Bleached Fabric & Environmental Impact

Black Mohair Velvet Contemporary Chair
Black faux leather upholstery
Black faux leather upholstery

Most of us are familiar with household (chlorine-based) bleach, which is sodium hypochlorite. It is a very powerful bleaching agent and, like similar agents used in the industrial bleaching of fabrics, it has by-products that include; dioxins, furans and organochlorides.

An alternative to a chlorine based bleach is Hydrogen Peroxide (H2O2). This has medical uses and domestic uses such as for bleaching hair.

Hydrogen peroxide occurs naturally by the action of sunlight on water and is simply water plus an extra oxygen molecule (2 lots of H20 plus one lot of 02 equals 2 lots of H2o2 for all you chemists). Hydrogen peroxide is quite reactive¬†and so easily gives up some of its oxygen to revert back to water. This act of giving up oxygen to something else, like fabric, causes the fabric or impurities in it to be oxidised. The oxidised parts of the fabric are chemically changed and lose their colour. They remain there but their colour is changed. That’s what makes it a bleach and so the end products are just the oxidised fabric and water.

Natural linen has a light brown or beige colour. To go lighter than this it has to be either bleached, or bleached and dyed.

If your clients are environmentally conscious and concerned about the environmental impact of the products they buy from you, it would be prudent to ensure that your linen is hydrogen peroxide bleached rather than chlorine bleached.

Fabric Treatment Companies – FR Flameproofing

silk velvet upholstery fabric textile FR Martindale RubsWe are often asked to recommend farbic treatment companies for flame retarding in contract installations. Most treatment comapanies offer other services such as; back coating fabric for walls, and stain resistance/repellency. There are several such companies in the UK and at various times we have used all of the following:

Essex Flameproofing,

Textiles FR, and

TEK Treatments

Just click the company name to take you to their web site. Please feel free to add comments to this posting recommending any suppliers you have used but any negative comments about other companies are not permitted on this site. Thank you.

What is fabric sanforisation, sanforised, sanforising?

interior design oxford rogue designs
Image by rogue-designs via Flickr

Sanforising is a finishing technique for already woven fabric.

Interior Designers do not need to know the detail of exactly what happens. So, in brief, the process is usually associated with cotton fabric and often also with shirting fabric. The idea behind sanforising is to pre-shrink the fabric. Clearly any shrinkage after the fabric has been made up may cause problems and Interior Designers DO need to be aware of that!

When sanforised fabric is subsequently made up into curtains or used on upholstery the naturally occurring effects of fabric stretching are reduced, but like many natural fabrics some further shrinkage could occur.

Click To Read More Interior Design Articles
Click To Read More Interior Design Articles

As a general rule: more tightly woven fabrics tend to shrink less.

The sanforisation process involves stretching and heating damp fabric over a series of rollers

Moleskin Upholstery Fabric

Moleskin Upholstery FabricMoleskin Fabric is an unusual fabric for upholstery, usually associated with clothing. KOTHEA moleskin is a premium moleskin specifically designed for upholstery with Martindale Rubs between 20,000 and 30,000. Moleskin is often a blend of cotton and linen; however KOTHEA‘s 100% cotton moleskin is extremely tightly woven ensuring that a luxurious look and feel is guaranteed. The overall look is similar to suede yet more exclusive and durable.

Fabric Tips #10

Interior Designers are sometimes asked for the environmental credentials of their specification. Here are some figures that give you an idea of the greenness of different yarns used in fabric production. The figures show the energy consumption (per kilo in KWH) required to make the fibres. Of course this is far from the total carbon footprint of the finished delivered and fully made up cushion or sofa or curtain. But it is a starting point often covering the more energy intensive part of the process.

17 Wool
27 Viscose
32 Polypropylene
35 Polyester
69 Nylon

Clearly natural wool wins hands down!

As a side note, the “Campaign For Wool” should start to get media coverage throughout the rest of 2010 with the patronage of HRH Prince Charles. The society of British Interior Design are planning to give wool a big push “All we are saying is…give fleece a chance”. Their tagline. Great! Well it made me laugh!

Cashmere throws – bespoke / custom sizes

To supplement our range of coloured cashmere throws (147 x 183 cm), we now have the ability to weave 100% cashmere throws in any size up to a maximum width of 220cm in off-white and natural colours.

Our hand woven linen throws (pictured) can also be woven in bespoke dimensions, to order.

Dyes and Pigments in Fabric

A Brief History of Natural Dyes (Mordants)

A dye is a substance that gives colour to fabric. Usually in a way such that washing, heating or lighting does not change the colour greatly.

Dyes tend to be carbon based (ie organic in a chemical sense) whereas pigments are very fine powders ‘disolved’ in a liquid. Pigments generally give brighter colours and are man-made.

Dyes have existed for at least 4000 years and, before 1850, were almost entirely from natural sources such as plants, trees and lichens but also sometimes from insects. Here are some natural dyes, rarely used today, and their sources:

1. Yellow
Seeds, stems and leaves of the weld plant
The inner bark of the North American oak ‘quercetin’
Dried petals of false saffron (safflower)

2. Red
Crushed insect bodies from Coccus (cochineal) or it’s distant relation Kermes.

3. Blue
From indigo or woad

4. Purple
From the medium sized predatory sea snail ‘commonly’ known as Murex.

5. Black
From the middle wood of the Logwood tree. This is still used today to dye silk and leather and is combined with Chromium. I have written other articles about how this ‘natural’ dye is one of the most damaging to the environment because of the use of chromium.

The art of the dye was historically a closely guarded secret with practitioners having their formulae to produce the colours and to retain them by the addition of various metal salts.

Cotton could not be directly dyed whereas wool and silk could. To add a dye to cotton the cotton had to be first treated with salts made from aluminium (red), magnesium (violet), tin, calcium (purple-red), copper, barium (blue) and iron (black-violet) and then dyed. These salts are called mordants.

The Start Of Synthetic Dyes

In the 1850s Chromium was found to give superior dye retention and so started the decline of the natural dye. Chromium mordants are still widely used for wool and less so for silk and nylon.

More precisely, the first commercially successful dye was ‘mauve’ discovered in England in 1856 and taken to market the following year. It was only sold for about 7 years but that was sufficient to start the dramatic decline of natural dyes and the investment in the science for newer and better dyes.

The Chromium discovery meshed well with the Industrial Revolution. The massively growing textile industry in Europe required a cheap and predictable manufacturing process. Natural dyes and mordants could require up to 20 steps in production, the colour could be variable and the dyes had to be transported unreliably from around the world. Because of these factors and the development of chemical science it is easy to see how by-products of coal tar extraction & coke production, abundant in Europe, became the foundation of the modern dye industry.

By 1900 nearly 90 percent of industrial dyes were synthetic.

Pre-war (WWI) Germany dominated the commercial dye market accounting for 90% of all output. Many German scientists worked with distilled cemicals from coal tar, an abundant by-product of the industrial revolution at the time. The German succes was probably due to their investment in the scientific method and in training scientists themselves. Some further ‘by-products’ of the research include aspirin and saccharin.

After WWI the industry gravitated to Britain (ICI), the USA and Switzerland, also moving away from coal tar to petroleum based research.

Perhaps only now with the ‘green’ movement are we seeing a resurgence of interest in natural dyes. KOTHEA cautions the environmentally conscious reader to look carefully at claims of dyes to be natural. Whilst they may well be made from natural materials the processes used along the way can be VERY damaging to the environment.

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