Production of sheep skin leather upper half of the key technology
In recent years, a style popular on the market ranging from garment leather and sheep leather between the shoe upper leather, we do call it "semi-upper leather", which is mainly used to do horse leather boots and bags, the thickness thinner skin, is also making Peacey clothing fabric upper. "Half-leather uppers," the general requirements are: thickness of 0. gmm-1. omm (single); flexibility as general leather clothing; compaction as the general soft leather uppers; grain flat thin, soft but not loose, feel good. In order to meet market needs, our joint research and production of sheep and a half shoe upper leather, the product received by customers.
Now some of the technical production process, the key points described in the post for the majority of tanning colleagues for reference.
First, the choice of raw hides and skins
Production of sheep and a half shoe upper leather, the soil should be of high quality sheep skin types or true quality northern skin, so that one can ensure there is sufficient finished leather tear strength and quality of grain, while in the process will not take to unnecessary trouble, such as heavy make up, bad in the other.
Second, the temperature section in enhancing fat
Strengthen in the wet degreasing operation to remove the grease inside the sheep skin, sheep and a half is to ensure the quality of shoe upper leather key.
As you know, the larger the fat content of sheep skin, usually in about 30%. If in the course of the sheep skin leather not the fat, then the quality of the finished leather will have serious repercussions. Such as storage of finished leather in return occurred during the frost, extinction, through the oil, smell and so on, with the de-
The fat is not a net addition, if the oil will affect not Tuojin the effect of tanning, leather dyeing uniformity and coating fastness, it is necessary to give full attention to the fat of sheep skin.
Fat sheep skin should be wet operatives throughout the segment. Generally gray bare skin after soaking, fleshing, painted base, push the hair, roll base and a series of operations, the oil in the skin surface (such as sebaceous glands or the surface of the free fat cells) which can be removed, but in the papillary layer and the network -like layer of oil is not easily Tuojin between, this must be a multi-stage process of degreasing operations, so that in dyeing, remove before refueling process. If the de-ash, ash removal, softening, pickling, tanning complex before, during and even when you can choose different degreaser for degreasing.
In the tanning process, when the oil is not Tuojin shortcomings in crust, the crust can also further softened, add fat to restore quality. However, after finishing and then a "frost", "oil spots" and other defects, it is quite difficult to deal with only a temporary solution.
Third, before the tanning process
Sheep in the semi-tanned leather upper pre-treatment to follow the general principles are: to protect grain, to prevent the loose surface, gentle handling, rather less hurried over.
Generally speaking, before the process of tanning essentials are:
1 quick immersion in order to reduce the production of bacteria and excessive loss of collagen.
(2) Before You control the water base coating, coated alkali hours high, low alkali.
3 roll-alkali effect should not be too strong.
4 ammonium salt off the ash.
5 moderate softening of the enzyme. Best use of imported enzymes, while softening the time should not be too long.
6 PH value of the end of pickling control 2.5 or so.
Fourth, cut tanning
Wet blue leather shaving that it is relatively simple, but it is not easy. In order to ensure the quality of finished leather, in order to avoid ironing when the whole leather finishing discontinuity, problems, it should be shaved when quality control, the entire skin thickness uniform, no parts of the poor, no jump knife defects.
V. retanning
The importance of re-tanning is well known. According to the actual production and product quality requirements, retanning generally conducted in two phases: the first stage of chrome-based tanning complex, can be added to some of the aliphatic tannins to increase grain leather flat fineness and fullness of the body degrees, then add chromium powder, supplemented with chromium tannins to enhance the grain of the leather of firmness and softness, adjust pH, standing overnight; in the second stage and after this time Add Acrylic Resin tanning agent, nitrogen-containing resin tanning agents, replacement of tannin, plants lack of agents, synthetic tanning agents, materials can be effectively absorbed, achieve better fullness and firmness.
Sixth, dyeing and processing fat
Sheep is black semi-leather uppers, full requirements of crust color, black is good, it normally takes two to three times a stain.
In order to achieve the desired softness of leather to choose high-quality semi-greasing agent of sheep leather upper for added fat and oil to meet, usually a variety of mixed fatliquor total amount should be controlled in 12% to 15% should be.
Seven, finishing
In order to achieve a pleasant look and feel good, finishing under a certain effort should be on, finishing the general process:
Resurgence Yishuai spray buffing or dry soft and cut a stretch board a trimming back of a roll ironing a cation of a spray one spray embossed upper middle one a spray varnish Yishuai finished a hand spray a light dose of a pressure product.
Described above in the process of production of sheep leather upper in a semi-technical key, the text does not cite the specific application of leather chemicals, we can choose their own situation. China's accession to the WTO, most of the material imported leather tannery prices can be accepted, so the import leather chemicals, especially re-tanning agents, greasing agent, additives have been widely used in tanneries, of course, made of the material is also fine, as greasing agent, film-forming resin, and thus the choice of materials is not difficult, the key is the application and compatibility. With high-quality raw materials and auxiliary materials, the level of attention control in production, will be able to produce high-quality leather upper half of the sheep.| Updated:2011.11.01 Source: Clicks:1773
