Computerization in fabric detergency testing

An automated method is described which greatly speeds the calculation of fabric detergency test results. Laboratory determination of fabric detergency commonly involves replicated, bench scale washing of small pieces of cotton artificially soiled with various oil-carbon black mixtures. Reflectance measurements before and after washing give a measure of the amount of soil removed. Often, in a program involving several variables, thousands of reflectance measurements may be involved. By converting the electrical signal from the reflectometer to digital form, and feeding this value to a card punch, the reflectance values are systematically recorded on punched cards. Using an appropriate computer program, the reflectance changes for each test are calculated and tabulated, the saving in operator time is large and statistical examination of the data can be incorporated with the program. An example of the type of data output is given. Presented at the AOCS-AACC Joint Meeting, Washington, D.C., March 1968.     

高效洗衣液的研究

以提高洗衣液的去污力为目标,通过调整阴离子表面活性剂和非离子表面活性剂之间的比例,设计配制了一系列的洗衣液样品,分别测定各种配方20℃时洗涤国标污布前后的表面反射率,从而得到相应的去污比。对照结果表明,当阴离子月E离子为2：1(质量比)时,其相应配方的去污力最强,低温洗涤效果最好。又从应用角度对其应用性能进行了评价,通过测定该配方的去污速度、洗涤效应和对有色织物的色牢度的破坏情况的考察,并与洗衣粉和标样作对比,进一步证明了该配方是洗衣液去污力的优化配方。     

An electrophoretic study of the detergency process

By using a micro-electrophoresis technique, the electrokinetic behavior of cotton and a clay soil was studied in various surfactant, tripolyphosphate, and carboxymethylcellulose solutions. Correlative soil-deposition studies were also made. Data are presented which show that doublelayer forces of repulsion are not of major importance in preventing the deposition of a clay soil on fabric. However a correlation was demonstrated between soil deposition and adsorption processes which occur at soil-solution and fabric-solution interfaces.     

荧光增白剂对洗衣粉白度与去污及织物增白的影响

研究了用于洗衣粉的主要类型增白剂对粉体白度、去污性能和织物增白3个方面的影响。结果表明,不同类型的增白剂对洗衣粉粉体白度、去污性能及织物增白作用的影响有较大差异,确定了不同增白剂的适宜使用量。     

Polyacrylamide-treated kaolin: A fabric study

Particle interactions, and in turn fabric, determine the behavior of clay mineral particle systems. Polymers with deliberately chosen characteristics, such as molecular mass and ionic type, can be utilized to manipulate clay fabric. The purpose of this study is to understand fabric development in a clay–polymer system, specifically kaolin–polyacrylamide systems over a wide range of solids content. Methodologies include sedimentation tests (low solids content), viscosity measurements (moderate solids content), and liquid limit measurements (high solids content), and are conducted to determine variation in fabric for kaolin–polyacrylamide systems at various concentrations, molecular mass and ionic types of polyacrylamide. Fabric development is verified using scanning electron microscopy (SEM). Results show that the polymer charge type impacts the resulting fabric formation only at polymer concentrations above a threshold concentration. Floc/aggregate size and density tend to increase with increasing polyacrylamide concentration, while high molecular-mass polyacrylamides tend to induce the formation of open flocculated structure. The most likely particle association in the presence of nonionic polyacrylamides is face-to-face association due to polymer bridging. A relationship is found between polymer characteristics, solids contents, and micro-scale particle arrangement. This study is relevant to the emerging field of engineered soil fabrics.     

Hard surface detergency

In a study of hard surface detergency using glyceryl trioleate, oleic acid, and octanoic acid soils with three types of anionic and three types of nonionic syndets, only potassium laurate showed maximum detergency at the CMC (critical micelle concentration), with the potassium laurateoctanoic acid system being an exception. In general glyceryl trioleate and oleic soil removal (180°F.) at the CMC was low, not over 40%; octanoic acid detergency at the CMC was substantially higher, 65 to 83%. Considerable differences in removal of the various soils by the same surfactants were found. A generalization was observed in the detergency of glyceryl trioleate soil—soil removal increased sharply on passing the CMC with increasing concentration until approximately 90% detergency was reached, at which point soil removal began to level off and approach 100% with a much smaller slope. Visual observations of the cleaning processes suggested a partial answer for the differences in soil removal. Removal or glyceryl trioleate soil by both anionic and nonionic syndets appeared to be due chiefly to a displacement action caused by preferential wetting of the basis metal. Removal of octanoic acid by the nonionic surfactants in a diffusing cloud of small particles seemed to be due to solubilization followed by emulsification and precipitation of the acid soil. Several relationships were discovered in two series of analogs (polyethenoxyethers of nonyl phenol and tridecyl alcohol). It was found that the ratio of the HLB (hydrophile-lipophile balance) values of two analogs was approximately equal to the fifth root of the ratio of their CMC values. The correlation held for analogs varying by as much as 15 moles ethylene oxide. A linear relationship was also found between HLB value and the reciprocal of the ethylene oxide mole ratio for the polyethenoxyethers of nonyl phenol.     

A motor oil soil for detergency testing

Bright Stock/Pale Oil (BS/PO) soil represents a typical motor oil soil, but it is more constant in composition than clean or dirty commercial motor oil. It does not require the addition of any dye, as is the case with mineral oil or cooking oil, and when applied to cloth, it produces very uniform soilings. The statistical reproducibility of detergency tests run with BS/PO is better than mineral oil and about as good as sebum.     

A method to improve reproducibility in detergency tests

Conclusions 1. A method for detergency tests has been described which, it is felt, yields a higher degree of reproducibility than the soiled fabric-Launderometer Method commonly employed. In terms of Standard Deviation, the reproducibility of a determination was found to be about ±0.7 when results were expressed as units of black removed, and under the conditions described in this paper. 2. This method makes it possible to determine with reasonable assurance differences between detergents which are greater than 6% (Detersive Efficiency). 3. The simplicity of apparatus required for the test should make it available for use in other laboratories. There is also the possibility that any type of standard soiled fabric could be used in the test, inasmuch as the manner of using the soiled fabric more than the manner of preparing it, largely determines the reproducibility of the method. (This point is at present under investigation.) 4. The method, it is thought, might be adapted to measure relative efficiencies of various types of washing machines, as well as for evaluating detergents.     

A double label radiotracer approach to detergency studies

The comparative detergency of a series of built detergents of commercial interest has been measured via the use of a doubly labeled multicomponent synthetic soil. Four test fabrics: cotton, nylon, Dacron, and Dacron/cotton were soiled with the seven-component soil, which was in turn almost completely and then individually labeled. The fabrics were washed in a conventional Tergotometer under cold-water and hot-water conditions. Analyses of the fabrics before and after washing were made by liquid scintillation counting. Two sets of experiments were run, the first based on cold-water detergent formulation (heavy-duty liquid), the second based on hot-water detergent formulation (heavy-duty powder). A number of nonionic surfactants were compared with linear alkyl aryl sulfonate in the first set, and two anionics were compared with two nonionics in the second set. Expressing results as total detergency, i.e., amount of soil removed from all four fabrics, it was found that, under cold-water conditions, LAS (average side chain C₁₃) is significantly less effective than the nonionics investigated. The linear primary alcohol (C₁₂-C₁₅ and C₁₄-C₁₅) ethoxylates removed slightly more soil than the ethoxylates of a Ziegler alcohol (C₁₄, C₁₆, C₁₈) and random secondary alcohols (C₁₁-C₁₅). The same tabulation for the heavy-duty powder formulations under hot-water conditions showed LAS to be least effective over-all, sulfated linear primary alcohol somewhat more effective, and ethoxylated linear, primary alcohol slightly more effective still. Redeposition of the various soil components onto unsoiled cotton was found to be slight, ranging from 0.2% to 1.7% of the amount in the wash water. Presented at the AOCS Meeting, Philadelphia, October 1966. US Testing Service, Hoboken, N. J.     

A triply labeled particulate soil for detergency studies

A kaolinite type of clay made radioactive by neutron irradiation (Spinks Bandy Black), described in an earlier report, has undergone extensive testing to determine its suitability as a particulate component of an artificial radioactive soil. The other components of the soil are labeled with¹⁴C and tritium. The incorporation of the radioactive clay into an established soil required the development of a reproducible padding procedure and the development of suitable analytical methods for the clay, as well as modification of the existing method for¹⁴C and tritium in the presence of the radioactive clay. A problem arose when it was noticed that, after the padding step, the specific activity of the clay adhering to the fabric was higher than the starting clay. This was traced to the fact that Spinks Bandy Black is not only a mixture of varying particle sizes, but of changing chemical composition with varying particle size. Thus, one could not readily convert radioactivity to weight. The problem has been resolved by resorting to chemical analysis for SiO₂ and Al₂O₃ of a few representative swatches from each padding run to give the weight of clay per swatch and thus the specific activity. Chemical and radiochemical analyses of the swatches after laundering have demonstrated that further disproportionation of the clay is minor. A large Terg-O-tometer washing study was made under a variety of conditions to determine the precision of the method for all three labeled components of the soil. It was found from sets of four replicates that the precision for clay detergency is ±2.5%; for the polar fatty soil detergency (¹⁴C) is ±2.3%; and for the nonpolar fatty soil detergency (tritium) is ±3.5%. Redeposition of the clay in the presence of a built detergent is usually less than 1%.     

A kinetic study of catalytic butane dehydrogenation

A study was made of the dehydrogenation of n-butane over a commercial chromia-alumina catalyst. Dehydrogenation runs were performed at 500°C. and space velocity of 34,000 hr^?1 over a range of butane partial pressures from 0.06 to 1.80 atm. Conversions were differential, averaging about 3% (with a maximum of 6% ) of the input butane. Reaction was found to be 0.75 order in butane partial pressure. Thermodynamic equilibrium was attained among the products, which were 1-butene, cis-2-butene, and trans-2-butene. The method of Yang and Hougen showed dehydrogenation to be surface reaction controlled at a confidence level of 91%. This conclusion agrees with that of a previous study by Dodd and Watson.     

A kinetic study of methane hydrate formation

The kinetics of methane hydrate formation, after commencement of nucleation, were studied using a semibatch stirred tank reactor. The temperatures studied in the experiments were from 274 to 284 K over a pressure range of 3–10 MPa. The results of the experiments revealed that the formation kinetics were dependent on the interfacial area, pressure, temperature and degree of supercooling. The history of water sample affected the induction delay times for nuclei formation, but it had no observable effects on the overall kinetics of hydrate formation after the nucleation had commenced. A consistent semi-empirical model was formulated to correlate the experimental kinetic data.     

Studies of soiling and detergency

A study was made of the desorption of carbon-14 labeled fatty acid, fatty alcohol, hydrocarbon, triglyceride, and hydrophobic and hydrophilic particulate carbon from cellulose, Nylon, and polyethylene terephthalate films into aqueous solutions of cationic, anionic, and nonionic deter-gents. Use of the polymers in film form as end-windows of a Geiger counter and labeling of the soils with radioactive carbon-14 allowed con-tinuous monitoring of the amount of sorbed material and normalized the usual complication of fiber and fabric geometry so that results ob-tained with different polymers could be directly compared. An excellent correlation was established be-tween fatty soil removal from polyethylene terephthalate film and fabric surfaces; thus re-sults obtained with film substrates have practical significance. Wash variables were carefully con-trolled and were altered one at a time to learn their effect on the soil-removal process. Results are discussed in terms of the possible mechanisms of soil removal.     

Studies in detergency correlation

In alkaline cleaning solutions of ca. pH 12 containing either a primary alcohol sulphate, a straight chain alkyl aryl sulphonate, or a fatty acid soap, detergent efficiency is increased synergistically by the addition of nonionic agents the HLB values of which lie within certain ranges. Those cleaners containing the anionic surfactant with the highest HLB exhibit the most synergism. In such cleaners, increasing detergency is directly related to increasing surface tension and critical micelle concentration of the unbuilt anionic surfactant, and to increasing surface tension of the nonionic surfactant. Asphalt soil removal, judged the resultant of the combined properties of penetrability, peptization, and wetting, was used to indicate detergent synergism in the aqueous alkaline cleaners studied.     

A laboratory method for testing laundry products for detergency

A laboratory screening test for fabric detergency has been developed, which closely parallels practical laundry operations. Natural airborne particulate is used so that the argument for and against carbon soil is eliminated. The oily soil consists of synthetic sebum, thereby simulating the surface film that covers the human integument. The particulate and fatty matter are combined into an aqueous suspension and padded onto the fabric. Variables can be measured in a minimum of time because the entire procedure is carried out in the laboratory and is not dependent on a panel of subjects as is the case in most practical testing. The procedure for this test as generally employed consists of multiple washes and measures brightener build up and redeposition in addition to detergency. Precision of the method is ± 0.4% at the 95% confidence level. Evaluations are made both visually and instrumentally.     

Further studies of detergency correlation

The significance of the relationships of the linearity constants of a previously reported detergency-micellar solubilization function (1) to surfactant HLB (hydrophile-lipophile balance), boundary tensions, and soil dipole moment was extended, first, by demonstrating their existence in systems of four homologous surfactants with one soil or four classes of soil with one surfactant, and second, by showing in every case that they are probably physical rather than random because they contain fewer constants than the number of points (four) used in their derivation. A study of a series of surfactant-soil systems consisting of a family of polyoxyethylated nonyl phenols and a family of saturated fatty acid soils (12–18 carbon) revealed linearity of the R-log (M/CMC) and surfactant HLB-log (M/CMC) functions for values of R (ethylene oxide mole ratio) between 15–50 and 10–100, respectively (M=surfactant concentration giving ca 100% removal of 16 and 18 carbon fatty acids, and CMC=critical micelle concentration). The validity of the semi-logarithmic functions was confirmed by the fact that they indicated linearity between R and surfactant HLB as previously reported (2). Abnormally high nonyl phenol adduct concentrations (2.7–3.8%) were required to give good fatty acid removal. It was suggested that the initial decrease in detergency with increase of fatty acid soil HLB from 6.5–9.8, followed by increasing detergency as the soil HLB continued to increase to 11.25, was due to differences in the relative magnitudes of the soilsubstrate adhesive forces and micellar solubilization existing in the soil HLB range. Sodium dodecyl benzene sulphonate was a good detergent of the saturated fatty acids, soil removal being independent of soil HLB for the 12–18 carbon acids. The fatty acid soaps were poor detergents of these soils. A “net ethylene oxide solubilizing power” method of computing HLB was proposed, based on known polar group hydrophobe-solubilizing values.