High-temperature and high-pressure dyeing is an important dyeing method for polyester fiber. Due to the dyeing characteristics of polyester fiber and its special method of high-temperature and high-pressure dyeing, it also has special requirements for the leveling agent used in high-temperature dyeing. The differences in the form categories of textile semi-finished products further create different special and individual requirements for high-temperature leveling agents. Therefore, in addition to the most basic properties such as slow dyeing and transfer dyeing that are suitable for high temperature conditions of 130°C, there should also be specialized varieties that are suitable for the dyeing characteristics of various types of polyester fiber semi-finished products. Otherwise, it will be difficult to apply in specific applications. It can well target the individual characteristics of various types in high-temperature and high-pressure dyeing, greatly reducing its applicability.
Different dyeing characteristics of different fiber semi-product categories
Polyester fiber Various types of textile semi-finished products also come in various forms such as loose fibers, yarns, and fabrics. Loose fiber dyeing is required for color spinning. Yarn dyeing is mainly used for yarn-dyed weaving, followed by sewing and embroidery. Fabric dyeing is required for garments, home textiles, industrial fabrics, etc. The dyeing of fabrics is also divided into various forms such as loose dip dyeing, open jig dyeing and beam dyeing. Although they all use high-temperature and high-pressure dyeing methods, different forms of fiber semi-finished products must be matched with different dyeing equipment that conforms to their respective form characteristics; otherwise, the style, characteristics, and product quality of the textiles will obviously be severely affected. damaged, or even in terms of the viability of no staining.
The loose dip dyeing machine is suitable for weft knitting, warp knitting knitted fabrics, and wool-like woven fabrics. Open-width jig dyeing is suitable for woven fabrics with no elasticity requirements, especially for thin filament-like silk woven fabrics, which are generally not suitable for this type of machine. For mesh type loose warp knitted fabrics (such as mosquito nets, etc.), a warp beam dyeing machine is suitable.
Yarns are mainly dyed in packages or caged skeins. Although loose fibers are also dyed in cages, they are quite different from caged dyeing of yarns. differences in form.
Basic functions and personalized requirements of high-temperature leveling agents
1. Basic functions of high-temperature leveling agents
Hydrophobic disperse dyes are suitable for dyeing hydrophobic polyester fibers. However, the hydrophobic nature of the dye determines its low water solubility. . This should be said to be a rather contradictory thing in the dyeing process using water as the medium. For this reason, commercial disperse dyes are blended with a large amount of surfactants such as diffusing agents in a proportion no less than that of the dye. Generally dye:filler=1:1~1.5. As an additional high-temperature leveling agent added to the dyeing working bath, it also has a certain auxiliary and supplementary role in order to promote the suspension and diffusion state of disperse dye particles in the dyeing working bath and maintain a uniform and stable distribution. This is particularly important for light and medium colors with less dye consumption, because the amount of light and medium color dyes is correspondingly less, and the diffusing agent brought in from the dye is simultaneously reduced. High-temperature leveling agents are necessary. Provide some compensation.
The leveling of dyeing requires ideal retarding function, which is the key function that all leveling agents must have. However, level dyeing of polyester fibers with disperse dyes must be combined with a strong dye migration function, because there is no chemical reaction from the beginning to the end of the dyeing of polyester fibers with disperse dyes; and the tight structure of polyester fibers and their extremely dense Characteristics such as the surface crystal layer play a key blocking role, and dye migration can make up for the gap in slow dyeing. Especially after reaching the 130°C insulation dyeing stage, most of the dye in the dye bath has been When the dye is applied to the fiber, the retarder function has basically completed its mission. The dye transfer function has become the main role at this stage. It will further promote and ensure the overall target effect of the leveling agent.
So, retarding dyeing, dyeing transfer and diffusion aid are combined to form the most fundamental elements of high-temperature leveling agent, and they are also suitable for use in various types of dyeing machines. Must-have basic functions.
2. Analysis and classification of personalized requirements
Different dyeing The different dyeing operation modes of the machine also produce personalized and special requirements for high-temperature leveling agents. In addition to the above basic necessary functions, it is also necessary to form a series of personalized and differentiated varieties such as low-foaming type, anti-sedimentation type, penetration-enhanced type, etc.
①Low foam type and its applicability
For nozzle types such as liquid flow and jet In the loose-type fabric exhaust dyeing machine, because the fabric runs rapidly in the liquid flow, jet and other dyeing machines, the dye bath is violently agitated. Especially in semi-filled dyeing machines, certain auxiliaries and dyes are prone to foaming under these environmental conditions. Leveling agents containing adducts of ethylene oxide are more likely to foam. If the foam continues to increase and reaches a certain level, the nozzle will form foamy air suction, causing the spray pressure to drop, eventually causing the gray fabric to stop passing. Once it stalls, it is very likely to produce color flowers, and wrinkle marks often occur. The longer the stall time, the more serious the consequences will be.
For this reason, the high-temperature leveling agent used in this type of dyeing machine should be low-foaming. Of course, from a subjective perspective, it is best to be bubble-free, but this is not in line with objective reality. The vigorous stirring effect of this type of dyeing machine from beginning to end during operation is essential for fully maintaining the dyeing bath.It is very beneficial to solve the good suspension state of dyes, but on the other hand, it is the power source that constantly causes foam. It is unrealistic and impossible to require complete foam-free operation. Therefore, in semi-filled liquid flow and jet dyeing machines, it is still very necessary to use defoaming agents.
But it should be mentioned that in a fully filled jet dyeing machine, there is almost no need for foam. Another type of overflow dyeing machine, because the dyeing operation of gray fabrics is driven by the unpressurized gravity flow of water and does not have a nozzle, so there is no need to add an additional defoaming agent.
②Anti-sedimentation type and its applicability
For high temperature and high pressure In jigger dyeing machine, the operation of gray fabric is mechanical transmission, and the amount of foam does not have much influence on the dyeing operation and dyeing effect. However, the operating characteristics of this type of dyeing machine are that it transfers cloth but not water, and the small bath ratio makes the dye g/l unit concentration of the same color formula in the dye bath much greater than that of liquid flow, jet type, bobbin, and loose fiber. Class dyeing machine (generally at least doubled).
These have correspondingly increased the objective conditions for the aggregation and precipitation of suspended dyes in the dye bath, so the probability of color spot defects is much greater than that of strong configuration. Circulation pump type of dyeing machine. Therefore, they especially need to adopt enhanced diffusion and anti-sedimentation functional types to be more suitable.
③Penetration-enhanced type and its applicability
Bobbins and cages Equipment such as skein loading and loose fiber dyeing machines are also equipped with powerful circulation pumps. However, they are different from liquid jet dyeing machines in that the fibers are fully immersed in the dyeing working bath and are not Using a nozzle, foam problems and anti-sedimentation requirements are not very acute.
However, they are different from the characteristics of the jigger dyeing machine in which water moves and the fiber does not move, and is far better than the single-layer dyeing machine such as liquid flow machine, jet machine, jigger dyeing machine, etc. For gray fabrics, which are much thicker fiber stacks in the dyeing operation mode, including beam dyeing machines, in addition to mechanical equipment requiring sufficient water penetration capabilities, high-temperature leveling agents can supplement and strengthen the inner, middle and The good permeability of all outer fiber layers is both important and necessary for the leveling of this type of dyeing machine. Therefore, for them, it is appropriate to use a penetration-enhanced high-temperature leveling agent.
Editor’s Note
Level dyeing is the main quality goal of dyeing One, therefore, the leveling agent plays a very important role in dyeing. The high-temperature and high-pressure dyeing of polyester fiber has diversified the varieties of textile semi-finished products and the selectivity of dyeing equipment, which also brings about the diversity of functional requirements for high-temperature leveling agents. Therefore, the design and development of high-temperature leveling agents are inevitable and necessary in terms of variety series and specificity, so that they can well meet the actual needs of various types of production in high-temperature and high-pressure dyeing.
However, it must also be noted that leveling agent is not the only factor that determines leveling. Factors that affect leveling include the selection of specific dye varieties (compatibility), heating rate, vehicle blocking operation, and the status of the equipment. Only by reliably controlling all influencing factors can the leveling of dyeing be highly and stably reflected. </p
