Production method and Precautions of waterproof leather (PART 1)

ⅠThe choice of blue wet leather  

The blue wet leather which use to produce waterproof leather should meet a certain quality requirements, especially for the tight, stiff and thick waterproof leather products, the tightness of the blue wet leather itself must be guaranteed, must not be too soft.  If we produce soft waterproof products, we can use conventional blue wet leather relatively.  Additional, the water absorption of blue wet leather also is a very important index.  The blue wet leather which use to produce waterproof leather should meet the following requirements:  

1  Try to choose fresh blue wet skin, and should be keep clean after ash process.  If the storage time for blue wet leather is longer (more than 6 months), it needs to be retanned with chrome, the aim is to enhance the positive charge of blue wet leather, and make the charge evenly distributed in the whole cross section of blue leather, so as to improve the uniformity of leather;  

2  The tightness of blue wet leather is better, the side abdomen can not be too soft;  

3  Blue wet leather water absorption should not be too strong.  The hydroscopicity detection method for blue wet leather: put clear water droplets on the surface of dry blue wet leather, if it is like water droplets and stays for more than 2s, it is suitable for waterproof leather production;  Blue wet leather is not suitable for waterproof leather if water droplets spread and permeate the surface immediately.  

ⅡThe choice of chemical materials  

1. Retanning filling material  

In the production of waterproof leather, the selection of retanning filler material has a direct effect on the waterproof performance of waterproof leather. The retanning material, such as resin retanning agent, syntanning agent, tannin extract, filler, dye and various additives, all of these materials will affect the performance of waterproof leather.  Generally speaking, materials with strong hydrophilic properties, such as dispersants, levelling agents, anionic phenolic syntanning agents, resin materials with certain emulsifiers, tannin extracts with high degree of glycosylation and dyes with high content of neutral salts, have direct damage to the dynamic waterproofness of leather and should be avoided as far as possible, but conventional amino resin, acrylic resin retanning agent, styrene and maleic anhydride retanning agent, sulfone syntanning agent and tannin extract with low degree of glycation have little effect on waterproofing, while amphoteric tannin retanning agent contains more active groups and is easy to penetrate, absorb and fix, so it is an ideal material for producing waterproofing leather.  

The following retanning and filling  products from Ting Jiang are suitable for the production of waterproof leather:  

(1) Acrylic acid polymer: TJ-R5218, TJ-R5234, TJ-R5538, TJ-R5539, TJ-R5329, TJ-R5330, TWR5S, etc.;  

(2) Syntanning agent: TJ-R301, TJ-R425, TJ-R427, MXR, TJ-R7898, TJ-R7210, TJ-R353, TJ-R819, etc.;  

(3) Tannin extracts: TCR, TJ-R250m, TJ-R2708, etc.  

2  Waterproof materials  

Waterproofing products from Tingjiang company are recommended as follows:  

(1) General waterproof agent GWP: suitable for the production of all kinds of waterproof leather, especially for tight, stiff style waterproof products, such as outdoor or quartermaster,  which can achieve high waterproof effect by alone use.  The product has good weather resistance, high temperature resistance and yellowing resistance, especially in the static water absorption performance and it is the best product on the market.  Application performance is very outstanding, excellent permeability, and uniform distribution, which can give the leather plump and tight feel, even, bright dyeing, dry surface.  

(2) waterproof agent SWP: soft waterproof agent, suitable for clothing, gloves, sofa, car seat and other waterproof leather products.  The product is easy to emulsify, light resistant, yellowing resistant in high temperature, excellent permeability, and evenly distributed in the skin, we can get the fat-added leather plump, soft, delicate, smooth, bright color, bright leather.  

(3) waterproof agent TJ-A9981: suitable for soft leather waterproof products, with excellent waterproof performance, the leather treated by the soft, plump, the the oil run feeling of surface is very strong.  

(4) waterproofing agent TJ-A9986: should not use alone, should use together with waterproofing agent TJ-A999, TJ-A9981, then we can further improve the waterproof performance of leather, especially the static water absorption rate is improved significantly, at the same time, leather oil moisten sense is good, and color is bright.  

3  Additives  

Moisture rewetting protector BSP, efficient degreaser DOC, acid softening enzyme TJ-A489, ammonia free deashing agent TJ-A3604E, etc.