Calendering finishing
Calendering, also known as calendering. A process of fabric finishing. The finishing process uses the physical plasticity of fibers under high pressure or high temperature conditions to flatten or roll out patterns on the surface of the fabric to enhance the luster of the fabric.
Different calendering effects can be obtained based on the roll surface material, rolling pressure, temperature, different combinations of soft and hard rolls, and cloth threading methods. Commonly used calendering equipment for garment fabric finishing in Jiangsu and Zhejiang can be summarized as mirror calender, oil calender, film calender, seven-roller calender and embossing machine.
Mirror Calender ▲
The upper roll is a metal rod with a highly polished surface. The heating roller has a nylon rod in the middle and a metal rod at the bottom, which mainly serves as a supporting rod. During production, the cloth passes between the upper roller (heating roller) and the middle roller (nylon roller). Under pressure, the heating roller and the nylon roller form a rolling point, and the cloth passes through the rolling point to achieve the calendering effect. There are also two-roller mirror calenders and controllable mid-to-high mirror calenders on the market, which are essentially the same!
The process temperature ranges from cold pressing to 160 degrees, the speed is 70 meters/min, and the pressure is 8 to 10 kilograms.
Uses: Mostly used for fabrics that require calendering to have a general luster, to improve hand feel (the handfeel will become softer and smoother after calendering), to smooth the calendered surface, and to remove sizing from dyed and finished fabrics. (The cloth surface looks like a white watermark), color change (the color will become lighter after calendering) and the previous process of coating finishing (the coating after calendering can increase the water pressure resistance of the fabric, making the rubber surface smoother, softer and smoother) It’s cool and saves glue at the same time), and rolled fabrics that are velvet-proof are also often finished with a mirror calender, such as the light and thin down jacket fabric that has been popular in recent years – 380T nylon (no gallbladder and velvet-proof).
Oil surface calender▲
Oil surface calender The difference from the mirror surface calender is that the roller under the oil surface is a rubber roller (soft roller), while the mirror surface is a nylon roller (hard roller). The working principle is basically the same!
Process temperature 160-220 degrees, 6-8 kg pressure, speed 70 meters/min
Usage: Fabric calendering finishing requires ultra-bright gloss, or slightly bright gloss For fabrics that are soft and soft, and require little color change after calendering, oil finishing is also commonly used (the color of the fabric changes greatly after mirror calendering).
Film Calender▲
There is a metal rod (heating roller) in the middle and nylon rods on the top and bottom (Imported nylon is better). During operation, the fabric passes through the lower roller and the heating roller and then passes between the heating roller and the upper roller, thus forming two rolling points, which is equivalent to the fabric being rolled twice. There are also film calenders with a metal rod in the middle and a ceramic rod on the surface. After rolling, the gloss becomes more matte and has a matte effect!
Process temperature 120-160 degrees, 8-10 kg pressure, 40 meters/min
Usage: The fabric needs to be glossy and matte, with a soft, thick and waxy feel, and a smooth skin texture. Sensitive, with film effect, such as multi-F polyester taffeta film calendering finish.
Seven-roller calender ▲
It has two heating rollers, three cotton sticks and It consists of two upper and lower metal rollers. During operation, the cloth passes between the rollers, forming five rolling points to achieve the calendering effect repeated many times. Similar to the seven-roller machine, there are five-roller calenders and six-roller machines that replace the bottom two rollers of the seven-roller machine with a nylon roller. The working principles are basically the same!
Process temperature 110-140 degrees, pressure 4-8 kg, speed 60 meters/min
Usage: mainly used for down jacket lining fabric anti-down finishing, such as the most Common 290T polyester taffeta gallbladder.
Frequently Asked Questions
Temperature, speed, and pressure are the three elements of the calender. If the post-rolling effect is not ideal, the first step is to start with this. Find reasons from three aspects.
1. The hand feels hard. If the hand feels hard after finishing, it should be considered that the temperature, pressure and speed are too high and too slow. If the hand feels hard after oiling, you can use mirror cold pressing. Of course, if the fabric is too hard before finishing If so, it is unlikely to become too soft after rolling!
2. The glossiness is too bright or too dark. Brightness is mainly determined by temperature. If it is too bright, the temperature should be lowered, the speed should be accelerated and the pressure should be reduced. If it is too dark, the opposite will be true.
3. Side difference and head-to-tail difference. When both sides are bright, the pressure should be reduced, and when the middle is bright, the pressure should be increased (the roller has a medium height); the head-to-tail difference should mean that the temperature is not consistent. Generally, the temperature is controlled at Within plus or minus 5 degrees!
4. The anti-lint effect is poor. If the anti-lint effect is not good, you should slow down the speed and increase the temperature and pressure, or increase the number of calendering times!
5. Wrinkle marks. Rolling marks are a common problem in calendering. Wrinkles on both sides should increase the tension of the fabric, and wrinkles in the middle should reduce the tension of the fabric. If there are wrinkles in the middle, you should also check whether the lower cloth rack is clean. Too much friction can easily cause scratches on the cloth surface. Generally, the distribution of processed packages should be rolled into large rolls before processing to achieve the purpose of constant tension!
6. Calendering spots Calendering spots are the mostCommon defects are caused by unclean roller surface (for example, there are threads on the roller surface). The roller surface must be wiped frequently during production! Damage to the roller surface will also produce calendering spots (such as small pits caused by the nylon rod pressing against hard objects, etc.).
The difference between calendering, electro-optical and embossing
1. Calendering finishing uses cotton fiber under wet and hot conditions. , has a certain degree of plasticity. Under a certain temperature, moisture and mechanical pressure, the yarn of the fabric is flattened, and the erected fluff is pressed on the surface of the fabric, thereby making the surface of the fabric smooth and smooth, and the degree of diffuse reflection of light reduced, thereby improving gloss.
2. The principle of electro-optical finishing is to use a rolling point composed of a heated roller and a soft roller with densely engraved parallel diagonal lines on the surface to form parallel twill lines consistent with the main yarn twist direction after rolling on the surface of the fabric. , regularly reflects light, improves the irregular arrangement of fibers in the fabric, and gives the fabric a soft, silky luster appearance.
3. Embossing finishing is to use engraved rollers to roll the fabric to produce a concave and convex pattern effect and a local gloss effect on the surface. The embossing machine consists of a hard roller (made of copper that can be heated) and a soft roller (paper meal). The hard roller is engraved with a positive pattern, and the soft roller is engraved with a negative pattern. The two match each other. . After the fabric is rolled by the embossing machine, a concave and convex pattern is produced, which plays a role in beautifying the fabric. There are currently three types of embossing finishing: embossing, copying and local gloss.
No matter whether it is calendered, electro-optical or embossed, if it is processed purely by mechanical methods, the effect will not be washable. If combined with polymer resin finishing, a durable finishing effect can be obtained. </p
