Sewability Improvement of Knitted Fabrics
When sewing knitted fabrics on industrial sewing machines for the production of T-shirts, fine knitwear, vests or cardigans, the sewing needle penetrates the knitted tricot or jersey fabrics at high speed. Ideally, the needle displaces the loops and slides through the textile fabric. If the mobility of the loop threads is not optimal, the loops remain stiff and inflexible. This way the needle may hit a loop and damage the loop threads. This can lead to small holes, so-called loop damages, and subsequently cause runs, ladders or holes.
The mobility of the thread sections or rather the deformation behavior of the loops is of considerable importance for the sewability of extremely fine knitted fabrics. Optimal, tailor-made yarn and textile finishing with appropriate textile auxiliaries, yarn lubricants and softeners improves the flexibility of loops and the sewability of knitgoods. Furthermore, the needle penetration force as well as the risk of loop damages when sewing are reduced. This significantly improves the quality, especially of super-fine ready-made knitwear.
Factors Which Influence the Sewing Process
In industrial sewing workshops knitted or warpknitted fabrics are sewn at high speeds on industrial sewing machines. The following factors have a direct influence on the sewing process:
- sewing machine
- sewing needle
- sewing thread or twist
- knitted or warpknitted fabric
Parameters with Impact on the Occurrence of Loop Damages
The direction of sewing, the goods’ moisture as well as the humidity in the sewing room have less impact on the occurrence of loop damages. However, the following parameters have a bigger effect:
- needle size
- shape of sewing needle
- number of fabric layers
- sewing thread lubrication
- textile fabric finishing
Improved Quality Through Tailor-Made Textile Finishing
We offer textile-chemical products such as sewing yarn lubricants and finishing agents which are used to minimize potential problems which could arise during sewing. Finishing of the textile fabrics with tailor-made textile auxiliaries helps to improve the quality of delicate ready-made knitwear. Textile finishing of the knitted or warpknitted fabrics with softeners improve the textiles’ handle and enable gentle processing in the sewing workshop. Yarn finishing of the sewing threads reduces friction during sewing and serves as heat protection.
Yarn Finishing of Sewing Threads with Lubricants
Sewing thread lubricants ensure that the sliding and friction properties of the sewing yarn is improved. Yarn finishing leads to lower and more even fiber/metal and fiber/fiber friction compared to non-finished threads. Well-finished yarn can be optimally processed on the sewing machine even at highest speeds. Yarn lubricants optimized for heat protection effectively dissipate the frictional heat generated by the sewing process from the needle. This prevents the threads from melting or the sewing material from being damaged by the hot needle.
In our laboratories we can measure needle temperature, friction values and stick slip values. We can offer you to run quality comparisons of sewing thread lubricants based on our test results.
Our Recommendations for Sewing Thread Lubricants
We offer different sewing thread lubricants for all kinds of fibers. We would be happy to recommend the best product from our range for your application. The yarn lubricants listed below are used for yarn finishing of sewing threads and are applied to prevent loop damages when sewing knitted goods.
PERIFIL SNA/R is an excellent lubricant which is applied by bath exhaustion for the finishing of threads made of polyester and polyamide or their blends with cellulosic fibers. The sewing thread lubricant provides these threads with very good gliding properties and effectively prevents the occurrence of stick-slip effects. The lubricant absorbs the heat from the hot needle and thus avoids damaging of thread and fabric. Due to its versatile mode of action, PERIFIL SNA/R enables finished sewing or embroidery threads to be processed trouble-free even under most difficult production conditions.
PERIXEN SLH/R is an excellent sewing thread lubricant for polyester and polyamide threads which is applied by single lub hot technique. Yarns treated with PERIXEN SLH/R show good friction values. The good gliding properties are already given at the sticking to slipping transition. This helps to avoid a stick slip effect. Finished threads can be optimally sewn even under severe conditions. The heat of the needle caused by high-speed sewing is transferred to the thread and absorbed efficiently by the layer of lubricant.
Influence of the finishing of Knitted Fabrics
Finishing of the knitted fabrics with textile auxiliaries not only ensures better sewability and thus avoids loop damages but also optimizes the fabrics’ handle and improves the textiles’ smoothness. Depending on the technical demands, we also offer products which have an influence on the dimensional stability, elasticity or hydrophilic properties of the knitted fabrics.
In our laboratories we can check the quality of the textile finishing with regard to improved sewability by measuring the needle penetration force.
Recommendation of Softeners for Finishing of Knitted Fabrics
We offer different cationic, non-ionic and multi-purpose softeners as well as special sewability-improving and softening agents for knitted fabrics of all fiber types. Our different finishing auxiliaries are suitable for padding and/or exhaust method. We recommend the following softeners for improving the gliding properties of textile fabrics. The auxiliaries are well suited for the finishing of delicate fabrics in order to avoid loop damages.
PERISOFT NVJ/R is a hydrophilic, low-foaming softener based on fatty acid amine condensates and polyethylene. It is used for improving the sewability of cellulosic knitted fabrics. PERISOFT NVJ/R provides cellulosic fibers with a soft handle, smoothness and a good volume. A finishing with PERISOFT NVJ/R improves the sewability of textiles without impairing the hydrophilic properties of the finished goods.
PERISTOFT ULT is an excellent, low-foaming, hydrophilic softener for all kinds of fibers. The softening agent is based on fatty acid amine condensates, functional silicones and polyethylene. On cotton textiles and cotton blends with synthetic fibers particularly good results can be achieved. Fabrics finished with PERISOFT ULT obtain a very soft, smooth handle. Due to special additives the product improves the sewability of knitwear.
PERISOFT VA/R is a silicone-free softener, based on a fatty acid condensation product, paraffin and polyethylene. It is used independently of the substrate to improve the sewability of knitted fabrics. Textiles finished with PERISOFT VA/R obtain a particularly soft and smooth handle and their sewability is significantly improved.
PERISOFT NPE is an additive based on polyethylene waxes and fatty alcohol polyglycol ether. Textiles of all kind of fibers finished with PERISOFT NPE have a very high surface smoothness and a pleasant handle. The product effectively improves the sewability of textile fabrics.
PERISOFT MSN is a softener based on functional silicones. Finished textiles have a very soft, pleasant, smooth handle and improved sewability. PERISOFT MSN improves the resilience and thus reduces the creasing tendency of knitgoods.