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COROTAN CRF

innovative auxiliary product for chrome retanning

The quality of raw hides and wet blues degrades gradually and inexorably year after year, and tannery technicians evermore often have to deal with wide-bellied and little firm leathers.

This problem is often treated with the use of “fillers” or of large amounts of retanning agents, which have negative effects on grain fineness and fastness and on dyeing quality.

Repico have perfected a simple and cheap chrome retanning system that produces very firm and full leathers with flat grain and very good dyeing properties.

The product is COROTAN CRF, an auxiliary to be added with or after Basic Chrome Sulphate used in retanning, in a suggested ratio of 0.75 parts of COROTAN CRF per 1 part of basic chrome sulphate 26/33.

The suggested quantity of chrome varies from 4% to 6%.

For example we can propose a retanning process with the ratios indicated below:
Basic chrome sulphate 26/33 6%
COROTAN CRF 4,5%
Run 2 hours, preferably overnight and automatic.

The morning after the section pH will be approximately 4.5/4.7, therefore it’s useless deacifiying because leathers are ready for the fatliquoring and dyeing phase.

Moreover there is exceptional exhaustion of basic chrome sulphate, as the residual float contains only few p.p.m.

COROTAN CRF is an innovative product that holds the economic aspect in great consideration, by accelerating the chemical process, as well as the impact on the environment, by enabling a high exhaustion of chrome used in retanning phase.

COROTAN CRF

Chemico-physical characteristics
Appearance: whitish powder
Composition: chrome complexed agents of organic and inorganic nature
Solubility: partial
pH 10%: 9 - 10
Light-fastness: good

Application

COROTAN CRF is an additive for chrome retanning to be used with or after the traditional basic chrome sulphate, with 25% chrome content and Sch 33% basicity.

COROTAN CRF gives excellent chrome float exhaustion and neutralises leathers evenly; the product constituents enable it to make bellies and empty parts of leather firmer.

Suggested ratio
4 – 6% Basic chrome sulphate 25/33
3 – 4,5% di COROTAN CRF