An Introduction to Hook and Loop Fasteners
A hook and loop fastener, commonly known as velcro due to the Velcro brand name, is a fastener consisting of two linear fabric strips attached to the opposing surfaces to be fastened. The first layer of fabric is covered with tiny hooks, and the second is covered with tiny loops. Resins on the hook and loop fastener offer a secure connection, but one that is still easily removable. They are used in a broad range of industries such as aircraft, automotive, and industrial, as well as applications pertaining to clothing materials, supplies, and consumer products. In this blog, we will take an in-depth look at hook and loop fasteners.
There are three main types of hook and loop fasteners: standard velcro hook and loop fasteners, velcro sew-on hook and loop fasteners, and hook and loop fastener tapes. A standard velcro hook and loop fastener consists of small plastic hooks with even smaller plastic loops. Velcro sew-on hook and loop fasteners are designed to be sewn onto clothing materials and supplies. Fasteners
of this type are made from brushed polyamide and contain many tiny hairs. Hook and loop fastener tape is tape made from adhesives that rapidly attach to nonporous surfaces like cabinets and walls.
Hook and loop fasteners also vary in terms of their specifications. These include operating temperature, stretch, and width. In terms of operating temperature, speciality hook and loop fasteners can withstand temperatures up to 100º C. The strength of a Velcro hook and loop fastener
varies, often depending on the area of the surface that remains in contact with the hooks. Finally, these fasteners come in many different shapes and widths. The average tape width of a Velcro hook loop fastener is between 20 mm and 50 mm, and most rolls have a length of approximately 25 meters.
Furthermore, like any parts used in the highly-regulated industries of aerospace and aviation, there are certain standards that hook and loop fasteners must adhere to. For general hook and loop fasteners, there are standards set forth by the American National Standards Institute (ANSI). For fastener tapes
and synthetic hook and loop fasteners, there are the A-A-55126 standards upheld by the Naval Publications and Form Center (NPFC). Lastly, for pressure sensitive, adhesive coated hook and loop fasteners, there are the Delphi DX520003 standards.
The main advantages of these fasteners is that they are easy to use, safe, and relatively maintenance free. There is also only a slight decline in effectiveness even after many fastenings and un-fastenings, and the tearing noise can provide added security. However, they are not without their drawbacks. For one, hooks can commonly accumulate hair, dust, fur, and similar debris after a few months of regular use. Additionally, loops can become elongated or break after extended use. Nevertheless, hook and loop fasteners are still a very popular fastening method, and one that will not be going away any time soon.
Posted on March 8, 2021