Functional engineering from the design of inlaid 3D knitted fabric

Abstract

The development of 3D knitted fabrics is a pivotal area of textile research due to their unique properties and diverse applications. Spacer fabrics, a type of 3D knitted fabric, have two surface layers connected by filament yarns. Their excellent air permeability and compression resilience make them a superior alternative to elastomeric materials like cellular foam, especially in cushioning, impact absorption, and insulation applications where breathability and comfort are essential. Despite these advantages, the knitting machine type constrains their properties: gauge affects loop size and density, while needle bed distance determines thickness. Thin weft-knitted spacer fabrics (under 1 cm) collapse easily under compression, offering limited energy absorption. Thicker yarns improve strength but increase stiffness, resulting in heavy, rigid fabrics unsuitable for wearable cushioning. With the support of three funding schemes – the Kinugasa Fiber Research Centre (1 April 2020 to 31 March 2021), the Kyoto Technoscience Centre (1 April 2022 to 31 March 2023), and the Hong Kong Polytechnic University (1 November 2023 to 31 October 2026) – this study explored innovative structures by integrating inlay knitting into the 3D design to modify and control the shape, as well as the physical and mechanical behaviour, of weft-knitted spacer fabrics. An extensive investigation covered fabric design from yarn selection and spacer structure modification to inlay structure design and product development for practical applications. This approach offers new insights into knitted fabric development by enabling greater variation in spacer fabric properties. It allows the creation of customized materials for various textile products, including protective clothing, intimate apparel, home textiles, and medical and compression garments. By tailoring different areas of a product to exhibit specific properties, overall performance can be significantly enhanced. Research outcomes were disseminated through journal papers, conferences, exhibitions, and invited talks, underscoring the potential of this innovative approach to transform the textile industry.