Advanced Adhesive Bonds
Warwick is an industry leader in engineering high-strength adhesive bonds for technical textiles and fiber composites.
High-performance textile bonding must be approached with advanced knowledge of chemistry, physics, engineering, and a broad-based experience with adhesion.
In many commercial textile products, two or more textile adhesive bonding methods may be employed.
Mechanical bonding is possible when the construction of the fabric is reasonably open and sufficient adhesive is available to penetrate into the fabric. The adhesive is applied as a water- or solvent-borne material in a dipping operation. After cure, the hardened adhesive is mechanically locked to the fabric. The thickness and modulus (stiffness) of the adhesive must be carefully balanced with the fabric to create a smooth transition of stresses from one layer to the other.
Hydrogen bonding is possible only in industrial textiles with polar fibers. In this case, there is a strong electrical attraction between the adhesive and the fiber. Both polyester and aramid, for example, do not possess sites for hydrogen bonding.
Chemical (Covalent) Bonding
Chemical, or covalent, adhesive bonding occurs when there is a chemical reaction between the fiber and the adhesive. This reaction is only feasible under ideal conditions when the fiber is very clean and the adhesive is in intimate contact with the surface.
Chemical bonds are much more difficult to achieve than other bonding methods. The chemical bond is the most heat resistant of all the types of adhesion. The biggest hindrance is the residual spin finish used in fiber manufacturing, which is difficult to remove even with highly technical scouring processes.
Thermodynamic adhesive bonding is the most practical and predictable of the four theories of adhesion. During this bonding method, the adhesive swells the top layer of textile and mechanically locks into the fiber layer. Solvent welding is a simplistic example of this type of bond. This textile bonding method is the prominent mechanism for nylon, rayon, and polyester and is a useful starting point for aramid.
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