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Improving The Quality Of Leather In Retanning And Dyeing (2)

2010/7/5 15:37:00 38

After the above process is completed, wash, squeeze water, vacuum drying, moisture regain and soften.

It is important to point out that neutralizing retanning agent Neu.triganP4 can neutralize leather easily and therefore is of great significance.

Similar neutralization and retanning agents have been produced by many foreign companies, but domestic leather companies have little input in this regard, and the market for neutralizing retanning agents is basically occupied by foreign companies.

Leather dyed for bright tones.

Dye dosage

It will not be very large, so it will soon be absorbed and fixed by leather, resulting in dyeing time which is not enough for leather that needs to be fully dyed.

Dyeing methods at high liquid ratio and high temperature were studied. 1% one 2% weak tannin cationic auxiliary tanning agents were used.

Chrome tanned leather

Pretreatment was carried out at neutralization to obtain good dyed leather.

However, the study of dyeing process is far less than that of dyeing auxiliaries.

The cationic auxiliary tanning agent combined with leather with cationic properties after chrome tanning improves the dyeing properties of leather.

The new dyeing auxiliaries form a firm complex with the dye, and then the dye binding speed decreases, the penetration rate increases, and the dyeing time is prolonged. Of course, the leather fatliquoring is promoted during this period.

The following two points should be noted in the application of such auxiliaries.

The use of auxiliaries with affinity for dyes is based on the formation of stable complexes with dyes in solution.

The stronger the effect, the higher the concentration of dye in the solution. Therefore, the addition of auxiliaries and dyes into the solution can achieve good dyeing results.

The new auxiliaries are not only combined with dyes, but also combine with all anionic products, which are combined with synthetic tanning agents.

In order not to reduce the activity of auxiliaries that bind to dyes, it is recommended that the chrome tanned leather be dyed by the following methods:

1. use auxiliaries

dyeing

Retanning before the end of dyeing;

2. it is economical to spray leather for dyeing leather, and high quality leather can be obtained.

The leather dyed by spraying should have good stability to the water, so that the dye will be firmly combined in the leather, so that the dye will not migrate under the action of water.

The light fastness of dyes can be solved by spraying 1:2 type metal complex dyes with high light resistance on leather.

This method can be used to obtain leather that is completely different from pigment coated and completely maintained aniline leather.

Melamine varnish can be applied to leather to keep the dye's light fastness.

In the development of new dyes and environmental friendliness, the development of dyes for domestic leather chemicals or chemical fibers is lagging behind.

After the EU imposed strict laws and restricted the use of azo dyes with carcinogenic effect, many dyed leather in China could no longer enter the European market.

The dyes in Korea, Taiwan and Europe immediately entered the mainland of China and squeezed the dye from the leather companies of the mainland to the market.

In addition, the domestic dye has advantages in terms of price, and there is a big gap between its performance and imported dyes. These two aspects are needed by domestic dyestuff companies.