Study On Water And Oil Repellent Finish Of SMS Nonwovens

The safety of medical protective products has been always of great concern. In recent years, under the impact of diseases such as SARS and avian flu, it has become more focused to improve the safety performance of medical product. SMS nonwovens as a new type of nonwoven fabrics are composite products of spunbond and meltblown webs with special functions. It makes full use of the advantages and overcomes the deficiencies of both spunbond and meltblown nonwovens, and enables SMS to have the good strength, good absorption, filtration and fungal resistance. SMS products of medium thickness are mainly applied to medical products, such as surgical operation clothing, surgery packing sheet, surgery cloth cover, curtain of operating room, sterilization bandage, wound placard, medicinal plaster pastes and so on. But for ordinary SMS nonwovens, the impermeability is limited. So it does not meet the sostenut improving requirements for the safety of medical protective materials. Carrying out "Three-repellent" finish on ordinary SMS nonwovens to enhance the impermeability to alcohol, blood and oil is of great significance for the further improvement of the safety of medical protective materials.The paper analyzed the principle of water and oil repellent finish from the contact angle and critical surface tension, contrasted and analyzed several common types of current water and oil repellent finish agents. Organic Fluorine agent has a good water and oil repellent effect. The test used two types of organic fluoride agents: NUVA HPC LIQ finish agent produced by the Clariant and CO-GVARD AFR finish agent produced by the Rudolf.The paper researched the water and oil repellent finish process and the process parameters. It confirmed that the finish process is pad-bake method, and determined the range of some main process parameters such as pickup, drying temperature and time, agent concentration, curing temperature and curing time. It also obtained the optimized parameters through orthogonal experiments of water-oil repellent finish process. Several levels of three orthogonal factors (agent concentration, curing temperature and curing time) were confirmed through single factor experiments. Next, orthogonal experiments were carried out, and then the results were analyzed. The optimum results of NUVA HPC LIQ finish agent are as follows: the concentration of agent is 80g/L, the curing temperature is 140°C, and the curing time is 60s. The optimum results of CO-GVARD AFR finish agent are as follows: the concentration of agent is 80g/L, the curing temperature is 140°C, and the curing time is 180s. After testing, the water and oil repellent level reached band 8 after finishing under the optimized parameters.The performance experiments of the finished and original fabric were carried out after orthogonal experiments, including tests of tenacity, air permeability and vapour permeability. The results show a little drop in these performances of SMS nonwovens after finishing. And the extent of the drop is relative to the concentration of agent, curing temperature and curing time.In sum, the paper has researched on the water and oil repellent finish of SMS nonwovens and has obtained ideal results by optimization. After testing the performance of the finished fabrics, the results show that the water and oil repellent finish on SMS nonwovens scarcely changes the original characteristics and functions.