What is Coated Denim

Coated Denim: Why Some Jeans Look Like Waxed Cotton or Leather

One reader recently asked about coated denim. This is a very interesting surface treatment used in denim garments, especially jeans, to give them a different handle, appearance, and fashion value.

Coated denim refers to denim fabric or denim garments that have been given a special surface coating. This coating may make the denim feel as if the cotton has been waxed. In black denim, the effect can be even more striking: the jeans may shine almost like leather pants.

This is why coated denim is often used in fashion jeans, biker-style jeans, premium denim collections, partywear denim, and garments where a sharper, more polished look is required.

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What Is Coated Denim?

Denim is normally known for its rugged cotton character, twill weave, indigo fading, and casual appearance. In coated denim, a thin layer of coating material is applied on the surface of the fabric or garment.

This coating changes the surface behaviour of the denim. It may improve lustre, create a waxy touch, give a leather-like effect, reduce fading, or provide some resistance to stains and dirt.

Simple Explanation:
Coated denim is ordinary denim whose surface has been treated with a thin film-like layer. This layer may be pigment-based, acrylic-based, polyurethane-based, or resin-based, depending on the effect required.

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Common Types of Coating Used on Denim

The coating on denim is generally done using materials such as:

• Pigment coating
• Acrylic coating
• Polyurethane, or PU, coating
• Resin coating

1. Pigment Coating

Pigment coating gives denim a new surface appearance. It can create colour effects, dusty effects, worn effects, and fashion finishes. One interesting feature of pigment-coated denim is that it may change its look after washing and wearing.

With every wash, the coating may abrade slightly, producing a new appearance. This gives the garment a lived-in, evolving, and vintage character.

2. Acrylic and Polyurethane Coating

Acrylic coating and polyurethane coating are often used as transparent or semi-transparent coatings. These coatings form a thin protective layer on the denim surface.

Unlike pigment coating, acrylic and PU coatings may preserve the colour and fading properties of denim to some extent. They can also improve the lustre, surface feel, and handle of the garment.

Acrylic and PU coatings may provide:

• A smoother surface feel
• A mild glossy or leather-like appearance
• Protection against surface abrasion
• Some stain-resistant properties
• A breathable protective layer, depending on the formulation

3. Resin Coating

Resin coating is another method used to create special effects on denim garments. It is commonly used when a leather-like appearance or firm surface handle is required.

In one method, resin is applied with the help of a wooden handle and a rubber squeezer. The rubber squeezer helps to extract and spread the resin under pressure, allowing the coating to form a leather-like effect on the denim garment.

The resin material used for such coating may be a neutral cream-coloured paste, with a pH of around 7. It is miscible in cold water and may show resistance to heat up to around 200°C, depending on the product formulation. Some resin coatings are self-catalysed and resistant to chlorine.

Technical Note:
The exact behaviour of resin coating depends on the chemical formulation supplied by the manufacturer. Temperature resistance, chlorine resistance, handle, gloss, and wash durability may vary from product to product.

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How Is Coating Applied on Denim?

Coating can be applied either on denim fabric before garment making or directly on the finished garment. In fashion denim, garment coating is quite common because it allows special effects to be created on selected areas.

The coating may be applied by different methods, such as:

• Screen coating
• Brush application
• Knife-edge coating
• Rubber squeezer application
• Machine coating

Each method gives a slightly different surface effect. For example, brush application may create a more uneven handcrafted appearance, while knife-edge or machine coating can give a more uniform surface.

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Drying and Curing of Coated Denim

After the coating is applied, the denim fabric or garment must be dried and cured. Curing helps the coating film set properly on the surface of the fabric.

A commonly used curing condition is:

Curing Temperature: 150°C
Curing Time: 5 minutes

However, the exact drying and curing conditions should always be decided according to the chemical supplier’s recommendation, the type of denim, coating thickness, garment construction, and final performance requirement.

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Why Is Coated Denim Popular?

Coated denim is popular because it gives denim a more fashionable and premium appearance. It allows ordinary denim to be transformed into a garment with a glossy, waxed, or leather-like surface.

Some of the important benefits of coated denim are:

• It gives denim a new fashion look.
• It can create a waxed or leather-like appearance.
• It improves surface lustre.
• It can improve the feel and handle of the garment.
• It may provide stain resistance.
• It can protect the fading character of denim, depending on the coating used.
• It adds value to basic denim garments.

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Durability and Washing

Coatings on denim are normally designed to be reasonably permanent. A good coating should be able to sustain multiple launderings without completely disappearing from the surface.

However, coated denim should still be washed with care. Harsh washing, strong bleaching, high mechanical action, and aggressive tumble drying may reduce the coating effect over time.

Care Note:
Coated denim should preferably be washed inside out, with mild detergent, and without strong bleaching agents. This helps preserve the coating and surface shine for a longer time.

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Coated Denim vs Ordinary Denim

Feature	Ordinary Denim	Coated Denim
Surface	Natural cotton twill surface	Film-like coated surface
Appearance	Casual, rugged, indigo look	Glossy, waxed, polished, or leather-like look
Handle	Dry cotton feel	Smoother, firmer, or waxy feel
Fading	Fades naturally with wear and wash	Fading may be protected or modified by coating
Fashion Value	Classic denim look	Premium, fashion-oriented look

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Conclusion

Coated denim is a value-added denim finish that changes the surface character of jeans. It can make denim look waxed, glossy, polished, or even leather-like. Depending on the chemical used, the coating may be pigment-based, acrylic-based, polyurethane-based, or resin-based.

Pigment coating gives denim a changing and evolving fashion effect after washing. Acrylic and PU coatings form a transparent protective layer that can improve lustre, handle, breathability, and stain resistance. Resin coating can be used to create a stronger leather-like appearance.

In short, coated denim allows a basic cotton denim garment to move from casual wear into fashion wear. It is a good example of how surface finishing can add both aesthetic and commercial value to textiles.

What is the Meaning of T500 100% Cotton 100x100 185x295 118: 4PI (1/1)

I was recently asked this question by a reader.

Let me explain this to you:

T500: Means number of threads per square inch of the cloth are 500. This is also known as the thread count.
To calculate. Cut a square inch of the fabric. Count the number of weft threads in that region and count the number of warp threads in the region and add the two. Thread count = Number of warp threads+ Number of Weft threads.

100% cotton: Is Self Evident. The fabric is made of 100% cotton.

100x100: It is the English count of warp and weft.

185 x 195 : This indicate the number of ends ( warp threads) and number of Picks ( weft threads) per inch. Incidently 185+195= ~500 which is the thread count.

118" is the width of the fabric in inches.

4PI(1/1) : It means that the weave is one-up-one-down but four picks are inserted at a time. If two picks are inserted at a time it is called DPI ( Double pick Insertion) if single pick is inserted it is called SPI ( Single Pick Insertion).

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Ergonomics in Apparel Industry

Workers involved in sewing activities such as manufacturing garments, are at a risk of developing musculoskeletal disorders. Therefore it is imperative that the design of sewing station, stitching, finework,scissor work and material handling should be ergonomically appropriate. This site talks about ergonomical solutions for the same. A lot of sketches and diagrams are given for easier understanding. Some very quick rules of thumb can be derived from the sketches:

1. Chair Height is correct when the work surface is at elbow height and the sole of the foot should rest on the floor.

2. Schedule frequent and short breaks to stretch and change position.

3. Height and Tilt adjustable tables help employees access their work without using awkward postures.

4. Edges of work surfaces should be padded or rounded, so that the workers can rest their arms against them.

5. Use of Adjustable task lighting and magnifying glasses at workstation can take care of fine work inspection.

6. Shorter width table should be used for scissorwork so that the workers dont have to bend and reach so far.

7. Lifting of weight should be done at waist level.


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Distinguishing Linen from Cotton

The Following are the basic differences on the basis of which we can distinguish Linen from cotton:


1. Linen is about 20% more heavy than cotton.

2. It has a leathery feeling that is absent in cotton .

3. Cotton feels warmer(about 15-30% warmer) and holds heat better than linen.

4. On holding linen against light, the threads and the fibers composing the threads appear uneven and streaked as it is not possible to make linen yarn as uniform as cotton yarn.

5. On burning a linen thread, the fibers lie in the same position as before with no change except the scorched appearance. Burning a cotton thread causes the fibers to spread like a tuft.

6. Linen absorbs oil much better than cotton. To distinguish Linen with cotton in a piece of fabric, first remove all the impurities by washing and boiling. Then when if the fabric is dipped in oil, the linen fibers look transparent if held against the light. The Cotton remains nearly opaque.

7. Linen stands the action of sulphuric acid better than the cotton. To check a blend, first remove all the impurities then dip in con. sulphuric acid for a minute or two. Wash in water and dry on a blotting paper. All that remains on the blotting paper is linen. The cotton almost immediately dissolves in acid.




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Is Indigo Natural or Synthetic !! How was it manufactured earlier

The answer to the first part of question is "Both".

Indigo belongs to the category of water insoluble dyes.

It was first mentioned in a book in 13 BC by the name of Indian Blue. It is said that it has been used for dyeing in India and China 2000 BC. 

Originally it was made from Indigo plant.  The plant came to Europe in the 16th century via India. The leaves and stalk were kept in a vat filled with water and human urine. During this process, hydrogen was created by micro-organisms and acted as a reducing agent. It transformed the dyestuff in a water insoluble form. 

This fermented mass was stirred with poles. The reason for doing this was to transform the indigo into its water insoluble form again by oxidation. These water insoluble particles could then deposit on the bottom of the stationery vat. 

Then the liquid standing above was drained and a thin mash was left which was dried in open air and was put on the market in pressed or powder form.

Thus indigo started as a natural dye. However later it got manufactured using synthetic means.  In 1880  Adolf von Bayer succeeded in carrying out the first synthetic production of Indigo. In 1897, BASF was able to carry out the industrial scale production of Indigo. Now synthetic dyestuff has replaced the natural one almost completely. 

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Health Hazards in Textile Industry- Skin

Textiles have function of a 'second skin', substituting for the biological properties that other animals have evolved to cope with specific environments on this planet. Thanks to textiles, humans have even been able to enter the most extreme and inhospitable environments, such as interplanetary space.

At the same time, however, dermatologists and consumers have become increasingly aware of the risks garments may cause to human health. 

Contact dermatitis is the name given to localised rash or irrittion of the skin caused by the contact with a foreign substance.

When an allergen is involved there is an immune system reaction. The rash can show up a day or two after contact with the allergen. It will usually disappear in a few weeks, even if it is not treated.This is called Allergic Contact Dermatitis ( ACD)

When an irritant is the cause, the rash usually appears right away, possibly damaging the skin. The longer the skin is exposed to the offending substance, the more it will be damaged. The hands are often affected by this type of rash when harsh chemicals and substances are handled. This is Called ICD ( Irritant Contact Dermatitis).

Irritant dermatitis is one concern, but allergic contact dermatitis especially to certain colors used in textiles and to textile finishers even more so. The treatment of textiles or their raw materials with insecticides has alarmed authorities and prompted the industry to set safety standards known as 'eco seals'.

Textile is rated at number 5 of the top ten skin-unfriendly occupations.

At each stage their are irritants or allergens that are a potential cause of dermatitis.

Fibers commonly cause ICD and rerely ACD. The synthetic and wool fibers tend to be the irritants.The process of making yarns and preparation exposes to the irritants such as spinning oil, heat and polyvinyl alcohol.

During weaving the same irritants as in case of spinning apply.

Preparation process also exposes the workers to irritants.

It is dyeing, however, which is the principal cause of Occupational Skin Disease in the industry.The two groups of dyes i.e. reactive and disperse are the most frequest sensitisers.Chemicals and metals used are modants to give color their permanence can be irritants or allergens. 

A complete list of Irritants and Allergens in the textile industry is given here.

To conclude, As This site says - "The interaction between textiles and the skin is a close and reciprocal one. Therefore, a mutual exchange must be established between those who create textiles and those who treat skin. Thus a textile engineer must understand basic skin anatomy and microbiology. Similary a demermatologist must need to know about the structure of fibers, fabrics, dyes and finishes."

Sources:

http://allergies.suite101.com/article.cfm/basic_information_about_contact_dermatitis

http://allergies.suite101.com/article.cfm/basic_information_about_contact_dermatitis#ixzz0fRL97UBz

http://www.dermadoctor.com/pages/newsletter247.asp?WID={AECE738F-FA46-4

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How to Stonewash Better

How to Stonewash Better

Traditionally Natural pumice stone is used in denim washing process. It has the following disadvantages:

1. Residual pumice is difficult to remove from washed fabric/garment.

2. There is always a danger of damage to the equipment by overload of tumbling stones and material.This can also clog the drains and sewer lines.

Thus enzymes like cellulase are used to achieve the desirable appearance and soft handle for the fabric.

The problem with using enzymatic treatment is that the removed indigo dye can be redposited on the white yarn of the denim fabric. this process is called back staining and it can mar the look of garment.

Industrially cellulase is used along with Pumice stone for stone washing.

The cellulase can be at ph=7, when it is called the neutrual cellulase or at a pH of 5.5, when it is called the acidic cellulase.

In general the cellulase added is for 60min at 55 deg C as a percentage of the weight of the garment. It can be 3%, 6%, 9% or 12% depending upon the appearance required.

Pumice stone is generally taken as equal in weight that of the garment.

According to a study , the best stone washing ( as measured by the lightness of the sample is achieved for treatment with Neutral cellulases with pumice stone, acid cellulases with pumice stone, neutral cellulases, acid cellulases and pumice stone, in that order.

In the same order tensile strength of the sample decreases.

However, degree of back staining increases in the order of treatment with pumice stone, acid cellulases, neutral cellulases, acid cellulases with pumice stone and neutral cellulases with pumice.

which means a balance needs to be achieved- and where the effort to increase one desirable leads to increase in another undesirable one.


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How to think in colors or Color Theory for Designers

Colors are an inseparable part for any Textile enthusiast. It is therefore, important, to understand the colors as a physical and psychological phenomena. Equally important is to understand the effect of various color patterns on an overall experience.

This site presents a  three-part series on color theory. Here the meanings behind the different color families are discussed , and some examples of how these colors are used (with a bit of analysis for each) are given.

In Part 2 there is a  talk about how hue, chroma, value, saturation, tones, tints and shades affect the way we perceive colors.

Third part discusses color pattern for designers.

The treatment of the subject is done keeping a web-designer into mind. The implications are true equally for any textile situation.

This brilliant text is written by Cameron Chapman, who is a professional Web and graphic designer with over 6 years of experience.

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Chemical Identification of Silk

Please see the following link for details on chemical identification of silk.

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