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 DOI: 10.1177/004051757204200705

1972 42: 404Textile Research JournalReidun Löwendahl and Harald Åsnes

Wash-and-Wear FabricsLaundering Conditions for Improved Wash-and-Wear Appearance: Part II: Machine Washing of

  

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Laundering Conditions for Improved Wash-and-Wear AppearancePart II: Machine Washing of Wash-and-Wear Fabrics

REIDUN LÖWENDAHL AND HARALD ÅSNES

Swedish Institute for Textile Research (TEFO), Gothenburg, Sweden

ABSTRACT

The variables that effect the appearance of wash-and-wear fabrics in home laundering have been studied in an effort todevelop recommendations for more effective, safer washing methods for better appearance. The study was confined to thedefect of soaking, amount of load, mechanical action, and washing temperature in home laundry machines on the appear-ance of wash-and-wear fabrics. The present investigation showed that the amount of load and the type of washing pro-gram were of great importance for the appearance. A low loading in the washing machine and a "continuous" drumrotation, including very short stop periods, are effective in minimizing wrinkles. Short spin-drying periods will not re-duce the appearance rating substantially.

KEYWORDS

Wash-and-wear fabrics; durable-press fabrics; easy-care fabrics. Laundering; washing; washing machine; washing

temperature; washing program; mechanical action; spin drying. Appearance; smooth drying; creases; wrinkles.

,

Introduction

The importance for the wash-and-wear appearanceof changing swelling, temperature, and time conditionsfor crease formation and recovery in wash-and-wear

fabrics, has been pointed out in Part I of this work.In the laundering processes, wrinkling and recovery willoften take place during simultaneous changes of theabove mentioned physical conditions.The conditions of swelling are not only determined

by the dry-wet-dry cycle during laundering, but alsoby the pH and composition of the detergent. Duringwashing, the textile material is subjected to swelling ina wrinkled position. According to Liljemark el al. E6],cotton fabrics will wrinkle more during an increase inhumidity than at equilibrium conditions. As shown

by the same authors, this increase in wrinkling is pro-portional to the steepness of the moisture absorptionisotherm. Under wet conditions, this wrinkling is

probably connected to the swelling isotherm in a similarmanner. An increase in the polyester content in theblend or a resin treatment both lead to ’a lower swellingisotherm and, therefore, less wrinkling would be

expected. ,

’

Farnworth and Lindberg ~2~ have shown that

creased fabrics containing wool and cotton show pro-gressive, step-wise recovery when subjected to repeatedrewetting drying cycles, and Wilkinson and Hoffman[12] found that wear wrinkles recover on washing.The time and amount of crease formation and re-

covery during washing will be governed by the me-chanical action determined by the construction of the

machines as well as the washing load. In an attempt to

analyze the causes of wrinkling in washing, Wilkinsonand Hoffman [12] stated that the mechanical actionduring washing does not cause wrinkling. They alsomentioned that centrifugal spinning is the major causeof wrinkling in automatic washing machines. If the

fabrics are removed from the washing machine beforethe spin cycle and allowed to &dquo;drip dry,&dquo; they are es-scntially free from wrinkles. The important wrinkle-producing action in washing, according to the same

authors, is the compression of the fabrics during drain-ing and spin drying while they are hot. Mechanical

action, while the fabric is hot, tends to overcome theeffect of the interfiber friction and allows the fibers toreturn to their former equilibrium positions.

In their investigations on home laundry equipment,Taube et al. ~9~ have shown that, when slow andregular agitation speeds were used, the trend wastowards slightly better scores of the appearance ratingfor those swatches agitated at normal speed, althoughthe differences were small. Very little attention hasbeen paid to the question of the influence of the me-chanical action on wrinkling except for the investiga-tions mentioned above.The mechanical impact on textiles during laundering

has, however, far reaching consequences for manytextile properties like shrinkage, felting, cleaning, wearoff and pilling. Adequate measurements of the me-chanical action in washing applicable to all these

changes in the textile properties seems to be lacking.However, the effect on the washed textiles of some of thedifferent mechanical parameters of the washing machine

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405

have been investigated, thus Henning et al. [4~ havestudied the effect of the speed of rotation of the drumon the felting shrinkage of wool. They found that, byvarying the speed of rotation, the maximum shrinkageoccurred at a peripheral speed of 65 m/min. They alsoshowed that raising the liquor level produced a dis-tinct reduction in felting. The amount of feltingshrinkage which occurs in rotary drum washing machineis not only influenced by peripheral speed, liquor height,and liquor ratio, but also by the number and form ofthe lifters.

Similar results are reported by (iruoner [3~ whoshowed that the shrinkage of wool was smallest in thewashing machine with the highest speed, and largestwhen the g-factor was between 0.7-0.9. Largeramounts of water gave less shrinkage.Schmidt [7~ has studied the effect of the drum speed

on cleaning and wear off. He noticed that the testedmachines of 450, 750, and 1100 mm in diameter hadthe optimal speed of 78, 102, and 132 m/min, with 56,43, and 38 rotations/min which is close to the speed.when centrifugal conditions occur in the washing drum.Although wear off increased up to the optimum speed ofthe drum, this was counteracted by the possible re-

duction in washing time.The mechanical action in the washing machine will

also be influenced by the textile and liquid content ofthe drum during washing. Vaeck and Maes t10~ havestudied the effect of load and mechanical action indifferent washing machines on the shrinkage of wool.They mentioned that the mechanical intensity in-creased when the bath ratio was increased to 22 1/kgand decreased at higher bath ratios. With a low water

level, the mechanical intensity decreased when in-

creasing the load and then fell off again. The influenceof the nature of the liquor in the drum-type washingmachine on the shrinkage of wool is appreciable (8~.The articles do not remain immersed in the liquorthroughout the washing process. They are repeatedlylifted from the liquor by the vanes on the drum and arethen dropped back as the vanes approached the apex oftheir locus. ’The impact caused by the articles re-entryinto the liquor may be cushioned by foam and, if thelatter is present in substantial quantities, a correspondingreduction in the severity of the agitation will take place.

All the washing parameters mentioned here are in-teresting from the point of view of wrinkling appear-ance, because they will influence the time and amountof wrinkle formation and recovery during washing.The impact of these parameters on textile propertiesother than wrinkling is important from a comparativepoint of view.

Experimental

Washing Machine

A domestic washing machine equipped with somespecial devices was used. Technical specifications anddetails of the washing machine were as follows.

Drum diameter-475 mm ~

’

Drum speed-54 rpm (g-f actor = 0.78)Peripheral speed of drum-81 m/min.Spin speed-580 rpm (g-factor = 89)Drum rhythm-~(a) normal 11-12 sec ON, 3-4 secOFF (b) gentle 3-4 sec ON, 11-12 sec OFF

Amount of water-low water level about 12 liters

high water level and rinsing about25 liters

Rinsing-3 rinsing cycles of 3 min each with c014water

After laundering, the specimens were generally line-dried and then evaluated visually using the AATCCThree Dimensional Durable-Press Replicas, 124-1967T.The specimens were 36 X 36 cm.

Textile Malerials

In the main part of the investigation, a resin-treatedplain weave of 67% polyester and 33% cotton, weight213 g/m2, was used. Studies were also made withother blend ratios of polyester/cotton, types of 100%polyester, cotton and polyamide materials, both wovenand knitted fabrics. All textiles were of easy-carequality. Further descriptions of the textiles used, aregiven later.

Detergent and Waler QualityA Swedish standard detergent, VDN-type A,, was

used. This detergent is based on phosphates, the

perborates content about 10% and the pH is maximumat 11.

The quantity of detergent throughout this work wasonly 20 g per washset, which is less than that used innormal domestic laundering. This depended on thisdetergent’s tendency to foam too much.

It was used water with a hardness of about 2.3 DH

(German hardness degree) = 2.4 AH (American hard-ness degree). ..

Results and Discussion

Soaking and Swelling Before Lf’askingTextile specimens were placed without wrinkling in

cold (18°C) water containing detergent for 17 hr.

Afterwards, the specimens were washed at 60°C with anormal program cycle and spin-dried for 30 sec. The

items were without or with resin treatment and ofdifferent weave constructions. Details of the fabricsused are given in Table I.The influence of soaking the textiles before washing

is shown in Figure 1. The standard deviation is about0.5 units of appearance rating.The results showed that if the items were soaked

without wrinkling during the 17 hr before washing, the

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406

I TABLE I. Details of fabrics.

Fic. l. Appearance rating after being washed with or withoutsoaking: U = not treated with resin; R = treated with low con-tent of resin; R+ = treated with high content of resin.

appearance did not deteriorate, and in fact it improvedfor some fabrics. Tests in which the textiles weresoaked for 15 min did riot appear to have any influence

on the appearance. The soaking time must be longenough to permit equilibrium swelling to take place.

Several interesting observations have been made inconnection with this test. ,

’

> 1. Samples of unre~in-treated ~ cotton and 50/50cotton/polyester fabrics tended to be less wrinkled if

soaked before washing.2. The soaking procedure did not affect the appear-

ance of the resin-treated cotton samples. However, theresin-treated 50/50 cotton/polyester specimens ob-

tained a better appearance if soaked before washing.3. Both the resin-free and resin-treated 33/67 cotton/

polyester fabrics did not show any difference if soakedor not before washing.The same type of phenomena were observed by

Enders [1] when studying the wash-and-wear fabrics.,He showed that textiles in a half-dried condition were

especially sensitive to creasing, and the recovery in thisstate were especially affected by the resin treatment.This would also be expected from the observations ofLiljemark et al. [6]. Therefore, wrinkling will occur

more easily when dry fabrics are put in a rotatingwashing machine. Also compare Part I of this work.As shown, the effect of preswelling without wrinkling

is rather small on easy-care fabrics and, therefore, oflittle practical value. Moreover, Horowitz [5] hasshown that prewashing is better than soaking as re-

gards the cleaning effect.

Analysis of 11’ri’hkling and Recovery During WashingAn investigation was done to find out when the

creases appear during the washing process, and how theheating, rinsing, and spinning affect the appearance.

Textile specimens were put in the washing machineand taken out at different stages of the washing processas shown in Figure 2. The same amount of specimenswere taken out and put in at the different stages in-vestigated, so that the. washing load was kept constantthroughout the washing process.

I

FIG. 2. Stages of putting in and out specimens during the wash-ing process. Washing conditions: load-1.7 kg (1:28); washing1)rogram -normal; spinning time-30 sec; washing temperature-85°C.

’

Figure 3 shows the appearance of the specimens whichare put in the washing machine, and Figure 4 the speci-mens which are taken out from the machine at the dif-ferent stages of the washing cycle.

FIG. 3. Appearance of samples put into the washing machine atthe stages of the washing cycle indicated.

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407

FIG. 4. Appearance of samples taken out from the washing ma-chine at the stages of the washing cycle indicated.

Figures 3 and 4 show that the appearance of thecotton specimens did not change much at the differentstages of the washing cycle.From Figures 3 and 4, the following conclusions may

be drawn for the polyester/cotton items.

1. Regarding washing processes with or without

prcwash, there is no difference in the appearance rating.2. If the textiles were only rinsed in cold water,

some wrinkles appeared.3. Specimens taken out from the machine, af ter

being prewashed at 40°C, were less wrinkled than

specimens which underwent the whole process.4. Specimens taken out when the temperature was

highest showed the highest degree of wrinkling.5. The specimens did not show increased wrinkling

after the first cold rinse with the shock temperaturefall, although a shock temperature fall also occurs whentaking the samples out of the hot washing machine.

6. There was no significant improvement in drip-drying the specimens, instead of a short spin-dryingperiod followed by hang-drying, (specimens taken outat i and j in Fig. 4):

’

These are not in agreement with the results quotedby Wilkinson and Hoffman [12]. On the contraryour results show that substantial wrinkling can occurin the washing process and that with a short cold spindrying no spin wrinkles are observed after drying. The

major part of the wrinkles were produced when thetemperature was high. Compare Part I (Figs. 3a,3b) of this work. Also Taube et al. E9] have observedthat as the temperature of the washing increased, thewrinkling increased.

It, therefore, seems obvious that wrinkling shouldoccur during washing. It is the design of the washingprocess, however, which determines if these wrinkles

may recover.

Drum SpeedThree speeds of rotation, 33, 54, and 100 rotations/

min, were used in order to find the effect of the speed

on the appearance of wash-and-wear fabrics after

laundering. ,

Table I I shows the appearance rating after washingwith the change in drum speed, at wash liquor tem-

TABLE II. Appearance rating after washing with different speedsof rotation.

perature of 60 and 85°C, and with 2°C/min rate ofcooling of the rinse water.The appearance of the ’cotton samples was not in-

fluenced by changing the drum speed, while both theappearance of polyester and polyester/cotton samplesdeteriorated at higher drum speeds. Similar resultswere obtained at other rates of cooling of the rinse

water.

With low and high speeds, the load was unable tofall freely during washing and, therefore, the wrinklesmay not recover or be straightened out mechanically.Comparing these results with those for the shrinkage, ,

of wool found bv Henning [4] and (~ruoner ~3~, thefelting shrinkage seems to be largest when the ap-pearance is best. When the mechanical action is high,the shrinkage of wool becomes larger and the appear-ance of wash-and-wear fabrics better.The optimum for the appearance of wash-and-wear

fabrics in this investigation is similarly correlated tothe optimal speed of rotation for the cleaning effectaccording to Schmidt ~7~..

Load lt’eighls al Low anci High nr ater Levels

A study was done to examine how the load affectsthe appearance. The specimens were washed by thenormal program cycle with low and high water levelsand spin-dried 60 sec. By changing the quantities ofthe load, the load:liquor ratio was varied between1:3 and 1:50.

Figures 5 and 6 show the appearance rating of

polyester/cotton fabric as a function of the weight ofload and the load : liquor ratio. The rated 100%capacity of the machine used was 1 kg to 13 1. cagevolume.These figures show that it is very important not to

put too many articles into the washing machine, i.e.,the load ratio must not be higher than 40-50%, about1 kg to 30 l. cage volume. This is of particular im-portance, if the washing is done at a low water level.If a high water level is used, the load ratio can be

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408

FIG. 5. Appearance rating as a function of the toad ratio: 100%= 1 kg per 13 1 cage volume.

FIG. 6. Appearance rating as a function of thebath ratio.

higher. The goods must have enough space for’con-tinuous movements. This is in agreement with Taubeet al. [9] who observed that there was a fairly con-sistent trend towards more wrinkling with largerloads. ’

The mechanical intensity must be high enough toproduce movements of the load. An optimum valuefor the bath ratio as mentioned by Vaeck and Maes[10] has not been observed.

According to Figure 6, the amount of water must notbe smaller than about 14 1 to 1 kg dry materials whenwashing at 85*C. It can be smaller at 60°C washing.Also, Viertel [11] recommends a high water level, i.e.,about 30 v/kg as the best ratio, to wash polyester/cotton blends without wrinkles.

The presence of foam on the surface of the liquormay have an influence on the appearance of wash-and-wear garments, since the shrinkage values increasedsharply as the foaming was suppressed E8].The weight of detergent used throughout this work

was the same when washing with high or low waterlevels. This gave more foaming at a low water leveland may have had an effect on our results.Washing a small load may be quite uneconomic, but

Schmidt [7] has shown that the wear and the cleaningdecreased when the weight of the load increased.

Swanepoel and van Rooyen [8] observed that the drum-type machine did not consume more power when theload was increased from zero (liquor only) to themaximum (3.4 kg). ,, ’.

Mechanical Action ’

The washing machines in current use vary con-

siderably in the intensity of the mechanical action onthe textile materials.The effect of the drum rhythm on the appearance

after washing at different washing cycles is shown inFigure 7. Abbreviations used for the rotation of thedrum:

N = normal rhythmG = gentle rhythmS = no rotation (still)(S) = no rotation during filling and draining(R) = reduction of the rotation time at the maxi-

mum temperature.

FIG. 7. Appearance rating of polyester/cotton items washedat different washing program cycles. Washing conditions: load-1.7 kg (1:28) ; spinning time-60 sec; load/liquor ratio-1: 7 or1:15.

The first letter indicates the rotation during the&dquo;main wash&dquo; without the heating period, the secondletter the heating period, and the third the rinsingperiod.The periods are outlined in Fig. 2. Letterswithin parentheses see above.The effective time of rotation varied between 12%

for the program. G-S-G (S) to 73% for the programN-N-N calculated on the time of the total washingprocess.The results given in Figure 7 were somewhat better

when the washing was performed at the high waterlevel than at the low water level using the gentlerhythm cycle. However, it was unsatisfactory to washwith a high water level and a program in which thedrum did not rotate during heating. This program is

very often recommended for wash-and-wear fabrics,but with this program, the fabrics were the mostwrinkled.With our washing machine, it was proved advan-

tageous for the wash-and-wear appearance at hightemperature washes to let the drum rotate at least

during the last 10 degrees of the temperature increase.For 11 different washing programs the linear regres-

sion coefficients between the appearance and the effec-

tive time of rotation (in %) at 85°C wash were cal-culated and tabulated in Table III.

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409

TABLE III. Regression coefficients between the appearance ratingand the effective time of rotation by different wash programs.

95% confidence level = 0.60.t = appearance rating.m = effective time of rotation in % of the total washing time.

There is no correlation between the appearance andthe effective time of rotation for the cotton and 50/50samples. The 100% polyester and 67/33 blends showa significant correlation at 95% :s level if linear cor-

relation is assumed.

Polyester fabrics seem to be less wrinkled, the higherthe per cent etiective rotation is and long stop periodsseem to produce wrinkles. ’ This is completely oppositeto the shrinkage of wool which shrinks more when themechanical action increases [10~. This is in agree-ment with the pronounced temperature and time effecton creasing of polyester fabrics reported in Part I ofthis work. An improvement in wash-and-wear ap-

pearance by rotation during 10°C temperature in-crease following a non rotating period of heating wouldalso be expected.

Conclusions

Here are some of the tentative conclusions which maybc drawn from this investigation.The effect on the wash-and-wear appearance of

soaking the unwrinkled textile materials before wash-ing is dependent on the water swelling of the textiles.

During the washing process, the main part of thewrinkling occurs when the temperature is at maxi-

mum. The variations of the time for the washingprocess do not seem to have any important intluence onthe appearance. A short spin-drying docs not produceany observed wrinkles.The speeds of the washing drum show a great effect

on the wash-and-wear appearance of the textiles.

Perhaps, further investigations must be done to findthe optimum speed of rotation for washing wash-and-wear fabrics.

The load ratio in the washing machine is an im-

portant parameter in washing wash-and-wear materials.When the weight of the wash load increases, the ap-pearance rating decreases. When washing is at a highload ratio, the result is improved using high waterlevel.

Also, the washing program is important and longstop intervals often produce wrinkles.The trials show that the best wash-and-wear ap-

pearance is obtained:

if the machine does not contain too many articles;if the drum speed is the optimum, g-factor probably

about 0.8 ;if a washing temperature is chosen with considera-

tion of the material to be washed;if the drum revolves during the entire part of the

washing cycle;if the amount of water is adjusted to the washing

program and quantity of the washing load.

These are some of the parameters which have an in-fluence on the appearance of wash-and-wear fabrics bywashing.

A cknowledgmenls. Thanks are due to Mrs. Li . Fahl-strbm for her skilful performance of the experimentalwork. :

Literature Cited

1. Enders, H. Neue Entwicklungen auf dem Gebiet der Hoch-veredlung, insbesondere über "wash and wear," AusrüstungI and II, Melliand Textilber. 40, 1315-1326, 1454-1462

(1959).2. Farnworth, A. J. and Lindberg, J. The Influence of Changes

in Moisture Content on the Wrinkle Recovery of Fabrics,Part I, Textile Res. J. 31, 687-694 (1961).

3. Gruoner, S., Untersuchungen über das Filzschrumpfverhalvenreinwollener Strickwaren beim Waschprocess in Trommel-waschmachinen, Textil-Ind. 72, 367-371 (1970).

4. Henning, H.-J., Töpert, H., and Valk, G. Einfluss von Um-fangs-geschwindigkeit, Höhe des Flottenstandes und Trom-mel-Flotten-verhältnis der Trommelwaschmaschine auf die

Filzschrumpfung von Wolle, Z. ges. Textilind. 68, 104-108(1966).

5. Horowitz, A., Investigation into the significance of the Pre-wash or Soaking in Cylinder Washing Machines, Konsum-entinstitutet meddelar No. 17, 42-48 (1967).

6. Liljemark, T., Åsnes, H., and Kärrholm, M. The Sensitivityof Cotton Fabrics to Wrinkling During Changing MoitsureRegain and its Dependence on Setting and Cross-LinkingParameters, Textile Res. J. 41, 526-533 (1971).

7. Schmidt, H. Über den Einfluss der Wäschebewegung aufWaschwirkung und Faserabtrieb in Trommel-Waschmasch-inen, Wäscherei-teknik und chemie 12, 549-553 (1959).

8. Swanepoel, O. A. and van Rooyen, A. Machine Washing ofWool, Textile Res. J. 40, 516-520 (1970).

9. Taube, K. R., Ross, E. S., and Poole, N. D. Use of modernHome Laundry Equipment, parts I and II, Amer. DyestuffRept. 50, 468-479 (1961); ibid. 51, 2-24 (1962).

10. Vaeck, S. V. and Maes, E. C. La mesure de l’intensité de

l’agitation des machines à laver, Teintex 35, 601-614 (1970).11. Viertel, O., Untersuchungen über das Waschen pflegeleichter

Textilien aus Polyester/Baumwolle im Haushaltwasch-vollautomaten und Trocknen im Haushalttrockner, Chemie-fasern 20, 494-496 (1970).

12. Wilkinson, P. R. and Hoffman, R. M. The Effects of Wearand Laundering on the Wrinkling of Fabrics, Textile Res. J.27, 632-660 (1959).

AlanuscriQt received Aforell .i, 1972. 1 .

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