A hygiene mask covers the wearer’s nose and mouth to prevent exposure to viruses, pollen, dust, and so on. To produce the anticipated effect of wearing a mask, it is important to develop a mask with high fitting performance while closing and opening the mouth. Moreover, masks are to be used by individuals as well as many users. Therefore, flat patterns for a mask that fits a wider variety of face shapes are needed to effectively accommodate more people. As a first step, in this paper the mean flat pattern for a mask that is appropriate for a greater variety of face shapes with a closed mouth was developed. A three-dimensional (3D) motion analyzer was used with consideration of further research of facial motion. Four kinds of flat patterns of masks of different sizes for the closed mouth were analyzed and proposed. First, confirmation tests of 3D motion analysis were conducted using a basic model. Second, using the data of the basic model and a head mannequin, a geometrical analysis method for two-dimensional (2D) patterns from 3D coordinates using triangular combination was proposed. For evaluation of the analyzed pattern, draping patterns for the basic model were acquired by draping the head mannequin with nonwoven sheets, and the match between the analyzed pattern and the draping patterns was assessed. Moreover, 2D mean patterns derived from the 3D coordinates of 62 subjects were proposed. It was confirmed that the distance difference over the circumference was 0.99 mm with a standard deviation of 5.0 mm.

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.