Analysis of fit pattern of a hygiene mask for an opened mouth

Abstract

A hygiene mask covers the wearer’s nose and mouth, and is intended to prevent exposure to viruses, pollen and so on. It is important to develop a mask that fits well as the user’s mouth closes and opens. How well the mask fits to the face when the user’s face shape changes, for example when speaking, was investigated. The three-dimensional (3D) coordinates of the face of a head mannequin with a wide open mouth were measured using a 3D analyzer. Following this, flat patterns with four different sizes were analyzed using a geometric triangle combination method, as was performed in a previous study. These analyzed patterns for the maximally opened mouth were confirmed to be valid using a statistical test with a draping pattern. No significant differences were detected between the analyzed pattern and draping pattern. Three-dimensional coordinates for 62 participants while they opened their mouths in different shapes were measured and then the flat patterns were analyzed. To allow for the shape variation of the face with the mouth open and to achieve good fitting performance for a larger population, a mask sheet made from knitted fabric was proposed. The extension percentage of the sheet with knitted fabric for the closed mouth was calculated for the open mouths. From the results, the necessary sizes of the mask sheet can be estimated for both the closed and opened mouth.