Effect Of Dyeing And Finishing Process On Flame Retardant Finishing Of Knitted Fabrics

The effects of bleaching, dyeing and some chemical auxiliaries such as bleaching and dyeing on the flammability finishing of fabrics were studied.

The flammability level of fabric was tested by BS 5438 combustion performance vertical test. The test results of the method were very close to the actual combustion behavior of the fabric.

The SPSS program is used to analyze and evaluate the test results, which accurately describes how and how chemical parameters affect the combustion behavior of knitted fabrics.

According to statistics, in the general family fires, the first thing to be ignited is usually textiles, wood products and paper, etc., accounting for 63% of the cause of fire and 70% of the burning materials.

Textiles are the most easily combustible. They are usually first ignited by cotton fabrics (90.6%), followed by furniture fillers and mattresses (6%), decorative fabrics (1.7%) and other decorative textiles (1.7%).

By adopting materials with poor combustion performance, strengthening the detection of raw materials and finished products, and perfecting relevant laws and regulations, all measures can help to reduce property losses and casualty accidents caused by textiles. However, these schemes either restrict people's choices and aesthetic standards, or cause heavy financial burden to people, so they are difficult for the masses to accept.

In this way, it is very important to make clear how the fiber and fabric structure affect the final combustion performance of the product.

By controlling the process, it is possible for us to produce the final product with suitable physical and combustion properties.

In previous research work, we have tried to describe accurately the effect of knitted fabric properties on its flame retardancy.

Through research, we analyzed the effect of knitted fabric dyeing and finishing process on its flame retardancy, so as to reveal the effect of physical and chemical parameters on the flame retardancy of products.

The flammability of fabrics depends on a variety of factors, such as fiber composition, fabric structure, oxygen concentration and environmental conditions (humidity, temperature and airflow speed), but the influence of finishing agents on its combustion performance can not be ignored.

These finishing agents can affect the combustion behavior of fabrics by catalyzing fabrics to produce flammable substances, interfering with flame retardant systems, or indirectly interacting with textile residual dyeing aids and printing adhesives.

It is well known that hard water substances deposited on fabrics, especially those for washing with phosphorus free detergent, can improve the flammability of certain materials and hamper the action of flame retardants.

In terms of printing and dyeing finishing process, early studies showed that acid, reduction, direct dyes and acidic fluorescent brighteners can improve the LOI value of fabrics. On the other hand, the influence of reactive dyes on the LOI value of fabrics depends on the application mode.

Therefore, it is possible for us to introduce nitrogen, sulfur and halogen groups into the dye prescription, or introduce metal ions such as copper and cobalt to improve the LOI value of the fabric. These substances also help to prevent flammable and explosive gases from thermal decomposition of fabrics.

Research shows that disperse dyes, especially nitrogen containing disperse dyes, may have a significant inhibitory effect on the flammability of polyester fabrics.

In addition, the washing agents such as bleaching, washing and softening are generally flammable. If the chemicals remain on the fabric after washing, the flammability of the fabric will be enhanced.

Against this background, it is reasonable to think that the potential combustibility of clothing fabrics greatly depends on the printing and dyeing process.

Early related research was based on a sort of finishing cloth and investigated its effect on flammability of materials.

In this study, we adopted carefully selected knitted fabrics. In previous studies, we have studied the effects of physical parameters of these knitted fabrics on their flame retardancy, so as to determine the influence of various printing and dyeing processes and dyeing auxiliaries on the combustion characteristics of fabrics.

In this way, it is possible for us to evaluate the impact of all possible printing and dyeing processes on the combustion characteristics of a certain fabric.

test

The specifications of three knitted fabrics selected in this study are shown in Table 1.

All fabrics are raw fabrics without dyeing and finishing.

After scouring, these fabrics were then treated with different printing and dyeing processes. The treated fabrics were rinsed by cold water and dried naturally.

Chemicals and test methods

Bleach.

Pure cotton 19.4 tex knitted fabric is bleached with 0.2%, 0.4% and 0.6% hydrogen peroxide (Merc, 50%). The specific formula is shown in Table 2.

Fluorescent whitening.

We chose two fluorescent brighteners Unitex 2BT (Setas chemical company) and anionic, reactive Techowhite NAB Fl SSIG (Toran Kimya Co., TextilColor TextilColor) to study the effect of fluorescent whitening agents on the flame retardancy of knitted fabrics.

These two fluorescent whitening agents are all stilbene derivatives, and their usage in bleaching Whitening Bath is 0.05, 0.1% and 0.2% respectively.

When the whitening agent concentration changes, the concentration of hydrogen peroxide is fixed to 0.4%.

Reactive dyeing: Remazol Navy RGB Gran 150% reactive dye (Dystar Co., BASF), which is very suitable for cotton and viscose fibers, is used to dye cotton and viscose fabrics at concentrations of 0.5%, 1% and 2% respectively.

Disperse dyes.

Disperse dyestuff Dispersol Navy C-VSE (Dystar Co., BASF) was used to dye polyester single side knitted fabric. The dye concentration was 0.5%, 1% and 2% respectively.

Soft finishing.

Soft finishing can make fabric soft, give fabric a smooth handle, and improve the sewing ability of fabrics.

In production, softeners commonly used are anions, quaternary ammonium salts and non quaternary ammonium cation, non-ionic and neutral softeners.

In this study, cationic KF 94, non-ionic WF 95 (Setas chemical company), microemulsion Softycon MES organosilicon (Toran Kimya Co., TextilColor AG), cationic Hagesoft Hagesoft, and non-ionic type