The Tanning Properties Of TBM Combine With Aluminum Salts And The Effect Of TBM Inhibit Cr⁶⁺ In Leather

The gallic acid was used as the raw material, after phenol hydroxyls wereprotected and cylation,3,4,5-trimethoxybenzoyl chloride was prepared, then itreacted with melamine, after unprotected, N,N’,N’’-(1,3,5-triazine-2,4,6-triyl)tris(3,4,5-trihydroxybenzamide)(TBM) was obtained. In order to study theperformance of TBM combination tannage with aluminum salts, and analysisedthe tanning property of TBM, we simulated the plant polyphenols tannage withaluminum salts. Then analysised and discussed about the properties of fourantioxidants eliminate and inhibit Cr(VI) in the sheep wet blue leather afterretanning by chrome, they were vitamin c (Vc), hydroquinone, gallic acid andTBM. Finally, we studied the performance of TBM, tert-butyl hydroquinone(TBHQ), gallic acid and butylated hydroxytoluene (BHT) as antioxidant in thelard and vegetable oil.Basing on vegetable tanning agents combined with aluminum tanning, weused the shrinkage temperature for the main value index, detecting the tanningperformance of TBM-aluminum tanning. The results showed that, the leathersshrinkage temperature can reach to67.3℃after tanned by TBM. It proved thatTBM has tanning property and the tanning mechanism is like the tannins that arerich in plant polyphenols. When the desage of TBM is8%and the aluminumsalts is10%(consider the mass of Al2O3), the shrinkage temperature of crust canreach to83.8℃. It can be concluded that TBM tannage with aluminum salts havesynergistic interaction.Lard and vegetable oil was used as a substrate, determinate the change ofacid value and peroxide value for the oils, to studied the antioxidation of TBM,gallic acid, TBHQ and BHT. The results showed that the four substances havedifferent levels of antioxidant activity in lard and vegetable oil, which can inhibitthe oils`acid value and peroxide value increased effectively. In the lard the strength of the oxidation resistance: TBM>TBHQ>gallic acid>BHT. In thevegetable oil the strength of the oxidation resistance: TBM>TBHQ≈gallicacid>BHT. The antioxidants could significantly reduced oils oxidation, late forthe induction period, and inhibit the oils`acid value and peroxide value increasedsignificantly.The sheep wet blue leather was treated by Vc, hydroquinone, gallic acid andTBM and found that if the leather did not treated by the antioxidants, the Cr(VI)in crust could be reach to34.8mg/kg. If the leather treated by the fourantioxidants treatment, Cr(VI) could decreased in different degree. It showed thatthese antioxidants can reduction Cr(VI) in crust to Cr(III), so the antioxidantscan eliminate Cr(VI) in the crust. The strength of reduction Cr(VI) ability:TBM>gallic acid> hydroquinone> Vc.In order to simulated the external environment (air, heat, light, etc.) impelCr(III) changed to Cr(VI) in leather in transportation and storage. We placed theleather in the oven at85℃for16hours after treated by the four antioxidants.Then determinated the content of Cr(VI) in the crust, found that by forceoxidation experimental conditions,the four antioxidants have the effect of inhibitthe Cr(III) into Cr(VI) and the inhibition increase by the content of antioxidantincreased. The TBM has the most effective inhibitory, the content of Cr(VI)always less than5mg/kg from the beginning of the experiment to the end. TBMcan effectively eliminate and inhibit the formation of Cr(VI) in leather.