I believe that everyone has encountered many problems when doing textile silicone softening and finishing, such as yellowing, fluorescence degradation, temperature problems, etc. Often some printing and dyeing factories will ignore it due to various reasons such as cost. So how to solve these problems cannot be ignored. What about the problem? The editor has compiled solutions to the more common problems for you, as follows:
01. Alkaline problem
Cotton fabrics are usually pre-treated with a higher concentration of alkali to remove fabric impurities (especially mercerizing alkali, which uses a larger amount). The alkali enters the interior of the fiber and is not easy to clean. Alkali must also be added during dyeing (reactive vat dyes), so in The cloth surface may become alkaline during finishing. Chemical fiber fabrics must be restored and cleaned after dyeing. Currently, printing and dyeing factories still use insurance powder and caustic soda for cleaning. If the subsequent cleaning is not clean, it will also cause the soft front fabric to be stained with alkali. Ordinary silicone oil is not resistant to alkali and will break emulsification under alkaline conditions. This is the reason why the factory will stick to the roll after several kilometers of padding. Therefore, before softening, the cloth surface must be washed with alkali or acetic acid added to the working fluid to keep the rolling groove pH 5-6.
02. Cohesion problem
On fabrics containing short fibers (cotton, T/R cloth, velvet), some short fibers will inevitably fall off during the processing. The short fibers falling off the fabric accumulate in the rolling groove, which is different from ordinary The silicone oil agglomerates, and as the finishing fluid moves up to the roller, it sticks to the extruded and demulsified silicone oil, forming sticky rollers or silicon spots. When the water quality is relatively poor, it will also condense with ordinary silicone oil to produce sticky rollers. In addition, similar situations will also occur with velvet fabrics. Do a good job of cleaning before driving, and clean them at any time if you find any lint.
03. Charge stability problem
Most of the dyes and whitening agents used in cotton are anionic, and cotton whitening is basically done on the setting machine. In addition, dyed fabrics need fine-tuning and color correction when the shade is wrong. Color correction usually involves adding a small amount of dye or paint when applying a softening agent. Factories generally use ordinary silicone oil (weak cations), which will produce negative and positive charge attraction reactions, causing agglomeration and sticky rollers. , and the softness of the anionic silicone oil did not meet the requirements, causing confusion in the factory. Charge consistency must be considered during processing.
04. Temperature problem
The cloth dyed by the long cotton machine must be dried in a drying drum and packed in large rolls or piled in cloth boxes. If it is not sufficiently cooled, especially the cloth in large rolls, the surface temperature of the fabric may be high when it is soft. As a result, the temperature of the rolling groove working fluid rises (especially in summer), sometimes reaching more than 60°C. When ordinary silicone oil has poor heat resistance, it can also cause roller sticking. It is better that the temperature in the rolling groove does not exceed 40 ℃.
05. Fixed speed problem
When the factory is making some thin fabrics, the setting speed is very fast, sometimes reaching a speed of 60 meters/minute. Due to the poor permeability of ordinary silicone oil, the silicone oil flows back on the roller, causing the roller to stick. Pay attention to changing the working fluid in the rolling groove and wiping the roll frequently.
06. The problem of staining the cylinder
When many factories are doing impregnation and softening, ordinary silicone oil will stain the cylinder wall. Over time, some black oil spots will form on the cylinder wall, and silicone oil spots will form on the cloth surface. Increase cleaning efforts
07. Feeling problem
As the demand for the feel of fabrics in the market is getting higher and higher, and various fabrics need to show various style requirements due to different seasons and different customer requirements, some require smooth drape, slippery and flexible, Fluffy and soft, simply elastic and so on. A kind of silicone oil can generally only reflect one style. Therefore, many factories have to use many kinds of silicone oil, causing production confusion. Sometimes they cannot find the silicone oil that suits the customer's requirements, so they have to give up business and cause losses. We can synthesize amino silicone oils with different ammonia values, viscosity and reactions to meet the softness, smoothness and elasticity requirements of various fibers by selecting amino silicone oil end groups with different ammonia values to control the molecular weight and molecular distribution.
08. Cost issue
At present, the biggest problem that puzzles printing and dyeing factories is the cost issue. Since the prices of water, electricity, and gas are constantly rising, while the printing and dyeing processing fees are decreasing, many printing and dyeing factories have been busy for a year, but there is basically no profit. Therefore, cost control is the key to printing and dyeing. The problem that the factory needs to solve. The cost of finishing auxiliaries is a big part of the printing and dyeing factory, so reducing the cost of finishing auxiliaries is an urgent problem that printing and dyeing factories need to solve.
09. Yellowing problem
Hot yellowing:
A long downtime during operation causes the fabric to remain and turn yellow, and the amino hydrogen of the aminosilicone oil is easily oxidized by air to form a chromophore, which causes yellowing. The product turns brown and the brown color makes the white fabric look like it has lost its essential whiteness or has simply turned yellow. The pH is too high and the temperature during drying is too high, causing the cotton fabric to turn yellow. Strengthen process control. Storage will turn yellow. Caused by polluting gases during storage.
10. Fluorescence degradation
The interaction between anionic whitener/cationic softener ions causes agglomeration and should be divided into two processes.
Greenish: The whitening agent is acid-sensitive or there is too much whitening agent. You should choose an acid-resistant fluorescent whitening agent.
Light damage: The light fastness of fluorescent whitening agents is poor, and the light effect causes the fabric to turn brown. Therefore, choose the fluorescent whitening agent reasonably.
Impact on water quality: The content of impurities such as microorganisms and seaweed is too high and can be filtered and precipitated to remove impurities.
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https://www.siliconefoam.net/product-hydroxyl-silicone-oil-for-fumed-silica-iota-1203d-.html
