An adhesive composition containing vapor corrosion inhibitors and method of manufacturing such an adhesive is discussed in the paper. One improvement results from inclusion in the adhesive mixture of a titanium and/or zirconium containing coupling agent, either separately or as part of the VCI particles. As a result, the adhesive mixture has better uniformity and superior viscosity properties along with improved corrosion inhibiting properties during use.
Vapor corrosion inhibitors (VCI) are typically integrated into films, tapes, paper or other carrier medium. Adding VCIs into hot melt adhesives started in the late 1990s as they were introduced to protective packaging.1 In the early years of this application, the adhesive and corrosion inhibitor mixture took place in an ordinary batch process that took too much time at elevated temperatures. Due to high temperature processing, excess amount of VCI’s were used in order to make sure the end product had sufficient amount of VCI.
There were multiple goals to achieve with this research. Main goal was to lower the processing temperature, processing time, and create a homogenous adhesive and VCI mixture. Lower temperatures help conserve VCI chemistry for the final application as they tend to vaporize at a faster rate when the temperatures rise. Another goal was to achieve a higher percentage of VCI loading on the base adhesive without losing the process ability of the adhesive due to high viscosity levels.F
As for the application of the adhesive to its final state - a protective packaging fabric in this case - was to make sure the adhesive would flow properly through a hot melt application system by having a low enough viscosity, allowing the process to run at a lower temperature.
In order to overcome the processing techniques a continuous extrusion method was selected along with use of Titanate and Zirconate coupling agents to achieve lower viscosity at lower temperatures. The process of experiments is detailed on the next section. The experiments presented in this paper took place over several years and the data shown in the results may represent different production lots, however, the data belongs to same formulation and adhesive compounding method described in the experimental procedure.