Sunday, February 5, 2017

Denim Garment Finishing Treatments: Types and Process

Denim finishing:
In denim manufacturing, it is an amazing fact that one style of jeans is converted into different colors, which is achieved by garment washing. In today’s denim manufacturing, many denim finishing are done to give the jeans a broken-in look, much like what unwashed (dry denim) denim looks like after it has been worn many times. Denim finishing gives the fabric a softer feel, enhance its appeal without any strength loss and improve wear life, color retention and fashionable flair. There are two main types of denim finishing treatments one is chemical and another is mechanical processes which are done for achieving diverse distressed or abraded looks and any number of distinctive designs to fit consumer’s requests. Different types of denim finishing treatment giving fabrics the final touch to create the right high-quality fashion style.
Denim finishing treatment
Fig: Different types of denim finishing treatment
Chemical finishing of denim garments:
Various chemical finishes such as bleaching, enzyme washing and acid washing are the major types of chemical finishing used for denim.

Bleaching:
The bleaching is performed to discolor the denim in specific locations. The degree of bleaching action depends on the strength of the bleach, temperature and duration of the treatment.

Enzyme washing:
The environmental friendly finishing process ‘enzyme washing’ is used to create prominent effects at seams, pockets and hems.

The advantages of the enzyme process are:

  • Improved abrasion, colour removal without damaging the fabric strength
  • Simple and easy treatment
  • Environmentally friendly
  • Greater variety of effects are achievable
  • Shorter washing times.
Acid washing:
Acid washing is also a popular method for denim garment finishing. Acid washing is also known as stone washing, which is accomplished with pumice stones. Due to severe abrasive action, surface fiber damage occurs. In some instances the pumice is impregnated with potassium permanganate (an oxidative bleaching agent), this chemical being less damaging to the cotton fiber than sodium or calcium hypochlorite.

Following this bleaching and stone washing, the garments are washed with sodium bisulphite (reducing agent) to complete the removal of the brown color generated by the permanganate wash. This treatment has the effect of surface bleaching the indigo as well as giving the garments a softer handle and creating a distressed look.

Mechanical finishing of denim garments:
Mechanical denim finishing includes the process of stone washing and micro-sanding.

Stone washing:

Mechanical stone washing is similar to the chemical washing process of the acid wash. Here also stones are tumbled with freshly dyed denim, but it does not require any chemicals. The final look of the product depends on the size, shape and hardness of the stones used. In several instances the metal buttons and rivets get damaged due to the mechanical action.

Micro-sanding:

There are three types of micro-sanding: sandblasting, machine sanding and hand sanding. The sandblasting process is the most common, which is accomplished by passing a very abrasive substance through a nozzle at the denim at high speed and pressure that creates many different patterns in the denim. Machine sanding is performed by using a machine (similar to the machine used to sand down wood furniture), whereas hand sanding is done with a fine-grain sandpaper by hand.

The most recent development in the processing of denim has been the use of laser technology to imitate the human hand. VAV Technology GmbH produces the X-Burner system, a dry method of producing patterned effects on denim. This system allows a wide range of effects to be produced efficiently with minimum damage to the fabric. The VAV Technology for automated denim processing increases productivity, uniformity and quality of the finished product.