Binders, methods for their production and uses of the binder

Abstract

A method for producing a binder, wherein an animal hide is subjected to a tanning process for the production of leather using at least one vegetable tanning agent to open the molecular structure of collagen fibers contained in the animal hide, wherein at least one additive is added to the animal hide during tanning, wherein the vegetable tanning agent used is quebracho, mimosa, oak, an extracted polyphenol compound or an extract of olive leaves containing phenolic compounds, wherein the binder is obtained by grinding the leather to a particle size of less than 5 mm, wherein the collagen fibers in the leather are made hydrophobic by adding hydrophobized highly dispersed silica and / or synthetic X-ray amorphous silicon dioxide, and wherein the ground leather is chambered and covered with cork.

Description

[0001] The invention relates to a binder, in particular for hydrocarbon-based media, for example oil. The invention further relates to a method for producing the binder and a use of the binder.

[0002] In practice, a wide variety of oil binders are known, consisting of or manufactured from inorganic or organic materials. Oil binders made from inorganic materials include, for example, those of natural silicate origin, such as diatomaceous earth or diatomaceous earth, pumice, or natural materials processed into silicate products, predominantly in granular form.

[0003] Oil binders formed from organic material can consist of, for example, plastics such as polyurethane or polypropylene, or of natural raw materials such as peat or cork.

[0004] Oil-absorbing granules are produced by granulating and drying a mixture of inorganic, clay-containing organic binder and a lipophilic water-repellent powder. The inorganic powder comprises a mixture of slag sludge, rock flour sludge, paper pulp or fly ash, and clay. A mixture of sawdust, vermiculite, or perlite with the inorganic powder increases its porosity. The oil-absorbing granules are sintered and stored or reused after being re-impregnated with lipophilic agents.

[0005] However, all of the aforementioned known oil binders share the characteristic that their production requires complex processes and the use of sometimes relatively expensive materials. Furthermore, the applications of these previously known oil binders and their oil binding efficiency are insufficient due to the sometimes moderate porosity and / or adsorption, as well as the limited binding capacity, of the medium to be absorbed.

[0006] The porosity of these types of oil absorbents makes them a catalyst for flammable liquids, as the larger surface area makes it easier to initiate a combustion reaction (wick effect). Diesel fuel is almost impossible to ignite with a lighter, but if oil absorbent is applied to it, this is easily possible. Due to its lower flash point, this risk is significantly higher with gasoline.

[0007] Oil binders have become indispensable tools in environmental protection, particularly in the case of hydrocarbon-based pollution of water or soil, for eliminating or at least limiting the causes of pollution that lead to, for example, oil spills.

[0008] The technology behind oil / universal absorbents has remained unchanged for decades. Despite proven inadequate technical properties, products of mineral and / or silicate origin still dominate. In addition to these technical shortcomings, the use of these types of products also poses a significant and considerable health risk.

[0009] With these product types currently holding a market share of over 90%, there is an urgent need for action. The remaining 10% market share is distributed as follows: approximately 7% for chemical products – including polyurethanes and polypropylene – and approximately 3% for natural organic products such as peat, cork, etc. Sustainability, environmental protection, and the impact on the climate are clearly negative aspects for these latter products.

[0010] FULLER, HI: The use of floating absorbents and gelling techniques for combating oil spills on water. In: Journal of the Institute of Petroleum, Vol. 57, 1971, No. 553, pp. 35-43. - ISSN 0020-3068 describes the use of floating absorbents and gelling techniques for combating oil spills on water surfaces.

[0011] DE 28 10 140 A1 describes how surfaces and media contaminated with fatty materials such as hydrocarbons, vegetable or animal oils or fats, organic solvents, and other organic compounds can be cleaned by applying leather particles and / or fibers. Leather waste can be reduced to a selected moisture content and then shredded into particles and / or fibers.

[0012] GB 2 595 153 B describes a process for obtaining a modified collagen-absorbing product from leather, comprising the following steps: aerating flat pieces of leather for a period of 15 to 45 days; collecting the pieces with an initial relative humidity of 45% or less; sorting the pieces by size; obtaining pieces with a maximum final length between 0.5 and 1.5 mm; placing the pieces in a drying oven; applying heat in the drying oven so that the pieces are exposed to a temperature of 285°C or less for a specified period; controlling the temperature applied during the period so that the relative humidity in the pieces is reduced to a final value between 0.5% and 5%; reducing the temperature of the pieces to ambient temperature; and obtaining the modified collagen-absorbing product from the leather.

[0013] DE 38 14 220 A1 describes a process for chrome-sparing tanning, wherein the hides are pretreated before tanning with 0.5 to 2 wt.%, preferably 0.7 to 1.2 wt.% of an aldehyde or ketocarboxylic acid, tanned in the usual way and then tanned with 2 to 4.5 wt.% of a mixture of chromium(III) salts, acid-binding agents and aromatic di- or tricarboxylic acids or their salts.

[0014] EP 3 645 754 B1 describes a process for tanning animal hides, comprising the steps of: providing a container containing a pickled hide, a tanning agent and optionally an aqueous solution, wherein the total amount of water in the container does not exceed 110% of the total water that can be retained by the soaked animal hide, and wherein the total amount of tanning agent in the container does not exceed 110% of the total tanning agent that can be retained by the soaked animal hide, and making the animal hide alkaline in order to bind the tanning agent in the animal hide.

[0015] DE 697 04 026 T2 describes a tanning process for producing leathers used in the manufacture of end products requiring high leather shrinkage temperatures on the order of 80°C, consisting of washing the hides in a first step called soaking before tanning, followed by a liming process to enable the separation of the hides into grain-side leather (referred to as grain split) and flesh-side leather (referred to as flesh split) in a subsequent splitting process, wherein the alkaline substances contained in the grain splits, such as fatty lime, are removed by neutralization with an acid in a process called descaling, while the flesh splits are subjected to a pickling process to soften them, after which the subsequent tanning process is carried out in two phases.wherein said process comprises a pre-tanning process prior to the known folding process and a tanning process following the known folding process, wherein at least said pre-tanning process consists of exposing the pickled flesh split and the delimed grain split to the chemical action of a chromium sulfate-free mixture based on aldehydes, tannins and / or acrylic resins, wherein the mixture also contains a mineral substance based on silicon dioxide in colloidal suspension.

[0016] EP 2 215 274 B1 describes a process for tanning hides and skins with tanning agents containing deglycosylated iridoids and / or deglycosylated secoiridoids, excluding tanning agents containing genipin.

[0017] The invention is based on the objective of providing a novel binder, a method for its production, and a use of the binder.

[0018] The problem is solved according to the invention by a method for producing a binder with the features of claim 1, by a binder with the features of claim 8, and by a use with the features of claim 9.

[0019] Advantageous embodiments of the invention are the subject of the dependent claims.

[0020] According to one aspect of the present invention, a method for producing a binder is proposed, wherein an animal hide is subjected to a tanning process for the production of leather using at least one vegetable tanning agent to open the molecular structure of collagen fibers contained in the animal hide, wherein at least one additive is supplied to the animal hide during tanning, and wherein the binder is obtained by grinding the leather to a particle size of less than 5 mm.

[0021] According to the invention, the vegetable tanning agent used is quebracho, mimosa, oak, an extracted polyphenol compound or an extract of olive leaves containing phenolic compounds.

[0022] In one embodiment, the vegetable tannin is or becomes at least partially sulfitated.

[0023] In one embodiment, a bleaching agent, a fat licker, formic acid, a resin, a fungicide or a pre-tanning agent, for example a synthetic pre-tanning agent, is used as an additive.

[0024] In one embodiment, the additive is added to the olive leaf extract during or after the extraction.

[0025] In one embodiment, a polyaziridine, a polyepoxide, an isocyanate and / or a carbodiimide is used in the sulfitation process.

[0026] According to the invention, the shredded leather is chambered and fitted with cork.

[0027] In one embodiment, the proportion of cork in the binder is between 5% and 10%.

[0028] For the present specific application, in addition to one or more of the manufacturing processes mentioned and described above, a further processing step is possible - the drying of the material (residual moisture of 50% to 60%) to achieve a residual moisture of less than 10%.

[0029] For this purpose, the material can be conveyed through two drying tunnels via a conveyor system, such as an automatic rail conveyor. In the first drying tunnel, pre-drying is carried out, for example, using infrared drying at 250°C, to a residual moisture content of approximately 15%. In the second drying tunnel, the material is dried to a lower residual moisture content of less than 10%, for example, using warm air at 150°C.

[0030] In one embodiment, water is removed from the collagen fibers during tanning by drying.

[0031] According to the invention, the collagen fibers in the leather are made hydrophobic during tanning by adding hydrophobized highly dispersed silica and / or synthetic X-ray amorphous silicon dioxide.

[0032] The tannins, through cross-linking, prevent the collagen fibers, which are flexible in their fully hydrated state, from collapsing during drying, with the resulting cross-links acting as spacers. Furthermore, the tannins can coat the collagen fibers.

[0033] According to another aspect of the present invention, a binder is proposed comprising particles of leather with collagen fibers, produced by the method described above.

[0034] According to a further aspect of the present invention, a use of the binder for binding at least one hydrocarbon-based medium, for example oil, is proposed.

[0035] In one embodiment, the binding agent is applied to a body of water on or in which the medium to be bound is located.

[0036] The solution according to the invention provides an ecological, economical, effective and sustainable oil binder for the removal of hydrocarbon-based pollution with extensive application possibilities and high binding capacity for a variety of hydrocarbon-based media.

[0037] Exemplary embodiments of the invention are explained in more detail below with reference to a drawing. The drawing shows: Fig. 1 a schematic structural formula of a complex bond of basic chromium sulfate, which is not used in the invention.

[0038] According to the present invention, a binder containing collagen fibers is proposed for binding media, in particular hydrocarbon-based media. Collagen fibers contain at least carbon, hydrogen, nitrogen, sulfur, and oxygen.

[0039] Thousands of years ago, humankind satisfied its needs for protection, comfort, and security with leather and fur made from the hides and skins of hunted or slaughtered animals. Practiced for millennia, leather production has evolved into a modern, scientifically driven industry. Sophisticated high technology is required to produce leather with excellent properties that meet the highest standards.

[0040] Despite this long tradition and the high level of leather production today, increased environmental awareness, a sharpened focus on ecological shortcomings, and improved analytical methods have led to a critical examination of the ecological aspects of leather production. Chrome tanning, in particular, has occasionally come under criticism because a correct distinction was not made between trivalent (III) and hexavalent (VI) chromium: oxidation states that fundamentally differ in the effects of the respective chromium compounds on living organisms and their physiological role.

[0041] Hides and skins consist of the epidermis (including hair), the dermis (corium, cutis), and the subcutaneous connective tissue (subcutis). Leather is made from the dermis, while fur is made from the epidermis with hair and / or wool and the corium.

[0042] The main component of the dermis, processed into leather and determining its properties, is collagen, a fibrous connective tissue protein with a unique chemical structure. Approximately 1,000 amino acids are linked together to form a long, helically twisted peptide chain, a helix. Three such helices form the collagen molecule, which is about 300 nm long and 1.4 nm in diameter. This molecule forms fibrils, which in turn grow into fibril bundles and fibers. This is how the three-dimensional network of fibers in the dermis is created, which is responsible for the diverse natural properties of leather.

[0043] While the structures of collagen molecules and fibrils are now largely elucidated and their properties understood, their remarkably stable mechanical properties at the level of fibers and tissues are still the subject of intensive research.

[0044] The crucial tanning processes in the conversion of collagen into leather take place in the area of ​​the fibrils.

[0045] Due to its molecular structure and organic nature, collagen fibers have a high affinity for all organic compounds, including hydrocarbons. This property gives them a high oleophilic capacity, enabling them to quickly and reliably absorb and bind all types of hydrocarbons and their derivatives. The result is a product with a high retention capacity for the absorbed hydrocarbons.

[0046] The collagen fibers in leather naturally possess absorbent properties. Tanning processes open the molecular structure of the collagen fibers in fur, leather, or hide. This property is utilized in leather production to introduce specific additives into the hide that are important for its final quality and properties. In this case, this capability is used to remove water from the collagen fibers through drying and to render them hydrophobic, for example, by adding hydrophobic, highly dispersed silica and / or synthetic X-ray amorphous silicon dioxide. Collagen, as a protein, owes its reactivity to tanning agents and most other leather chemicals to its numerous peptide groups, its content of basic and acidic amino acids, and its large "internal surface area," accessible through pores and capillaries.The purpose of tanning is to prevent the collagen, which is flexible in its fully hydrated state, from collapsing during drying and thus becoming parchment-like and hard. Tannins achieve this by cross-linking the collagen structure. This stiffens the fibers and fibrils, preventing them from sticking together during dehydration, and keeping the fiber structure soft. The resulting cross-links also act as spacers. Certain tannins additionally coat the collagenous structural elements. All of this prevents the collagen structure from collapsing, increases its resistance to enzymatic and microbial attack, hydrolysis, and hydrothermal stress, and reduces its swelling capacity.

[0047] Despite significant technological advances, the basic operations of leather production have remained unchanged over the centuries. They begin with the preservation of freshly slaughtered hides and skins. Preservation by salting with common salt is the dominant method. Preservatives can supplement this process if necessary, especially in tropical regions. Drying is now only of minor regional importance.

[0048] Especially in Europe, the processing of fresh cattle hides is playing an increasingly important role: The raw hides are cooled to 4°C immediately after slaughter, mixed with crushed ice, kept cool, and transported as needed, then processed fresh within a few hours. Foregoing salt preservation offers significant ecological advantages, as it avoids salt loads in wastewater. The first processing step in the leather factory is softening. Dirt, preservative salt, and soluble hide components are removed, thus preparing the hides for subsequent processes. These processes include a lime and / or sodium sulfide treatment to loosen and / or destroy the hair and to open up the hide (controlling the leather's softness) in a process called liming, followed by an enzyme treatment in the pickling bath.Through intensive washing and descaling as well as mechanical processing processes, such as fleshing (removing the subcutaneous connective tissue) and splitting to determine thickness, the tannery-ready hide is produced in the water workshop.

[0049] Tanning transforms the collagen of the hide, which is otherwise perishable when wet and hard and tough when dry, into a largely rot-resistant, soft-drying material – leather. Tanning agents that achieve this must be able to react with the collagen and have a particle size of such that they can both penetrate the collagen fibrils and act as cross-links within them.

[0050] According to a non-inventive example, salts of trivalent chromium are used as the tanning agent.

[0051] Since the beginning of the 20th century, trivalent chromium salts, primarily dinuclear chromium(III) sulfates, have steadily gained importance as tanning agents. The binding of these chromium tanning agents likely occurs through complex formation with the side chains of collagen. The chromium salts impart a bluish color to the initially moist semi-finished leather, hence the widespread term "wet blue" for this product. Chrome tanning allows for a wide range of leather properties, particularly in terms of application, technical function as an absorbent medium, and hydrophobicity.

[0052] Fig. Figure 1 is a schematic structural formula of a complex bond of basic chromium sulfate, which is not used in the invention.

[0053] A non-inventive chrome tanning process enables efficient, fast, and cost-effective operation. Due to its advantages, it is now used worldwide for the production of approximately 85% of all leather. Tanning and retanning decisively determine the achievable leather properties. The selection of tanning and retanning agents depends on the intended applications of the leather type to be produced.

[0054] When discussing chrome tanning agents and the chrome tanning of leather, concerns are sometimes raised about the risk of heavy metal contamination, as heavy metals are often automatically equated with toxicity, which is incorrect. It is important to consider the assessment criteria outlined above. Furthermore, it is often overlooked that chromium is a widespread chemical element, chrome-containing objects are ubiquitous, and chromium(III) compounds are present in the air, water, and soil, and even in the human body as a natural component. Chrome tanning agents account for only about 1% of the industrially used chromium.

[0055] Chromium tanning agents are primarily supplied today by the chemical industry in the form of basic trivalent chromium sulfates. These starting materials are byproducts of chromium ore extraction for the metal industry. Therefore, the production of chromium tanning agents does not involve any additional resource depletion. Misunderstandings, and sometimes superficial information, have repeatedly arisen regarding the potential hazards of chromium compounds. A physiological comparison of chromium compounds of both oxidation states shows that, in connection with the production and use of leather, only hexavalent chromium compounds can pose a hazard; trivalent chromium compounds, on the other hand, do not. The incomparably lower toxicity of Cr(III) compounds (basic chromium tanning agents) compared to Cr(VI) compounds has been confirmed in numerous studies.

[0056] Another question is: Does the use of chrome-plated leather products lead to the formation of Cr(VI)? This question can also be answered in the negative, even considering the potential effects of, for example, perspiration (pH between 4 and 7, usually around 4.5). Cr(VI) ions only form at unphysiologically high pH values ​​(> 11.2), as studies with test solutions have shown.

[0057] According to an example of the invention, tannins extracted from plant material, for example quebracho, mimosa or oak, or polyphenol compounds are used, which may optionally or partially be sulfitated. Bleaching agents and fat licks, formic acid, resins, fungicides and / or pretanning agents, in particular synthetic pretanning agents, may be used as auxiliaries.

[0058] Before the development of chrome tanning, tanning with vegetable tannins was by far the most important tanning method. Vegetable tannins are a versatile group of complex compounds, also known as tannins. These are produced in virtually all plants. Tanners are particularly interested in the properties of tannins that protect plants from rot, mold, and browsing damage.

[0059] Vegetable tanning agents are complex in structure and contain many substances that are not directly involved in the tanning process but can significantly influence it. Consistent quality is therefore difficult to achieve. However, vegetable tanning agents offer a major advantage in terms of their compatibility. For specific effects, they can be mixed together or applied sequentially to the same hide. Due to the classic characteristics of vegetable tanning agents, only a very limited range of leathers can be achieved with plant extract tanning. In particular, the limited dyeability and the lower softness compared to chrome-tanned leather are noteworthy.

[0060] To optimize the tanning properties of vegetable tannins, certain chemicals, particularly bleaching agents and / or fat licks, formic acid, resins, fungicides, and / or pretanning agents, such as synthetic pretanning agents, can be added during or after extraction. This form of sulfitation can influence the astringency, solubility, penetration, or color of the concentrated plant extracts. The pretanning and posttanning agents, such as bleaching agents, fat licks, formic acid, resins, fungicides, and / or pretanning agents, especially synthetic pretanning agents, play a particularly important role in the hazardous properties of the ingredients used, especially the tannins, as these are sometimes used in high concentrations in vegetable tanning. The chemicals used in sulfitation, such as polyaziridines, polyepoxides, isocyanates, or carbodiimides, must also be critically examined.Due to the use of predominantly plant-based and completely non-toxic substances, pure vegetable tanning is well suited for the material use of the tanning residues in the biological cycle.

[0061] According to the invention, an extract of olive leaves containing phenolic compounds (for example, wet-green® OBE) is used as the tannin. Excipients used include, for example, formic acid, sodium carbonate, fatty licks, synthetic tannins, and / or fungicides.

[0062] Olive leaf extract containing phenolic compounds, particularly wet-green®, can be used without the use of environmentally and health-damaging tanning chemicals, which are still used in all conventional mass-produced leather manufacturing processes. This is because leather products that come into direct contact with the skin can sometimes contain high levels of toxic hexavalent chromium and other allergens. The olive leaf extract containing phenolic compounds, especially wet-green® OBE, requires only the byproducts of olive cultivation – the leaves. Therefore, no trees are felled and no fields are cultivated to obtain the raw material, meaning there is no exploitation of nature. A plant-based concentrate is produced from an aqueous olive leaf extract, which is neither corrosive nor hazardous.Furthermore, the olive leaf extract, which contains phenolic compounds, especially wet-green® OBE, is free of metals and any chemically synthesized reactive tanning agents. This allows waste products from leather production, such as shavings, to be reintroduced into the value chain.

[0063] For assessing the hazard characteristics of the ingredients in the tanning process using olive leaf extract containing phenolic compounds, particularly wet-green® OBE, the consideration of auxiliary and post-tanning agents is also an important factor. Compared to wet white tanning (e.g., with glutaraldehyde), these are used in reduced quantities and optimized from an ecological perspective through the application of the latest standards. The wet-green® OBE tanning agent, due to the use of olive leaf extract, which is a 100% renewable raw material, is designed for the biological cycle. After tanning, the tanning agent is fully integrated into the product, is therefore completely biodegradable as a biological nutrient, and can be returned to natural cycles.This is the difference compared to previous tanning processes, which theoretically allow for recyclability in some cases, but this was not taken into account from the outset in the design of the tanning agent and the process flows.

[0064] The lack of hydrophobic properties in vegetable-tanned materials, such as wet-green® (Wet Blue is hydrophobic due to cross-linking with chromium), is achieved by adding hydrophobized highly dispersed silica and / or synthetic X-ray amorphous silicon dioxide. This allows the leather to be used and applied to the same extent as chromium-containing materials. The use of hydrophobic vegetable-tanned materials offers ecological and environmental toxicological advantages and results in a significantly lower environmental impact.

[0065] In another example not according to the invention, glutaraldehyde is used as the tanning agent.

[0066] For about 20 years, tanning with glutaraldehyde has played an increasingly important role in the production of chrome-free leather. Its tanning effect results from cross-linking with selected amino groups of collagen. In contrast to the blue-moist wet blue tanning process, leathers tanned in this way are yellowish-white, hence the name wet white. The different binding mechanisms of the three aforementioned tanning agent categories, due to the varying availability of reactive groups in collagen relative to hide weight, necessitate very different tanning agent applications and lead to significantly different amounts of bound tannin.

[0067] The following table compares the different tannins: tannin Type and number of binding partners in collagen, theoretically possible binding in %, based on collagen [molecular weight 350,000] Typical practical application on 100 kg of hide material (flat leather) Plant tannins 3,936 peptide and amino groups / mol collagen; 281% tannin [equivalent weight ≈ 250] 20 to 35 kg tannin extract, ≈17 to 25 kg pure tannin Chromium tannins 476 carboxyl groups / mol collagen; 7% Cr or 10% Cr2O3 6.0 to 8.0 kg basic-resistant chromium tanning extract, ≈1.5 to 2.0 kg Cr2O3 or 1.0 to 1.4% Cr Glutaraldehyde 105 amino groups / mol collagen; 1.5% C5H8O2 1.0 to 2.0% liquid traded product, ≈0.5 to 1.0% C5H8O2

[0068] Tanning and retanning are crucial in determining the achievable leather properties. The selection of tanning and retanning agents depends on the intended use of the leather type being produced.

[0069] The term "wet white" refers to chrome-free (pre-)tanning processes using metal salts (aluminum, titanium, zirconium), aldehydes, or specific syntans. Newer processes (X-Tan, Easy White, zeolite tanning) can also be included in this category. When used as a pre-tanning agent, these compounds stabilize the hide structure to such an extent that mechanical thicknessing processes (folding, splitting) are possible, resulting in chrome-free leather scraps. Following this pre-tanning, a filling retanning process is carried out using vegetable tanning agents, syntans, and polymer tanning agents. The increased prevalence of wet white processes in the last 15 years is largely due to the use of glutaraldehyde or its derivatives. However, the spontaneous formation of higher molecular weight conversion products is possible and is, among other things, responsible for the yellowish color of glutaraldehyde-tanned leather.A welcome side effect of glutaraldehyde pre-tanning is its softening effect when combined with vegetable tannins. Glutaraldehyde is present when the maximum permissible workplace concentration (MAK value) of 0.8 mg / m³ is observed. 3 Unlike formaldehyde, glutaraldehyde is physiologically harmless to air. Furthermore, it is firmly bound within the protein matrix and cannot be released again. The typically used amounts of glutaraldehyde and the controlled pH allow for almost complete depletion and reaction of the astringent glutaraldehyde. Therefore, it is not present in the final product. No particular migration behavior, residual aldehyde, or incompatibility with tanned leather is known.

[0070] Vegetable tanning is more complex than chrome tanning; the temperature control required results in higher energy consumption. Water must be treated in wastewater treatment plants, but does not require special processing like that needed for chrome tanning.

[0071] Glutaraldehyde is no longer detectable in the final product; compostability of synthetically tanned leather is generally possible.

[0072] The lack of hydrophobic properties in Wet White (Wet Blue is hydrophobic due to cross-linking with chromium) is achieved by adding hydrophobized highly dispersed silica and / or synthetic X-ray amorphous silicon dioxide. This allows for the same application and use as for chromium-containing material. The use of hydrophobic Wet White offers ecological and environmental toxicological advantages and results in a significantly lower environmental impact.

[0073] For example, the following processing steps for tanning and mechanical processing may be included in leather production: - Storage and sorting: Raw materials are stored in refrigerated rooms. - Soaking: Soaking removes dirt and preservative salt from the raw material and restores its original water content. - Fleshing: During fleshing, tissue, meat and fat remnants are removed with sharp knives. - Liming: By adding lime and sulfur compounds, the hair is removed from the skin in the liming process. - Splitting: To obtain a uniformly thick grain pattern of a specific thickness, the leather is split. The resulting split leather can be further processed into suede, among other things. - Pickling, soaking, tanning: In pickling and soaking, the hide is prepared for tanning with acid and salt. During tanning, the hide fibers absorb the tanning agents. This transforms the raw hide into leather. - Wilting: The wet leather is drained by wilting. - Sorting: The leathers are sorted according to various quality criteria. - Folding: The grain leather is brought to a uniform thickness. Any unevenness on the reverse side is removed. The leather is then grouped into dyeing batches. Neutralizing, filling, dyeing, and fatliquoring: The acid from the tanning process is first neutralized. Depending on the type of leather, this is followed by filling and dyeing with water-soluble dyes. Finally, the required softness for the finished leather is achieved by adding fats. - Stretching, drying: Three methods are used to dry the leather: Stretching (mechanical pressing of the water), vacuum drying, in which the moisture is removed with negative pressure, and hanging drying, in which the leather is dried by a warm air stream. - Studs: To soften the leather after drying, it is mechanically worked (studded) and prepared for finishing in further work steps. - Finishing: Here, the leather receives its final appearance through a finishing treatment. Priming, coloring, sizing, pressing, and ironing give the leather a glossy or matte, single- or multi-colored, smooth or grained surface, depending on fashion requirements. The art of finishing lies in applying wafer-thin layers to the leather without compromising its appearance or its valued properties such as suppleness and breathability. - Quality control: Quality is checked repeatedly between all work steps. The final inspection verifies whether the individual production batches meet all requirements for the leather type or sample. Leather is also sorted according to various quality characteristics. - Shipping: The leathers are measured electronically, packaged and shipped.

[0074] For the present specific application, in addition to one or more of the manufacturing processes mentioned and described above, a further processing step is possible - the drying of the material (residual moisture of 50% to 60%) to achieve a residual moisture of less than 10%.

[0075] For this purpose, the material can be conveyed through two drying tunnels via a conveyor system, such as an automatic rail conveyor. In the first drying tunnel, pre-drying is carried out, for example, using infrared drying at 250°C, to a residual moisture content of approximately 15%. In the second drying tunnel, the material is dried to a lower residual moisture content of less than 10%, for example, using warm air at 150°C.

[0076] For this specific application, in addition to one or more of the manufacturing processes mentioned and described above, a further mechanical processing step is required – namely, comminution to a particle size of less than 5 mm. Chips can also be used for this process.

[0077] Furthermore, compliance with the parameters listed in the following table is desirable to ensure ecological and environmental toxicological suitability in accordance with the requirements of the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety. This can be achieved by controlling preservation, including the use of natural preservatives, chromium-free collagen fibers, and reducing chlorides and sulfates in the manufacturing process. Solid samples - eluate parameter Unit Assignment values DK I / W** DK II / R*** pH value* (at 25°C) - 5.5 to 13 5.5 to 13 DOC mg / L ≤ 50 ≤ 80 Phenol index mg / L ≤ 0,2 ≤ 50 arsenic mg / L ≤ 0,2 ≤ 0,2 Lead mg / L ≤ 0,2 ≤ 1 cadmium mg / L ≤ 0,05 ≤ 0,1 copper mg / L ≤ 1 ≤ 5 nickel mg / L ≤ 0,2 ≤ 1 mercury mg / L ≤ 0,005 ≤ 0,02 zinc mg / L ≤ 2 ≤ 5 chloride mg / L ≤ 1500 ≤ 1500 sulfate mg / L ≤ 2000 ≤ 2000 Cyanide, Ifs. mg / L ≤ 0,1 ≤ 0,5 fluoride mg / L ≤ 5 ≤ 15 barium mg / L ≤ 5 ≤ 10 chrome mg / L ≤ 0,3 ≤ 1 molybdenum mg / L ≤ 0,3 ≤ 1 antimony mg / L ≤ 0,03 ≤ 0,07 selenium mg / L ≤ 0,03 ≤ 0,05 Total dissolved solids content mg / L ≤ 3000 ≤ 6000 * Requirements for oil binders: pH value 4 to 11 ** DK I / W: Landfill class I, limit value for bodies of water *** DK II / R: Landfill class II, limit value for road

[0078] On the other hand, the fiber is conditioned by the industrial process, which creates spaces, to act as a strong absorber and adsorber. Finally, the fiber is highly hydrophobic, so that even in the presence of water, the sorbent exhibits selective behavior and absorbs only hydrocarbons and not water. When the fiber comes into contact with hydrocarbons, the hydrocarbons are immediately absorbed by the hydrophobic molecules in the center of the fiber.

[0079] Furthermore, a solution for the long-term use of collagen fibers on bodies of water is proposed. The material is used, in particular, to fill pads (cushions) and / or booms (oil booms, elongated cushions). The pads can be divided into chambers for better and more effective distribution of the absorbent.

[0080] According to the invention, the material is additionally treated with non-economically usable cork offcuts to improve its buoyancy. This prevents the product from sinking to the water's surface. At the same time, it is kept at an ideal immersion depth to absorb the maximum amount of hydrocarbons. The cork content is, for example, between 5% and 10%.

Claims

[1] A method for producing a binder, wherein an animal hide is subjected to a tanning process for the production of leather using at least one vegetable tanning agent to open the molecular structure of collagen fibers contained in the animal hide, wherein at least one additive is added to the animal hide during tanning, wherein the vegetable tanning agent used is quebracho, mimosa, oak, an extracted polyphenol compound or an extract of olive leaves containing phenolic compounds, wherein the binder is obtained by crushing the leather to a particle size of less than 5 mm, wherein the collagen fibers in the leather are made hydrophobic by adding hydrophobized highly dispersed silica and / or synthetic X-ray amorphous silica, and wherein the crushed leather is chambered and fitted with cork. [2] Method according to claim 1, wherein the vegetable tannin is or becomes at least partially sulfitated. [3] Method according to any of the preceding claims, wherein the additive used is a bleaching agent, a fat lick, formic acid, a resin, a fungicide or a pre-tanning agent. [4] Method according to any of the preceding claims, wherein the additive is added to the olive leaf extract during or after the extraction. [5] Method according to any one of claims 2 to 4, wherein a polyaziridine, a polyepoxide, an isocyanate and / or a carbodiimide is used in the sulfitation. [6] Method according to one of the preceding claims, wherein the shredded leather is dried in particular by infrared drying and / or by warm air. [7] Method according to any of the preceding claims, wherein the proportion of cork in the binder is between 5% and 10%. [8] Binder comprising leather particles with collagen fibers, produced by the method according to any of the preceding claims. [9] Use of the binder according to claim 8 for binding at least one hydrocarbon-based medium. [10] Use according to claim 9, wherein the binder is applied to a body of water.

Images