DE102024120431A1 - Abrasives and methods for producing a support material or for reinforcing an abrasive - Google Patents

Abstract

An abrasive is proposed, comprising an abrasive grain (12), a carrier material (16) for the abrasive grain, and a reinforcement. The carrier material (16) comprises killed mycelia (20). Furthermore, a method for producing the carrier material or the reinforcement is proposed.

Description

The invention relates to an abrasive with abrasive grain and a carrier material for the abrasive grain, as well as a method for producing a carrier material or a reinforcement of an abrasive.

So-called coated abrasives are well-known in practice. Colloquially, these are often referred to as sandpaper or grinding wheels and consist of abrasive grains bonded to a sheet-like backing material. In the case of sandpaper, this backing is flexible and foldable, while in the case of a grinding wheel, it is comparatively rigid. For example, it is known to manufacture the backing from a vulcanized fiber material, which exhibits high strength in terms of breaking load, tensile strength, and tear resistance. However, the disadvantage of a vulcanized fiber backing is that the availability of the raw materials required for its production fluctuates considerably, and the resulting abrasive is expensive. Furthermore, vulcanized fiber has the disadvantage of deforming under humid conditions.

The invention is based on the objective of creating an abrasive designed according to the type mentioned in the introduction, which has high load-bearing capacity, is ecologically and economically sustainable, and is characterized by low manufacturing costs. Furthermore, the invention is based on the objective of creating a method for producing a carrier material or a reinforcement of such an abrasive.

These problems are solved according to the invention by the abrasive having the features of claim 1 and by the method having the features of claim 8.

According to the invention, an abrasive is proposed comprising an abrasive grain, a carrier material for the abrasive grain and a reinforcement, wherein the carrier material comprises killed mycelia.

The core of the invention lies in the fact that the carrier material is inoculated with mycelia or fungal hyphae, which reinforce the carrier material. The mycelia or fungal hyphae increase the load-bearing capacity of the carrier material with regard to breaking load, tensile strength, and tear resistance. Fungi and their mycelia are inexpensive and available in sufficient quantities, so that the abrasive according to the invention can also be manufactured cost-effectively by using mycelia for the carrier material. Furthermore, the mycelia are biodegradable. Therefore, the abrasive designed according to the invention also meets high ecological and sustainability standards.

The fungal species or mycelial species that can be used include, in particular, Pleurotus spp. (all species within the genus Pleurotus, especially Pleurotus Ostraetus), Ganoderma spp. (all species within the genus Ganoderma, especially Ganoderma Lucidum) and Schizophyllum spp. (all species within the genus Schizophyllum, especially Schizophyllum commune).

Pleurotus species grow relatively quickly and can produce large quantities of mycelium-based material in a short time. They can grow on various substrates, including agricultural waste. They readily adapt to different conditions. Ganoderma species can also grow on various substrates. Schizophyllum species are characterized by rapid growth.

The abrasive according to the invention is designed in particular such that the carrier material comprises the reinforcement. It is also conceivable that the reinforcement alone forms the carrier material. The mycelia can form the reinforcement or be a component of the reinforcement.

In a preferred embodiment of the abrasive according to the invention, the carrier material comprises fibers and/or cellulose and/or paper and/or a fabric.

These components can be part of the reinforcement. Natural and/or synthetic fibers can be used.

Preferably, the mycelia penetrate the fibers and/or the pulp and/or the paper and/or the fabric, i.e., the mycelia or fungal hyphae form a three-dimensional network in the substrate material, which gives the substrate material high resilience with regard to breaking load, tensile strength and tear strength.

In principle, the substrate can be coated or equipped with an additional binder. For example, the binder may be a resol. If the substrate consists of fibers and/or cellulose and/or paper and/or fabric, the binder, particularly a resol, can permeate these elements.

In a preferred embodiment of the abrasive according to the invention, the carrier material forms a substrate on which the abrasive is arranged via a bonding agent. The abrasive is then a so-called SAU (abrasive on a substrate). (Backing). This can be designed as a grinding wheel or grinding disc, which exhibits a certain degree of flexibility. It is also conceivable that the SAU forms grinding flaps that are part of a flap grinding wheel, or a grinding belt that can be used in a belt sander. The SAU can also be part of a flap wheel or mop wheel, or a flap pin or mop pin.

Furthermore, in the case of a SAU (abrasive grain), the abrasive grain may be coated with a top layer, which may, for example, contain a stearate.

The carrier material of the abrasive according to the invention can also be a carrier disc that includes the reinforcement with the mycelia and on which, for example, abrasive flaps are arranged that encompass the abrasive grain. In such an abrasive designed as a flap disc or abrasive mop disc, the abrasive grain is thus indirectly connected to the carrier material via the backing of the abrasive flaps.

Furthermore, it is also conceivable that the abrasive according to the invention has a composite material as a carrier material, which is composed of mycelia-free material and mycelia-reinforced material.

In another alternative embodiment, the abrasive grain is distributed within the carrier material. For example, the abrasive is then designed as a grinding wheel, cutting wheel, or the like, in which the carrier material forms a matrix for the abrasive grain. In this case, the carrier material reinforced by the mycelia can thus serve as the bonding material for the abrasive grain.

In a further special embodiment of the abrasive according to the invention, which is designed as a so-called bonded product, for example in the form of a grinding disc or cutting disc, the carrier material, which may comprise phenolic resin or the like as a binder for the abrasive grain and in which the abrasive grain is embedded, can be provided with at least one layer of paper, cellulose, fibers and/or fabric, which is permeated with mycelia and which forms the reinforcement, in particular also additionally or instead of a previously used glass fiber layer.

Another embodiment of an abrasive according to the invention can include so-called mushroom leather as reinforcement. This material is used as a vegan leather substitute and comprises the killed mycelia. Mushroom leather is essentially a sheet material that can include natural polymers, fibers, and fungi, or can consist of pure fungal material. It is conceivable that the mushroom leather could form both the backing material and the reinforcement of the abrasive, or constitute a reinforcing layer within the backing material.

In the method designed according to the invention, by which the carrier material and/or the reinforcement of the abrasive can be produced, a base material is provided that comprises fibers, i.e., natural fibers and/or synthetic fibers, and/or cellulose and/or paper and/or a fabric. The base material is inoculated with, in particular, still living precursor mycelia. The base material inoculated with the precursor mycelia is then cultivated under defined environmental conditions so that the base material is permeated by the growth of the precursor mycelia. The mycelia thus form a network in the base material. Subsequently, the mycelia of the infiltrated base material are killed, so that the carrier material or the reinforcement is provided. For this purpose, the infiltrated base material is, for example, exposed to elevated temperatures. This stops the growth of the mycelia. In addition, the mycelia are completely killed, so that a dimensionally stable network of mycelia results, which ensures the load-bearing capacity of the carrier material or the reinforcement.

The cultivation of the initial mycelia or the mycelia is preferably carried out at temperatures between 5 °C and 40 °C. A relative humidity of 50% to 95% is advantageous.

Furthermore, it can be advantageous to keep the _CO2 saturation of the ambient atmosphere below 2%, preferably below 0.5%, which promotes healthy and efficient growth of the mycelia.

In this context, it can be important to ensure adequate ventilation of the environment during cultivation so that the _CO2 concentration can be kept low and good air circulation is maintained. For example, the mushroom species Pleurotus spp. are particularly sensitive to high _CO2 concentrations, which is why good ventilation is recommended during fruiting body formation.

Furthermore, it can be advantageous to use a light source to which the material is exposed to promote growth.

When using the mushroom species Pleurotus spp. (oyster mushrooms), favorable mycelial growth occurs at 20°C to 25°C and a relative humidity of 85% to 95%. Favorable fruiting body formation occurs at 10°C to 20°C and a relative humidity of 85% to 95%. Humidity of 85% to 95% is required. Diffuse light or indirect sunlight is needed during fruiting. Approximately 12 hours of light per day is ideal.

When using the mushroom species Ganoderma spp. (Reishi mushrooms), favorable mycelial growth occurs at 20°C to 25°C and a relative humidity of 85% to 95%. Optimal fruiting body formation occurs at 10°C to 20°C and a relative humidity of 85% to 95%. Ideally, light is also used for fruiting body formation, but less intensely than with the mushroom species Pleurotus. Diffuse light or indirect sunlight is sufficient.

It should always be ensured that all mycelia are killed during the process according to the invention, so that no living mycelia or fungal spores are transferred to the workpiece when using the resulting abrasive. The complete killing of fungi and fungal spores depends on several factors, including temperature and exposure time. Generally, fungi and their spores can be killed at temperatures between 120°C and 180°C. For example, dry heat (oven or dry sterilizer) can be used, whereby temperatures of approximately 160°C for at least 2 hours may be required to completely kill the fungi and spores. Alternatively, moist heat (autoclaving) can be used, whereby temperatures of 121°C under saturated steam at a pressure of approximately 1.03 bar for at least 15 to 30 minutes may be sufficient to kill the fungi and their spores.

It is important to note that the chosen temperatures must ensure that both vegetative fungal cells and their resistant spores are killed. Different fungal species and spores can exhibit varying degrees of heat resistance, which is why the values mentioned should generally be considered only as guidelines.

In order to improve the growth of the initial mycelia in the base material, in a preferred embodiment of the method according to the invention, the base material is moistened before or after being mixed with the initial mycelia.

Furthermore, the base material, which may include fibers and/or pulp and/or paper and/or fabric, can be mixed with a nutrient solution for the fungal mycelia before cultivation.

• Makronährstoffe:
  1. 1. Kohlenstoffquelle:
     • o Glucose oder Saccharose: 10-20 g/L (abhängig von der Pilzart)
  2. 2. Stickstoffquelle:
     • ◯ Ammoniumsulfat ((NH₄)₂SO₄): 1-5 g/L
     • ◯ Harnstoff: 0.5-2 g/L
  3. 3. Phosphorquelle:
     • o Kaliumdihydrogenphosphat (KH₂PO₄): 1-2 g/L
  4. 4. Kaliumquelle:
     • ◯ Kaliumchlorid (KCl): 0.5-1 g/L
• Mikronährstoffe:
  1. 1. Magnesium:
     • o Magnesiumsulfat (MgSO₄·7H₂O): 0.5-1 g/L
  2. 2. Kalzium:
     • o Kalziumchlorid (CaCl₂): 0.1-0.5 g/L
  3. 3. Eisen:
     • o Eisensulfat (FeSO₄): 0.01-0.05 g/L
  4. 4. Mangan, Zink, Kupfer:
     • o Manganchlorid (MnCl₂), Zinksulfat (ZnSO₄), Kupfersulfat (CuSO₄): jeweils 0.001-0.005 g/L
• Zusatzstoffe:
  • • Vitamine: Pilze benötigen oft B-Vitamine, insbesondere Thiamin (Vitamin B1) und Biotin (Vitamin B7). Diese können in sehr geringen Mengen (Mikrogramm pro Liter) zugesetzt werden.
  • • Aminosäuren: In einigen Fällen können Aminosäuren wie L-Glutamin oder L-Asparagin als zusätzliche Stickstoffquellen hilfreich sein.
• Weitere Überlegungen:
  • • pH-Wert: Der pH-Wert der Nährstofflösung ist vorteilhafterweise leicht sauer, idealerweise zwischen 5.5 und 6.5.
  • • Sterilität: Die Nährstofflösung wird vorzugsweise sterilisiert, um Kontamination durch unerwünschte Mikroorganismen zu vermeiden.
• Beispielsweise kann eine Nährstofflösung eingesetzt werden, die berechnet für 1 Liter folgendes enthält:
  • • Glucose: 20 g
  • • Ammoniumsulfat: 2 g
  • • Kaliumdihydrogenphosphat: 1.5 g
  • • Kaliumchlorid: 0.5 g
  • • Magnesiumsulfat: 0.5 g
  • • Kalziumchlorid: 0.2 g
  • • Eisensulfat: 0.02 g
  • • Manganchlorid: 0.002 g
  • • Zinksulfat: 0.002 g
  • • Kupfersulfat: 0.001 g
  • • Thiamin: 0.01 mg
  • • Biotin: 0.01 mg
  • • Rest Wasser

The nutrient solution for the growth of fungi in fungus-based materials should contain a balanced mix of macro- and micronutrients that meets the specific requirements of the fungi, in particular:

• Macronutrients:
  1. 1. Carbon source:
     • Glucose or sucrose: 10-20 g/L (depending on the mushroom species)
  2. 2. Nitrogen source:
     • ◯ Ammonium sulfate ((NH ₄ ) ₂ SO ₄ ): 1-5 g/L
     • ◯ Urea: 0.5-2 g/L
  3. 3. Phosphorus source:
     • o Potassium dihydrogen phosphate (KH ₂ PO ₄ ): 1-2 g/L
  4. 4. Potassium source:
     • ◯ Potassium chloride (KCl): 0.5-1 g/L
• Micronutrients:
  1. 1. Magnesium:
     • o Magnesium sulfate (MgSO ₄ ·7H ₂ O): 0.5-1 g/L
  2. 2. Calcium:
     • o Calcium chloride (CaCl ₂ ): 0.1-0.5 g/L
  3. 3. Iron:
     • o Iron sulfate (FeSO ₄ ): 0.01-0.05 g/L
  4. 4. Manganese, zinc, copper:
     • o Manganese chloride (MnCl ₂ ), zinc sulfate (ZnSO ₄ ), copper sulfate (CuSO ₄ ): 0.001-0.005 g/L each
• Additives:
  • • Vitamins: Mushrooms often require B vitamins, especially thiamin (vitamin B1) and biotin (vitamin B7). These can be added in very small amounts (micrograms per liter).
  • • Amino acids: In some cases, amino acids such as L-glutamine or L-asparagine can be helpful as additional nitrogen sources.
• Further considerations:
  • • pH value: The pH value of the nutrient solution is advantageously slightly acidic, ideally between 5.5 and 6.5.
  • • Sterility: The nutrient solution is preferably sterilized to avoid contamination by unwanted microorganisms.
• For example, a nutrient solution can be used which contains the following per liter:
  • • Glucose: 20 g
  • • Ammonium sulfate: 2 g
  • • Potassium dihydrogen phosphate: 1.5 g
  • • Potassium chloride: 0.5 g
  • • Magnesium sulfate: 0.5 g
  • • Calcium chloride: 0.2 g
  • • Ferrous sulfate: 0.02 g
  • • Manganese chloride: 0.002 g
  • • Zinc sulfate: 0.002 g
  • • Copper sulfate: 0.001 g
  • • Thiamine: 0.01 mg
  • • Biotin: 0.01 mg
  • • Remaining water

It goes without saying that this recipe can be adapted depending on the chosen mushroom type and the specific requirements of the cultivation process.

In a specific embodiment of the method according to the invention, the base material infiltrated with the mycelia is pressed and/or post-processed by cutting and/or punching before drying. The base material can thus be brought into a defined shape, analogous to papermaking. A pressure of 50 to 2000 kN/ ^m² may be required during pressing.

As in papermaking, a pressure of approximately 300 to 1500 kN/ ^m² can be used for wet pressing. If a kallander process is used for pressing, a pressure of 50–500 kN/ ^m² may be sufficient.

To further improve the material properties of the carrier material produced according to the invention, it may be advantageous to add a binder to the base material.

Furthermore, the provided substrate or reinforcement can be coated or impregnated with a binder. This binder is, for example, a phenolic resin.

In a further special embodiment of the method according to the invention, the abrasive grain is mixed into the base material, so that the base material containing the mycelia or fungal hyphae forms the binding agent for the abrasive grain.

In an alternative embodiment of the method according to the invention, the carrier material is processed into a carrier plate of a flap disc, wherein the abrasive grain is a component of abrasive flaps that are applied to the carrier plate.

Further advantages and advantageous embodiments of the subject matter of the invention can be found in the description, the drawing, and the claims. The scope of the invention includes all combinations of at least two features disclosed in the description, the claims, and/or the figures; that is, each feature discernible from the description, the claims, and/or the figures can, on its own, be part of the claimed subject matter, independent of any further features and/or specifications disclosed in the respective context.

• 1 einen Schnitt durch ein Schleifmittel nach der Erfindung, und
• 2 einen Schnitt durch ein Trägermaterial des Schleifmittels nach 1.

Exemplary embodiments of the subject matter of the invention are shown schematically simplified in the drawing and are explained in more detail in the following description. It shows:

• 1 a cut through an abrasive according to the invention, and
• 2 a cut through a carrier material of the abrasive 1 .

In 1 Figure 10 depicts an abrasive designed as a grinding wheel, which is a so-called coated abrasive and comprises abrasive grain 12 that can be made of diamond, cubic boron nitride (CBN), silicon carbide, corundum, zirconium corundum, and/or ceramic corundum. The abrasive grain 12 is bonded by means of a bonding agent 14 to the upper surface of a carrier material 16, which forms a disc-like, flexible base for the abrasive 10. Alternatively, the carrier material 16 can also be a rigid disc.

The carrier material 16, which is in 2 The material shown in isolation comprises a fabric 18 made of natural fibers, for example hemp, flax, sisal, or the like, which is mixed with a binder. Furthermore, the fabric 18, whose fibers are at least partially aligned parallel to the plane of the fabric 18 as indicated by arrow X, is permeated with mycelia 20. The mycelia 20 form a network within the carrier material 16, which increases its resistance to breaking load, tensile strength, and tear strength. The mycelia 20 that are killed thus form branched fungal hyphae, which, together with the fabric 18, reinforce the abrasive 10.

The production of the carrier material 16 is carried out by first providing the fabric 18 formed from natural fibers and then mixing it with starting mycelia or fungal spores, a nutrient solution, and the binder. The fabric 18 is also moistened. The prepared fabric 18 is then cultivated at a defined temperature and humidity until the initial mycelia have colonized the structure as desired, i.e., formed a network. The mass is then cut to the desired width, pressed, and dried. The drying process and the resulting exposure to heat completely kill the mycelia of the network. This provides the substrate for the abrasive 10, in which the fabric 18, together with the mycelia, forms a reinforcement.

Following the production of the carrier material 16, the binder 14 can be applied to it using special application methods, and the abrasive grain 12 can then be applied over the binder 14. After the binder 14 has hardened, the abrasive 10 can be finished, i.e., cut to size.

In an alternative embodiment of the method according to the invention, natural fibers, such as hemp fibers, are provided as short or long cuts and moistened. The moistened natural fibers are mixed with fungal spores, which form initial mycelia, and optionally with a binder and/or a nutrient solution. The resulting mass is cultivated under defined environmental conditions, i.e., at a defined temperature and humidity, so that the initial mycelia can optimally colonize the fiber slurry forming the mass. The mass colonized with mycelia is then punched out to form discs. The discs are pressed into shape and dried so that they form backing plates for flap discs, each representing a substrate material. During this process, the mycelia are killed. They form a reinforcing network or reinforcement within the volume of the respective backing plate.

Reference symbol list

10

Abrasives

12

abrasive grain

14

binder

16

Carrier material

18

tissue

20

Mycelia

Claims (16)

Abrasive comprising abrasive grain (12), a carrier material (16) for the abrasive grain and a reinforcement, characterized in that the carrier material (16) comprises killed mycelia (20). Abrasives Claim 1 , characterized in that the reinforcement and/or the carrier material (16) comprises fibers and/or pulp and/or paper and/or a fabric (18). Abrasives Claim 2 , characterized in that the mycelia (20) penetrate the fibers and/or the pulp and/or the paper and/or the fabric (18). abrasives according to one of the Claims 1 until 3 , characterized in that the carrier material (16) is a substrate on which the abrasive grain (12) is arranged via a binder (14) and which comprises the reinforcement. abrasives according to one of the Claims 1 until 3 , characterized in that the carrier material is a carrier plate on which at least one grinding element comprising the abrasive grain is arranged and which includes the reinforcement. abrasives according to one of the Claims 1 until 5 , characterized in that the carrier material (16) and/or the reinforcement comprises/includes a binder. abrasives according to one of the Claims 1 until 6 , characterized in that the mycelia (20) form the reinforcement or are part of the reinforcement. A method for producing a carrier material (16) or a reinforcement of an abrasive (10) comprising abrasive grain (12), comprising the following steps: - Providing a base material comprising fibers and/or pulp and/or paper and/or a fabric (18); - Inoculating the base material with precursor mycelia; - Cultivating the base material inoculated with the precursor mycelia under defined environmental conditions such that the base material becomes infiltrated by mycelia (20) through the growth of the precursor mycelia; - Killing the mycelia (20) of the base material infiltrated with mycelia (20) so that the carrier material (16) or the reinforcement is provided. Procedure according to Claim 8 , characterized in that the base material permeated with mycelia (20) is heated to kill the mycelia (20). Procedure according to Claim 8 or 9 characterized in that the base material is moistened before or after being mixed with the initial mycelia. Procedure according to one of the Claims 8 until 10 characterized in that a binder is added to the base material and/or a binder is added to the provided carrier material or reinforcement. Procedure according to one of the Claims 8 until 11 characterized by the fact that a nutrient solution is added to the base material. Procedure according to one of the Claims 8 until 12 characterized in that the base material permeated with the mycelia is pressed and/or cut and/or punched. Procedure according to one of the Claims 8 until 13 , characterized in that the carrier material (16) forms a substrate onto which the abrasive grain (12) is applied. Procedure according to one of the Claims 8 until 14 characterized by the fact that the abrasive grain is mixed into the base material. Procedure according to one of the Claims 8 until 15 , characterized in that the carrier material is processed into a carrier disc of a flap disc, wherein the abrasive grain is a component of abrasive flaps that are applied to the carrier disc.