3D Knit fabrics : optimizing spacer knit fabrics for comfort and breathability in infant products

Abstract: In this study we looked into an existing textile baby stroller seat and investigated whether there can be any advantage in changing the material to a spacer fabric from perspectives such as functionality, comfort, and sustainability. The subject of 3D knitting, and advanced knitting is being researched more and more because of its versatility in producing and changing parameters of knitted high quality products, but there is a lack of studies done on comfort for children when it comes to knitted spacer fabrics and not many studies have been done on spacer fabrics used for baby seats in strollers or other types of seats for children. A reason for further development and research in the area of 3D knitting is that it could be giving products a better appearance, functionality or potential for more sustainable pro-duction which could lead to better possibilities of producing more attractive advanced textile products. This could in turn make the producer more attractive among customers as well as stand out more amongst competitors on the market. Recently there has been attention on the use of warp knitted spacer fabrics in the application of cushioning to protect against impact. Thermoregulation, compression, air permeability and good energy absorption are some characteristics of spacer fabrics which are being further investigated in this study (Gokarneshan 2015). Another reason for further investigation of spacer fabrics, and their good cushioning properties, in child products is that it was shown in a previous study that children who are transported in carriers for bicycles are exposed to more vibration compared to children who are transported in automotive rides (Rothhamel 2023). A reason for examining the possibilities of replacing polyurethane foam with spacer fabric is that PU foams generally have lower air permeability in com-bination with higher heat resistance which can lead to problems regarding comfort. (Gokarneshan 2015). Testing of different spacer fabric samples was carried out based on air permeability, burst strength, and moisture management. These tests were then evaluated to determine the optimal parameters of a spacer fabric for increased comfort and functionality in an outdoor child product. Other tests that were carried out were specific tests for child products such bite test, finger probe test, and pulling test to examine the safety of each sample. We concluded that the optimal spacer fabric should be constructed of polyester rather than cotton to have as good wicking properties as possible. The fabric should have one side of the spacer fabric that does not consist of mesh so that the requirements from the finger probe test will be fulfilled. The other side of the spacer fabric should be constructed of a mesh structure to ensure good properties of air permeability. The holes should, however, not be too big since this might be less comfortable against the skin. The mesh structure recommended for this purpose is a hexagonal mesh which results in both good permeability of both water and air flow. The fabric should also be constructed with a multifilament for the spacer yarn for safety reasons.