Flame Retardant Polyester Fabric in the Laundry

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Information Specific to MAT 4 care instructions.

This information has been compiled by Mr Graham Jowsey, in association with Materialised Pty Ltd. Graham is the principal consultant with his own consulting company which specialises in laundry and linen service operations and all areas associated with hospital textile requirements.

From April 1971 to July 1990 Graham was employed by the NSW Department of Health as its Laundry Consultant, responsible for coordinating the activities of all the hospital laundry/linen service facilities in NSW. During this time he was also instrumental in developing the group linen service concept in NSW and the introduction of healthcare textile standards and specifications throughout the state.

Graham has been the Chairman of Standards Australia Healthcare Textiles Committee TX/15, since it was first established in 1981 and has coordinated the development and promulgation of the textile standards produced by this committee. TX/15 was responsible for the publication in 1989 of the Australian Standard for curtains and patient bed screens for hospitals and institutions, AS3717.   In addition, Graham was Chairman of the technical sub-committee of TX/16 which is the Standards Committee currently developing standards for laundry procedures and practices.

Introduction

This information was written because these new technology fabrics require slightly different handling in the laundry than the traditional cottons we are so accustomed to using. Polyester fibre is in many ways far more durable than other fibres, but in other ways more sensitive to how it is handleds especially in laundry situations. This brochure is intended as an aid in better understanding man-made fibres and the way they perform like they do. Most of all it is written so all of us in the industry, can reach our ultimate goal,

“A SAFE ATTRACTIVE INTERIOR ENVIRONMENT”.

General

Flame retardant textiles are to be found wherever there is a greater need for care and protection. These specialist fabrics help to lessen the risk of fire and to reduce its severity so that major catastrophes can be avoided. Due to these factors, flame retardant textiles are being increasingly used by hospitals and institutions in those areas considered to have a high flammability risk. In particular, hospitals and institutions are using flame retardant materials for curtains and patient bed screens, as the use of vertical hanging textiles for these purposes creates a potential danger for initial flame ignition and flame spread from floor to ceiling

There are many types of flame retardant textiles on the market today which derive their performance features from either chemical finishes on the fabric or inherent fibre properties.

It is generally considered that, providing the flame retardant materials can be conveniently laundered and processed correctly, the inherently flame retardant fabrics are preferable as they overcome the concerns usually related to the long term durability of coated and impregnated chemical finishes.

Polyester staple fibres and filament yarns have been developed to provide inherently and permanent flame resistant textiles that also possess the general characteristics of normal polyester.  These modified FR Polyesters are marketed under a variety of brand names.

Polyester is a very strong, elastic fibre which has high abrasion resistance, good durability and exceptional dimensional stability. It is unaffected by dilute or medium concentrated mineral acids and has good resistance to hot or cold dilute alkalis. Polyester produces easy care fabrics that have excellent resistance to light, natural drapability and good crease resistance properties.

Therefore, when the basic polyester properties are combined with a permanent flame retardant the resultant fabrics are an ideal choice for curtains and bed screens.

The permanent flame retardant property of FR Polyester goes right though the fibre and is achieved by incorporating an organophosphoric compound directly linked into the polyester polymer chain so that it cannot be removed.

FR Polyester textiles are produced in a variety of colours, weights and designs to suit every style and mood and yet all the variety of fabrics comply with the required Australian Standard AS 1530 Part 2 and 3 Building Standard for flammability and also Australian Standard AS3789.9, Textiles for health care facilities and institutions – curtains and patient bed screens – Fabric performance properties.

 

Care Instructions

To provide the best means of laundering FR Polyester fabrics the following care instructions are provided as suggested guidelines on which to develop the most successful processing methods so that the fabric’s characteristics are consistently retained.

Hospital curtains and bed screens have to be laundered and reprocessed on a regular basis, so as to be thermally disinfected and cleaned for aesthetic purposes. It is of paramount importance that all textiles of a ‘special’ nature can be processed successfully through industrial laundry facilities in a manner that is convenient to the laundry and cost effective in both the short and long term.

FR Polyester fabrics can be laundered in a similar manner to hospital uniforms, which are usually manufactured from 65% Polyester/35% Cotton fabrics, and in many instances industrial laundries have already adopted a “uniform wash system” for processing hospital curtains and bed screens. However local consideration needs to be given to ‘drying’ FR Polyester fabrics so as to minimises laundry processing and while still providing the best possible finish for the products being processed.

1. Sorting

On receipt of soiled laundry from a hospital or institution the first step is to separate the items according to the degree of soil condition and fabric composition. The FR Polyester fabrics should be separated from any heavy, greasy soiled articles and, where possible, they should be processed together in full loads due to the fabrics particular wash performance and drying characteristics.

 

This classification process is carried out to save giving the lightly soiled fabrics the heavy soiled wash formulae, and also because the polyester fibres have a particular attraction for all oils and greases. In a mixed soiled load any oil in the washing machine not held in suspension by detergent will be attracted to the polyester fibres and remain there as ‘redeposition’.

 

Polyester fibres are known as being oleophilic (oil loving) and very susceptible to redeposition which is one of the most difficult types of soiling to remove. In addition, if FR Polyester is washed with all cotton articles there will be a tendency for the polyester fabric to attract lint and the load may come out linty.

2. Washing

When washing polyester articles it is recommended that the washing machine is underloaded to minimise the problem of creasing. Underloading by up to 25% may be beneficial in an open pocket machine but up to 50% may be necessary in some pocket-type machines.

Overloading of a washing machine can give rise to a form of creasing known as pressure creasing. This is often mistaken for thermal shock creasing with a result that time can be wasted attempting to rectify the problem by paying attention to the cooldown stage. Pressure creasing is characterised by creases extending along the weave direction rather than in a randomised distribution.

The laundering of FR Polyester fabrics also requires the selection of specially formulated detergent compounds. These types of wash chemicals are usually blended from non-ionic or anionic detergents, silicates and phosphates which provide excellent detergency without the high levels of alkalinity usually found in standard wash formulas. In washing there are three things that work together to remove the soil: ie, water level, water temperature and wash chemicals.

It is important to have a balance between these three items so that the best overall performance can be achieved.

Most hospital and commercial laundries usually wash bed screens and curtains in a uniform wash cycle which has hot wash temperatures of around 60 degrees C. However, to comply with current thermal disinfection guidelines it is necessary to wash at 70 degrees C for a minimum of 10 minutes and for hospital work in particular this criteria needs to be built into the appropriate wash cycle.

Polyester fabrics are strongly susceptible to thermal shock creasing caused by rapid cooling during washing and wrinkles put into the fabric in this way are extremely difficult to remove later, therefore a controlled lowering or cooldown sequence needs to be incorporated into the wash cycle, particularly after the hot wash and during the rinsing stages. When processing polyester fabrics it is essential to cool down the load gradually after a hot wash to a temperature where thermal shock creasing is not likely to occur, and before adding cold rinse water in quantity. Fabric temperatures must be below 60 degrees C before extracting or before cold rinsing occurs.

 

Cooldown can be achieved in two ways. The preferable method involves slow addition of cold water to the machine with weired overflow to achieve a final temperature of 60 degrees C at a maximum reduction rate of 6 degrees C per minute.

The alternative method involves the slow addition of cold water giving the temperature decrease at the same maximum rate but allowing the dip to rise. Intermediate dumping of liquor to drain may be necessary in this procedure.

After washing, the load should be hydroextracted briefly so that the residual moisture content of the fabric is about 30-40%. The duration of high speed extraction must be limited to avoid pressure creasing. One minute extraction at high speed is frequently sufficient to achieve the required residual moisture content.

A suggested wash cycle for processing FR Polyester fabrics is summarised as follows:

 

* If bleaching is required to remove stubborn stains then it is recommended that Hydrogen Peroxide is used (1mL per kg) during the Hot Wash stage 5 and the temperature is increased to 80 degrees C. In these instances care should be taken with subsequent cooldown process.

3. Drying

After washing and hydroextracting, the FR Polyester fabrics can be either tumbled dry or finished through an ironing machine.  For easy care and best results it is generally recommended that the Fabrics are tumbled dry and folded.

When tumble drying is used the polyester fabrics should again be underloaded to the same degree as in the washing machines, ie, between 25-50%. When a drier is overloaded it does not give the load a proper tumbling action and air circulation as the articles are packed so tightly in the cylinder. The result of this is unequal drying in the load and wrinkles on the fabrics.

 

Temperature is also important when drying 100% polyester fabrics as the load should only be dried to an exhaust air temperature of 80 degrees C.

Proper cooldown in the tumble drier is also very important and the fabrics should be cooled down to room temperature by ventilating in a rotating drum before the drier is turned off. When the drier has stopped the load should be pulled out immediately and the fabrics folded as soon as possible.

In addition the laundry baskets should not be overloaded as the fabrics will become wrinkled, particularly if they are left overnight, and it is then very difficult to get these wrinkles out.

 

If the laundry prefers to dry and finish the FR Polyester fabrics by high speed calendering, then care should be taken to avoid overdrying of the polyester. If this cannot be achieved by increasing the ironer speed, it may be necessary to modify the extraction stage of the wash process (to deliberately increase the moisture retention) or to lower the ironer temperature. Overdrying of the polyester causes rejection into the first bed of the ironer and a creasing and concertina-fold effect on the fabrics. Heavier fabrics which hold more residual moisture than lighter fabrics are easier to process through the ironing machines.

Due to the potential problems that can occur by finishing the FR Polyester fabrics through ironing machines the manufacturers of the fibre, Hoechst, recommend that for the best appearance and easy care reliability the fabrics are tumbled dry and folded.

4. Drycleaning

FR Polyester fabrics can be drycleaned with perchlorethylene or fluorocarbon solvents under easy care conditions.

 

MAT 4

  • Warm wash, tumble dry at moderate temperature, ramping down to cool
  • Moderate Iron
  • Dry Clean 30
  • Possible shrinkage 3%
  • IMPORTANT: DO NOT WASH OR DRY WITH ANY OTHER ARTICLES.

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