WO2021112777A1

WO2021112777A1 - Novelty in processing of leather, woven fabric and similar products

Info

Publication number: WO2021112777A1
Application number: PCT/TR2019/051017
Authority: WO
Inventors: Azem Yilmaz ISBECER
Original assignee: Demaksan Deri Insaat Asansor Makina Sanayi Ve Ticaret Limited Sirketi
Priority date: 2019-12-03
Filing date: 2019-12-03
Publication date: 2021-06-10

Abstract

The present invention relates to a vacuum method which enables removing undesirable materials from fiber gaps in fibers of processed products or inserting desired materials into gapped fibers by providing opening more of fiber gaps with regard to initial value of processed products, by reducing the atmosphere pressure in a controlled manner to a predetermined desired amount at the process medium during processing of leather, woven fabric and similar products.

Description

NOVELTY IN PROCESSING OF LEATHER, WOVEN FABRIC AND SIMILAR PRODUCTS

Technical Field The present invention relates to a vacuum method which enables removing undesirable materials from fiber gaps in fibers of processed products or inserting desired materials into gapped fibers by providing opening more of fiber gaps with regard to initial value of processed products, by reducing the atmosphere pressure in a controlled manner to the predetermined desired amount at the process environment during processing of leather, woven fabric and similar products.

Prior Art Leather is an essential product made of natural material. During leather manufacturing process, various types of leather and chemicals are used. During this manufacturing period, high amounts of water is wasted. Thus, leather industry has had an image of being contaminated and environmentally hazardous industrial field for years. Processing stages of leather manufacturing, which are not so clean, high amount of waste water and foul smell arising during processing, which are characteristics of this branch, have been a negative impact with regard to environmental aspects. During leather manufacturing waste products such as lime, arsenic, ammonium salts, sulfuric acids, chromium salts, herbal waste are released into the environment. 200 kg of finished hide is obtained as a result of processing canned raw hide of 1000 kg. In return, during processing stages, a leather waste of 600 kg is obtained. Further, 50 tons of water are used for tanning. This water is discharged from the processing plant as 50 m³ of waste water with high contamination rates.

Generally, in leather manufacturing, water is required at every stage of manufacturing process and these process steps are called soaking processes.

Brine is a process performed with salt in order to prevent microorganisms harming skin protein after a short period of cooling of hide process.

The initial process carried out on the raw hide is soaking. The duration of the soaking process varies depending on the amount of chemical used in the brine. The first thing done by the leatherworker is to remove the salt from the hide, and accordingly restore the amount of water lost during the skinning process. The soaking process also ensures that hides are cleansed from water- soluble proteins and dirt. The soaking process is adjusted in accordance with the brine form of the raw hide. This adjustment is performed by means of implementing the soaking time, water temperature and mechanical processes in various ways.

Lime pit is a stage wherein hide layer is revealed by removing upper and lower portions of the hide and fiber texture of the hide is prepared for a subsequent tanning process which will be performed later. The lime pit method must be suitable for properties of the desired leather. Calcium hydroxide, sodium sulfide, sodium hydrosulfide and other excipients are used. Generally, it continues for 16 to 18 hours. In practice, there are two types of dehairing processes which are hair loosening and hair melting.

Hides are washed and hair particles are removed therefrom following deliming, bating (Enzymatic Softening) and lime pit processes. Neutralization of hides located at the lime pit are performed by means of deli ing and bating processes. Following the deli ing operation, an efficient bating operation ensures isolating fibers from one another (allowing fibers to move), clearing tanned surface from hair, epidermis and pigment residues, having a thin and good appearance on tanned face of hide. The more the hide is desired to be soft, the more intense the process of bating becomes. Most of the enzymes used in bating process are obtained from pancreas, bacteria and fungi and proteolytic enzymes.

Degreasing is the process carried out with the aim of removing undesirable oil particles from the skin. This operation is performed leather cabinets. Specific surfactant soaps, weak alcohols, weak solvents and salt are used during this process. A large amount of water is used during washing.

After picklage (brining) descaling and bating processes, the pH value of the ready-to-tan tola is reduced to below 3 by way of acids such as formic acid and sulfuric acid for tanning. During this process, sodium chloride (salt) is used to prevent acidic swelling. Picklage treatment is not less than 2 hours depending on thickness of the hide. In the picklage process, the basic amino groups of the skin are converted to the ammonium salt.

Tannage (tanning), leather tanning process is the action of processing raw hide. Tanning is a method of leather processing in which skin is subjected to physical and chemical processes and made to be used as an industrial product. As a result of these methods, the raw material of the leather is transformed into the desired shape and model by transforming from clothing to upholstery, accessories to decor products, carpet to postage, into different leather goods.

The skin is of a protein structure, it putrefies in the humid environment with the effect of microorganisms. If the tola is dried, the fibers adhere to each other and become hard, gaining a fragile and transparent structure. If treated with high temperature water, it becomes like glue. Thus, tanning is the process of treating the hide in suitable conditions with sufficient number of tanning agents at suitable amounts. The task of tanning is to separate the fibers from each other and give the fiber bundles mutual strength. The tanned skin becomes unaffected by microorganisms and temperature.

Mineral (Chromium, Zirconium etc.) tanning process, which has been a preferred method of leather tanning in the beginning, utilizes chromium or chromium salts during the tanning process. The leather treated with these materials softens and gains different individual colors. Because of the harm to human health and nature, this technique has been abandoned in time.

Another tanning method is vegetable tanning. In this technique, treatment is performed by using natural plants. Acacia, carob and oak wood are among the most commonly used plants.After the process, a flexible, brown skin appears. Hides that have been treated in this way since very early years and hardened by water are often used in bookbinding and armors. A tanning method is a physical tanning technique in which external factors are disabled and hide is only obtained after fracture of the connective tissue in the skin. After the process, the hide softens and has a light structure. When it enters water, it deteriorates and hardens. The aim of the aldehyde tanning method is to obtain white and cream-colored leather. Oxazolidine and glutaraldehyde components are used during the aldehyde tanning process. This type of tanning process reveals the types of leather commonly used in leather clothing, car upholstery and baby shoes. In the alum (salting) tanning process, protein components, which are natural products, are processed by using flour and eggs together and tanning process is performed. Since the products used in this process, which is performed to obtain a hard skin, are natural, and therefore decaying occurs when it enters the water. White skin is obtained by means of an artificial tanning method. The artificial tanning process came into being when once products used in vegetable tanning process have turned into a shortage of raw materials. Tanning is carried out by using fragrant polymers such as Novolac and Neradol.

For a very long time, particulars such as high amounts of wastewaters, releasing of environmentally hazardous substances in to wastewaters, causing harm to atmosphere and water resources, eliminating these wastes in a way which would not bring any harm to the environment have been considered and studied. Alternative tanning materials have been tried all around the world as wastewater treatment costs are high in addition to environmental damage and health hazards caused by chromium which is included among the raw leather processing materials as well as it is anticipated that leather products will have to comply with far stricter quality requirements when compared to ones that are existing today.

Also, a sequence of processes is performed on the leather for dyeing the leather in the desired color. For example, in the current leather soak processing technology, the leather is taken into a drum, followed by the addition of water and the corresponding soaking chemicals. However, it takes up to 24 hours for the hide to obtain the desired wetness for dyeing. Then the dyeing process is carried out.

On the other hand, too much water is consumed in leather processing. For example, minimum 250-300 tons of water is consumed in an average leather processing factory. At the end of the process, the water used becomes wastewater containing harmful chemicals. In other words, both large amounts of clean water are consumed, and harmful wastewater emerges almost as much as the water consumed.

One of the processing methods was removing dirt from woven products. To that end thereof, women washed clothes by the river, by boiling the clothes and beating them with knobs for cleaning in earlier times. This process, even if they were not aware of it, allowed fibers to diverge from one another, thereby removing unwanted dirt from the fibers. This method later inspired the creation of blades in the tub of washing machines. These blades in the washing machine tub act as a knob by hitting the laundry inside the tub while the tub is rotating. These blades, which act as knobs, open between the fibers of the laundry, thus allows for cleaning the laundry by facilitating the removal of the dirt between the fibers.

This method was also used in the tubs of leather cabinets, which were later used for leather processing. The leather cabinet has been used to beat the product inside while the tub is turning and to diverge the fiber structure of the product thereby allowing the chemical prepared enter between the fibers so that it can be used for cleaning or dyeing.

In today's technique, dyeing remains only on the upper portion of the skin. This is due to the fiber structure of the skin. As illustrated in Figure 1, elastin and collagen type 1, which form the epidermis of the skin, because of a tight fiber structure, the dye covers the surface of the skin as a layer. The fact that dyes do not penetrate the hide and cannot reach to collagen type 3 (corium) fibers, prevents the dye from dispersing evenly, causes using more dye and accordingly more chemicals for the dyeing process, induces the paint to remain as merely a layer on the surface, hardens the hide, thereby causing the hide to wear out sooner.

Therefore, blades located in tubs fail to provide desired results as these blades located within tubs cannot sufficiently diverge the fibers for processing both woven fabric and leather products. Even though the blades in the tub are opened between the blows and the fibers, the desired materials cannot penetrate into the place of the air bubbles as much as desired because the existing air bubbles between the fibers cannot be eliminated completely.

Similar problems are also encountered in washing processes of woven fabrics. The nature of the fabric occasionally necessitates using potent chemicals in order to remove stains permeate between fibers. However, as these chemicals cause damage to the product, they also induce a series of problems such as producing even more chemical wastes as it is the case with leather dyeing, and penetrating the human body.

In consideration of the information as well as examples provided above, processing of leather, woven fabric and similar products is performed by means of adding substances between product fibers or by removing undesired materials therebetween.

When these processes are performed with techniques employed today as disclosed above, as fibers cannot be penetrated in a sufficient way while these processes are being performed, these processes generate high amounts of chemical wastes, pollute water and cause excessive energy consumption, and accordingly, cause damage to the national economy, and result in environmental pollution, thereby necessitating the use of a novel method.

Objects of the Invention

The object of the present invention relates to a vacuum method for removing the undesired materials from fibers in the processed products or inserting desired materials between fibers during processing of leather, woven fabric and similar products, by reducing the atmospheric pressure in the process environment to a predetermined desired amount, thereby allowing the processed products to diverge more than the initial value of the fiber spaces.

Another object of the present invention is to inject desired substances between fibers in considerably less amount of time and by consuming much less chemicals and water as cleansing of undesired substances can be performed in a short span of time and by using much less chemicals and water, when specific amount of vacuum is applied to the process medium in the processing of leather, woven fabric, and similar products, fibers which are in a tight formation as illustrated in Figure 2, are separated as shown in Figure 3. Another object of the present invention is to obtain better results in a shorter period of time and with less chemicals by ensuring that dermis and the lower portion of the hide gets separated even further during the processing of leather products.

Yet another object of the present invention is to achieve a more balanced dispersion in the process and to ensure that less chemicals are utilized by means of ensuring that the process penetrates into collagen type 3 (dermis) fibers in leather processing.

Another object of the present invention is to prevent the hardening of the hide, thereby preventing the hide from wearing out sooner by means of the controlled vacuum.

Yet another object of the present invention is to ensure that the desired results are achieved in briefer period of time by means of the controlled vacuum. By means of the reduced pressure medium created by vacuuming of air in the process medium with desired amount in a controlled manner during processing of leather, woven fabric and similar products; · Manufacturing period is shortened,

• Time is saved,

• Manufacturing cost is reduced,

• Less water and chemicals are used during the process,

• Less amount of waste materials is generated, · Natural structure of the product is preserved,

A lighter product is obtained as there is no layer formation.

Detailed Description of the Invention

Description of the Figures: FIGURE 1 illustrates the sectional view of the hide fiber structure.

FIGURE 2 illustrates the structure view of leather and woven fabric fiber.

FIGURE 3 illustrates the fiber structure of leather and woven fabric product separated with vacuum.

FIGURE 4 illustrates the exemplary vacuum tub.

FIGURE 5 illustrates the cross-section of the leather dyed in the prior art.

FIGURE 6 illustrates the section of the leather dyed with the vacuum technique. Reference Numerals:

1. Vacuum Holes

2. Drum

The present invention relates to a vacuum method which enables removing undesirable materials from fiber gaps in fibers of processed products or inserting desired materials into gapped fibers by providing opening more of fiber gaps with regard to initial value of processed products, by reducing the atmosphere pressure in a controlled manner to a predetermined desired amount at the process environment during processing of leather, woven fabric and similar products.

When the skin section is examined, the structure consists of three separate layers. The outermost layer, called the epidermis or upper skin, contains hair, wool and nails.

The dermis layer, which is essential in leather manufacturing, is the middle layer. The dermis layer consists essentially of collagen fiber tissue. The lowest layer is called the lower skin and constitutes 85% of the total skin thickness.

The present invention provides a better opening of the dermis and lower skin fibers during the processing of leather products, thereby providing better results with less chemicals in a briefer period of time. Thus, by giving minimum waste to the environment and reducing production costs, added value is provided to enterprises. Reduction of chemical materials results in less toxic and allergenic effects of leather and woven fabric products during human use.

During processing of leather and similar products, the process area (tub and drum, etc.) is brought to the desired atmospheric pressure with the help vacuum, and the fiber gaps of the product in the process are spaced more than the initial state of the product. In the meantime, the air particles between the fibers are ejected from the fibers. When the product processing is performed to add a substance (dye or chemical) to the product, the desired material is easily placed between the fibers which are opened more, and the air bubbles are ejected. If the product is processed for cleaning, it is easier to remove undesirable substances from the fibers that are gapped more than the initial state.

When the exemplary process is considered as leather dyeing, after selecting the leather to be dyed, respective chemicals are added to said drum (2) according to the present formula prepared based on the size and type of the skin. Alternatively, the chemicals prepared according to the prior present recipe can first be added to the drum (2) and then placed into the leather drum (2).

Subsequently, controlled vacuum is applied into drum (2) in a rate determined in accordance with the type of skin placed therein, the amount of chemical to be added, and with the volume of the drum (2).

When vacuum is applied into the drum (2) at a predetermined rate, the gaps of the skin fibers which are previously and normally in a tight state (at normal atmospheric pressure) are opened. In other words, by removing the air within the drum (2) by means of vacuum at a certain extent outside the drum (2), the skin fibers are loosened and the air particles between the fibers are removed and gaps are opened between the fibers. Thus, the chemical in the drum (2) can penetrate into the skin.

At the end of the process, atmospheric air, i.e. the air present in the medium, is fed back into the drum (2) by means of vacuum holes (1). Thus, the pressure in the drum (2) returns to its normal state. In the experimental study, 35-40 kg of chemicals and 3000 kg of water were used for 100 kg leather from raw leather till the end the cabinet dyeing process. In the conventional method, 55-60 kg of chemicals and 5000 kg of water are used for 100 kg of leather.

According to these results, 5000 kg of waste water is released to the environment in the conventional method, while 3000 kg of waste water is discharged to the environment in the vacuum method, and the amount of chemicals in the waste water decreases as a result of the further binding of chemicals to the skin in the vacuum method.

As with all chemical production methods, the vacuum method is an important gain in energy and labor savings by the reduction in production time due to the fact that it occurs under constant pressure, temperature and humidity. While the conventional method requires 15-16 days as of the raw leather state to the end of the cabinet dyeing, 10-12 days are enough for the vacuum method.

Conventional processing of leather, woven fabric and similar products carried out in summary by production machines performing rotating motion or having agitators thereof which are under constant pressure, fixed temperature and humidity during the process. The aim herein is to insert the chemicals between the fibers of leather, woven fabric and similar products by mechanical action or to remove undesired materials out of the fibers. In the present invention, vacuum method is added to conventional method in order to allow the fibers of leather, woven fabric and similar products to move on each other so that the desired materials can easily enter between the fibers or to provide removal of unwanted materials therefrom.

Figure 5 illustrates the cross-section of the skin which has been dyed by the conventional method existing in the prior art. When the skin section is examined, it is seen that the dye remains in the upper layer (dermis) of the skin.

Figure 6 illustrates the cross-section of the skin that has been dyed by the inventive vacuum method. As the fibers are gapped more than normal, it is seen that the coloring agent penetrates the lower skin layer of fibers.

The process of opening the fiber spaces by bringing the medium pressure in the leather processing area to a predetermined low atmospheric pressure value can be applied at all stages of the leather processing process.

Another exemplary process is the washing of woven products, after selecting the woven product to be washed, respective fluids and/or chemicals are added to said drum (2) in accordance with the formula prepared according to the size and type of the woven product and based on the volume of the drum (2).

Then, controlled vacuum is applied to the drum (2) in a rate determined in accordance with the type of the woven fabric placed therein, as well as with the amount of fluid and/or chemical to be added and with the volume of the drum (2). When the vacuum is applied, the fibers of the woven product, which are previously i.e. normally in a tight state (at normal atmospheric pressure), are opened. In other words, by removing the air in the drum (2) by vacuuming to the outside of the drum (2), the fibers of the woven product are loosened and the air particles between the fibers are removed and gaps are opened between the fibers. Thus, by means of the chemical in the drum (2), undesired substances between the fibers are ejected through the fiber gaps.

At the end of the process, atmospheric air, i.e. the air present in the medium, is fed back into the drum (2) by means of vacuum holes (1). Thus, the pressure in the drum (2) returns to its normal state.

The scope of protection of the present application is defined in the following patent claims and by no means the present application can be limited to those described in the above given lines for illustrative purposes only. It is evident that a person skilled in the art can demonstrate the novelty disclosed in the invention using similar embodiments and/or apply this embodiment to other fields of similar purpose used in the art. It is therefore apparent that such embodiments will be lacking the novelty criteria claimed in the present invention and particularly criteria of surpassing the state of the art.

Claims

1.A vacuum method applied to process medium during processing of leather, woven fabric and similar products, characterized in that it enables removing materials from fiber gaps in fibers of processed products or inserting desired materials into gapped fibers by providing opening more of fiber gaps with regard to initial value of processed products, by reducing the atmosphere pressure in a controlled manner to the predetermined desired amount at the process medium.

2 . A vacuum method implemented in processing of leather, woven fabric and similar products characterized in that the atmospheric pressure in the tub and/or drum (2), used during the process, is brought to desired value by applying a vacuum into the tub and/or drum (2).