Detection of Flame Retardant Textiles
2015-10-11 08:26 | writer: admin
Almost all textile materials are flammable, even after treatment of flame retardant technology is hard to prevent the fiber in the flame. Just after fire-retardant treatment will decreased the combustion speed of textile materials and left after the fire source can stop burning rapidly, so the flame retardant is not absolute but relative.
With the development of modern city, flame retardant awareness about textile increasing, in order to reduce due to fire accident caused by the textile, avoid unnecessary losses, fabric combustion performance test of attention all over the world in recent years: for textiles with different purposes, the old formulation of flame retardant regulation begins from within the aircraft, textiles the carpet and building materials, expanding into pajamas, furniture sofa sets, taste pad and interior decoration: Britain, Japan and other countries, America also provides a legal form: women, children, the elderly, the disabled person's clothing, pajamas must be marked "flame retardant". Our work in this area is also increasing efforts.
1 Evaluation of Flame Retardant Fabric
Flammability rating fabric mainly from two aspects to consider: one is the ease of ignition, ignition point level namely it shows that fabric fire difficult; on the other hand is the combustion properties of fabric is flame retardant.
The combustion properties of fabric evaluation there are two criteria: one is to judge from the combustion rate of the fabric. That is, after the flame retardant finishing of fabrics according to the specified method and flame contact for some time, and then remove the flame, determination of fabric to flame combustion time and flameless combustion time, and damaged degree of fabric. The flame and flameless combustion time is shorter, the damaged degree is low, said flame retardant performance better fabric; on the other hand, said the poor flame retardant properties of fabrics.
Another is by oxygen index (also known as polar oxygen index) method to judge: fabric burning need oxygen, oxygen index (LOI) is the fiber oxygen needed for the combustion of expression, by which the determination of oxygen index can judge the flame-retardant properties of fabric, oxygen index the higher oxygen concentration required to maintain fuel burn more high, namely expresses more difficult combustion: this index available samples in the mixed gas of oxygen in nitrogen, keep the candle burning minimum volume percentage of Xin need oxygen to say: LOI= oxygen concentration / (oxygen concentration + nitrogen concentration) * 100%
The oxygen index of less than 20%, is a highly inflammable fiber; oxygen index in 20 ~ 26% between genus combustible fibers; oxygen index is the flame retardant fiber in 26 ~ 34% between; oxygen index is not burning fiber above 35%.
2 Testing Methods of Flame Retardant Properties
Combustion test methods varied between the test results of various test methods are difficult to compare with each other, the experiment results can only show the sample combustion performance in a certain extent. Combustion experiment method, combustion is mainly used to test the specimen breadth (carbonization damaged area and length), continued burning time and smoldering time. According to the relative position of the specimen and the flame, can be divided into vertical, inclined and horizontal method.
For China's current} type measuring flame resistant clothing mainly the use of GB / T 5455 ~ 1997 "textile flammability vertical method". The principle is that the burning test box certain dimensions of the specimen are vertically arranged in the provisions, with the provisions of the fire ignited 12 seconds, remove the determination of fire continued burning and smoldering time after time, smoldering stopped, in accordance with the provisions of the method to detect damage length. The method can be used for the flame retardant properties of apparel fabric, decorative fabric, tent fabric; 45 degree tilt method applicable to aircraft inner decoration cloth; level method is suitable for carpet like upholstery fabrics and automotive interior fabric.
The oxygen index method is clamped specimens. The vertical put people transparent burning cylinder, cylinder to mobile oxygen nitrogen flow on the sample ignition end, then observe the phenomenon of combustion, and compared with the prescribed limit continuous combustion time or burning distance: through a series of sample is not the same concentration in the experiment. Can measure the oxygen concentration, oxygen index method is more suitable for the use of the process experiment.