The Principle Of Fabric Wrinkle Prevention In Fabric Processing

　 I Textile Causes of wrinkle formation

　　1、 fibre The relationship between the recovery degree of

Wrinkle can be considered to be caused by the bending deformation of the fiber caused by external force and the complete recovery after relaxation. The recovery performance (i.e. wrinkle resistance) of the fiber from bending state has some corresponding relationship with its tensile property. The higher the recovery degree of the fiber, the better the wrinkle resistance. The crease resistance of fabric can be approximately measured by the tensile property of the fiber, that is, the crease resistance is determined by the nature of the fiber.

2. Essence of fiber bending deformation

(1) In the process of drawing, different regions of the molecules in the fiber have different deformations.

The H-bond in the region with high degree of lateral order can bear the external force together, and there is less chance of intermolecular movement, mainly elastic deformation. When the Hbond in the area with low lateral order is subjected to an external force, it is deformed by the external force successively along the direction of the external force. With different strengths, bond fracture and relative displacement of basic structural units gradually occur. In addition to conventional elastic deformation, forced high elastic deformation or plastic deformation may also occur.

(2) In the process of forced high elastic deformation or plastic deformation, new H-bonds are formed along with H-bond disassembly. After relaxation, unbroken bonds and intramolecular rotation have the effect of restoring the system to its original state. However, due to the blocking effect of new H-bonds, in addition to partial slow recovery, irrecoverable deformation (permanent deformation) is left, which is the cause of wrinkles. Generally, It can also be considered that wrinkles are caused by slow elastic deformation.

Therefore, covalent crosslinking should be introduced into cellulose macromolecules to improve the elastic properties of fibers.

　　 2、 Resinous Wrinkle prevention principle ：

As for the mechanism of resin finishing, it is difficult to give a complete explanation at present, and it is generally believed that there are two functions.

1. Sedimentation theory:

The initial shrinkage of the resin with multifunctional groups is very small particles, which can diffuse into the amorphous area of the fiber. After the resin is formed, it is deposited in the fiber, establishes hydrogen bonds with the fiber molecules, and entangles the fiber molecules with each other. As a result, the relative mobility of the molecular chains is limited, and the deformation of the fabric is improved.

2. The cross-linking theoretical resin forms covalent cross-linking with the hydroxyl groups in two cellulose molecules, connecting adjacent molecular chains, reducing the deformation that cannot be recovered immediately due to the hydrogen bond disassembly, and improving the recovery ability of the fiber from deformation.

3. Explain from the perspective of physical chemistry

Cellulose fiber mainly plays the role of internal energy in the process of drawing and recovery. The more internal energy stored, the greater the elasticity.

3、 Relationship between crosslinking degree and wrinkle resistance

1. Crosslinking degree

The higher the concentration of crosslinking agent is, the greater the degree of crosslinking is, and the better the anti wrinkle performance is. However, if the crosslinking agent is too large, the strength decreases too much.

2. Cross-linking distribution

Covalent crosslinking can only occur on the surface of amorphous and crystalline regions.

Dry crosslinking: good dry crease resistance, poor wet crease resistance (the area with high side order makes the Hbond broken).

Wet cross-linking: cross-linking occurs in the area of medium side order, and less cross-linking occurs in the area of low side order. After drying, the fiber will shrink. The cross-linking existing in the area of medium side order is in a relaxed state, while stable cross-linking is lacking in the area of low side order.