Preparation Of Maleic Anhydride Modified Starch Slurry And Application Of It In Cold Sizing On Ramie Yarn

As a cellulose fiber,ramie fiber has been widely used in daily life for its excellent performance.But because there are a lot of hairiness on the surface of ramie fiber,these hairiness will entanglement and then become an knot in the weaving process,and the shedding is not clear,which will result in reduced efficiency of loom,surface roughness,more defects in the product and so on.Then the quality of ramie products decreased,and the use of ramie textile was seriously affected.So the hairiness on the surface of the ramie yarn should be to reduce,for the purpose of expanding the application of ramie yarn in daily life.Currently,the sizing technology is the key process to reduce the yarn's hairiness.In the sizing process of yarn,we generally use the traditional sizing technology which is in hot temperature,but it has many problems such as large consumption of energy,many regenerated hairiness of sizing yarn,high breakage rate of yarn,high temperature and humidity in the workshop,which make the sizing cost high,and make the sizing quality poor.So this topic adopted the cold sizing technology in ramie yarn sizing.Cold sizing is a kind of non-traditional sizing technology,only used in a few plied yarn of wool before,the slurry is a kind of oil agent material,not starch polymer material which is commonly used in the slurry,it is the preparation of warp technology,that the yarn come through the solution at room temperature for sizing.Compared with the traditional hot sizing,cold sizing can sizing the yarn at room temperature,do not need the high temperature and long time mixing,the operation is convenient and it can reduce a lot of energy consumption.Therefore,according to the properties of ramie yarn,the modified starch which was suitable for cold sizing was researched,and the modified starch paste in special yarn was developed,which was to improve the sizing quality and reduce the production cost,it not only has importance in practical value,but also is a problem which must be solved in the current sizing production.To this,a new type of maleic anhydride modified starch slurry was developed in this topic.And the maleic anhydride modified starch with different degree of substitution was prepared by changing the dosage of maleic anhydride.The effects of substitution degree on the solubility in cold water,uniformity of film,uniformity of size and stability of size was researched,and then the slurry properties were examined.The result shows that: the substitution degree of modified starch increased gradually with the increase of the amount of maleic anhydride.When the degree of substitution is 0.373,the serous uniformity,homogeneity and stability of the slurry is the best after maleic anhydride modified starch slurry was dissolved in cold water,and the sizing performance has also been improved to some extent.Because the sizing performance of pure maleic anhydride modified starch is not very good,the maleic anhydride modified starch must be used with other adhesive in the actual production which used in ramie yarn sizing.Under the principle of no PVA in the slurry,and to improve the recurrent and penetration of the size on ramie yarn,the topic which was based on the adhesion theories,use the maleic anhydride modified starch that was matched with acrylic acid copolymer size for ramie yarn sizing.In order to select the optimal sizing formula,different formulations of slurry are prepared by changing the ratio of maleic anhydride modified starch in slurry formulation in this topic.And 10 kinds of cold sizing sizing agent is designed,then the slurry properties of each formulation as well as the sizing performance of ramie yarn are examined,which are compared with 2 kinds of the commonly formulation in the factory.Through the analysis of the slurry performance indexes of 12 kinds of sizing agent,it was found that the 11 kinds of sizing agent in cold sizing can mixing under the temperature of 25?,and this can completed without boiling,that is to say the sizing agent can dissolve in aqueous solution at room temperature.The slurry performance of 10# is the best and has reached the slurry performance of 12# which is the commonly formulation in the factory.And it was concluded that the recipe slurry have leftover slurry recycle through the test of 10# formula slurry viscosity within 3h before and after 24 h.The indicators of sizing properties of 12 kinds of slurry formulations were comparatively analyzed,it was concluded that the sizing performance of the 10# slurry formulation(concentration of 3.5%,maleic anhydride modified starch: acrylic copolymer paste=6: 4)is the best.The sizing quality indicators of it are: increasing strength rate 39.34%,reducing elongation rate 15%,hairiness reducing rate99.6%,wear-resisting number 22 count,and the sizing performance index was better than the 12# high temperature sizing formula commonly used in factory,which showed that maleic anhydride modified starch can be used in cold sizing on ramie yarn.It was found that the coating and permeability of 10# formula on ramie yarn is best,which can observed the surface morphology of the sizing ramie yarn before and after the friction through the SEM.