Perdelik, döşemelik ve halı tipindeki tekstil malzemelerinin yanma özelliklerinin çeşitli deneyler yapılarak incelenmesi ve bu deneylerin karşılaştırılması

Abstract

Günümüzde tekstil malzemelerinin yanma özelliklerine gittikçe artan bir önem verilmeye başlanmasıyla birlikte, bu özelliklerin değerlendirilmesi için farklı test metodları ve standartların geliştirilmesi yönünde bir eğilim oluşmuştur. Test edilecek malzemenin tipine göre kullanılacak test metodu değişmektedir. Kullanılan test metodunun uygunluğu büyük önem taşımaktadır. Bu tezde ev tekstili tipindeki perdelik ve döşemelik kumaşlar ile halılar çeşitli testlere tabi tutularak yanma özellikleri incelenmiştir. Farklı testlerden elde edilen sonuçlar değerlendirilerek testler arasında bir karşılaştırma yapılmıştır. Perdelik ve döşemelik kumaşlar için yapılan testler sonucunda gramajın alev yayılma hızına etki eden önemli bir faktör olduğu bulunmuştur. Dikey test sonucunda bulunan alev yayılma hızlararın yatay test sonucunda bulunan alev yayılma hızlarından yüksek olduğu, ancak numunelerin her iki testte de benzer sonuçlar verdiği görülmüştür. Bu iki testin bu alanda kullanılmasının uygun olduğu, ancak bazı durumlarda yetersiz kaldığı düşünülmektedir. Halılar için yapılan kızgın metal somun ve metenamin tablet testierinin sonuçlan değerlendirildiğinde bir testte iyi sonuçlar veren numunenin diğer testte daha kötü sonuçlar verdiği görülmüştür. Bu da iki testin birbirlerinin yerine kullanılamayacağını göstermiştir. Halıların yanına özellikerinin değerlendirilmesinde bu iki testi kullanılmasının uygun olduğu düşünülmektedir.

Textiles cany great importance in human-being's life: As a cloth or as a bed, as the interior parts of his car or as a covering material on the wall of his house, textiles are always in human-being's Hfe. In the past, textiles were used for hiding some parts of the body or preventing one's self from heat or cold. But, now, textiles are preferred to have features like being healthy, esthetic or having a protective performance against some extreme conditions. There is an improvement in the features of the textiles going parallel with the development of the technology. During the past 40 years, there has been much research and publication in the area of fabric flammability and its prevention and concurrent activity in the field of test methods, legislation and policy. Initial work was concerned with performance of individual textile fabrics, but, more recently, the activities have been directed towards garments or clothing systems and also towards mattresses (bedding) and upholstered furniture. Flame retardancy of textiles is an important feature from the point of view if the safetiness of textiles is discussed. For this reason, increasing importance is given to the finishing processes applied for flame retardant (FR) textiles. FR materials are especially used in the areas of military applications, vechicles, clothing textiles and decorative materials. The burning behaviour and FR characteristic of textiles are also important in export. Especially for Turkey, being in an exporter country position in the field of textiles, it is important to satisfy the needs of the importer countries. The producers and also the consumers should be VI aware of the importance of the burning behaviour and FR characteristic of products. The burning of a textile material occurs in four steps: a) The heating of the material b) The thermic breaking down of macromolecules-pyrolisis c) Ignition d) Burning / If a certain amount of energy is given to the product, the surface temperature increases according to the thermic values of the product like: - specific heat, - heat conductivity, - melting heat, - evoporation heat. Pyrolisis begins when the breaking down point of the product is reached. The following products are obtained at the end of the pyrolisis: Energy- L Burnable gasses Unburnable gasses Oxidation -> Flame fibres f- Liquid breaking down products Carbonized wastes How great is the amount of the burnable gasses among these products, that easy is ignition. If the amount of the other products is greater, ignition and burning are difficult. Ignition can be defined as the transfer of a system from the metastable position into the burning position. Burning is started by the VII burnable gasses that ignite in the presence of oxygen in the air at a certain temoerature. certain temperature There are some methods to give FR characteristic to textile materials: a) Some fibres are FR themselves because of their structure. Ex; Kevlar, Durette, glass fibres, carbon fibres, etc. These fibres can show FR characteristic without being treated by a finishing process, but because of not showing enough textile features and being very expensive, they cannot find a great application. b) Some chemicals are added to fibres before spinning of synthetic fibres. c) The surface of the textile is treated with the chemicals that give FR charactersitic to the product. This is the most used method. Ex; DMDHEU, THP, Myflam, Pyrovatex, etc. The chemicals that are used in the FR finishing processes should have some properties: 1. They should be resistant to washing and dry cleaning. 2 They should not let crystallization to occur on the surface of the material. 3. They should not decrease the breaking strength of the textile material. 4. The handling of the material should not be rough after treatment with the chemicals. 5. The production and usage of the chemical should be healthy and environment-friendly. 6. Poisonous gasses should not occur during the burning of chemicals. There are various test methods and standarts to investigate the burning behaviour of textile materials. Test methods vary according to the material type to be tested and the aim of the usage of the material. In the literature, weight per unit area is found to be the most effective factor in evaluating the TPP (Thermal Protective Performance) of the materials. If weight per unit area increases, TPP increases. Also weight per unit area effects the flame spreading speed. Flame spreading speed increases, if weight per unit area decreases. The air-permeability VUl of fabrics effects the TPP values. If air-permeability increases, TPP decreases. For garment flammability and upholstered furniture flammability, the reaction to flame or high temperature of fabrics, sewing threads, seams, and other 'accesories' is very important. The thermal degradation of accidental ignition but also because fabrics and yarns are often exposed to high temperatures under a wide range of conditions during processing. Although the literature contains many oblique references to the effects of heat on yarns and fabrics, particularly specific high- temperature-resistant fibres, there appears to be a suprising lack of papers dealing with the changes in physical properties of the common fibres after controlled exposure to elevated temperatures. In construction of most textile products, the seams are made by sewing techniques involving the use of thread. The way in which the thread or seam reacts to flame or high temperatures is therefore a very important part of the way in which the end item will perform when subjected to such flame or temperature. Although there are 'standart' stiches, seams and stichings, the types and sizes found are virtually unlimited. It is important to chose the correct type of test for the material to be tested. In this thesis, the burning behaviour of home textiles like curtain fabrics, upholstery fabrics and carpets is investigated by the help of different tests. The results of these different tests are evaluated and compared. The materials tested are obtained from industry. 11 different upholstery fabrics of lxl m dimensions, 7 different curtain fabrics of 0.5 m width and 4 different carpets of lxl m dimensions are tested. The tests made for upholstery and curtain fabrics are as following: a) Determination of warp-weft /cm b) Determination of the fibres and the mixture ratio c) Determination of weight per unit area (g/m2) d) Vertical burning test IX e) Horizontal burning test The WINTREE FLAMMABÎLİTY SPEED TESTER is used for the vertical and horizontal burning tests of the curtain fabrics and upholstery fabrics. The tests are made by following the instructions in the handbook of the equipment. The flame spreading speeds are calculated. The uphostery fabrics were made from Polyester, Cotton, Acrylic and Polypropilen. There are 2 Cotton/Polyester/Cotton blend, 2 Acrylic/Cotton blend, 3 Polyester/Polypropilen blend, 2 Cotton/Polyester blend (FR), 1 100 % Polyester and 1 100% Acrylic fabrics. After the vertical and horizontal tests were made, the flame spreading speeds (FSS) found as a result of the vertical tests were higher than the FSS found as a result of the horizontal tests. This is because when the test is made in the vertical position the flame spreads upward fastre than it spreads horizontally. The length of the flame is greater than its width. In the horizontal position the flame is in contact with the fabric only by its width, but in the vertical position both width and length are in contact with the fabric. This phenomen increases the speed. If weigth per unit area inreases, FSS decreases as shown inthe figure below: ?lame Spreading Speed (mm/sn 7 6 5 4 3 2 1 0 0 200 400 600 800 Weight per unit area (g/m2) Figure: The correlationnbetween the weight per unit area and flame spreading speed WW Brough et al [14] also found that if weigth per unit area increased, the rate decreased. FSS values of Polyester fabrics could not be calculated in the horizontal test, because the polyester fabrics burned by melting for a short time and the flame couldn't reach the stop cord. Similar blends showed similar burning behaviour. For example, 52/28/20 Acryhc/Polyester/Cotton blend A (397 g/m2) and 39/31/30 Acrylic/Polyester/Cotton blend D (405 g/m2)'had similar FSS values. Although the curtain fabrics were made from 100 % Polyester and although there were fabrics of similar weigth per unit area, there was not a visible correlation between the weigth per unit area and FSS. For example, P. 1001 (82.4 g/m2) and P.3011 (83.6 g/m2) didn't have similar burning rates. The values found for P. 1001 are much higher than the values found for P.3011. The reason for this can be the patterns and the nappy parts on the fabric surface. There is more material on the nappy parts and this decreases the burning rate. Fabrics coded as B, F, H, P.K127 and P.K131 had nappy surfaces. During the burning of these fabrics, FSS values were observed to be lower. The burning rate decreases, because on the nappy parts there is more material. Also the ignition time of these parts are longer. During the burning of fabrics coded as F and H, when the flame came to the nappy part, it changed direction and continued to spread on the under-surface of the fabric which was not nappy. The flame could spread faster on this side Some pieces from the burning fabric fell down during the burning of the fabrics coded as A, C, D, L, M, P.K131 and P.K127 and sometimes these pieces continued to burn on the ground. This may be very dangerous in real life fires, because it helps the spreading of the flame. If the FSS values of horizontal and vertical tests are compared, a graphic as below is obtained: XI Vertical WWS (mm/see) t o in O m m i^gur©: 5 10 15 20 25 30 Horizontal FFS( mm/sec) The correlation between the vertical and horizontal flame spreading speeds. The tests made for carpets are as following: a) Determination of the type of the fibres b) Determination of nap heigth and carpet heigth c) Determination of weigth per unit area d) Hot metal nut test e) Methenamine tablet test Hot metal nut test is made according to BS 4790. Methenamine tablet test is made according to TS 5193, ASTM D 2859, BS 6307 and ISO 6925. The diameters of the burned area both on the surface and on the under-surface are measured. The burning times are deterrnined. The burned area in the nut test was larger if compared with the tablet test. The burning of the under-surface of the carpet is more visible in the nut test. This may be because of the weigth of the nut (30 g) being higher than the weigth of the metheamine tablet (0.150 g). The nut xu applies more pressure than the tablet on the carpet and so the depth of burning is greater. The type of the covering material of the under-surface is important in the burning behaviour of the under-surface of the carpet. If the ignition of the covering material is easier, the burned area is larger. The burning time is longer in the tablet ^est, because the tablet was not taken from the surface of the specimen and it continued ti bum, but the nut was taken after 30 seconds. Vertical and horizontal tests are convenient for evaluating the burning behaviour of the upholstery fabrics, but they were not enough for evaluating the burning behaviour of FR fabrics. A more advanced test should be used for evaluating the TPP of FR fabrics. For upholstery fabrics upholstered furniture simulations can be used for better evaluating the burning behaviour, because like this together with the fabric also the foam, seaming threads, accessories,etc. effect the burning. Ao For curtain fabrics a test in which the fabric is held under its own weigth with draperies if wanted can be developed. For carpets the hot metal nut test and the methenamine test are convenient for evaluating the burning behaviour of carpets, but the burning behaviour of carpets changes in the two tests, so the tests should not be used instead of each other.