THE EFFECTS OP WATER TEMPERATURE AND

DETERGENTS ON SOIL REMOVAL

IN THE LAUNDERING OP

TEXTILES

by

LOUISE BENTLEY WOODPIN, B. S.

A THESIS

IN

HOME ECONOMICS

Submitted to the Graduate Faculty of Texas Tech University in Partial Fulfillment of the Requirements for

the Degree of

MASTER OP SCIENCE IN HOME ECONOMICS

Approved

Accepted

August, 1975

fli^Li.ji'h AC SOS T3

No. HO C,Cp. --- ACKNOWLEDGMENTS

The author wishes to express her appreciation to Dr.

R. G. Steadman for his guidsince, ideas, interest, and pa­

tience throughout this study.

Acknowledgments are also made to Dr. Norma Walker and

Dr. Delilah Roch for their words of encouragement through­

out the duration of the study.

Special thanks are owed to Mr. Bob Wyatt for his guidance,

understanding, and special Interest in helping with the taking

of the reflectance readings at the Textile Research Center.

ii

TABLE OP CONTENTS Page

ACKNOWLEDGMENTS 11

LIST OP TABLES V

LIST OP FIGURES Vll

Chapters

I. INTRODUCTION 1

Definition of Terms 3

Purpose of the Study 4

Limitations of the Study 6

II. REVIEW OP LITERATURE 8

Cotton 8

Synthetics • • . . 10

Purpose of Laundering 11

Steps in Laundering. • • . . 13

Detergents 14

Component Parts of Detergents 19

Using Soaps and Synthetic Detergents . . . 22

Quantity of Detergent Needed 23

The Effects of Temperature on Soil Removal 2k

The Effect of Bleaches on Soil Removal . . 26

III. PROCEDURE 28

Launder-Ometer 28

Color Eye 29

iii

Phase 1 30

Phase II 3^

IV, FINDINGS AND INTERPRETATIONS 36

Phase 1 36

Phase II 48

Cost-Benefit Analysis 64

V. CONCLUSIONS 70

LIST OP REFERENCES 71

iv

LIST OP TABLES Page

1. Phase I Tests on 50/50 Cotton/Polyester Blend. 31

2. Reflectance of 50/50 Cotton/Polyester Blend Soiled Fabrics 37

3. Reflectance of 50/50 Cotton/Polyester Blend White Fabrics 39

4. Mean Reflectance of Soiled 50/50 Cotton/ Polyester Blend , . 40

5. Phase I Analysis of Variance: Both Types of

Detergents Included , 41

6. Critical P Values 43

7. Significant Differences in Reflectance of Pre-Soiled Fabrics 44

8. Significant Differences in Reflectance of White Fabrics 46

9. Analysis of Variance: Reflectance of Soiled Cotton 50

10. Significant Differences in Reflectance of Pre-Soiled Cotton Fabric 51

11. Analysis of Variance: Reflectance of White Cotton 53

12. Significant Differences in Reflectance of White Cotton 54

13. Analysis of Variance: Reflectance of Soiled Polyester • • 57

14. Significant Differences in Reflectance of Pre-Soiled Polyester Fabrics 58

15. Analysis of Variance: Reflectance of White Polyester 61

16, Significant Differences in Reflectance of White Polyester 62

17. Cost Per Wash Load of Anionic and Non-ionic Detergents . • • • 65

vl

LIST OP FIGURES Page

1. Cost-Benefit Analysis of Cotton 67

2. Cost-Benefit Analysis of Dacron Polyester . . . 68

vii

CHAPTER I

INTRODUCTION

"The purpose of laundering is to remove soiling matter

from used textile articles, to refinlsh them to their orig­

inal shape and in good condition" (Panko, 1968, p. 5), In

principle this sounds fairly easy, but in practice it is

far more complicated. For example, not every type of fabric

can be laundered by the same process. Some textile fibers

can withstand high temperatures in washing, but others, in-

eluding many of the newer fibers and finishes, require great­

ly lowered temperatures. In the cleansing of garments and

other items made of textiles, much depends on the ease with

which soiling matter is released during the cleansing pro­

cess. Ease in cleaning varies from fiber to fiber and can

be affected by the finish given to a fabric during manu­

facture.

Since synthetic fibers have become increasingly pop­

ular in the last few years, the homemaker needs to know how

to cleanse effectively the new fiber. Manufacturers sug­

gest warm water for the synthetic fiber to avoid shrinking

and wrinkling. This causes a problem of major concern to

many consumers because the synthetic fabrics are not being

completely cleansed in the laundering process. Laundry

tests conducted by the United States Department of

2

Agriculture Indicate that if the temperature of the washing

solution is raised, the efficiency of the washing process

will be improved (Gibbons, 1972, p, 7^). Synthetics pose

an acute problem of which many homemakers are unaware. The

problem, peculiar to synthetic fibers, is that polyester

and others have an affinity for fats and oils (Holker, 1968,

p. 22), Synthetics attract fine ash, clay, and chalk and

hold them tenaciously when they are deposited in a dry state.

Soot particles strengthen the dirt»s adhesion, then soiling

matter is efficiently trapped by a film of body fat which

quickly accumulates on the garment and then is forced into

the fabrics by persistent rubbing (Holker, 1968, p. 23).

Many times the layer of dirt penetrates so deeply that it

is extremely difficult to remove. Static electricity, which

is generally a greater problem with synthetic fibers than

with natural fibers, attracts and holds soil particles on

a garment; this is another reason why an effective detergent

is required.

Laundering various articles together often causes an­

other problem for the already troubled homemaker—the prob­

lem of redeposition. Soil redeposition is essentially a

form of greasy soiling that may occur when different dirty

fabrics are laundered together under certain conditions

(Holker, 1968, p. 23). Many times the dirty articles be­

come clean, and then become soiled again by redeposition.

Choosing the correct detergent and water temperature

to cleanse the fibers effectively without shrinking or

3

causing excess wrinkling in synthetic articles creates a

serious dilemma for the consumer. What is the consumer to

do with an ordinary wash to achieve the maximum cleanliness?

This study is designed to examine numerous assumptions held

by homemakers concerning the laundering of synthetics.

Definition of Terms

The following are definitions of basic terms related

to the study (Changing Times. 1972, p. 37):

Detergent—an agent (or solvent) used for cleansing

fabrics. Technically, soap is a detergent, but the term

detergent is popularly used to distinguish synthetic deter­

gents from soaps.

Soaps—a biodegradable substance; a surface-active

agent that foams, removes soil from surfaces, and keeps

dirt suspended in the solution. Laundry soap is made es­

sentially from animal fat (tallow) and alkali.

Phosphate detergent—a biodegradable chemical formu­

lation that includes a synthetic surface-active agent plus

a substance called a builder (phosphate). Phosphate in­

creases the cleansing action of the formulation, softens

water by counteracting such objectionable minerals as iron,

magnesium, and calcium, suspends soil, and keeps soil from

redepositing Itself on fabrics. Phosphates also emulsify

oily and greasy soils and reduces germs on fabrics and in

washing water.

Non-phosphate detergent—a biodegradable detergent in

which phosphate builders have been completely replaced by

other substances (in most cases, silicates and/or carbon­

ates ) •

Soiling—the uptake of fine particles of dirt and

grease largely at the fiber surface.

Redeposition—the redepositing of a fairly uniform

film of dirt on clothes during the laundry process.

g/1—grams per liter

M,S,D,—minimum significant difference at the 5% level

N,S.—not significant at the 5% level

0,W,P,—based on the weight of the fabric

•—significant at the 5% level

*»—significant at the 1% level

««»—significant at the O.IJJ level

Purpose of the Study

The purpose of the study was threefold: first, to

learn to cleanse textiles; second, to evaluate claims made

by laundry agencies and detergent mauiufacturers concerning

cleansing of synthetic and cotton fibers in warm water or

by the use of gentle treatment; and third, to determine the

most efficient cost-benefit ratio for cleaning textiles.

Unfortunately, fibers do not seem to be adequately cleansed

with the use of low wash temperatures and cold rinses.

Homemakers need and want to know how to cleanse the new

fabrics which have been made so readily available.

5

The variables included water temperature, type of deter­

gent, concentration of detergent, type of fabrics, and use

of bleach. The water temperatures tested were 150®P, 120°P,

and 90°P. The detergents tested were anionic and non-ionic.

The concentrations of detergents corresponded to the recom­

mended amount, over use, and under use of the detergent.

The fabrics used in the study were lOOJt cotton, lOOjK Dacron

polyester, and a 50/50 cotton/polyester blend. The last

variable studied was the effect of bleach on synthetics,

50/50 cotton/polyester blends, and cotton fibers. The study

by Hunter (I968, p. 364) indicated that bleach will not dam­

age synthetics, but it is not readily used on new fabrics.

The results of the tests on synthetic fabrics and the

detergent concentrations were the most important since very

little information is available on the cleansing process.

The study was divided into two parts. The hypotheses

for Phase I of the study were as follows:

The laundering performance of a 50/50 cotton/polyester

blend will not be affected by:

1. Type of detergent

a. Anionic

b, Non-ionic

2, Detergent Concentration (grams per liter)

a. Over use (2)

b. Under use (2/3)

3- Washing Temperature (®P)

a, 150

b. 120

c. 90

4, Use of an oxidizing bleach.

The null hypotheses for Phase II of the study were

as follows:

The performance in the laundering of 100Jf cotton and

100:{ Dacron polyester will not be affected by:

1, Type of Detergent

a. Anionic

b. Non-ionic

2, Detergent Concentration (grams per liter)

a. Over use (2)

b. Recommended amount (1 1/3)

c. Under use (2/3)

3, Washing Temperature (®P)

a, 160

b, 120

c, 90

Limitations of the Study

Some of the major limitations were as follows: The

Launder-Ometer was used instead of the washing machine,

because it greatly improved the reproducibility of the

study. The machine made the study economically feasible,

by enabling up to twenty tests to be run simultaneously,

but this did remove the experiment from the "home" to the

"laboratory", A limitation was the use of the fabric

7

specimens rather than garments. This limited the kinds of

soil and the number of fabrics which could be used. Com­

mercially pre-soiled fabrics were purchased from United

States Testing Company, Inc, for the study, not fabrics that

had been soiled from wear. These fabrics were much dirtier

than most clothes because they were not soiled from actual

wear. The fabrics used were white rather than the many dif­

ferent colors as seen in the home, but the white fabrics

seem to be the object of most laundering problems. Another

reason for using white fabrics was that dyes often cause

color distortion in testing rather than indicating a lack

of cleanliness of the clothes.

The detergents selected were representative of the

anionic and non-ionic detergents normally used in the home.

Testing of all available types of detergents was not feas­

ible for the study.

The fabric specimens were representative of fabrics on

the market today. Fibers representated were lOOJt cotton,

100JC Dacron polyester, and 50/50 cotton/polyester blend.

The size of the specimens also limited the study because

they were 3" diameter circles instead of garments. The in­

strument used to measure the reflectance or "cleanliness"

of the fabrics was a standard instrument rather than the

human eye, making the experiment more precise.

CHAPTER II

REVIEW OP LITERATURE

It is widely accepted that many modern synthetic

fabrics do not perform as well as desired in home laundering

(Hunter, I968, p. 362). The standards for laundry perform­

ance of synthetic fabrics have been revised as these fibers

have become more common and as criteria for cleaning other

fibers grow increasingly higher. The chemical makeup of

soils and the rate at which the soils are suspended and

are removed from fabrics in the laundry process are problems

now being considered (Port, Billlca, Grindstaff, 1968, p.

354). Research into these problems must take into account

the chemical and physical properties of each fiber, since

methods of soil removal vary with the fibers.

Cotton

Cotton has been used in the construction of textiles

since about 3000 B.C. It is still one of the most widely

used of all textile fibers (Jones, 1968, p. 1). Cotton is

particularly noted for its relatively high wet strength.

It is one of the principle fibers used today which is strong­

er wet than dry. Cotton fibers are receptive to dyes and

chemical finishes such as those which produce the easy-care

and no-iron properties (Jones, 1968, p. 2). Additional

8

9

comfort and appearance can be achieved when cotton is blend­

ed with synthetic fibers. The most usual example is the

polyester/cotton blends for shirting and sheets in which

the synthetic components improve the overall wear, perform­

ance, and durability (Jones, 1968, p. 2).

Cotton is still used in a wide variety of textile pro­

ducts which serve as apparel, household and industrial

fabrics. The use of cotton in apparel and household fabric

fields has been enhanced by developments in dyes and chem­

ical finishes. The developments have kept the use of cot­

ton from rapidly decreasing in spite of the competition of

the tougher synthetic fibers. Thus, one of the oldest

fibers remains eminently suitable for many end-uses — large­

ly because of permanent chemical modifications brought about

by man (Jones, 1968, p. 4).

Cotton is the whitest and cleanest natural fiber. It

can be laundered easily for it withstands high temperatures

well (boiling water does not hurt the fiber), and it can be

ironed with a moderately hot iron because it does not scorch

easily. Mildly alkaline substances such as ammonia, borax,

sodium silicate, sodium tripolyphosphate, and cold dilute

bleaching agente such as hypochlorites and chlorine bleach,

are not unduly detrimental to the fiber. Bleaching agents

must be used only under controlled conditions, since too

high concentrations destroy the fiber (Wingate, 1970, p.

230). Cotton is subject to molding caused by mildew, which

10

is a parasitic fungus. Warmth and dampness further the

growth of mildew.

Synthetics

Polyester»s growth rate has surpassed that of both

acrylics and polyamides to such a degree that by the end of

1974, more than 2.8 billion pounds of polyester fiber per

year were produced in the United States (Textile Organon.

1975)- Through the success of the durable press concept

at the consumer's level, the word polyester has become

synonymous with "ease of care" and "high performance" (Bum-

thall & Lomartlre, 1970, p. I8). Polyester fabrics have

many advantages over other fabrics such as wrinkle resis­

tance, resilience, washability, quick drying, dimensional

stability, and ease of care. Along with the advantages of

polyester, there are also disadvantages or problem areas,

with the major ones being soil redeposition and stain re-

mov€Ll (Burnthall & Lomartlre, 1970, p. 18). Although soil

redeposition has been reduced to some degree by finishes,

it still remains an area in which polyester needs improve­

ment.

Associated with soil redeposition is stain removal.

Polyester has a tendency to hang on tenaciously to oily

soils or oil-base stains. Again, finishing has in some

measure improved the overall performance of synthetic fibers

However, the fiber's basic affinity for oil-based stains

remains (Burnthall & Lomartlre, 1970, p. 20).

11

The process of producing polyester fibers is an in­

tricate one. The basic raw materials from which this fiber

is derived are coal, air, water, and petroleum. The chem­

icals (dimethyl terephthalate and ethylene glycol) derived

from these sources are processed in a vacuum at a very high

temperature until they form a solid, hard, porcelain-like

substance that has been melted into a honey-like liquid and

then extruded through a spinneret (melt spun). Filaments

are cooled and solidified. The dravJing and stretching of

these filaments to many times their original length gives

strength and elasticity to each filament (Wingate, 1970,

p. 369).

Polyester fibers are truly automatic wash-and-wear.

The fiber possesses excellent wrinkle resistance, has out­

standing stability after repeated laundering, can be heat

set to control shrinkage and sagging of the fabric, and can

be made permanently pleated. Polyesters are less damaged

by sunlight and weather and are not attacked by moths and

mildew. When dyes and finishes are properly selected and

applied, fabrics possess a low degree of flammability

(Wingate, 1970, p. 371).

Purpose of Laundering

Keeping clean is an old problem, and soiling and deter-

gency are much studied subjects. Yet, there are still un­

answered questions. How does the chemical makeup of soiled

substrate surface affect the nature of the soil which de-

12

posits on it and the rate at which this soil is removed

in a detergency process? Laundering is a necessity for the

purpose of cleanliness or hygiene, but it is also equally

important because of appearance. It is not enough that

textiles should be free from soiling and contamination after

washing, but they should be restored to as near new condition

as possible with no unnecessary wear, chemical change, or

alteration in appearance and feel (Perdue, 1966, p. 1).

Cleaning of fabrics is usually a more technical and

more involved process than either storing or refreshing.

It involves both over-all cleaning and spot removal. Wash­

ing may be either by hand or machine, but for either process

there are variations in the water temperature, the nature

of the detergent used, the use of bleach, the length of

sudsing time, and the method of moisture removal.

Most laundering today is done by the approximately 45

million home washing machines in use in the United States

(Wingate, 1970, p. 392). The main purposes of laundering

are to: (1) remove local and general soiling; (2) remove

stains; (3) maintain the whiteness or color in dyed and

printed goods; (4) keep or restore the original character­

istics; and (5) avoid chemical or physical damage which

will unnecessarily shorten the life of the fabric (Perdue,

1966, p. 1). In most cases, the removal of dirt and soiled

matter is not difficult, but there are exceptions. Very

heavy soiling may require drastic or prolonged washes,

which can have an adverse effect on the fabric.

13

Steps in Laundering

The essential steps in cleaning soiled fabrics are:

first, wetting the fabric and the dirt; second, removing

dirt from the fabric; and last, holding the removed dirt

in suspension, keeping it from redepositing on the fabrics

until it is rinsed away (Soaps and Detergents. 1967, p. 2).

Water alone has limited cleansing abilities. A soap or

synthetic detergent is needed to increase both the wetting

and suspending power of the water. When the soiled fabric

is agitated during the washing process, oily soil is broken

into small particles and surrounded by a film of detergent

solution. As the soil is lifted from the fabric, the soap

or detergent solution holds it suspended in the water and

helps the soil from settling back onto the clothes (Soaps

and Detergents. 1967, p. 3).

The laundering process is also necesssu'y to help pre­

vent the spread of bacteria in freshly washed clothes and

household textiles (Sanitation. 1971, P- 3). Neither the

water temperature nor the detergent used under today's

home laundering processes can be relied on to reduce to a

safe level the concentration of bacteria in fabrics.

Formerly, many consumers boiled their clothes, es­

pecially if there was sickness in the family. As long as

laundry was boiled, heat destroyed bacteria, sanitizing as

well as cleaning the clothes (Sanitation, 1971, p. 3).

Many bacteria, of course, aire released from fabrics during

washing and go down the drain with wash and rinse water.

14

Unfortunately, many others stay on the fabric and many

cause disease.

Both time and temperature are important in killing

bacteria. It takes three to five minutes of 212*P (boil­

ing) water to kill staphylococcus germs, or twenty minutes

at a washing temperature of 140®P (Witt & Warden, 1971, p.

iSl). The temperature of "hot water" used in home launder­

ing is often less than 140®P, and the wash cycle is not

twenty minutes (Witt & Warden, 1971, p. I8l). Some fabrics

may contain large numbers of bacteria when they go into

dryers. Drying cannot kill all bacteria, but it does re­

duce the bacteria count.

Detergents

(Cleaning Agents)

The home launderer has the problem of deciding whether

she should use a soap detergent or synthetic detergent.

Soap detergents are by far the oldest in use. In fact,

synthetic detergents have come into general use only since

World War II.

Soap is the result of a reaction between caustic alkali

and fat. There are pure milk soaps, which are all soap with

nothing added, and heavy-duty, all purpose built soaps.

Heavy-duty soaps have alkaline substances added to improve

the cleansing power.

Synthetic detergents are organic chemicals, the pre­

paration of which is complicated because of the nature of

15

the process involved. Although there are a number of chem­

ical types of synthetic detergents, a common one consists

of fatty alcohol sulfonates (Wingate, I97O, p. 398).

There are several types of synthetic detergents. First,

there are light-duty mild synthetic detergents for hand

sheers and nonfast colors and for machine washing lightly-

soiled articles and delicate fabrics. Second, there are

heavy-duty synthetic detergents with builders for improved

cleansing power plus a suds-making ingredient, intended

primarily for badly soiled and greasy articles washed in

top-loading automatic washers.

Synthetic detergents enter the market in two forms.

They may be supplied in an unmixed form, or they may be

mixed with alkalies and other substances to give a complete

detergent (Perdue, 1966, p. 208). Unmixed products may be

regarded as corresponding to soap insofar as they normally

require the addition of alkali and possibly other substances

when they are used in a wash. Two main differences between

soaps and detergents are that detergents are not neutralized

and do not give precipitates in the presence of hard water

or acids (Perdue, I966, p. 208).

The properties of detergents depend upon their chemical

composition. Detergents are made from petroleum, natural

fats, and oils. The chemical process that produces detergents

is more complex than the reaction between fat and lye which

makes soap (Laundry Book. 1972, p. 13). Because of a great­

er diversity of raw materials and chemicals, a greater

16

variety of processes are used in making detergents th£m in

making soaps. Detergents dissolve readily in water—hot,

warm, cold, soft, or hard (Soaps and Detergents. 1967, p.

3), and they do not form a scum in hard water. Although

some detergents form suds easily, others have similar cleans­

ing ability with little or no suds.

Detergents are also marketed as light-duty and heavy-

duty. Light-duty detergents are suitable for washing light­

ly soiled delicate fabrics. Because these detergents are

non-alkaline, they are safe for dyed fabrics and for acetate,

silk, and wool (Soaps and Detergents. 1967, p. 4). Some

examples of light-duty detergents are: Chiffon, Dreft,

Gentle Pels, Ivory, Joy, Lux, Octagon, Swan, Thrill, Vel,

Dove, and Palmolive.

Heavy-duty detergents are the workhorse products for

family uses. They have largely replaced soaps because they

do not react with hard water and cause scum (Soaps and Deter­

gents 1967, p. 4). They are more effective than light-

duty detergents for cleaning moderately to heavily-soiled

fabrics. They can be used safely on many fine fabrics and

are needed for thorough washing of fine fabrics that are

heavily soiled. Both high sudsing and low sudsing heavy-

duty detergents are available. Low-sudsing detergents are

designed for use in automatic washers because high sudsing

interferes with the mechanical action (Soaps and Detergents.

1967, p. 4). Heavy-duty detergents especially made for use

in cold water are available also and are suitable for wash-

17

ing lightly-soiled fabrics. Some of the major types of

heavy-duty high sudsing detergents are: Bold, Breeze, Cheer,

Pab, Oxydol, Tide, Wisk, Cold Power, Cold Water Surf, Duz,

and Surf. Some examples of low sudsing, heavy-duty deter­

gents are: All, Salvo, Whirlpool, Kenmore, Dash, and Cold

Water All (Soaps and Detergents. 1967, p. 4),

Detergents are also classified as anionic, non-ionic,

catlonic, SLnd amphoteric (Levitt, 1967, p. 54), An esti­

mated Sl% of today's comsumers purchase anionic-phosphate

detergents (Sears, 1970, p. 25). The majority of synthetic

detergents now available resemble soap in being anionic.

The anionic compounds form positively-charged ions which

contain the oil-soluble portion of the molecule (Perdue, 1967,

p, 208). The water solution carries the positive charge.

Anionic detergents are sodium sulphates or sulphonates or

organic substances. The term "S.P.A." is still used loosely

to cover synthetic detergents in general, but strictly it

stands for one particular type of anionic detergent—sul-

phonated fatty alcohol (Perdue, 1967, p. 208). Although

anionic synthetic detergents are not precipitated by acids,

they require at least mildly alkaline conditions if they

are to wash well,

A few of the synthetic detergents on the market are

not salts and do not split up into ions when they dissolve

In water. These detergents are called non-ionic. The lack

of ionization means that they are comparatively unreactive

and are compatible with many other substances. Although

18

they do not ionize, they require a hydrophllic component.

They are not precipitated nor do they lose much of their

washing power in neutral or acid conditions as do anionic

synthetic detergents (Levitt, I967, p. 62). The oil-soluble

portion may be derived from fatty acids, alcohol, amides, or

amines. As a rule, none of these detergents produces copious

suds. They are good cleaners and emulsifiers. The penetrat­

ing and solubilizing power of non-ionic detergents is said

to be significantly greater than that of their ionic counter­

parts (Fort, Billlca, & Grindstaff, I968, p. 36I). The pen­

etrating and solubilizing power of non-ionic detergents re­

sults from their uncharged nature. The non-ionic detergent

penetrates to such an extent that the oils are made water

soluble and the detergents act as a co-solvent. The non-

ionic synthetic detergents tend to clean synthetics much

better than the anionic detergents because of the penetrat­

ing power of non-ionics.

The non-ionic synthetic detergents comprise 25% of all

detergent products. Although the non-ionic only account

for 5Jt of all detergents sold, about 20J5 sire marketed for

industrial uses. One non-ionic detergent. All, is the se-

ond largest selling detergent^ comprising 7% of the total

sales (Sears, 1970, p. 31).

Catlonic synthetic detergents ionize as "invert soaps";

that is, the oil-soluble portion of the substance is posi­

tively charged. This synthetic detergent is mostly used as

19

fabric softeners. The detergent is based on stearic acids

or tallow (Levitt, 1967, p. 61).

The last type of detergent is the amphoteric. This

detergent acts as both catlonic and anionic and is most

widely used as wash-cycle softeners.

One basic disadvantage of all of these products is that

they were formulated with ingredients best suited for wash­

ing cotton (Davis, 1969, p. 525). If used in sufficient

concentration, these products do an acceptable Job of wash­

ing polyester/cotton blends. However, there are two draw­

backs. The first is the apparent reluctance of some deter­

gent manufacturers to recommend proper washing concentrations.

The second draw-back concerns soil redeposition or whiteness

retention. This is the so called "tattle-tale gray". It is

caused by the inability of the detergent solution to hold in

suspension all of the dirt removed from the clothing. The

soil simply redeposits onto the cleaned garments. This is

the basic reason why very heavily-soiled garments should be

washed separately from those not so heavily-soiled.

Component Parts of Detergents

Soap and detergent mixes consist of many compounds.

Many compounds are added to make detergents more effective.

Surfactants are active ingredients in soaps and detergents

that change the surface properties of water, soil, and fabrics

so that dirt can be easily removed (Perdue, 1967, p. ^k).

Before I965, some surfactants which were widely used in

20

household detergents decomposed very slowly in sewage treat­

ment plants or surface waters. The term surfactants is a

oontraction of surface active agents, embracing synthetic

organic chemicals which assist in penetrating and wetting,

emulsifying, dispersing, solubilizing, foaming, washing, and

scouring (Perdue, 1967, p. 4),

Mildly alkaline phosphates are important ingredients

in heavy-duty soaps auid detergents. They act as water soft­

eners providing proper alkalinity for good cleaning, and they

help in dispersing and suspending soil. One disadvantage of

phosphates is that they may contribute to the growth of algae

when discharged into rivers and lakes. Other alkaline salts,

such as sodium carbonate and sodium silicates, also are used

as detergent builders. In heavy-duty detergents, sodium sil­

icate helps prevent damage to the metal parts of the washer

and water pipes (Soaps and Detergents. 1967, p. 7).

The typical laundry detergent formulations for anionic

detergents are as follows: 12-15! linear alkylate sulfonate,

2-3Jf foam stabilizer, 40-50JC polyphosphates, 4-6jt sodium

silicate, 0.5-lJC carboxymethyl cellulose, 0.3-7Jf optical

brightener, .01-.03JK perfume, and 0-135 anticake material.

The typical laundry detergent formulation for the non-ionic

detergent is as follows: 6-lOJf non-ionic surfactant, 4-6^

sodium silicate, 40-50J5 polyphosphates, 10-20$ sodium

sulfate, 0-10;J sodium carbonate, 0,5-1.5$ carboxymethyl

cellulose, 0,3-.7JK optical brightener, 0.01-.03$ perfume,

and 0-1:K anticake material (Davis, 1969, p. 525).

21

Optical brighteners are included in most soaps and

detergents. These compounds, when absorbed into fabrics

during washing, convert some of the visible ultraviolet

light in sunlight to visible blue light. The additional

blue light reflecting from the fabric counteracts yellowness

and makes the fabric appear whiter. Fabrics also appear

brighter, because the total amount of visible light is in­

creased. Brighteners vary in composition and in their ef­

fectiveness on various fabrics. Some brighteners work well

on cotton and rayon and others on nylon and other fabrics

(Soaps and Detergents» 1967, p. 7). Plnishes on fabrics

may reduce the effectiveness of brighteners. Chlorine

bleaches inactivate some brighteners in wash water. To

avoid this, one should add the soap or detergent mix to the

wash water first, allowing a few minutes for the brighteners

to be absorbed into the clothes before adding the chlorine

bleach.

Enzymes are large complex molecules which are members of

the protein family. They are formed within all living cells,

in man and other animals, in plants, in fungi, and even in

the simpliest single-cell mirco-organism. While modern

detergents are extremely efficient in removing many types

of soil from clothing and other fabrics, they have not been

able to remove stains fully caused by substances made up

largely of protein such as blood, milk, eggs, gravy, and

baby formulae (Perdue, 1966, p. 62). Protein molecules

tend to lock onto fabrics and, thus, resist the action of

22

detergents. The primary function of proteolyic enzymes in­

corporated into detergent mixes is to split protein molecules

into simplier substances which can be removed easily by other

components of detergents.

The idea of using enzymes to remove protein-based stains

was originally patented in Germany in 1913. Enzymes are

relatively new in the United States. In the washing solu­

tion of the typical American home laundry machine, the level

of active enzymes is approximately one part per million parts

of water (Jackson & Rogers, 1934, p. 26). This small quantity

is sufficient to remove protein stains from even heavily-

soiled clothing.

Using Soaps and Synthetic Detergents

Whether one uses a soap or synthetic detergent depends

partly on the hardness of the wash water. In soft or soften­

ed water, soap does an excellent cleaning Job and is eco­

nomical to use. Hard water wastes soap (because the soap

reacts with the "hardness minerals" such as calcium and

magnesium salts) and forms a scum. The scum sticks to

washer parts and settles on clothes in gray specks, which

are most difficult to remove (Soaps and Detergents. 1967,

p. 7).

Water can be softened by precipitating softeners such

as washing soda and Climaline. These are dissolved in the

wash water before adding soap. Non-precipitating softeners

such as Calgon and Oakite keep minerals in solution in a

23

form that the minerals cannot react with soap to form scum.

These softeners have the advantage of redlssolving soap scum

already on fabrics.

Quantity of Detergent Needed

The question of the amount of detergent to use is a

very Importemt one, especially since fabrics containing

polyester tend to become more readily soiled by redeposition

than other fabrics. The detergent quantity specified on

the containers is only an average value. This provides a

good starting point which is always subject to adjustment

due to the conditions of the laundry concerned.

The amount of soap or detergent needed for a wash de­

pends on many factors. Some of the most important are: (1)

wash capacity of the washer; (2) size of the load being

washed; (3) amount of soil on the clothes, particularly

greasy soil; (4) hardness of the water; and (5) type of

detergent being used. The quantity added at the beginning

of the wash should be sufficient to maintain a good lather

throughout the wash. If water is very hard or clothes are

heavily soiled, one needs to increase the amount of soap

or detergent used. With soap or a high sudsing detergent,

a good layer of suds should remain throughout the wash cycle

on top of the water. A lack of sudsing indicates insufficient

detergent. Low-sudsing detergents should form and maintain

a thin layer of suds. If the lather should drop during the

wash, more detergent should be added at once in order to

24

restore the cleansing and suspending power of the solu­

tion.

White or pastel polyester fabrics, in particular, exhibit

a great increase in grayness. Market research surveys sug­

gest that consumers tend to under use detergents, particularly

the high foaming types (Hunter, 1968, p. 362). Because of

the tendency to under use detergents, polyester fabrics gray

badly; this is one of the major reasons for the failure of

polyester to be cleaned as well as cotton. The suspending

power diminishes during the wash and consequently the dirt

redeposits as the lather fails. It is perhaps better to run

a new wash cycle than to continue the current wash, because

insufficient soap or detergent during laundering is a com­

mon cause of graying in clothes (Perdue, 1966, p. 64).

The Effect of Temperature on Soil Removal

To facilitate the loosening £ind removal of soil, deter­

gent is added to the water. When the eo'ticles are agitated,

the soil is emulsified or taken into suspension in the deter­

gent solution. If during the washing process the water temper­

ature of the solution is raised, the efficiency of the wash

will be improved due to the ingredients known as "builders"

in the detergent. Builders are more active at high temper­

atures than at low temperatures. Usually, therefore, the

higher the temperature, the better the cleansing efficiency

(Gibbons, 1972, p. 74).

Water temperatures for laundering various types of

fibers vary from cold to hot. "Cold" means the temperature

25

of the water from the cold tap; "warm" is controlled thermo­

statically and the temperature is approximately 100**P; and

"hot" is the temperature of the hot water supply which ranges

between 140®P to 160**P. The hotter the water, the more

thorough the cleaning, the quicker the wash, and the great­

er the whiteness and the destruction of bacteria. Non-cel-

lulosic man-made fibers should be washed in warm water and

occasionally cold water. They do not require high tempera­

tures to loosen dirt, and the celluloslc fibers are less

likely to be colorfast at high temperatures. High tempera­

tures cause the fiber to be much more likely to wrinkle,

which is particularly objectionable for wash-and-wear gar­

ments.

Washing with a water temperature of 120**P results in

Insufficient sanitizing and soil removal. The United States

Department of Agriculture recommends that water temperatures

of 140**F be used in home laundering; however, temperatures

high enough to destroy harmful micro-organisms are seldom

used in home laundry (Loeb & Pollard, 1970, p. 52).

A high temperature helps to dissolve powdered deter­

gents more rapidly. If soap flakes are added to cold water

in a washing machine, the washing process starts cold, and

the flakes are slow in dispersing and dissolving in the

water (Perdue, 1966, p. 28). Much of the washing cycle will

be wasted before the solution in contact with the clothes

is sufficiently concentrated to give good cleansing. A

study by hunter (1968, p. 362) indicated that after several

26

tests were run on synthetics with cold-water detergents,

the cold water did not directly account for the greater re­

deposition experienced with the polyester in a home process.

At first, it seemed a temperature of 140°P was sufficient

for cleansing; later, however, it was concluded that a

temperature of 150* ? was more efficient for soil removal.

Warm or hot water is also needed in the rinse cycle. Cold

water causes the detergent solution to Jell, even when the

solution is relatively dilute. The temperatures selected

for the wash cycle must be compromises—each one chosen to

give the best possible cleanliness by using the highest

temperature in which the article can be safely washed (Gib­

bons, 1972, p. 7^).

The Effect of Bleaches on Soil Removal

Considerable literature is available on bleaching as

it relates to the processing of cotton fibers, but there is

very little information on the effects of bleaching on syn­

thetic fibers. A study by Hunter (1968, p. 364) found that

polyester fabrics were, in general, the least adversely

affected by bleach at recommended levels of usage.

Bleaching agents are chemicals which either destroy

coloring matter or convert it into colorless substances.

There are two types: (1) oxdizing bleaches, which act in

a manner similar to that of sunlight, air, and moisture

and destroy the coloring matter; and (2) reducing bleaches,

which act by changing the color into colorless substances

27

(Jackson & Rogers, 1934, p. 25). The only reducing bleaches

easily available for household uses are the hydrosulphites

of sodium. The example of an oxidizing bleach is hydrogen

peroxide or sodium hypochlorite.

Bleaches should always be used in the presence of a

detergent in the wash water; when used without a detergent,

the fabrics tend to suffer 21Jt more strength loss than when

it was used with a detergent. Bleaching is potentially

dangerous to fabrics; for that reason, it is very important

that the directions are carried out under strict control.

Bleaching itself will not remove dirt (Loeb & Pollard, 1970,

p. 52). Bleaching for the production of good whiteness is

a complete misuse; the main function of bleaching is the re­

moval of those stains which are not removed by an ordinary

washing process but are amenable to bleaching (Perdue, 1966,

p. 67). The whitening effect that bleaching may have upon

fabrics should be looked on as a subsidiary function only to

improve the first-class whiteness already obtained by a

good wash.

CHAPTER III

PROCEDURE

One of the first steps in preparation for the experi­

ment was to determine which of the initial variables need­

ed to be tested and select instruments which would most

effectively cleanse the specimens and assess the results.

The variables to be tested were: type of detergent (anionic

and non-ionic), amount of detergent, water temperature, and

the use of bleach. After the variables were selected, there

was the problem of deciding what type of fabrics were to be

used. Laboratory pre-soiled test materials were purchased

from United States Testing Company, Inc. The standard

soiled fabrics were 50/50 cotton/polyester blend, lot num­

ber 680A; 100$ cotton, lot number 695; and 100$ Dacron

polyester, lot number 698.

The following is a brief description of the instruments

used to launder the specimens and assess the results:

Launder-Ometer

The Launder-Ometer, a standard laboratory machine used

by the American Association of Textile Chemists and Color-

ists, was used as the washing instrument. The apparatus

consists of a heavily constructed stainless steel tank sup­

ported upon a rigid angle-iron frame. Within the tank there

28

29

is a rotor that carries twenty stainless steel cylinders in

which the tests are run. The tank is half filled with water

of the appropriate water temperature to correspond with the

tests. The temperature of the water bath is thermostatically

controlled. The initial water temperature inside the cylin­

ders also can be controlled by the use of a pre-heating load­

ing table. The cylinders are clamped in the rotor within

the tank and rotated by a motor on the Launder-Ometer for a

specified time (AATCC Technical Manual. I960, p. 82).

Color Eye

The instrument used to measure color or the reflectance

of the fabric was the Color Eye developed by the Instrument

Development Laboratories, The instrument measures reflect­

ance, or the percentage of incident light reflected by a

specimen of fabric versus the "standard white".

Fabric specimens are cut into three-inch diameter

circles and placed in a compression-loaded specimen holder;

eightypounds of pressure are then placed on the fabric in

the holder. The pressure allows the operator to take con­

secutive readings of specimens, eliminating deviations from

specimen to specimen caused by wrinkles or unevenly distri­

buted tension. There is a piece of glass in front of the

pressure-loaded specimen holder to hold the specimen in

place. Behind the specimen is a piece of white fabric

covered with plastic to eliminate the accumulation of dirt,

and so that the black from the specimen holder will not

affect the reflectance reading of the specimen.

30

After the pressure has been applied, the specimen hold­

er is attached to the sphere of the Color Eye. The light

from within the sphere causes the specimen to become illum­

inated with white light. Measurements are made using the

iiyti filter which measures the lightness-brightness of the

specimen. Filters are used to absorb wave lengths of light

not directly related to the "Y" value of the instrument.

Phase I

Phase I served as an exploratory step in the study of

the cleansing of textiles. The fabric used was 50/50 cotton/

polyester blend. The purpose of Phase I was to eliminate

any unnecessary variables and to refine the research process.

A Latin square design, which gives a random combination of

the variables, was used to enable the researcher to select

which variables were to be tested in Phase I of the study.

By using the Launder-Ometer, the amount of fabric and

wash liquor could be scaled down 300 times, thus saving time

and money. Instead of the 18-20 gallons of water, which

the washing machine requires to do a normal wash, the cylin­

ders which fit in the Launder-Ometer held 250 milliliters

of distilled water per wash experiment. The amount of

detergent used was 1 1/3 grams per liter per wash instead

of the recommended amount of detergent which is as much as

1 1/2 cups, depending on the type of detergent for a stan­

dard wash load in an automatic washer. The over use of

detergent concentration was 2 grams per liter and the under

use was 2/3 greims per liter.

31

The size of the wash load was decreased from a normal

load of 10 pounds to 13 grams per wash. The greatest sav­

in g in scaling down the experiment was in the amount of

fabric needed for the specimens and in being able to run

twenty different test simultaneously in the Launder-Ometer.

The set of tests run for Phase I of the study on the

50/50 cotton/polyester is shown in Table 1.

The type of detergent used for Phase I of the study was

Oxydol which represented the high sudsing or anionic deter­

gent, and an AATCC test detergent for the low sudsing non-

ionic detergent.

TABLE 1

PHASE I TESTS ON 50/50 COTTON/POLYESTER BLEND

Anionic Temp. («P)

150

150

120

120

90

90

Detergent Concen. (g/1)

2

2/3

2

2/3

2

2/3

Bleach (g/1)

0

0

5

0

0

5

Non-ionic Temp. ( P)

150

150

120

120

90

90

Detergent Concen. (g/1)

2

2/3

2

2/3

2

2/3

Bleach (g/1)

5

5

0

5

5

0

The procedure followed for the previously mentioned

tests was: the standard soiled fabric of a 50/50 cotton/

polyester blend was cut into twenty-four three inch

32

diameter circles and numbered to correspond to the appropriate

tests. These fabrics were washed together with clean white

fabrics of the same fiber content and of the same size to

determine whether the white fabrics were affected by the

soiled specimens during the washing process. The test fabrics

consisted of one gram (two circles) of pre-soiled test fab­

ric, one gram (two circles) of white fabric, and eleven grams

of white fabric as a dummy load. The dummy load consisted

of white fabric of the same fiber content as the pre-soiled

specimens and was cut into specimens similar in size to the

test fabrics in order to allow for agitation.

After the desired specimens were cut and identified,

selected specimens (two pre-soiled and two white per test

load) were tested on the face and back sides on the Color

Eye In order to obtain an initial reflectance reading. The

specimens were placed in the pressure-loaded specimen hold­

er one at a time and a reflectance reading was taken. The

initial set of readings was the basis for determining whether

the fabric became consistently whiter or grayer.

After the initial reflectance readings were taken, the

specimens were ready to be laundered. Two hundred and fifty

milliliters of distilled water were poured into each of the

steel cylinders. Ten steel ball bearings were added to each

cylinder to provide the agitation necessary and to simulate

the agitation of an automatic washer. The specified amount

of detergent was added as previously determined for the

33

individual tests. Bleach was added also at this time to

the wash liquor.

Lastly, the soiled specimens, clean specimens, and

dummy pieces were added to the solution in each of the steel

cylinders. The cylinders were clamped into the Launder-

Ometer which was previously half filled with water heated

to appropriate temperatures, 150**P, 120®P, and 90®P. The

cylinders were rotated for twenty minutes in the Launder-

Ometer. A nine minute wash in the Launder-Ometer corres­

ponds to a fifteen minute home laundry process.

The cylinders were removed, the wash liquor discarded,

the specimens removed, rinsed with tap water and then put

through a manual wringer to remove all the excess moisture.

Then, they were placed back in the steel cylinders with the

ball bearings and 250 milliliters of distilled water for the

rinse. The rinse water temperature in the Launder-Ometer

was thirty degrees lower than the wash temperature. The

cylinders were again clamped in the Launder-Ometer and al­

lowed to rotate for ten minutes to simulate the rinse cycle

of an automatic washer. After the specimens had been washed

and rinsed, they were removed, wrung out, placed on a piece

of white cardboard, and then placed in a drying oven for ap­

proximately twenty minutes. After the specimens were dry,

they were placed in a control room for at least twelve hours

before another set of reflectance readings was taken. This

process was continued until all specimens were washed for

twenty-eight times, accounting for 56O minutes of washings.

34

Reflectance readings were taken after each of the following

washes: 1, 3, 6, 10, 15, 21, and 28. The test data were

not reported beyond twenty-eight washes as continued washings

no longer indicated significantly altered reflectance between

treatments.

Phase II

Modifications and changes were made based on the find­

ings on the Phase I study. The fabric specimens for this

step were 100$ cotton and 100$ Dacron polyester. The use

of bleach was also deleted because it did not account for

any noticeable amount of cleanliness in the test fabrics.

The high temperature was changed to 160**F and the other two

temperatures were kept at 120°P and 90®P, correspondingly,

the rinse temperatures were 130®P, 90®P, and 60*'P. The type

of detergents used was also changed from Oxydol to Tide,

because it seemed to be more representative of the anionic

detergent, and Kenmore was used to represent the non-ionic

detergent. All three concentrations of detergents were

tested in Phase II of the study.

Reflectance readings were taken only twice—the original

reading before the tests began on both the soiled and white

specimens and another reading after the tests were com­

pleted. It was decided that the specimens would be laundered

for 400 minutes or eight washes of fifty minutes and with

twenty minute rinses to speed up the laundering process by

reducing the number of washes and rinses. A factorial

35

design was used which incorporated each combination of

detergent, wash temperature, and detergent concentration.

The experiment was conducted like Phase I of the study

in methods with the exceptions previously mentioned.

CHAPTER IV

FINDINGS AND INTERPRETATIONS

Phase I

The results of Phase I of the study were analyzed and

changes were made before conducting Phase II of the study.

A 50/50 cotton/polyester blend fabric was used in Phase I

of the study. The soiled fabrics were washed to determine

which combination of detergent, water temperature, and

detergent concentration was the most effective. White fabrics

were also washed with the soiled fabrics to determine if they

became whiter, remained the same, or became more soiled due

to redeposition.

In Phase I of the study, initial reflectance readings

were taken on the untreated fabrics; this was the basis for

determining the effectiveness of each treatment. After the

original reading was taken, the specimens were laundered

and reflectance readings were taken at various intervals.

Table 2 indicates the results of the reflectance readings

of the different treatments after twenty-eight washes.

The results indicate that the high detergent concentrations

were the most effective in cleaning the pre-soiled fabrics

at all three wash temperatures. After the first wash, the

non-ionic detergent indicated the greatest change in cleans­

ing the soiled fabrics. 36

37

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38

The high wash temperatures were the most effective at both

detergent concentrations. The least efficient was the anionic

detergent at 120**F and 90®F at both concentrations.

Table 3 indicates the results of reflectance readings

on the white fabrics. The greatest change was after the

first wash. The anionic detergent at 150®F and high concen­

tration cleansed the white fabrics the best. The non-ionic

detergent was the least effective after the first wash, but

after twenty-eight washes the reflectance readings of the

white fabrics varied very little. All of the reflectance

readings were higher after twenty-eight washes than before

the laundering process.

The mean reflectance readings of the soiled 50/50 cotton/

polyester blend are shown in Table 4. The non-ionic deter­

gent cleansed the pre-soiled fabrics most efficiently, but the

mean reflectance results of the white fabrics were very

similar for both detergents after the first wash.

The specimens in Phase I of the study were laundered

twenty-eight times. The washing process could have been

stopped earlier, but the soil removal would not have been as

great. The washing process could also have been carried out

for a longer period of time, and the fabrics would have

eventually become cleansed to their original point of being

white. An analysis of variance was run (Table 5) which in­

cluded both detergents on both the pre-soiled and white fab­

rics. The analyses indicated the differences between the

treatments and within the treatments. The largest ratio

39

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V O b - C O O - s l - O - s r t — O O V O O C M

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40

TABLE 4

MEAN REFLECTANCE OP SOILED 50/50

COTTON/POLYESTER BLEND

No. of Wash??

Anionic Detergent Mean

Non-ionic Detergent Mean

Pre-soiled Fabrics

0 1

3 6

10

15 21 28

White Fabrics

0 1

3 6

10

15 21 28

26.73 30.30 32.42 33.01

34.87 35.61 36,48

37.13

86,63 88.26

89.53

89.23 89.25

89.30 88,88 88.68

26.66

29.75 33.68

35.69 37.09 38.58 40.61 42.50

86.77 85.31 88.80

89.03 89.18

89.22 88.98

88.91

TABLE 5

PHASE I ANALYSIS OF VARIANCEi BOTH

TYPES OF DETERGENT INCLUDED

^1

No. of Washes

V a r i a n c e Between

T r e a t m e n t s

P r e - s o i l e d F a b r i c s

0

1

3 6

10

15 21

28

White F a b r i c s

0

1

3 6

10

15 21

28

0 .1013

7.634-0

8 .8806

16.074-3 28.7218

4-5.7885

70 .0689

88.1157

0 .1220

7 . 9 7 5 1 1.1570

0 .7609

0 .3999

0.4-319

0 . 6 8 7 1

0 .7^^7

VariEuice Wi th in

T r e a t m e n t s

0 .1965 0 .5336

O.3I83 0 .2588

0 .1597 0 . 1 8 8 1

0.164-9

0.24-19

0 .2192

0.164-5 0 .1182

0 , 0 6 5 ^ 0 .0590

0 .0709 0 .0962

0 .0655

F R a t i o

0 .5155

14.3065 27.9000

62.1108

179.84-80

24-3.4-260

4-25.4-330

364-. 264-9

0.5479 4-8.4808

9.7884-

11.6345

6.7779 6.0916 7 .1424

11.3694

42

was indicated after twenty-one washes, then the ratio start­

ed to decrease. The first twenty-one washes were the most

significant in soil removal; after this number of washes,

the test was less sensitive in distinguishing between treat­

ments and in the specimens becoming more uniformly clean.

The minimum significant differences in the reflectance,

both main effects and interactions, are indicated in Table 7

for the pre-soiled fabrics and Table 8 for the white fabrics.

The significance of differences was calculated for each of

the combinations by using the jC-test, The :e-test determined

the minimum significant differences at the 5$ level.

^-. difference of Means M.S.D, «^ /2 S^ standard error of differences ^ n

J6 is the value for 95$ confidence at'x)p degrees of freedom ^

2 S is the residual variance

n is the number of readings on which each mean is based

i? 2 Is *^® number of residual degrees of freedom

The F test was also calculated for Phase I and Phase

II of the study to determine the significant P values at

the 5$, 1$, and 0.1$ levels (Table 6).

Of the main effects in Table 7, that of detergent was

significant, the non-ionic cleaning the pre-soiled fabrics

the most effectively. Between the two concentrations, the

2 grams per liter was more effective in cleaning the samples.

All three temperatures were significant, but 150®F seemed

TABLE 6

CRITICAL P VALUES

43

36

54

Level

5$

1$

0.1$

5$

1$

0.1$

1

4,11

7.39

10.20

4,02

7.14

12.10

2

3.26

5.25

8.42

3.17

5.03

7.88

4

2.64

4.38

6.75

2.78

4.36

6.27

to cleanse the fabrics the best, the greatest change being

when the temperature was between 120®F - 150®P.

The detergent-temperature interaction indicated

significant differences in reflectance, and indicated syner­

gism between these two variables, the non-ionic detergent

being the more effective at all three wash temperatures, but

the greatest differences were at the wash temperature of 150®P,

The differences with the detergent-concentration interaction

were significant, the highest concentration being the most

effective, primarily at the high wash temperature. When the

wash temperature was raised, the amount of concentration was

more effective in cleaning the specimens. As the wash temp­

erature was lowered, the differences in reflectance readings

were not as significant.

The main significant differences in the white speci­

mens (Table 8), also indicated that the non-ionic detergent

44

TABLE 7

SIGNIFICANT DIFFERENCES IN REFLECTANCE

OF PRE-SOILED FABRICS

(ORIGINAL READING 26.70)

Main Effects

Detergents M.S.D. « .29

Anionic 37.13

Non-ionic 42,50

Concentrations M.S.D. = .29

2 g/1 39.85

2/3 g/1 38.82

Temperatures M.S.D, = .35

150*» 44.3^

120® 37.83

90«» 37.28

Detergent-Temperature Interaction M.S.D. = .67

Temperature (**F)

150

120

90

Detergent Anionic Non-ionic

40.19

35.75

35.^6

48.48

39.92

39.10

TABLE 7—Continued

^5

Detergent-Concentration Interaction M,S,D, =* ,55

Concentration

2

2/3

Detergent Anionic Non-ionic

37.79

36.47

43.83

41.17

Temperature-Concentration Interaction M.S.D. = ,67

Temperature (*>F)

150

120

90

Concentration 2 2/3

46.30

38.13

38,00

42.38

37.5^

36.56

46

TABLE 8

SIGNIFICANT DIFFERENCES IN REFLECTANCE

OP WHITE FABRICS

(ORIGINAL READING 86.70)

Main Effects

Detergents M.S.D, » .15

Anionic 88,65

Non-ionic 89.06

Concentrations M.S.D. * .15

2 g/1 88,90

2/3 g/1 88.91

Temperatures M.S.D, = .18

150<» 88,34

120«» 88,91

90«* 89.32

T

Detergent-Temperature Interaction M,S,D, « .35

Temperature («F)

150

120

90

Detergent Anionic Non-ionic

87.88

88,86

89.20

88,79

88,96

89.44

TABLE 8—Continued

Concentration (g/1)

2

2/3

Detergent Anionic Non-ionic

88,82

88.47

88.90

89.90

Temperature-Concentration Interaction M.S.D. » .35

47

Detergent-Concentration Interaction M.S.D. « ,28

Temperature (*»P)

150

120

90

Concentration 2 2/3

88,45

89.18

89.08

88.22

86.64

89.56

48

was the most effective, but the results in reflectance for

both detergents were significant. The differences in the

effects of all three temperatures were significant, but the

fabrics remained the whitest at the lowest temperature.

The high temperature accounted for the most redeposition on

the samples; this may be due to the lower soil removal at

90°P on the soiled specimens, so less soil redeposlted it­

self on the white fabrics, Redeposition did not appear to

be affected by concentration.

Phase II

The results from Phase I were used to formulate the

design for Phase II of the study. The use of bleach was

deleted because it did not account for a noticeable change

in the amount of soil being removed from the specimens.

The high wash temperature was raised from 150°F to l60*P to

determine whether a higher temperature was more effective in

the removal of soil. Three detergent concentrations were

used in Phase II, the recommended amount being included to

determine its effectiveness. Prom the results of the anal­

ysis of variance in Phase I, the specimens were subjected to

the various treatments for the equivalent of twenty machine

washes, because this was the most sensitive in distinguishing

between the treatments. The samples were laundered for fifty

minutes and then rinsed for twenty minutes. This longer time

in laundering and rinsing process accounted for the higher

amount of soil redeposition on the white fabrics in Phase II

49

of the study. The fabric samples laundered in the second

phase were 100$ cotton and 100$ Dacron polyester.

Table 9 shows the results of the analysis of variance

of the pre-soiled cotton. The sources of variation were

all highly significant with the exception of the detergent-

concentration interaction. The levels of significance were

calculated by comparing the variance ratios with the signi­

ficant P values, and Table 10 indicates the differences in

reflectance, both main effects and interactions, of the

soiled cotton. Both detergents were significant; however,

the non-ionic detergent produced a significantly higher re­

flectance in cleaning the soiled cotton. All three concen­

trations were significant, the greatest difference in re­

flectance was in the high concentration. There were signif­

icant differences in the effects of the wash temperatures.

The highest temperature was the most efficient at cleaning

the soiled specimens. The 90®P wash temperature was more

efficient than the 120®P temperature. The best combination

for cleaning the soiled specimens was the non-ionic deter­

gent at 2 grams per liter washed at l60°P.

The analysis of variance on the white cotton (Table 11)

indicated the results of the reflectance reading for all of

the treatments to be highly significant. The non-ionic deter­

gent was the most effective (Table 12). The three concen­

trations were significantly different, the highest concen­

tration had the highest reflectance. The lowest concentration

was the least effective, the reflectance readings were lower

50

TABLE 9

ANALYSIS OF VARIANCEt REFLECTANCE

OP SOILED COTTON

Source of Degrees of Sums of Mean YarAfttAon Frggdom SaUaCjeS Sauarea Ratio Sicrnif icance

Detergent 1 136.317 136.317 134.594 *»«

Concentration 2 257.510 128.755 127.127 *«*

Temperature 2 161.979 80.990 79.966 *««

Detergent-Concentration 2 2.085 1.043 1.029 NS

Detergent-Temperature 2 37.017 18.509 18,275 *»*

Concentration-Temperature 4 21.165 5.291 5.224 «ft

Detergent-Temperature-Concentratlon 4 21.549 5.387 5.318 «*

Within Replicates 5^ 54.690 1.0128

TABLE 10

SIGNIFICANT DIFFERENCES IN REFLECTANCE

OP PRE-SOILED COTTON FABRIC

(ORIGINAL READING 24.32)

51

Main Effects

Detergents M.S.D. « .48

Anionic 32.52

Non-ionic 35.41

Concentrations M,S,D, • .58

2 g/1 36.62

1 1/3 g/1 33.91

2/3 g/1 31.56

Temperatures M.S.D. » .58

160*> 36.03

120<* 32.30

90<> 33.56

Detergent-Temperature Interaction M.S.D. « 1.11

Temperature Detergent Anionic Non-ionic,

160

120

90

33.77

31.85

31.94

38.28

32.76

35.18

TABLE 10—Continued

Detergent-Concentration Interaction M.S.D, - 1.11

52

Concentration (g/1^

Detergent An3,pnX<? Non-ionlG

2

1 1/3

2/3

34.80

32,37

30.39

38,03

35.46

32,73

Temperature-Concentration Interaction M.S.D, » 1,35

Temperature (°P)

160

120

90

Concentration 2 1 1/3 , 2/3

38.42

35.61

35.22

36.31

31.92

33.52

33.36

29.38

31.95

-I m

53

TABLE 11

ANALYSIS OF VARIANCEi REFLECTANCE

OF WHITE COTTON

Source of Degrees of Sums of Mean Variation Freedom Squares Squares Ratio Significance

Detergent 1 l8,36l 18.361 353.776 »»»

Concentration 2 34.193 17.097 329.421 »»»

Temperature 2 44.863 22.432 432.215 »**

Detergent-Concentration 2 7.736 3.868 74.527 ***

Detergent-Temperature 2 15.605 7.803 150.036 ***

OJi ,,'1

Concentration- n Temperature 4 2.744 0.686 13.217 ***

Detergent-Temperature-Concentration 4 1.500 0.375 7.225 ***

Within Replicates 54 2.805 0.0519

54

TABLE 12

SIGNIFICANT DIFFERENCES IN REFLECTANCE

OP WHITE COTTON

(ORIGINAL READING 87.60)

Main Effects

Detergents M.S.D. = .11

Anionic 86.59

Non-ionic 87.72

Concentrations M.S.D, = ,13

2 g/1 87.96

1 1/3 g/1 87.39

2/3 g/1 86.11

Temperatures M.S.D. « .13

160<> 86.42

120*> 86.64

90*> 88.41

Detergent-Temperature Interaction M.S.D. « .25

TABLE 12—Continued

Detergent-Concentration Interaction M.S.D, « .25

55

Concentration (K/1)

2

1 1/3

2/3

Detergent Anionic Non-ionic

87.77

86.95

85.04

88.15

87.32

87.19

Temperature-Concentration Interaction M.S.D. « .31

Temperature (*»P)

160

120

90

—

Concentration 2 1 1/3 2/3

86.99

86.49

89.27

86,80

86,49

88,88

85.48

85.80

87.08

56

than the original reading after twenty washes. At 90**P

the white fabric had a higher reflectance than originally;

at 160®P there was redeposition because more soil was re­

moved from the pre-soiled samples at the wash temperatures

of 120**P and 90®P.

Table 13 indicates the analysis of variance; the re­

flectance of the pre-soiled polyester was significant at

the 1$ level for all of the sources of variance. The sig-

nicant differences, both main effects and interactions, of

the pre-soiled polyester (Table 14) indicated that the non-

ionic detergent did a much better cleaning Job than did the

anionic detergent. Of the three concentrations, the highest

was most effective for cleaning the polyester. There was

little difference in the reflectance readings between the

high and medium concentrations. The low concentration was

by far the least effective. Of the three temperatures, the

high temperature cleansed the soiled samples the best. There

were little differences between the 120°P and 90®P wash tem­

perature in reflectance. The most effective cleansing com­

bination for the soiled polyester was the non-ionic deter­

gent at 2 grams per liter laundered at l60°P.

There was synergism between the temperature and con­

centration combination. The most effective cleansing effects

on both the cotton and polyester specimens occurred at the

highest detergent concentration and wash temperature. When

the wash temperature was lowered, with the concentrations

remaining high, the cleaning effectiveness was not as great

57

TABLE 13

ANALYSIS OP VARIANCEI REFLECTANCE

OF SOILED POLYESTER

Source of Degrees of Sums of Mean YarlatlQn FreedQw Squares Squares Ratio significance

Detergent 1 387.115 387.115 222.915 ***

Concentration 2 212,281 106.141 61.120 »»»

Temperature 2 99*326 46,663 28.597 ***

Detergent-Concentration 2 24.507 12.254 7.056 *»«

Detergent-Temperature 2 37.297 18.649 10.738 »»»

Concentration-Temperature 4 42.036 10.509 6.051 *•*

Detergent-Temperature-Concentration 4 36.242 9.061 5.217 **

Within Replicates 54 93.780 1.7366

TABLE 14

SIGNIFICANT DIFFERENCES IN REFLECTANCE

OP PRE-SOILED POLYESTER FABRICS

(ORIGINAL READING 25.89)

58

Main Effects

Detergents M.S.D, = ,62

Anionic 35.68

Non-ionic 40,51

Concentrations M,S.D. « .76

2 g/1 39.82

1 1/3 g/1 38.83

2/3 g/1 35.63

Temperatures M.S.D. = .76

160O 39.72

150<* 37.77

90« 36.79

, ' i i •"< iiiiiii

Detergent-Temperature Interaction M.S.D. « 1.45

Temperature (°F)

160

120

90

Detergent A n i o n i c lsjpn-1 nni a

36,35

35.44

35.24

43.09

40,10

38,34

TABLE 14—Continued

59

Detergent-Concentration Interaction M.S,D. • 1,45

Concentration (K/l)

2

1 1/3

2/3

L

Detergent Anionic Non-ionic

38.03

35.62

33.38

41.61

42.03

37.89

Temperature-Concentration Interaction M.S.D. « 1.77

Temperature (°F)

160

120

90

Concentration -> 1 1/

42.15

39.81

37.51

41,15

37.98

37.37

ZH

35.88

35.53

35.18

60

as with the high temperature. At the low temperature, the

effect of concentration on reflectance was very slight in

the amount of cleanliness in relation to the higher temper­

atures. The use of additional detergent was ineffective

and wasteful at low temperatures, but became worthwhile in

hot water. Likewise, because of this synergism, there was

no point in raising the water temperature unless at least

the recommended amount of detergent was used.

Table 15 indicated the results of the analysis of

variance for the white Dacron polyester. All of the sources

of vjiriation were highly significant at the 1$ level. Table

16 indicated that of the two detergents, the non-ionic kept

the white fabrics the cleaner or allowed less redeposition.

Of the reflectance readings on the white polyester,

both had lower reflectance readings after twenty washes

than before any treatments were applied. The effects of

concentration were the least effective in keeping the white

specimens white. The 90°P temperature kept the specimens

the whitest, but that was due to redeposition at the high

wash temperature because more soil was removed from the pre-

soiled samples at the higher temperature.

Between the two fabric types, the 100$ polyester became

cleaner after twenty washes than did the cotton when the

non-ionic detergent was used at the highest concentration

and the highest wash temperature. Of the white specimens,

the greatest amount of redeposition occurred at l60°F with

the high concentration of non-ionic detergent.

61

TABLE 15

ANALYSIS OF VARIANCE* REFLECTANCE

OP WHITE POLYESTER

Source of Degrees of Sums of Mean

Detergent

Concentration

Temperature

Detergent-Concentration

Detergent-Temperature

Concentration-Temperature

Detergent-Temperature-Concentration

Within Replicates

1

2

2

2

2

4

4

54

36.865

53.498

7.644

13.265

6.037

2.262

9.191

3.215

36.865

26.749

3.822

6,633

3.091

0.566 1

2.298

0.0595

619.579

449.568

64.235

111,478

50.739

9.512

38.621

«««

ft»ft

»««

««»

«««

«««

f ftft

62

TABLE 16

SIGNIFICANT DIFFERENCES IN REFLECTANCE

OP WHITE POLYESTER

(ORIGINAL READING 88.52)

Main Effects

Detergents M.S.D, = ,12

Anionic 85.71

Non-ionic 87.73

Concentrations M.S.D. « ,l4

2 g/1 87,49

1 1/3 g/1 86,87

2/3 g/1 85.21

Temperatures M.S.D. = .14

160** 86.23

120*» 86.30

90® 87.04

Detergent-Temperature Interaction M.S.D. « .27

Temperature ( F)

160

120

90

Detergent Anionic Non-ionic

85.82

85.09

86.23

86.63

87.51

87.86

TABLE 16—Continued

Detergent-Concentration Interaction M.S,D. « .27

Concentration (g/1)

1 1/3

2/3

Detergent Anionic Non-ionic

87.23

86.12

83.79

87.75

87.62

86,63

Temperature-Concentration Interaction M,S.D, = .31

63

Temperature (°P)

160

120

90

Concentratior 2 1 m

87.09

87.48

87.91

•

86.36

86.75

87.51

I

2/3

85.24

84.68

85.71

64

Cost-Benefit Analysis

A cost-benefit analysis was done for Phase II of the

study to determine which combination of detergent, temper­

ature, and concentration was the most efficient and econom­

ical for the consumer. The average cost per wash load was

calculated for each of the above variables.

The major cost per wash load is the operating cost of

the machine. This includes the cost of the machine over a

period of twelve years, interest paid on the machine while

being financed, depreciation, floor space, water used in the

wash and rinse cycles, and the electricity to run the ma­

chine. The fixed costs are estimated as follows:

Water, 40 gallons at ,05«iJ per gallon 2^ Electricity, 2/3 KWH at 3* 2* Depreciation and Interest 7^ Maintenance 2^ Floor Space 2i Total 15T

The average cost of detergent was also calculated. The

cost of the anionic detergent is approximately 36<t per pound.

The percentage of detergent needed per wash was based on the

weight of the fabric, A ten pound load was used as the basis

for the amount of clothes to be laundered in the home launder­

ing process. If ten pounds of clothes were laundered, the

percentage of detergent needed on the weight of the fabric

for the high concentration was 2.5$ or 4 oz. The cost of the

anionic detergent, costing 36i per pound, and the approximate

cost per wash load for the non-ionic detergent which is 40•

per pound is shown in Table 17.

65

TABLE 17

COST PER WASH LOAD OF ANIONIC

AND NON-IONIC DETERGENTS

Concentration

grams per liter

Anionic

2

1 1/3

2/3

Non-ionic

2

1 1/3

2/3

per unit we

2.50$

1.67$

0.83$

2.50$

1.67$

0,83$

iight oz. per load

4

2 2/3

1 1/3

4

2 2/3

1 1/3

cost per load f(fc

9.0

6.0

3.0

10.0

6.6

3.3

The cost of heating the wash and rinse water was com­

puted for gas as the source of fuel for an 18 gallon wash

at 160®P, 120°P, and 90°P and rinse temperatures thirty

degrees lower. One cubic foot equals 1000 BTUs. One thou­

sand cubic feet cost $1.40 and produce one million BTUs.

At seventy percent efficiency, the cost of adding each thou-

140 sand BTUs to the water equals ,20( per 1000 BTUs. .7x1000

Heat equals the weight of water X the temperature increase

in wash and rinse cycles. Since 18 U,S, gallons of v/ater

weigh 150 pounds, the heat required » 150 (T-60) BTUs.

The cost of heating the water is as follows:

90**F - 150 X 30 + 0 » 4500 BTU/wash 0.9* 120**F = 150 (60 + 30) « 13500 BTU/wash 2.7* 160°P - 150 (100 + 70) - 25500 BTU/wash 5.1*

TABLE 17

COST PER WASH LOAD OP

ANIONIC AND NON-IONIC DETERGENTS

65

Concentration

grams per 3-lt r

Anionic

2

1 1/3

2/3

Non-ionic

2

1 1/3

2/3

per unit we of load

2.50$

1.67$

0.83$

2.50$

1.67$

0.83$

ight oz. per load

4

2 2/3

1 1/3

4

2 2/3

1 1/3

cost per load (<t)

9.0

6.0

3.0

10.0

6.6 3.3

The cost of heating the wash and rinse water was com-

pited for gas as the source of fuel for an 18 gallon wash

at 160®P, 120°F, and 90°F and rinse temperatures thirty

degrees lower. One cubic foot equals 1000 BTUs. One thou­

sand cubic feet costs $1.40 and produces one million BTUs.

At seventy percent efficiency, the cost of adding each thou­

sand BTUs to the water equals ^^^[^[QQQ = .20* per 1000 BTUs.

Heat equals the weight of water X the temperature increase

in wash and rinse cycles. Since 18 U.S. gallons of water

weigh 150 pounds, the heat required = 150 (T-60) BTUs.

The cost of heating the water is as follows:

90*'F » 150 X 30 + 0 « 4500 BTU/wash 0.9* 120®F = 150 (60 + 30) « 13500 BTU/wash 2.7* 160°F = 150 (100 + 70) « 25500 BTU/wash 5.1*

66

These figures were calculated for each of the wash

temperatures, concentrations, and detergent combinations.

The cost per wash load for the home laundry varied from 30.1*

for the non-ionic detergent at a wash temperature of l60®P

at the high concentration to 18,9* for the anionic detergent,

low concentration and a wash temperature of 90®P.

The benefit was also calculated for each of the concen­

trations and wash temperatures for the pre-soiled fabrics by

subtracting the original reflectance reading from the re­

flectance reading after twenty washes. The benefit varied

from 20.02$ on the polyester using the non-ionic detergent

at the recommended level at 160®F to 4.53$ on the cotton

using the anionic detergent, lowest concentration, 90°F,

Figures 1 and 2 show the results of the cost-benefit

ratio. The best results were calculated by drawing tangent

lines from the origin to the point where the efficiency was

the highest. The three points for each temperature repre­

sents the three different concentrations of detergent. The

highest cost-benefit ratio for the cotton (Figure 1) was

with the non-ionic detergent at the recommended amount of

detergent at l60**F, costing 26.7* per wash load. The next

best ratio was the high concentration of non-ionic detergent

at 90**P costing 26* per load and 160®P costing 30.1* per

load. The least efficient ratio was the low concentrations

of the anionic detergent at all three wash temperatures.

The results of the pre-soiled polyester (Figure 2) were

similar to those of the cotton in that the non-ionic

67

ti o

o o

o 03 •H CO >>

cd ti <

•H -< 0) c <u

CQ I

+i OQ

o o I i

•H

68

69

detergent was the most efficient at the high and medium

concentration levels. The anionic detergent was the less

efficient, but if the anionic detergent is to be used by

the consumer, the best results are at the highest concen­

trations.

The best cost-benefit ratio for the polyester was at

the recommended amount of the non-ionic detergent with the

high wash temperature, costing 26.7* per load. The next

highest ratios were still with the non-ionic detergent, but

at the recommended level at 120°F costing 24.3* and the high

concentration at l60°F costing 30.1* per wash load. The

least efficient ratio was with the anionic detergent at the

low concentrations at all three wash temperatures.

CHAPTER V

CONCLUSIONS

The major purposes of the study were to determine how

to cleanse cotton and synthetic fabrics and to determine the

most efficient cost-benefit ratio. The most effective com­

bination of variables used for cleaning the cotton and syn­

thetic fabrics was the non-ionic detergent (Kenmore) when

used at the highest concentration with 160°P wash temperature,

Of the two types of fabrics, the synthetics became cleaner

after repeated launderings. The most efficient cost-benefit

ratio for both types of fabrics was the non-ionic detergent,

costing approximately 26* per wash load at the recommended

amount of detergent with 160**F wash temperature.

If further research is to be conducted concerning the

laundering of textiles, the study could be improved by using

the washing machine instead of the Launder-Ometer, and by

laundering garments that have been soiled by wear. By using

the washing machine, the washing cycle would be similar

to the home laundry process, and the results could better

assess the amount of soil redeposition and the amount of

wrinkling caused by laundering. Soil redeposition and

wrinkling are major problem areas for synthetic fibers, and

more information is needed for the consumer to satisfactorily

launder her garments. 70

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1. Burnthall, E. V. and Lomartlre, J. "Polyester Fibers: Problems and Solutions". Journal of American Asso­ciation of Textile Chemists and Colorlsts. Volume 2', Wo. l3, July l970.

2. Changing Times. The Kiplinger Service for Families. "Soaps, Detergents and why Nobody Can Say What's Best". June, 1972.

3. Davis, Richard C. "Washing Machines and Dryers Are Tex­tile Processing Machines". Journal of American Asso­ciation of Textile Chemists and Colorlsts. November,

4. Detergents and Detergency. Uniliver Educational Booklet. (Excerpts) "Detergents", 1970.

5. Fort, Tomilinson, Billlca, H. R. and Grindstaff, T. H. "Studies of Soiling and Detergency". American Oil Chemists' Society. May 1968.

6. Gibbons, Ruth. "Facts About Laundering". Textiles. Volume 1, No. 3, October 1972.

7. Hensley, James W. "Soil Redeposition Versus Deposition Tests in Evaluation of Laundry Detergents". American Oil Chemists' Society Journal. November 1965.

8. Holker, J. R. "Soiling and Fabrics". The Shirley Link. The Cotton, Silk and Man-Made Fibre Research Associa-tion. Summer, 1968.

9. Hunter, Robert T. "Factors Affecting the Performance and Appearance of Laundered Synthetic Fabrics". American Oil Chemists' Society Journal. Volume 45, May 19btJ. ~""

10. Jackson, Agnes and Rogers, B. The Principles of Domestic and Institutional Laundry Works.Edward Arnold and Company. London. 193^.

11. Jones, D, M, "Cotton", The Shirley Link. The Cotton, Silk and Man-Made Fibre Research Association. Summer 1968.

71

7P 12. Levitt, Benjamin. "Surfactants and Surface Activity".

()ils. Detergents, and Maintenance Specialltlea: Volume 1 Materials and Processi?: Chemical Publish-ing Company. New York. 1967^—

13. Loeb, L. and Pollard, S. J. "The Effects of Bleaching in Home Laundry". Journal of American Association of Textile Chemists and Colorlsts. Volume 2. No. 22. November 1970, *

14. Panko, J. G. "Problems in Laundering and Dry Cleaning". The Shirley Link. The Cotton, Silk, and Man-Made Fibre Research Association. Summer I968.

15. Perdue, G. R. The Technology of Washing. The British Launderers' Kesearch Association, London. 1966.

^^* Sanitation in Home Laundry. Consumer Service of the United States Department of Agriculture. October 1971.

17. Sears U. B. C. Control Book on Detergents, Research and the Kenmore Non-Phosphate Detergent. 1970.

18. Soaps and Detergents for Home Laundry. Home and Gardens Bulletin United States Department of Agriculture, Washington D, C. I967.

19. The Care and Tending of Knitted Fabrics the Kenmore Laundry V/ay. Sears and Roebuck and Company. 1972.

20. Technical Manual of the American ABsociatlon of Textile Chemists and Colorlsts. "Standard Machine for Lab­oratory V/ashing Tests—The Launder-Ometer, I966.

21. Wingate, Isabel, Textile Fabrics and Their Selection. Prentice-Hall, Inc. Englewood Cliffs, New Jersey. 1970.

22. Witt, Cherl and Warden, Jessie, "Can Home Laundry Stop the Spread of Bacteria in Clothes?" Journal of the American Association of Textile Chemists and Colorlsts. Volume 3, No. 2. July 1971.

23. The Laundry Book. Calgon Corporation Consumer Division. Pittsburgh, Pennsylvania. 1972,