A kinetic study of fabric detergency

The kinetics of soil removal were investigated under domestic laundry conditions by incorporating small swatches of four artificially soiled test fabrics into a standard load of clean cotton goods. This prevented soil redeposition from affecting the soil removal rate. Two runs were analyzed, one with an anionic and the other with a nonionic detergent. Assessment of the amount of soil remaining on the fabric was made by reflectivity measurements interpreted according to the Kubelka-Munk equation. First-order kinetics were found to prevail for periods ranging from the first 6 min of the wash cycle to the entire 20 min, depending upon test fabric and detergent. For these lengths of time, the rate of soil removal was directly proportional to the amount of soil remaining on the fabric. The 8 first-order rate constants had rather similar values, varying at most by a factor of 2.3. The average value, 0.109 min⁻¹, corresponds to a 6.4-min wash period for removing one-half of the soil and to a 21-min period for removing 90% of the soil from the soiled fabric. The magnitude of the response of the four artificially soiled test fabrics to the two detergents is compared and discussed in terms of the soiling materials. The nonionic detergent was more effective in cleaning a fabric soiled mainly with kaolin and wool fat, while the anionic detergent was more effective with a fabric containing large amounts of liquid oily soil plus carbon black and oleophilic bentonite.     

A kinetic approach to detergent synergism

It is shown that kinetic theory can be applied to the removal of a heterogeneous soil by detergent solutions. By assuming first-order kinetics, const permitting rate comparisons were calculated for the removal of baked P³² milk films from stainless steel test discs by NaOH, a nonionic surfactant, and combinations of the two. Values for E^* were obtained from Arrhenius plots. The data indicate an abrupt change in the activity of the nonionic detergent occurred as it passed through the cloud point region. Synergism was demonstrated in solutions of NaOH-surfactant maintained below cloud point temps; at higher temps, this synergism was apparently lost. Possible explanations of synergism and detergency as affected by the could point phenomenon are discussed. *** DIRECT SUPPORT *** A03O2193 00002     

Study of detergency. I. Effect of the concentration and the kind of detergent in hard water

The effect of concentration and kind of detergent, and nature of oil-on-oil removal efficiency in hard water was studied. Maximum oil removal efficiencies are shown at the same water hardness for a given oil. As the concentration of detergents increases, the water hardness at maximum oil removal efficiency increases and the sharpness of the oil removal peak is lessened. A linear relationship between concentration of detergent and water hardness at maximum oil removal efficiency was found. This relationship is dependent on the nature of the oily soil and kind of detergent.     

Optimization of nonionic/anionic surfactant blends for enhanced oily soil removal

Previously reported results for alcohol ethoxylate surfactants have shown that optimum removal of both nonpolar and sebum- like liquid soils from polyester/cotton fabric occurs at the phase inversion temperature (PIT) of the surfactant- water- soil system. A similar correlation between phase inversion and optimum detergency has been identified for detergent systems containing mixtures of nonionic and anionic surfactants such as alcohol ethoxylates and alcohol ethoxysulfates. Experimental techniques other than direct detergency studies are described which allow determination of the optimum nonionic/ anionic surfactant ratio for removal of a particular soil at a specified temperature. In addition, implications of these results for development of temperature- insensitive detergent formulations containing alcohol ethoxylates are discussed.     

有机硅表面活性剂在农药增效剂及油污清洗剂中的应用

介绍了有机硅表面活性剂的结构、特性及在农药增效剂和油污洗涤剂配方中的应用效果。有机硅表面活性剂用于除草剂、杀虫剂中，能显著提高农药的除草、杀虫效果，延长其作用时间；用于油污清洗剂中，能将油污脱除率提高到80％以上。     

Function of lipase in lipid soil removal as studied using fabrics with different chemical accessibility

Fatty stain removal is enhanced by the inclusion of lipase in washing compounds and leads to increased lipid removal from within the fibers. Cotton fabrics with varied morphology/chemistry were investigated to study the accessibility of soil in textiles to detergent and lipase. Three cotton fabrics (untreated, mercerized, and carboxymethylated cotton), differing in chemical accessibility, and Tencel^TM lyocell fabric, a microdenier manufactured cellulosic fiber, were subjected to three treatments—unwashed, washed with detergent, and washed with lipase—so as to understand further the effects of fiber morphology on lipase effectiveness. Both detergents and lipase removed more soil from the more chemically accessible and hydrophilic textiles. Lipase increased lipid removal for all fabrics and all morphological locations on the fiber, including fiber surfaces, interfiber capillaries, small capillaries, and the center of the yarn bundle. Lipase removed significant quantities of soil from the lumen in untreated and mercerized cotons; these fabrics showed the largest total increases in amount of lipid removed by lipase. When the fiber surfaces were smoother and the fiber structure was less open and not carboxymethylated, i.e., the mercerized cotton fabric, more lipase benefit was observed (72% of the residual soil left after washing with detergent was removed when lipase was added). The total soil removal from the mercerized cotton fabric by use of lipase was equal to that observed for the more open, hydrophilic carboxymethylated fabric and for the Tencel, which has no lumen or other morphological features of natural cotton such as crenulations. Lipase appeared to enhance lipid removal under conditions where removal by the detergent surfactant system was limited. Furthermore, we concluded that lipase acted to remove lipid soil from within the fibers by functioning at the interior surfaces of microfibrils and pores within the fiber structure at the lipid-water interface.     

Kinetic studies of detergency. III. Dependence of the dupré mechanism on surface tension

The kinetics of the removal of thin films of pure radioactive tristearin from a stainless steel surface by detergent solutions in a circulation cleaning system were used to study the effect of the surface tension of the detergent solution on the Dupré mechanism and the flow mechanism. Lowering the surface tension reduced the effectiveness of the Dupré mechanism for both species 1 soil and species 2 soil, as expected. Lowering the surface tension increased the efficiency of the flow mechanism for both species of soil, but, at the present time, it is not known how much of the increase can be ascribed to the lowered surface tension, and how much is due to the increased concn of the surfactant that was used to lower surface tension.     

Improvement of cotton cloth soil removal by inclusion of alkaline cellulase from Bacillus sp. KSM-635 in detergents

Alkaline cellulase from Bacillus sp. KSM-635 (EC 3.2.1.4) had reproducible detergent effects on cotton cloth that was artificially or naturally soiled with oily and/or particulate matter, under European washing conditions. The detergent effects of the cellulase, in combination with surfactants, apparently were the result of enzymatic action on amorphous regions of cotton fibers in which soil was trapped. The contribution of cellulase to soil removal increased as (i) the amount of soil in the amorphous regions of fibers in test fabrics was increased and (ii) the inhibition, by soil that adhered to the fibers' surfaces, of the action of the cellulase on fibers was reduced. Alkaline cellulase had the potential to replace, in part, both surfactants and zeolite in detergents, and it reduced washing time and allowed washing at lower temperatures under European washing conditions. The marked detergent effect of cellulase on naturally soiled cotton fabric was visually apparent, and it inhibited the accumulation of ash, calcium, and other inorganic components on cotton fibers during wash-and-wear cycles. These contributions of cellulase to the cleanliness of cotton fabrics were clearly increased by repeated wash-and-wear cycles. Cotton fabrics were not degraded by washing with the cellulase because effective hydrolysis by the cellulase occurred only in the amorphous regions of cotton fibers.     

Application of statistical analysis to mixed soil detergency

In previous studies, statistical method using distribution of detergent power and that of resistance of soil against washing was applied to analyze detergency of oily soil and solid particle soil. In this paper, this method was applied to an analysis of detergency of mixed soil. Artificially soiled cloth prepared by aqueous dispersion method was used as a mixed soil sample. Four-time consecutive washing tests were conducted under the same washing condition in Terg-O-Tometer using two kinds of detergent solution and distilled water. Change of removal efficiencies due to repetitive washing was used to determine the two distributions. Result shows that detergent power can be expressed as cumulative distribution function. In washing simulation using the cumulative distribution functions, the predicted removal efficiencies corresponded with experimental values. Moreover, the effect of soil aging on distribution of soil resistance against washing was found to move the distribution curve toward high resistance. These results show that the method using two statistical distributions can be applied to the detergency of mixed soil.     

Soil removal in relation to total work input; a calorimetric approach for model wash systems

A simple, straightforward method, utilizing the concepts of classical adiabatic calorimetry, for direct measurement of total energy delivery to bench scale clothes washing systems is described. The results of such measurements can be expressed in conventional work units such as calories per unit weight or per unit area of fabric. Using this method, total energy input is measured and related to soil removal in model wash systems using a standard cotton soil cloth. The relationship between energy input and soil removal is considered for a number of situations involving variations in stroke rate, load weight and detergent concentration. Finally, these results are used to develop a modified definition of detergency which places the emphasis on the efficiency of mechanical energy utilization in a soil removal process.     

Test method utilizing dry natural dirt for evaluating laundry detergents

A laboratory test has been developed for screening detergent compositions with respect to the removal of natural dry particulate soil (dirt). The fabrics are soiled uniformly with dirt obtained from a suitable area and then laundered under controlled conditions in a Tergotometer. The total soil removal is determined instrumentally. The test enables the researcher to check the effects of many variables, such as temperature, water hardness, builders, fabric, etc., with a minimum amount of preparation and time. The soil removal data is analyzed by a suitable statistical method, and the results are good indicators of practical performance.     

The effect of sodium carboxymethyl cellulose on synthetic detergent systems

Summary Certain forms of sodium carboxymethyl cellulose have been shown to be highly effective as synthetic detergent promoters. Formulations containing a sodium alkyl aryl sulfonate type of synthetic detergent, alkaline salts and a type of sodium carboxymethyl cellulose developed for high detergency promoting properties surpass high quality fatty acid soaps in both carbon soil removal and whiteness retention on cottons. Methods having a relatively high order of precision for the evaluation of detergency have been presented in detail. By these methods two fundamental characteristics of detergency—as applied to the laundering of cotton fabrics may be independently measured.     

Detergency evaluation. III. Adjustment of Terg-O-Tometer and launderometer wash test methods to produce comparable soil removal data

Conclusions It was demonstrated that the average soil removal values for the four 10-minute wash Launderometer method could probably be essentially duplicated by a single 3-minute Terg-O-Tometer wash and one 2-minute rinse. The 3-minute Terg-O-Tometer method did not result in the same comparative rating of four detergents, but a series of tests with several other detergents using a 5-minute wash and a 5-minute rinse (using for comparison purposes a standard detergent) resulted in quite effective ratings. Of 13 detergents tested over a period of time, the two test methods provided soil removal values identical within a 95% confidence limit. These data indicate that a satisfactory technique can be developed using the Terg-O-Tometer, which would provide soil removal values and ratings of detergents closely paralleling the results obtained by the Launderometer multiple-wash method.     

The effect of surfactant structure on the rate of oil solubilization into aqueous surfactant solutions

Reduced washing temperatures decrease the rate of the various processes in a laundry cleaning cycle. This implies that fast acting detergents are needed if acceptable washing performance is to be maintained within a realistic period of time. An important factor is the rate of oily soil removal which, among other things, is a function of the molecular structure of the surfactants used in the detergent. To support the selection of proper surfactants we have established relationships between chemical structure and rate of oil solubilization for a series of alkylarenesulfonates with various alkyl chain lengths, points of attachment of the phenyl group at the alkyl chain, and aromatic substitution patterns. It is shown that oil solubilization kinetics are very sensitive to the geometry of the surfactant structure: for a set of isomeric alkylarenesulfonates the rate of oil solubilization can be made to by more than an order of magnitude by changing the substitution pattern around the aromatic ring. The results offer a predictive tool for the design of molecules with the proper surface activity under a wide set of experimental conditions. Presented at the joint AOCS-Japan Oil Chemists’ Society meeting in Honolulu, Hawaii, in May 1986.     

A natural soil and mechanism of removal

Nitrogen compounds in natural soils are studied in relation to their effect on the soil removal mechanism in detergency. Nitrogen compounds in various forms and in fairly large amts are found in natural soils, and more than 24% of these nitrogen compounds are presumed to be high mol wt nitrogen compounds or proteins. These high mol wt nitrogen compounds which cannot be removed by water can be removed by the detergent action of sodium dodecyl benzene sulfonate (DBS). When the detergency of DBS was compared with nonyl phenol-polyoxyethylene adduct, the detergency for artificial soil cloths did not coincide with results obtained with naturally soiled cloths. These data suggest that some interaction between DBS and nitrogen compounds might have contributed to the detergent action. If proteins were added to the present artificial soil formulation, better correlation might be expected between artificial and natural soil detergency results in DBS evaluation.     

Heavy-duty liquid detergent

A highly concentrated liquid detergent was developed. For the consumer, the quality and costs of this detergent correspond to the light-duty washing powders, The new detergent can be used in washing machines as well as for hand-washing. For the consumer, the liquid product is ready for immediate use, gives no solubility problems in hte washing bath and saves both time and energy by surfactants and containing an enzyme, the liquid detergent is activated for strain removal. It is recommended especially for such strains as collar soil, blood, grass and many kinds of food strains. For the best result, the instruction advises the application of "Flytande Tvättmedel" directly on visible stains in a prespotting fashion.     

Removal of fatty soils from cotton in aqueous detergent systems

A gravimetric method for studying the factors involved in removing fatty soils from cotton in aqueous detergent systems is described, and comparative data are given for removal of lanolin, lard, sebum, and hydrocarbon soils from cotton. Comparisons are made for a number of surfactants used in detergent formulations and effects of various builders are noted. Effects of some of the parameters of the wash bath such as detergent concentration, water temperature, and wash time are discussed. It is thereby demonstrated that:

1. 1.
   Maximum fatty soil removal is attained from cotton in 5 min or less at 120F with 0.25% of a good detergent.     
   
   

Detergency measurement using artificially-soiled cloths

Summary and Conclusions Four types of artificially-soiled cloths are compared in their ability to evaluate cleaning of representative detergent products. Three of these cloths are commercially available while the fourth is from a private laboratory. These are compared in their ability to rate detergents in the same order as naturally-soiled clothes rate detergents. Sensitivity and reproducibility of the various soiled cloths in measurement of soil removal and whiteness retention are studied. Results show that artificially-soiled cloths must be used advisedly. There is no substitute for actual performance tests of detergent products under practical conditions. At best, artificially-soiled cloths are useful for “screening” purposes where positive test results are confirmed by practical tests. Presented at the 25th annual fall meeting, American Oil Chemists’ Society, Chicago, Ill., October 8–10, 1951.     

诺维信酶制剂在无磷洗衣粉中的应用研究(Ⅰ)

研究考察了3种诺维信洗涤用酶制剂(Sav4.0T,Sav/Term4.8/12T,Sav/Term/Cell7.2/24/0.14T)对4种市售无磷洗衣粉(A ,B ,C ,D)和一种皂粉(E)去污力性能影响的一些实验及讨论。实验以试样对5种人工染污布的去污比值表征其初次去污力 ,以试样对5种人工染污布去污力的综合评价确定了诺维信3种酶制剂在无磷洗衣粉中的适用性及价值。而关于最新酶产品对无磷洗衣粉去污力的提高、抗再沉积性能的改善等作用将在续篇里做更详尽地讨论