Sealing element suitable as hydrogen barrier

Abstract

The invention relates to a sealing element which is suitable as a hydrogen barrier and comprises a base material. The invention also relates to a matrix material for fiber composite materials comprising a base material. The invention is characterized in that the sealing element or the matrix material contains a plasticizer, nano-silicon dioxide, aluminum powder and zinc powder.

Description

[0001] Sealing can be used as a hydrogen barrier

[0002] The invention relates to a seal, a method for producing the seal, a matrix material for fiber composite materials, and a method for producing the matrix material, wherein the seal and the matrix material can be used as a hydrogen barrier.

[0003] As we transition to renewable energy sources, hydrogen is becoming increasingly important as an energy source. Hydrogen can be produced in locations with high renewable energy yields and transported from there to urban areas where the energy is primarily consumed. The energy can also be easily stored in the form of hydrogen. However, this transport and storage requires containers and pipelines through which the hydrogen is transported or stored. Such containers and pipelines are typically made of steel or can be made of fiber-reinforced composite materials.

[0004] The hydrogen atom is the smallest atom in the periodic table, so it places special demands on the materials from which the containers or pipes for the hydrogen are made, as its size tends to penetrate materials such as steel or fiber composites.

[0005] The propensity of a material to absorb or transmit hydrogen can be determined using permeability measurements according to DIN EN ISO 17081 and EP 3 553 210 Al. A material sample is placed between two electrodes, and a current flows between the two electrodes as hydrogen diffuses through the sample. The higher the measured current, the greater the hydrogen diffusion through the sample, and vice versa. In steel and fiber-reinforced composites, significant hydrogen diffusion through the material occurs.

[0006] Once hydrogen has penetrated the steel grades commonly used in tank and pipeline construction, it changes the crystal structures of the steel, resulting in mechanical weakening. Fiber-reinforced composites with a matrix made of, for example, epoxy resin, tend to become brittle. Thus, tanks and pipelines made of steel or fiber-reinforced composites lose their mechanical strength over time and must be replaced.

[0007] The underlying object of the invention is therefore to provide a seal and a matrix material for fiber-reinforced plastics which have the highest possible diffusion resistance or permeability resistance to hydrogen in order to increase the service life of containers and pipelines, and at the same time are inexpensive to manufacture and easy to process.

[0008] This object is achieved by the subject matter and methods having the features of the independent claims of the present application. Further, particularly advantageous embodiments of the invention are disclosed in the respective subclaims.

[0009] It should be noted that the features listed individually in the claims can be combined with one another in any technically reasonable manner (even across category boundaries, for example, between methods and devices) and demonstrate further embodiments of the invention. The description further characterizes and specifies the invention, particularly in conjunction with the figures.

[0010] It should also be noted that a conjunction "and / or" used herein between two features and linking them together is always to be interpreted in such a way that in a first embodiment of the subject matter according to the invention only the first feature can be present, in a second embodiment only the second feature can be present, and in a third embodiment both the first and the second feature can be present.

[0011] The seal according to the invention, usable as a hydrogen barrier, with a base material, is characterized in that the seal comprises plasticizers, nano-silicon dioxide, aluminum powder, and zinc powder. The seal is suitable as a barrier for hydrogen, meaning that the hydrogen can essentially not penetrate the seal. "Essentially not penetrate" means, in the context of the application, that the hydrogen penetrating the seal corresponds to less than 5%, preferably less than 2%, more preferably less than 1% of the amount of hydrogen that would otherwise have penetrated the surface to be sealed without the seal.

[0012] The sealant can be used as a barrier to hydrogen because the hydrogen molecules are adsorbed by the sealant and / or because they cannot penetrate the sealing material in the first place. Thus, materials such as steel or fiber composites can be sealed with the sealant, preventing hydrogen from reaching the steel or fiber composite via the sealed surface, thus preventing damage to the materials caused by hydrogen.

[0013] A dispersion base, which is often used in facade paints, can serve as the base material. This allows the sealant to be applied very easily to the surfaces to be protected, as is usual with facade paints. When the sealant has dried, its protective effect is fully present, but it can also be present in its still-liquid state.

[0014] The layer thickness should be between 0.2 mm and 1 mm, preferably 0.5 mm, to ensure a certain degree of mechanical stability and mechanical resilience of the sealant. Two consecutive coats of 0.25 mm each have proven effective in practice. For the protective effect, the surface of the sealant only needs to be closed, while the layer thickness can be very thin, for example, less than 0.2 mm.

[0015] It is known that aluminum-based additives can reduce the hydrogen permeability of materials. However, the aluminum in most common dispersion-based materials leads to cracking and / or pore formation when the sealant dries. This means that while hydrogen can no longer penetrate the sealant itself, it can still pass through the cracks and pores, ultimately leaving the surface protected from hydrogen unprotected.

[0016] Therefore, the core idea of ​​the invention is that in addition to aluminum powder, zinc powder, nano silicon dioxide and plasticizer are added to the seal, so that after the seal has dried, a coherent layer remains on the surface to be sealed, which on the one hand has a very low, preferably no permeability to hydrogen and at the same time has essentially no cracks or continuous pores through which the hydrogen could reach the surface to be protected.

[0017] The plasticizer serves to impart a certain elasticity to the sealant matrix, so that fewer, or even no, cracks and pores form when the sealant dries. Nano-silicon dioxide also plays a key role in reducing the formation of pores and cracks when the sealant dries.

[0018] The aluminum and zinc powders form platelet-like structures that reinforce the sealant's matrix, acting as a kind of reinforcement. These aluminum and zinc structures ultimately make the sealant impermeable to hydrogen.

[0019] Advantageous embodiments and variants of the invention emerge from the dependent claims and the following description. The features listed individually in the dependent claims can be combined with each other in any technically reasonable manner, as well as with the features explained in more detail in the following description, and represent other advantageous embodiments of the invention.

[0020] In one embodiment of the sealant, the base material comprises pure acrylate, and / or styrene-acrylate and / or styrene-butadiene. Preferably, the base material consists solely of one of these substances or of a combination thereof. Pure acrylate has established itself as a base for facade paints because it is less harmful to health than, for example, nitro-based paints or alkyd resin varnishes, and also has very good properties such as UV resistance and hiding power. Due to the widespread use of pure acrylate, it is also inexpensive and available in good quality. Whenever pure acrylate is mentioned in this application, this preferably means a dispersion of methyl acrylate and water, which has a solids content of 35-45%, preferably 40%, and preferably contains an emulsifier such as Pemulen at 2-4%, preferably 3%.

[0021] In addition to pure acrylate, styrene acrylate and styrene butadiene are also suitable. These materials give the sealant greater mechanical strength and can be used, for example, where surfaces exposed to greater mechanical stress need to be sealed.

[0022] In a further embodiment of the seal, the plasticizer comprises Plastilit 3060 from BASF and / or APEO-free polypropylene glycol alkylphenyl ether. The plasticizer preferably consists of one of these substances alone or a combination thereof.

[0023] In a further embodiment of the seal, the nano-silicon dioxide, preferably essentially entirely, has a particle size of less than 10 nm. Nano-silicon dioxide is characterized by a particle size in the nano range. Advantageously, the particles are present in a particle size below 10 nm. Since powders generally have a grain size distribution, the particles are essentially present in a particle size below 10 nm, meaning, for example, that at least 90% of the particles have a particle size below 10 nm.

[0024] In a further embodiment of the seal, the aluminum powder has an average grain size of 0.1–50 μm, preferably an average grain size of 30 μm. The average grain size describes the grain size that is most frequently present within the powder. Larger and smaller grains are present, for example, in a Gaussian distribution with smaller proportions. In a further embodiment of the seal, the zinc powder has an average grain size of 0.1–50 μm, preferably an average grain size of 50 μm.

[0025] In a further embodiment of the sealant, the sealant comprises substances in the stated proportions: a. 50-90% pure acrylate and / or b. 1-3% white spirit and / or c. 0.1-1.0% preservative and / or d. 1-5% nano-silicon dioxide and / or e. 3-10% plasticizer and / or f. 1-10% aluminum powder and / or g. 1-10% zinc powder and / or h. 0.5-30% water.

[0026] A seal with the above-mentioned proportions of the respective substances is very suitable as a hydrogen barrier.

[0027] White spirit is a mineral spirit used to reduce the setting temperature of the sealant. Präventol (phenylphenol), for example, can be used as a preservative.

[0028] A sealant composition containing the following substances in the following proportions has proven particularly preferred: a. 80% pure acrylate and / or b. 2% white spirit and / or c. 0.3% preservative and / or d. 2% nano-silicon dioxide and / or e. 5% plasticizer and / or f. 2% aluminum powder and / or g. 5% zinc powder and / or h. 3.7% water. Such a sealant has proven completely impermeable to hydrogen in laboratory tests according to DIN EN ISO 17081 and EP 3 553 210 A1.

[0029] A sealed substrate with a seal according to the invention is characterized in that the seal comprises plasticizer, nano-silicon dioxide, aluminum powder and zinc powder.

[0030] In one embodiment of the sealed substrate, the seal is applied to a surface of the substrate with a layer thickness of at least 0.2 mm. Preferably, the seal is applied in two layers, so that the dried seal on the substrate is formed from two layers, each at least 0.1 mm thick.

[0031] In a further embodiment of the sealed substrate, the substrate comprises iron, steel, and / or fiber-reinforced plastic. The substrate preferably consists of one or more of the aforementioned materials. The substrate preferably forms a pipeline or a container for transporting or storing hydrogen. The substrate can also form all elements that would come into contact with the hydrogen during pipeline or container construction, such as valves, sleeves, or fittings.

[0032] In addition to the seal, a method according to the invention for producing the seal, which can be used as a hydrogen barrier, using a base material is also claimed. The method is characterized by the fact that plasticizer, nano-silicon dioxide, aluminum powder, and zinc powder are added to the base material in a mechanical mixing process.

[0033] During the mixing process, the individual components of the sealant are gradually added to the base material, for example, while continuously stirring with a stirrer. It is important that the mechanical mixing is carried out with as little foam as possible.

[0034] In one embodiment of the process, mechanical mixing takes place under vacuum during the production of the seal. During mechanical mixing, it is important to minimize the introduction of air bubbles into the seal, as these later lead to pores in the seal. Therefore, it is advantageous to perform mechanical mixing under vacuum to prevent air bubbles from being mixed into the seal. It can also be effective to remove any air bubbles from the seal by applying a vacuum after mechanical mixing.

[0035] In another embodiment of the process for producing the sealant, the previously mechanically mixed materials (base material, plasticizer, nano-silicon dioxide, aluminum powder, and zinc powder, as well as any other additives) are fed into a colloidator for processing. This results in the sealant components being mixed as finely as possible, allowing the aluminum powder and zinc powder to form platelet-like structures during the setting of the sealant, which reinforce the sealant.

[0036] According to the invention, a matrix material for a fiber composite material can also be used as a hydrogen barrier, comprising a base material, and characterized in that the matrix material comprises plasticizer, nano-silicon dioxide, aluminum powder, and zinc powder. The plasticizer, the nano-silicon dioxide, the aluminum powder, and the zinc powder also result in impermeability to hydrogen in a matrix material for fiber composite materials. A fiber composite material with the matrix material according to the invention is therefore inherently impermeable to hydrogen and does not require additional sealing to protect against hydrogen penetration.

[0037] In a preferred embodiment of the matrix material, the base material comprises a 2K material. 2K materials have the advantage that the setting process can be precisely adjusted and often offer very good solvent resistance after setting.

[0038] In another preferred embodiment of the matrix material, the base material comprises pure acrylate. Epoxy resin is widely used as a matrix material and has proven effective. However, since epoxy resin becomes brittle upon contact with hydrogen and also tends to form pores and cracks during setting, a different base material must be used. It has been shown that pure acrylate can be used as the base material for the matrix material and can be made impermeable to hydrogen using the additives according to the invention.

[0039] A fiber composite plastic according to the invention comprises a fiber material and a matrix material and is characterized in that the matrix material comprises plasticizer, nano-silicon dioxide, aluminum powder and zinc powder.

[0040] In one embodiment of the fiber-reinforced plastic, the fiber material is embedded in the matrix material. For this purpose, the fiber material is essentially completely surrounded by the matrix material. "Essentially completely" within the meaning of the application means that the fiber material does not necessarily have to be surrounded by matrix material, for example, at its ends on subsequently cut edges of a component made of the fiber-reinforced plastic.

[0041] In a further embodiment of the fiber-reinforced plastic, the fiber material comprises glass fibers, and / or carbon fibers, and / or Kevlar fibers, and / or natural fibers, and / or metallic fibers. The fiber material preferably consists of one or more of the aforementioned materials.

[0042] A method according to the invention for producing a matrix material for a fiber composite material usable as a hydrogen barrier, with a base material, is characterized in that plasticizer, nano-silicon dioxide, aluminum powder and zinc powder are added to the base material in a mixing process with mechanical mixing.

[0043] In one embodiment of the process, mechanical mixing takes place under vacuum during production of the matrix material. During mechanical mixing, it is important that as few air bubbles as possible are introduced into the matrix material, as these lead to pores in the matrix material. It is therefore advantageous if the mechanical mixing takes place under vacuum so that no air bubbles are mixed into the matrix material. It can also be effective if, after mechanical mixing, any air bubbles that may have been mixed in are removed from the matrix material by applying a vacuum. In a further preferred embodiment for producing the matrix material, the previously mechanically mixed materials (base material, plasticizer, nano-silicon dioxide, aluminum powder and zinc powder, as well as any other additives) are fed to a colloidator for processing.As a result, the aluminum powder and zinc powder can form platelet-like structures during the setting of the sealant, which lead to reinforcement of the sealant.

[0044] The present invention will be explained in detail below using exemplary embodiments with reference to the accompanying figures. They show:

[0045] Figure 1 shows a sealed substrate with a substrate in the form of a steel tube with a seal according to the invention arranged on its inside,

[0046] Figure 2 shows a fiber composite plastic with a fiber material embedded in a matrix material according to the invention

[0047] Figure 3 shows a sealed steel substrate with a seal according to the invention arranged on one side.

[0048] In the figures, unless otherwise stated, the same reference symbols designate the same or corresponding components with the same function.

[0049] Figure 1 shows a sealed substrate comprising a substrate 1 in the form of a steel tube with a seal 2 arranged on the inside of the steel tube. The seal 2 is applied in a thin layer compared to the wall of the steel tube, with a thickness of 0.2 mm, while the wall of the steel tube is 3 mm. Hydrogen cannot penetrate the seal 2, preventing the inside of the steel tube from coming into contact with the hydrogen. This also prevents hydrogen from escaping through the steel tube into the environment.

[0050] Figure 2 shows a fiber composite plastic with a fiber material 3 embedded in a matrix material 4. The matrix material 4 completely surrounds the fibers of the fiber material 3 and is chemically cured, so that a mechanically stable fiber composite plastic is formed from the fiber material 3 and the matrix material.

[0051] Figure 3 shows a sealed substrate 1 made of steel with a seal 2 according to the invention arranged on one side. The seal 2 was applied to one side of the substrate 1 made of steel in two layers, each with a layer thickness of approximately 0.1 mm.

[0052] The sealant is composed of the following substances in the following proportions: a. 80% pure acrylate and / or b. 2% white spirit and / or c. 0.3% preservative and / or d. 2% nano-silicon dioxide and / or e. 5% plasticizer and / or f. 2% aluminum powder and / or g. 5% zinc powder and / or h. 3.7% water.

[0053] The substrate 1 from Fig. 3, sealed on one side with sealant 2, was subjected to a permeation measurement using an electrochemical measuring device according to DIN EN ISO 17081 and EP 3 553 210 A1. Sealant 1 proved to be completely impermeable to hydrogen in the laboratory tests conducted.

[0054] List of reference symbols

[0055] 1 Substrate 2 Sealing

[0056] 3 Fiber material

[0057] 4 Matrix material

Claims

Patent claims Sealing usable as a hydrogen barrier, with a base Material, characterized in that the seal comprises plasticizer, nano-silicon dioxide, aluminum powder, and zinc powder. Seal according to the preceding claim, characterized in that the base material comprises, preferably consists of, pure acrylate, and / or styrene-acrylate and / or styrene-butadiene. Seal according to one of the preceding claims, characterized in that the plasticizer comprises, preferably consists of, Plastilit and / or free polypropylene glycol alkyl hemyl ether. Seal according to one of the preceding claims, characterized in that the nano-silicon dioxide, preferably substantially entirely, has a particle size of less than 10 nm. Seal according to one of the preceding claims, characterized in that the aluminum powder has an average grain size of 0.1 - 50 pm, preferably an average grain size of 30 pm.Sealing according to one of the preceding claims, characterized in that the zinc powder has an average grain size of 0.1 - 50 pm, preferably an average grain size of 50 pm. Sealing according to one of the preceding claims, characterized in that the seal comprises substances in the stated proportions:. a. 50 - 90% pure acrylate and / or b. 1 - 3% white spirit and / or c. 0.1 - 1.0% preservative and / or d. 1 - 5% nano-silicon dioxide and / or e. 3 - 10% plasticizer and / or f. 1 - 10% aluminum powder and / or g. 1 - 10% zinc powder and / or h. 0.5 - 30% water.

8. Sealed substrate with a seal according to one of the preceding claims, characterized in that the seal comprises plasticizer, nano-silicon dioxide, aluminum powder and zinc powder.

9. Sealed substrate according to the preceding claim, characterized in that the seal is arranged on a surface of the substrate with a layer thickness of at least 0.2 mm, preferably that the seal comprises two layers of at least 0.1 mm each.

10. Sealed substrate according to one of the two preceding claims, characterized in that the substrate comprises, preferably consists of, iron, and / or steel and / or fiber-reinforced plastic.

11. A method for producing a seal usable as a hydrogen barrier, with a base material, characterized in that plasticizer, nano-silicon dioxide, aluminum powder and zinc powder are added to the base material in a mixing process with mechanical mixing.

12. Method according to the preceding claim, characterized in that in the production of the seal, mechanical mixing under vacuum Vacuum is carried out. Experience according to one of claims 8 to 9, characterized in that a colloidator is used to process the mechanically mixed substances during production of the seal. Matrix material for a fiber composite plastic usable as a hydrogen barrier, with a base material, characterized in that the matrix material comprises plasticizer, nano-silicon dioxide, aluminum powder and zinc powder. Matrix material according to the preceding claim, characterized in that the base material comprises a 2K material. Matrix material according to the preceding claim, characterized in that the base material comprises pure acrylate, preferably consists thereof. Fiber composite plastic comprising a fiber material, and a matrix material according to one of the four preceding claims, characterized in that the matrix material comprises plasticizer, nano-silicon dioxide, aluminum powder and zinc powder.Fiber-reinforced plastic according to the preceding claim, characterized in that the fiber material is embedded in the matrix material. Fiber-reinforced plastic according to one of the two preceding claims, characterized in that the fiber material comprises glass fibers, and / or carbon fibers, and / or Kevlar fibers, and / or natural fibers, and / or metallic fibers. preferably, consists of it. A process for producing a matrix material for a fiber composite material usable as a hydrogen barrier, comprising a base material, characterized in that plasticizer, nano-silicon dioxide, aluminum powder, and zinc powder are added to the base material in a mixing process with mechanical mixing. A process according to the preceding claim, characterized in that, during the production of the matrix material, the mechanical mixing takes place under vacuum. A process according to one of claims 14 to 15, characterized in that, during the production of the matrix material, a colloidator is used to process the mechanically mixed substances.

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