Today, we'll discuss the methods used by manufacturers of specialty footwear to attach soles to the upper. We'll discuss each method separately.
Welt-and-Glue:
This method is considered one of the most durable. The lower part of the sole is made of two elements: the inner sole is a rubber or leather lining, which is stitched to the welt, and the outer rubber part is glued to this element. The use of a nylon stitch in this technology eliminates the gap between the joints, ensuring all elements fit tightly together. The lower part of the sole is made of a wear-resistant, microporous material.
Glued-and-Stitched:
Using the glue-and-stitched method, the sole is attached to the edging of the workpiece using glue. The sides of the sole are then stitched on a two-thread stitching machine with a special, durable lavsan thread. This method provides additional security and prevents the seam from unraveling. Leather punctures are sealed with knotted threads and additionally treated with shoe wax to prevent moisture from penetrating the shoe.
Hot vulcanization:
This method creates a strong, monolithic bond between the rubber sole and the upper. A raw rubber compound is formed in a special mold that matches the contour and profile of the sole. The molded sole is vulcanized and attached to a preform, which is then tightened onto the insole. Vulcanization occurs at the appropriate temperature and under pressure.
Adhesive: The
adhesive method consists of several stages. First, the surfaces of the materials undergo a process of preparation for adhesive application, which requires a rough surface. Once the desired result is achieved, the adhesive is applied, after which the product is dried.
Injection
molding: The sole and upper are bonded using the adhesive properties of polyurethane. This method allows the product to be highly resistant to moisture and aggressive environments. Furthermore, the shoe becomes lighter and more flexible, increasing wearer comfort. This method is typically used for officer footwear.
the
stitch-molding method is considered the most reliable. This method is characterized as highly productive and labor-efficient, making it popular in the production of footwear with a stable range. The stitch-molding method is the same as the injection-molded method, but uses a soft, set-in insole.
Chances are, some of these methods are common to your pair of shoes, both regular and special-purpose. Learn more about special-purpose footwear on our website!