CH720535A2 - Plasma-treated foamed biogranules - Google Patents

Abstract

A material comprises foamed biogranulate grains, the material comprising a surface, at least part of the surface being subjected to a treatment. The treatment comprises a plasma treatment (10), in particular for hydrophobizing the part of the surface.

Description

Technical area

[0001] The invention relates to material comprising foamed biogranulate grains, wherein the material comprises a surface, wherein at least a part of the surface is subjected to a treatment, in particular a treatment for hydrophobizing the part of the surface.

State of the art

[0002] It has long been known to use foamed biogranulate grains as a material in various fields. The term biogranulate grains refers to both whole and cut (shredded) grains and, in particular, fractions of cut grains.

[0003] Foamed biogranulate grains are understood to mean all foamable grains. A typical example of foamed biogranulate grains is puffed corn (one example of this which is not typically used as a material is so-called popcorn). Rice, wheat, rye, barley, oats, millet, quinoa, spelt, etc. can also be used. The foamed biogranulate grains are produced using a hydrothermal expansion process. The puffing of the biogranulate grains is preferably carried out using the so-called Bichsel process, which is described in detail in patent EP 0 975 238 B1. In variants, biogranulate grains puffed in other ways can also be used. The grain, in particular the corn, can be crushed beforehand. This achieves a better mechanical connection between the puffed grains, especially when producing molded bodies, since these are not round.

[0004] For example, foamed biogranules, in particular puffed corn, are used in loose form as packaging material. It is also known to press and/or glue puffed corn into molded bodies in order to create dimensionally stable components for various applications.

[0005] For example, it is known from EP 2 961 580 B1 (Univ. Göttingen Georg August) to use popcorn in wood and/or composite materials, in particular chipboard and fiberboard, insulation boards and material boards. For this purpose, materials made of shredded lignocellulose-containing material or popcorn are glued with a synthetic or natural binding agent and pressed under temperature and pressure to form composite materials.

[0006] WO 92/04253 A1 (Sommer et al.) further relates to such a packaging material which is biodegradable. Puffed grains, for example puffed corn, puffed rice or puffed wheat, are used for the packaging material. A slurry can be formed with puffed grains and an organic binder such as starch, which is poured into a mold that corresponds to the object to be protected.

[0007] The known materials based on foamed biogranules have the disadvantage that they are typically inadequately protected against moisture and wetness. Foamed biogranules based on corn, for example, in particular have a tendency to soften and become mushy when exposed to moisture. When dried, the particles finally shrink almost to their original size, which is accompanied by a considerable loss of volume. This causes adhesive points or surrounding areas to tear.

Description of the invention

[0008] The object of the invention is to create a material belonging to the technical field mentioned at the outset based on foamed biogranulate grains, which has a better resistance to moisture and generally to polar liquids.

[0009] The solution to the problem is defined by the features of claim 1. According to the invention, at least part of the surface of the material is subjected to a plasma treatment.

[0010] In a method for processing, in particular for hydrophobizing a material, wherein the material comprises foamed biogranulate grains and a surface, at least part of the surface is subjected to a treatment, in particular a treatment for hydrophobizing the part of the surface. The treatment comprises a plasma treatment.

[0011] Plasma treatment is a process for treating surfaces. It is known to subject plastic, metal, glass surfaces, etc. to plasma treatment in order to clean, activate or coat them.

[0012] During plasma cleaning, surfaces are freed from unwanted substances such as dust, release agents, additives, plasticizers and hydrocarbons.

[0013] During surface activation, the surfaces are prepared in order to optimize the subsequent adhesion of printing inks, varnishes, adhesives and coatings.

[0014] It is also known to coat such surfaces with a plasma treatment in order to obtain certain properties, such as better paintability of plastics or better corrosion resistance of metals.

[0015] It has now surprisingly been found that various plasma processes can be used not only on plastics, metals and glass surfaces, but also on surfaces of foamed biogranulate grains - it was generally expected that the foamed biogranulate grains (e.g. popcorn) would not withstand such a process and would be destroyed. Surprisingly, however, the tests have now shown that the foamed biogranulate not only survives the plasma treatment and can therefore retain the essential properties such as dimensional stability and/or flexibility, but also positive effects can be achieved, in particular, for example, hydrophobization of the surface. It should be noted here that due to the diffusion-open structure of the foamed biogranulate grains, the plasma can preferably also penetrate into the foamed biogranulate grain, so that the hydrophobization can preferably be achieved not only on the surface, but also within the foamed biogranulate grain.

[0016] The hydrophobic treatment solves a particularly long-standing problem in the processing of materials comprising foamed biogranulate grains, in particular because it now opens up wide-ranging areas of application that were previously only accessible with difficulty or not at all. The materials comprising foamed biogranulate grains, in particular for example a molded body made from such a material, can now also be used in areas in which the material can come into contact with moisture due to the hydrophobic properties. In particular, corresponding molded bodies can be used, for example, as core material in composite panels, as insulation material and the like, without having to take precautions or restrictions with regard to moisture. Corresponding molded bodies can therefore be particularly durable.

[0017] There are three particularly preferred options for how and when the plasma treatment can be used during the manufacturing process of the material: 1. The foamed biogranulate grains are subjected to a plasma treatment, whereby no processing step takes place between the puffing of the biogranulate grains and the plasma treatment, apart from any regulation of the moisture, in particular a drying step or moistening step. The material is therefore present as untreated foamed biogranulate grains immediately before the plasma treatment. After the plasma treatment, the foamed biogranulate grains are preferably coated with an adhesive. Optionally, the coating can contain other substances in addition to the adhesive, in particular fire retardants, pesticides, etc. If necessary, after intermediate storage as a semi-finished product, the coated, foamed biogranulate grains are combined to form a molded body in which the foamed biogranulate grains are held together by the adhesive. The adhesive may be omitted, particularly if a suitable type of corn is used, such as waxy corn, which is also known as waxy maize and is characterized by a higher amylopectin content. With such a grain, the inherent adhesive (e.g. amylopectin) may be used to bond the foamed biogranulate grains. Such a molded body is fundamentally hydrophobic and thus water-resistant. 2. The foamed biogranulate grains are coated after puffing, particularly preferably with an adhesive, in order to obtain a free-flowing semi-finished product. This coated, free-flowing semi-finished product is subjected to plasma treatment. Immediately before plasma treatment, the material is thus in the form of free-flowing foamed biogranulate grains coated with an adhesive. Optionally, the coating can contain other substances in addition to the adhesive, in particular fire retardants, pesticides, etc. After plasma treatment, the foamed and coated biogranulate grains can be combined to form a molded body, possibly after intermediate storage as a semi-finished product, in which the foamed biogranulate grains are held together by the adhesive. Such a molded body is also fundamentally hydrophobic and thus water-resistant. If the molded body is cut, the cut surface typically has cut foamed biogranulate grains, which are therefore no longer hydrophobic. However, the layer behind the cut foamed biogranulate grains is already undamaged and therefore hydrophobic. 3. The foamed biogranulate grains are coated after puffing, particularly preferably with an adhesive, and then processed into a molded body in which the foamed biogranulate grains are held together with the adhesive. Optionally, the coating can contain other substances in addition to the adhesive, in particular fire retardants, pesticides, etc. Alternatively, the adhesive may be omitted, particularly if a suitable type of corn is used, such as waxy corn, which is also known as waxy maize and is characterized by a higher amylopectin content. With such a grain, the inherent adhesive (e.g. amylopectin, but also with dextrin from normal corn) may be used to connect the foamed biogranulate grains. The molded body is subjected to plasma treatment.

[0018] Other possibilities are also known to the person skilled in the art.

[0019] The plasma treatment is preferably carried out over the entire accessible surface of the material. If the material is in the form of a shaped body, the entire outer surface is preferably subjected to the plasma treatment. If the material is in the form of a free-flowing semi-finished product, the entire surface of the individual foamed and optionally coated biogranulate grains is preferably subjected to the plasma treatment.

[0020] If the molded body is cut according to variants 1 and 2, the cut surface typically has cut foamed biogranulate grains, which are therefore no longer hydrophobic. However, the layer behind the cut foamed biogranulate grains is already undamaged and thus hydrophobic, so that the molded body remains essentially stable. It is also clear to the person skilled in the art that the cut surface can be made hydrophobic, for example by means of further plasma treatment, a suitable adhesive or in some other way.

[0021] In variant 3, however, there is the problem that a cut surface also leads to cut foamed biogranulate grains - but there are no hydrophobized foamed biogranulate grains behind these. This means that after cutting such a shaped body, subsequent hydrophobization of the cut surface is mandatory if the hydrophobic properties are to be maintained.

[0022] Preferably, the treatment includes a plasma treatment with nitrogen plasma. This enabled particularly good hydrophobic treatment to be achieved in the experiments. In variants, the plasma treatment can also be carried out with air, oxygen, argon, CO2 or other gases or gas mixtures known to those skilled in the art. Preferably, the plasma treatment includes a plasma coating of the surface, in particular to produce a hydrophobic layer. The plasma coating can be used to specifically coat the surface of the material with a hydrophobic substance. In variants, the surface can also simply be activated (see below).

[0023] Preferably, a disiloxane, in particular hexamethyldisiloxane (HMDSO), is deposited on the surface with the plasma coating. This achieves a particularly efficient and permanent hydrophobic treatment of the surface. The person skilled in the art is also aware of other substances that can be used to hydrophobicize the surface. In particular, a fluoropolymer and/or a fatty acid film, in particular a stearic acid film, can be deposited on the surface alternatively or additionally with the plasma coating.

[0024] Preferably, the plasma treatment comprises plasma activation, in particular plasma powder activation of the surface. This allows hydrophobization to be achieved by changing the chemical structure of the surface, which in turn can achieve particularly efficient and permanent hydrophobization. Plasma activation can be carried out as an alternative or in addition to plasma coating. In the combination, plasma activation can be carried out in a first step and then plasma coating in a second step. In this case, the surface can be optimized for the subsequent plasma coating with plasma activation, which can achieve further improved long-term stability of the hydrophobization. Furthermore, plasma coating can be carried out in a first step and then plasma activation in a second step. In variants, plasma activation can also be omitted.

[0025] The plasma treatment particularly preferably comprises plasma powder activation, wherein a polymer powder, preferably a hydrophobic polymer powder, is used as the powder. In variants, other powders, such as a polytetrafluoroethylene powder, a polyethylene powder, preferably UHMWPE powder, or mixtures thereof, can also be used.

[0026] It is also preferred that the plasma treatment achieves a thermal and/or chemical modification of the foamed biogranulate grains, in particular of the surface of the foamed biogranulate grains. The plasma treatment can thus achieve, for example, gelatinization of the starch.

[0027] By means of plasma treatment, the number of cycles can be reduced when hydrophobizing the foamed biogranules by freeze thaw cycles.

[0028] Preferably, the foamed biogranulate grains have a coating, the coating comprising an adhesive with which the foamed biogranulate grains can be bonded together in a molded body. The adhesive particularly preferably comprises an epoxy, in particular an epoxidized soybean oil or the like. The coating, in particular with the adhesive, preferably with the epoxy resin, can optionally be achieved by means of a plasma coating. Alternatively, the coating can also be sprayed on or otherwise applied to the foamed biogranulate grains. In variants, the coating can also be omitted. Furthermore, other substances can also be added to the coating, in particular pesticides, fire retardants, etc.

[0029] Preferably, the foamed biogranulate grains are provided with a coating which comprises an adhesive, in particular an epoxy resin, such that the material is present as a free-flowing semi-finished product which can be bonded to the adhesive of the coating to form a shaped body. A polyacrylate can also be provided as a further preferred adhesive. Furthermore, a NISO mixed form can be provided which comprises both polyacrylate and epoxy resin.

[0030] The adhesive can comprise an organic polymer, an organic copolymer or mixtures thereof, wherein the adhesive is in particular bio-based or biological and/or biodegradable or compostable. In variants, the adhesive does not necessarily have to be biodegradable. The adhesive also does not necessarily have to be bio-based.

[0031] Adhesives that can be used include, in particular, thermoplastics, thermosets, thermosets, aminoplasts, phenolic resins, isocyanates, proteins, tannins, starch, synthetic binders or near-natural binders, or mixtures of binders, such as urea-formaldehyde resin, melamine-formaldehyde resin, melamine-reinforced urea-formaldehyde resin, tannin-formaldehyde resin, phenol-formaldehyde resin, polymeric diphenylmethane diisocyanate or mixtures thereof. Alternatively or additionally, polypropylene, polyethylene, polyvinyl chloride, polystyrene, polyacrylate, polyvinyl alcohol, polyvinyl acetate, polyvinyl laurate, polylactic acids (PLA), polyhydroxy acids such as polyhydroxybutyric acid or cellulose derivatives or mixtures thereof. Other adhesives are known to the person skilled in the art.

[0032] Preferably, the proportion of adhesive in the foamed biogranulate (based on the weight of the foamed biogranulate) is less than 10% by weight, preferably less than 5% by weight, in particular less than 1%. In variants, the proportion of adhesive can also be greater than 10% by weight.

[0033] The coating particularly preferably comprises an epoxy resin and a hardener for hardening the epoxy resin, the hardener being encapsulated in such a way that the hardening of the epoxy resin to produce a molded body can be achieved by introducing energy into the semi-finished product, opening the encapsulation and releasing the hardener. This produces a storable semi-finished product which can be combined in a mold to form a molded part without further additives. In variants, the hardener can also be omitted. In this case, the hardener can also be added to the semi-finished product during the production of the molded body.

[0034] It is important to note, particularly in the case of plasma treatment of the semi-finished product already coated with epoxy, that a thermally activatable hardener can optionally be activated by the plasma treatment. It can therefore be advantageous if the hardener is added to the semi-finished product after the plasma treatment. Alternatively, a hardener can be provided which is activated at particularly high temperatures, but preferably below a temperature which can damage the foamed biogranulate grains in an undesirable manner. One such hardener is, for example, dicyandiamide (Dicy), which is activated at a temperature of around 120 °C. This hardener can optionally also be added to the epoxy resin before the plasma treatment, provided that the (cold) plasma heats the material to less than 120 °C. The temperature of the semi-finished product can be controlled, for example, via the power of the plasma and/or the speed of travel of the plasma jet over the semi-finished product. Furthermore, the temperature of the semi-finished product can be controlled alternatively or additionally via convection/mixing of the semi-finished product during the plasma treatment as well as via distance control of the plasma nozzle to the semi-finished product.

[0035] The semi-finished product is preferably free-flowing. This means that the semi-finished product can be stored, poured and transported particularly easily before being used to produce molded bodies. In variants, free-flowing properties can also be dispensed with. In some cases, it may be sufficient if the semi-finished product is merely deformable, in particular plastically deformable.

[0036] In a preferred embodiment, the free-flowing semi-finished product is subjected to plasma treatment. This ensures that a molded body made from it is also hydrophobic within the molded body. On the one hand, this is relevant so that the molded body can be cut - for example on the construction site - without the hydrophobicity of the entire molded body being lost. On the other hand, it can also prevent the molded body from softening from the inside due to water penetrating into the interior of the molded body (e.g. capillary effect).

[0037] Preferably, the free-flowing semi-finished product is combined with the adhesive of the coating to form a molded body, wherein the molded body is subjected to plasma treatment. In principle, both the semi-finished product and the finished molded body can be subjected to plasma treatment. However, plasma treatment of the molded body can also be dispensed with if the foamed biogranulate and/or the coated foamed, free-flowing biogranulate has already been subjected to plasma treatment.

[0038] Preferably, the foamed biogranulate grains in the material comprise a proportion of at least 80 wt.%, preferably at least 90 wt.%, particularly preferably at least 97 wt.%. In a particularly preferred embodiment, the proportion is at least 99 wt.%. Particularly preferably, the material consists exclusively of foamed biogranulate grains with a coating which comprises an adhesive, particularly preferably an epoxy.

[0039] Preferably, the foamed biogranulate grains comprise hydrothermally puffed biogranulate grains, particularly preferably hydrothermally puffed biogranulate grains made from degerminated corn. In variants, rice, wheat, rye, barley, oats, millet, quinoa, spelt, etc. can also be used. Furthermore, degerminating the corn can also be omitted.

[0040] Preferably, the foamed biogranules have a fat content of less than 2% by weight, preferably less than 1% by weight, particularly preferably less than 0.5% by weight. In variants, the fat content can also be greater than 2% by weight.

[0041] Preferably, the biogranulate grains have a water content of 6 - 9 wt.%. This achieves a particularly optimal consistency of the foamed biogranulate grains, namely they have a non-brittle and springy texture and are particularly suitable for the production of molded bodies. In variants, the water content can also be less than 6 wt.% or more than 9 wt.%. The water content can be selected to be particularly low, in particular if components with a particularly low density are desired.

[0042] Preferably, the power of the plasma jet is between 250 watts and 1500 watts, in particular between 300 watts and 900 watts, particularly preferably between 400 watts and 650 watts. In variants, the power can also be below 250 watts or above 1500 watts. The power depends in particular on the width of the jet, the distance of the jet from the material and the speed of the jet over the material.

[0043] Preferably, the jet has a width of 2 to 12 mm, in particular 5 to 8 mm, particularly in connection with the above power and the speed of the jet described below. In variants, the width can also be smaller than 2 mm or larger than 12 mm.

[0044] Preferably, the travel speed of the jet is between 1 and 100 m/min, in particular between 5 and 30 m/min. In variants, the speed can also be less than 1 m/min, in particular when the plasma jet typically has a low power. The speed can also be greater than 100 m/min, which means that it is possible to work with greater power.

[0045] Preferably, the process gas, in particular nitrogen, for example, is introduced at a flow rate between 1 L/min and 100 L/min, preferably between 10 L/min and 60 L/min, particularly preferably between 30 L/min and 45 L/min. In variants, the flow rate can also be less than 1 L/min or greater than 100 L/min.

[0046] Preferably, a solid, in particular for example a polymer or the like, is used for coating or activating the surface with a mass flow between 1 and 200 g/h, in particular between 5 and 80 g/h, particularly preferably between 25 and 50 g/h. The mass flow can also be less than 1 g/h or greater than 200 g/h.

[0047] It is clear to the person skilled in the art that the above parameters, starting with the power and ending with the mass flow, are interrelated. The person skilled in the art can easily carry out the necessary scaling of the parameters if, for example, the width of the plasma jet should be significantly greater than 12 mm, for example 50 mm.

[0048] Preferably, a distance between the head of the plasma device and the material is between 1 mm and 100 mm, preferably between 2 mm and 50 mm, particularly preferably between 10 mm and 30 mm. In variants, the distance can also be less than 1 mm or greater than 100 mm. The higher the temperature of the plasma, the greater the distance can be chosen in order to protect the material. However, a certain "caramelization" of the surface of the foamed biogranulate grains may also be desired. The distance can also be dynamically controlled so that it is increased if undesirable reactions occur or the material is damaged, and reduced if the temperature is too low.

[0049] In a preferred embodiment of the method, the material is subjected to plasma treatment several times. This has the advantage that the power can be reduced, which in turn can protect the material. In variants, the plasma treatment can also be carried out several times.

[0050] In a further preferred embodiment, in the case of plasma treatment of the free-flowing semi-finished product, the free-flowing semi-finished product is circulated. This is preferably achieved by convection, in particular by the process gas, preferably nitrogen. In variants, convection of the material can also be dispensed with. The method can also be carried out in particular with an impingement toaster or a plasma dryer, in particular a conventional dryer with plasma conversion.

[0051] Preferably, cold plasma is generated in the process. This further protects the material. In variants, the cold plasma can also be dispensed with. Instead, for example, a distance to the material can be increased and/or a travel speed can be increased. The person skilled in the art is aware of further optimizations in order to keep a temperature during the plasma treatment as low as possible below 160 °C, preferably below 120 °C. This temperature range is particularly advantageous to maintain with foamed biogranules.

[0052] Preferably, the foamed biogranules are made from sterilized biogranules, in particular sterilized corn. In variants, sterilization can also be omitted.

[0053] The biogranulate grains preferably have a grain size of between 500 µm and 3000 µm, preferably between 800 µm and 1900 µm, before the foaming process. It has been shown that this allows the best results to be achieved in the production of foamed biogranulate grains. The foamed biogranulate grains produced from this have particularly good properties in the production of molded bodies. The grain size is determined by means of sieve analysis, preferably according to the sieve analysis according to DIN 66165, June 2016. In variants, the grain size can also be smaller than 500 µm or larger than 3000 µm.

[0054] Preferably, the grain size of the foamed biogranulate grains is between 1 mm and 30 mm, preferably between 3.5 mm and 6.5 mm, in particular approximately 5 mm. The grain size is also determined here by means of sieve analysis, preferably according to the sieve analysis according to DIN 66165, June 2016. In variants, the grain size of the foamed biogranulate grains can also be smaller than 1 mm or larger than 30 mm.

[0055] Further advantageous embodiments and combinations of features of the invention emerge from the following detailed description and the entirety of the patent claims.

Short description of the drawings

[0056] The drawing used to explain the embodiment shows: Fig. 1 a schematic representation of a process for hydrophobizing a material comprising foamed biogranulate grains.

[0057] Basically, in the figures, identical parts are provided with identical reference symbols.

Ways to implement the invention

[0058] Figure 1 shows a schematic representation of a process for hydrophobizing a material comprising foamed biogranules.

[0059] In step 1, the foamed biogranulate is provided. These are preferably foamed biogranulate grains based on corn. The corn has been previously sterilized and crushed and hydrothermally puffed. Figure 1 now shows several possible steps to obtain a hydrophobic material based on these foamed biogranulate grains.

[0060] In step 10, the untreated foamed biogranulate grains are subjected to plasma treatment. The process gas is nitrogen with a flow rate of 33 L/min. The plasma jet has an output of 500 watts. The speed of the plasma jet relative to the material is 5 m/min. The distance to the material is 15 mm. The material was then placed in water and shows excellent hydrophobicity over a period of days, especially in comparison to the untreated reference sample, which softened in a short time.

[0061] In step 11, the plasma-treated foamed biogranulate grains are coated with an adhesive, in this case an epoxy with an addition of ARADUR® as a hardener, and temporarily stored as a free-flowing semi-finished product. In step 12, the semi-finished product is baked into a molded body. To do this, the semi-finished product is placed in a mold and heated to 100°C. The ARADUR® is activated at a temperature between 60°C and 100°C, which crosslinks the epoxy hardener. Even in this state, the hydrophobic effect is excellent.

[0062] In step 20, the foamed biogranules are coated with an adhesive, in this case an epoxy with an addition of dicyandiamide as a hardener, and fed to the next step as a free-flowing semi-finished product.

[0063] In step 21, the semi-finished product is subjected to plasma treatment. The process gas is nitrogen with a flow rate of 33 L/min. The plasma jet has an output of 615 watts. The speed of the plasma jet relative to the material is 5 m/min. The distance to the material is 15 mm. The hardener is only activated at 120°C. With the process parameters, the material was kept at a temperature of below 120°C so that the epoxy resin did not harden. The material was then placed in water and showed excellent hydrophobicity over a period of days, especially in comparison to the untreated reference sample, which softened in a short time. The softened reference sample was dried as a test - a considerable loss of volume (shrinkage) was found.

[0064] In step 22, the semi-finished product is baked into a molded body. To do this, the semi-finished product is placed in a mold and heated to 140°C. The dicyandiamide is activated at a temperature of 120°C, which causes the epoxy resin to crosslink. Even in this state, the hydrophobic effect is excellent.

[0065] In step 30, the semi-finished product is baked to form a shaped body using the material from step 20, and thus before the plasma treatment.

[0066] In the subsequent step 31, the molded body is subjected to plasma treatment. The process gas is nitrogen with a flow rate of 33 L/min. The plasma jet has an output of 450 watts. The speed of the plasma jet is 5 m/min. The distance to the material is 15 mm. In addition, HMDSO (hexamethyldisiloxane) was added at a material flow of 50 g/h. The material was then placed in water and shows excellent hydrophobicity over a period of days.

[0067] In summary, it can be stated that according to the invention a material comprising foamed biogranulate grains is provided which is hydrophobicized in a particularly effective and efficient manner.

Claims (15)

1. Material comprising foamed biogranulate grains, wherein the material comprises a surface, wherein at least a part of the surface is subjected to a treatment, characterized in that the treatment comprises a plasma treatment, in particular for hydrophobizing the part of the surface. 2. Material according to claim 1, characterized in that the treatment comprises a plasma treatment with nitrogen plasma. 3. Material according to claim 1 or 2, characterized in that the plasma treatment comprises a plasma coating of the surface, in particular to produce a hydrophobic layer. 4. Material according to claim 3, characterized in that a disiloxane, in particular hexamethyldisiloxane, is deposited on the surface with the plasma coating. 5. Material according to claim 3 or 4, characterized in that a fluoropolymer and/or a fatty acid film, in particular a stearic acid film, is deposited on the surface with the plasma coating. 6. Material according to one of claims 1 to 5, characterized in that the plasma treatment comprises a plasma activation, in particular a plasma powder activation of the surface. 7. Material according to claim 6, characterized in that the plasma treatment comprises a plasma powder activation, wherein the powder comprises a polymer powder, in particular a hydrophobic polymer powder. 8. Material according to one of claims 1 to 7, characterized in that the foamed biogranulate grains are provided with a coating which comprises an adhesive, in particular an epoxy resin, such that the material is present as a free-flowing semi-finished product which can be combined with the adhesive of the coating to form a shaped body. 9. Semi-finished product according to claim 8, characterized in that the coating comprises an epoxy resin and a hardener for hardening the epoxy resin, wherein the hardener is encapsulated in such a way that the hardening of the epoxy resin for producing a shaped body can be achieved by an energy input into the semi-finished product, for opening the encapsulation and releasing the hardener. 10. Material according to claim 8 or 9, characterized in that the free-flowing semi-finished product is subjected to plasma treatment. 11. Material according to claim 8 or 9, characterized in that the free-flowing semi-finished product is combined with the adhesive of the coating to form a shaped body, wherein the shaped body is subjected to the plasma treatment. 12. Material according to one of claims 1 to 11, characterized in that the foamed biogranulate grains in the material make up a proportion of at least 90 wt.%, preferably at least 95 wt.%, particularly preferably at least 99 wt.%. 13. Material according to one of claims 1 to 12, characterized in that the foamed biogranulate grains comprise hydrothermally puffed biogranulate grains, particularly preferably hydrothermally puffed biogranulate grains produced from sterilized corn. 14. Material according to one of claims 1 to 13, characterized in that the foamed biogranulate grains have a fat content of less than 2 wt.%, preferably less than 1 wt.%, particularly preferably less than 0.5 wt.%. 15. Method for processing, in particular for hydrophobizing, a material, wherein the material comprises foamed biogranulate grains, wherein the material has a surface, wherein at least part of the surface is subjected to a treatment, in particular a treatment for hydrophobizing the part of the surface, characterized in that the treatment comprises a plasma treatment.