The effect of heat treatment on the performance properties of double knitted fabrics

The knitwear industry is one of the most promising industries in the world that achieved development by invading global markets. Currently, it is the second most common textile industries in Egypt due to its low production costs, leading to lower value compared to the woven fabrics in addition to the speed of production and ease of use.
In the second half of the twentieth century, the knitwear constructivist compositions have witnessed a remarkable development, resulting in new trends and the diversity of forms of artistic values and Constructivism on the surface of the product. The rises and dips in the surface of the fabric are considered the most prominent manifestations of structural formulations for knitted products which play a key role in achieving professional and technical dimensions in the design process.
The three-dimensional Weft knitted fabrics is a new area of the knitted fabrics development that can be produced on knitting machines through making it as two separate layers of cloth to connect them to each other through a number of separate strands spaced between the two classes in the level of orthogonal by an angle of 90 degrees easily separated into two layers depending on the end-use.
The rise and fall in the surface is made by many various techniques, including the use of acrylic yarns mixed with Lycra and making thermal processors of cloth by exposing the output cloth to water vapor for a certain period which will affect the places of Lycra yarn and leads to shrinking while the content section on acrylic yarns remain without shrinking. Then, the process of cooling begins to remove heat from the impact of exposure to steam and the cloth retains its shape.
A field study noted the absence of specific time of heat treatment and that it differs depending on place or personal experience without relying on science, causing a difference in the cloth output performance and the properties of its dimensions that increase the cost and reduce the competitiveness of the final product.
So, measuring the impact of the different time of processing vaporization heat of double knitted fabrics on the properties of the cloth output was the research goal.
In this research, three kinds of designs of double knitted fabric have been produced so that the proportion of the cohesion of the two layers of fabric together differs (thick - medium - mild) at flat Knitting Machine Guag 7 using acrylic yarns 28/2 and strings Acrylic / Lycra 14/1 and a heat treatment on the cloth output has been done with different time " 3, 7 and 13 second" with a sample without heat treatment and then measuring some properties of cloth output which is the number of rows and columns in the unit of measurement, thickness, weight per square meter, thermal insulation, air permeability, water vapor absorption