Types of Fibres & Characteristics

Cotton

Cotton is a white or brownish-white, soft absorbent fibre composed of 90% to 96% cellulose. It grows from the see of the cotton plant. Cotton can retain 20% of its weight in moisture before saturation. It accepts a variety of dye types and can be extremely colourfast. For this reason, cotton lends itself well to contact dying processes, such as printing. Conversely, cotton is easily dyed by many staining materials, especially those containing acid dyes.

Cotton withstands high water temperature, but caution must be exercised because of its absorbent nature. Rapid drying is key to proper cleaning without problems. Cotton my be damaged or dissolved by concentrated mineral acids, such as hydrochloric, hydrofluoric, nitric and sulphuric acids. Dilute solutions of 3% or less may be used with no adverse effects if properly rinsed. Concentrated volatile organic acids, such as acetic or formic acids, do not affect cotton; however, nonvolatile organic acids, such as oxalic or critic acids, weaken the fibre (especially if hot) if not properly neutralised with appropriate alkaline agents.

Cotton easily withstands weak alkalis. Cold dilute solutions of chlorine bleach (sodium hypochlorite) does not harm cotton, however; it not neutralised with an antichlor, chlorine may cause slow degradation. Likewise, hydrogen peroxide (3%) and sodium perborate does not harm cotton if properly controlled. Reducing agents, such as sodium bisulfate or sodium hydrosulfide, has little effect on the fibre, but dye may be affected. Always test before using oxidising or reducing agents.

Linen

Linen is a fine, soft, silky, somewhat brittle vegetable fibre produced by retting the stems of the flax plant. The fibre is grey, brown, or tan in colour. Linen undergoes a comprehensive manufacturing process before it becomes a finished fabric.

Linen withstands high water temperature. Its ability to absorb moisture and then release it quickly makes it easy to clean. Concentrated mineral acids such as hydrochloric, hydrofluoric, nitric and sulphuric acids will damage the fibre, but dilute solutions (3% or less) may be used if properly neutralised and rinsed. Concentrated volatile organic acids, such as acetic or formic acids, do not adversely effects linen. However, non-volatile organic acids, such as oxalic or critic, weakens the fibre (especially if hot), if not properly neutralised.

Linen withstands weak alkalis, and cold, highly diluted solutions of chlorine bleach (sodium hypochlorite) will not harm it, unless left unneutralised, in which case the fibre slowly degrades.

The older the linen fabric, the more likely it is to brown while drying. Dyes used on linen may not withstand high alkalinity or chlorine bleach without colour loss. Hydrogen peroxide (3%) and sodium perborate do not damage linen and are less likely to harm dyes if properly controlled. Dilute reducing agents, such as sodium bisulfite or sodium hydrosulfide have little effect on the fibre itself, although dyes may be affected. Careful testing is imperative.

Linen is much more brittle then cotton. Carefully inspect it for any signs of abrasion, particularly in heavy-use areas such as cushions, armrest, headrest, and on pipping. Agitation during cleaning may have to be limited to avoid fibre damage.

Wool

Wool is a term used primarily to designate sheep hair. It consists of approximately 50% carbon, 23% oxygen, 16% nitrogen and 4% sulfur. Wool is an opaque (nontransparent), tri-component fibre consisting of an epidermis, cortex, and medulla.

Wool is flexible, elastic, strong and resilient. Depending on the yarn type and weave, it is very resistant to wear and abrasion. Wool absorbs up to 30% of its weight in moisture before it becomes saturated. It is easily contact dyed and therefore is easily stained by acid dyes (e.g. red wines, fruit juices). Wool swells in the presence of moisture. This enables it to release soil rapidly with the use of proper pre-conditioners and dwell time. Wool is somewhat weaker when wet and because of its tendency to felt, agitation applied during cleaning must be accomplished with care. High-pH cleaners damage wool fibres may cause dyes to bleed. Cleaning chemicals pH must be in the 5.5 to 8.5 range for cleaning wool.

Wool is naturally flame and wrinkle resistant, although it degrades when exposed to high temperature for extended periods. Common dry cleaning solvents such as aliphatic or chlorinated hydrocarbons, do not damage wool. As with any protein fibre, the use of any chlorine bleach (sodium hypochlorite) must be avoided.

When using an oxidising bleach on wool for specialised spotting or restorative cleaning, never exceed (3%) solution of hydrogen peroxide, and then only after thoroughly testing to avoid dye and or fibre damage. Dilute reducing agents, such as sodium bisulfite and hydrosulfide, may used effectively on wool. Careful testing highly recommended.

Silk

Silk fibre is obtained by unreeling the cocoons of silkworms. It is bicomponent fibre consisting of two strands of fibroin (80%), which are adhered with sericin or silk gum (20%), Silk is among the strongest, most elastic, consistency lustrous and expensive textiles fibres. Silk has the ability to stretch as much as 20%. Use caution when stretching silk fabric. raw silk is produced when the moth is allow to hatch from the cocoon, resulting in a staple fibre.

Silk absorbs as much as 30% of its weight in moisture before reaching saturation and it accepts dye quite easily; therefore, it may stain just as easily. Silk can withstand high temperatures, but it yellows in the presence of high alkalinity. Like wool it becomes brittle with extended exposure to either high alkalinity or acid soils. Use extreme caution when working on heavy-use areas or spots on silk furniture during cleaning. Like wool, Silk is easily damaged by chlorine bleach. Weak solutions (3% or less) of hydrogen peroxide or dilute reducing agents, such as sodium bisulfite and hydrosulfide, can be used fore stubborn stain removal, but only after careful testing to ensure that neither dye nor fibre is adversely affected.

Rayon

Rayon is a man-made, semi-synthetic fibre. Rayon like cotton; absorbs about 205 of its weight in moisture, but is more resistant to sunlight and microorganisms than cotton. It is not very elastic and does not regain its shape or size when stretched aggressively. Rayon loses up to 70% of its strength when its wet; therefore, minimising agitation and excessive moisture during cleaning is highly recommended. Rayon pile velvets can be extremely sensitive, and must be groomed as the cleaning process progresses. For the best results, each section must be groomed immediately after cleaning.

Rayon is also sensitive to heat, so reduce cleaning solutions temperatures when cleaning. Rayon is attacked by mineral acids, but is not affected by concentrated volatile organic acids, such as acetic or formic acid. However, non-volatile organic acids, like oxalic or citric acid, adversely affects the fibre, especially if hot and not properly neutralised. Rayon withstands weak alkalis. Use strong alkalis only when they are cool. Chlorine bleach (0.5% sodium hypochlorite), hydrogen peroxide (3%) or sodium perborate does not damage rayon, if properly used and neutralised. Reducing agents, such as sodium bisulfite or sodium hydrosulfide have little effects on the fibre itself. However; these products must be tested for dye compatibility.

Acetate

Acetate is an ester of cellulose, cellulose acetate. Acetate fibre resist wrinkling, stretching and shrinkage for most part; however, they lose some strength when wet, though not as much as rayon. Acetate is fairly moisture resistant and does not deteriorate from salt )in perspiration) or microorganism exposure.

Acetate has poor abrasion resistance, is heat sensitive, and is weakened by prolonged exposure to sunlight. Acetate fibres dissolve in acetone, alcohol or glacial acetic acid. Even nail polish or acetone-based nail polish remove or perfume can dissolve or degrade the acetate fibre. Mild solutions of hydrogen peroxide (3%) or very mild dilute chlorine bleach (less then 0.5% sodium hypochlorite), may be used. Use caution when testing acetate, since strong solutions of alkalis or acids can damage the fibre over time.

Nylon

Nylon is a man-made synthetic fibre and derived from coal, natural gas or petroleum products. Nylon is a polyamide formed from hydrogen, nitrogen, oxygen, and carbon. Nylon is very light and strong. These characteristics do not diminish with age. Therefore, nylon is very abrasion resistant. It can be stretched up to 33% of its length and still return to its original configuration. These characteristics make nylon fairly easy to clean, regardless of the type of weave. However, its is contact dyed by substances containing acid dyes, such as red wine or fruit juice, grape juice, coffee and tea.

Nylon is fairly heat resistant and not affected by alkalis that mat be present in pre-conditioners or rinse detergents. However, nylon may be dissolved by concentrated solutions of mineral acids, such as hydrochloric, sulphuric, or nitric acids. It is easily dissolved in formic acid. It resists most bleach and reducing agents. It is recommended that only dilute solutions of sodium hydrosulfide or hydrogen peroxide (3%) be used. Ue these chemicals only after extensive testing for colourfastness.

Polyester

Polyester is a man-made synthetic fibre and derived from coal, natural gas or petroleum products. Polyester manufacturing steps are similar to those for nylon. Polyester is strong and abrasion resistant. It does not stretch well, and thus is dimensionally stable. Spotting and cleaning results are excellent. Polyester resists sunlight, absorbs little moisture and dies quickly.

Polyester fibres are extremely difficult to stain; however they are oleophillic, that is, they attract oily soils that may yellow over. Polyester is fungus resistant and unlike nylon it responds well to mild bleaching. It has excellent resistance to weak alkalis and moderate resistance to strong ones. Polyester has good resistance to both mineral and organic acids, and excellent resistance to oxidising and reducing agents. As with any fibre or dye, it is recommended that testing be accomplished prior to spotting and cleaning.

Acrylic

Acrylic is a thermoplastic fibre derived from the petroleum products acetylene or ethylene. Acrylic is not as strong as other synthetics or even cotton, but is stronger than wool. It has moderate resistance to abrasion and does not stretch well.

Acrylic has the ability to resist both water and oil-based stains because it is not absorbent. it is resistant to sunlight and high temperatures, and it resists fungus growth. It has good resistance to weak alkalis. However this resistance decrease as the temperature, strength of the alkalis and dwell time increase. Acrylic is extremely colourfast and resists both mineral and organic acids, because of the way acrylic is dyed, both fibre and dye solutions are seldom affected by normal bleaching, normal testing before spotting or cleaning is highly recommended.

Polypropylene (Olefin)

Polypropylene is developed through the polymerisation of propylene has with the aid of metal compound, such as titanium chloride. Polypropylene is water-resistant fibre. It absorbs less then 0.1% of its weight in moisture. It is one of the lightest fibres and is very sensitive to high heat. It is about as strong as nylon or polyester, but less abrasion resistant. Its lack of absorbency makes it very difficult to dye, so it is solution dyed exclusively, which makes it virtually stain proof, even when exposed to red wine, fruit juice, coffee and tea or other materials containing acid dyes.

Like polyester, Polypropylene is oleophillic and attracts oily soils, which may cause yellowing over time. Prolonged exposure to sunlight deteriorates the fibre to the point of disintegration. It is resistant to fungi and classified as chemically inert. It has excellent resistance to alkalis and acids, and bleaches safely (0.5% to 1% solution of sodium hypochlorite).