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How to ensure the embossing quality of spunlace nonwovens? Factors affecting the embossing style of spunlace nonwovens
- 2024-09-27
Spunlace nonwovens have many advantages such as high strength, low fuzzing, good air permeability, and soft feel. They have been increasingly popular with consumers in recent years. As the largest category, embossed spunlace nonwovens have a variety of nonwoven surface styles, such as honeycomb embossed wood pulp spunlace nonwovens, small pearl embossed spunlace nonwovens, dot embossed spunlace nonwovens, cloud embossed spunlace nonwovens, diamond embossed spunlace nonwovens and Crepe embossed wood pulp polyester spunlace nonwovens. They have the advantages of beautiful fabric, strong cleaning power and good feel.
Among them, the general requirements of customers for the surface style of embossed spunlace nonwovens are clear texture, strong three-dimensional sense, full particles, and not too much bottom exposure.
In order to provide customers with embossed spunlace nonwovens that meet the needs of use, performance and aesthetics, Soonercleaning also has many factors that affect the style of spunlace nonwoven fabrics. This article takes the Soonercleaning semi-cross spunlace production line as an example. The following will analyze the main influencing factors such as the cylinder, working roller and doffer speed, spunlace winding mode, carding machine output fiber ratio, each section drafting force, spunlace pressure, and jacquard water needle plate usage.
1. Cylinder, working roller and doffer speed
Soonercleaning adjusts the cylinder speed according to the raw material. For polyester raw materials, the cylinder speed should be set higher, and viscose is relatively low. When the cylinder speed remains unchanged, the higher the working roller speed, the more fibers are transferred and supplemented, and the better the uniform mixing effect, but the combing ability decreases, and cloud spots and cotton knots are prone to appear on the mesh surface. On the contrary, if the working roller speed is reduced, the combing ability is enhanced.
For low-weight spunlace nonwovens, due to the small amount of fibers, a slight unevenness will easily cause holes, so the working roller speed should be adjusted appropriately to allow more fibers to participate in transfer and coagulation to ensure uniform mesh surface; for high-weight products or in high-speed production, more attention should be paid to strengthening the combing effect to ensure that the fiber web is clear and has fewer cotton knots.
When the cylinder speed is constant, the faster the doffer speed, the higher the fiber transfer rate and the higher the output.
In actual production, the speeds of the doffer and the cylinder need to cooperate with each other. If the doffer speed is too low, the fibers on the cylinder cannot be transferred to the doffer in time for repeated combing, which will form small cotton knots; if the cylinder speed is too low, the combing is not sufficient, and cloud spots will form on the mesh surface; if the cylinder speed is too fast, it is easy to over-comb and break the fibers, which is manifested as an increase in short fibers on the mesh surface and a decrease in the strength of the finished cloth. Therefore, in actual production, the quality of the fiber web and the finished cloth should be carefully observed, and the speeds of the cylinder, fiber working roller and doffer should be adjusted comprehensively to achieve the best quality of the fiber web and the cloth surface.
2. Spunlace wrapping mode
Spunlace production has two wrapping modes. Generally, the fiber net of plain spunlace nonwoven fabric has the same number of punctures on the front and back sides, and the entanglement effect is better. The plain products produced are tighter and stronger; while the jacquard product has a clearer pattern and a stronger three-dimensional sense. The jacquard surface of spunlace nonwoven fabric is a straight-laid surface. The fibers on this surface are messy and the number of spunlace passes is small. Its entanglement degree is lower than that of the cross-laid surface, but it is also easier to jacquard. The jacquard product particles are fuller and can also achieve a higher thickness.
3. The proportion of fiber output by the carding machine
The jacquard surface of the nonwoven fabric corresponds to the fiber layer output by the straight-laid carding machine. Therefore, on the premise of meeting customer needs in the horizontal direction, the proportion of fibers output by the straight-laid carding machine can be appropriately increased, that is, the amount of fibers on the jacquard surface can be increased, which helps to increase the thickness of the spunlace nonwoven fabric, enhance the convex and concave feeling of the fabric surface, and make the finished fabric more three-dimensional and beautiful.
4. Drafting force of each section
High yield and high quality are important conditions for improving the profit and competitiveness of spunlace nonwoven products. Based on this, the speed of the whole line must be high. Increasing the drafting coefficient of the spunlace process and the subsequent process will not increase the speed of the whole line much, and will also greatly affect the quality of the finished fabric. Therefore, to increase the speed of the whole line, it is mainly necessary to increase the drafting coefficient of the fiber web when it passes through the cross-laying carding machine, the web laying machine and the drafting machine. Because the cross-laying carding needs to lay multiple layers of webs, the fiber layer itself is thin and has a low gram weight, so it is easy to be uneven. After being stretched by the web laying machine and the drafting machine, the quality of the fiber web will further deteriorate.
The speed of the straight laying machine can be controlled by adjusting the drafting ratio of the straight laying vertical curtain and the long curtain. The straight-laid fiber web corresponds to the side of the spunlace jacquard. In order to improve the jacquard effect, the draft of the straight-laid combed fiber web should not be too large. The draft ratio between the straight-laid vertical curtain and the long curtain can be appropriately reduced, but the draft in this area cannot be too small, otherwise the cloth surface will form continuous small horizontal stripes after spunlace. The draft should be adjusted appropriately according to the cloth surface effect during production. In order not to destroy the jacquard effect, the draft of spunlace and subsequent processes should be as small as possible without affecting production and product indicators, so that the embossing effect of the spunlace nonwoven fabric is more beautiful.
5. Spunlace pressure
Spunlace pressure has a great influence on the style of the embossed fabric surface of spunlace nonwoven fabrics. Its production water pressure follows the principle of increasing step by step. The pressure of the spunlace head in the front middle area and the first two drums should not be too large, but it should not be too small, otherwise it will cause serious fluffing of the finished fabric. The water pressure of the final jacquard drum can be appropriately increased, but at the same time, the fabric surface needs to be observed to ensure the jacquard effect while avoiding too much bottom exposure.
In addition, the spunlace pressure should also be adjusted appropriately according to the speed change. As the speed increases, the water pressure should also increase overall. The production of high-weight pearl pattern nonwovens is not difficult, and the jacquard effect is good. However, when producing low-weight pearl pattern nonwovens, it is necessary to pay attention to increasing the fiber volume and disorder of the spunlace jacquard surface by increasing the fiber web proportion of the direct-laid carding machine, reducing the draft of the direct-laid fiber web, and increasing the condensation ratio of the doffer and the condensation roller (or the chaotic roller). Otherwise, it is difficult to achieve the ideal jacquard effect by adjusting the spunlace pressure alone.
6. Usage of jacquard water needle plate
The spunlace machine on the spunlace nonwoven production line mostly adopts the production process of single-row plus double-row drainage needle plate. On the two spunlace heads of the jacquard drum, two types of needle plates are generally used, with denser water needles and larger water flow, which is convenient for jacquard. There are two processing methods. The first method produces nonwoven fabrics with a strong three-dimensional sense and clearer texture, but the fabric surface will have a large irregular bottom exposure; the other method produces nonwoven fabrics without large bottom exposure, full particles, and a stronger sense of concave and convex, but there are more regular small pinholes, and the vertical lines of the entire fabric are obvious, which affects the clarity of the pearl pattern and the three-dimensional sense of the fabric. Both methods have their own advantages and disadvantages, and can be selected according to customer needs in actual production.
