Also known as calendering. The final process of heavy leather finishing. The finishing of the fabric gloss is improved by flattening or rolling out the parallel fine lines with the plasticity of the fibers under mixed heat conditions.
Operation process
Operate with a pendulum calender or a bottom roller. Usually the operation is two times: the first time is to compact the leather body, after the tempering, and then stack the balance of water; the second time is calendering, after the calendering, the surface of the heavy leather is smooth and smooth, and the leather body is firm and compact. leather.
Calender
The calender consists of several hard and soft rolls with a smooth surface. The hard roll is a metal roll, the surface is highly polished or engraved with dense parallel slashes, often with heating means; the soft roll is a fiber roll or a polyamide plastic roll. The fiber roll is made by pressing the fiber as a raw material under high pressure. According to the fiber raw material, there are a cotton paper roll, a wool paper roll and a linen paper roll. The rolling point composed of the hard roll and the soft roll is called a hard rolling point, the rolling temperature is 60 to 70 ° C, and the water content of the fabric is preferably 5 to 10%. After the fabric is rolled, the yarn is flattened, the surface is smooth, the gloss is enhanced, and the hand feels stiff, which is called flat calendering. The rolling point composed of two soft rolls is called soft rolling point, and the rolling temperature is generally 40-60 ° C. After the rolling of the fabric, the yarn is slightly flat, the gloss is soft, and the hand feel is soft, which is called soft calendering. When using a multi-roller device, different surface glosses can be obtained by using different combinations of soft and hard nip points and changes in pressure, temperature, and threading. If the fabric is first padded with the resin shrinkage and pre-baked, a more durable gloss can be obtained after calendering.
