Detergency

Theory and Technology

G. Cutler

• Publisher: CRC Press
• Year: 2020
• Print ISBN: 9780824775032
• eBook ISBN: 9781000146707
• Edition: 1
• Topic: Ciencias físicas
• Subtopic: Química

This volume provides an overview of the theory and practical aspects of the detersive process, detergency testing, analysis of detergents, and progress in formulating detergents. It discusses temperature effects and cold water cleaning only from the kinetic and mechanistic points of view.

1
Evaluation of Detergency

ERIK KISSA Jackson Laboratory, E. I. du Pont de Nemours & Company, Wilmington, Delaware

1. I. Introduction
2. II. Natural Soiling
3. III. Artificial Soils
   1. A. Problems and pitfalls
   2. B. Classification of soils
   3. C. Oily soils
   4. D. Fatty soils from skin
   5. E. Particulate soils
   6. F. Stains
4. IV. Artificial Soiling
   1. A. Soiling methods
   2. B. Direct application of liquid soil
   3. C. Direct application of particulate soil
   4. D. Transfer soiling
   5. E. Soiling of carpets
5. V. Test Fabrics
6. VI. Washing Methods
   1. A. Apparel fabrics
   2. B. Shampooing of carpets
7. VII. Soil Redeposition Tests
8. VIII. Determination of Soil
   1. A. Methods
   2. B. Visual estimation of soil
   3. C. Analytic methods
   4. D. Spectrophotometric methods
   5. E. Kubelka-Munk relationship
   6. F. Spectrophotometric determination of oily soils
   7. G. Kubelka-Munk relationship of particulate soils
   8. H. Other equations relating reflectances to soil content
9. IX. Conclusions
10. References

I. Introduction

Detergency can be defined as the removal of unwanted substances from a solid surface brought into contact with a liquid. The removal of these unwanted substances, called soils, from textiles depends on several factors, such as the detergent, mechanical action during washing, and the substrate. Accordingly, detergency testing is essential for the development of detergents, washing machines, textile fibers and textile finishes, and so on.

A detergent contains one or more surfactants formulated with other components to enhance detergency, reduce soil redeposition, and improve properties influencing the acceptance of the product by the consumer. The evaluation and testing of detergents involve chemical analyses, physical measurements, toxicological and ecological testing, and functional evaluation of the detergent. The functional evaluation of a detergent by washing textiles involves several processes: soil removal by detergency proper, which is opposed by soil redeposition, and soil destruction by bleaching or enzymatic degradation. All these processes must be considered when evaluating the efficiency of a detergent.

The methodology of evaluating the soil release performance of fabrics and finishes [1,2] is similar to testing detergents except for a different emphasis on the variables tested. Evaluating detergency for the purposes of improving the design of washing machines considers, in addition of soil removal efficacy, other factors, such as water consumption and energy input.

Detergency is tested by (1) applying representative soils to test fabrics or collecting naturally soiled textiles, (2) estimating the amount of soil on the fabric, (3) washing the soiled fabric under selected and controlled conditions, and (4) determining the soil remaining on the fabric [1,3]. This seemingly simple procedure is enormously complicated by the many variables involved: the composition and physical properties of soil, the soiling conditions, the construction and the chemical composition of the fabric, and the washing conditions, such as the time, temperature, detergent, and mechanical action [4]. Since it is not possible to examine all variables simultaneously in a single test, detergency tests are designed to simulate soiling and washing conditions of textiles in use. The variation of test conditions is usually limited to one variable, such as the detergent composition, or to several variables, by means of a statistical design [246].The main tasks of detergency evaluation are to define meaningful test conditions and develop procedures representing natural soiling and practical washing conditions.

II. Natural Soiling

Textiles or fabric samples used for detergency evaluation are soiled with natural soils deposited in actual use of the textile or with artificial soils applied in a laboratory. In the opinion of many deter gency experts [5—17], detergency testing with artificial soils in a laboratory is not a real substitute for evaluating the cleanliness of textiles after several soiling and washing cycles under conditions experienced by the typical consumer. The problem with this philosophy is the definition of the typical consumer and his or her laundering procedures [18].

The American Society for Testing and Materials has adopted a standard test [19], commonly referred to as the "bundle test." The test compares the cleanliness of matched loads of laundry during a series of at least 10 soiling and washing cycles. The families chosen to pa...

Table of contents

• Cover
• Half Title
• Series Page
• Title Page
• Copyright Page
• Preface
• Contributors
• Contents
• 1 Evaluation of Detergency
• 2 New Physical and Analytical Techniques in Detergency
• 3 Radioisotope Techniques in Detergency
• 4 Kinetics and Mechanisms of Soiling and Detergency
• 5 Soil Release
• 6 Inorganic Builders
• 7 Lime Soap Dispersants
• 8 Detergency in Nonaqueous Systems
• 9 Detergency Advances in Japan
• Author Index
• Subject Index