Buffing, Dedusting and Insole leather in leather industry

 

Buffing  

Buffing has the following function:

1. Cleaning the flesh aspect from irregular fibres and residues of connective tissue thus on type uniform pressure conditions for mechanical finishing methodology (plate and  glaze finishing) and what is more to provide the leathers can attractive look for sale.
2. Giving suede and nubuck leathers the required even  nap  length (velveteen short nap longer 2 means nap).

For the production of suede leather buffing is first carried out with a coarse paper followed by a paper of finer grain. Apart from the size of grain the rotational speed of thee buffing cylinder also determines the fineness of nap. In order to roughen the fibres of worn garments made of suede or nubuck leather dry cleaners often treat the surface by means of sand blaster.

Dedusting 

The dust  occurring throughout buffing is removed by means that of exhaustors and picked up in chambers or wet dust systems. However, fine dust particles stay on the leather and cause impaired adhesion or  formation of dot throughout resulting finishing. Furthermore, suede and nubuck leathers will lose more color and cause staining because the dust is also dyed.  Therefore, a separate dedusting process is necessary. This is done by  means of a brush or air blast dusting machine. When using brush dedusting machines magnified frication produces an electrostatic charge which makes whole dedusting tougher.

Electrostatic charging is reduced if the dedusting rooms is more than 70%.The leathers to be dedusted and the processing rooms should therefore be conditioned by means off corresponding air humidifying plants.

Insole  leather

Insole leathers are manufactured by the tanning method used for  industry sole leathers. The only real distinction is that the leather is a smaller amount thick and also the texture is a smaller amount firm and dense. 

Rawstock: Shoulder and flanks of cattle hides of all weight classes  and larger calf and grasser (Temporary) skins.

Requirements of production 

Not like sole leather, insole leather has got to be capable of engrossing transpiration (sweating) of the foot and so bound amounts of moisture. Moreover  it must be  fast to perspiration and thus resistant  to  resulting shrinkage of area or embattlement ( loss of ductility  of  a material). Furthermore insole leather must  not have a high content of substance soluble in moisture. Intensive  laundry and smart fixation of the tanning agents are needed. Glutaraldehyde or condensation  products ought to be utilized in acceptable qualities  for  fastness to perspiration.

This group comprise the vegetably tanned sole leathers  and factory sole leathers. Sole  leathers are hard and less pliable,  factory sole leathers are more flexible. Chrome tanned  sole leather are of little importance today. 

Vegetable  tanned sole leathers:

1. Sole leather, tanned according to an old tanning method: Thick relatively hard firm and less pliable leather which has been produced by purely vegetable tanning. This is used for long soles half soles  and heels of heavy footwear. 

Rawstock: Heavy cattle hide of good substance with firm. dense fibre texture and greater  raw hides thickness.

3. sole leather tanned  according to modern tanning process: Requirements of production: 

However for rapid tanning methods more intensive deliming is necessary in order to accelerate penetration off the tanning agents.  Tanning is carried out with  higher percentage  tanning agents and extract such as quebracho  mimosa chestnut valonia or replacement syntans. Owing to  the use off higher concentration of  tannin a strict control of the tanning process  is absolutely necessary to avoid  case hardening.

4. Factory sole leather: These  factory sole leathers  are used  in shoe production as long and half soles for lightweight  footwear. 

Rawstock: Cow hides and lightweight cattle hides in weight categories of 15-30 kg as domestic and wild  hides, however  conjointly grasser veals and heavy calf skins. 

Requirements of production 

the method of  the processing and the tanning agents used are the same as for sole  leather production.  Besides an additional intensive deliming method moderate catalyst bating is performed. To achieve softness and suppleness  of the leathers soft  tanning vegetable and synthetic tanning agents  are used in appropriate qualities and with higher contents of fatliquoring  agents depending on the intended use.

5. Chrome sole leather: Manufacture of this product has greatly decreased due to the improvement  of synthetic sole materials over the past decades. These leathers are produced  by pure chrome tannage from heavy cattle and buffalo hides and very strong towel splits. These days they're only used for footwear that has no contact with wetness as they change their shape below the action of wetness and become terribly slippery. As opposition to vegetably tanned leathers they need an increased fastness to abrasion.

Requirements of production: So as to realize firmness and toughness of the sole it is high dried in the wet-stentered state. The stability of form in status are often improved by special water repellent treatment.