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Pure white? Pure business!

Pure white? Pure business!

New generation of tanning and retaning systems by CODYECO

Part 2 – Pure white? Pure business!

Part 1 took us thru luxury, long life of leather and regulations. Now you are going to learn how to prapare for upcoming changes.

Sustainability is a crucial factor for the survival of the entire leather industry.

No substances of health and environmental concern should be created during the entire leathermaking process.

The main aspects involved in this concept are:

  • To replace fossile based raw material with renewables
  • To reduce restricted substances as Aldehydes, Phenol, Salts in the effluent
  • To generate renewables sub products as Shavings and Trimmings
  • To produce biodegradable goods

CODYECO’s answer to the incoming environmental requirements are 3 innovative systems :

  • Pure White
  • Bio White
  • Dyeco Bio

In this article you will learn about first one which is a very good alternative to Aldehydes and to Synthetic Tanning technology –

PURE WHITE process

  • This technology lead to very white leathers with a very good mechanical and physical properties.
  • The leathers show an even and brilliant dyeing, good light and heat fastness and a versatile capacity of being used for many kind of articles.
  • The major characteristics of the PURE WHITE leathers are the roundness and the fullness.
  • In addition PURE WHITE process offers a combination of a high performance tanning process with the minimal environmental disturbances.

PURE WHITE involves readily biodegradable chemicals and doesnt bio-accumulate, so far the major environmental benefits of this system are:

– Minimal Effluent Concerns

– No chrome or formaldehyde or phenol content in the discharging floats

– Recyclable Shavings

– Unlike chrome shavings, PURE WHITE shavings are biodegradable and can be easily disposed of at landfill sites. Or better, the resulting wet white shavings, representing a freely available source of nitrogen, can be readily used as a supplementary nitrogen rich fertiliser for a variety of composting applications.

Ok, what is it exactly?

PURE WHITE process is a tanning system based on an organic tanning product FLORETAN THP

The active ingredient of the organic agent is :

THPS – Tetrakis Hydroxmethyl Phosphonium Sulphate



The tanning mechanism consists in the penetration into the pelt substrate of the unreactive form of FLORETAN THP. Once the penetration is complete, FLORETAN THP is converted into its active crosslinking form, by raising the pH of the system. The reactivity of the tanning agent depend on pH, concentration and temperature.

  1. Product penetrates in cationic quaternary form (THPS)
  2. Crosslinking occurs via collagen amino groups
  3. Conversion to tri-substituted active form on basification (THP)
  4. Tanning starts around pH = 3-3,2 and continues crosslinking up to pH = 5-5,5


  1. After a pickling at pH 3,2-3,3 FLORETAN THP is added to the tanning float in amount of

4-5 % on pelt weight.

  1. The penetration time, before to start with basification, is about 2 hrs, depending on the pelt thickness.
  2. The through cross-section could be monitored by a Selenium Indicator P (III)/(V) ratios. In order to crosslink the leather amino-groups, a slowly basification must be maintained up to pH 5,5-5,8.
  3. The residual not reacted THP must be deactivate by oxidative washing with Hydrogen

Peroxide or Borax.

  1. To scavenge in-processHCHO with appropriate washing-scavenger (Sodium metabisulphite) is recommended whether a very low HCHO leather is required (< 10 ppm).
  2. It is very important not to use Sodium Bisulphite and Meta-bisulphite during the tanning process because a strong and persistent bad smell arises from the drum.

Clear enough? If not CODYECO team is happy to help you, visit you tannery and show the real reaction in your drums! Contact CODYECO company under.

Sustainable Leatherians

New generation of tanning and retaning systems by CODYECO

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