Laundering

Please find some information below on common problems that occur in Industrial Laundering.

 

Please find some information below on common problems that occur in Industrial Laundering.

Colour change

All fabrics will lose some colour after processing. The greatest degree of shade change will occur between original and wash 1. The reason for this is because the ”wash off’ process involved in range dyeing cannot replicate in terms of time and mechanical action the severity of a machine washing. Accordingly, some loose dyestuffs can still remain. The shade change from wash1 through many washes afterwards will be more gradual.

Cotton rich fabrics will lose colour at a greater rate than polyester rich fabrics. This is principally due to the fact that cotton, being a weaker fiber than polyester, breaks more easily, taking colour away with it to reveal the inner part of a yarn which has less dye coverage.

Faded garments may not always be the result of excessive colour loss. It may be due to colour masking i.e. some contamination, which in essence covers the original colour.

QUESTIONS

• Were the garments properly classified? Light colours should not be mixed with darks and lightly soiled garments should not be mixed with those that are heavily soil The residuals from the darker dye stuffs and heavy soiling will mask the original colour of the other garments.

• Was optical brightener used in the wash process? Optical brightener should only be used for whites as they will give a faded appearance if used with col Most built detergents used today for colours contain optical brightening agents which increases the potential for this type of masking.

• Did the wash temperature exceed 85°C? Temperatures above this will negatively affect colour

• Did the wash process involve the use of chlorine? A chlorine wash will lead to substantial colour loss on fabrics, which utilize sulphur, reactive or poor quality vat dyes to colour cotton

• Yellowing Was the alkalinity necessary to remove oil based stains effectively neutralised in the rinse process? If not, yellowing will result when the garments are dri Were the garments over – dried? If so, yellowing or scorching will occur.

• Greying Was the wash cage cleaned before garments were introduced? Unclean wash cages used for oily rags can grey whites or dull colours.

 

 

Creasing / wrinkling (wash & wear) 

Cotton rich garments require greater attention than polyester rich garments in order to minimise creasing or wrinkling.

After tunnel finishing, garments with long, smooth panels and few seams will have a superior appearance to more stylish garments that include more features and seams.

Short garments such as shirts, tunics and lightweight jackets may not have sufficient weight in them to avoid wrinkling after tunnel finishing. Longer, heavier garments will shed wrinkles more easily.

Loosely constructed fabrics such as satins will shed creases more easily than dense constructions.

Crease recovery is facilitated in polyester rich garments if they are hot head pressed beforehand by the garment maker. Hot head pressing is nowadays very uncommon because of its expense with garment makers utilising steam presses instead. The recovery from creasing after tunnel finishing is inferior using these types of press.

QUESTIONS

• Was the wash cage over-loaded? If the wash cage is more than two thirds full, garments may not move freely and creases can be

• After the main wash, was the cool down process too fast? Too fast a cool down can have the effect of setting The reduction in temperature should be a maximum 4°C per seven minutes.

• If the garments were tunnel washed, was the press extraction at too high a pressure? The maximum pressure should be 12 bar, the minimum 8

• Were the garments over-dried? Over drying will wrinkle fabri Tumble driers should be loaded to no more than two-thirds capacity for effective wrinkle removal and cooled garments should be removed and hung immediately.

 

 

Pilling

The entangling of fibers during washing, dry cleaning or in wear to form pills which stand proud of the surface of a fabric and which are of such density that light will not pass through them (so they cast a shadow).·Textile Institute.

Surface pills will negatively influence the aesthetic value of a textile and is a major reason for the ultimate rejection of a garment by a wearer. In particular pilling can be evident in textiles produced from short staples of a number of different fibre types when subjected to significant friction and abrasion. It can be particularly evident in places exposed to high mechanical stress such as collars, which can rub against beards, armpits or in the crotch area of garments. Accordingly, correct garment design and appropriate sizing of garments and individuals will help minimise the formation of pills.

With respect to polyester cotton blended fabrics, the fibre that remains on the surface of the fabric is principally polyester and not cotton as often believed. Cotton breaks more readily and will shed from the fabric. Accordingly, polyester rich fabrics are more susceptible to pilling than cotton rich.

The type of yarn will also have a bearing on the amount of visible pilling. Ring spinning imparts a twist into a yarn, embedding tightly the fibre into that yarn. However, when the polyester fibre comes free from a yarn due to friction, part of it can remain trapped within the yarn because of the tightness. Consequently, pills on the surface of the fabric can remain, resulting in a poor appearance

Open end yarns are not as tight as ring spun yams. Consequently, polyester fibre is not trapped as tightly within the yarn as is the case with a ring spun yarn. Through friction, polyester fibre will more easily free itself totally from a yarn, resulting in a smooth surface appearance.

Fabric construction is also a major factor in determining the propensity of a fabric to pill. Very dense constructions allow for less yarn movement than more open constructions. This will reduce the amount of friction yarns receive, which in turn helps keep the fibre within the yarn.

In conclusion, within a polyester / cotton or cotton rich fabric, the blend of fabric, the type of yarn and type of construction are all important in determining the propensity of a fabric to pill.

In addition to garment styling and sizing, the working environment and the way the garment is laundered are also major factors in determining the level of pilling found on a fabric. When confronted with comments or complaints about pilling, you will find below examples of the types of question you can ask in return to understand better a particular situation.

QUESTIONS

• Localised or uniformly over the garment?

 

Localised pilling results from the heavy or continuous rubbing of a specific area e.g. collar, armpits, knees. Accordingly, for best results, garments should not be too tight so that some cushioning against rubbing occurs. Also, heavy belts or shoulder straps from bags etc. can lead to serious localised pilling.

Uniform pilling usually results from the mechanical and chemical damage caused by the wash process. However, you should also be aware that fabric surfaces can exhibit foreign pills, i.e. small knots of fibre formed from other fabrics. This can often result when garments are cleansed in dirty equipment or when mixed inappropriately with garments of other fibre types.

• Are the wash cages under – loaded? The optimum load is two thirds of This gives adequate room for maximum mechanical action for cleansing efficiency. Under­ loading will increase the mechanical action on the garment, increasing the possibility of fibre break-out.

• Is the water level adequate? A low water level lessens the cushioning effect on garments, increasing the likelihood of fibre break – The ratio of garments I water ( Kg I Litres ) should be 1:7 for an effective main wash and between 1:8 – 1:1O for rinsing.

 

NB.THE TREND IN LAUNDERING IS TO REDUCE LIQUOR RATIOS TO 1:3, 1:4 FOR WASHING AND 1:5 FOR RINSING IN ORDER TO SAVE ON COSTS. THIS WILL CREATE ADDITIONAL FRICTION ON GARMENTS, INCREASING THE LIKELIHOOD OF PILLING.

• Are softeners or anti-static agents used? Excessive amounts increase the propensity for fabrics to

• Are the garments evenly rotated or pooled at the end user? A poor rotation of garments or pooled garments invariably means that some garments within a contract receive more wear than others leading to the impression that variable quality is being

Chemical damage. Certain chemicals if allowed to settle on the fabric or if not properly removed after washing can damage fibres. Accordingly, garments should not be allowed to soak for long periods in enzyme baths. Furthermore, where chlorine bleach is used, it must be followed by an anti – chlorine application during rinsing.

 

 

Shrinkage 

All fabrics are susceptible to a degree of shrinkage. Most shrinkage occurs in the first few washes and then will continue over the garment’s lifetime but at a decreasing rate. Cotton rich fabrics will shrink progressively more than polyester rich fabrics of equal weight and construction. It should be noted that the vast majority of shrinkage takes place in the warp or length direction of a garment.

Apparent shrinkage problems may stem from garments not meeting garment makers’ specifications. This is almost certainly the case when very high apparent shrinkage is seen. At a laundry, it may well be worth measuring some unwashed garments found in the stores (the same styles as those against which the complaints arise) to see if they meet the manufacturers’ specifications. It is not unusual for some to be deficient.

Excessive shrinkage is usually the result of garments being over-dried:

• What was the moisture content of the garment prior to entering the tunnel finisher? It should be between 30 – 40% of its

What was the drying temperature when measured on the garment? It should never exceed 160°C. Optimum tunnel temperature is between 145 – 155°C and that of a tumble drier between 60 – 75°C. No garments should remain in the tunnel or the tumble drier when already dry i.e. Finishing process should be completed at the moment garments become dry. Accordingly, ideally, garments of different fibre compositions and I or greatly differing weights should not be mixed in the same drying equipment due to diverse moisture levels and drying rates.