Adhesion of polyurethane

Figure 8.54. Effect of filler type on adhesion of polyurethane adhesive. [Adapted, by permission, from Oien H T, Polyurethanes 95. Conference Proceedings, Chicago, II., 26th-29th Sept.1995, 137-41.]...

Figure 7.5 Effect of ageing at 50 °C, 50% RH on lap-shear adhesion of polyurethane/ PVC (a) and polyurethane/ABS (o) joints. Polyurethane adhesive cured according to...

Improved adhesion of polyurethanes to metals has been claimed to be achieved by incorporating phosphoryl compounds or silane coupling... 

Figure 5. Measurements by Maugis Barquins (4)of the rate dependence of the adhesion of polyurethane rubber, compared with the Schapeiy theory for a 3-parameter solid (equation (18)). (Reproduced with permission from reference 4. Copyright 1978 Institute of Physics.)...

Silicone fluids (polydimethylsiloxane) and silicone resins are in popular use in polyurethanes. They are usually applied from solvent-based systems. Figure 11.32 shows that silicone fluids having lower viscosity require less force to remove molding (the blister method was used to measure adhesion of polyurethane to the mold material). Figure 11.33 shows that 92% of silicone was absorbed by polyurethane and only 8% was detected by ATR-IR. This absorp-... 

Reegen, S. L., and Ilkka, G. A., The Adhesion of Polyurethanes to Metals, Adhesion and Cohesion Symposium, General Motors Research Laboratory, Elsevier, 1962. 

The physical properties of polyurethane adhesives result from a special form of phase separation which occurs in the cross-linked polyurethane stmcture. The urethane portions of polyurethanes tend to separate from the polyol portion of the resin, providing good shear strength, good low temperature flexibiUty, and high peel strength. Catalysts such as dibutyltin dilaurate [77-58-7], stannous octoate [1912-83-0], l,4-diazabicyclo[2.2.2]octane... 

Adberabibty of the film may be enhanced by its treatment with flame, electric discharge, boron trifluoride gas, activated gas plasma, dichromate sulfuric acid, and a solution of alkab metal ia Hquid ammonia (84—87). A coating of polyurethane, an alkyl polymethacrylate, or a chlotinated adhesive can be apphed to PVF surfaces to enhance adhesion (80,88,89). 

Polymers. AH nitro alcohols are sources of formaldehyde for cross-linking in polymers of urea, melamine, phenols, resorcinol, etc (see Amino RESINS AND PLASTICS). Nitrodiols and 2-hydroxymethyl-2-nitro-l,3-propanediol can be used as polyols to form polyester or polyurethane products (see Polyesters Urethane polymers). 2-Methyl-2-nitro-l-propanol is used in tires to promote the adhesion of mbber to tire cord (qv). Nitro alcohols are used as hardening agents in photographic processes, and 2-hydroxymethyl-2-nitro-l,3-propanediol is a cross-linking agent for starch adhesives, polyamides, urea resins, or wool, and in tanning operations (17—25). Wrinkle-resistant fabric with reduced free formaldehyde content is obtained by treatment with... 

In 1993, a total of over 6 x 10 t of polyurethanes were consumed worldwide (Table 8). The flexible foam market in the United States totaled 932,000 tons in 1994. Flexible slab foam is used predominantly in furniture, carpet underlay, and bedding molded foam is used extensively in transportation. Carpet underlay is manufactured from either virgin or scrap polyurethane foam, which is combined with a binder adhesive. The consumption of flexible polyurethane foam in the various U.S. markets in 1994 is shown in Table 9. 

Some grades of polyurethane and polyester copolymers are used as hot-melt adhesives. AppHcations include shoe manufacture and as an adhesive interlayer in coextmsion. 

Aqueous dispersions of polyurethanes have also become available which may be used instead of solutions in organic solvents for such applications as leather treatment, adhesives and surface coatings. 

The finite size effects in the contact between a spherical lens of polyurethane and a soft flat sheet of crosslinked polyfdimethyl siloxane) (PDMS) has been addressed by Falsafi et al. [37]. They showed that for deformations corresponding to contact diameters larger than the sheet thickness, the compliance of the system was affected by the glass substrate supporting the soft sheet. In order to minimize the finite size effects in the adhesion measurement of small elastomeric lenses, Falsafi et al. [38] and Deruelle et al. [39] used relatively thick elastic sheets to support their samples. 

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