Study On Flame Retardant Properties And Test Methods Of Flame Retardant Knitted Fabric

In the case of fire,the outermost clothing that the flame first contacts.Therefore,people's research on flame retardant fabrics began with outer woven fabrics that have both strong and wear-resistant properties.A lot of research has been conducted on their flame retardant properties and material development.The existing various flame retardant test evaluation schemes are also formulated under the conditions of use and the outer fabric encounters a dangerous state of flame combustion,such as the vertical combustion method.With the increase of labor protection awareness,the level of matching of flame retardant products and the comfort of flame retardant clothing have also been paid more and more attention by users.In addition to the flame-retardant properties of the outermost clothing,the demand for flame-retardant clothing used in the middle and inner layers is also increasing.The flame-retardant knitted fabric is used as a matching underwear,middle layer or as a T-shirt,etc.,and is used in conjunction with the outer flame-retardant woven fabric,which can improve the comfort,warmth and flame-retardant function of the flame-retardant protective clothing.On the one hand,knitted fabrics and woven fabrics are significantly different in organizational structure,stress deformation,etc;on the other hand,as matching clothing,the flame retardant knitted fabrics contact the flame in a different way from the outer clothing,in the flame retardant matching series,The role played is also different from woven fabrics.Therefore,there is an urgent need to formulate corresponding assessment standards and evaluation indicators for the use characteristics of the flame retardant matching middle layer and inner layer clothing.This paper first studies the test method of flame retardant performance of flame retardant knitted fabrics.To study the impact of knitted fabrics on the flame retardant performance evaluation of knitted fabrics under the existing national standards and the general test method of the verticalcombustion method,and to evaluate the impact of various parameters and index evaluation methods on the knitted fabrics.The more appropriate and scientific test parameters of knitted fabrics include:reasonable sample size,clamping method,how to deal with curling,and determination method of carbonized length.The study found that in the early stage of sample preparation,the sample was cut along the direction of the coil,and the horizontal size of the sample was changed from 89 mm to 92~ 95 mm,which can ensure that the bottom of the sample and the bottom of the sample clip are Improve the accuracy of experimental data.In the damage length measurement stage,reducing the mass of the suspended weight during the damage length measurement and changing the weight suspension method and length measurement method have greatly improved the accuracy and repeatability of the damage length.Secondly,a comparative study of the flame retardant properties of knitted fabrics and woven fabrics under the same yarn formulation.Yarns with different flame retardant properties are used to prepare knitted fabrics and woven fabrics of the same gram weight with class A,B and C flame retardant properties,respectively.The thickness,air permeability and flame retardant performance(vertical combustion method)were compared to analyze the flame retardant performance difference of knitted fabrics and woven fabrics under the same formula.It was found that the flame retardant performance of woven fabrics with the same formula and the same gram weight is better than knitted fabrics,and the two are affected by factors such as raw materials,gram weight,and organizational structure.This also shows that it is not possible to simply use the same test methods and evaluation indicators as woven fabrics to evaluate flame-retardant knitted fabrics.Finally,the flame retardant performance of the flame-retardant knitted fabric under the wearing conditions was studied,including the flame-retardant performance changes in the wearing state,after multiple wears and after multiple deformations in different parts.Knitted fabrics are easy to deform.During use,after being subjected to stretching and other effects,the pores will become larger and the structure will obviously recover irreversibly,which may affect the flame retardant performance.To study the flame retardant knitted fabric's combustion performance under different tensile states and repeated repeated stretch recovery(different stretch times,different elongation),and to discuss the flame retardant knitted fabric's flame retardant performance changes after long-term use.It was found that in the stretched state and after repeated repeated stretching,the flame retardant performance of the knitted fabric is reduced,and the fabrics with different structures have different degrees of influence,and the fabrics with large deformation are more likely to be affected and the degree of influence increases.These studies provide basic data for the testing and evaluation of perfect flame retardant knitted fabrics.And assisted in formulating the group standard ?flame retardant protective clothingflame retardant knitted matching clothing?...