Fluorinated soil retardants

Most fluorinated soil retardants are vinyl polymers, urethanes, or oligomers derived from pyromellitates. Numerous fluorinated soil retardants have been disclosed in the patent literature, but only some examples can be given here (Table 13.2). Usually a vinyl polymer consists of (1) a fluoroalkyl group containing monomer [e.g., 2-(perfluorononyl)ethyl acrylate, the methacrylate CH=C(CH3) COOCH2CH2C F2 +i, or CH=C(CH3) C00CH2CH2(CH3) S02(CF2)8F], (2) a nonfluorinated alkyl acrylate or methacrylate (e.g., butyl or stearyl acrylate or methacrylate), and (3) a cross-linkable monomer for durability (e.g. A methylo- 

Wehowsky et al. [44] reacted epichlorohydrin with C6 i2Fi3 250H. The product obtained was reacted with toluene diisocyanate and oligoepichlorohy-drine to yield an urethane useful as a soil retardant. 

Chang et al. [45] reacted 1.5 mol methylene bis(4-phenyleneisocyanate) with 1 mol V-ethyl(perfluorooctane)sulfonamidoethyl alcohol. The remaining isocyanate groups were converted to carbodiimide groups and reacted with dibutylamine to yield a guanidine derivative. 

Smith [46] reacted a tri-isocyanate or higher order isocyanate with C8F]7S02N(CH3)C2H40H, then reacted 5-50% of the isocyanate groups in the reaction product with water and, subsequently, reacted the remaining isocyanate groups with poly (ethylene glycol) (Carbowax 600). 

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. 

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Hydrocarbon repellents and their mixtures with fluorinated repellents, silicone and fluorosilicone repellents, and fluorinated repellents are described in Chapter 12. Fluorinated soil retardants are discussed in Chapter 13 and soil- and stain-resistant carpets in Chapter 14. 

Table 13.2 Examples of Fluorinated Soil Retardants for Carpets... 

Carpets on the floor are subjected to soiling under severe noiechanical conditions. Particulate soil is transferred from shoe soles onto the carpet while the carpet pile is being compressed, rubbed, and twisted by the mechanical action of the foot traffic. The soil particles left on fibers are ground into the fiber surface by the continuous traffic. The mechanisms of soiling with particulate soil and the deterrence of soiling by fluorinated soil retardants have been described in Chapter 13. 

Telomer B alcohol [4]. Scotchgard FC-1395, a fluorinated polymer, was made by 3M [5]. The fluorinated soil retardant is undoubtedly the most important component of the soil and stain-resist finish on the carpet because soiling by foot traffic is a daily occurrence, whereas staining with liquids is an accidental event. 

Type of fibers and heat-setting history Stain-resist agent and its chemical and physical properties Application process for the stain-resist agent Fluorinated soil retarder... 

The limitations of the model for dye-site blocking has made it necessary to invoke a barrier model as well. A fluorinated soil retarder functions as a repellent nonionic barrier on the fiber surface. The fluorinated polymer does not form a continuous film around the fibers and cannot completely prevent the stain from diffusing into fibers. An additional barrier is needed in the subsurface of fibers as well to hinder the diffusion of the stain. 

When it was recognized that fluorinated soil retardants alone cannot provide a complete protection against staining with liquids, the fibers were treated with stain-resist agents. 

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