Mixers, adhesives sealants

Acrylic latex sealants. Basic acrylic latex sealant formulations were compounded in a sigma blade mixer, as shown in Table 3. The water-borne silanes were then incorporated into a base. Standard wet and dry peel adhesion determinations from various substrates were performed periodically in accordance with ASTM C794-8. 

For mechanical mixing often a variable-speed mixer, preferably air-driven, and a container are all that is required. An air-driven mixer is safer, less costly, and more easily regulated than an electrically driven mixer. For the most reliable mixing operation, the temperature of the compound in the mixing vessel should be uniform. For adhesives or sealants that are stored at cold temperature, adequate mixing viscosity can be reached quickly by the use of a hot liquid jacket around the vessel. 

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. 

Figure 9.12 Structural bonding application for a reinforced plastic bumper assembly for a truck. The equipment dispenses a two-component structural adhesive onto the bumper assembly before it is integrated into the truck. In production, this is typically done robotically with a manual backup system (shown). The system being used is a See-Ro 488 meter/mix system the dispense gun in the picture is model 2200-250-000 dual-spool Snuf-Bak dispense valve that utilizes a No-Rush disposable static mixer nozzle. (Photo provided by Sealant Equipment and Engineering, Inc.)...

Complete and imiform dispersion of the ingredients in an adhesive or sealant is eritieal to product performance. The ehoiee of mixer, from among the many available, depends on the viscosity of the produet, any special needs (e.g. vaeuum) and how the mixed product is removed form the mixer to the filling line. Table 5 shows the viscosity of everyday items (Ross, 1989) in comparison to typical viscosities for several different types of adhesives and sealants (Flick, 1988). 

A list of mixer types used in the manufacture of adhesives and sealants is... 

Table 6. Mixers Used in Manufacture of Adhesives and Sealants ...

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