KR20230033597A - Manufacturing method of lizard leather by optimization of de-scaling, de-calcium and bleaching process - Google Patents

Abstract

The present invention relates to a method for manufacturing excellent leather by processing natural leather of a lizard. The present invention can provide high quality lizard leather having excellent mechanical properties while having high flexibility, through the optimization of descaling, di-calcium, and bleaching processes.

Description

Manufacturing method of lizard leather by optimization of de-scaling, de-calcium and bleaching process}

The present invention relates to a method for producing superior leather fabric through descaling, di-calcium, and bleaching process optimization of natural leather of lizard, and a descaling agent used in the production thereof.

Lizard leather is a very popular material among reptile fabrics, and Southeast Asia, Africa, and South America are the main producers, and Java Island's lizard skin is famous.

As for the surface characteristics, there are rice patterns and delicate patterns of spots along the grain, and crocodile-like patterns are on the sides and tail. Ring-patterned lizard leather is the best leather, and in the case of this product, a round pattern is printed on the back. It is small in size and is mainly used for decorative trimming of gloves, belts, handbags, shoes, etc. Most of them have subsidiaries in Indonesia and Malaysia. , and some painted lizard leather is imported and sold.

In order to supply leather products of luxury brands as leather fabrics, it is necessary to satisfy physical properties such as high mechanical properties and flexibility, but there is no technology for processing lizard leather in Korea.

Korean Patent Publication No. 10-2004-0027473 (published on 2004.04.01.) Korean Patent Publication No. 10-2010-0027852 (published on 2010.03.11.)

The present inventors developed a descaling process that can maximize the luxury of lizard leather fabric by minimizing damage to the skin layer, and also developed an optimal pH and calcium component removal process that can secure the shape stability of leather fabric during softening treatment. In addition, we developed bleaching treatment conditions and methods that can prevent the deterioration of leather properties by performing the existing three-step bleaching treatment process as a one-step process, and high-quality lizard natural leather fabric manufactured using these processes want to provide

The lizard natural leather fabric manufacturing method of the present invention for solving the above problems includes: 1 step of preparing lizard leather subjected to hydrophobic treatment; A second step of producing a leather from which a skin layer is removed by performing a de-scaling treatment on the soaked lizard leather; A third step of softening the leather from which the skin layer has been removed; and a fourth step of bleaching the softened leather.

Another object of the present invention relates to a descaling agent used in the descaling treatment in the above manufacturing method, and includes a degreasing agent, sodium hydrosulfide, sodium sulfide and water.

The lizard leather fabric manufactured by the descaling agent of the present invention and the method proposed by the present invention has excellent mechanical strength such as friction fastness, tensile strength, tear strength, and burst strength while minimizing damage to the skin, as well as excellent flexibility. , It has an appropriate oil content, etc., so it is possible to provide a high-quality lizard natural leather fabric applied to expensive leather products.

1 is an image for explaining the inner shape of lizard hides and hides.
2 is an experimental image comparing the amount of scale according to the amount of sodium sulfide used as a descaling agent in Example 1.
3a to 3e are SEM measurement images of leather descaling with descaling agents having different amounts of sodium sulfide.
4 is an experimental image comparing the amount of scale according to the amount of sodium hydrosulfide used as a descaling agent in Example 1.
5a to 5d are SEM measurement images of leathers descaling with descaling agents having different amounts of sodium hydrosulfide.
6 is a photograph of the surface of lizard nappy subjected to descaling by varying the drum rotation speed.
7 is a photograph of lizard napi prepared by descaling at a drum rotation speed of 5 RPM and a photograph of scale removed from leather.
8 is a photograph of lizard napi subjected to softening treatment in Example 2.
9 is a measurement result of pH change over time during the softening treatment according to the composition of the softening agent in Example 2.
10 is a photograph of lizard napi bleached using 10 parts by weight of Na ₂ S ₂ O ₂ in Example 3.

The term “raw skin” used in the present invention refers to lizard leather in which a skin layer, which is a scale layer, exists because a descaling process is not performed, and “nappy” means a skin layer, which is a scale layer, is removed by performing a descaling process. It means lizard leather.

Hereinafter, a method for manufacturing (or processing) the lizard natural leather fabric of the present invention will be described in more detail.

In order to provide a high-quality leather fabric, the present invention obtains lizard leather from Heng Long, which is supplied to Louis Vuitton, for heat shrinkage temperature, friction fastness, tensile strength, tear strength, Ca content, Cr content, and oil content. , flexibility and other physical properties were measured, and their physical properties are shown in Table 1 below.

heat shrinkage temperature
(℃) Friction fastness (grade) tensile strength
(kgf/mm ² ) tear strength
(kgf/mm) case wet 92 4 3-4 2.6 1.2 Cr content (ppm) Ca content (ppm) Oil content (%) Flexibility (mm) Burst strength (kgf/cm ² ) 25,600 109 1.6 2.2 18.5

The present invention for manufacturing lizard natural leather having excellent physical properties that meets or exceeds the heat shrinkage temperature, friction fastness, tensile strength, tear strength, Ca content, Cr content, oil content, flexibility and burst strength of Table 1 above. The manufacturing method of lizard natural leather fabric is as follows.

The method for manufacturing a lizard natural leather fabric of the present invention includes the steps of preparing a lizard hide treated with water droplets; A second step of preparing a napkin from which a skin layer is removed by performing a de-scaling treatment on the soaked lizard hide; A third step of softening the napi from which the skin layer has been removed; and a fourth step of bleaching the softened napi.

In addition, after step 4, a tanning treatment process and a retanning process may be further performed.

In addition, a dyeing process, an eggplant process, and/or a painting process may be further included.

As shown in FIG. 1, the lizard leather in the first step has a skin layer of a scale layer formed on the surface of the epidermis layer unlike conventional cowhide, and de-scaling to remove it is absolutely necessary. In addition, the epidermis must be prevented from being damaged during the descaling process. As shown in FIG. 1, in the case of scales on the surface, the content varies depending on the size and lizard type, but the organic component is composed of collagen, and the inorganic component is composed of carbonate, phosphate, and some calcium components. A descaling process is necessary because a bleaching problem in the bleaching process and disproportionate salt may occur during dyeing when scale remains on the inner skin of the jade. Therefore, the scale covering the epidermis of the lizard must be removed without damaging the epidermal layer.

To this end, in the present invention, the second step is a step 2-1 of performing a descaling process after putting the soaked lizard hide and a descaling agent into a drum; and step 2-2 of immersing the lizard leather obtained in step 2-1 in an aqueous solution of potassium hydroxide for 50 to 80 hours, followed by washing and dehydration to obtain leather from which the skin layer has been removed. process can be performed.

The descaling agent in step 2-1 may include a degreasing agent, sodium hydrosulfide, sodium sulfide, and water. Preferably, the descaling agent is Compared to parts by weight, it may include 0.1 to 1.0 parts by weight of a degreasing agent, 3.0 to 6.0 parts by weight of sodium hydrosulfide, 6.0 to 12.0 parts by weight of sodium sulfide, and 3,500 to 4,500 parts by weight of water, more preferably the descaling agent. Based on 100 parts by weight of lizard hide, 0.3 to 0.7 parts by weight of a degreasing agent, 3.5 to 5.0 parts by weight of sodium hydrosulfide, 7.0 to 10.5 parts by weight of sodium sulfide, and 3,800 to 4,200 parts by weight of water may be included. At this time, when the sodium hydrosulfide content is less than 4.0 parts by weight or the sodium sulfide content is less than 7.0 parts by weight with respect to 100 parts by weight of the lizard raw skin, there may be a problem that scale remains on the surface of the descaled lizard nappy, When the sodium sulfide content exceeds 6.0 parts by weight or the sodium sulfide content exceeds 12.0 parts by weight, there may be a problem in that the skin layer of the napkin is damaged, so it is good to use it within the above range.

In addition, the descaling process in step 2-1 may be performed for 50 to 80 minutes at a drum rotation speed of 3 to 8 RPM and 25 to 35 ° C, preferably at a drum rotation speed of 4 to 7 RPM and 25 to 35 ° C. It may be performed for 50 to 70 minutes, more preferably for 50 to 70 minutes at a drum rotation speed of 4 to 6 RPM and 27 to 33 ° C.

And, when performing the descaling process, the drum is rotated for 8 to 12 minutes and then immersed for the remaining 48 to 52 minutes to minimize damage to the skin. It is good to perform at about the above time ratio.

At this time, if the drum rotation speed is less than 4 RPM or the execution time is less than 50 minutes, the descaling effect may be insufficient or the process time may be too long, and the drum rotation speed exceeds 7 RPM or the process time is 80 minutes Since damage to the skin layer of lizard nappies may occur if it exceeds , it is preferable to perform at a drum rotation speed within the above range.

In addition, washing and dehydration in step 2-2 may be performed by a general method used in the art.

In addition, in the second step, steps 2-3 of performing a deliming process on the dehydrated napi may be further performed. At this time, the demineralization process may be performed by immersing the dehydrated napi in an aqueous solution of lime at a concentration of 5 to 10% by weight for 60 to 80 hours and then dehydrating.

Next, in the manufacturing method of the present invention, the third step is a softening process to increase the flexibility of leather by removing the calcium component contained in napkins. It should be carried out under pH.

Step 3-1 of the softening process in the third step is to perform a softening process after inputting the skin layer removed and the softening agent to the drum; and step 3-2 of washing and dehydrating the leather after step 3-1.

The softening agent in step 3-1 may include ammonium sulfate, ammonium chloride, lipafron, boric acid, and water, preferably in 100 parts by weight of lizard nappy. 2.0 to 3.0 parts by weight of ammonium sulfate, 2.0 to 3.0 parts by weight of ammonium chloride, 0.1 to 0.6 parts by weight of Lipafron, 0.40 to 1.20 parts by weight of boric acid, and 3500 to 4500 parts by weight of water, more preferably lizard Based on 100 parts by weight of Napi, 2.0 to 2.6 parts by weight of ammonium sulfate, 2.2 to 2.8 parts by weight of ammonium chloride, 0.1 to 0.5 parts by weight of Lipapron, 0.50 to 1.00 parts by weight of boric acid, and 3800 to 4200 parts by weight of water may be included. At this time, with respect to 100 parts by weight of lizard napi, when the content of ammonium sulfate and/or ammonium chloride is less than 2.0 parts by weight, the effect of removing calcium in the napkin may be insufficient, and when the content of ammonium sulfate and/or ammonium chloride exceeds 3.0 parts by weight, Although the removal of calcium is good in nappies, there may be a problem that the physical properties of the leather deteriorate because the pH is too high. In addition, when the boric acid content is less than 0.40 parts by weight, the pH of the leather subjected to the softening process may be high, resulting in a decrease in leather properties, and when the boric acid content exceeds 1.20 parts by weight, acid swelling occurs, and the pH is It may be too low and there may be a problem of poor shape stability.

In addition, the softening process in step 3-1 may be performed for 100 to 150 minutes at a drum rotation speed of 3 to 8 RPM and 20 to 30 ° C., preferably at a drum rotation speed of 4 to 8 RPM and 20 to 30 ° C. Performing for ~ 140 minutes is good in terms of morphological stability of napkins and calcium removal efficiency in napkins.

During the softening process of step 3-1, the pH change is preferably performed in the range of 6.4 to 8.3, preferably pH 6.5 to 8.2.

And, washing and dehydration in step 3-2 can be performed by a general method used in the art.

The calcium (Ca) content in the dehydrated leather in step 3-2 is 2,600 to 2,800 mg/Kg, preferably 2,630 to 2,780 mg/Kg, and the pH of the dehydrated leather may be 8.1 to 8.3.

Next, in the manufacturing method of the present invention, the fourth step is a bleaching treatment process, and the bleaching treatment process performed as a conventional tertiary process can be performed as a one-step bleaching process.

In the single-step bleaching treatment method, step 4-1 of adding softened leather and water to a drum and then adding sodium chloride (NaCl) to the treatment for 15 to 30 minutes; Step 4-2 of adding potassium permanganate to the drum and treating it for 100 to 140 minutes; Step 4-3 of adding Na ₂ S ₂ O ₂ to the drum and treating it for 100 to 140 minutes; and steps 4-4 of washing and dehydrating the bleached leather, and steps 4-1 to 4-3 are continuously performed in one reactor.

Step 4-1 is performed by adding 800 to 1200 parts by weight of water, preferably 900 to 1000 parts by weight, based on 100 parts by weight of skins in the drum, and 25 to 30 parts by weight of sodium chloride, preferably 27 to 30 parts by weight It is good to put a weight part. At this time, if the sodium chloride input is less than 25 parts by weight, acid swelling may partially occur, and if used in excess of 30 parts by weight, it may cause uneconomical and environmental problems.

Step 4-2 is performed by adding 3.0 to 6.0 parts by weight of potassium permanganate, preferably 3.5 to 5.5 parts by weight, based on 100 parts by weight of skins in the drum. At this time, if the potassium permanganate is less than 3.0% by weight, the bleaching effect is If it exceeds 6.0% by weight, the bleaching effect is excellent, but the surface of the leather fabric may be damaged.

In step 4-3, 8.0 to 17.0 parts by weight of Na ₂ S ₂ O ₂ , preferably 8.5 to 16.0 parts by weight of Na ₂ S ₂ O ₂ are added to 100 parts by weight of napi in the drum. At this time, Na ₂ If the S ₂ O ₂ content is less than 8.0 parts by weight, the bleaching effect may be insufficient, and if it exceeds 17.0 parts by weight, the color difference may be too low and damage to the surface of the leather fabric may occur.

Lizard nappies prepared by performing steps 2 to 4 in the above-described method may further perform a tanning treatment process and a retanning process to increase the tanning effect. An example of process conditions when performing the tanning process and the retanning process is shown in Table 2 below.

process Content (parts by weight) ingredient time (minutes) note tanning process
and tanning agent
(Tanning) 300 water 30℃
pH3.6~3.8 2.0 to 4.0 Cr-powder 60 2.0 to 4.0 Synthetic fatliquor 30 2.0 to 4.0 Cr-powder 60 0.1 to 1.0 NaHC0 ₃ 30 0.1 to 1.0 MgO Overnight Heat shrinkage temperature measurement, Drain&Rinse, chromium oxide (Cr ₂ O ₃ ) content measurement retanning process
and retanning agents
(Retanning) 100 water 40℃
pH4.5~5.5 2.0 to 4.5 Natural tanning agents (Mimosa, Quebracho, Tara) 30 1.5 to 3.0 Neutral syntan 20 0.5 to 1.5 Sodium formate (NaHCO ₂ ) 10 0.5 to 1.5 Sodium bicarbonate (NaHCO ₃ ) 20 0.1 to 0.5 Sodium Carbonate (Na₂CO ₃ ) 1/2x30 Dewatering and rinsing In Table 2, the contents are parts by weight of the composition relative to 100 parts by weight of lizard napi.

The lizard natural leather fabric manufactured by the lizard natural leather fabric manufacturing method of the present invention described above has a heat shrinkage temperature of 91 to 94 ° C, flexibility of 1.6 to 2.8 mm, tensile strength of 2.4 to 2.7 kgf/mm ² , and tear strength of 1.6 to 2.5. kgf/mm, friction fastness of dryness grade 4 or higher, friction fastness of wet grade 4 or higher, bursting strength of 14.0 to 18.0 Kgf/cm ² , oil content of 1.4 to 2.0% by weight, preferably heat shrinkage temperature of 91 to 94℃, Flexibility 2.2 ~ 2.7 mm, Tensile strength 2.4 ~ 2.7 kgf/mm ² , Tear strength 2.0 ~ 2.4 kgf/mm, Friction fastness 4th grade or higher, Friction fastness 4th grade or higher, Burst strength 14.0 ~ 17.0 Kgf/cm ² , oil and fat content of 1.6 to 1.8% by weight may be satisfied.

Hereinafter, the present invention will be described in more detail based on examples. However, the scope of the present invention should not be construed as being limited by the following examples.

[Example]

Example 1: Deriving the optimal composition of the descaling agent

As raw material skin, A lizard raw skin treated with water for 3 days was prepared. The weight of the dried leather was 150 (±20) g.

(1) Deriving the optimal content of sodium sulfide in the descaling agent

With respect to 100 parts by weight of lizard raw skin, each descaling agent having the composition shown in Table 3 was prepared, and after adding the lizard raw skin and descaling agent, which were subjected to hydrophobic treatment using the same, at a drum rotation speed of 5 RPM under 25 ° C. After rotating the drum for 10 minutes, the descaling treatment was performed by immersion for 50 minutes.

In addition, the drainage was filtered to compare the amount of scale stacked on the filter paper, and the results are shown in Table 3 and FIG. 2 below. In addition, the surface of the descaling-treated leather was measured (50 times) using a scanning electronic microscope (SEM), and the results are shown in FIGS. 3A to 3E.

division degreaser sodium hydrosulfide sodium sulfide water Weight after filtering etc One 0.5
parts by weight 4.0 parts by weight 0 4000
parts by weight 0.07g - 2 4 parts by weight 0.22g - 3 8 parts by weight 0.31g - 4 16 parts by weight 0.58g sulfur gas generation 5 24 parts by weight 0.63g sulfur gas generation

Referring to Table 3 and FIG. 2, it was confirmed that as the sodium sulfide content increased, the scale of the lizard skin layer was removed, and the descaled drainage solution became cloudy as the sodium sulfide content increased, and the scale precipitate increased. In addition, when the drainage was filtered, it was confirmed that the suspended matter increased according to the change in the content, and it was confirmed that there was a problem in that sulfur gas was generated when the sodium sulfide content was used in an amount of 15 parts by weight or more.

In addition, referring to FIG. 3, as a result of SEM imaging of the surface of the lizard leather, it was confirmed that scale remained on the surface when the sodium sulfide content was 0 or 4 parts by weight (FIGS. 3a and 3b). In addition, when 16 parts by weight or more was used, not only the skin layer but also the epidermis layer were damaged, making it difficult to confirm the shape of the unique pattern of lizard leather (FIGS. 3d and 3e).

Through this, it was confirmed that the optimal amount of sodium sulfide used was 6.0 to 12.0 parts by weight, preferably 7.0 to 10.5 parts by weight, and more preferably 7.5 to 10.0 parts by weight.

(2) Deriving the optimal content of sodium hydrosulfide in the descaling agent

With respect to 100 parts by weight of lizard hide, the sodium sulfide content was fixed at 8 parts by weight, and as shown in Table 4, descaling agents having different sodium hydrosulfide contents for 100 parts by weight of lizard hide were prepared, respectively. After adding the soaked lizard hide and descaling agent, the drum was rotated at a drum rotation speed of 5 RPM for 10 minutes at 25° C., and then immersed for 50 minutes to perform descaling treatment.

In addition, the drainage was filtered to compare the amount of scale stacked on the filter paper, and the results are shown in Table 4 and FIG. 4 below. In addition, the surface of the descaling-treated leather was measured (50 times) using an EM (Scanning Electronic Microscope), and the results are shown in FIGS. 5A to 5D.

division degreaser sodium sulfide sodium hydrosulfide water Weight after filtering etc One 0.5
parts by weight 8.0 parts by weight 0 4,000
parts by weight 0.28g - 2 4 parts by weight 0.31g - 3 8 parts by weight 0.42g sulfur gas generation 4 12 parts by weight 0.48g sulfur gas generation

Looking at the experimental results of Table 4 and FIG. 4, as the sodium hydrosulfide content increased, the scale of the skin layer of the lizard hide was removed, the descaling-treated drainage solution became turbid, and the content change when the drainage solution was filtered. It was confirmed that the floating matter increased and the precipitate of the scale increased according to. However, the degree of descaling was insufficient rather than the measurement result for each sodium sulfide content.

In addition, looking at the SEM measurement results of the lizard leather surface of FIGS. 5A to 5D, it was confirmed that some scale remained on the surface when the sodium hydrosulfide content was 0 parts by weight, and when 12 parts by weight or more was used, not only the skin layer but also the epidermis (Epidermis) layer was partially damaged. Considering that sulfur gas is severely generated from the sodium hydrosulfide content of 8% by weight or more, it was confirmed that the optimal sodium hydrosulfide content in the descaling agent was 3.0 to 6.0 parts by weight, preferably 3.5 to 5.0 parts by weight.

(3) Deriving the optimal drum rotation speed during descaling

In the case of lizard leather, since physical damage can cause damage to the skin layer when the scale covering the epidermis is removed, an experiment was conducted to find the optimum rotational speed condition of the drum to minimize physical damage.

An experiment was performed using the same soaked lizard hide as in (1) and (2), but using a decaling agent having the composition shown in Table 5 with respect to 100 parts by weight of lizard hide, the drum rotation speed was increased. Each experiment was performed differently. In addition, a picture of the surface of the descaling lizard napi is shown in FIG. 6.

In addition, a picture of lizard nappy prepared by descaling at a drum rotation speed of 5 RPM and a picture of scale removed from the leather are shown in FIG. 7 .

division degreaser sodium sulfide hydro
sodium sulfide water drum rotation
Speed (RPM) after filtering
weight descaling
degree One 0.5
parts by weight 8.0 parts by weight 4 parts by weight 4,000
parts by weight 5 0.31g Great 2 10 0.10g Great 3 20 0.21g Inadequate

As a result of the experiment according to the drum rotation speed during descaling, the larger the RPM of the drum, the better the descaling, but physical impact causes surface damage (decreased shape stability). It was confirmed that it is advantageous to perform de-scaling under ~ 8 RPM.

Example 2: Derivation of optimal composition of softener

Since the lizard leather is hard because the epidermis contains calcium for protection from the outside, the epidermis must be made flexible by removing the calcium component and the shape stability must be maintained by selecting the optimal pH.

Thus, an experiment was conducted to find the composition of the optimum softener.

(1) Derivation of optimal content of softener

Lizard nappies prepared by descaling in the same manner as in Section 1 of Example 1 (3) were prepared.

After adding the lizard napi to the drum, a softening agent having the composition shown in Table 6 was prepared with respect to 100 parts by weight of the lizard napi, and then put into the drum to perform a softening treatment at 25 ° C. for 120 minutes, A photograph thereof is shown in FIG. 8 .

The pH change was measured at a specific time point during the softening treatment process, and the results are shown in Table 6 and FIG. 9 (category 1 to 6). In addition, after performing the softening treatment process for 120 minutes, washing and dehydration processes were performed, and then the Ca content of the softened lizard napi was measured, and the results are shown in Table 6 below.

Softener composition
(Used parts by weight for 100 parts by weight of lizard nappy) pH change according to process time Ca content
(mg/kg) Lizard nappy before softening treatment 18,200 division Lipa
fron
(parts by weight) water
(parts by weight) Ammonium sulfide
(parts by weight) chloride
ammonium
(parts by weight) 5 minutes 10 minutes 30 minutes 60 minutes 90 minutes 120 minutes - One 0.2 4,000 0.5 0.5 9.4 9.8 9.8-
9.6 9.6 9.6 9.6 7,200 2 1.0 1.0 9.1 9.7 9.5 9.4 9.4 9.4 6,910 3 1.5 1.5 8.9 9.5 9.4 9.4 9.3-
9.4 9.3 6,280 4 2.5 2.5 8.6 9.1 8.9 8.8 8.8 8.8 5,830 5 4.0 4.0 8.3 8.8 8.6 8.4-
8.6 8.6 8.6 5,790 6 5.0 5.0 8.2 8.6 8.5 8.4 8.4 8.4 5,710

Looking at the experimental results of Table 6 and FIG. 9, as the content of ammonium sulfide and ammonium chloride increases, the pH decreases and the Ca content decreases, but the decrease tends to be insignificant from 5 parts by weight or more. However, unlike bovine skin, in case of lizard skin, since it constitutes a thin and hard epidermis, it was found that the Ca removal efficiency was generally low with only ammonium sulfide and ammonium chloride.

Therefore, the amount of ammonium sulfide and ammonium chloride used was fixed at 2.5 parts by weight, respectively, and an experiment was conducted to remove Ca and efficiently soften it by applying an acid such as an organic acid.

(2) Application of organic acid and deduction of optimal content of softener

pH and softening treatment by performing softening treatment under the same conditions using a softening agent additionally using boric acid or formic acid as shown in Table 7 in the softening agent having the same composition as Section 6 of Table 6 above The Ca content in one napkin was measured.

Classification (parts by weight used for 100 parts by weight of lizard nappy) pH change according to process time Ca content
(mg/kg) etc 10 minutes 30 minutes 60 minutes 90 minutes 120 minutes Using 2.5 parts by weight of ammonium sulfide + 2.5 parts by weight of ammonium chloride
Treated lizard nappy (softener of category 4 in Table 6) 5,830 boric acid content
(parts by weight) 0.1 7.4 7.8 8.0 8.4 8.4 3,100 0.3 7.2 7.6 8.0 8.2 8.2 2,950 0.5 6.9 7.8 8.0 8.1 8.1 2,740 1.0 6.6 7.4-7.6 7.8 7.8 7.8 2,670 low pH 1.5 6.4 7.4-7.6 7.7 7.7 7.7 2,630 low pH formic acid
(parts by weight) 0.1 6.8 7.4 8.0 8.2 8.2 2,920 0.3 6.5 7.2 7.6 7.8 7.8 2,830 low pH 0.5 6.2 6.4 7.4 7.5 7.5 2,720 low pH 1.0 5.8 6.2 7.0 7.2 7.3 2,610 acid swelling 1.5 5.5 5.8 6.6 7.0 7.0 2,590 acid swelling

Looking at the experimental results of Table 7, in the case of boric acid, the Ca removal rate increases as the content of boric acid increases, but when using 1.0 parts by weight or more, the final pH is lowered to less than 8.0, and it can be confirmed that the problem of deterioration in physical properties occurs during the application of the next process.

In addition, in the case of formic acid, swelling caused by the acid occurs when the amount used is 1 part by weight or more, and the Ca removal effect is better than boric acid because the difference in pH change between processes is large, but the rate of pH change (6.8 → 8.2) during the process is too high. Since boric acid affects physical properties and shape stability, it was confirmed that boric acid is more suitable than formic acid, and it is optimal to use 0.40 to 1.20 parts by weight of boric acid based on 100 parts by weight of lizard nappy.

In addition, it was confirmed that the calcium (Ca) content in the leather (nappy) softened with the optimal composition softener was 2,600 to 2,800 mg/Kg, preferably 2,630 to 2,780 mg/Kg, and the pH of the leather was 8.1 to 8.3. .

Example 3: Derivation of optimal conditions for high-efficiency bleaching treatment

Due to patterns such as rice patterns and spots on the surface of lizard leather, a separate bleaching process is required to realize the original color and improve fastness. In the past, bleaching was performed through chemical treatment such as sodium chloride, and was performed through multiple processes. Examples thereof are shown in Table 8 below. The content in Table 8 below means the amount of input based on 100 parts by weight of leather.

Process Content (parts by weight) ingredient Processing time (minutes) note Primary
bleaching treatment 1,000 water 25℃ 30 NaCl 20 (8 Boume) 5.0 sodium hypochlorite 60 3.0 sodium chlorite 60 Secondary
bleaching treatment 3.0 sodium hypochlorite 60 3.0 sodium chlorite Overnight Dewatering and rinsing tertiary
bleaching treatment 1,000 Water 25℃ 30 NaCl 20min. (8 Boume) 3.0 sodium hypochlorite 60 3.0 sodium chlorite 60 Dewatering and rinsing

The existing bleaching treatment process has a problem in that the bleaching efficiency is low and the bleaching process takes a long time and a lot of chemicals are used because the bleaching process is performed three times. In addition, since a lot of chlorine gas is generated during the process and can adversely affect the working environment, it has emerged as an important problem during bleaching.

(1) Derivation of optimal amount of potassium permanganate in bleach

In the present invention, experiments were conducted to find optimal conditions for performing a one-step bleaching treatment.

Lizard nappies softened with a softening agent containing 0.5 parts by weight of boric acid in Table 7 of Example 2 were prepared.

Then, after adding the lizard napi to the drum, 1,000 parts by weight of water was added to 100 parts by weight of the lizard napi, and then 30 parts by weight of sodium chloride was added at 25 ° C., followed by bleaching for 20 minutes, and then In the contents of Table 9 below, potassium permanganate was added and bleached for 120 minutes, then 10 parts by weight of Na ₂ S ₂ O ₂ was added, bleached for 120 minutes, and then dehydrated and rinsed to perform one-step bleaching. The treated lizard napi was prepared. In addition, the color difference and bleaching degree of the prepared lizard nappy were measured, and the results are shown in Table 9.

division ingredient Content (parts by weight) Processing time (minutes) note color difference degree of bleaching single step
(one-step)
bleaching treatment water 1,000 25℃ - - NaCl 30 20 (8 Boume) permanganic acid
potassium 0 120 77 Inadequate 2 80 Inadequate 4 85 Great 8 83 Great
(Skin damage occurs) Na ₂ S ₂ O ₂ 10 120 - - -

Looking at Table 9, when 0 to 2 parts by weight of potassium permanganate was used during the bleaching treatment, there was a problem that bleaching was insufficient, and when 4 parts by weight and 8 parts by weight exceeding 3.0 parts by weight were used, bleaching was excellent. . However, when 8 parts by weight of potassium permanganate was used, there was a problem of damage to the epidermis of napkins. Through this, it was confirmed that the appropriate use range of potassium permanganate is about 3.0 to 6.0 parts by weight.

(2) Na in bleach ₂ S ₂ O ₂ Derivation of optimal usage

The one-step bleaching treatment was performed in the same manner as above, but the bleaching treatment was performed by varying the Na ₂ S ₂ O ₂ content as shown in Table 10 below.

division ingredient Content (parts by weight) Processing time (minutes) note color difference degree of bleaching single step
(one-step)
bleaching treatment water 1,000 25℃ - - NaCl 30 20 (8 Boume) potassium permanganate 4 120 - - - Na ₂ S ₂ O ₂ 0 120 - 73 Inadequate 5 75 commonly 10 85 Great 15 88 Great 20 8 Great

Looking at Table 10, it was confirmed that excellent bleaching and color difference were obtained when the Na ₂ S ₂ O ₂ content was 10 to 15 parts by weight. On the other hand, when the Na ₂ S ₂ O ₂ content was 5 parts by weight or less, the degree of bleaching was insufficient, and when the Na ₂ S ₂ O ₂ was used in excess of 17 parts by weight, it was confirmed that there was a problem in that the color difference was too low. .

In Table 10, the Na ₂ S ₂ O ₂ content is shown in FIG. 10 a photograph of lizard napi bleached using 10 parts by weight.

Example 4

In Table 10, lizard napi bleached using 10 parts by weight of Na ₂ S ₂ O ₂ was subjected to tanning and retanning using the tanning agent and retanning agent of the composition shown in Table 11 below, A leather fabric was prepared.

Specifically, in Table 10, the bleached lizard nappy using 10 parts by weight of Na ₂ S ₂ O ₂ (1.0 parts by weight based on 100 parts by weight of water) was treated with a small amount of Cr powder. Tanning treatment was carried out, and 3 parts by weight was carried out a second time for 1 hour.

Next, retanning treatment was performed using Mimosa, Quebracho, and Tara. Mimosa, Quebracho, and Tara were mixed and used by 3 parts by weight to supplement the filling, shape stability, and physical properties of leather, and the pH was adjusted to 4.5 ~ 5.5 with sodium bicarbonate and sodium carbonate.

In addition, the results of measuring the heat shrinkage temperature, flexibility, tensile strength and tear strength of the manufactured lizard natural leather fabric are shown in Table 12 below. At this time, tensile strength and tear strength were measured in accordance with KS M 6882, oil and fat content was measured in accordance with KS M 6882, and flexibility was measured in accordance with KS M ISO 17235. In addition, the friction fastness was measured according to KS M ISO 20433.

In addition, the Cr content was analyzed by ICP-OES (Inductively Coupled Plasma-Optical Emission Spectrometer) after acid decomposition of the sample (detection limit = 5mg/kg), and the Ca content was measured by adding 2N HNO ₃ to the sample and then boiling water bath. It was heated for 4 hours in the air, cooled, adjusted to volume with distilled water, diluted to an appropriate concentration, and measured using ICP.

process Content (parts by weight) ingredient time (minutes) note tanning process
and tanning agent
(Tanning) 300 water 30℃,
pH 3.6
~3.8 3.0 Cr-powder 60 3.0 Synthetic fatliquor 30 3.0 Cr-powder 60 0.5 NaHC0 ₃ 30 0.5 MgO Overnight Heat shrinkage temperature measurement, Drain&Rinse, chromium oxide (Cr ₂ O ₃ ) content measurement retanning process
and retanning agents
(Retanning) 100 water 40℃,
pH 4.5
~5.5 3.0 natural tanning agent
(Mimosa, Quebracho, Tara) 30 2 Neutral syntan 20 One Sodium bicarbonate (NaHCO ₃ ) 10 One Sodium bicarbonate (NaHCO ₃ ) 20 0.3 Sodium Carbonate (Na ₂ CO ₃ ) 1/2x30 Dewatering and rinsing In Table 11, the contents are parts by weight of the composition relative to 100 parts by weight of lizard napi.

Heat shrinkage temperature (℃) Friction fastness (grade) Tensile strength (kgf/mm ² ) Tear strength (kgf/mm) case wet 91 4 4 2.7 2.2 Cr content (ppm) Ca content (ppm) Oil content (%) Flexibility (mm) Burst strength (kgf/cm ² ) 2,220 229 1.7 2.4 14.5

Through the above examples and experimental examples, the descaling agent of the present invention and the lizard leather fabric manufactured using the same have excellent mechanical strength such as friction fastness, tensile strength, tear strength, and burst strength while minimizing skin damage. In addition, it was confirmed that high-quality lizard natural leather fabric applied to expensive leather products could be manufactured because it had excellent flexibility and appropriate oil content.

Claims (10)

Step 1 of preparing a soaked lizard hide;
A second step of preparing a napkin from which a skin layer is removed by performing a de-scaling treatment on the soaked lizard hide;
A third step of performing a softening (de-calcium) treatment on the napi from which the skin layer has been removed; and
A method for manufacturing lizard leather fabric through optimization of descaling, di-calcium, and bleaching processes, characterized in that performing a process comprising: 4 steps of bleaching the softened napi. The method of manufacturing lizard leather fabric by optimizing descaling, di-calcium, and bleaching processes according to claim 1, characterized in that a tanning process and a retanning process are further performed. The method of claim 1, wherein the second step,
Step 2-1 of performing a descaling process for 50 to 80 minutes under a drum rotation speed of 3 to 8 RPM and 25 to 35 ° C. after putting the soaked lizard hide and a descaling agent into the drum; and
Step 2-2 of immersing the lizard leather, which has been performed in step 2-1, in an aqueous solution of potassium hydroxide for 50 to 80 hours, and then washing and dehydrating to obtain nappies from which the skin layer has been removed; Characterized by descaling, di-calcium, bleaching process optimization method for manufacturing lizard leather fabric. 4. The descaling, di-calcium, bleaching process according to claim 3, wherein the descaling agent comprises a degreasing agent, sodium hydrosulfide, sodium sulfide and water. Lizard leather fabric manufacturing method through optimization. The method of claim 4, wherein the descaling agent is 0.1 to 1.0 parts by weight of a degreasing agent, 3.0 to 6.0 parts by weight of sodium hydrosulfide, 6.0 to 12.0 parts by weight of sodium sulfide, and 3,500 to 4,500 parts by weight of water, based on 100 parts by weight of lizard hide. A method for manufacturing lizard leather fabric through optimization of descaling, di-calcium, and bleaching processes, characterized in that it comprises as a part. The method of claim 1, wherein the three-step softening (de-calcium) treatment
Step 3-1 of performing a softening process for 100 to 150 minutes at a drum rotation speed of 3 to 8 RPM and 20 to 30 ° C after inputting the skin layer and the softening agent into the drum; and
A lizard leather fabric manufacturing method through optimization of descaling, di-calcium, and bleaching processes, characterized in that it includes; step 3-2 of washing and dehydrating nappies performed in step 3-1. The method of claim 6, wherein the pH change during the softening process of step 3-1 is 6.4 to 8.3,
Calcium (Ca) content in the dehydrated napkin of step 3-2 is 2,600 ~ 2,800 mg/Kg, and the pH of the dehydrated leather is 8.1 ~ 8.3 through optimization of descaling, di-calcium, and bleaching processes Method for manufacturing lizard leather fabric. The method of claim 6, wherein the softening agent is based on 100 parts by weight of Lizard Napi, 2.0 to 3.0 parts by weight of ammonium sulfate, 2.0 to 3.0 parts by weight of ammonium chloride, and 0.1 to 0.6 parts by weight of Lipapron. , Boric acid (boric acid) 0.40 ~ 1.20 parts by weight and 3,500 ~ 4,500 parts by weight of water, characterized in that it comprises descaling, di-calcium, bleaching process optimization through lizard leather fabric manufacturing method. The method of claim 1, wherein the four-step bleaching treatment is performed by a one-step bleaching method,
In the single-step bleaching treatment method, step 4-1 of adding softened nappies and water to a drum and then adding sodium chloride (NaCl) to the treatment for 15 to 30 minutes;
Step 4-2 of adding potassium permanganate to the drum and treating it for 100 to 140 minutes;
Step 4-3 of adding Na ₂ S ₂ O ₂ to the drum and treating it for 100 to 140 minutes; and
Steps 4-4 of washing and dehydrating the bleached nappies;
Steps 4-1 to 4-3 are continuous processes. The method of claim 9, in step 4-1, 800 to 1200 parts by weight of water and 25 to 30 parts by weight of sodium chloride are added to 100 parts by weight of napi in the drum,
In step 4-2, 3.0 to 6.0 parts by weight of potassium permanganate is added to 100 parts by weight of napi in the drum,
In steps 4-3, 8.0 to 17.0 parts by weight of Na ₂ S ₂ O ₂ are added to 100 parts by weight of skins in the drum.

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