Definition of Nonwoven Fabric | Raw Materials for Producing Nonwoven | Types of Nonwoven

Nonwoven fabrics are those made by bonding, adhesive application, chemical and mechanical treatment. It is clear that a nonwoven is something that is not woven. Nonwovens are unique engineered fabrics which offer cost effective solutions as e.g. in hygiene convenience items, or as battery separators, or filters, or geotextiles, etc.

•  Different Types of Woven Fabrics
•  Knitting Technology

Definition of Nonwoven Fabric: These are made from fibres, without any restriction, but not necessarily from fibres. A manufactured sheet, web or batt of directionally or randomly orientated fibres, bonded by friction, and/or cohesion and/or adhesion, excluding paper and products which are woven, knitted, tufted, stitch-bonded incorporating binding yarns or filaments, or felted by wet-milling, whether or not additionally needled. The fibres may be of natural or man-made origin. They may be staple or continuous filaments.

Properties of Nonwoven: 

• Absorbent
• Abrasion resistance
• Breathable
• Durable
• Flexible
• Drapeable
• Hydrophobic
• Processability
• Resilient
• Soft & stable
• Mouldable
• Temperature resistant
• Flame resistant
• Lint-free
• Wrinkle resistant
• Water repellent
• Tear resistant
• Low price

Uses of Nonwoven:

Household : Gown wipes and dusters, table cover, tea and coffee bags, bed clothing, fabric softeners, food wraps, pillow case, filters, bed and table linen, etc.
Medical: personal care and hygiene as in baby diapers, surgical operation coat, products for femine hygiene, adult products, wipe, lab coat, dry and wet pads, nursing pads, sanitary napkin.
Garments: Interlinings, insulation and protective clothing, workwears, chemical defence products etc.
Automotive textiles: Boot liners, shelf trim, oil and cabin air filters, moulded bonnet liners, heat shields, airbags, tapes, decorative fabrics, etc.

Geotextiles: asphalt overlay, soil stabilization, drainage, sedimentation and erosion control, etc.
Industrial: filtering cloth, industrial cloth, roof material, cable insulation, roll goods, reinforced plastics, air conditioning, cement wrapper, coating, geomembrane, industrial wipe.
Agriculture： Sprout cultivation cloth, warming drape, etc
Microfibre nonwovens, such as Amaretta or Alkantara, are being used increasingly as high-quality furnishings  for seat upholstery fabrics, on covered components, for the door lining, and/or for the headliner.
Others: Healthcare, like operation drapes, gowns and packs, face masks, dressings and
swabs, osteomy bag liners, home furnishing, leisure and travel, school and office etc

Raw Materials for the Production of Nonwovens:
Nonwovens are textile fabrics consisting of separated fibres which are arranged properly by means of special technologies. For this reason the choice of fibres and possibly bonding materials is of special importance.

Usually all kinds of fibres can be used to produce nonwoven bonded fabrics.
The choice of fibre depends on
– the required profile of the fabric and
– the cost effectiveness
To produce nonwoven bonded fabrics
– chemical fibres of both cellulosic and synthetic origin as well as
– natural fibres and
– inorganic fibres
are mainly used

Types of Nonwoven Fabrics:
Nonwovens are usually classified depending on their fibrous material as well as making technique.

• CWashing(water-repellent) nonwoven
• Thermal-bonding
• Air-laid
• Wet nonwoven
• Spun-bond
• Melt-brown
• Needle-punching 
• Stitch-bonded

Definition of Nonwoven Fabric | Raw Materials for Producing Nonwoven | Types of Nonwoven

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Nonwoven fabrics are those made by bonding, adhesive application, chemical and mechanical treatment. It is clear that a nonwoven is something that is not woven. Nonwovens are unique engineered fabrics which offer cost effective solutions as e.g. in hygiene convenience items, or as battery separators, or filters, or geotextiles, etc.

•  Different Types of Woven Fabrics
•  Knitting Technology

Definition of Nonwoven Fabric: These are made from fibres, without any restriction, but not necessarily from fibres. A manufactured sheet, web or batt of directionally or randomly orientated fibres, bonded by friction, and/or cohesion and/or adhesion, excluding paper and products which are woven, knitted, tufted, stitch-bonded incorporating binding yarns or filaments, or felted by wet-milling, whether or not additionally needled. The fibres may be of natural or man-made origin. They may be staple or continuous filaments.

Properties of Nonwoven: 

• Absorbent
• Abrasion resistance
• Breathable
• Durable
• Flexible
• Drapeable
• Hydrophobic
• Processability
• Resilient
• Soft & stable
• Mouldable
• Temperature resistant
• Flame resistant
• Lint-free
• Wrinkle resistant
• Water repellent
• Tear resistant
• Low price

Uses of Nonwoven:

Household : Gown wipes and dusters, table cover, tea and coffee bags, bed clothing, fabric softeners, food wraps, pillow case, filters, bed and table linen, etc.
Medical: personal care and hygiene as in baby diapers, surgical operation coat, products for femine hygiene, adult products, wipe, lab coat, dry and wet pads, nursing pads, sanitary napkin.
Garments: Interlinings, insulation and protective clothing, workwears, chemical defence products etc.
Automotive textiles: Boot liners, shelf trim, oil and cabin air filters, moulded bonnet liners, heat shields, airbags, tapes, decorative fabrics, etc.

Geotextiles: asphalt overlay, soil stabilization, drainage, sedimentation and erosion control, etc.
Industrial: filtering cloth, industrial cloth, roof material, cable insulation, roll goods, reinforced plastics, air conditioning, cement wrapper, coating, geomembrane, industrial wipe.
Agriculture： Sprout cultivation cloth, warming drape, etc
Microfibre nonwovens, such as Amaretta or Alkantara, are being used increasingly as high-quality furnishings  for seat upholstery fabrics, on covered components, for the door lining, and/or for the headliner.
Others: Healthcare, like operation drapes, gowns and packs, face masks, dressings and
swabs, osteomy bag liners, home furnishing, leisure and travel, school and office etc

Raw Materials for the Production of Nonwovens:
Nonwovens are textile fabrics consisting of separated fibres which are arranged properly by means of special technologies. For this reason the choice of fibres and possibly bonding materials is of special importance.

Usually all kinds of fibres can be used to produce nonwoven bonded fabrics.
The choice of fibre depends on
– the required profile of the fabric and
– the cost effectiveness
To produce nonwoven bonded fabrics
– chemical fibres of both cellulosic and synthetic origin as well as
– natural fibres and
– inorganic fibres
are mainly used

Types of Nonwoven Fabrics:
Nonwovens are usually classified depending on their fibrous material as well as making technique.

• CWashing(water-repellent) nonwoven
• Thermal-bonding
• Air-laid
• Wet nonwoven
• Spun-bond
• Melt-brown
• Needle-punching 
• Stitch-bonded

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Regenerated/Semi-Synthetic Textile Fiber | Man-made Cellulose Fiber

Regenerated fibres are those made from natural fiber polymer, for example wood pulp or cotton linters. These raw materials are reformed to produce fibers or filaments suitable to spin into yarns. The first commercial regenerated synthetic fiber was rayon, also known as ‘artificial silk’, and was made from modified cellulose and wood pulp, later known as viscose rayon

• Natural Textile Fibers
• Manufactured Textile Fibers

Rayon was the first manufactured fiber, made into filaments through wet spinning. These are called regenerated cellulose fiber and the cellulose material used to produce these fibers are -Wood pulp, Cotton linters, Seed Hair, Bast, Leaf, Grasses and Bamboo pulp. Rayon fiber is classified into three types- Viscose rayon, Acetate rayon and Cuprammonium Rayon. These regenerated fibers are produced by dissolving cellulose chemically into solution and passed these concentrated viscous solution through spinneret. 

Viscose Rayon

Viscose was discovered by Cross and Bevan in 1892 during a programme of research on the general properties of cellulose. It is the sodium salt of cellulose Xanthate (Cell-O-C-SNa).It is may be manufactured from cotton linters but the usual starting point is wood pulp. The unrefined wood chips are purified by treatment first with calcium bi-sulphite and then by boiling with steam under pressure for about 14 hours.

Features of Viscose Fiber

• It is a semi-synthetic or regenerated cellulose fiber
• It is the first manufactured fiber.
• It has a serrated round shape with smooth surface.
• When it wets, losses it's strength up to 50%.
• It is also known as artificial silk.

Acetate Rayon

The secondary cellulose acetate rayon cotton linters, waste cotton or high-grade wood pulp is purified by boiling with alkali followed hypochlorite bleaching. After purification the cellulose is dried and mixed with acetic an-hydride and glacial acetic acid together with about 1% of sulphuric acid.

Features of Acetate Fiber

• It has luxurious feel and appearance.
• It has a strength of 1.4 kg per denier which falls to 0.9 when wet.
• First time this material is used as a protective coat for fabric wings of aeroplanes.
• Excellent drape ability and softness
• Shrink, moth and mildew resistant.

Cuprammonium Rayon

Cuprammonium rayon is made from scoured and bleached cotton linters or purified wood pulp with a high alpha cellulose content. The cellulose id washed and then pressed until it contains about 50 percent of water.

Features of Cuprammonium Fiber

• It is not unlike natural silk when examined under the microscope.
• Fibers are finer than other rayon's.
• This products have a particularly pleasing soft -like handle.
• Due to more amorphous region at the structure it undergoes degradation with greater range than natural cellulose

Other Regenerated Fibers that are under processing to get commercial Success

• Algin ALG
• Cupro CUP
• Rubber ED
• Lyocell CLY
• Modal CMD
• Triacetate CTA
• Viscose CV

Regenerated/Semi-Synthetic Textile Fiber | Man-made Cellulose Fiber

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Regenerated fibres are those made from natural fiber polymer, for example wood pulp or cotton linters. These raw materials are reformed to produce fibers or filaments suitable to spin into yarns. The first commercial regenerated synthetic fiber was rayon, also known as ‘artificial silk’, and was made from modified cellulose and wood pulp, later known as viscose rayon

• Natural Textile Fibers
• Manufactured Textile Fibers

Rayon was the first manufactured fiber, made into filaments through wet spinning. These are called regenerated cellulose fiber and the cellulose material used to produce these fibers are -Wood pulp, Cotton linters, Seed Hair, Bast, Leaf, Grasses and Bamboo pulp. Rayon fiber is classified into three types- Viscose rayon, Acetate rayon and Cuprammonium Rayon. These regenerated fibers are produced by dissolving cellulose chemically into solution and passed these concentrated viscous solution through spinneret. 

Viscose Rayon

Viscose was discovered by Cross and Bevan in 1892 during a programme of research on the general properties of cellulose. It is the sodium salt of cellulose Xanthate (Cell-O-C-SNa).It is may be manufactured from cotton linters but the usual starting point is wood pulp. The unrefined wood chips are purified by treatment first with calcium bi-sulphite and then by boiling with steam under pressure for about 14 hours.

Features of Viscose Fiber

• It is a semi-synthetic or regenerated cellulose fiber
• It is the first manufactured fiber.
• It has a serrated round shape with smooth surface.
• When it wets, losses it's strength up to 50%.
• It is also known as artificial silk.

Acetate Rayon

The secondary cellulose acetate rayon cotton linters, waste cotton or high-grade wood pulp is purified by boiling with alkali followed hypochlorite bleaching. After purification the cellulose is dried and mixed with acetic an-hydride and glacial acetic acid together with about 1% of sulphuric acid.

Features of Acetate Fiber

• It has luxurious feel and appearance.
• It has a strength of 1.4 kg per denier which falls to 0.9 when wet.
• First time this material is used as a protective coat for fabric wings of aeroplanes.
• Excellent drape ability and softness
• Shrink, moth and mildew resistant.

Cuprammonium Rayon

Cuprammonium rayon is made from scoured and bleached cotton linters or purified wood pulp with a high alpha cellulose content. The cellulose id washed and then pressed until it contains about 50 percent of water.

Features of Cuprammonium Fiber

• It is not unlike natural silk when examined under the microscope.
• Fibers are finer than other rayon's.
• This products have a particularly pleasing soft -like handle.
• Due to more amorphous region at the structure it undergoes degradation with greater range than natural cellulose

Other Regenerated Fibers that are under processing to get commercial Success

• Algin ALG
• Cupro CUP
• Rubber ED
• Lyocell CLY
• Modal CMD
• Triacetate CTA
• Viscose CV

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Scholarship/Financial Aid for Master of Science (M.Sc.) in Textile Engineering

M.Sc. or Graduate program of textile engineering department is not available across the world. Students of Subcontinent of Asia are completing their undergraduate degree from various native colleges as well as universities whereas they need to go for higher study. Masters in Textile Engineering or Ph.D. is not offered by many universities where students can study for higher degrees with or without pay. There are very few universities who offers for higher education on Textile whereas scope for scholarship is also very low. Now I am sharing three universities where you can apply for scholarship. 

Scholarship for Masters Program in Germany:

DAAD (Deutscher Akademischer Austausch Dienst) German Academic Exchange Service offers some postgraduate courses with special relevance to developing countries. Textile Machinery and High Performance Material Technology is a branch of the Faculty of Mechanical Science and Engineering of Dresden University of Technology offers this valuable degree where you can apply through DAAD. The university website for this department is SCHOLARSHIP FOR THE STUDY IN ITM . Very well qualified graduates (4 years) from any reputed university with at least 2 years of relevant work experience is required to apply for this program. Course duration will be 1 to 2 years where 750 Euro will be paid by the organization. A contemporary air fair will be paid to Bangladeshi Students to come and back to Germany from Bangladesh. IELTS and Computer skill with higher academic results will be added extra value for the international students. To know about application procedure you may visit the official website of DAAD Delhi and also get help from your nearest Goethe Institute or browse http://www.goethe.de/enindex.htm.

Scholarship/Financial Aid for Master of Science Program at Philadelphia University: 

Philadelphia is a reputed private university of United State where many graduates get opportunity to apply for financial aid as well as scholarship. M.S of textile education is available at this university where you can apply for scholarships. Philadelphia University is  committed to making a high-quality, professional education affordable for every qualified student. Since course completing cost is a concern therefore, they encourage students to apply for financial aid, regardless of family financial circumstances. Many of their graduate students receive aid in the form of loans, assistantships  as well as scholarships. You may be gone through IRS Tax Return Transcript Request service to make yourself a higher educative people in the field of textile. You may visit the official page of financial aid of this university.

Scholarship for Post Graduation on Textile at Kyung Hee University:

Kyung Hee University is a well reputed university of South Korea where M.S for textile is available. Two subjects like as Clothing & Textile and Advanced Polymer and Fiber Materials is available in this university for both M.S and Ph.D. program. To get scholarship as an International student you can contact with the professors of this department directly.  

Kap Jin Kim, Professor, Ph.D.
kjkim@khu.ac.kr

Joon Youl Lee, Professor, Ph.D.
jylee@khu.ac.kr

Jae Hyung Park, Assistant Professor, Ph.D.
jaehyung@khu.ac.kr

Scholarship/Financial Aid for Master of Science (M.Sc.) in Textile Engineering

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M.Sc. or Graduate program of textile engineering department is not available across the world. Students of Subcontinent of Asia are completing their undergraduate degree from various native colleges as well as universities whereas they need to go for higher study. Masters in Textile Engineering or Ph.D. is not offered by many universities where students can study for higher degrees with or without pay. There are very few universities who offers for higher education on Textile whereas scope for scholarship is also very low. Now I am sharing three universities where you can apply for scholarship. 

Scholarship for Masters Program in Germany:

DAAD (Deutscher Akademischer Austausch Dienst) German Academic Exchange Service offers some postgraduate courses with special relevance to developing countries. Textile Machinery and High Performance Material Technology is a branch of the Faculty of Mechanical Science and Engineering of Dresden University of Technology offers this valuable degree where you can apply through DAAD. The university website for this department is SCHOLARSHIP FOR THE STUDY IN ITM . Very well qualified graduates (4 years) from any reputed university with at least 2 years of relevant work experience is required to apply for this program. Course duration will be 1 to 2 years where 750 Euro will be paid by the organization. A contemporary air fair will be paid to Bangladeshi Students to come and back to Germany from Bangladesh. IELTS and Computer skill with higher academic results will be added extra value for the international students. To know about application procedure you may visit the official website of DAAD Delhi and also get help from your nearest Goethe Institute or browse http://www.goethe.de/enindex.htm.

Scholarship/Financial Aid for Master of Science Program at Philadelphia University: 

Philadelphia is a reputed private university of United State where many graduates get opportunity to apply for financial aid as well as scholarship. M.S of textile education is available at this university where you can apply for scholarships. Philadelphia University is  committed to making a high-quality, professional education affordable for every qualified student. Since course completing cost is a concern therefore, they encourage students to apply for financial aid, regardless of family financial circumstances. Many of their graduate students receive aid in the form of loans, assistantships  as well as scholarships. You may be gone through IRS Tax Return Transcript Request service to make yourself a higher educative people in the field of textile. You may visit the official page of financial aid of this university.

Scholarship for Post Graduation on Textile at Kyung Hee University:

Kyung Hee University is a well reputed university of South Korea where M.S for textile is available. Two subjects like as Clothing & Textile and Advanced Polymer and Fiber Materials is available in this university for both M.S and Ph.D. program. To get scholarship as an International student you can contact with the professors of this department directly.  

Kap Jin Kim, Professor, Ph.D.
kjkim@khu.ac.kr

Joon Youl Lee, Professor, Ph.D.
jylee@khu.ac.kr

Jae Hyung Park, Assistant Professor, Ph.D.
jaehyung@khu.ac.kr

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Types of Zipper | Metal, Coil & Vislon Zipper - Garments Manufacturing

Zipper is one of the main trims or trimmings for making garment. Zipper is used to garment for functional purpose as well as decorative purpose. Zipper is normally used to making pants and jackets. Denim garments frequently use zipper as it is bottom garment eventually some top garments to decorate it. For knit garments it is used for jacket making, some pull over, over coat as well as trousers sometimes.

Different types of zippers are available in world trade but they are mainly classified into three prime category. They are - 

• Metal Zipper
• Coil Zipper
• Vislon Zipper

These three types of zippers are available in different colors, different types of tape and different types of finishing.

 Standard Plastic Molded Vislon Zipper

  Multi Color Vislon Zipper

 Invisible Coil Zipper

 Standard Coil Zipper

Invisible Two tone Zipper

 Metal Zipper with Bottom Stopper

 Cotton Tape Metal Zipper

Elastic Tape Metal Zipper

Fancy Vislon Zipper

Aluminum Teeth Metal Zipper

Antique Gold Teeth Metal Zipper 

Antique Silver Teeth Metal Zipper 

Black Oxide Teeth Metal Zipper

Gold Finish Teeth Metal Zipper

Neon Color Tape Vislon Zipper

Types of Zipper | Metal, Coil & Vislon Zipper - Garments Manufacturing

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Zipper is one of the main trims or trimmings for making garment. Zipper is used to garment for functional purpose as well as decorative purpose. Zipper is normally used to making pants and jackets. Denim garments frequently use zipper as it is bottom garment eventually some top garments to decorate it. For knit garments it is used for jacket making, some pull over, over coat as well as trousers sometimes.

Different types of zippers are available in world trade but they are mainly classified into three prime category. They are - 

• Metal Zipper
• Coil Zipper
• Vislon Zipper

These three types of zippers are available in different colors, different types of tape and different types of finishing.

 Standard Plastic Molded Vislon Zipper

  Multi Color Vislon Zipper

 Invisible Coil Zipper

 Standard Coil Zipper

Invisible Two tone Zipper

 Metal Zipper with Bottom Stopper

 Cotton Tape Metal Zipper

Elastic Tape Metal Zipper

Fancy Vislon Zipper

Aluminum Teeth Metal Zipper

Antique Gold Teeth Metal Zipper 

Antique Silver Teeth Metal Zipper 

Black Oxide Teeth Metal Zipper

Gold Finish Teeth Metal Zipper

Neon Color Tape Vislon Zipper

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Important Fabric/Yarn Dyeing & Finishing Terms

In Wet Processing Technology where pretreatment, dyeing, printing and finishing areas have some important terms like as hydrolysis, hygroscopic/hydrophobic, Leuco Compound, M:L ratio, mordanting, pantone, PFD, reactivity/substantivity etc.This is my second post about textile dyeing terms. You can see the other terms to Textile Fiber, Yarn, Woven & Knit Fabric Dyeing Terms

Hydrolysis - The decomposition of a chemical by reaction with water. Some chemicals, such as MX dyes, are effectively destroyed by hydrolysis. Others, such as soda ash, are madeuseful because of hydrolysis. Hydrolysis will occur when susceptible compounds are in aqueous solution, but can also occur because of water absorbed from moist air, without the compound ever appearing wet or damp. This is why many dry chemicals must be kept in sealed containers.

Hygroscopic – Tendency to absorb water (usually meaning absorbing it from air). Some of the commonly used chemicals in dyeing are hygroscopic. If they are left exposed to moist air, they will absorb water from the air.

Ion - An electrically charged particle resulting from adding or removing electrons to an atom or a group of bonded atoms.

Ionic bond - A chemical bond as a result of electrical attraction between positive and negative ions; also called salt linkage. In ionic bonding, typically an electron is transferred from one atom to another, leaving one with a positive charge and one with a negative charge. These electrical charges produce strong attraction between the differently charged ions

Leuco - refers to vat dyes in the reduced form; in general a prefix meaning white Vat dyes are converted from the insoluble pigment form to the soluble leuco dye form by means of a reducing agent and an alkali, often sodium hydrosulfite and sodium hydroxide.

Level - Uniform in shade over the surface of a piece of dyed fabric or along the length of dyed yarn.

Light Fastness – This is a measure of how resistant a coloring material, such as dye, is to fading due to exposure to light.

Liquor ratio (M:L) – This is the ratio of the weight of the dyebath or other processing bath to the weight of the goods being dyed or processed.

Loom state - Fabric as it comes from the loom, usually unbleached, containing size, and maybe a bit dirty. Loom state is essentially synonymous with greige or grey.

Mercerization - Treatment of cotton yarn or fabric with a strong solution of sodium hydroxide; named after its inventor, John Mercer. Mercerizing cotton can significantly improve its dye uptake, especially if there are immature fibres present. Typically it is done using about 20% to 25% sodium hydroxide solution at around 20°C

Molecular weight - The weight of a molecule; the sum of all atomic weights of all the atoms in the molecule;

Mordant - a chemical that aids attachment of a dyestuff to fibres by bonding to both the fibre and the dye. A mordant must have high affinity for both the dye and the fibre, acting to attach the dyestuff to the fibre.

Padding - a dyeing method with very low liquor to goods ratio, where typically only enough strong dye solution is used to saturate the fabric. Padding can have the advantage of high dye yield.
.
Pantone - A company and its trademark. The Pantone Company produces a wide range of color guides useful in almost any industry dealing with color. The colors in the guide are widely accepted as standards. Colors are sometime seen described as a Pantone number: Pantone applies a unique number to each color.

pH - a measure of the concentration of hydronium (H3O+ , H+ attached to a molecule or water) in a solution. pH = -log[H30+ ] (that is, the negative base-10 logarithm of the concentration of hydronium) . Acids have pHs less than 7; bases have pHs greater than 7. A pH of 7 is neutral. The normal pH range is 0 to 14.

Pigment - A colored substance that is insoluble in water, usually in the form of a fine powder
Pigments are used to color many types of paint, including some textile paints, and almost all “inks” used for screen printing. Pigments need some sort of binder to hold them onto fabric.

Pigment dyeing - coloring fabric with pigments mixed with a binder; this term is considered to be improper, since‘ dyeing’ is generally restricted to application of colorants that are soluble, and pigments are insoluble

Precipitate - A precipitate has low solubility in the solution from which it was formed, giving a cloudy appearance, which sediments at the bottom of the solution.

Prepared For Dyeing (PFD) – These are the fabric or garment that is specially made to be dyed; sometimes “preferred for dyeing. PFD fabrics have been desized, scoured, and fully bleached, but have been processed without optical brighteners or softeners which can interfere with dye uptake. This fabrics are processed with cotton fabric as well as made with cotton sewing threads..

Reduction clearing - Removal of unfix dyes on the surface of fabric by use of a reducing agent.
Fine particles of disperse dye often remain on the surface of dyed fabric. These particles can cause wash
fastness problems, yet are hard to fully remove by washing alone. A mixture of about 2 grams per litre each of sodium hydrosulfite and sodium carbonate is used at about 70 degrees Celsius for about 20 minutes. Dye inside the fibre is not affected by this treatment.

Scour (Scouring) - Essentially, thoroughly washing fibers, yarn or fabric to remove contaminants such as oil, wax or any other impurities. Yarns and fabrics may be dirty, contain natural waxes or oils, or have been treated with size or lubricants used in spinning, weaving or knitting. Usually Alkali treatment is used to scour the substrates as well as this process is known as scouring.

Singeing - an industrial defibrillation process where rapidly-moving fabric passes over a flame or a very hot plate in order to burn away fibres poking up from the surface. To remove the projecting fiber from the surface of the fabric, passed through gas burner or roller is commonly known as singeing.

Size (Sizing) – The ingredient applied to yarns or fabrics to make them stiffer or temporarily bind fibers together. Sizing is used extensively, especially for cellulose fibers, to make them easier to process or protect them from damage during high-speed weaving.

Soaping - With respect to dyeing, the process of washing dyed fabric with very hot (often boiling) water with surfactants, rarely actually soap, to remove dye that is not fixed to the fiber.

Stripping - Removal of dye from fabric. Stripping is usually done with a reducing agent such as thiox, formosul or sodium hydrosulfite and often requires hot to boiling conditions. Some dyes are difficult to strip, and the result often is not white.

Stock solution - A solution of known strength, made up with the intent of dilution or mixing before final use. Stock solutions are a convenient way of avoiding the need to weigh chemicals each time you need to use some. For example, if you need 0.27 grams of Smurf extract in a blue dye formula, and you have a stock solution of 10% extract, you would measure 2.7 milliliters of stock solution to get that amount.

Sublimation - The conversion of a solid directly to a gas, without passing through a liquid phase
Some disperse dyes will sublime. This can make dyed fabric subject to fading due to heating, as from ironing at high temperature.

Substantive (Substantivity) - Tendency of a dye to move from a solution onto fibers in the solution
A dye that is substantive will leave the dye bath and be concentrated on the fiber in the bath. Without
substantivity, most of the dye would simply remain in solution or dispersion in the bath. Dye substantivity is generally associated with the molecular structure of the dye, and often big molecules have high substantivity, while small molecules have low substantivity.

Subtractive - with reference to color, removal of colors from light reflected from a surface
A surface that is illuminated by white light and that reflects all visible colors will appear white.

Tendering - Weakening of a fiber, normally meaning as a result of chemical degradation. Cellulose fibers can be tendered by acids or by excessive action of oxidative bleaches.

Union dye - A dye that is a mixture of two or more different classes of dye, used typically to dye blends of fibers.

Van Der Waals forces – Intermolecular forces as a result of localization of electrical charge within molecules. A molecule considered as a whole is electrically neutral. Because of the way in which electrons are held, there may be local areas that appear to have positive or negative electric charge, either permanently or temporarily. These charges lead to attraction between molecules. These forces are weak and easily broken, but they can be important in dyeing. They can be important in affinity, and hold dye molecules on the fiber near to where a much stronger bond may ultimately be formed.

Wash Fastness - A measure of the resistance of a dye to washing out of the fiber, yarn or fabric as well as garments. Wash fastness tests are concerned not only with loss of dye from the
colored fabric, but also transfer of dye from the wash liquor to other items.

Washing soda – (sodium carbonate) Washing soda, if “pure”, is usually sodium carbonate decahydrate (Na2CO3.10H20). Retail washing soda (Local Soda) contain additives such as detergents, salt and optical brighteners, and is therefore not a good substitute for soda ash for dyeing

Important Fabric/Yarn Dyeing & Finishing Terms

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In Wet Processing Technology where pretreatment, dyeing, printing and finishing areas have some important terms like as hydrolysis, hygroscopic/hydrophobic, Leuco Compound, M:L ratio, mordanting, pantone, PFD, reactivity/substantivity etc.This is my second post about textile dyeing terms. You can see the other terms to Textile Fiber, Yarn, Woven & Knit Fabric Dyeing Terms

Hydrolysis - The decomposition of a chemical by reaction with water. Some chemicals, such as MX dyes, are effectively destroyed by hydrolysis. Others, such as soda ash, are madeuseful because of hydrolysis. Hydrolysis will occur when susceptible compounds are in aqueous solution, but can also occur because of water absorbed from moist air, without the compound ever appearing wet or damp. This is why many dry chemicals must be kept in sealed containers.

Hygroscopic – Tendency to absorb water (usually meaning absorbing it from air). Some of the commonly used chemicals in dyeing are hygroscopic. If they are left exposed to moist air, they will absorb water from the air.

Ion - An electrically charged particle resulting from adding or removing electrons to an atom or a group of bonded atoms.

Ionic bond - A chemical bond as a result of electrical attraction between positive and negative ions; also called salt linkage. In ionic bonding, typically an electron is transferred from one atom to another, leaving one with a positive charge and one with a negative charge. These electrical charges produce strong attraction between the differently charged ions

Leuco - refers to vat dyes in the reduced form; in general a prefix meaning white Vat dyes are converted from the insoluble pigment form to the soluble leuco dye form by means of a reducing agent and an alkali, often sodium hydrosulfite and sodium hydroxide.

Level - Uniform in shade over the surface of a piece of dyed fabric or along the length of dyed yarn.

Light Fastness – This is a measure of how resistant a coloring material, such as dye, is to fading due to exposure to light.

Liquor ratio (M:L) – This is the ratio of the weight of the dyebath or other processing bath to the weight of the goods being dyed or processed.

Loom state - Fabric as it comes from the loom, usually unbleached, containing size, and maybe a bit dirty. Loom state is essentially synonymous with greige or grey.

Mercerization - Treatment of cotton yarn or fabric with a strong solution of sodium hydroxide; named after its inventor, John Mercer. Mercerizing cotton can significantly improve its dye uptake, especially if there are immature fibres present. Typically it is done using about 20% to 25% sodium hydroxide solution at around 20°C

Molecular weight - The weight of a molecule; the sum of all atomic weights of all the atoms in the molecule;

Mordant - a chemical that aids attachment of a dyestuff to fibres by bonding to both the fibre and the dye. A mordant must have high affinity for both the dye and the fibre, acting to attach the dyestuff to the fibre.

Padding - a dyeing method with very low liquor to goods ratio, where typically only enough strong dye solution is used to saturate the fabric. Padding can have the advantage of high dye yield.
.
Pantone - A company and its trademark. The Pantone Company produces a wide range of color guides useful in almost any industry dealing with color. The colors in the guide are widely accepted as standards. Colors are sometime seen described as a Pantone number: Pantone applies a unique number to each color.

pH - a measure of the concentration of hydronium (H3O+ , H+ attached to a molecule or water) in a solution. pH = -log[H30+ ] (that is, the negative base-10 logarithm of the concentration of hydronium) . Acids have pHs less than 7; bases have pHs greater than 7. A pH of 7 is neutral. The normal pH range is 0 to 14.

Pigment - A colored substance that is insoluble in water, usually in the form of a fine powder
Pigments are used to color many types of paint, including some textile paints, and almost all “inks” used for screen printing. Pigments need some sort of binder to hold them onto fabric.

Pigment dyeing - coloring fabric with pigments mixed with a binder; this term is considered to be improper, since‘ dyeing’ is generally restricted to application of colorants that are soluble, and pigments are insoluble

Precipitate - A precipitate has low solubility in the solution from which it was formed, giving a cloudy appearance, which sediments at the bottom of the solution.

Prepared For Dyeing (PFD) – These are the fabric or garment that is specially made to be dyed; sometimes “preferred for dyeing. PFD fabrics have been desized, scoured, and fully bleached, but have been processed without optical brighteners or softeners which can interfere with dye uptake. This fabrics are processed with cotton fabric as well as made with cotton sewing threads..

Reduction clearing - Removal of unfix dyes on the surface of fabric by use of a reducing agent.
Fine particles of disperse dye often remain on the surface of dyed fabric. These particles can cause wash
fastness problems, yet are hard to fully remove by washing alone. A mixture of about 2 grams per litre each of sodium hydrosulfite and sodium carbonate is used at about 70 degrees Celsius for about 20 minutes. Dye inside the fibre is not affected by this treatment.

Scour (Scouring) - Essentially, thoroughly washing fibers, yarn or fabric to remove contaminants such as oil, wax or any other impurities. Yarns and fabrics may be dirty, contain natural waxes or oils, or have been treated with size or lubricants used in spinning, weaving or knitting. Usually Alkali treatment is used to scour the substrates as well as this process is known as scouring.

Singeing - an industrial defibrillation process where rapidly-moving fabric passes over a flame or a very hot plate in order to burn away fibres poking up from the surface. To remove the projecting fiber from the surface of the fabric, passed through gas burner or roller is commonly known as singeing.

Size (Sizing) – The ingredient applied to yarns or fabrics to make them stiffer or temporarily bind fibers together. Sizing is used extensively, especially for cellulose fibers, to make them easier to process or protect them from damage during high-speed weaving.

Soaping - With respect to dyeing, the process of washing dyed fabric with very hot (often boiling) water with surfactants, rarely actually soap, to remove dye that is not fixed to the fiber.

Stripping - Removal of dye from fabric. Stripping is usually done with a reducing agent such as thiox, formosul or sodium hydrosulfite and often requires hot to boiling conditions. Some dyes are difficult to strip, and the result often is not white.

Stock solution - A solution of known strength, made up with the intent of dilution or mixing before final use. Stock solutions are a convenient way of avoiding the need to weigh chemicals each time you need to use some. For example, if you need 0.27 grams of Smurf extract in a blue dye formula, and you have a stock solution of 10% extract, you would measure 2.7 milliliters of stock solution to get that amount.

Sublimation - The conversion of a solid directly to a gas, without passing through a liquid phase
Some disperse dyes will sublime. This can make dyed fabric subject to fading due to heating, as from ironing at high temperature.

Substantive (Substantivity) - Tendency of a dye to move from a solution onto fibers in the solution
A dye that is substantive will leave the dye bath and be concentrated on the fiber in the bath. Without
substantivity, most of the dye would simply remain in solution or dispersion in the bath. Dye substantivity is generally associated with the molecular structure of the dye, and often big molecules have high substantivity, while small molecules have low substantivity.

Subtractive - with reference to color, removal of colors from light reflected from a surface
A surface that is illuminated by white light and that reflects all visible colors will appear white.

Tendering - Weakening of a fiber, normally meaning as a result of chemical degradation. Cellulose fibers can be tendered by acids or by excessive action of oxidative bleaches.

Union dye - A dye that is a mixture of two or more different classes of dye, used typically to dye blends of fibers.

Van Der Waals forces – Intermolecular forces as a result of localization of electrical charge within molecules. A molecule considered as a whole is electrically neutral. Because of the way in which electrons are held, there may be local areas that appear to have positive or negative electric charge, either permanently or temporarily. These charges lead to attraction between molecules. These forces are weak and easily broken, but they can be important in dyeing. They can be important in affinity, and hold dye molecules on the fiber near to where a much stronger bond may ultimately be formed.

Wash Fastness - A measure of the resistance of a dye to washing out of the fiber, yarn or fabric as well as garments. Wash fastness tests are concerned not only with loss of dye from the
colored fabric, but also transfer of dye from the wash liquor to other items.

Washing soda – (sodium carbonate) Washing soda, if “pure”, is usually sodium carbonate decahydrate (Na2CO3.10H20). Retail washing soda (Local Soda) contain additives such as detergents, salt and optical brighteners, and is therefore not a good substitute for soda ash for dyeing

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What is the difference between lining and interlining - Garments Manufacturing

Sometimes we confuse with lining and interlining in case of garments manufacturing. For making garments we frequently use these two materials to different types of cloths. At first we should clear, 

what is lining or interlining?

Lining: Piece of fabric which is used as the subsidiary fabric under main fabrication or shell fabric to make the garment useful for cold countries or as warm cloth. Usually knit fabric, Sherpa or Fleece fabric is used as lining. Lining is generally used to trouser, jacket, over coat, coat or any warm cloth at the main body, collar portion or at sleeve of a garment. Don’t confuse lining with padding which is another piece of material used as middle part of jacket as well as coat. Single jersey knit fabrics is used with denim fabric as lining where rib fabrics are frequently used at waist band or cuff at bottom of any trouser.

Interlining: It is one kind of trims that is used in between two layers of fabric in garments to reinforce and support as well as through controlling areas of garments and retain the actual shape of garments. This material attaches to garments through either sewing or heating arrangement. Two types of interlining are used in garments making and they are Fusible Interlining and Sewn or non fusible interlining. Fusible interlining is very popular due to many reasons where resin coating interlining is common and required temperature for fusible interlining is 160-170 degree centigrade. Iron machine you can use to attach the interlining with fabric but for bulk production you have to take help of fusing machine.

We can see from above two discussions that lining may be any kind of fabric attaching with main body fabric as extra whereas interlining is very fine piece of material used between two layers of fabric to reinforce and keep original shape of garments. Therefore, we are very clear that lining and interlining is totally two different material and their function as well as using areas are also different.

What is the difference between lining and interlining - Garments Manufacturing

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Sometimes we confuse with lining and interlining in case of garments manufacturing. For making garments we frequently use these two materials to different types of cloths. At first we should clear, 

what is lining or interlining?

Lining: Piece of fabric which is used as the subsidiary fabric under main fabrication or shell fabric to make the garment useful for cold countries or as warm cloth. Usually knit fabric, Sherpa or Fleece fabric is used as lining. Lining is generally used to trouser, jacket, over coat, coat or any warm cloth at the main body, collar portion or at sleeve of a garment. Don’t confuse lining with padding which is another piece of material used as middle part of jacket as well as coat. Single jersey knit fabrics is used with denim fabric as lining where rib fabrics are frequently used at waist band or cuff at bottom of any trouser.

Interlining: It is one kind of trims that is used in between two layers of fabric in garments to reinforce and support as well as through controlling areas of garments and retain the actual shape of garments. This material attaches to garments through either sewing or heating arrangement. Two types of interlining are used in garments making and they are Fusible Interlining and Sewn or non fusible interlining. Fusible interlining is very popular due to many reasons where resin coating interlining is common and required temperature for fusible interlining is 160-170 degree centigrade. Iron machine you can use to attach the interlining with fabric but for bulk production you have to take help of fusing machine.

We can see from above two discussions that lining may be any kind of fabric attaching with main body fabric as extra whereas interlining is very fine piece of material used between two layers of fabric to reinforce and keep original shape of garments. Therefore, we are very clear that lining and interlining is totally two different material and their function as well as using areas are also different.

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Textile Fiber, Yarn, Woven and Knit Fabric Dyeing Terms

Woven or knit fabric dyeing terms such as affinity, antichlor, shade, bonding, electrolyte, exhaustion, fixation, griege, hardness etc are very important for wet processing technology learning as well as engineering students. Some of them I have been used to describe here.

Affinity – The attraction between two items, in dyeing affinity essentially means the preferential attraction of the dye for the fibre rather than for the solution of the dye-bath. A dye with high affinity readily leaves the dye solution of dispersion to attach to the fiber being dyed.

Anion - A negatively charged ion. Many chemicals used in textile processing are described as anionic. This means that when the chemical ionizes in solution, the ion that is “functional” has a negative electrical charge. Most dyes are anionic. Surfactants, including some used as fabric softeners, may be anionic (others are cationic or non-ionic).

Anhydrous (without water) - Many “dry” chemicals may contain some water as part of the crystal structure. Although this can often be compensated for in making up formulas, it is often more convenient to use chemicals that contain no water, that is, that are anhydrous.

Antichlor – This is a chemical used to neutralize chlorine bleach. It can be very difficult to completely rinse chlorine bleach out of fabric. The residual bleach can interfere with subsequent dyeing as well as it will eventually damage the fiber. A rinse in a solution of antichlor, most commonly sodium bisulfite, will quickly neutralize the bleach. Hydrogen peroxide also functions to neutralize chlorine bleach. On the other hand for neutralization of chlorine in water used to make up dye baths, sodium thiosulfate is the preferred antichlor agent.

Auxochrome – The groups which are associated to dyestuff’s chemical structure refer to the color increasing group.

Batch or Batching - leaving goods saturated with dye solution for some period of time, typically hours, and typically at “room temperature” for the dye to fix to the fibre

Boil – Usually, to heat or maintain a solution at the temperature where the vapor pressure of a liquid equals atmospheric pressure, that is, its boiling point; in dyeing sometime called “atmospheric boil” to distinguish from boiling under pressure.

Bond – Basically three types of bond are there, which are hydrogen bond, ionic bond, covalent bond and another thing is there which is van der Waals forces. From these bonds hydrogen bonds are weakest, ionic bonds intermediate in strength, and covalent bonds are strongest. Van der Waals forces are something of a special case.

Carbonizing – It is the treatment of wool with acid (Sulphuric Acid), followed by partial drying and
heating to remove plant materials.The hot acid will degrade or ‘carbonize’ bits of plant matter in the wool, so that it is easily removed by subsequent mechanical methods.

Cation - A positively charged ion. Many chemicals used in textile processing are described as cationic, meaning that when the compound ionizes in solution, it is the positively charged ion that is “functional”.

Chromophore – It is color-bearing compound, typically meaning the part of a larger organic molecule that makes it appear colored. Dyes typically have a chromophore chemically bonded to other structures that impart desired characteristics such as affinity for the fibre and solubility in water. A particular chromophore structure may be found in a variety of dye classes and in pigments.

Color Index - a joint publication of the Society of Dyers and Colourists in Britain and the American Association of Textile Chemists and Colorists. The Colour Index contains information on dye structures, classifications, manufacturers and processes.

Covalent bond - a chemical bond where a pair of electrons is are shared relatively equally between two atoms in the compound. Covalent bonds are formed between the fibers and reactive dyes. These are the strongest type of chemical bond,and are responsible for the excellent wash fastness of reactive dyes.

Crocking - Transfer of color from dyed or pigmented fabric by rubbing to a cloth name crocking cloth. Wet crocking refers to transfer of color from a piece of dyed fabric to another piece of fabric, or to an undyed area of the same fabric, while the fabric is wet. Dry crocking means the same, except that the fabric is dry.

Density - As a measure of physical properties of a substance, the ratio of the mass (weight) of the substance to its volume.

Depth of shade - Ratio of weight of dye to weight of goods dyed, usually expressed as percentage. Depth of shade (DOS), in these terms, is not really a very good way of comparing the darkness or intensity of color of finished fabrics, due to inherent differences in the hues of different dyes within a family, differences between dye families, and differences due to the nature of the fabric. Dye manufacturers’ shade cards are typically show one or two depths of shade for a particular dye, often between 1% and 4%, except for black, which is typically 3% to 6%.

Desizing - Desizing is an important step prior to dyeing fabric which is done to remove size materil from fabric, since size can interfere with dye uptake. Some size materials wash out easily. Starch is commonly used for size, and can be quite difficult to remove. Amylase enzymes are often used industrially for starch removal. Some sizes can be readily removed by hot water washing.

Dope Dyeing - Coloration of the polymer prior to manufacture of the fibre.This is really a misnomer, since the colorants are almost always pigments: “mass pigmentation” is a more accurate term. Some synthetic polymers such as polypropylene cannot be dyed after being made into fibres, and coloration by adding pigments to the melted material is the only method available. Pigmenting prior to making fibres can also produce washfastness and lightfastness that is higher than can be obtained with any dyeing process.

Dye Activator - One dye seller’s name for an alkali intended for use with reactive dyes; believed to be pure soda ash. This term is somewhat misleading: in the case of most reactive dyes on cellulose fibers, it is the fiber, not the dye, that is “activated” (an exception to this is vinyl sulfone dyes).

Electrolyte – This is a substance that makes an electrically conductive solution when it is dissolved in water. Electrolytes dissociate to form ions in solution. Fibers immersed in water develop a negative electrical charge at their surface. Most dyes are anionic, so the fiber tends to repel the dye. The presence of electrolytes in the dye bath helps to overcome this repulsion so that the dye can gain access to the surface of the fiber. The most common electrolyte in dyeing is sodium chloride (common salt). Sodium sulfate is used sometimes. The acids used with acid dyes also behave as electrolytes.

Exhaust Dyeing - Generally meaning the use of a dye bath of moderately large liquor to goods ratio, in which the fiber is immersed for some time, allowing the dye molecules to leave the bath and attach to the fibers. Exhaust dyeing is the typical process for most commercial fabric dyeing. It depends of dye substantivity.

Exhaustion – It is the leaving of a dye from the dye bath and attachment to the fibre being dyed. The ideal dye would exhaust totally - all the dye in the dye bath would end up on the fibre. Exhaustion is sometimes specified as a percentage. For example, 60% exhaustion would mean that 60% of the total amount of dye has attached to the fiber, and 40% is still in solution. Reactive dyes generally show moderate exhaustion while many acid dyes exhaust to the point that the dye liquor becomes nearly colorless.

Fixation – It is formation of the “final” bond between the dye and fiber. The bond type formed between the fiber and the dye varies with the type of dye and the fiber. As examples, reactive dyes fix by covalent bonding while acid dyes fix by a variety of mechanisms such as ionic bonding and hydrophobic forces. Disperse and vat dyes are fixed in the fiber largely by physical entrapment of insoluble dye within the fiber.

Fixative - In dyeing, a chemical that helps improve wash fastness of dyed fabric. Some types of dye do not bond strongly to fibers, and will wash out over time. Fixatives applied after dyeing can help, although some will degrade light fastness or cause shade changes.

Formosul – It is a trade name for sodium formaldehyde sulfoxylate.

Fuchsia – This is a bluish-red color named after a flower named after Herr Fuchs.

Glass Transition Temperature - The temperature above which a material changes from a brittle,“glassy” nature to a rubbery nature; on cooling, the material changes back to glassy Synthetic fibres, such as polyester and nylon show this change of physical character. The rate of dye uptake increases dramatically when the fiber is near or above the glass transition temperature. If the glass transition temperature is above the boiling point of water, as it is with polyester, the dyeing rate is extremely slow even at the boil.

Greige – It means the grey stage of fabric or the fabric used to dyeing. In North America, greige is often used to describe loom state fabric that is unbleached, contains size and lubricants, and may be a bit dirty. Greige goods are made ready for dyeing by singeing, desizing, scouring and usually bleaching.

Hand Feel -   the feel of a fabric through hand. Hand of a fabric is quite subjective, and often difficult to describe. Both chemical and mechanical treatments are frequently used to alter the hand of a fabric. To increase hand feel of fabric softener is used usually.

Hardness - With respect to water, a measure of the content of minerals that impart certain properties.
Calcium and magnesium ions are main cause of hardness in  water. They can interfere with some chemical processes in preparation and dyeing.

Hydrogen bond – It is the weakest chemical bond in which hydrogen that is already covalently bonded to one atom is electrically attracted to a lone pair of electrons on another atom. Some atoms such as oxygen are said to be very electronegative, which means that they strongly draw bonding electrons toward themselves. If hydrogen is bonded to such an atom, the hydrogen “appears” to have some positive charge.

Textile Fiber, Yarn, Woven and Knit Fabric Dyeing Terms

No comments

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Woven or knit fabric dyeing terms such as affinity, antichlor, shade, bonding, electrolyte, exhaustion, fixation, griege, hardness etc are very important for wet processing technology learning as well as engineering students. Some of them I have been used to describe here.

Affinity – The attraction between two items, in dyeing affinity essentially means the preferential attraction of the dye for the fibre rather than for the solution of the dye-bath. A dye with high affinity readily leaves the dye solution of dispersion to attach to the fiber being dyed.

Anion - A negatively charged ion. Many chemicals used in textile processing are described as anionic. This means that when the chemical ionizes in solution, the ion that is “functional” has a negative electrical charge. Most dyes are anionic. Surfactants, including some used as fabric softeners, may be anionic (others are cationic or non-ionic).

Anhydrous (without water) - Many “dry” chemicals may contain some water as part of the crystal structure. Although this can often be compensated for in making up formulas, it is often more convenient to use chemicals that contain no water, that is, that are anhydrous.

Antichlor – This is a chemical used to neutralize chlorine bleach. It can be very difficult to completely rinse chlorine bleach out of fabric. The residual bleach can interfere with subsequent dyeing as well as it will eventually damage the fiber. A rinse in a solution of antichlor, most commonly sodium bisulfite, will quickly neutralize the bleach. Hydrogen peroxide also functions to neutralize chlorine bleach. On the other hand for neutralization of chlorine in water used to make up dye baths, sodium thiosulfate is the preferred antichlor agent.

Auxochrome – The groups which are associated to dyestuff’s chemical structure refer to the color increasing group.

Batch or Batching - leaving goods saturated with dye solution for some period of time, typically hours, and typically at “room temperature” for the dye to fix to the fibre

Boil – Usually, to heat or maintain a solution at the temperature where the vapor pressure of a liquid equals atmospheric pressure, that is, its boiling point; in dyeing sometime called “atmospheric boil” to distinguish from boiling under pressure.

Bond – Basically three types of bond are there, which are hydrogen bond, ionic bond, covalent bond and another thing is there which is van der Waals forces. From these bonds hydrogen bonds are weakest, ionic bonds intermediate in strength, and covalent bonds are strongest. Van der Waals forces are something of a special case.

Carbonizing – It is the treatment of wool with acid (Sulphuric Acid), followed by partial drying and
heating to remove plant materials.The hot acid will degrade or ‘carbonize’ bits of plant matter in the wool, so that it is easily removed by subsequent mechanical methods.

Cation - A positively charged ion. Many chemicals used in textile processing are described as cationic, meaning that when the compound ionizes in solution, it is the positively charged ion that is “functional”.

Chromophore – It is color-bearing compound, typically meaning the part of a larger organic molecule that makes it appear colored. Dyes typically have a chromophore chemically bonded to other structures that impart desired characteristics such as affinity for the fibre and solubility in water. A particular chromophore structure may be found in a variety of dye classes and in pigments.

Color Index - a joint publication of the Society of Dyers and Colourists in Britain and the American Association of Textile Chemists and Colorists. The Colour Index contains information on dye structures, classifications, manufacturers and processes.

Covalent bond - a chemical bond where a pair of electrons is are shared relatively equally between two atoms in the compound. Covalent bonds are formed between the fibers and reactive dyes. These are the strongest type of chemical bond,and are responsible for the excellent wash fastness of reactive dyes.

Crocking - Transfer of color from dyed or pigmented fabric by rubbing to a cloth name crocking cloth. Wet crocking refers to transfer of color from a piece of dyed fabric to another piece of fabric, or to an undyed area of the same fabric, while the fabric is wet. Dry crocking means the same, except that the fabric is dry.

Density - As a measure of physical properties of a substance, the ratio of the mass (weight) of the substance to its volume.

Depth of shade - Ratio of weight of dye to weight of goods dyed, usually expressed as percentage. Depth of shade (DOS), in these terms, is not really a very good way of comparing the darkness or intensity of color of finished fabrics, due to inherent differences in the hues of different dyes within a family, differences between dye families, and differences due to the nature of the fabric. Dye manufacturers’ shade cards are typically show one or two depths of shade for a particular dye, often between 1% and 4%, except for black, which is typically 3% to 6%.

Desizing - Desizing is an important step prior to dyeing fabric which is done to remove size materil from fabric, since size can interfere with dye uptake. Some size materials wash out easily. Starch is commonly used for size, and can be quite difficult to remove. Amylase enzymes are often used industrially for starch removal. Some sizes can be readily removed by hot water washing.

Dope Dyeing - Coloration of the polymer prior to manufacture of the fibre.This is really a misnomer, since the colorants are almost always pigments: “mass pigmentation” is a more accurate term. Some synthetic polymers such as polypropylene cannot be dyed after being made into fibres, and coloration by adding pigments to the melted material is the only method available. Pigmenting prior to making fibres can also produce washfastness and lightfastness that is higher than can be obtained with any dyeing process.

Dye Activator - One dye seller’s name for an alkali intended for use with reactive dyes; believed to be pure soda ash. This term is somewhat misleading: in the case of most reactive dyes on cellulose fibers, it is the fiber, not the dye, that is “activated” (an exception to this is vinyl sulfone dyes).

Electrolyte – This is a substance that makes an electrically conductive solution when it is dissolved in water. Electrolytes dissociate to form ions in solution. Fibers immersed in water develop a negative electrical charge at their surface. Most dyes are anionic, so the fiber tends to repel the dye. The presence of electrolytes in the dye bath helps to overcome this repulsion so that the dye can gain access to the surface of the fiber. The most common electrolyte in dyeing is sodium chloride (common salt). Sodium sulfate is used sometimes. The acids used with acid dyes also behave as electrolytes.

Exhaust Dyeing - Generally meaning the use of a dye bath of moderately large liquor to goods ratio, in which the fiber is immersed for some time, allowing the dye molecules to leave the bath and attach to the fibers. Exhaust dyeing is the typical process for most commercial fabric dyeing. It depends of dye substantivity.

Exhaustion – It is the leaving of a dye from the dye bath and attachment to the fibre being dyed. The ideal dye would exhaust totally - all the dye in the dye bath would end up on the fibre. Exhaustion is sometimes specified as a percentage. For example, 60% exhaustion would mean that 60% of the total amount of dye has attached to the fiber, and 40% is still in solution. Reactive dyes generally show moderate exhaustion while many acid dyes exhaust to the point that the dye liquor becomes nearly colorless.

Fixation – It is formation of the “final” bond between the dye and fiber. The bond type formed between the fiber and the dye varies with the type of dye and the fiber. As examples, reactive dyes fix by covalent bonding while acid dyes fix by a variety of mechanisms such as ionic bonding and hydrophobic forces. Disperse and vat dyes are fixed in the fiber largely by physical entrapment of insoluble dye within the fiber.

Fixative - In dyeing, a chemical that helps improve wash fastness of dyed fabric. Some types of dye do not bond strongly to fibers, and will wash out over time. Fixatives applied after dyeing can help, although some will degrade light fastness or cause shade changes.

Formosul – It is a trade name for sodium formaldehyde sulfoxylate.

Fuchsia – This is a bluish-red color named after a flower named after Herr Fuchs.

Glass Transition Temperature - The temperature above which a material changes from a brittle,“glassy” nature to a rubbery nature; on cooling, the material changes back to glassy Synthetic fibres, such as polyester and nylon show this change of physical character. The rate of dye uptake increases dramatically when the fiber is near or above the glass transition temperature. If the glass transition temperature is above the boiling point of water, as it is with polyester, the dyeing rate is extremely slow even at the boil.

Greige – It means the grey stage of fabric or the fabric used to dyeing. In North America, greige is often used to describe loom state fabric that is unbleached, contains size and lubricants, and may be a bit dirty. Greige goods are made ready for dyeing by singeing, desizing, scouring and usually bleaching.

Hand Feel -   the feel of a fabric through hand. Hand of a fabric is quite subjective, and often difficult to describe. Both chemical and mechanical treatments are frequently used to alter the hand of a fabric. To increase hand feel of fabric softener is used usually.

Hardness - With respect to water, a measure of the content of minerals that impart certain properties.
Calcium and magnesium ions are main cause of hardness in  water. They can interfere with some chemical processes in preparation and dyeing.

Hydrogen bond – It is the weakest chemical bond in which hydrogen that is already covalently bonded to one atom is electrically attracted to a lone pair of electrons on another atom. Some atoms such as oxygen are said to be very electronegative, which means that they strongly draw bonding electrons toward themselves. If hydrogen is bonded to such an atom, the hydrogen “appears” to have some positive charge.

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