## 1 Introduction  
Mobile communications and electronic devices have become necessities for people to acquire new knowledge and communicate with others in the modern world [1; 2]. The use of electronic products such as laptops and cellphones inevitably generates electromagnetic interference (EMI) [3; 4; 5]. The electromagnetic pollution jeopardizes people's health, which leads to the presence of the EMI shielding materials [6; 7]. EMI shielding materials attenuate electromagnetic energy propagation by means of absorption and reflection, thereby refraining electromagnetic interference and pollution. The shielding materials are qualified when they have a resistivity lower than 10\({}^{2}\)\(\Omega\)/cm\({}^{2}\)[8; 9]. One simple method of shielding EMI is adopting the conductivity of metallic materials. However, the applications of metallic materials are restricted due to having a heavy weight, a high cost, and the difficulty of the process [10; 11] and conductive polymer composites (CPC) have been developed in order to address the issue [12; 13]. [PERSON] et al. studied the EMI SE of cotton/metallic composite fabrics and found that the plain weave fabrics had an optimal shielding effectiveness [14]. [PERSON] et al. investigated Cu and SS conductive fabrics, and the differences in the lamination layer and lamination angle could change the electromagnetic interference shielding effectiveness (EMI SE) of materials [15]. [PERSON] et al. compared the methods for gaining EMI SE and subsequently composed a complete shielding network with improved EMI SE [16]. The comfort of conductive fabrics compromises when the constituent metallic wires could not be unwrapped completely [17]. As a result, the conductive fabrics demonstrate oxidation corrosion, which decreases the shielding effectiveness against electromagnetic waves. Another issue is the stability of the electrical conductivity and, hence, the EMI shielding efficiency and reliability for the practice application of the CPC. In order to better solve the problem of electromagnetic radiation, it is also necessary to maintain the stability of the conductivity of the conductive material. Therefore, the shielding efficiency of the conductive material will be reliable and stable in practical applications [18; 19; 20]. For example, when conductive metal materials are used under harsh conditions such as humidity, acidity and alkalinity, the materials are easy to be oxidized or corroded, especially when the composite yarn cannot wrap the wire well [21; 22; 23]. Therefore, the conductive material is preferably corrosion resistant. In fact, a fabric having superhydrophobicity is a good candidate for achieving this goal because the superhydrophobic material can repel water droplets, thereby preventing the aqueous solution from diffusing within the conductive fabric [24; 25]. In addition to maintaining the stability of conductivity during use, the material should also have a certain flame retardant effect to prevent fires caused by electronic equipment. PSA fiber with good acid and alkali resistance has relatively better combustion resistance, heat resistant property, heat stability, and a limiting oxygen index (LOI) over 33%. However, PSA fibers have a moisture regain of 5.5%, which has a negative influence on the hydrophobicity of the resulting conductive fabrics in a moist condition [26; 27; 28; 29]. In order to develop conductive fabrics with excellent flame retardancy, excellent hydrophobicity and excellent EMI shielding properties, our laboratory has invented a feeding device for preparing conductive core-spun yarns, which is compared to conventional core-spun yarn devices. A custom-made feeding device is used to produce conductive wrapped yarns, ensuring that one or two metallic wires (i.e., the core) can be precisely wrapped in PSA roving to prevent the exposure of metallic wires.