| 摘要 |
Colouring of vegetable tanned leather uppers is carred out during the tanning process, with acid, metal-complex or direct dyes. Skins are treated with a 6% of a synthetic tanning prepn. based on a phenol sulphonic-acid phenol, urea, and formaldehyde condensate, with agitation for 1-3 hrs. followed by a 5% vegetable tanning extract of Quebracho and mimosa, 1% mineral oil and 3-4 hrs. agitation and by 3-5% vegetable tanning extract of oak, modified chemically by naphthalene-carboxylic acids and sulphitising. This is followed by 0.5-4% phenol-sulphonic-acid-phenol, -urea and formaldehyde based synthetic curing agent with agitation for 1-3 hrs. The treatment is continued with 1-4% of mimosa extract, 0.5-4% acid-, metallic complex- or direct-dye, dissolved in boiling water, cooled back to 40 deg.C and agitated for 12-19 hrs.
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