How to dye, print and choose coating additives for nonwovens

With the rapid development of nonwoven technology and the continuous expansion of application fields, the market demand for functional nonwovens and personalized nonwoven products has further increased. At the same time, dyeing and finishing technology is playing an increasingly important role in the non-woven fabric manufacturing industry. It can be said that dyeing and finishing technology has become one of the important means to promote the upgrading of nonwoven products, increase the brand and added value, and increase the functionality. Non-woven fabric printing and dyeing technology For non-woven fabrics with loose structure and low strength, if the printing and dyeing process is used to process woven fabrics, it will not only be difficult to meet the requirements of related application fields, but also not only the process is long, the efficiency is low, and the cost is high, but also the fabric Large deformation. Therefore, non-woven fabrics are often dyed/printed with paint. Nonwoven coating dyeing process: Taking the spunlace nonwoven production line as an example, there are two main processing methods: online dyeing and offline dyeing. The on-line dyeing process includes: loose fiber, open cotton, carding, thorn, foam dyeing (adhesive, paint and other additives), drying, rolling. The advantage of foam dyeing is energy saving, but it has the disadvantage of uneven dyeing. Offline dyeing processes include: spunlace nonwovens, feed cloth, padding (adhesives, coatings and other additives), pre-drying, tentering drying or drum drying, winding. Non-woven fabric pigment printing process: If the color paste of printing, coating, adhesive, corresponding additives, water mixture also needs to add thickener to increase the viscosity, and the color paste is printed on the non-woven fabric through a roller printing machine, During the drying process, the adhesive is self-crosslinked to fix the color paste on the non-woven fabric. Still taking the spunlace nonwoven production line as an example, the online printing process includes: loose fiber, open cotton, carding, spunlace, dipping, printing (coating and additives), drying and winding. Among them, the process can be used for dipping (two dipping and two rolling) method, or foam dipping method, some factories do not have this process, this is mainly determined according to the customer's product quality requirements and application areas. The printing process mainly adopts the method of roller printing. Rotary screen printing is not suitable for printing on non-woven fabrics because the mesh is easy to block. There are also some decorative non-woven fabrics using transfer printing. Using coating and binder methods, the printing and dyeing process is short, the efficiency is high, and the cost is low, which can fully meet the requirements of related application fields. In addition, the method is simple, is suitable for various fibers, has low energy consumption, and is beneficial to environmental protection. Therefore, in addition to some special products, most non-woven fabric manufacturers use coating dyeing/printing methods. For some products with special requirements, such as ultra-black products, because paint dyeing cannot achieve the dyeing effect of'shiny black', it must be dyed with dyes. Before nonwovens are processed, loose fiber dyeing is generally used. Some factories use the method of dyeing cloth, but the production capacity is low and the cost is high. The choice of non-woven fabric dyeing, printing coatings and auxiliaries, printing and dyeing coatings. When choosing dyes/printing coatings, you must first choose coatings that meet environmental protection requirements. For example, from the chemical structure screen, the 23 kinds of harmful animal structures announced by the EU In contrast, it contains or decomposes banned substances such as aromatic amines CA. can not be used. Secondly, a coating with a larger chemical structure molecular weight should be selected. When using paints produced by different manufacturers, it is necessary to use the same adhesive under the same conditions to test that its color fastness meets the product requirements, and the paint manufacturer should also be required to provide safe data. The choice of printing and dyeing adhesives Adhesives are one of the key factors affecting the quality of coating printing and dyeing. At present, acrylic self-crosslinking adhesives are usually used for paint dyeing/printing, which has the advantages of simple production process and easy control. With the development of adhesive technology, new paint dyeing/printing adhesives continue to emerge, which greatly improves the feel, rubbing fastness, color depth and other properties of paint dyeing/printing nonwovens, and better meets product quality and Environmental requirements. For example, core-shell emulsion polymerization prepared adhesives.