Abstract:

Objective This study aims to address critical issues in existing protective head masks, such as weak seam protection, poor fit, and discomfort caused by cutting and stitching processes. By proposing a seamlessly integrated manufacturing process utilizing four-needle bed fully-forming technology, seams are eliminated through three-dimensional integral knitting and optimize functional zoning. Targeting industrial manufacturing, outdoor extreme sports, and other scenarios requiring EN 388 Level 3-4 protection standards, a three-dimensional personalized parametric model is established of the head and neck of Asian adult males. Through the synergistic design of ultra-high molecular weight polyethylene (UHMWPE) materials and structural engineering, protective performance is enhanced while improving wear comfort, addressing the urgent demand for high-quality, advanced materials, eco-friendly processes, and personalized protective equipment.

Method Based on GB/T 2428—2024 "Adult Head and Face Dimensions" and GB/T 23461—2009 "Adult Male Head 3D Dimensions", a parametric model of the human head and neck was constructed, and the four regions of the fully formed protective head mask were optimized and analyzed, which are the head fit forming region, eye opening forming region, breathable sandwich mask region, and neck and jaw dart forming region. The head fitting area was created by adopting a parabolic curve needle closing algorithm to obtain three-dimensional wrapping through gradient density control, and the eye opening area was achieved by combining C-shaped rib knitting and dynamic control of the yarn-feeder to form a smooth skeleton structure. The breathable mask area was constructed with a breathable sandwich through partial knitting technology, and the neck and jaw dart area were formed by adopting a three-step molding to ensure the precision of curved surface fitting. Shima Seiki MACH2X153 four-needle-bed computerized flatbed knitting machine with machine number E15 was used. In order to knit smoothly on the four-needle-bed computerized flatbed knitting machine and to make the fabric more elastic, two additional polyamide ammonia-covered yarns with specifications of 5.56 tex/2.22 tex were added in addition to 66.67 tex UHMWPE yarn for knitting to achieve the one-piece forming of the head mask. In order to evaluate the feasibility of UHMWPE in the knitting of the fully formed head mask and to verify the actual protective effect, as well as to ensure the practicality of the head mask, the cut resistance, tensile recovery and air permeability of the head mask were tested according to the standards of N 388:2016+A1:2018, FZ/T 70006—2004 and GB/T 5453—1997.

Results The study demonstrated significant enhancements in the three-dimensional fit and functional performance of the head mask. In the head-fitting zone, precise control of narrowing points along a parabolic trajectory combined with a gradient narrowing process applied at longitudinal intervals was applied to successful replication of a rounded, parachute-like structure that conforms to the natural curvature of the human head. C-shaped rib knitting technology was utilized to form the eye-opening zone, with No.6 yarn feeder reciprocating across both sides of the opening to create smooth-edged openwork structures, with the width and curvature precisely matching the lateral canthus spacing and the oblique nasal-to-canthal distance. The breathable mask section was contoured through a partial knitting process that pauses on both sides while focusing on the central structure, combined with the independent operation of the needle bed and the regular movement of the yarn nozzle to complete the composite layer, thereby enhancing breathability and application potential. The neck and jaw dart were ensured through a three-step knitting process to achieve a precise three-dimensional fit in the neck and jaw area. Moreover, the introduction of UHMWPE brought the cut resistance index of the head mask to 0.99, further validating the feasibility of this material in the full-form knitting process. Test data show that the horizontal stretch recovery rate of the neck and jaw area reaches 54.27%, meeting the deformation recovery requirements during dynamic wearing. The breathability of the mask area reaches 827.9 mm/s, far exceeding the basic human respiratory requirement of 250 mm/s. These results confirm that the fully formed head mask has achieved the expected goals in terms of protective performance and practicality of wearing.

Conclusion Combining the excellent protective performance of UHMWPE and the excellent full-forming process of four-knit and four-needle bed full-forming technology, the protective head mask is realized in one piece, which significantly improves the comfort and protective performance of the head mask. The fabricated fully formed protective head masks have good cut-resistant performance, appropriate tensile recovery, and breathability to meet human respiratory needs. The application of four-needle bed full-forming technology not only solves the cutting and sewing problems of traditional head masks but also provides a new idea for the design and production of protective head masks, and the selection of raw materials in this study also provides a reference for exploring the knitting forms of UHMWPE-based protective textiles. In the future, the knitting process can be further optimized to expand its application in special protective fields.

Key words: fully formed, protective head mask, partial knitting, ultra-high molecular weight polyethylene yarn, parachute-style knitting, knitting technology