Competitor, Kolcheva D. V.

Donetsk national university of economics and trade named after Mikhail Tugan-Baranovsky, Ukraine

Use of flame retardants to provide fire safety of textile materials

Each year huge amount of people die through the accidental effects of fire. For instance, researching results of European Flame Retardants Association indicate that every year nearly five thousand people die in fire. Disastrous fires in the domestic environment and public places, such as transport, theatres, clubs, hospitals, hotels, hostels, educational establishments, stadiums, railway stations and so on, regularly make the headlines in the media. It causes death and injury not only for people but also brings great financial loss.

The analysis of fire progress shows that on the early ignition stage, textile materials are unsafe and can stimulate fire spread over the building and obstruct exit routes in establishments of the mass gathering of people. The speed and extent of growth of a fire are often determined by the properties of the materials adjacent to the source. Easily ignited materials such as curtains, decorations and upholstery can lead to a rapid and accelerating growth of heat and flames that help to establish the fire.

It is possible to complicate the process of flame spreading by special substances for textile materials – flame retardants, that are not widely used, but nowadays it is getting more practically important because of moderate cost and manufacturing technology. Textile materials finished by flame retardant can prevent fire from spreading and ensure that it is kept within its original confines. It is important to make the distinction that flame retardant treatment of textile materials will make them less easily ignited and less likely to allow the spread of fire but it will not make them non-burning.

Actual industry uses phosphates, borates, sulphates, titanium and stibium salts, inorganic and organic nitrogen-containing and haloid-containing composition as flame retardants. Such flame retardants show differing effects on different textile substrates.

Nowadays the most famous flame retardants are manufactured into the following countries: Russian Federation, Germany, France, Switzerland, the Netherlands, Belgium, Italy, Spain etc. (figure 1).

Figure 1 – Structure of flame retardants for textile materials under the manufacturing countries

In spite of the complex interplay of the factors that influence fire process, it is possible to consider different principal methods of effecting flame retardant products.

Classification of the principal methods of action of flame retardants:

1. energy consuming or endothermic reaction (materials that, by their thermal destruction, use energy without releasing flammable gasses are effective as flame retardants);

2. release non-flammable gases (if the endothermic reaction can also lead to the release of non-flammable gasses then a stronger flame retardant effect is produced by the dilution of the flammable gasses and the oxygen);

3. flame retardant effects through barrier formation:

- barrier formation by the dehydration of cellulose (because of cellulose containing substrates that are special in having the ability to achieve excellent flame retardant effects using dehydrating acids. Such reaction involves the release of water as a non-flammable gas and the formation of a carbonized char that will only ignite above the temperature given by the burning of the cellulose);

- barrier formation by chemical intumescence (flame retardant intumescence systems by an increase in temperature causing the material to expend and form a heat insulating layer);

- barrier formation by physical intumescence (chemicals have the ability at raised temperatures to substantially increase their volume, that’s why the process consumes energy and leads to an effective barrier layer being formed);

- barrier formation by Melting (non-flammable chemicals that melt at a sufficiently low temperature can form a barrier that protects the textile materials form the flame source).

4. formation of free radicals (the process of textiles burning has previously been described as the oxidation of the released flammable gasses in the presence of oxygen);

5. changing the melting behavior (melting point of a textile polymer can be significantly reduced, that has the effect of making textile polymers melt away from a heat source more rapidly and thus avoid ignition, making them less easily flammable).

Thus, the necessity of conduct of fireproof treatment of textile materials is processed by the special substances - flame retardants. Nowadays we have a wide choice of such treatments available on the market. Flame retardants can be applied to textile materials using the following methods: padding, spraying, dipping and coating. We have considered a classification of principle methods of action of flame retardants, in which main mechanisms of their influence on textile materials are presented.