Technical Field

Subject of the invention is related to design and production of a vacuum leather processing system to be developed with the intention to provide a sustainable and environmentally-friendly production technology for textile products, particularly for leather production. The invention is particularly related to developing tanning and dyeing methods which are higher in consumption, shorter timed, more reactive, with a lesser waste volume and pollution load.

State of Art

Today, leather is a very special product which is sought for its high durability and performance properties, suitable for use in many different fields, having sustainability properties and being a modification of a natural byproduct. Nevertheless, adaptation of environmentally-friendly techniques, products and technologies as well as integration of developments in chemical technologies into leather product carry great imporantance to ensure production lives on to future generations in the leather industry which is known by the environmental pollution it causes and which faces an intensive agenda filled with problems related to compliance with ecological criteria.

Manufactured leather is a product made for spoilable raw leather and hides by processing them from natural fibres into spoil-resistant materials, providing a material suitable for making various goods and tools making human life easier. The properties provided by the natural fibre network and tanning processes against environmental and mechanical effects make this product a preferred choice providing long-term user satisfaction in many fields. Today, manufactured leather products are deemed as important luxury goods in many industries including automotive and internal decoration which have a large demand for high standard goods, and it is known the market demand for such products grow day by day. No matter what the production purpose is, the principle of "safe product and safe environment" has gained importance in regards of both environmental health and human health in leather industry in recent years.

In the current state of the art, many natural and synthetic chemicals are used to convert raw leather into manufactured leather in the leather industry. In the 20 ^th century developments in chemical and mechanical industries have expanded the product and production range used in leather manufacture and leather products better satisfying consumer expectation were offered thanks to many properties infused to the products by use of chemicals. Passing through multiple phases in production to provide the expected properties, the leath products are processed by certain amounts of chemicals in each phase. Thanks to tehcnological developments leather products with various enhanced properties like durability, water-repelling, fire-resistance and many other properties are offered to the market. Alongside all these positive effects, chemical products also cause new problems every passing day. Some of the new products which keep appearing and their pollutants have marked negative effects on human health and environment. The hazard posed by chemical materials materialise as damage to human health and environment during their production or use or when they turn into waste. Regulations and restrictions on toxic and dangerous properties of chemicals are implemented to provide protection against their negative effects on human health and environment. In recent years awareness on restricted substances have become more and more imporant in the leather industry.

In conclusion, conduct of serious studies on new, environmentally-friendly, high consumption production systems for the leather industry and comparative analyses on leather products manufactured with such systems have become a necessity.

Purpose of the Invention

Current invention is related to vacuum leather processing machines which are designed to eliminate all problems experiened in current state of the art.

The main purpose of the invention is to apply a certain level of vacuum to leather processing environment in order to increase the mechanical effect to ensure the space between the tight collagen fibres in the three dimensional helical structure of the leather are pulled further apart for better penetration of the applied dyeing and tanning materials into the fibre structure of the leather and being better diffuse into inter-fibre and intra-fibre structure of the leather in a balanced distribution to better bind with the collagen proteins.

Another purpose of the invention is to provide controlled vacuuming of the ambient air in the processing environment during leather manufacture to provide a low pressure environment to ensure applied chemicals penetrates into the fibre structures quicker in order to decrease processing time.

Another purpose of the invention is to decrease atmospheric pressure in the processing environment to provide a frictionless environment and the amount of chemicals consumed according to the mechincal effect in order to decrease the amount of water and chemicals consumed in processing. For example, 80-100 % water and 8-12 % chrome on basis of leather weight are used to achieve the expected leather properties in conventional leather manufacture, and only 70% of the applied chrome penetrates the leather at best. Following an example of 1 tonne of leather material, approximately 100 kgs of chrome is used for the 1 tonne of leather and at least 30 kgs of chrome passes to the waste water in the 1 tonne of water used in processing, thus damaging the environment. Furthermore, optimisation studies on tanning procedures allow performance of tanning with the least amount of water with a 6-7% chrome solution prepared by using water in an amount just enough to carry the chrome into the leather fibres. In addition, dyeing process using the least amount of water can also be performed by dissolcing the dye only in enough water to carry the dye into the fibres and by processing at high pH without performing the pickling process using 100% water, 10% salt and 2% formic acid-sulphuric acid combination based on leather weight.

The leather production processes subject to the invention use supplementary chemicals to ensure high consumption of tanning substance and best penetration of dye substance into the leather fibres in tanning and dyeing phases by leaving a residue containing APEO, etc. The reaction environment provided by the invention design allows decreased use and/or elimination of these substances. In addition, improvement of the reaction environment for leather production provide savings in water, chemicals and supplementary chemicals, leading to a decrease in the waste water amount and pollution load delivered to the waste water treatement facility, providing energy savings and thus decreasing waste treatment costs. Through all these savings it is also intended to decrease total operation costs. The manufacturing system to be developed will allow production of leather goods at least equal to those manufactures with conventional systems in regard of properties like softness, flexibility, durability, resistance and fastness.

Converting leather, a natural material, into durable, resistant and high performance luxury goods required by various sectors at industrial volumes using clean technologies will establish the infrastructure for sustainable production in leather industry.

Detailed Description of the Invention

The vacuum leather processing machine and method subject to the invention should be assessed in light of the images listed below in order to allow a better understanding of the innovations made to achieve the purposes listed above.

These images include;

Image - 1 Circuit diagram view of the vacuum leather processing machine subject to the invention.

Numbers are indicated on the image in order to allow a better understanding of the vacuum leather processing machine subject to the invention. These include;

1. Drum

2. Blower

3. Booster

4. Heat exchanger

5. Water reservoir

6. Pump

7. Cooling unit

8. Waste/recycling reservoir

9. Output line

The drum(l), as one of the main components of the vacuum leather processing machine, allows recirculation of a liquid in the system using a drive system which can operate on single or double rollers or bronze beds. The main body of the drum(l) can be produced in various sizes, in cylindrical, hexagonal, octagonal or any other geometric shape according to the intended operation type. The drum(l) can be installed on top of a concrete base or steel construction pods. The drum(l) can be used as a leather tanning machine, leather processing mixer, wet(humid) curing machine, dry curing machine or leather drum drying machine. The drum(l) can be made of five different materials, comprised of stainless steel, polypropylene, polyester, wood or polyethlylene. Body of the drum(l) circulates external oil or water or mechanically recirculates internal process water through a heater with its double walled structure.

In the vacuum leather processing machine and method subject to the invention the leather or textile product intended for convection or modification is placed into the drum(l). The product placed in the drum(l) is washed at a temperature level between 25° C to 50° C according to the amount of product or the intended formula. The washing time varies according to factors like the type, the size or the colour of the product placed in the drum(l). Some example operations are shown in Table-1 and Table-2 below. The data provided in Table-1 and Table-2 are example operations only intended for information purposes and do not cover the entirety of the invention.

The washing operation makes the product in the drum(l) soften and pulls the fibres of the product apart to a degree. The increase in temperature and moisture in the drum(l) achieve in result of washing negatively affects the application of vacuum in the drum(l). The moisture is remoevd from the drum(l) through a valve placed in the internal wall of the drum(l) for this purpose. Thus, an environment convenient for establishing a vacuum is achieved in the drum(l).

A blower(2) connected to the drum(l) is used to help establish vacuum in the drum(l). The blower(2) allow reduction of the internal pressure in the drum(l) to the level of 600 to 750 mmHg. Even when pressure level is reduced with the help of the blower(2) the required level of vacuum cannot be achieve with this alone. At least one booster(3) must be connected to the blower(2) in order to reach the desired level of vacuum. With addition of the booster(3) the internal pressure of the drum(l) is moved from 600 to 750 mmHg level to 750 to 900 mmHg. A vacuum pump can also be used as an alternative to the booster(3). After application of negative pressure, water and chemical materials are sent into the drum(l). With the vacuum applied in the drum(l) all leather tanning procedures including the wetting, liming, pickling, depickling, chorming, retainage, dyeing and wet curing can be performed. As the fibre pores in the product in the drum(l) are sufficiently pulled open with the effect of the vacuum, water and chemicals can penetrate into these pores. The pressure level in the drum(l) should be kepts at a minimum average of 650 mmHg during the process in order to allow the water and chemicals to penetrate into the fibres. Some of the vacuum level is lost during input of water and chemicals into the drum(l). Drive system of the drum(l) can be provided with five different methods, comprising chain gear, steel gear, castermid gear, derlin gear and belt pulley power transfer.

Upon input of water and chemicals into the drum(l) the level of moisture and temperature in the drum(l) rises again. The moisture and temperature levels in the drum(l) can be monitored by the hygrometer and thermometer connected to the drum(l) and adjsuted accordingly from the control panel. The system can measure the temperature and moisture levels in the drum(l) while the drum(l) working during the process and control parameters like process water temperature, chemical material dosaging amounts, water intake amounts and operation time from the control panel. The control panel can be in digital or mechanical structure according to preference.

While the drum(l) is cooled at the outer walls due to the applied vacuum, the temperature inside the drum(l) constantly rises. The water and chemicals inside the drum(l) transition into gaseous phase due to the increasing temperature. The increased level of moisture in the drum(l) constitutes a hazard for the blower(2). The gas particles formed inside the drum are pulled into the blower(2) due to the pressure applied by the blower(2). When gas particles travel into the blower(2) it cannot work at 100% performance and its efficiency is reduced. To prevent this from happening, the control panel will stop vacuum operation when the spot moisture and temperature levels measured by the hygrometer and the thermometer exceeds the preset moisture and temperature levels. Then the water and chemicals which have transitioned into gaseous phase are removed from the drum(l) through the output I i ne(9) connected to the inner surface of the drum(l). The gas particles are conveyed to the heat exchanger(4) through the output line. When they pass through the heat exchanger(4) the gas particles condense and transition to liquid phase. The liquid material generated in this process is transferred to waste/recycling reservoir(8). After this vacuum is again applied into the drum(l) by help of the blower(2) and the booster(3) to bring the internal pressure of the drum(l) to the desired level. When the pressure reaches the desired level the water and chemicals inside the waste/recycling reservoir(8) are redirected into the drum(l) to provide recycling in the system. When the process is concluded waste liquids in lesser amounts in comparison to current state of the art are collected in the waste/recycling reservoir(8). This drum(l) process is repated for each procedure to be applied on the product as well as according to the formula. For the heat exchanger(4) element used in the process plate exchangers or pipe exchanger can be used, and external heating can be provided thorugh heater fluids using resistance heaters. As an alternative, the process water can be connected to a pipe, exchnager or heater tank through a mechanical recirculation system for recirculating heating of the internal process water. As another alternative, a forced mechanical circulation system can be installed to pass the process water in the drum(l) through a dobule walled(hot oil or steam heated) pipe to provide mechanical recirculating heating without using any pump.

Wet curing and dry curing operations can be performed in the vacuum leather processing machine subject to the invention. Connection of a hot air circulation system into the drum(l) is sufficient for enabling such operations.

This application both decreases consumption rate of the water and chemicals sent into the drum(l) to dye the product in the drum(l) and helps the water and chemicals penetrate into all fibres of the product. The decreased amount of water and chemicals consumed in the drum(l) also decreased the amount of waste generated during operation.

It is observed that as pressure drops in vacuum leather processing operation the temperature levels of the machine elements including the drum(l), the blower(2) and the booster(3) also increase. This can lead to damage on the drum(l), the blower(2) and the booster(3) elements. In order to prevent this from happening cooling systems are installed on the outer surfaces of the drum(l), the blower(2) and the booster(3). This cooling system may have a double walled structure according to preference. The water circulating in the cooling system between the two walls of the drum(l), the blower(2) and the booster(3) starts to heat up during the process. The heated water in the cooling system is first passed through the heat exchanger(4) to lose some of its heat and then transferred to the water reservoir(5). After this initial cooling step the water in the water reservoir(5) is moved to the cooling unit(7) by help of the pump(6). After being fully cooled down in the cooling unit(7) the water is returned to the cooling system on the outer surfaces of the drum(l), the blower(2) and the booster(3). These steps are repeated as long as the process continues (see. Image-1).