Oil repellency tests

TABLE 1. Water/alcohol and oil repellency testing of fabrics modified with perfluoroacrylate monomer to confer a hydrophobic/oleophobic repellent surface. 

Fabric Sample Water/Alcohol Unwashed Repellency Test 10 Wash Cycles Oil Repellency Test ... 

AATCC TM 118-Oil repellency hydrocarbon resistance test, equivalent to ISO 14 419... 

Oil-repellent fabrics resist wetting by oily Hquids and repel oilbome stains. The level of performance of such fabrics is judged by AATCC Test Method 118. 

Test Methods. The test methods used for water or oil repellency ate quite varied, in accordance with paper or paperboard type and end use. Two tests commonly used to measure water repellency, the Hercules Size Test and the COBB Test, as well as others have been summarized (55,69,70). 

The Kit Test (T-559 pm-96) can be used to measure oil repellency when there is no physical barrier to oil penetration such as that provided by a film, foil, or waterproof coating (71). Another measure of oil repellency is the Turpentine Test (T-454 om-89) (71). If a physical barrier is present, tests that measure the weight of oil pick-up or show-through under conditions that simulate the end use are appropriate. 

Repellence tests with essential oils at 90% concentration indicated that five essential oils were effective repelling mosquitoes for 90 min (Table III). The essential oil of Acantholippia seriphioides was repellent even at the lowest concentration tested (12.5%). Repellence by this essential oil was expected because its main components are p-cymene (53%) and thymol (47%), both components showed repellent activity for approximately Ih against mosquitoes species (46). At concentrations of 12.5%, Aloysia citriodora, Baccharis spartioides and Rosmarinus officinalis showed the longest repellency times. Comparisons of the principal components of each essential oil suggest that limonene and camphor were the main components responsible for the repellent effects (46). 

Table 3.4 Standard test liquids for oil repellency (adapted from AATCC, 1997)...

American Association of Textile Chemists and Colorists (AATCC) (1997), AATCC Test Method 118 Oil Repellency Hydrocarbon Resistance Test, Research Triangle Park, NC, AATCC. 

Oil repellency can be evaluated by AATCC Test Method 118-2002. Drops of hydrocarbon with various surface tensions are apphed to the fabric sample and the... 

Technical Manual of the American Association of Textile Chemists and Colorists, Vol. 64. 1989 (Library of Congress Catalogue Number 54-34349). Oil repellency AATCC 118 Water repellency isopropanol test Spray test AATCC 22. 

Water and oil repellent finishes, normally perfluoroalkyl sulfonate (PFAS) and perfluorooctane sulfonate (PFOS), are not to be used, and their threshold limit is 1 pg/m each in the coated material whereas all other PFAS forms, the threshold limit is 20 pg/kg and MSDS is required to be supplied for verification. The test method is based on solvent extraction and GC-MS or HPLC-MS. For per fluoro carboxylic acids and salts (PFCA), the limiting value is 0.05 ppm or sum total is 0.1 ppm. 

The area covered by a hydrocarbon liquid within a certain time period is correlated with the oil repellency of the fabric (Fig. 11.8). Usually, oil repellency is tested inder static conditions by using a series of hydrocarbon liquids of different surface tensions (see Section 12.5). A measured drop of the liquid is placed on the fabric. After 30 s, the drop is removed and the wicking of the liquid into the fabric is observed. If the drop has not left a significant wetted spot on the fabric, the next higher numbered liquid of lower surface tension is placed on the fabric, until noticeable wetting occurs. Instead of using different hydrocarbon liquids, the area covered by the liquid of the lowest surface tension in the series can be measured to determine oil repellency. 

Soil retardants can be applied to fibers, yams, fabrics, or carpets by spraying, padding, kiss-roll, or foam application techniques. Some soil retardants are applicable also by exhaust methods. Spraying is the most popular method for applying soil retardants to carpets. The required amount of a soil-retardant product is typically 0.5-1.6% of the weight of dry face fiber or about 200 ppm as fluorine. Usually, the soil retardant as applied as the last step before the carpet is dried. The presence of a fluorinated finish on the carpet can be confirmed by an oil-repel-lency test, based on the AATCC 118-1997 test (see Chapter 12), or a water-repel-lency test. Fuorier transform infrared and x-ray photoelectron spectroscopy (ESCA) (Chapter 9) provide semiquantitative information on the fluorinated soil-retardant concentration on the fibers. 

---