-component sealants) may be extruded from two-component cartridges (Fig. 15) and then mixed in a mixing device called static mixer immediately at the exit of the cartridge. 

Polyurethane adhesives and sealants these products are delivered in aerosol cans which deliver a bead of the product, of 3 to 5 mm diameter. The product foams immediately after extrusion so that the head swells up to 20 times of the original volume. 

The chemistry of polyurethane adhesives and sealants has been explained in the Chapter 3 of Volume 1 and readers may refer to this chapter for further information. 

For more informations about PUR adhesive and sealants, our read s may refer to the chapter Chemistry of Polyurethane adhesives and sealants in Volume 1 of this Handbook. 

Apart from the development of polyurethane adhesives and sealants with isocyanate reactive groups, a new type of silane-terminated polymer adhesive has been developed called Polyurethane (PUR)-Hybrids. They and modified silicones (MS) and provide the benefits of ... 

In the early 1980s, Sika diversified into the chemistry of elastic adhesive bonding for industrial applications. With eight production centres in three continents, Sika is now the world s largest manufacturer of one-component polyurethane adhesives and sealants. The customer oriented solutions and services of the Sika Industry Division are marketed to the following market sectors, where they are the leaders in their field ... 

In Volume 1, we have provided general information about adhesives and sealants with the chapters Technical Characteristics of Adhesives and Sealants , Surface Preparation before Bonding and Polyurethane Adhesives and Sealants . 

Chapter 1 Construction Sealants, by Philippe Cognard, including technical characteristics, different chemical types, applications in building, standards and regulations. This chapter will complement the chapters Silicone Adhesives and Sealants, MS Polymer Adhesives and Sealants, Polyurethane Adhesives and Sealants, Civil Engineering Sealants, which will be discussed in Volume 3 and also in later volumes. 

Chapter 3 Polyurethane adhesives and sealants, by scientists of Loughborough... 

Many other adhesives and sealants manufacturers also offer polyurethane adhesives and sealants, but I have limited this list to a few leaders in this field. A very large list of some 150 major adhesives and sealant manufacturers, located in all major countries, is provided elsewhere in this handbook. 

A variety of different polyols are used in the production of different specifications of polyurethane adhesives and sealants. Polyols are either polyesters or polyethers. In most prepolymers the polyols will consist mostly of both diols and triols. 

Table 4 Isocyanates series trademarks for polyurethanes adhesives and sealants.

Table 5 Principal polyisocyanate products used for polyurethane adhesives and sealants.

Chemistry of Polyurethane Adhesives and Sealants 115 Table 6 Common initiators for poly ether polyols. 

Some requirements which are common to both polyurethane adhesives and sealants are [24, p. 23] ... 

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