Curing automotive applications

To improve on penetration and heat resistance (properties normally in opposition when formulating hot melts), reactive hot melt systems are being developed. Moisture curing urethanes have already gained wide acceptance in a number of wood and automotive applications. UV cure is slowly gaining acceptance in PSA, labeling, and other markets. 

Moisture-curing hot melts are a small but fast growing segment of the urethane adhesive market. They are used mostly in construction and furniture assembly applications. Recent applications include RV sidewall assembly and other OEM automotive applications. Smaller applications include bookbinding and footwear. A typical adhesive is shown below ... 

The development and optimisation is described of a new curing system to replace lead-based compounds used in epichlorohydrin elastomers currently used in automotive applications. The system is based on 2,4,6-trimercapto-1,3,5-triazine and dialkyldithiophosphate, which is shown to produce a scorch-safe curing system and which confers excellent physical and ageing properties on epichlorohydrin rubbers. Trials are conducted in formulations for multilayer fuel hoses. 9 refs. 

The use of plastics in automotive applications has expanded considerably over the past 20 years. In 2001, approximately 2501b of plastics were used per automobile compared to less than 100 lb five years earlier. With the increased use of plastics, coating research has concentrated on the painting of these often difficult substrates. Among the numerous prerequisites for coatings on plastic are wetting of the substrate uniform film development a cure response below the heat distortion temperature of the plastic adhesion to the sub-... 

III), respectively, were thermally cured and used as seals in high temperature automotive applications. 

JOHNSON, MORRIS. EB-Cured Composites for Automotive Applications. RadTech Report, November/December (2001) 41-42. 

In general, standard industrial cyanoacrylates do not operate effectively above 180°F (see Fig. 4). However, the new allyl types of cyanoacrylates can operate as high as 480°F before the bond loses sufficient strength to be operationally effective (see Table 2). Allyl cyanoacrylates for metal-bonding applications have proven effective in wave solder and under-hood (automotive) applications. In Fig. 4, bonded assemblies are cured at room temperature for 24 h. The assemblies are heated for 2 h and tested hot. 

The GMA clear coatings have outstanding exterior durability, hence their acceptance in the automotive sector (see Fig. 2). Pigmented GMA acrylic powders have not foimd widespread use in market areas other than automotive, eg, architectural applications. Hydroxyl functional acrylic resins cured with blocked isocyanates or uretdione-based curatives have also found use in automotive applications and their exterior durability is only somewhat less than that of the GMA acrylic powders (50). Carboxyl functional acrylic resins are also commercially available. They can be cured with TGIC for exterior applications or with bisphenol A epoxy resins. The latter combinations are sometimes called acrylic-epoxy hybrid coating powders and are noted for their excellent hardness, stain, and chemical resistance. They find use primarily in appliance coatings (79). 

Schubel P J, Parsons A J, Lester E H, Warrior N A, Rudd C D (2006) Characterisation of thermoset laminates for cosmetic automotive applications Part II - Cure and residual volatile assessment . Composites Part A, 37, 1747-1756. 

True properties are determined by the polymer and compound formulation and, for synthetic rubbers, additionally by type of curing agents such as sulfur or peroxides and the state of vulcanization. Typical properties for four polymers often used in automotive applications [acetals, nylons, polycarbonates, and unsaturated polyester (vinyl esters)] are shown in Tables 10.1 through 10.4. Typical property data is readily available from resin producers and compounders. Property data for elastomers is found in the chapter on elastomers in this handbook. 

Sealants and adhesives are used widely in automotive applications. One of the advantages of an automotive production line is that the high-temperature (160-205 °C) paint bake ovens can be used to cure the adhesives and sealants. 

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