Upholstery Linen

Upholstery Linen Chair Bibendum Eileen Gray

LinenPinksUntil recently the finest linen was made exclusively in Western Europe. Whilst many of those producers still exist, much production has been shifted to the Far East. At KOTHEA, we endeavour to use European linen partly for sentimental reasons as we love the fabrics our mills have continued to deliver to us but also becuase the enviornmental impact of them is good and the quality fantastic.

Many of our natural linens are hydrogen peroxide bleached which is less environmentally damaging than the traditional use of the stronger chlorine-based bleach. Then, when colour is required, we typically only use dyes from natural materials.

Linen

Elegant, beautiful, durable, this luxury fabric is the strongest of the vegetable fibres and has 2 to 3 times the strength of cotton. It is smooth, making the finished fabric lint free and ensures that it only gets softer and finer the more it is washed. Linen comes from flax, a bast fibre taken from the stalk of the plant. The lustre is from the natural wax content, with it’s colour ranging from creamy white to light tan. Linen does wrinkle but also presses easily when damp. Linen, like cotton, can also be boiled without damaging the fibre.

The decrease in use of linen may be attributed to the industrialisation of cotton production (a cheaper fibre), the increasing quality of synthetic fibers, and a decreasing appreciation of buyers for very high quality yarn and fabric. Very little top quality linen is produced now, and most is used in low volume applications like hand weaving, as an art material, or table and bed linens.

Although the actual growing of linen is free of the extensive spraying and use of pesticides used on cotton, it is the production process that can be environmentally damaging – the extensive water consumption and the chemicals and mordants used in the dying process. Our Eco linen is of the highest grade, is hand loomed in Latvia and is undyed. It is bleached using low impact hydrogen peroxide rather than chlorine. See also Dye and Bleach, above, for further details.

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.

Bleaching :: The Environmental Impact Of Fabric

We were recently asked about the impact of fabric bleaching on the environment.  We covered this in January <here>.

Basically, try to use unbleached fabric if you are concerned about environmental impact. The natural colour of some fabrics such as linen can be aesthetically pleasing but also variable. If the fabric is dyed it may also be bleached first. if it has to be bleached the best option is for hydrogen peroxide bleaching.

How to Lighten Fabrics

We were asked how to lighten fabrics.

We would not advise any of our customers to do this themselves as the results are unpredictable.

Essentially though to lighten a fabric you have to bleach it. Some yarns and some dyes can be significantly affected by bleach others very little. Sunlight too has a bleaching effect and its effect depends on the degree of colour fastness of the fabric.

KOTHEA sells a hydorgen peroxide bleached linen. We have already made a few posts about that <here>. this bleaching is the most environemtnally way of bleaching fabrics during production. This bleaching is used mostly to remove the natural colour from linen.

Lighten Faux Fur With Hydrogen Peroxide

We were asked: “Can you lighten a faux fur with hydrogen peroxide”.

You can guess the answer: try it out on a sample first or on  piece you won’t see. However to be honest I don’t think it would work on most faux furs.

Hydrogen peroxide is a relatively weak bleach. Typically it is used on natural materials like human hair or linen. Faux furs or fake furs are normally synthetic.

It depends on what exactly the faux fur is made out of, this could be a variety of compounds. It might work on one or two compunds but I doubt it will have much of an effect on most.

Synthetic Dyes and Their Development

If you’re reading this you’ve probably already read my very brief history of natural dyes. The rest of the following discussion is not quite so brief and does get quite technical in a chemical sense but I’ve tried to omit as much of that as possible to make the information accessible to normal readers like you and me.

Within the space of 50 years mankind had changed almost totally from natural dyes to synthetic ones. Phase 1 of this change was the addition of Chromium. The subsequent, often parallel, phases are discussed below with a bias towards how they apply to fabrics.

The 8 subsequent developments of synthetic dyes from Chromium onwards are:
(1. Chromium)
2. Triphenylmethane dyes
3. Anthraquinone dyes
4. Xanthene and related dyes
5. Azo dyes
6. Reactive dyes
7. Phthalocyanine compounds
8. Quinacridone compounds
9. Fluorescent brighteners

Phase 2: Triphenylmethane dyes

In 1858 Verguin (France) discovers ‘fuchsine’ a rose coloured dye made from aniline and tin chloride. This was the first of a series of dyes later called Triphenylmethanes and this marked the second phase of the growth of the synthetic dye industry. Adding excess aniline made aniline blue. Soon other variations were discovered and the chemistry understood; and before 1900 several hundred colours had been documented.

One problem with these dyes was solubility. That was overcome by the addition of sulphuric acid.

Phase 3: Anthraquinone dyes

In the 1850s and 1860s the understanding of how carbon is structured (tetravalency) led to scientists being able to plan how chemicals might react before doing the experiments. Alizarin and its derivatives (the anthraquinones) gave a huge number of dyes which constitute the second biggest grouping of dyes.

The addition of sulphur created a group of bright, fast dyes for wool. Indrathone blue, a brilliant blue vat dye, was discovered at the turn of the century and related compounds are still today used as pigments spanning colours from blue to yellow.

Phase 4: Xanthene related dyes

Fluorescein was discovered in 1871 but related discoveries were seldom used with fabrics until the late 1880s when some were used for silk. However the dyes had poor lightfastness and usage was stopped – only to be re-used 70 years later when they were found to be particularly good on acrylic fibres. Better products have been found since and now only one chemical dye in this class is used commercially (Safranine T).

Phase 5: Azo dyes

These form more than half of the commercial dyes used today.

The key is the reaction of nitrous acid with arylamine and then with phenols and aryl amines. This chemical reaction forms part of the production process of 50% of dyes in use today having been used since 1875, firstly for wool.

Methyl- related azo dyes were used extensively up until the 1970s but this has now stopped in many countries as they were carcinogenic.

The discovery of the azo dyes led to the development of method called ingrain dyeing. Here the dye is ‘made’ within the fabric. Since the process was carried out at around freezing point, some dyes were called ice colours. In 1912 Naphtol was found to form a water-soluble compound with an affinity for cotton, a major step in the development of the ingrain dyes. Naphtol is able to form a great number of possible end colours although many of these are not adequately colourfast.

Other Azo dyes became the most important commercial colorants because of their wide colour range, good fastness properties, and tinctorial strength (colour density), which is twice that of the anthraquinones, the second most important group of dyes. Azo dyes are easily prepared from many readily available, inexpensive compounds and meet the demands of a wide range of end uses. Cost advantages tend to offset the fact that these are less brilliant and less lightfast than the anthraquinones.

Phase 6: Reactive dyes

Reactive dyes are very adaptable and can create a huge number of colours.

The first reactive dyes utilized monoazo for bright yellow and red shades. Adding aniline gave the azo dye used in the first Procion Red.

Dichlorotriazinyl dyes are now produced by more than 30 dye manufacturers, since the early patents on these dyes have expired.

With the introduction of reactive dyes, cotton could finally be dyed in bright shades with azo dyes for yellows to reds, with anthraquinones for blues, and with copper phthalocyanines for bright turquoise colours.

Phase 7: Phthalocyanine compounds

Phthalocyanines, the most important chromium derivatives developed in the 20th century being introduced in 1934 and marketed as Monastral Fast Blue B and Monastral Fast Blue G.

Copper phthalocyanine is the most important and can be formed directly on cotton. Although not useful for PET and acrylics, some complexes are utilized with nylon. Chemical bleaching alters the shade to bluish-green and green.

Water-soluble versions were developed later by the introduction of sulphur based chemicals also producing a direct dye for cotton (Chlorantine Fast Turquoise Blue Gll), the first commercial phthalocyanine dye.

Such colourants all display strong, bright blue to green shades with remarkable chemical stability. These compounds exhibit excellent lightfastness, and their properties are in striking contrast to those of natural pigments that are destroyed by intense light or heat and mild chemical reagents. The high stability, strength, and brightness of the phthalocyanines render them cost-effective, illustrated by the wide use of blue and green labels on many products.

Phase 8: Quinacridone compounds

A second group of pigments developed in the 20th century were the quinacridone compounds. Quinacridone itself was introduced in 1958. Its seven crystalline forms range in colour from yellowish-red to violet.

Phase 9: Fluorescent brighteners

Raw natural fibres, paper, and plastics tend to appear yellowish because of weak light absorption. Bleaching can reduce this but the bleach must be mild to avoid damaging the material. Alternatively a bluing agent can mask the yellowish tint to make the material ‘appear’ whiter (hence the phrase a ‘bluey whiteness’), or the material can be treated with a fluorescent compound that weakly emits blue visible light. These compounds, also called “optical brighteners,” they are not dyes in the usual sense. The major industrial applications are as textile finishers, pulp and paper brighteners.

Well done for getting this far!

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