Using the Landau-Levich law to seal seams in waterproof clothing

Abstract

In high performance waterproof clothing, seam tape and welds fail before other parts of the garment. This paper examines a method of sealing seams in which the needle waterproofs the holes it creates by sealing them with a film of a thickness governed by the Landau-Levich law. The equation governing Landau-Levich behavior is combined with equations describing hole geometry to develop a phase space describing the fluidic and geometric properties necessary to seal a hole. A manual proof of concept test is performed which demonstrates that the basic method works. The needle speed of a standard sewing machine is then measured as is the size of the hole made by a standard sewing machine needle. These values are then used to calculate the viscosity of a fluid that will satisfy the conditions described by the phase space. An adhesive with the calculated viscosity is made and is used on a test bed to seal holes made by a needle. Each individual hole is sealed and further tests show that the seals are waterproof. Both the proof of concept and test bed experiments confirm the theory and it is concluded that needle speed, film length, and viscosity are the variables that can be controlled to tune hole sealing.