AATCC 30-Antifungal Activity, Assesment on Textile Materials: Mildew and Rot Resistance of Textile Materials. AATCC 30: 2013 Test.
Test accredited by ENAC (National Accreditation Entity).
The two objectives of this test method is to determine the sensitivity of textiles to molds and deterioration, and to evaluate the effectiveness of fungicides in textile materials. The two important considerations when evaluating tissues in relation to fungal growth are: a) tissue deterioration (putrefaction), and b) growth, although it does not cause the deterioration of the product, but alters its appearance (moldy) frequently with an unpleasant and rancid smell. Some type of previous exposure may be indicated according to the final use. For example, when the tissue is used at elevated temperatures and the fungicide can be volatile, preliminary exposure in an oven may be indicated; When the fabric is used in tropical areas or outdoors with rain, leaching must be carried out before applying the molds. Whenever possible, the tissues should be exposed to the expected conditions before performing the test. The standard indicates four types of tests (I, II, III and IV) that can be performed separately or in combination depending on the type of exposure to which the materials are subjected. Test I must be used for tissues that will come in contact with the ground; tests II or III should be used when tissues that will never come into contact with the soil or tropical environments, testing II, recommended for tissues containing cellulose, and test III for other tissues; The IV test is indicated for fabrics used outdoors and without contact with the ground.
The I test is considered the strictest and should be performed only with tissues that are going to be in contact with the ground, such as sandbags, awnings, tents, ..., as well as to test tissue fungicides experimentally. The test uses tissue samples of 15 x 4 cm, with the longest dimension parallel to the deformation and disentanglement of 0.5 cm wide, and in the case of tissues with less than 20 fibers in 2.5 cm to a certain number of fibers to provide a 2.5 cm sample. The number of pieces of tissue is 5 for each treatment, for the control and reference tissue. The tissue samples should be kept between 2 and 16 weeks in contact with earth as required by the manufacturer, with a humidity of 25%, temperature of 28ºC and relative humidity of 83%.
Test II (agar plate with Chaetomium globosum) is used to evaluate the resistance of tissues containing cellulose that do not come into contact with the soil, and can also be used to evaluate the uniformity of the fungicide treatment. Tissue discs of 3.8 cm diameter are used in the test.
Test III (agar plate with Aspergillus niger) uses a fungus that can develop in the tissues without causing its deterioration, but its development can cause undesirable effects and alter its appearance (moldy). This test is used to evaluate tissues where the growth of these fungi is important. The test uses 4 cm diameter circles of tissue samples, treated and untreated, with antifungals. Fungus cultures should be maintained for 14 days to obtain the spores to prepare the inoculation suspension of the plates on which the tissue discs are placed that are kept in contact for 14 days before microscopically evaluating the percentage of the surface of the tissues discs.
Test IV (moisture jarr with mixed spores of Aspergillus brasiliensis [syn. A. niger], Penicillium varians [syn. Talaromyces varians] and Trichoderma viride) is used to determine the fungistatic efficacy of treatments intended to control molds and growth of non-pathogenic fungi in materials or surfaces used outdoors without contact with the soil, usually water-proff. For this, strips of treated and untreated tissues, saturated in nutrients are contaminated with a suspension of spores of molds and are incubated at a relative humidity of 90%, and observed for 4 weeks. The fungal cultures for the spores should be maintained for about 10 days, to prepare the suspension with which the tissue samples will be inoculated, to be incubated for 14 days (unimpregnated tissue with cellulose) or 28 days (impregnated tissues without cellulose).