Nonstructural adhesives

Adhesives commonly used on thermosetting materials include epoxies, urethanes, cyanoacrylates, thermosetting acrylics, and a variety of nonstructural adhesive systems. The following discussion includes a very brief description of various thermosetting substrate materials, the properties that are critical relative to epoxy adhesion, and any special processes that should be noted for the particular substrate. 

Films. Both structural and nonstructural adhesives are commonly available in film form. Adhesives applied in the form of dry films offer a clean, hazard-free operation with minimum waste and excellent control of film thickness. However, the method is generally limited to parts with flat surfaces or simple curves. Optimum bond strength requires curing under heat and pressure, which may involve considerable equipment and floor space, particularly for large parts. Film material cost is high in comparison to liquids, but waste or material loss is the lowest of any application method. 

Nonstructural—adhesives that are soft and relatively weak often used for temporary fastening Chenucal composition... 

Nonstructural adhesives are not required to support substantial loads but merely hold lightweight materials in place. Nonstructural adhesives are sometimes referred to as holding adhesives. They are generally represented by pressure-sensitive, contact, and hot-melt adhesives. Sealants usually have a nonstructural function. They are principally intended to fill a gap between adherends to provide a seal without having high degrees of adhesive strength. 

There are numerous families of adhesives within the structural and nonstructural types. The most common chemical families of structural and nonstructural adhesive famihes for bonding plastics are identified in Table 7.14. 

Nonstructural adhesives are those having bond strength that is less than 1000 psi but sufficient for applications such as pressure sensitive tapes, labels, laminates, and so on. Nonstructural adhesives are usually employed where production speed, convenience, and high peel strength are required. They generally have sufficient permanence for the applications mentioned. 

Nonstructural adhesives are adhesives with lower strength and permanence. They are generally used for tanporary fastening or to bond weak substrates such as paper and foam. Examples of nonstructural adhesives are pressure-sensitive tapes, wood glue, elastomers, and sealants. These adhesives are sometimes used for temporary fastening or sealing. 

Antirutsch... nonsmoking rauchfrei nonspecific unspezifisch nonstructural adhesive Klebstoff ftlr... 

Nonstructural adhesives are characterized by low shear strength (usually less than 1000 lb/ in ) and poor creep resistance at slightly elevated temperatures. The most common nonstructural adhesives are based on elastomers and thermoplastics. Although these systems have low strength, they usually are easy to use and fast setting. Most nonstructural adhesives are used in assembly-line fastening operations or as sealants and pressure-sensitive tapes. 

In contrast to other traditional mechanical joining methods such as riveting, welding, and screwing, adhesive bonding has httle or no adverse affect on the material characteristics of the surfaces to be joined. However, in general, in the area of nonstructural adhesives, designers do... 

This chapter describes and discusses the main factors affecting the durability of nonstructural adhesives and sealants, and the methods used for their estimation, and their applicability to actual service life prediction. The major conclusions that can be drawn are the following ... 

Structural adhesive types recommended are epoxy (up to 71°C), polyester with isocyanate-curing agent (up to 121°C), and cyanoacrylate (up to 82°C). Structural adhesives for bonding acetal copolymer to itself have yielded shear strengths of 4.1—5.5 MPa. Nonstructural adhesives are usually... 

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