Technical Area

The invention relates to a new method for the production of vegan leather (aegiaus), based on olive pomace and vegetable waste, with silicone polymer additives.

State of the Art

Olive oil is recognized as one of the most important fats in terms of human diet and health in terms of its content. Turkiye is one of the top 5 olive oil producing countries in the world considering the 2020 data. Olive oil is extracted from the fruits of the olive tree plant and the olive fruit contains about 20-30% oil. This oil is extracted by various techniques and then a cellulose rich waste is left behind. The waste material in question is called olive pomace. Approximately, 40 units of olive pomace is harvested from 100 units of olives after olive oil extraction. Olive pomace is not a pure substance, it contains around 25% moisture, around 4-8% oil and around 40% cellulose. Olive Pomace can be integrated into polymers as a filler in this form or by subjecting it to various processes.

Dried olive pomace for cellulose purification can first be extracted with a suitable solvent and degreased. The degreased olive pomace is boiled under pressure or in normal atmosphere with a sufficient amount of base to remove lignin, hemicellulose and protein residues. As a result of this process, hemicellulose and lignin pass into aqueous solution as water-soluble salts and proteins are broken down to their amino acids. The remaining material contains a high proportion of cellulose, which can be used in polymers. If desired, it can be subjected to further purification processes. Olive pomace and cellulose extracted from pomace is a quality filler to be used in artificial (synthetic) leather and is a biopolymer compatible with other components of artificial leather. The structure of cellulose is given below.

Structure of cellulose

Artificial (synthetic) leather is also called vegan (aegiaus) leather because it does not contain any animal additives. The main materials used in the production of artificial leather are polymers called polyurethane and polyvinyl chloride (PVC). Unfortunately, these polymers are synthesized from substances extracted from fossil resources such as petroleum. Polyurethanes and PVC are not only not derived from sustainable sources, but also do not decompose easily when disposed of in the environment. The negative impact of petroleum-based polymers, especially on the environment and human health, has led to a growing interest in more ecological products with high biocontent and thus more environmentally friendly and contributing to sustainable development. Therefore, a great deal of research is being conducted on vegan (aegiaus) leathers with a high biocontent, even 100% if possible. What is meant by the term "biocontent" is that the carbon atoms in artificial leather give positive results according to the ¹⁴ C test, in this sense, it is not derived from any fossil source. The ratio of the ¹⁴ C isotope to the normal ¹² C isotope in living organisms is constant and is 1/1x10 ¹² . When the living creature dies, this ratio decreases and is practically 0 in samples older than 50000 years. Therefore, if the ¹⁴ C ratio is 0 as a result of the carbon test, it is concluded that the carbons in this substance are of fossil origin and not of bio origin.

The typical synthetic leather production in the technical field first prepares fluid blends of polymers or prepolymers with or without fillers. Flowability of the mixture is controlled by the amount of solvent. Solvents such as dimethylformamide, dimethylsulfoxide, toluene, isopropanol can be used for this purpose. The polymer blends are simply coated on the lining fabric in a setup shown in Figure 1 , and the coating thickness is adjusted by blades in the feed section. The polymer coated fabric is curing in this way. Other layers and fabrics can be added to the first layer, which is then flattened and tightened by passing through the printing rollers. At each layer addition, the material is cured in the furnace. At the end of these processes, synthetic leather is obtained.

The most commonly used polymers in synthetic leather production are polyurethanes and polyvinylchloride, either pure or in blends. These polymers, as mentioned earlier, are not environmentally friendly materials.

The application numbered TR 2020/20490 describes the vegan leather production method in the patent and literature research on the state of the art. The production method uses kombucha mushrooms as a starting material, according to the reference document. Nothing is mentioned in the document about the utilization of olive pomace.

Consequently, due to the above-mentioned drawbacks and the inadequacy of the existing solutions, a development in the relevant technical field has become necessary.

Figures to Facilitate the Understanding of the Invention

Figure 1 shows an overview of a typical synthetic leather production method.

Reference Numbers

1 Mixture feed

2 Pulling direction

3 Impression cylinder

4 Fabric

5 First layer (interior)

6 Second layer (middle part)

7 Third coat (outer coating)

Brief Description of the Invention

The present invention relates to the production of vegan (aegiaus) leather, which fulfills the above-mentioned requirements, which eliminates all disadvantages and brings some additional advantages. The main purpose of the invention is to obtain and mass produce vegan (aegiaus) leathers in which cellulose obtained from olive pomace, a renewable resource, is used as a filler, high bio-carbon content, and polymeric additives such as polyurethane and PVC are kept to a minimum by using cellulose acetate and silicone polymers.

Another object of the invention is to provide a vegan (aegiaus) leather production method using cellulose acetate, polymeric silicones, which are partially or completely more environmentally friendly. As a result of the trials carried out within the scope of the invention, the synthesis and production of Vegan (aegiaus) leather with a higher biocontent (close to 100%), where cellulose acetate and silicone polymers are used as filler, the amount of polyurethane is at most 10-15%, and cellulose acetate and silicone polymers are substituted for the reduced polyurethane. The end product is a more environmentally friendly product compared to the state of the art.

The invention makes it possible to achieve a vegan leather production process in which cellulose from olive pomace is also used as a filler.

The structural and characteristic features and all advantages of the invention will be more clearly understood with the detailed description given below and therefore the evaluation should be made by taking this detailed description into consideration.

Detailed Description of the Invention

The preferred embodiments of the invention are described in this detailed description only for a better understanding of the subject matter.

The invention relates to a method for the production of vegan leather (aegiaus), based on olive pomace and vegetable waste, with silicone polymer additives. In the inventive method, olive pomace is first dried and degreased. In the next processing step, cellulose is extracted from the olive pomace.

In the process of drying and degreasing the olive pomace, specifically, the raw pomace is extracted, dried and then degreased with a suitable degreasing solvent. It is then boiled with a basic substance to remove hemicellulose, protein and lignin. If necessary, a bleach such as hydrogen peroxide or sodium hypochlorite (bleach) can be used for whitening. One of the important process steps of the invention is the preparation of mixtures to be used for the production of vegan leather. Polymer blends are prepared, preferably in a reactor with a mixer, and the polymer blends may contain the main polymer, a suitable solvent if necessary, filler (pomace cellulose), various auxiliaries (viscosity adjusters, curing agents, etc.) and dyestuffs.

Then, in the finishing step, these mixtures are applied with or without filling, starting from the lining cloth and forming layers. The first of these polymeric layers is applied at the desired thickness with the help of applicator blades on a polyester or cotton or polyacrylonitrile, polyamide etc. fabric used as a lining. It is inserted into a temperature- adjustable furnace by pulling it at an appropriate pace. After the first layer is cured, the second and third layers can be applied. What is meant by curing herein is the volatilization of the solvent or polymerization. If desired, a lining cloth can also be added between these layers.

Examples of the process stages that constitute the vegan (aegiaus) leather production method based on olive pomace within the scope of the invention are as follows. These examples are illustrative of the application and effectiveness of the invention without any restrictive meaning.

Example 1: Extraction of Olive Pomace

A 50-liter reactor (into a sokslet extractor) is added 10 kilograms of dry olive pomace and 30 liters of a low-boiling, low-polarity solvent called degreaser, preferably methylene chloride, ethyl acetate, acetone or diethylether. Flushing is carried out at least twice and up to 30 times depending on the type of rice. The olive pomace, which is degreased at the end of the process, is used in the next stages.

Example 2: Obtaining Pure Cellulose from Olive Pomace

5 kg of defatted dry olive pomace is placed in a 25-liter reactor and boiled with 10 kg of a solution containing 2% to 50% and preferably 5% base by weight for 2 to 10 hours, optimally 4 hours. If very pure cellulose is required, boiling is done under pressure. Olive pomace is boiled under pressure in a pressurized reactor at a minimum of 130 °C and a maximum of 180 °C. If the cellulose still has some color after boiling, it is boiled with a 5% bleach solution. The olive pomace cellulose is then washed with water and press dried. This pure cellulose obtained is used in the following stages.

Example 3: Vegan (Aegiaus) Leather Formula 1 (Inner Coating)

0-10 kg of polyurethane, 0-10 kg of polydimethylsiloxane, 0-5 kg of acrylated epoxide soybean oil are placed in a 25-liter reactor with a mixer, the mixture is mixed for 30 minutes. Then a sufficient amount of viscosity adjuster, 0-0.5 kg of thermal initiator and 0-2 kg of dyestuff are mixed in. This mixture is mixed for about 30 minutes and then loaded into the line with a suitable mixing system.

Example 4: Vegan (Aegiaus) Leather Formula 2 (Medium Coating)

0-10 kg of 30% cellulose acetate dimethylsulfoxide solution, 0-10 kg of polydimethylsiloxane, 0-5 kg of acrylated epoxide soybean oil are placed in a 25 liter reactor with a mixer and the mixture is mixed for 30 minutes. Then a sufficient amount of viscosity adjuster, thermal initiator between 0-0.5 kg, dyestuff between 0-2 kg are added, this mixture is mixed for about 30 minutes and loaded to the line with a suitable mixing system.

Example 5: Vegan (Aegiaus) Leather Formula 3 (Outer Cover)

0-10 kg of polyurethane, 0-10 kg of polydimethylsiloxane, 0-5 kg of acrylated epoxidized soybean oil, 0-5 kg of oleopol or oleomilk, 0-5 kg of polymeric isocyanate are placed in a 50-liter reactor with a mixer and the mixture is mixed for 30 minutes. Then a sufficient amount of viscosity adjuster, 0-0.5 kg of thermal initiator and 0-2 kg of dyestuff are added. This mixture is mixed for about 30 minutes and then loaded into the line with a suitable mixing system.