DIFFERENT TYPES OF DENIM GARMENTS WASHING-(Part 01)

Introduction:

The distressed jeans that we see around everywhere undergo a wide variety of wet as well as dry treatments to get the desired effects. Destroying denims is as much an art as it is a technique. The direction in Fashion is varied across all areas particularly in denim dry process, whether worn or torn to wrinkled or pressed; these trends can appeal to a wide range of consumers. These can be achieved by variety of denim dry processing techniques which are mainly dependent on physical and on chemical abrasion of the surface dye there by producing different wash-down looks to the denim fabrics. Hot spots are heavy/intense area on thigh or knee, which is made purposely to create used-look & on knee area if any whiskers lines are there, called knee star.

Different types of Dry process for Denim Wash:

Whiskering: 

whiskers are one of the most important design of a used look garment. The idea of whiskers is taken from the worn out lines and impression patterns generated by natural wearing on hips and front thigh area. On old jeans, a number of patterns can be finding consequential to fabric, body shape of user or sitting posture. It is also known as Cat's Whisker.

After Whiskering effect Of Denim Pants

Whiskering process

Whiskering Process: 
Various methods are designed to create this impression on jeans. Such as:- 

Mostly rubber balloons are available with different pattern designs. Garments are mounted on balloons and filled with air to get impressions of whiskers. Garment is scrubbed over pattern carefully with sand paper on engraved pattern lines. This operation requires high skilled labor and who can handle uniformity and sequence in whisker line. Fabric may damage during rubbing if care is not taken. This method is famous for high quality and cost effectiveness.

Sometimes separate patterns  are made and fixed on balloons to make mustaches. These patterns are made of thin rubber sheets and electric wires or rubber cords and pasted on balloons for pattern lines. Thin line patterns are very easy to work in that way but it is not much successful for broad lines.

Engraved patterns on thick board like hard rubber sheets are widely used for whiskers impression making. This idea is very simple to draw lines on rubber sheets and engrave them with blade. Garment is places on sheet and scrapped on specific area to draw this impression on garment. For its low cost patterns, it is most frequently used in small industries especially where the production is not consistent to style.

In some workshops it is done manually with the help of sharp edge rolled on fine wood sticks of pasted on plastic material. Before starting execution, placement and pattern must be marked on garment, this will help operator to execute the pattern right to match the aesthetics of garment.

Sand Blasting: 

Sand Blasting is the process of scrubbing off the garment by blowing high-speed air mixed with very fine particles of sand. This is a very successful and most widely used process for fashion articles. When the surface area of the garment is blasted, white cotton appears beneath the blasted area and the effect appearing is very similar to the worn out jeans. Sand blast provides a very uniform result, which cannot be achieved with its alternates. Its specialty is the merging effect that is blended with such a beauty that it has no difference with natural effect. 

High pressure of air produces a powerful backward thrust to operator so it is always recommended to fix the gun in appropriate stands rather than placing it on shoulders or using it with bare hands. On some fabrics sand blasting is not successful for it covers the characteristics of fabric. Especially in fabrics, which are famous for slob patterns it flattens the look. Specified areas for sand blasting are front thigh, back seat, back panel near bottom or front panel around knee. Some time full body blasting is also done for giving a unique look to fabric. Hot spots may be designed for more real look on front knees or back seat by intense blasting in these areas :

Sand Blasting

Procedure of Sand Blasting: 

• Individual garment to be processed is taken on a table.
• Air compressor is started and pressure to be maintained between 3 – 4 kg/sq.cm.
• Air compressor then stores air in the machine cylinder. Aluminum sand or silicon sand, Al2(SiO4)3, is then taken in the chamber of the blasting machine.
• Sand and compressed air are then sprayed over the garments at specific points at 10-200 angle by hand spray pipe. 
• Sands pass into the machine by regulating system.
• The machine comprises a blasting regulator and a hand regulator to control the amount of sand and compressed air respectively.
• The angle of sand blowing is very important. Higher the blowing angle, higher the fading effect and higher the risk of fabric damage.
• Fading is done on pre-marked areas.
• Sandblasting is a hazardous technique and therefore, the area should be isolated from other working areas.
• Handling of sandblasting gun is risky therefore, operators should use safety equipments like hand gloves, mask and gown. Production/hour/gun varies from 25 – 45 garments depending upon the degree of fading or extent of fading to be attained. 

Potassium permanganate spray (P.P Spray): 
Potassium permanganate spray is done on jeans to take a bright effect on sand blast area. One important thing about potassium permanganate spray is, this is usually a sporting process to increase the effect of sand blast. Potassium permanganate solution is sprayed on blasted area of jeans garment with the help of normal spray gun. This potassium permanganate spray appears pink on garment when fresh and turns to muddy brown on drying. The garment is hanged in open to dry after potassium permanganate spray and when the potassium permanganate turns its colors completely then it is considered to ready for next process. It is always followed by neutralization process. Sodium Meta bisulphate is most commonly used neutralizer. A number of products are available in market for neutralization process like sodium Meta bisulfate selected on the bases of effect required on blasted area. 

Potassium permanganate sprays concentrations ranges from .25 gm per liter to 15.00 grams per liter depending to required results and fabric types. Usually indigo died fabrics are treated with low concentrations whereas Black Sulfur Fabric requires high concentrations to treat with.

PP spray effect

Process of P.P Spray: 
1. Potassium permanganate spray in best is done in specific spray booths, where rubber dummies are installed for holding garments. Garments are mounted on the dummies and air is filled so the garment is full fit exposed. Specific dummies are used for different sizes and styles, like for kids, men’s, trousers, jackets, shirts etc. The booths are fitted with proper air exhaust system. This system leads the spray to treatment room where the chemical mixed air is usually passed through the water showers. Potassium permanganate is dissolved in water and the clean air is blown to open. Shower water is further treated with mild quantities of neutralizer before adding to main drain. But where the potassium permanganate spray is used in low concentrations then there is now need to treat shower water. This mild potassium permanganate mixed water is rather useful for water reservoirs to keep the water clean and germs free. 

2. Garments are mounted on air-filled rubber dummies and chemical is sprayed on blasted areas. The variables in spray process are as follows: 

• Distance of spray gun to garment: Less distance will give more defined and sharp effect whereas distant spray will result in more mild and merged effect. Distance ranges from one foot to two and a half feet. 

• Air to water ratio of gun: This is to be set very carefully. Low air pressure possibly will through KMnO4 drops on garment resulting in bright white spots whereas high pressure will produce very low bright effect spray effect to areas where it is not required. 

Potassium Permanganate Solution Concentration: This will control the extent of brightness.

To Be Continued.............