The Effect of Double Areas in Weft Knitting Fabrics on some Natural and Mechanical Properties

     The multi-layered fabrics (with a double structural composition) are characterized by durability and their ability to heat insulation, absorb sound, block out light and drip resulting from the effect of weight in This kind of fabric.
     Lycra has the advantage of improving the properties of the fabrics it contains, as it gives it high elasticity. It can be installed inside the woven with any other material, and it does not change the aesthetic appearance or the tactile feeling of the fabric.
     Rectangular weft knitting jacquard machines, Gouge: (5, 7, 12) were used to produce (3) designs of double weft knitting fabrics with two layers (3) different effects of the cohesion areas between the two layers of the fabric (1 needle / 2 needles / 3 needles) using a material: (Acrylic / Lycra) The research has reached, Then a number of physical and mechanical tests were carried out on them: (number of columns and rows, thickness, weight, thermal insulation, air permeability, bursting, water vapor absorption) to assess performance and quality according to the standard specifications.
The research found:
• There is an inverse relationship between cohesion areas and (bursting resistance, insulation, and gouge).
• There is a direct relationship between areas of cohesion and air permeability.
• There is an inverse relationship between the gouge and insulation resistance, insulation, weight, and water vapor absorption).
• There is an inverse relationship between the gouge and (air permeability, number of columns, number of rows).