Solvent bonding is a sealing process through which multiple pieces of material are bonded using a strong solvent. The solvent used to bond the materials together works by temporarily softening and dissolving the material. The surface molecules of the materials mix together while simultaneously dissolving, and the surfaces form a permanent seal as the solvent evaporates.
There are many uses for solvent bonding in product fabrication, including the sealing of fill and vent tubes to airtight products and other applications that won’t benefit as much from RF welding or rotary press heat sealing.
Products Fabricated with Solvent Bonding
Certain materials and shapes won’t work well with heat sealing or RF welding, which is where solvent binding serves as a useful alternative. Many different industries often require this sealing service in the construction of their products, such as:
- Inserting tubes that are fitted for inflatable airtight or watertight products
- Combining sheets of dissimilar materials to seal multiple compositions and thicknesses
Material combinations that benefit from solvent binding include Hypalon to polyurethane and PVC to polyurethane, along with natural and synthetic rubbers.
How the Process Works in Tube Fitting
In the insertion of air tubes in inflatable products, solvent binding is a vital sealing process. For instance, the military often uses products with polyurethane coated fabrics that work well with this process.
Another example of a product using solvent bonding is a containment bag, which requires an inlet for air intake. In order to accommodate this inlet, solvent bonding is an option that can be used to securely attach a polyurethane tube to the air fitting on the bag’s surface. During the process, cyclohexanone or another type of solvent coats the tubing and temporarily dissolves the material on the tube’s surface. While the material is dissolved, the tube is securely placed in the polyurethane fitting, and the solvent on the tube subsequently dissolves the material in the fitting. The materials mix together in the fitting, and once the solvent completely evaporates, a permanent seal forms between both the fitting and the tube.
Solvent Binding in Sealing Flat Plastic Sheets
Many containment applications require sheets of chemically resistant polyurethane or acrylic coated fabric to fuse with PVC coated fabric sheets. Radio frequency welding doesn’t work with polyurethane or acrylic coated materials, which means that solvent bonding is a better process to use in order to seal the edges of the materials. Like with tube fitting, the solvent is applied to both the material surfaces as they are pressed together. Hot air aids the pressure in forming the bond at a faster rate, melting the materials as they dissolve and mix.
If you’re considering solvent bonding for fabricating your products, SealWerks can help figure out if it’s the right sealing process for you.
