Soiling and staining

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. 

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Chemical bleaching is used to remove colored non-washable soils and stains adhering to fibers and is accomplished by oxidative or reductive decomposition of chromophoric systems. Only oxidative bleaches are used in laundry products to a great extent. 

The aforementioned effects combine to provide greatly enhanced removal of many soils and stains by a formula with builder compared with a formula without. 

Abrasive cleaners arc used lo remove soils and stains from hard surfaces that are durable lo the scouring action. Such surfaces include stainless steel and porcelain plumbing fixtures, metal and ceramic cooking utensils, and various stone, metal, and ceramic building surfaces. Typically, these products consist of a very high level of abrasive (commonly silica flour) with moderate to low levels of a dry chlorine bleach (KDCC or chlorinaled trisodium phosphate) and low levels of surfactant (LAS) and builder (STP) for wetting action and improved stain removal... 

Emulsifiable concentrate formulation of diazinon, diluted to 1.0% a.i. was used to contaminate a 50/50 blend of cotton and polyester. A single warm-water wash (49°C) results in approximately 4% diazinon remaining however, if the fabric is pretreated with Spray n Wash (a prewash commercial soil and stain remover containing a blend of... 

Emulsifiable concentrate formulation of malathion, diluted to field strength (0.5% a.i.) was used to contaminate 100% cotton. A single warm water wash (50°C) results in 6% malathion residue remaining on the fabric. A double wash results in approximately 3% residue remaining. Using a bleach/soak pretreatment, a prewash soil and stain remover, or an additional wash does not significantly improve residue removal. 

Emulsifiable concentrate formulation of Triallate, diluted to field strength concentration (1.8% a.i.), was used to contaminate cotton twill fabric. The best laundry procedure is to pretreat the work clothing with a pre-wash commercial soil and stain remover containing a blend of surfactants and solvents, launder in hot water (60°C), and then launder a second time. Approximately 18% of the pesticide remains in the fabric using the above procedure after a single wash when no pretreatment and warm water (50°C) were used, as much as 48% of the Triallate remained. 

The removal of soils and stains by application of solvents to the tapa using the suction feature of the table was not successful. A Bolivian tapa hood with a painted decoration was chosen for testing of stain removing capabilities. The hood had been defaced with green felt-tip marker ink, which proved soluble in a variety of solvents, including both acetone and water. 

In the textile Industry, the term finishing Is used to denote the application of chemicals exclusive of coloring agents to Impart certain esthetic effects such as drape, handle or wrinkle resistance and to affect physical properties such as resistance to shrinkage, resistance to seam slippage or soil and stain resistance. 

Antiredeposition Polymers. The surfactants employed in synthetic detergents are effective in removing soil and stains from the surface of the washed fabric. Under heavy soil loading, there is a tendency for these soils to redeposit on the fabric. Various charged polymers have been found to prevent soil redeposition. Sodium carboxymethylcellulose (NaCMC) is effective in reducing soil redeposition at a formulation level of 0.1-0.5 percent. 

Enzymes. A number of different enzymes have been developed for use in detergent systems to remove common soils and stains. Protease enzymes are used to cleave the protein-based soils into smaller pieces more easily removed by the detergent system. Lipase enzymes are used to cleave lipid bonds resulting in fatty acid and glycerol. Lipase enzymes work better at elevated temperature and tend to become active in the... 

As a finishing agent, POMOCO SR 92 can be used as an extender for some types of fluorocarbon soil and stain release finshes. Partial replacement of most fluorocarbons will give equally good results, and in some cases it will actually improve the performance of the fluorocarbon. 

Fluorocarbon extender resin for soil and stain release finishes. 

HOO oxidizes bleachable soils and stains. The most used source of hydrogen peroxide is sodium perborate, known as sodium peroxoborate tetrahydrate, NaB03-4H20, that in crystalline form contains the per-oxodiborate anion [4, 17]. 

Carpet. Carpet, an important textile, may also be treated to provide water and oil repeUency however, the principal functions of the current carpet treatments are to provide soil and stain resistance. High quaHty carpets, especiaUy those made from njion, polyester, or wool, have a significant proportion of the surface coated with fluorochemical materials. The treatments can be spray-appHed to a finished carpet or appHed direcfly to the fiber during the spinning or dyeiog operations. Suitable fluorinated resin materials are readily available from 3M or DuPont. 

In recent years, researchers have explored electrochemical methods for use in automatic dishwashing for sanitization and stain removal. In dishwashers, it has been observed that electrochemical cells operate by making use of the water electrolysis process, where OH present in the water from the electrolytic dissociation of water molecules donates an electron to the anode and is therefore oxidized to oxygen gas, which can be removed from the system. As a result, is enhanced at the anode-water interface, and enriched acidic water is produced. The advantage of this electrolyzed water is that it can provide improved cleaning, stain removal, and sterilization benefits in automatic dish care. Combined with ADD compositions, electrolyzed water can be effective at removing a number of soils and stains from dishware. Additionally, the combination of electrolyzed water with ADD combinations may alleviate the need to add additional bleach to the detergent. 

A wide variety of technical options is used to improve the storage stability of bleach systems under alkaline conditions and to avoid negative interactions with sensitive ingredients such as enzymes, optical brighteners, or fragrances (see Section 16.3). Controlled release of these compounds, first the enzymes, followed by bleach, and last the perfume, guarantees complete soil and stain removal and adds whiteness as well as a fresh scent to the cleaned garment. 

Bleach (in care of textiles) A product for brightening and aiding the removal of soils and stains from textile materials by oxidation that is inclusive of both chlorine and nonchlorine products. 

Cleansing of materials (substrates) implies the removal of soil and stains. A wide variety of stains and substrates are encountered. For instance, textiles may be of natural origin such as cotton, wool, or natural silk, or are made of synthetic fibers, such as nylon, polyester, or polyacryl. Cotton is cellulose that has an intermediate hydrophobicity wool and natural silk are proteins, both rather hydrophobic and in most cases negatively charged. Synthetic fibers are usually polymers of which the backbone is characterized by a series of repeating units such as peptide units (in nylon), ester bonds (in polyesters), and cyan groups (in polyacryl). 

There have been some reports of the addition of PTFE to plastic resins to improve their soil and stain repellency and/or barrier properties however, the addition of noncrystalline fluorochemicals is more common for this purpose [43]. 

Figure 5.3 Detergents remain the most Important use of surfactants. Some commercial examples are shown here. Surfactants play a major role in cleaning the huge variety of different stains (types of dirt), for both hard and soft surfaces. The components In soil and stains are not well-defined. Both contain any number of species, in varying quantities. Even so, we can put them Into several categories, which require different methods of treatment.

TABLE 19 Detergency of Ethoxylated Amides on Particulate Soils (dust sebum, standard soil, clay). Oily Soils, and Stains (chocolate milk, coffee, grape juice, grass, ketchup, tea) Using Ig/L at 100°F... 

Cleaning of the body and clothes has been around for centuries. However, prewash soil and stain removers made their appearance in the 1960s. With the ban of phosphates in laundry detergents, clothes were not becoming as clean as they once were. The use of synthetic fibers also increased the need for a product to treat and remove stains. 

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